The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Miao Chen - One of the best experts on this subject based on the ideXlab platform.
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bioleaching of low grade waste printed circuit boards by mixed fungal culture and its community structure analysis
Resources Conservation and Recycling, 2018Co-Authors: Mingchen Xia, Peng Bao, Yuandong Liu, Miao Chen, Ajuan Liu, Mingwei Wang, Li ShenAbstract:Abstract Biohydrometallurgy is generally regarded as a “green technology” for the recycling of electronic waste. The present work was aimed at studying the feasibility of extracting metals from waste printed circuit boards (PCBs) by mixed fungal cultures in the stirred tank reactor. By prior step-wise bioleaching experiments in the flasks, the tolerance of one group of mixed fungal cultures to waste PCBs was brought up to 8% (w/v) pulp density. Thereafter this mixed culture was subjected to further leaching process at the same pulp density in scale-up bioleaching system. The results showed that 56.1 ± 0.69% of Cu, 15.7 ± 0.87% of Al, 20.5 ± 0.78% of Pb, 49.5 ± 0.38% of Zn and 8.1 ± 0.34% of Sn were extracted finally. Furthermore, scanning electron microscopic observation combining with Energy dispersive analysis of x-ray revealed that mycelium could interact with PCBs particles by enwrapping them and adsorbing polymer matrix and metal ions from PCBs. Fourier transform infrared spectroscopy analysis further proved these toxic components destroyed key functional groups of mycelium and then interfered bioleaching efficiency. Community structure analysis revealed that Purpureocillium lilacinum and Aspergillus niger were the two dominated fungal species with abundance of 71.9% and 27.9% at the end of bioleaching process, respectively.
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bacterial extracellular polysaccharides involved in biofilm formation
Molecules, 2009Co-Authors: Barbara Vu, Miao Chen, Russell J Crawford, Elena P IvanovaAbstract:Extracellular polymeric substances (EPS) produced by microorganisms are a complex mixture of biopolymers primarily consisting of polysaccharides, as well as proteins, nucleic acids, lipids and humic substances. EPS make up the intercellular space of microbial aggregates and form the structure and architecture of the biofilm matrix. The key functions of EPS comprise the mediation of the initial attachment of cells to different substrata and protection against environmental stress and dehydration. The aim of this review is to present a summary of the current status of the research into the role of EPS in bacterial attachment followed by biofilm formation. The latter has a profound impact on an array of biomedical, biotechnology and industrial fields including pharmaceutical and surgical applications, food engineering, bioremediation and Biohydrometallurgy. The diverse structural variations of EPS produced by bacteria of different taxonomic lineages, together with examples of biotechnological applications, are discussed. Finally, a range of novel techniques that can be used in studies involving biofilm-specific polysaccharides is discussed.
Yuandong Liu - One of the best experts on this subject based on the ideXlab platform.
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bioleaching of low grade waste printed circuit boards by mixed fungal culture and its community structure analysis
Resources Conservation and Recycling, 2018Co-Authors: Mingchen Xia, Peng Bao, Yuandong Liu, Miao Chen, Ajuan Liu, Mingwei Wang, Li ShenAbstract:Abstract Biohydrometallurgy is generally regarded as a “green technology” for the recycling of electronic waste. The present work was aimed at studying the feasibility of extracting metals from waste printed circuit boards (PCBs) by mixed fungal cultures in the stirred tank reactor. By prior step-wise bioleaching experiments in the flasks, the tolerance of one group of mixed fungal cultures to waste PCBs was brought up to 8% (w/v) pulp density. Thereafter this mixed culture was subjected to further leaching process at the same pulp density in scale-up bioleaching system. The results showed that 56.1 ± 0.69% of Cu, 15.7 ± 0.87% of Al, 20.5 ± 0.78% of Pb, 49.5 ± 0.38% of Zn and 8.1 ± 0.34% of Sn were extracted finally. Furthermore, scanning electron microscopic observation combining with Energy dispersive analysis of x-ray revealed that mycelium could interact with PCBs particles by enwrapping them and adsorbing polymer matrix and metal ions from PCBs. Fourier transform infrared spectroscopy analysis further proved these toxic components destroyed key functional groups of mycelium and then interfered bioleaching efficiency. Community structure analysis revealed that Purpureocillium lilacinum and Aspergillus niger were the two dominated fungal species with abundance of 71.9% and 27.9% at the end of bioleaching process, respectively.
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Isolation and identification of Penicillium chrysogenum strain Y5 and its copper extraction characterization from waste printed circuit boards
Journal of bioscience and bioengineering, 2018Co-Authors: Mingchen Xia, Peng Bao, Liu Ajuan, Shishi Zhang, Tangjian Peng, Yu Runlan, Li Jiaokun, Yuandong LiuAbstract:Biohydrometallurgy is generally considered as a green technology for the recycling of industrial solid waste. In this study, an indigenous fungal strain named Y5 with the ability of high-yielding organic acids was isolated and applied in bioleaching of waste printed circuit boards (PCBs). The strain Y5 was identified as Penicillium chrysogenum by morphological and molecular identification. Meanwhile, we investigated that an optimal set of culturing conditions for the fungal growth and acids secretion was 15 g/L glucose with initial pH 5.0, temperature 25°C and shaking speed 120 rpm in shaken flasks culture. Moreover, three bioleaching processes such as one-step, two-step and spent medium processes were conducted to extract copper from waste PCBs. Spent medium bioleaching showed higher copper extraction percentage and it was 47% under 5%(w/v) pulp density. Transmission electron microscope (TEM) observation combining with energy dispersive analysis of X-rays (EDAX) showed that the leached metal ions did not obviously damage the hypha cells. All above results indicated that P.chrysogenum strain Y5 has the tolerance to metal ions, suggesting its potential in recycling of metals from waste PCBs in industry.
Mingchen Xia - One of the best experts on this subject based on the ideXlab platform.
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bioleaching of low grade waste printed circuit boards by mixed fungal culture and its community structure analysis
Resources Conservation and Recycling, 2018Co-Authors: Mingchen Xia, Peng Bao, Yuandong Liu, Miao Chen, Ajuan Liu, Mingwei Wang, Li ShenAbstract:Abstract Biohydrometallurgy is generally regarded as a “green technology” for the recycling of electronic waste. The present work was aimed at studying the feasibility of extracting metals from waste printed circuit boards (PCBs) by mixed fungal cultures in the stirred tank reactor. By prior step-wise bioleaching experiments in the flasks, the tolerance of one group of mixed fungal cultures to waste PCBs was brought up to 8% (w/v) pulp density. Thereafter this mixed culture was subjected to further leaching process at the same pulp density in scale-up bioleaching system. The results showed that 56.1 ± 0.69% of Cu, 15.7 ± 0.87% of Al, 20.5 ± 0.78% of Pb, 49.5 ± 0.38% of Zn and 8.1 ± 0.34% of Sn were extracted finally. Furthermore, scanning electron microscopic observation combining with Energy dispersive analysis of x-ray revealed that mycelium could interact with PCBs particles by enwrapping them and adsorbing polymer matrix and metal ions from PCBs. Fourier transform infrared spectroscopy analysis further proved these toxic components destroyed key functional groups of mycelium and then interfered bioleaching efficiency. Community structure analysis revealed that Purpureocillium lilacinum and Aspergillus niger were the two dominated fungal species with abundance of 71.9% and 27.9% at the end of bioleaching process, respectively.
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Isolation and identification of Penicillium chrysogenum strain Y5 and its copper extraction characterization from waste printed circuit boards
Journal of bioscience and bioengineering, 2018Co-Authors: Mingchen Xia, Peng Bao, Liu Ajuan, Shishi Zhang, Tangjian Peng, Yu Runlan, Li Jiaokun, Yuandong LiuAbstract:Biohydrometallurgy is generally considered as a green technology for the recycling of industrial solid waste. In this study, an indigenous fungal strain named Y5 with the ability of high-yielding organic acids was isolated and applied in bioleaching of waste printed circuit boards (PCBs). The strain Y5 was identified as Penicillium chrysogenum by morphological and molecular identification. Meanwhile, we investigated that an optimal set of culturing conditions for the fungal growth and acids secretion was 15 g/L glucose with initial pH 5.0, temperature 25°C and shaking speed 120 rpm in shaken flasks culture. Moreover, three bioleaching processes such as one-step, two-step and spent medium processes were conducted to extract copper from waste PCBs. Spent medium bioleaching showed higher copper extraction percentage and it was 47% under 5%(w/v) pulp density. Transmission electron microscope (TEM) observation combining with energy dispersive analysis of X-rays (EDAX) showed that the leached metal ions did not obviously damage the hypha cells. All above results indicated that P.chrysogenum strain Y5 has the tolerance to metal ions, suggesting its potential in recycling of metals from waste PCBs in industry.
Horacio J. Thomas - One of the best experts on this subject based on the ideXlab platform.
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Removal of VOCs by catalytic process. A study of MnZnO composites synthesized from waste alkaline and Zn/C batteries
Chemical Engineering Journal, 2017Co-Authors: María V. Gallegos, Miguel A. Peluso, Elisabetta Finocchio, Horacio J. Thomas, Guido Busca, Jorge E. SambethAbstract:Abstract Spent alkaline and zinc-carbon batteries were subjected to a Biohydrometallurgy process, in order to recover manganese and mixed manganese zinc oxides. Two solids were synthesized, one of them prepared by reaction of MnSO 4 and KMnO 4 (MnO x ) and the other obtained by chemical precipitation with NaOH (ZnMnO). The characterization by XRD, TPR, FTIR and XPS revealed the presence of Mn 3+ and Mn 4+ cations in both samples, and the presence of ZnO and Mn-Zn spinels in ZnMnO. The samples were evaluated in the oxidation reaction of ethanol and toluene. The results in the flow reactor showed that ethanol conversion on both catalysts, MnO x and ZnMnO, is rather similar, but toluene conversion is markedly higher on MnO x, due to a greater Mn/Zn ratio and to the absence of a crystallized ZnO phase. The FTIR study demonstrated that ethanol is oxidized to acetaldehyde at low temperature, and to CO 2 and CO at 400 °C. Traces of CH 4 in the gas phase are also detected at high temperature. The formation of ethoxy and acetate groups is observed at the catalyst surface. With respect to toluene oxidation, CO 2 is detected at 300 °C and when the temperature is increased, CO is also observed in the gas phase. The results showed that: (i) the alkaline and Zn-carbon batteries can be recycled as catalysts and (ii) the solids can be used in the catalytic process for VOCs control.
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recovery of manganese oxides from spent alkaline and zinc carbon batteries an application as catalysts for vocs elimination
Waste Management, 2013Co-Authors: Maria Victoria Gallegos, Jorge E. Sambeth, Lorena Falco, Miguel Andres Peluso, Horacio J. ThomasAbstract:Abstract Manganese, in the form of oxide, was recovered from spent alkaline and zinc–carbon batteries employing a Biohydrometallurgy process, using a pilot plant consisting in: an air-lift bioreactor (containing an acid-reducing medium produced by an Acidithiobacillus thiooxidans bacteria immobilized on elemental sulfur); a leaching reactor (were battery powder is mixed with the acid-reducing medium) and a recovery reactor. Two different manganese oxides were recovered from the leachate liquor: one of them by electrolysis (EMO) and the other by a chemical precipitation with KMnO4 solution (CMO). The non-leached solid residue was also studied (RMO). The solids were compared with a MnOx synthesized in our laboratory. The characterization by XRD, FTIR and XPS reveal the presence of Mn2O3 in the EMO and the CMO samples, together with some Mn4+ cations. In the solid not extracted by acidic leaching (RMO) the main phase detected was Mn3O4. The catalytic performance of the oxides was studied in the complete oxidation of ethanol and heptane. Complete conversion of ethanol occurs at 200 °C, while heptane requires more than 400 °C. The CMO has the highest oxide selectivity to CO2. The results show that manganese oxides obtained using spent alkaline and zinc–carbon batteries as raw materials, have an interesting performance as catalysts for elimination of VOCs.
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recovery of manganese oxides from spent alkaline and zinc carbon batteries an application as catalysts for vocs elimination
Waste Management, 2013Co-Authors: Maria Victoria Gallegos, Miguel A. Peluso, Jorge E. Sambeth, Lorena Falco, Horacio J. ThomasAbstract:Highlights: • Manganese oxides were synthesized using spent batteries as raw materials. • Spent alkaline and zinc–carbon size AA batteries were used. • A biohydrometallurgical process was employed to bio-lixiviate batteries. • Manganese oxides were active in the oxidation of VOCs (ethanol and heptane). - Abstract: Manganese, in the form of oxide, was recovered from spent alkaline and zinc–carbon batteries employing a Biohydrometallurgy process, using a pilot plant consisting in: an air-lift bioreactor (containing an acid-reducing medium produced by an Acidithiobacillus thiooxidans bacteria immobilized on elemental sulfur); a leaching reactor (were battery powder is mixed with the acid-reducing medium) and a recovery reactor. Two different manganese oxides were recovered from the leachate liquor: one of them by electrolysis (EMO) and the other by a chemical precipitation with KMnO{sub 4} solution (CMO). The non-leached solid residue was also studied (RMO). The solids were compared with a MnO{sub x} synthesized in our laboratory. The characterization by XRD, FTIR and XPS reveal the presence of Mn{sub 2}O{sub 3} in the EMO and the CMO samples, together with some Mn{sup 4+} cations. In the solid not extracted by acidic leaching (RMO) the main phase detected was Mn{sub 3}O{sub 4}. The catalytic performance of themore » oxides was studied in the complete oxidation of ethanol and heptane. Complete conversion of ethanol occurs at 200 °C, while heptane requires more than 400 °C. The CMO has the highest oxide selectivity to CO{sub 2}. The results show that manganese oxides obtained using spent alkaline and zinc–carbon batteries as raw materials, have an interesting performance as catalysts for elimination of VOCs.« less
Li Shen - One of the best experts on this subject based on the ideXlab platform.
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bioleaching of low grade waste printed circuit boards by mixed fungal culture and its community structure analysis
Resources Conservation and Recycling, 2018Co-Authors: Mingchen Xia, Peng Bao, Yuandong Liu, Miao Chen, Ajuan Liu, Mingwei Wang, Li ShenAbstract:Abstract Biohydrometallurgy is generally regarded as a “green technology” for the recycling of electronic waste. The present work was aimed at studying the feasibility of extracting metals from waste printed circuit boards (PCBs) by mixed fungal cultures in the stirred tank reactor. By prior step-wise bioleaching experiments in the flasks, the tolerance of one group of mixed fungal cultures to waste PCBs was brought up to 8% (w/v) pulp density. Thereafter this mixed culture was subjected to further leaching process at the same pulp density in scale-up bioleaching system. The results showed that 56.1 ± 0.69% of Cu, 15.7 ± 0.87% of Al, 20.5 ± 0.78% of Pb, 49.5 ± 0.38% of Zn and 8.1 ± 0.34% of Sn were extracted finally. Furthermore, scanning electron microscopic observation combining with Energy dispersive analysis of x-ray revealed that mycelium could interact with PCBs particles by enwrapping them and adsorbing polymer matrix and metal ions from PCBs. Fourier transform infrared spectroscopy analysis further proved these toxic components destroyed key functional groups of mycelium and then interfered bioleaching efficiency. Community structure analysis revealed that Purpureocillium lilacinum and Aspergillus niger were the two dominated fungal species with abundance of 71.9% and 27.9% at the end of bioleaching process, respectively.