Mining tailings as raw materials for reaction-sintered aluminosilicate ceramics: Effect of mineralogical composition on microstructure and properties

This paper presents studies on the utilization of aluminosilicate-based mining tailings as raw materials for mullite-based ceramics. Based on the 3:2 stoichiometric composition, mullite was synthesised by reactive sintering with a series of powder mixtures with alumina additions. X-ray diffractometry and scanning electron microscopy analyses revealed that, at the specific mineralogical composition, mullite structure formed surrounded by an amorphous glass phase in reaction-sintered powder mixtures. Results demonstrated that the chemical and mineralogical composition of mining tailings do have an effect on mullite formation possibilities and, only with the particular mineralogical composition, the mullite formation is possible regardless of the correct Al:Si ratio in tailings. Physical and mechanical properties of the formed ceramics were defined, showing comparable values to 3:2 mullite reference. Mullite structure formation enables a better thermal resistance up to above 1450 °C of the formed tailings-based ceramics compared to other aluminosilicates, reflecting their utilization potential for refractory ceramic applications.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science, Research group: Materials Characterization, VTT Technical Research Centre of Finland, Geologian tutkimuskeskus
Contributors: Karhu, M., Lagerbom, J., Solismaa, S., Honkanen, M., Ismailov, A., Räisänen, M. L., Huttunen-Saarivirta, E., Levänen, E., Kivikytö-Reponen, P.
Pages: 4840-4848
Publication date: Mar 2019
Peer-reviewed: Yes
Early online date: 2018

Publication information

Journal: Ceramics International
Volume: 45
Issue number: 4
ISSN (Print): 0272-8842
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Ceramics and Composites, Process Chemistry and Technology, Surfaces, Coatings and Films, Materials Chemistry
Keywords: Mining tailings, Mullite, Reaction sintering, Refractory ceramics, Utilization

Bibliographical note

EXT="Lagerbom, Juha"

Source: Scopus
Source ID: 85057276435

Research output: Contribution to journalArticleScientificpeer-review

Cost-optimal energy performance measures in a new daycare building in cold climate

New municipal service buildings must be energy effective, and cost-optimality is one of the criteria for selecting the suitable energy performance improvement measures. A daycare building in a cold climate was studied by means of simulation-based, multi-objective optimisation. Using a genetic algorithm, both target energy use and life-cycle cost of the selected measures were minimised. It was found that extensive insulation of the building envelope is not a cost-optimal method to reduce the daycare building energy use. Improving energy efficiency of the ventilation system, utilising solar energy on-site and employing a light control strategy are preferable ways of improving the building energy performance. Ground-source heat pump is a more cost-optimal heating system for the daycare building than district heating. The cost-optimal sizing of the heat pump is small, only 28% of the required maximum heating power. Abbreviations: AHU: air handling unit; CAV: constant air volume; COMBI: comprehensive development of nearly zero-energy municipal service buildings; COP: coefficient of performance; DH: district heating; DHW: domestic hot water; EPBD: energy performance of buildings directive; EU: European Union; FINVAC: Finnish Association of HVAC Societies; GSHP: ground-source heat pump; HRU: heat recovery unit; IDA ICE: IDA Indoor Climate and Energy; LED: light-emitting diode; MOBO: multi-objective building optimisation tool; NSGA-II: Non-dominated Sorting Genetic Algorithm II; nZEB: nearly zero-energy building; PV: photovoltaic; TRY: test reference year; VAV: variable air volume; ZEB: zero-energy building

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Civil Engineering, Equa Simulation Finland Oy, Aalto University, Sweco Finland Oy
Contributors: Sankelo, P., Jokisalo, J., Nyman, J., Vinha, J., Sirén, K.
Number of pages: 19
Pages: 104-122
Publication date: 2019
Peer-reviewed: Yes
Early online date: 15 Mar 2018

Publication information

Journal: International Journal of Sustainable Energy
Volume: 38
Issue number: 2
ISSN (Print): 1478-6451
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Fuel Technology, Energy(all), Process Chemistry and Technology, Fluid Flow and Transfer Processes
Keywords: Building simulation, daycare building, life-cycle cost, multi-objective optimisation, simulation-based optimisation, target energy use
URLs: 
Source: Scopus
Source ID: 85043677926

Research output: Contribution to journalArticleScientificpeer-review

Effect of apartment building energy renovation on hourly power demand

Optimal energy renovations of apartment buildings in Finland have a great impact on annual energy demand. However, reduction of energy demand does not necessarily translate into similar changes in peak power demand. Four different types of apartment buildings, representing the Finnish apartment building stock, were examined after optimal energy retrofits to see the influence of retrofitting on hourly power demand. Switching from district heating to ground-source heat pumps reduced emissions significantly under current energy mix. However, the use of ground-source heat pumps increased hourly peak electricity demand by 46–153%, compared to district heated apartment buildings. The corresponding increase in electrical energy demand was 30–108% in the peak month of January. This could increase the use of high emission peak power plants and negate some of the emission benefits. Solar thermal collectors and heat recovery systems could reduce purchased heating energy to zero in summer. Solar electricity could reduce median power demand in summer, but had only a little effect on peak power demand. The reduction in peak power demand after energy retrofits was less than the reduction in energy demand.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Civil Engineering, Aalto University, Nanjing Tech University
Contributors: Hirvonen, J., Jokisalo, J., Heljo, J., Kosonen, R.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: International Journal of Sustainable Energy
ISSN (Print): 1478-6451
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Fuel Technology, Energy(all), Process Chemistry and Technology, Fluid Flow and Transfer Processes
Keywords: apartment building, district heating, energy performance, Energy retrofits, greenhouse gas emissions, power demand
Source: Scopus
Source ID: 85065643393

Research output: Contribution to journalArticleScientificpeer-review

Towards the EU emissions targets of 2050: optimal energy renovation measures of Finnish apartment buildings

Member countries of the European Union have released targets to reduce carbon dioxide emissions by 80% by the year 2050. Energy use in buildings is a major source of these emissions, which is why this study focused on the cost-optimal renovation of Finnish apartment buildings. Apartment buildings from four different construction years (pre-1976, 1976–2002, 2003–2009 and post-2010) were modelled, using three different heating systems: district heating, ground-source heat pump and exhaust air heat pump. Multi-objective optimisation was utilised to find the most cost-effective energy renovation measures. Most cost-effective renovation measures were ground-source heat pumps, demand-based ventilation and solar electricity. Additional thermal insulation of walls was usually too expensive. By performing only the cost-effective renovations, the emissions could be reduced by 80%, 82%, 69% and 68%, from the oldest to the newest buildings, respectively. This could be done with the initial investment cost of 296, 235, 115 and 104 €/m2, respectively.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Civil Engineering, Aalto University, Nanjing Tech University
Contributors: Hirvonen, J., Jokisalo, J., Heljo, J., Kosonen, R.
Publication date: 2019
Peer-reviewed: Yes
Early online date: 2018

Publication information

Journal: International Journal of Sustainable Energy
Volume: 38
Issue number: 7
ISSN (Print): 1478-6451
Original language: English
ASJC Scopus subject areas: Renewable Energy, Sustainability and the Environment, Fuel Technology, Energy(all), Process Chemistry and Technology, Fluid Flow and Transfer Processes
Keywords: apartment building, Cost-optimal renovation, energy performance, greenhouse gas emissions, multi-objective optimisation
Source: Scopus
Source ID: 85058681434

Research output: Contribution to journalArticleScientificpeer-review

Volatile fatty acid adsorption on anion exchange resins: kinetics and selective recovery of acetic acid

The removal of volatile fatty acids was examined through adsorption on anion exchange resins in batch systems. During the initial screening step, granular activated carbon and 11 anion exchange resins were tested and the resins Amberlite IRA-67 and Dowex optipore L-493 were chosen for further investigation. The adsorption kinetics and diffusion mechanism and adsorption isotherms of the two resins for VFA were evaluated. Based on the selective adsorption capacity of the resins, a sequential batch process was tested to achieve separation of acetic acid from the VFA mixture and selective recoveries > 85% acetic acid and ~ 75% propionic acid was achieved.

General information

Publication status: E-pub ahead of print
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science and Environmental Engineering, Hydraulic and Environmental Engineering (IHE) Inst. for Water Education, Institute for Water Education
Contributors: Eregowda, T., Rene, E. R., Rintala, J., Lens, P. N.
Publication date: 2019
Peer-reviewed: Yes

Publication information

Journal: Separation Science and Technology (Philadelphia)
ISSN (Print): 0149-6395
Original language: English
ASJC Scopus subject areas: Chemistry(all), Chemical Engineering(all), Process Chemistry and Technology, Filtration and Separation
Keywords: anion-exchange resins, Brunauer-Emmett-Teller model, selective recovery, Volatile fatty acids
Source: Scopus
Source ID: 85065190589

Research output: Contribution to journalArticleScientificpeer-review

The effect of carbon and nickel additions on the precursor synthesis of Cr3C2-Ni nanopowder

Decreasing crystal size to nanoscale is a proven method to enhance material properties. In this study, nanosize Cr3C2 and Cr3C2-Ni were synthetized and the reaction sequence was studied. Aqueous precursors using only water-soluble raw materials with varying carbon contents and a nickel addition were spray-dried. Glycine was used as a carbon source and chromium acetate hydroxide as a chromium source in the precursor solutions. Nickel nitrate hexahydrate was introduced as a nickel source to yield a metallic binder into the carbide nanopowder.Resulting powders were heat-treating to identify an applicable precursor composition producing the targeted Cr3C2 phase with crystal size of tens of nanometers. Thermal synthesis tests of the precursor powders to yield Cr3C2 took place at a temperature between 900 and 1300 °C under an Argon atmosphere. The synthesis of nanosize Cr3C2-Ni powder was successful at 1000 °C in 30 min, in a case of the best precursor. In order to produce the carbide phase with no residual oxide traces, relative carbon load has to be 48 wt%, while the stoichiometric amount of carbon in Cr3C2 is 13 wt%. When also introducing the nickel source into the precursor, an even higher carbon load was required. The carbon surplus needed to enable the Cr3C2 synthesis attributes to the non-homogeneity of the precursor composition.The chemical synthesis starting from water-soluble raw materials is a promising way of preparing nanosize Cr3C2-Ni with the targeted phase configuration.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science, Research group: Materials Characterization, VTT Technical Research Centre of Finland
Contributors: Kaunisto, K., Kotilainen, M., Karhu, M., Lagerbom, J., Vuorinen, T., Honkanen, M., Vippola, M., Turunen, E.
Pages: 9338-9346
Publication date: 1 Jun 2018
Peer-reviewed: Yes
Early online date: 2018

Publication information

Journal: Ceramics International
Volume: 44
Issue number: 8
ISSN (Print): 0272-8842
Ratings: 
  • Scopus rating (2018): CiteScore 3.5 SJR 0.888 SNIP 1.279
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Ceramics and Composites, Process Chemistry and Technology, Surfaces, Coatings and Films, Materials Chemistry
Keywords: A. Nanosize CrC synthesis, A. Powders: chemical preparation, B. Grain size, D. Carbides, E. Wear parts

Bibliographical note

EXT="Vuorinen, Tommi"
EXT="Lagerbom, Juha"
EXT="Kaunisto, Kimmo"

Source: Scopus
Source ID: 85042300396

Research output: Contribution to journalArticleScientificpeer-review

Influence of the phosphate glass melt on the corrosion of functional particles occurring during the preparation of glass-ceramics

We report our findings on the impact of the glass composition on the corrosion of microparticles occurring during the preparation of glass-ceramics using the direct doping method. Microparticles (MPs) with the composition Sr4Al14O25:Eu2+,Dy3+ with blue-green persistent luminescence were chosen as the changes in their spectroscopic properties can be related to the MPs’ corrosion. The MPs were added in phosphate-based glasses with different compositions. When using the same doping parameters, the glass system with the composition 90NaPO3-10Na2O (mol%) was found to be the least corrosive on the MPs whereas the glass system with the composition 90NaPO3-10NaF (mol%) is the most corrosive on the MPs probably due to their different viscosity at 575 °C, the temperature at which the MPs are added in the glass melts.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Photonics, Research group: Nanophotonics, Turun Yliopisto/Turun Biomateriaalikeskus, Laboratory of Photonics
Contributors: Ojha, N., Laihinen, T., Salminen, T., Lastusaari, M., Petit, L.
Pages: 11807-11811
Publication date: Jun 2018
Peer-reviewed: Yes
Early online date: 1 Jan 2018

Publication information

Journal: Ceramics International
Volume: 44
Issue number: 10
ISSN (Print): 0272-8842
Ratings: 
  • Scopus rating (2018): CiteScore 3.5 SJR 0.888 SNIP 1.279
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Ceramics and Composites, Process Chemistry and Technology, Surfaces, Coatings and Films, Materials Chemistry
Keywords: Corrosion, Direct doping method, Glass melt, Phosphate glass-ceramics, SrAlO:Eu, Dy microparticles
Source: Scopus
Source ID: 85044921933

Research output: Contribution to journalArticleScientificpeer-review

The effects of laser patterning 10CeTZP-Al2O3 nanocomposite disc surfaces: Osseous differentiation and cellular arrangement in vitro

Customized square grid arrangements of different groove depths (1.0, 1.5 and 3.0 μm) and separations (10 and 30 μm) were successfully laser patterned, using a nanosecond pulsed fibre laser, on the surface of 10 mol% ceria-stabilized zirconia and alumina (10CeTZP-Al2O3) nanocomposite discs (diameter: 10 mm; thickness: 1.5 mm). The patterned surfaces and the in vitro biological response of osteoblasts (SAOS-2) towards them were thoroughly analysed. In terms of composition, the laser treatment was found to cause superficial monoclinic-tetragonal zirconia phase transformation and alumina evaporation. In vitro, the most effective grid configuration for osseous differentiation was found to be 1.5 μm groove depth and 10 μm groove separation, and confocal microscopy revealed that the cells show a tendency to be sorted as groove depth increases. It is thought that custom-made patterns could be produced to guide cell attachment in vivo, which could favour implant integration and reduce healing time.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science, Mechanical Engineering and Industrial Systems, Nanoker Research, Universidad de Oviedo
Contributors: Goyos-Ball, L., Prado, C., Díaz, R., Fernández, E., Ismailov, A., Kumpulainen, T., Levänen, E., Torrecillas, R., Fernández, A.
Pages: 9472-9478
Publication date: Jun 2018
Peer-reviewed: Yes
Early online date: 2018

Publication information

Journal: Ceramics International
Volume: 44
Issue number: 8
ISSN (Print): 0272-8842
Ratings: 
  • Scopus rating (2018): CiteScore 3.5 SJR 0.888 SNIP 1.279
Original language: English
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Ceramics and Composites, Process Chemistry and Technology, Surfaces, Coatings and Films, Materials Chemistry
Keywords: Alumina, Cellular arrangement, Ceramic nanocomposite, Laser patterning, Osseous differentiation, Zirconia
Source: Scopus
Source ID: 85042621677

Research output: Contribution to journalArticleScientificpeer-review

Aqueous synthesis of Z-scheme photocatalyst powders and thin-film photoanodes from earth abundant elements

Solid-state narrow band gap semiconductor heterostructures with a Z-scheme charge-transfer mechanism are the most promising photocatalytic systems for water splitting and environmental remediation under visible light. Herein, we construct all-solid Z-scheme photocatalytic systems from earth abundant elements (Ca and Fe) using an aqueous synthesis procedure. A novel Z-scheme two-component Fe2O3/Ca2Fe2O5 heterostructure is obtained in a straightforward manner by soaking various iron-containing nanoparticles (amorphous and crystalline) with Ca(NO3)2 and performing short (20min) thermal treatments at 820°C. The obtained powder materials show high photocatalytic performances for methylene blue dye degradation under visible light (45 mW/cm2), exhibiting a rate constant up to 0.015min-1. The heterostructure exhibits a five-fold higher activity compared to that of pristine hematite. The experiments show that amorphous iron-containing substrate nanoparticles trigger the Fe2O3/Ca2Fe2O5 heterostructure formation. We extended our study to produce Fe2O3/Ca2Fe2O5 nanoheterostructure photoanodes via the electrochemical deposition of amorphous iron-containing sediment were used. The visible-light (15mW/cm2) photocurrent increases from 183μA/cm2 to 306μA/cm2 after coupling hematite and Ca2Fe2O5. Notably, the powders and photoanodes exhibit distinct charge-transfer mechanisms evidenced by the different stabilities of the heterostructures under different working conditions.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Photonics, Riga Technical University, Institute of Physics, University of Tartu, Institute of Solid State Physics University of Latvia, Riga Technical University
Contributors: Šutka, A., Vanags, M., Joost, U., Šmits, K., Ruža, J., Ločs, J., Kleperis, J., Juhna, T.
Number of pages: 10
Pages: 2606-2615
Publication date: 1 Apr 2018
Peer-reviewed: Yes

Publication information

Journal: Journal of Environmental Chemical Engineering
Volume: 6
Issue number: 2
ISSN (Print): 2213-3437
Ratings: 
  • Scopus rating (2018): CiteScore 4.09 SJR 0.876 SNIP 1.198
Original language: English
ASJC Scopus subject areas: Chemical Engineering (miscellaneous), Waste Management and Disposal, Pollution, Process Chemistry and Technology
Keywords: Hematite, Photoanode, Photocatalyst, Photoelectrochemical properties, Z-scheme

Bibliographical note

INT=fot, ”Joost, U.”

Source: Scopus
Source ID: 85045209610

Research output: Contribution to journalArticleScientificpeer-review

Deactivation of Pt/SiO2-ZrO2 diesel oxidation catalysts by sulphur, phosphorus and their combinations

The impact of sulphur, phosphorus and water and their co-exposure on a monolith-type Pt/SiO2-ZrO2 diesel oxidation catalyst was investigated. The accelerated laboratory-scale sulphur treatments for Pt/SiO2-ZrO2 were done with and without water (S- and SW-treatments, respectively) at 400 °C. Similarly, the phosphorus treatment with water (PW-treatment) as well as the co-exposure of phosphorus, sulphur and water (PSW-treatment) were also done to find out the interactions between the impurities. The studied catalysts were characterized by using several techniques and the activity of the catalyst was tested in lean diesel exhaust gas conditions. Based on the XPS and the elemental analysis, more phosphorus was adsorbed on the Pt/SiO2-ZrO2 catalyst than sulphur. Sulphur, in the presence and absence of water, was found to have a negligible effect on the CO and C3H6 light-off temperatures (T90) over the fresh Pt/SiO2-ZrO2, whereas the T90 values of CO and C3H6 increased by 30–45 °C as a result of the PW-treatment and by 15–35 °C after the PSW-treatment. Based on the Transmission electron microscope (TEM) analyses, no morphological changes on the Pt/SiO2-ZrO2 surfaces were observed due to the phosphorus treatment. Therefore, the reason for the lower activity after the PW-treatment could be the formation of phosphates that are decreasing the specific surface area of the catalyst, blocking the accessibility of the reactants to the catalyst pores and active sites. However, it is worth noting that sulphur decreased the amount of adsorbed phosphorus and thus, inhibited the poisoning effect of phosphorus.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Materials Science, Research group: Materials Characterization, Dinex Ecocat Oy, Univ of Oulu, Aalto University
Contributors: Väliheikki, A., Kärkkäinen, M., Honkanen, M., Heikkinen, O., Kolli, T., Kallinen, K., Huuhtanen, M., Vippola, M., Lahtinen, J., Keiski, R. L.
Number of pages: 11
Pages: 409-419
Publication date: 5 Dec 2017
Peer-reviewed: Yes

Publication information

Journal: Applied Catalysis B-Environmental
Volume: 218
ISSN (Print): 0926-3373
Ratings: 
  • Scopus rating (2017): CiteScore 10.92 SJR 3.152 SNIP 2.367
Original language: English
ASJC Scopus subject areas: Catalysis, Environmental Science(all), Process Chemistry and Technology
Keywords: DOC, Phosphorus, Platinum, Silicon-zirconium oxide, Sulphur dioxide
Source: Scopus
Source ID: 85021933594

Research output: Contribution to journalArticleScientificpeer-review

Photodynamic self–disinfecting surface using pyridinium phthalocyanine

We have synthesized novel phthalocyanine with four pyridyl substituents connected to α-phthalo-positions via direct C-C bond. The Zn complex and tetracationic derivatives of phthalocyanine were also synthesized and the dyes were impregnated into filter paper to prepare photoactive antimicrobial surface. The photodynamic antimicrobial efficacy of the dyed paper samples was evaluated by a simple and fast setup using bioluminescent microbes. Escherichia coli and Acinetobacter baylyi ADP1 strains carrying bacterial luciferase genes were used in the screening experiment. The most efficient compound, tetracationic zinc derivative 8, was investigated further. The compound was highly water soluble, had high molar absorptivity and exhibited good adhesion to the filter paper without leaching into the solution. The singlet oxygen quantum yield of tetracationic zinc derivative 8 in water was found out to be 30 ± 20%. According to the cell viability assay test performed on E. coli wild type in solution, the molecule had similar or better photo toxicity as the reference photosensitizer, tetrakis (1-methyl-pyridinium-4-yl)porphyrin (TMPyP). Antimicrobial efficacy of the dye 8 on photoactive surface was studied by live cell assessment through colony forming unit (CFU) counting. The colored surface demonstrated 3 log reduction in CFU against E. coli and A. baylyi ADP1 just after 1 h of illumination with the white light of low intensity.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Research group: Bio- and Circular Economy, Institut für Physik
Contributors: George, L., Müller, A., Röder, B., Santala, V., Efimov, A.
Number of pages: 9
Pages: 334-342
Publication date: 1 Dec 2017
Peer-reviewed: Yes

Publication information

Journal: Dyes and Pigments
Volume: 147
ISSN (Print): 0143-7208
Ratings: 
  • Scopus rating (2017): CiteScore 3.59 SJR 0.819 SNIP 1.005
Original language: English
ASJC Scopus subject areas: Chemical Engineering(all), Process Chemistry and Technology
Keywords: Antimicrobial, Photodynamic antimicrobial chemotherapy, Pyridinium phthalocyanine, Self-disinfecting surface, Singlet oxygen
Source: Scopus
Source ID: 85027896139

Research output: Contribution to journalArticleScientificpeer-review

New Evidence for the Mechanism of Action of a Type-2 Diabetes Drug Using a Magnetic Bead-Based Automated Biosensing Platform

The mechanism of action (MOA) of the first line type-2 diabetes drug metformin remains unclear despite its widespread usage. However, recent evidence suggests that the mitochondrial copper (Cu)-binding action of metformin may contribute toward the drug's MOA. Here, we present a novel biosensing platform for investigating the MOA of metformin using a magnetic microbead-based agglutination assay which has allowed us to demonstrate for the first time the interaction between Cu and metformin at clinically relevant low micromolar concentrations of the drug, thus suggesting a potential pathway of metformin's blood-glucose lowering action. In this assay, cysteine-functionalized magnetic beadswere agglutinated in the presence of Cu due to cysteine's Cu-chelation property. Addition of clinically relevant doses of metformin resulted in disaggregation of Cu-bridged bead-clusters, whereas the effect of adding a closely related but blood-glucose neutral drug propanediimidamide (PDI) showed completely different responses to the clusters. The entire assay was integrated in an automated microfluidics platform with an advanced optical imaging unit by which we investigated these aggregation-disaggregation phenomena in a reliable, automated, and user-friendly fashion with total assay time of 17 min requiring a sample (metformin/PDI) volume of 30 μL. The marked difference of Cu-binding action between the blood-glucose lowering drug metformin and its inactive analogue PDI thus suggests that metformin's distinctive Cu-binding properties may be required for its effect on glucose homeostasis. The novel automated platform demonstrating this novel investigation thus holds the potential to be utilized for investigating significant and sensitive molecular interactions via magnetic bead-based agglutination assay.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Chemistry and Bioengineering, Danmarks Tekniske Universitet, DTU Informatik, University of Dundee, Academia Sinica Taiwan
Contributors: Uddin, R., Nur-E-Habiba, N., Rena, G., Hwu, E. T., Boisen, A.
Number of pages: 8
Pages: 1329-1336
Publication date: 22 Sep 2017
Peer-reviewed: Yes

Publication information

Journal: ACS Sensors
Volume: 2
Issue number: 9
ISSN (Print): 1424-8220
Ratings: 
  • Scopus rating (2017): CiteScore 3.23 SJR 0.584 SNIP 1.567
Original language: English
ASJC Scopus subject areas: Bioengineering, Fluid Flow and Transfer Processes, Process Chemistry and Technology, Instrumentation
Keywords: agglutination assay, biosensor, magnetic beads, metformin, molecular interactions, optical imaging, type-2 diabetes

Bibliographical note

INT=keb,"Nur-E-Habiba, N."

Source: Scopus
Source ID: 85029817525

Research output: Contribution to journalArticleScientificpeer-review

Accelerated deactivation studies of the natural-gas oxidation catalyst-Verifying the role of sulfur and elevated temperature in catalyst aging

Accelerated deactivation, caused by thermal aging (TA) and/or sulfur+water poisoning (SW), of the PtPd/γ-Al2O3 natural-gas oxidation catalyst was studied. Thermal aging and poisoning treatments were performed separately and with varied combinations and comprehensive characterization of the catalyst was carried out after each step. The fresh catalyst has small, oxidized PtPd particles (<5nm) uniformly distributed in the γ-alumina washcoat. After the SW-treatment, a small amount of bulk aluminum sulfate was observed near the slightly grown noble metal particles. During the thermal aging, γ-alumina changed to δ-/θ- and α-alumina. In addition, total decomposition of oxidized Pt and partly decomposition of oxidized Pd occurred resulting in the formation of the grown noble metal particles with a bimetallic PtPd core and a polycrystalline PdO shell. Also few, small (~5nm) bimetallic PtPd particles were still detected. In the TA+SW-treated catalyst with grown noble metal particles, a small amount of bulk aluminum sulfate was detected and it was randomly distributed over the noble metal particles and washcoat. The activity in the terms of methane conversion over the TA-, SW-, and SW+TA-treated catalysts was similar but it was decreased compared to the fresh catalyst. The activity of the TA+SW-treated catalyst was drastically decreased compared to the fresh catalyst due to significant morphological changes and aluminum sulfate formation.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Materials Science, Research group: Materials Characterization, University of Oulu, Aalto University, Chalmers University of Technology, Dinex Ecocat Oy
Contributors: Honkanen, M., Kärkkäinen, M., Kolli, T., Heikkinen, O., Viitanen, V., Zeng, L., Jiang, H., Kallinen, K., Huuhtanen, M., Keiski, R. L., Lahtinen, J., Olsson, E., Vippola, M.
Number of pages: 10
Pages: 439-448
Publication date: 2016
Peer-reviewed: Yes
Early online date: 1 Oct 2015

Publication information

Journal: Applied Catalysis B-Environmental
ISSN (Print): 0926-3373
Ratings: 
  • Scopus rating (2016): CiteScore 8.86 SJR 2.693 SNIP 2.208
Original language: English
ASJC Scopus subject areas: Catalysis, Process Chemistry and Technology, Environmental Science(all)
Keywords: Deactivation, Palladium, Platinum, Sulfur poisoning, Thermal aging
Electronic versions: 
URLs: 
Source: Scopus
Source ID: 84943638016

Research output: Contribution to journalArticleScientificpeer-review

Metrics for polyphonic sound event detection

This paper presents and discusses various metrics proposed for evaluation of polyphonic sound event detection systems used in realistic situations where there are typically multiple sound sources active simultaneously. The system output in this case contains overlapping events, marked as multiple sounds detected as being active at the same time. The polyphonic system output requires a suitable procedure for evaluation against a reference. Metrics from neighboring fields such as speech recognition and speaker diarization can be used, but they need to be partially redefined to deal with the overlapping events. We present a review of the most common metrics in the field and the way they are adapted and interpreted in the polyphonic case. We discuss segment-based and event-based definitions of each metric and explain the consequences of instance-based and class-based averaging using a case study. In parallel, we provide a toolbox containing implementations of presented metrics.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Signal Processing, Research group: Audio research group
Contributors: Mesaros, A., Heittola, T., Virtanen, T.
Publication date: 2016
Peer-reviewed: Yes

Publication information

Journal: Applied Sciences
Volume: 6
Issue number: 6
Article number: 162
ISSN (Print): 2076-3417
Ratings: 
  • Scopus rating (2016): SJR 0.315 SNIP 0.799
Original language: English
ASJC Scopus subject areas: Fluid Flow and Transfer Processes, Process Chemistry and Technology, Computer Science Applications, Engineering(all), Materials Science(all), Instrumentation
Keywords: Audio content analysis, Audio signal processing, Computational auditory scene analysis, Evaluation of sound event detection, Everyday sounds, Pattern recognition, Polyphonic sound event detection, Sound events
Source: Scopus
Source ID: 84973574836

Research output: Contribution to journalArticleScientificpeer-review

Enhanced photoactive and photoelectrochemical properties of TiO2 sol-gel coated steel by the application of SiO2 intermediate layer

Photocatalysis is a promising solution for purifying air and water from pollutants, yet more efficient photocatalytic materials are needed. A new approach is proposed in this paper for enhancing the photoactive and photoelectrical properties of anatase TiO2 films by applying an intermediate SiO2 film between the TiO2 film and the stainless steel substrate. TiO2 and SiO2 coatings are synthesized by a sol-gel method and the thickness of TiO2 film is varied in order to obtain improved understanding on the role of thickness in photocatalytic and electrochemical performance. The obtained coatings are systematically characterized in terms of microstructure using such techniques as field-emission scanning electron microscopy (FE-SEM), Raman spectroscopy and X-ray diffraction (XRD), that demonstrate, e.g., the anatase phase structure of the TiO2 films. The enhanced photocatalytic properties of SiO2/TiO2 coatings as compared to TiO2 films are verified using methylene blue (MB) discoloration tests, while the improved photoelectrochemical properties are shown by potentiodynamic i-V scans, open circuit potential (OCP) monitoring and electrochemical impedance spectroscopy (EIS). We attribute the beneficial effect of the intermediate SiO2 film on the photocatalytic and photoelectrochemical performance to the high electrical resistance of the SiO2 that imposes a high-energy barrier for electron transfer and, therefore, (partly) insulates the TiO2 film from the substrate and acts as a capacitor for photo-generated electrons under illumination. The presented results show an effective way of enhancing the photocatalytic performance of anatase TiO2 films.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Engineering materials science and solutions (EMASS), Frontier Photonics, Department of Materials Science, Research group: Ceramic materials, Optoelectronics Research Centre, Research group: Nanophotonics, Research group: Surface Engineering, Research group: Materials Characterization
Contributors: Nikkanen, J. P., Huttunen-Saarivirta, E., Salminen, T., Hyvärinen, L., Honkanen, M., Isotahdon, E., Heinonen, S., Levänen, E.
Number of pages: 11
Pages: 533-543
Publication date: 1 Sep 2015
Peer-reviewed: Yes

Publication information

Journal: Applied Catalysis B-Environmental
Volume: 174-175
ISSN (Print): 0926-3373
Ratings: 
  • Scopus rating (2015): CiteScore 7.72 SJR 2.326 SNIP 2.175
Original language: English
ASJC Scopus subject areas: Catalysis, Process Chemistry and Technology, Environmental Science(all)
Keywords: Electrical resistance, Electrochemical impedance spectroscopy, Photocatalysis, Substrate, Titanium dioxide

Bibliographical note

ORG=mol,0.5
ORG=orc,0.5

Source: Scopus
Source ID: 84937762118

Research output: Contribution to journalArticleScientificpeer-review

Evaluation of crushing strength of spray-dried MgAl2O4 granule beds

The crushing strengths of four different experimental magnesium aluminate spinel (MgAl2O4) granule beds were monitored with the axial die pressing test after heat treatments. Precursor, magnesium hydroxide (Mg(OH)2) and magnesium oxide (MgO) as Mg precursor and aluminium oxide hydroxide Al(O)OH and α-Al2O3 as Al precursor, were used for experimental granules, which were manufactured via a dispersion manufacturing and spray-drying process. After spray-drying, granules were heat treated in air at 1000, 1100, 1200, 1300 and 1400 °C. In order to understand the potential effect of precursor, phase structure, morphology, particle size distribution and density of granules on crushing strength behaviour, scanning X-ray diffraction (XRD) was used together with electron microscopy (SEM) and laser diffraction (LDPA) for characterisation. All precursor mixtures formed spherical granules during the spray-drying process and pure spinel phase structure during heat treatment. The crushing strength test results indicated that the Al precursor clearly affected the crushing strength behaviour of experimental granule beds. The highest strength was observed for granule beds with Al(O)OH) as Al and Mg(OH)2 as Mg precursor.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Department of Materials Science, Engineering materials science and solutions (EMASS), VTT Technical Research Centre of Finland
Contributors: Kanerva, U., Suhonen, T., Lagerbom, J., Levänen, E.
Number of pages: 7
Pages: 8494-8500
Publication date: 1 Aug 2015
Peer-reviewed: Yes

Publication information

Journal: Ceramics International
Volume: 41
Issue number: 7
ISSN (Print): 0272-8842
Ratings: 
  • Scopus rating (2015): CiteScore 2.64 SJR 0.823 SNIP 1.288
Original language: English
ASJC Scopus subject areas: Ceramics and Composites, Process Chemistry and Technology, Electronic, Optical and Magnetic Materials, Surfaces, Coatings and Films, Materials Chemistry
Keywords: Axial pressing, Granule, MgAl<inf>2</inf>O<inf>4</inf> spinel, The crushing strength

Bibliographical note

EXT="Lagerbom, Juha"
EXT="Kanerva, Ulla"

Source: Scopus
Source ID: 84929271760

Research output: Contribution to journalArticleScientificpeer-review

A facile route to synthesis of S-doped TiO2 nanoparticles for photocatalytic activity

There is always a market for cost effective methods of pollution degradation and one of the best areas to keep costs down is through synthesis techniques. This paper provides a simple technique to synthesise porous TiO2 nanoparticles with increased surface area through a scaffold template technique. Their photocatalytic activity is enhanced by incorporating sulphur as a dopant and were validated by analysing the degradation of malachite green (MG). The materials were doped at a molar ratio of 100:1 (Ti:S) and calcined at different temperatures to adjust the anatase/rutile content. Detailed characterisation of the materials was undertaken using XRD, BET, XPS, TEM and FTIR. The nanoparticles displayed a microporous structure and had an increased surface area of 115 m2 g-1 which was reduced by doping and temperature induced phase transformation. Photocatalytic testing showed that the doped materials calcined at 700 °C preformed the best in. It was observed that 20 mg l-1 of MG was decomposed in 30 min using a 40 W UV bulb at pH 9 and the results surpassed those achieved by the commercial catalyst P25 which was also tested for comparison.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Frontier Photonics, Trinity College Dublin, University College Cork, Materials Chemistry and Analysis Group, Centre for Research on Adaptive Nanostructures and Nanodevices
Contributors: McManamon, C., O'Connell, J., Delaney, P., Rasappa, S., Holmes, J. D., Morris, M. A.
Pages: 51-57!
Publication date: 30 May 2015
Peer-reviewed: Yes

Publication information

Journal: Journal of Molecular Catalysis A: Chemical
Volume: 406
ISSN (Print): 1381-1169
Ratings: 
  • Scopus rating (2015): CiteScore 3.93 SJR 1.052 SNIP 1.262
Original language: English
ASJC Scopus subject areas: Catalysis, Physical and Theoretical Chemistry, Process Chemistry and Technology
Keywords: Band gap, Photocatalysis, S-doped, TiO<inf>2</inf>
Source: Scopus
Source ID: 84930210395

Research output: Contribution to journalArticleScientificpeer-review

Large-area arrays of three-dimensional plasmonic subwavelength-sized structures from azopolymer surface-relief gratings

The field of plasmonics allows for confinement and control of light on the nanoscale. Due to potentially strong resonant interactions that light can have with metal nanoscale structures, metals are a good candidate to tailor interactions with light, e.g., periodic arrays of subwavelength metal structures can support extremely narrow resonances and show enhanced transmission. The field of plasmonics has evolved from using simple geometries to the desire to create complex nanostructures for improved control. The availability of fabrication techniques that provide for complex structures, however, is paired with the seemingly inevitable increase in complexity of fabrication techniques themselves. We present a facile and scalable method for the fabrication of periodic arrays of unique three-dimensional subwavelength-sized structures such as tapered holes and pyramidically shaped subwavelength-sized particles. The procedure consists of holographic inscription of a two-dimensional surface-relief grating in an azobenzene-containing polymer film, evaporative gold deposition and broad-beam ion milling of the relief structure. The method allows the fabrication of highly uniform arrays with tunable lattice parameters and dimensions over large sample areas. The optical response of the fabricated structures is determined experimentally and through simulation, which confirm the unique plasmonic response of the structures. While the proposed fabrication method has clear benefits for plasmonics, it could easily be applied also in other fields, for example by using other coating materials.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Frontier Photonics, Delft University of Technology, COMP Centre of Excellence, Department of Applied Physics, Aalto University, Aalto University
Contributors: Moerland, R. J., Koskela, J. E., Kravchenko, A., Simberg, M., Van Der Vegte, S., Kaivola, M., Priimagi, A., Ras, R. H. A.
Number of pages: 7
Pages: 74-80
Publication date: 1 Jan 2014
Peer-reviewed: Yes

Publication information

Journal: Materials Horizons
Volume: 1
Issue number: 1
ISSN (Print): 2051-6347
Original language: English
ASJC Scopus subject areas: Materials Science(all), Mechanics of Materials, Process Chemistry and Technology, Electrical and Electronic Engineering
Source: Scopus
Source ID: 84900804343

Research output: Contribution to journalArticleScientificpeer-review

Effects of storage on characteristics and hygienic quality of digestates from four co-digestion concepts of manure and biowaste

This study evaluated the effects of storage in northern winter conditions (5 °C) on the characteristics and nutrients separation of digestates from co-digestion of manure and biowaste as well as the hygienic quality of the digestates after digestion and storage. During 3-11 months' storage average nitrogen losses and reductions of total solids (TS) and volatile solids (VS) were 0-15%. With some exceptions, soluble chemical oxygen demand (SCOD) had increased slightly (from ∼6.5 to ∼7.5 g/l) after 3 months' storage, while after 9-11 months' it had decreased from 8.3-11 to 5.6-8.4 g/l. The concentrations of Ptot and PO4-P in the separated liquid fractions decreased 40-57% after 3 months' storage and 71-91% after 9 months' storage compared to the initial concentrations. The methane potential losses during 9-11 months' storage corresponded 0-10% of the total methane potential without storage. The hygienic quality of the digestates from the 55 °C reactor and during storage fulfilled the Animal By-Products Regulation (ABPR) demands while the 35 °C digestate contained 0-105 cfu/g of indicator bacteria (faecal coliforms, enterobacteria, enterococcus) and >10 cfu/g of spiked salmonella, which amounts decreased slowly during storage. Sulphite reducing clostridia was not affected by either digestion or storage.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Jyväskylän yliopisto, University of Jyväskylä
Contributors: Paavola, T., Rintala, J.
Number of pages: 10
Pages: 7041-7050
Publication date: Oct 2008
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 99
Issue number: 15
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2008): SJR 1.736 SNIP 2.73
Original language: English
ASJC Scopus subject areas: Agronomy and Crop Science, Food Science, Process Chemistry and Technology, Applied Microbiology and Biotechnology, Bioengineering, Environmental Engineering, Waste Management and Disposal
Keywords: Biowaste, Digestate, Hygienic quality, Manure, Solid/liquid separation
Source: Scopus
Source ID: 44449089925

Research output: Contribution to journalArticleScientificpeer-review

Storing energy crops for methane production: Effects of solids content and biological additive

The effect of storage on chemical characteristics and CH4 yield (taking into account loss of VS during storage) of a mixture of grasses and ryegrass, ensiled as such (low solids content) and after drying (medium and high solids) with and without biological additive, were studied in field and laboratory trials. Up to 87% and 98% of CH4 yield was preserved with low solids grass (initial TS 15.6%) and high solids ryegrass (initial TS 30.4%), respectively, after storage for 6 months, while under suboptimal conditions at most 37% and 52% of CH4 yield were lost. Loss in CH4 yield was mainly due to VS loss, presumably caused by secondary fermentation as also suggested by increasing pH during storage. Biological additive did not assist in preserving the CH4 yield.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Jyväskylän yliopisto, University of Jyväskylä
Contributors: Pakarinen, O., Lehtomäki, A., Rissanen, S., Rintala, J.
Number of pages: 9
Pages: 7074-7082
Publication date: Oct 2008
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 99
Issue number: 15
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2008): SJR 1.736 SNIP 2.73
Original language: English
ASJC Scopus subject areas: Agronomy and Crop Science, Food Science, Process Chemistry and Technology, Applied Microbiology and Biotechnology, Bioengineering, Environmental Engineering, Waste Management and Disposal
Keywords: Anaerobic digestion, Biogas, Energy crop, Grass, Storage
Source: Scopus
Source ID: 44449146372

Research output: Contribution to journalArticleScientificpeer-review

Group-specific quantification of methanotrophs in landfill gas-purged laboratory biofilters by tyramide signal amplification-fluorescence in situ hybridization

The aim of this study was to quantitatively analyse methanotrophs in two laboratory landfill biofilters at different biofilter depths and at temperatures which mimicked the boreal climatic conditions. Both biofilters were dominated by type I methanotrophs. The biofilter depth profiles showed that type I methanotrophs occurred in the upper layer, where relatively high O2 and low CH4 concentrations were present, whereas type II methanotrophs were mostly distributed in the zone with high CH4 and low O2 concentrations. The number of type I methanotrophic cells declined when the temperature was raised from 15 °C to 23 °C, but increased when lowered to 5 °C. A slight decrease in type II methanotrophs was also observed when the temperature was raised from 15 °C to 23 °C, whereas cell numbers remained constant when lowered to 5 °C. The results indicated that low temperature conditions favored both type I and type II methanotrophs in the biofilters.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Jyväskylän yliopisto, University of Tampere Institute of Medical Technology, University of Jyväskylä
Contributors: Wang, H., Einola, J., Heinonen, M., Kulomaa, M., Rintala, J.
Number of pages: 8
Pages: 6426-6433
Publication date: Sep 2008
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 99
Issue number: 14
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2008): SJR 1.736 SNIP 2.73
Original language: English
ASJC Scopus subject areas: Agronomy and Crop Science, Food Science, Process Chemistry and Technology, Applied Microbiology and Biotechnology
Keywords: Biofilter, Landfill cover soil, Methane oxidation, Methanotrophs, Tyramide signal amplification-fluorescence in situ hybridization
Source: Scopus
Source ID: 43849105101

Research output: Contribution to journalArticleScientificpeer-review

Anaerobic digestion of grass silage in batch leach bed processes for methane production

Anaerobic digestion of grass silage in batch leach bed reactors, with and without a second stage upflow anaerobic sludge blanket (UASB) reactor, was evaluated. Sixty six percent of the methane potential in grass was obtained within the 55 days solids retention time in the leach bed-UASB process without pH adjustment, whereas in the one-stage leach bed process 20% of the methane potential in grass was extracted. In two-stage operation, adjustment of the pH of influent to the leach bed reactor to 6 with HCl led to inhibition of both hydrolysis/acidogenesis and methanogenesis. In the leach bed-UASB process 39% of the carbohydrates and 58% of the acid soluble lignin were solubilised within the 49 days of operation, whereas Klason lignin was most recalcitrant. The methane potential of the digestates varied from 0.141 to 0.204 m3 CH4 kg-1 added volatile solids.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Jyväskylän yliopisto, University of Jyväskylä
Contributors: Lehtomäki, A., Huttunen, S., Lehtinen, T. M., Rintala, J. A.
Number of pages: 12
Pages: 3267-3278
Publication date: May 2008
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 99
Issue number: 8
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2008): SJR 1.736 SNIP 2.73
Original language: English
ASJC Scopus subject areas: Agronomy and Crop Science, Food Science, Process Chemistry and Technology, Applied Microbiology and Biotechnology
Keywords: Anaerobic digestion, Energy crop, Leach bed, Methane production, UASB
Source: Scopus
Source ID: 38849145183

Research output: Contribution to journalArticleScientificpeer-review

Leachate and gaseous emissions from initial phases of landfilling mechanically and mechanically-biologically treated municipal solid waste residuals

In this study, the behaviour, and leachate and gaseous emissions during the initial phases of landfilling mechanically (M) and mechanically-biologically (MB) treated municipal solid waste residuals in northern climatic conditions was compared using two landfill lysimeters (112 m3). The results demonstrate that the strong acid phase of M residuals degradation lasts at least 2 years, while in the MB residuals the acid phase lasts only a few months. The SCOD and NH4-N concentrations varied 20-100 g/l and 600-1800 mg/l in M leachate and 1-4 g/l and 100-400 mg/l in MB leachate, respectively. The leaching of SCOD was approximately 40-fold (24.2 and 0.6 kg/t TS) and leaching of NH4-N approximately 5-fold (356 and 60 g/t TS) from the M than MB residuals; thus the effect of biological stabilisation was more marked on the leaching of SCOD than of NH4-N. Moreover gas (methane, carbon dioxide and nitrous oxide) emissions were several-fold higher from the M than MB residuals.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Jyväskylän yliopisto, Matti Ettala Ltd., University of Jyväskylä
Contributors: Sormunen, K., Einola, J., Ettala, M., Rintala, J.
Number of pages: 11
Pages: 2399-2409
Publication date: May 2008
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 99
Issue number: 7
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2008): SJR 1.736 SNIP 2.73
Original language: English
ASJC Scopus subject areas: Agronomy and Crop Science, Food Science, Process Chemistry and Technology, Applied Microbiology and Biotechnology
Keywords: Landfill, Mechanical-biological, Methane, Nitrogen, Organic matter
Source: Scopus
Source ID: 38849165441

Research output: Contribution to journalArticleScientificpeer-review

Effects of solid-liquid separation on recovering residual methane and nitrogen from digested dairy cow manure

The feasibility of optimizing methane and nitrogen recovery of samples obtained from farm biogas digester (35 °C) and post-storage tank (where digested material is stored for 9-12 months) was studied by separating the materials into different fractions using 2, 1, 0.5 and 0.25 mm sieves. Mass-balances revealed that digested material mainly consists of <0.25 mm (60-69%) and >2 mm (18-27%) fractions, while fractions between 2 and 0.25 mm made the rest. Incubation of solid fractions >0.25 mm of digester material at 35 °C resulted in specific methane yields of 0.060-0.085 m3 kg-1 volatile solids (VS) during initial 30-50 d and 0.16-0.18 m3 kg-1 VS at the end of 340 d incubation. Similarly, fractions >0.25 mm of post-storage tank material produced 0.055-0.092 m3 kg-1 VS and 0.13-0.16 m3 kg-1 VS of methane after 30-50 d and after 250 d, respectively. Methane yields for fractions <0.25 mm of post-storage tank was 0.03 m3 kg-1 VS after 30-50 d and 0.05 m3 kg-1 VS after 250 d compared to 0.20 m3 kg-1 VS and 0.41 m3 kg-1 VS, respectively for the same fraction of digester material. Separation of digested cow manure into solids and liquid fractions to recover methane may be feasible only for post-storage tank material and not for digester material. Nitrogen management would not be feasible with neither material as total nitrogen and ammonium-nitrogen concentrations were equally distributed among the segregated fractions.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Jyväskylän yliopisto, University of Jyväskylä
Contributors: Kaparaju, P. L. N., Rintala, J. A.
Number of pages: 8
Pages: 120-127
Publication date: Jan 2008
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 99
Issue number: 1
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2008): SJR 1.736 SNIP 2.73
Original language: English
ASJC Scopus subject areas: Agronomy and Crop Science, Food Science, Process Chemistry and Technology, Applied Microbiology and Biotechnology, Bioengineering, Environmental Engineering, Waste Management and Disposal
Keywords: Anaerobic digestion, Digested material, Farm-scale digester, Fractionation, Methane, Post-storage tank
Source: Scopus
Source ID: 34848884581

Research output: Contribution to journalArticleScientificpeer-review

Anaerobic on-site treatment of kitchen waste in combination with black water in UASB-septic tanks at low temperatures

Anaerobic on-site treatment of a mixture of black water and kitchen waste (BWKW) was studied using two-phased upflow anaerobic sludge blanket (UASB) septic tanks at the low temperatures of 20 and 10 °C. Black water (BW) was also treated alone as reference. The two-phased UASB-septic tanks removed over 95% of total suspended solids (TSS) and 90% of total chemical oxygen demand (CODt) from both BWKW (effluent CODt 171-199 mg/l) and BW (effluent CODt 92-100 mg/l). Also, little dissolved COD (CODdis) was left in the final effluents (BW 48-70 mg/l; BWKW 110-113 mg/l). Part of total nitrogen (Ntot) was removed (BW 18% and BWKW 40%) and especially at 20 °C ammonification was efficient. A two-phased process was required to obtain the high removals with BWKW at 10 °C, while with BW a single-phased process may have sufficed even at 10 °C. BWKW also produced more methane than BW alone. Sludge in phases 1 of BW and BWKW treatment was not completely stabilised after 198 d of operation.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Jyväskylän yliopisto, University of Jyväskylä
Contributors: Luostarinen, S., Rintala, J.
Number of pages: 7
Pages: 1734-1740
Publication date: Jul 2007
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 98
Issue number: 9
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2007): SJR 1.403 SNIP 2.394
Original language: English
ASJC Scopus subject areas: Agronomy and Crop Science, Food Science, Process Chemistry and Technology, Applied Microbiology and Biotechnology
Keywords: Anaerobic wastewater treatment, Black water, Kitchen waste, Low temperature, UASB-septic tank
Source: Scopus
Source ID: 33846677724

Research output: Contribution to journalArticleScientificpeer-review

Hydrolysis rates, methane production and nitrogen solubilisation of grey waste components during anaerobic degradation

Municipal grey waste (i.e. the remaining fraction in municipal waste management systems in which putrescibles (biowaste) and other recyclables (paper, metals, glass) are source-segregated) was manually sorted into six main fractions on the basis of composition and also separated by sieving (100 mm mesh size) into two fractions, oversized and undersized, respectively. In practice, in waste management plant the oversized fraction is (or will be) used to produce refuse-derived fuel and the undersized landfilled after biological stabilisation. The methane yields and nitrogen solubilisation of the grey waste and the different fractions (all studied samples were first milled to 5 mm particle samples) were determined in a 237-day methane production batch assay and in a water elution test, respectively. The grey waste was found to contained remnants of putrescibles and also a high amount of other biodegradable waste, including packaging, cartons and cardboard, newsprint, textiles and diapers. These waste fractions comprised 41%-w/w of the grey waste and produced 40-210 m3 methane (total solids (TS))-1 and less than 0.01 gNH4-NkgTS-1 added except diapers which produced 9.8 gNH4-N kgTS-1 added in the batch assays. In the case of the two sieved fractions and on mass bases, most of the methane originated from the oversized fraction, whereas most of the NH4-N was solublised from the undersized fraction. The first-order kinetic model described rather well the degradation of each grey waste fraction and component, showing the different components to be in the range 0.021-0.058 d-1, which was around one-sixth of the values reported for the source-segregated putrescible fraction of MSW.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: University of Jyväskylä, Jyväskylän yliopisto, Russian Academy of Sciences
Contributors: Jokela, J. P. Y., Vavilin, V. A., Rintala, J. A.
Number of pages: 8
Pages: 501-508
Publication date: Mar 2005
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 96
Issue number: 4
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2005): SJR 1.278 SNIP 1.98
Original language: English
ASJC Scopus subject areas: Agronomy and Crop Science, Food Science, Process Chemistry and Technology, Applied Microbiology and Biotechnology
Keywords: Anaerobic degradation, Components, Grey waste, Hydrolysis rate, Landfill, Methane, Municipal solid waste, Nitrogen, Solubilisation, Source-segregation
Source: Scopus
Source ID: 7544250470

Research output: Contribution to journalArticleScientificpeer-review

Modeling solid waste decomposition

The hydrolysis rate coefficients of sorted municipal waste were evaluated from the biochemical methane potential tests using non-linear regression. A distributed mathematical model of anaerobic digestion of rich (food) and lean (non-food) solid wastes with greatly different rates of polymer hydrolysis/acidogenesis was developed to describe the balance between the rates of hydrolysis/acidogenesis and methanogenesis. The model was calibrated using previously published experimental data [Biores. Technol. 52 (1995) 245] obtained upon various initial food waste loadings. Simulations of one- and two-stage digestion systems were carried out. The results showed that initial spatial separation of food waste and inoculum enhances methane production and waste degradation in a one-stage solid-bed digester at high waste loading. A negative effect of vigorously mixing at high waste loading reported in some papers was discussed. It was hypothesized that the initiation methanogenic centers developing in time and expanding in space under minimal mixing conditions might be a key factor for efficient anaerobic conversion of solid waste into methane.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Russian Academy of Sciences, University of Jyväskylä, Jyväskylän yliopisto
Contributors: Vavilin, V. A., Lokshina, L. Y., Jokela, J. P. Y., Rintala, J. A.
Number of pages: 13
Pages: 69-81
Publication date: Aug 2004
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 94
Issue number: 1
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2004): SJR 1.19 SNIP 1.641
Original language: English
ASJC Scopus subject areas: Agronomy and Crop Science, Food Science, Process Chemistry and Technology, Applied Microbiology and Biotechnology
Keywords: Distributed mathematical model, Food waste, Hydrolysis kinetics, Initiation methanogenic centers, One- and two-stage anaerobic digestion, Solids biodegradation
Source: Scopus
Source ID: 1842663304

Research output: Contribution to journalArticleScientificpeer-review

Comparison of laboratory-scale thermophilic biofilm and activated sludge processes integrated with a mesophilic activated sludge process

A combined thermophilic-mesophilic wastewater treatment was studied using a laboratory-scale thermophilic activated sludge process (ASP) followed by mesophilic ASP or a thermophilic suspended carrier biofilm process (SCBP) followed by mesophilic ASP, both systems treating diluted molasses (dilution factor 1:500 corresponding GF/A-filtered COD (CODfilt) of 1900±190 mgl-1). With hydraulic retention times (HRTs) of 12-18 h the thermophilic ASP and thermophilic SCBP removed 60±13% and 62±7% of CODfilt, respectively, with HRT of 8 h the removals were 48±1% and 69±4%. The sludge volume index (SVI) was notably lower in the thermophilic SCBP (measured from suspended sludge) than in the thermophilic ASP. Under the lowest HRT the mesophilic ASP gave better performance (as SVI, CODfilt, and CODtot removals) after the thermophilic SCBP than after the thermophilic ASP. Measured sludge yields were low (less than 0.1 kg suspended solids (SS) kg CODfilt removed -1) in all processes. Both thermophilic treatments removed 80-85% of soluble COD (CODsol) whereas suspended COD (CODsusp) and colloidal COD (CODcol) were increased. Both mesophilic post-treatments removed all CODcol and most of the CODsusp from the thermophilic effluents. In conclusion, combined thermophilic-mesophilic treatment appeared to be easily operable and produced high effluent quality.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: Jyväskylän yliopisto, University of Jyväskylä
Contributors: Suvilampi, J., Lehtomäki, A., Rintala, J.
Number of pages: 8
Pages: 207-214
Publication date: Jul 2003
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 88
Issue number: 3
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2003): SJR 0.942 SNIP 1.677
Original language: English
ASJC Scopus subject areas: Agronomy and Crop Science, Food Science, Process Chemistry and Technology, Applied Microbiology and Biotechnology
Keywords: Activated sludge process, Combined treatment, Mesophilic, Suspended carrier biofilm process, Thermophilic
Source: Scopus
Source ID: 0037411631

Research output: Contribution to journalArticleScientificpeer-review

Anaerobic digestion of organic solid poultry slaughterhouse waste - A review

This work reviews the potential of anaerobic digestion for material recovery and energy production from poultry slaughtering by-products and wastes. First, we describe and quantify organic solid by-products and wastes produced in poultry farming and poultry slaughterhouses and discuss their recovery and disposal options. Then we review certain fundamental aspects of anaerobic digestion considered important for the digestion of solid slaughterhouse wastes. Finally, we present an overview of the future potential and current experience of the anaerobic digestion treatment of these materials.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: University of Jyväskylä, Jyväskylän yliopisto
Contributors: Salminen, E., Rintala, J.
Number of pages: 14
Pages: 13-26
Publication date: 2002
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 83
Issue number: 1
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2002): SJR 0.868 SNIP 1.278
Original language: English
ASJC Scopus subject areas: Agronomy and Crop Science, Food Science, Process Chemistry and Technology, Applied Microbiology and Biotechnology
Keywords: Ammonia, Anaerobic digestion, Inhibition, Long-chain fatty acids, Nutrients recovery, Renewable energy, Solid poultry slaughterhouse waste
Source: Scopus
Source ID: 0036158732

Research output: Contribution to journalArticleScientificpeer-review

Anaerobically digested poultry slaughterhouse wastes as fertiliser in agriculture

Chemical and physical analysis, 27-d plant growth assays with carrot (Daucus carota) and Chinese cabbage (Brassica campestris var. chinensis), and 5-d phytotoxicity assays with Chinese cabbage and perennial ryegrass (Lolium perenne) were used to investigate the suitability of anaerobically digested poultry slaughterhouse waste for fertiliser in agriculture and the effect of aerobic post-treatment on the properties of the digested material.The digested material appeared to be rich in nitrogen. In 27-d assays with digested material as nitrogen source, carrots grew almost as well as those fertilised with a commercial mineral fertiliser used as reference, whereas, the growth of Chinese cabbage was inhibited. In further 5-d phytotoxicity assays, the digested material inhibited the germination and root growth of ryegrass and Chinese cabbage, apparently because of organic acids present in it. Aerobic post-treatment of the material reduced its phytotoxicity but, probably due to the volatilisation of ammonia, resulted in loss of nitrogen.

General information

Publication status: Published
MoE publication type: A1 Journal article-refereed
Organisations: University of Jyväskylä, Jyväskylän yliopisto
Contributors: Salminen, E., Rintala, J., Härkönen, J., Kuitunen, M., Högmander, H., Oikari, A.
Number of pages: 8
Pages: 81-88
Publication date: 2001
Peer-reviewed: Yes

Publication information

Journal: Bioresource Technology
Volume: 78
Issue number: 1
ISSN (Print): 0960-8524
Ratings: 
  • Scopus rating (2001): SJR 0.537 SNIP 1.192
Original language: English
ASJC Scopus subject areas: Agronomy and Crop Science, Food Science, Process Chemistry and Technology, Applied Microbiology and Biotechnology
Keywords: Aerobic post-treatment, Ammonia, Anaerobically digested material, Organic acids, Phytotoxicity assays, Plant growth assays, Poultry slaughterhouse waste
Source: Scopus
Source ID: 0035142679

Research output: Contribution to journalArticleScientificpeer-review