High-rate ferric sulfate generation by aLeptospirillum ferriphilum-dominated biofilm and the role of jarosite in biomass retainment in a fluidized-bed reactor

2004 ◽  
Vol 85 (7) ◽  
pp. 697-705 ◽  
Author(s):  
P�ivi H.-M. Kinnunen ◽  
Jaakko A. Puhakka
Keyword(s):  
Fluidized Bed ◽  
Fluidized Bed Reactor ◽  
Ferric Sulfate ◽  
High Rate

Study of the Role of Small Additions of Zr in the CVD- FBR Aluminization Process

2009 ◽  
Vol 289-292 ◽  
pp. 293-300
Author(s):  
L. Sánchez ◽  
F.J. Bolívar ◽  
M.P. Hierro ◽  
F.J. Pérez
Keyword(s):  
Fluidized Bed ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Fluidized Bed Reactor ◽  
Iron Aluminide ◽  
Martensitic Steels ◽  
Aluminide Coatings ◽  
Deposition Parameters ◽  
Zirconium Powder

In this work, iron aluminide coatings were developed by Chemical Vapor Deposition in Fluidized Bed Reactor (CVD-FBR) on ferritic-martensitic steels. Small additions of zirconium powder were introduced in the fluidized bed; as a consequence, the obtained coatings are thicker than that without zirconium additions. When Zr powders are added in the fluidized bed, the deposition atmosphere drastically changes, leading to increase the deposition rate. Thermodynamic calculations were carried out to simulate the modifications in the CVD atmosphere in the Al/Zr deposition system in comparison to the single aluminization. In order to optimize the conditions of the deposition, parameters such as temperature and concentration of zirconium introduced into the bed were evaluated and compared with the results obtained for the single aluminum deposition.

scholarly journals Role of precursor chemistry in the direct fluorination to form titanium based conversion anodes for lithium ion batteries

RSC Advances ◽  
2015 ◽  
Vol 5 (108) ◽  
pp. 88876-88885 ◽  
Author(s):  
Jonathan M. Powell ◽  
Jamie Adcock ◽  
Sheng Dai ◽  
Gabriel M. Veith ◽  
Craig A. Bridges
Keyword(s):  
Lithium Ion Batteries ◽  
Fluidized Bed ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Fluidized Bed Reactor ◽  
Precursor Chemistry ◽  
Direct Fluorination

An effective approach to increasing the reversible specific capacity of TiOF2 conversion electrodes is presented. The capacity increased greatly when the precursor was partially reduced before direct fluorination in a fluidized bed reactor.

Aerobic and Anaerobic Biotransformations and Treatment of Chlorinated Pulp Bleach Waste Constituents

1994 ◽  
Vol 29 (5-6) ◽  
pp. 73-80 ◽  
Author(s):  
Jaakko A. Puhakka ◽  
Päivi M. Mäkinen ◽  
Margareta Lundin ◽  
John F. Ferguson
Keyword(s):  
Fluidized Bed ◽  
Continuous Flow ◽  
Fluidized Bed Reactor ◽  
High Rate ◽  
Fluidized Bed Reactors ◽  
Chlorinated Phenols ◽  
Anaerobic Fluidized Bed Reactor ◽  
Inorganic Chloride ◽  
Aerobic And Anaerobic ◽  
Complete Dechlorination

Biotransformations and treatment of several chlorinated, hydroxylated and methoxylated monoaromatic compounds were studied in batch bottle bioassays and continuous-flow fluidized-bed reactors. With the aerobic enrichment, polychlorinated phenols were biodegraded with simultaneous release of inorganic chloride in amounts equal to mineralization stoichiometrics. Aerobic removal of 4,5-dichlorocatechol and 4,5- dichlorovanillin were associated with the release of inorganic chlorine. The aerobic enrichment showed no activity against mono- or di-O-methylated phenols. With the anaerobic enrichment, reductive transformations of these compounds were observed. These transformations included reductive dechlorinations, de-O-methylations and dehydroxylations. High-rate operation of an aerobic fluidized-bed reactor resulted in over 99.7% biodégradation of polychlorophenols. In the anaerobic fluidized-bed reactor, over 95% removal of chlorophenols with no apparent accumulation of lower chlorinated phenols indicated complete dechlorination.

High-rate autotrophic denitrification in a fluidized-bed reactor at psychrophilic temperatures

2017 ◽  
Vol 313 ◽  
pp. 591-598 ◽  
Author(s):  
Francesco Di Capua ◽  
Ivana Milone ◽  
Aino-Maija Lakaniemi ◽  
Piet N.L. Lens ◽  
Giovanni Esposito
Keyword(s):  
Fluidized Bed ◽  
Fluidized Bed Reactor ◽  
High Rate ◽  
Autotrophic Denitrification

High-Rate Fluidized-Bed Ferric Sulfate Generation for Hydrometallurgical Applications

2007 ◽  
pp. 54-57
Author(s):  
Jaakko A. Puhakka ◽  
Päivi H.M. Kinnunen ◽  
Tuomas van der Meer ◽  
Bestamin Özkaya ◽  
Erkan Sahinkaya ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Ferric Sulfate ◽  
High Rate

High-rate thiosulfate-driven denitrification at pH lower than 5 in fluidized-bed reactor

2017 ◽  
Vol 310 ◽  
pp. 282-291 ◽  
Author(s):  
Francesco Di Capua ◽  
Aino-Maija Lakaniemi ◽  
Jaakko A. Puhakka ◽  
Piet N.L. Lens ◽  
Giovanni Esposito
Keyword(s):  
Fluidized Bed ◽  
Fluidized Bed Reactor ◽  
High Rate

scholarly journals High nitrification rate at low pH in a fluidized bed reactor with chalk as the biofilm carrier

2004 ◽  
Vol 49 (11-12) ◽  
pp. 99-105 ◽  
Author(s):  
S. Tarre ◽  
M. Beliavski ◽  
N. Denekamp ◽  
A. Gieseke ◽  
D. de Beer ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Bacterial Species ◽  
Fluidized Bed Reactor ◽  
Low Ph ◽  
High Rate ◽  
Nitrifying Bacteria ◽  
Nitrification Rate ◽  
Reactor Performance ◽  
Biofilm Carrier ◽  
Nitrosomonas Oligotropha

A typical steady state bulk pH of about 5 was established in a nitrifying fluidized bed with chalk as the only buffer agent. In spite of the low pH, high rate nitrification was observed with the nitrification kinetic parameters in the chalk reactor similar to those of biological reactors operating at pH>7. Various methods were used to determine the reasons for high rate nitrification at such low pH including (i) determination of bacterial species, (ii) microsensor measurements in the biofilm, and (iii) comparison of nitrification performance at low pH with a non-chalk fluidized bed reactor. Fluorescence in situ hybridization (FISH) using existing 16S rRNA-targeted oligonucleotide probes showed common nitrifying bacteria in the low pH chalk reactor. The prevalent nitrifying bacteria were identified in the Nitrosomonas oligotropha, Nitrosomonas europeae/eutropha, Nitrosospira and Nitrospira related groups, all well known nitrifiers. Microelectrode measurements showed that the pH in the biofilm was low and similar to that of the bulk pH. Finally, reactor performance using a non-chalk biofilm carrier (sintered glass) with the same bacterial inoculum also showed high rate nitrification below pH 5. The results suggest that inhibition of nitrification at low pH is highly overestimated.

High-Rate Fluidized-Bed Ferric Sulfate Generation for Hydrometallurgical Applications

2007 ◽  
Vol 20-21 ◽  
pp. 54-57 ◽  
Author(s):  
Jaakko A. Puhakka ◽  
Päivi H.M. Kinnunen ◽  
Tuomas van der Meer ◽  
Bestamin Özkaya ◽  
Erkan Sahinkaya ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Iron Oxidation ◽  
Heap Leaching ◽  
Ferric Sulfate ◽  
High Rate ◽  
Waste Streams ◽  
Oxidation Rates ◽  
Sulfate Production ◽  
Heap Leach ◽  
Carrier Materials

An overview is presented of a multi-year research effort on developing high-rate fluidized-bed bioprocesses for ferric sulfate production to be used as a unit process in various hydrometallurgical applications including indirect tank leaching of ore concentrates, regeneration of heap leach liquors and control of iron containing acidic mine wastewater. Iron oxidation rates of over 26 kg m-3 h-1 were achieved at hydraulic retention times of less than 1 h at 37 °C. Oxygen supply became the rate-limiting factor even with 99.5% dioxygen aeration. Fe2+ oxidation proceeded at pH below 1 even in the presence of 60 g Fe3+ L-1 allowing the regeneration of concentrated ferric sulphate solutions required in indirect tank leaching of sulfidic ore concentrate applications. Of several tested FBR carrier materials activated carbon was the most suitable based on its availability, long-term durability and the achieved high iron oxidation rates. Jarosite precipitates accumulating to the top of the inert carrier materials played an important role in the FBR biomass retainment. For regeneration of synthetic and actual sulfidic ore heap leaching liquors, a gravity settler was installed in the recycle line of the FBR. The system produced iron precipitates with good settling characteristics and settling tank effluent with low turbidity and suspended solids concentrations. These results revealed the potential of FBR process in both heap leach liquor regeneration and controlling the iron containing waste streams. The PCR-DGGE-partial seguencing of the 16S rRNA gene protocol revealed that the FBR culture at 25-37 °C remained dominated by Leptospirillum ferriphilum over a range of operational conditions studied over the years. A modeling approach for managing Fe3+ production by FBR in combination with heap leaching was based on an artificial neural network-back propagation algorithm (ANN-HEAP) and resulted in excellent match between the measured and the predicted concentrations. High-rate fluidized-bed iron oxidation is amenable to regeneration of tank and heap leaching solutions as well as controlling iron containing waste streams.

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