Hernoux-Villiere A.,Kokkola University Consortium Chydenius |
Hernoux-Villiere A.,University of Savoy |
Lassi U.,Kokkola University Consortium Chydenius |
Lassi U.,University of Oulu |
Leveque J.-M.,University of Savoy
Ultrasonics Sonochemistry | Year: 2013
An advanced dual frequency ultrasonic coaxial reactor enabling simultaneously low and high frequencies irradiating in the same direction was developed to focus both mechanical and chemical effects on a concentrated area. The prototype was straightforward employed for the conversion of a starch-based industrial waste into sugars. © 2013 Elsevier B.V. All rights reserved. Source
The high energy density of lithium-ion (Li-ion) batteries make them a popular energy storage technology, especially in mobile applications such as personal electronics and electric cars. However, the materials currently used in Li-ion batteries are expensive, while many of them, like lithium cobalt oxide, are also difficult to handle and dispose of. What is more, batteries using these materials have relatively short lifetimes. These shortcomings have led scientists to develop novel materials for next generation Li-ion batteries: two promising electrode materials are lithium titanate and lithium iron phosphate. The materials are readily available, safe to use, and easy to dispose of or recycle. Most importantly, batteries manufactured using these materials have significantly longer cycle and calendar lifetimes compared to current battery technologies. However, these new materials are currently hampered by their low electrical conductivity. Scientists at the University of Eastern Finland (UEF) in Kuopio have now come up with a potential solution to this low conductivity problem, which is reported in a paper in the Journal of Alloys and Compounds. "The electric conductivity problem can be solved by producing nanosized, high surface area crystalline materials, or by modifying the material composition with highly conductive dopants, " explains Tommi Karhunen, a researcher in the UEF Fine Particle and Aerosol Technology Laboratory. "We have succeeded in doing both for lithium titanate in a simple, one-step gas phase process developed here at the UEF Fine Particle and Aerosol Technology Laboratory." "The electrochemical performance of Li-ion batteries made out of the above mentioned material is very promising," says Jorma Jokiniemi, director of the UEF Fine Particle and Aerosol Technology Laboratory. "The electrochemical properties were studied in collaboration with Professor Ulla Lassi's group from Kokkola University Consortium Chydenius. The most important applications lie in batteries featuring, for example, fast charging required for electric buses, or high power needed for hybrid and electric vehicles." This story is adapted from material from the University of Eastern Finland, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.
Kilpimaa S.,University of Oulu |
Runtti H.,University of Oulu |
Kangas T.,University of Oulu |
Lassi U.,University of Oulu |
And 2 more authors.
Chemical Engineering Research and Design | Year: 2014
Carbon residue is a by-product from the biomass gasification process in which heat and power are generated. In this study, carbon residue was chemically activated and the effect of this activation process on the adsorption properties was investigated. A chemically activated carbon residue was used as an adsorbent for the removal of phosphate and nitrate in an aqueous solution. The general idea is that the carbon residue could first be used as a low cost adsorbent for phosphate and nitrate ions removal, e.g. from wastewaters, and after that it could be used as a nitrogen and phosphorus rich forest fertiliser.Based on the results, the most effective pH value for phosphate removal was 6, 4 and 6 for activated carbon residue, carbon residue and activated carbon respectively. Optimum pH value for nitrate removal was 6 for activated carbon residue and carbon residue, and 4 for activated carbon. The optimum concentrations for the initial phosphate solutions for activated carbon residue, carbon residue and activated carbon were 25, 50 and 25mgL-1 respectively. For nitrate, the optimal concentration was 25mgL-1 for all adsorbents. Phosphate and nitrate adsorption kinetics were well fitted by the pseudo-second-order kinetic model for all studied adsorbents. Phosphate and nitrate adsorption onto activated carbon residue obey well Langmuir adsorption isotherm. © 2014 The Institution of Chemical Engineers. Source
Tolonen E.-T.,University of Oulu |
Sarpola A.,Oulu Water Alliance Ltd. |
Hu T.,University of Oulu |
Ramo J.,University of Oulu |
And 2 more authors.
Chemosphere | Year: 2014
The aim of this research was to investigate whether by-products from quicklime manufacturing could be used instead of commercial quicklime (CaO) or hydrated lime (Ca(OH)2), which are traditionally used as neutralization chemicals in acid mine drainage treatment. Four by-products were studied and the results were compared with quicklime and hydrated lime. The studied by-products were partly burnt lime stored outdoors, partly burnt lime stored in a silo, kiln dust and a mixture of partly burnt lime stored outdoors and dolomite. Present application options for these by-products are limited and they are largely considered waste. Chemical precipitation experiments were performed with the jar test. All the studied by-products removed over 99% of Al, As, Cd, Co, Cu, Fe, Mn, Ni, Zn and approximately 60% of sulphate from acid mine drainage. However, the neutralization capacity of the by-products and thus the amount of by-product needed as well as the amount of sludge produced varied. The results indicated that two out of the four studied by-products could be used as an alternative to quicklime or hydrated lime for acid mine drainage treatment. © 2014 Elsevier Ltd. Source
Pohjalainen E.,Aalto University |
Rasanen S.,Kokkola University Consortium Chydenius |
Jokinen M.,Aalto University |
Yliniemi K.,Aalto University |
And 7 more authors.
Journal of Power Sources | Year: 2013
Less expensive and greener aqueous electrode preparation processes are essential for the market penetration of lithium ion batteries to mid-scale applications. So far only carboxyl methyl cellulose (CMC) binder has been adopted for industrial use to fabricate carbon electrodes without harmful organic solvents but this process is prone to bacterial growth. In this study a new binder candidate, Acryl S020, is introduced for an aqueous preparation process that has been used for preparing Li4Ti5O 12 electrodes for lithium ion batteries. It is shown that with our water based process electrodes with capacities comparable to those electrodes fabricated with the conventional organic solvent based process with the PVDF binder are obtained. Moreover, our lithium titanate electrodes with the Acryl S020 binder show high capacity retention and they can be operated at sub-zero temperatures. Electrodes were also fabricated with pilot-scale gravure printing and slot-die coating methods and they showed stable cycles lives of 500 cycles. © 2012 Published by Elsevier B.V. All rights reserved. Source