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https://www.readbyqxmd.com/read/28540545/a-novel-bioelectrode-and-anaerobic-sludge-coupled-system-for-p-clnb-degradation-by-magnetite-nanoparticles-addition
#1
Xiangyang Xu, Xinyi Gao, Jie Jin, Julia Vidonish, Liang Zhu
A novel laboratory-scale bioelectrode and anaerobic sludge coupled system was established for the enhancement of p-chloronitrobenzenes (p-ClNB) reductive transformation with addition of magnetite nanoparticles. In this coupled system, the bioelectrodes were supplied with a voltage of 0.8 V and the amount of magnetite nanoparticles was set at 7.4 mL/400 mL. Results showed that high p-ClNB transformation rate of 0.284 h(-1) and high p-chloroaniline (p-ClAn) dechlorination rate of 0.082 h(-1) were achieved in the coupled system at p-ClNB initial concentration of 30 mg L(-1), and p-ClAn is one of the reductive products of p-ClNB...
May 24, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28533514/isolation-and-genomic-characterization-of-a-dehalococcoides-strain-suggests-genomic-rearrangement-during-culture
#2
Masafumi Yohda, Kentaro Ikegami, Yuto Aita, Mizuki Kitajima, Ayane Takechi, Megumi Iwamoto, Tomomi Fukuda, Noriyoshi Tamura, Junji Shibasaki, Seiji Koike, Daisuke Komatsu, Sakari Miyagi, Minoru Nishimura, Yoshihito Uchino, Akino Shiroma, Makiko Shimoji, Hinako Tamotsu, Noriko Ashimine, Misuzu Shinzato, Shun Ohki, Kazuma Nakano, Kuniko Teruya, Kazuhito Satou, Takashi Hirano, Osami Yagi
We have developed and characterized a bacterial consortium that reductively dechlorinates trichloroethene to ethene. Quantitative PCR analysis for the 16S rRNA and reductive dehalogenase genes showed that the consortium is highly enriched with Dehalococcoides spp. that have two vinyl chloride reductive dehalogenase genes, bvcA and vcrA, and a trichloroethene reductive dehalogenase gene, tceA. The metagenome analysis of the consortium by the next generation sequencer SOLiD 3 Plus suggests that a Dehalococcoides sp...
May 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28527388/abiotic-transformation-of-hexabromocyclododecane-by-sulfidated-nanoscale-zerovalent-iron-kinetics-mechanism-and-influencing-factors
#3
Dan Li, Xifen Zhu, Yin Zhong, Weilin Huang, Ping'an Peng
Recent studies showed that sulfidated nanoscale zerovalent iron (S-nZVI) is a better reducing agent than nanoscale zerovalen iron (nZVI) alone for reductive dechlorination of several organic solvents such as trichloroethylene (TCE) due to the catalytic role of iron sulfide (FeS). We measured the rates of transformation of hexabromocyclododecane (HBCD) by S-nZVI and compared them to those by FeS, nZVI, and reduced sulfur species. The results showed that: i) HBCD (20 mg L(-1)) was almost completely transformed by S-nZVI (0...
May 9, 2017: Water Research
https://www.readbyqxmd.com/read/28527381/enantioselectivity-of-haloalkane-dehalogenase-linb-on-the-degradation-of-1-2-dichloropropane-a-qm-mm-study
#4
Xiaowen Tang, Ruiming Zhang, Yanwei Li, Qingzhu Zhang, Wenxing Wang
The hydrolysis dechlorination mechanism of a chiral organochlorinepollutant, 1,2-dichloropropane (DCP), catalyzed by haloalkane dehalogenase LinB has been investigated by using a combined quantum mechanics/molecular mechanics method. LinB was confirmed to be enantioselective towards the catabolism of the racemic mixture. Based on the SN2 nucleophilic substitution mechanism, the dechlorination process was identified as the rate-determining step in LinB-catalyzed degradation of 1,2-dichloropropane, the Boltzmann-weighted average potential barrier of which is 18...
May 12, 2017: Bioorganic Chemistry
https://www.readbyqxmd.com/read/28505481/altered-development-oxidative-stress-and-dna-damage-in-leptodactylus-chaquensis-anura-leptodactylidae-larvae-exposed-to-poultry-litter
#5
L M Curi, P M Peltzer, C Martinuzzi, M A Attademo, S Seib, M F Simoniello, R C Lajmanovich
Poultry litter (PL), which is usually used as organic fertilizer, is a source of nutrients, metals, veterinary pharmaceuticals and bacterial pathogens, which, through runoff, may end up in the nearest aquatic ecosystems. In this study, Leptodactylus chaquensis at different development stages (eggs, larval stages 28 and 31 here referred to as stages I, II and III respectively) were exposed to PL test sediments as follows: 6.25% (T1), 12.5% (T2); 25% (T3); 50% (T4); 75% (T5); 100% PL (T6) and to dechlorinated water as control...
May 11, 2017: Ecotoxicology and Environmental Safety
https://www.readbyqxmd.com/read/28502601/recycling-of-spent-lithium-ion-battery-with-polyvinyl-chloride-by-mechanochemical-process
#6
Meng-Meng Wang, Cong-Cong Zhang, Fu-Shen Zhang
In the present study, cathode materials (C/LiCoO2) of spent lithium-ion batteries (LIBs) and waste polyvinyl chloride (PVC) were co-processed via an innovative mechanochemical method, i.e. LiCoO2/PVC/Fe was co-grinded followed by water-leaching. This procedure generated recoverable LiCl from Li by the dechlorination of PVC and also generated magnetic CoFe4O6 from Co. The effects of different additives (e.g. alkali metals, non-metal oxides, and zero-valent metals) on (i) the conversion rates of Li and Co and (ii) the dechlorination rate of PVC were investigated, and the reaction mechanisms were explored...
May 11, 2017: Waste Management
https://www.readbyqxmd.com/read/28501644/mechanistic-and-computational-studies-of-pcb-151-dechlorination-by-zero-valent-magnesium-for-field-remediation-optimization
#7
Fiona M Zullo, Muqiong Liu, Shengli Zou, Cherie L Yestrebsky
Polychlorinated biphenyls (PCBs) are banned in the U.S. but are persistent in the environment; current regulations provide an urgent need to remediate PCBs in a cost-effective way. In prior work, a novel method of degradation of PCBs via hydrodehalogenation with ball milled zero-valent magnesium and activated carbon showed promising results even with water present in the system. In this research, a detailed study of the byproducts formed in the dechlorination process for PCB 151 (used as an example of hexa-chlorinated PCB) and a study of the mechanism involved in this reaction via density functional theory (DFT) computations are presented...
April 24, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28499177/the-dechlorination-of-pentachlorophenol-under-a-sulfate-and-iron-reduction-co-occurring-anaerobic-environment
#8
Lili Xue, Xi Feng, Yan Xu, Xinfeng Li, Min Zhu, Jianming Xu, Yan He
An anaerobic soil slurry incubation experiment was conducted by controlling different Fe/S mole ratios (1/3, 1/2, 1/1, 2/1, 3/1, 8/1 and the control without sulfate) through the addition of sodium sulfate, to investigate the effect of sulfate and iron reduction on the reductive dechlorination of pentachlorophenol (PCP). Two sequential incubation periods were carried out with the stage I incubation conducted under a low electron donor concentration (0.5 mM lactate) and stage II incubation conducted under increased electron donor supply with lactate at 20 mM...
April 25, 2017: Chemosphere
https://www.readbyqxmd.com/read/28497683/a-kinetic-pathway-towards-high-density-ordered-n-doping-of-epitaxial-graphene-on-cu-111-using-c5ncl5-precursors
#9
Ping Cui, Jin-Ho Choi, Changgan Zeng, Zhenyu Li, Jinlong Yang, Zhenyu Zhang
Pristine graphene possesses high electrical mobility, but its low charge carrier density severely limits its technological significance. Past efforts to increase graphene's carrier density via chemical doping have shown limited successes, accompanied by substantial reductions in the mobility caused by disordered dopants. Here, based on first-principles calculations, we propose to grow graphene on Cu(111) via self-assembly of C5NCl5 molecular precursors to achieve high-density (1/6) and highly ordered nitrogen doping...
May 12, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28494362/transformation-of-carbon-tetrachloride-and-chloroform-by-trichloroethene-respiring-anaerobic-mixed-cultures-and-supernatant
#10
Kyle E Vickstrom, Mohammad F Azizian, Lewis Semprini
Carbon tetrachloride (CT) and chloroform (CF) were transformed in batch reactor experiments conducted with anaerobic dechlorinating cultures and supernatant (ADC + S) harvested from continuous flow reactors. The Evanite (EV) and Victoria/Stanford (VS) cultures, capable of respiring trichloroethene (TCE), 1,2-cis-dichloroethene (cDCE), and vinyl chloride (VC) to ethene (ETH), were grown in continuous flow reactors receiving an influent feed of saturated TCE (10 mM; 60 mEq) and formate (45 mM; 90 mEq) but no CT or CF...
April 29, 2017: Chemosphere
https://www.readbyqxmd.com/read/28488466/the-removal-of-chlorinated-aliphatic-hydrocarbons-from-water-using-reactive-activated-carbon-the-influence-of-synthesis-factors-and-reaction-environments
#11
Zhang Wei, Xiao Ting, Liu Nuo, Ying Weichi
In this work, granular activated carbon composite incorporated with nanoscale zerovalent iron particles (reactive activated carbon, RAC) was synthesized by the liquid phase precipitation method and used to remove chlorinated aliphatic hydrocarbons (CAHs) from water. The influence of synthesis factors, such as base carbon types and annealing treatment temperature, and environmental factors, such as molecular structure of CAHs, common ionic species and natural organic matter, on the removal capacities of RAC for CAHs were investigated...
May 10, 2017: Environmental Technology
https://www.readbyqxmd.com/read/28482655/carbon-and-chlorine-isotope-fractionation-patterns-associated-with-different-engineered-chloroform-transformation-reactions
#12
Clara Torrentó, Jordi Palau, Diana Rodríguez-Fernández, Benjamin Heckel, Armin H Meyer, Cristina Domenech, Monica Rosell, Albert Soler, Martin Elsner, Daniel Hunkeler
To use compound-specific isotope analysis for confidently assessing organic contaminant attenuation in the environment, isotope fractionation patterns associated with different transformation mechanisms must first be explored in laboratory experiments. To deliver this information for the common groundwater contaminant chloroform (CF), this study investigated for the first time both carbon and chlorine isotope fractionation for three different engineered reactions: oxidative C-H bond cleavage using heat-activated persulfate, transformation under alkaline conditions (pH~12) and reductive C-Cl bond cleavage by cast zero-valent iron, Fe(0)...
May 9, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28460326/simultaneous-electrodialytic-removal-of-pah-pcb-tbt-and-heavy-metals-from-sediments
#13
Kristine B Pedersen, Tore Lejon, Pernille E Jensen, Lisbeth M Ottosen
Contaminated sediments are remediated in order to protect human health and the environment, with the additional benefit of using the treated sediments for other activities. Common for many polluted sediments is the contamination with several different pollutants, making remediation challenging with the need of different remedial actions for each pollutant. In this study, electrodialytic remediation (EDR) of sediments was found effective for simultaneous removal of heavy metals and organic pollutants for sediments from Arctic regions - Sisimiut in Greenland and Hammerfest in Norway...
April 28, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/28448880/rapid-green-synthesis-of-gold-nanocatalyst-for-high-efficiency-degradation-of-quinclorac
#14
Guorong Shi, Yulu Li, Gaihong Xi, Qinqin Xu, Zijun He, Yating Liu, Jianhui Zhang, Jun Cai
Porous chemical pretreated Saccharomyces cerevisiae was used as support, stabilizer, and reducing agent for the rapid green synthesis of gold nanocatalyst. Au nanoparticles (Au NPs) were generated through in-situ reduction of the absorbed Au(III) by the reductive functional groups of mannoproteins in yeast cell wall. The obtained spherical mono-dispersed Au NPs have an average particle diameter of 9.99±1.63nm as evidenced by TEM image, and exhibits excellent catalytic activity for the dechlorination of quinclorac to 8-quinoline-carboxylic acid by sodium borohydride...
April 18, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28447779/performance-and-mechanism-of-piezo-catalytic-degradation-of-4-chlorophenol-finding-of-effective-piezo-dechlorination
#15
Shenyu Lan, Jinxi Feng, Ya Xiong, Shuanghong Tian, Shengwei Liu, Lingjun Kong
Piezo-catalysis was first used to degrade a nondye pollutant, 4-chlorophenol (4-CP). In this process, hydrothermally synthesized tetragonal BaTiO3 nano/micrometer-sized particles were used as the piezo-catalyst, and the ultrasonic irradiation with low frequency was selected as the vibration energy to cause the deformation of tetragonal BaTiO3. It was found that the piezoelectric potential from the deformation could not only successfully degrade 4-chlorophenol but also effectively dechlorinate it at the same time, and five kinds of dechlorinated intermediates, hydroquinone, benzoquinone, phenol, cyclohexanone, and cyclohexanol, were determined...
May 11, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28431360/contrasting-dual-c-cl-isotope-fractionation-offers-potential-to-distinguish-reductive-chloroethene-transformation-from-breakdown-by-permanganate
#16
Eylem Doğan-Subaşı, Martin Elsner, Shiran Qiu, Stefan Cretnik, Siavash Atashgahi, Orfan Shouakar-Stash, Nico Boon, Winnie Dejonghe, Leen Bastiaens
cis-1,2-Dichloroethene (cis-DCE) and trichloroethene (TCE) are persistent, toxic and mobile pollutants in groundwater systems. They are both conducive to reductive dehalogenation and to oxidation by permanganate. In this study, the potential of dual element (C, Cl) compound specific isotope analyses (CSIA) for distinguishing between chemical oxidation and anaerobic reductive dechlorination of cis-DCE and TCE was investigated. Well-controlled cis-DCE degradation batch tests gave similar carbon isotope enrichment factors εC (‰), but starkly contrasting dual element isotope slopes Δδ(13)C/Δδ(37)Cl for permanganate oxidation (εC=-26‰±6‰, Δδ(13)C/Δδ(37)Cl≈-125±47) compared to reductive dechlorination (εC=-18‰±4‰, Δδ(13)C/Δδ(37)Cl≈4...
April 18, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28431359/reconstruction-of-microbial-community-structures-as-evidences-for-soil-redox-coupled-reductive-dechlorination-of-pcp-in-a-mangrove-soil
#17
Yan Xu, Yan He, Xianjin Tang, Philip C Brookes, Jianming Xu
The aim was to investigate the influence of pentachlorophenol (PCP) on the soil microbial communities and the coupled mechanism between PCP reductive dechlorination and soil redox under anaerobic condition. Accordingly, a slurry incubation experiment was carried out in which bacterial and archaeal communities were detected by MiSeq amplicon sequencing. The original microbial community balance was gradually disrupted and new microbial structure was reconstructed subsequently through self-regulation and acclimation during PCP transformation, coupling with the changes of soil biogeochemical redox dynamics...
April 18, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28429272/electrocatalytic-dechlorination-of-2-3-5-trichlorophenol-on-palladium-carbon-nanotubes-nafion-film-titanium-mesh-electrode
#18
Zhirong Sun, Xiaoyue Ma, Xiang Hu
Palladium/carbon nanotubes-nafion film-modified titanium mesh electrode (Pd/CNTs-nafion film/Ti electrode) was prepared and used for catalytic dechlorination of 2,3,5-trichlorophenol (2,3,5-TCP). The influences of factors, such as Pd(2+) concentration, plating solution pH, and electrodeposition time and current, on the preparation of the electrode were studied by cyclic voltammetry (CV) to establish the optimal electrode preparation conditions. Additionally, the CV results highlighted that the addition of the CNTs-nafion film could enhance the electrochemical performance of the electrode...
April 21, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28427682/effects-and-mechanism-of-diclofenac-degradation-in-aqueous-solution-by-us-zn-0
#19
Ting Huang, Guangming Zhang, Shan Chong, Yucan Liu, Nan Zhang, Shunyan Fang, Jia Zhu
A system of ultrasound radiation coupled with Zn(0) was applied to degrade diclofenac. The effects of initial pH, dosage of Zn(0) and ultrasound density were investigated. To further explore the mechanism of the microcosmic reaction, the fresh and used Zn(0) powders were characterized by SEM, XRD and XPS. Radical scavengers were used to determine the oxidation performance of strong oxidizing free radicals on diclofenac, including hydroxyl radicals and superoxide radicals. The results showed that the optimum removal of diclofenac reached to over 85% at pH of 2...
July 2017: Ultrasonics Sonochemistry
https://www.readbyqxmd.com/read/28424844/microbial-reductive-dehalogenation-of-trihalomethanes-by-a-dehalobacter-containing-co-culture
#20
Siyan Zhao, Matthew J Rogers, Jianzhong He
Trihalomethanes such as chloroform and bromoform, although well-known as a prominent class of disinfection by-products, are ubiquitously distributed in the environment due to widespread industrial usage in the past decades. Chloroform and bromoform are particularly concerning, of high concentrations detected and with long half-lives up to several hundred days in soils and groundwater. In this study, we report a Dehalobacter- and Desulfovibrio-containing co-culture that exhibits dehalogenation of chloroform (~0...
April 19, 2017: Applied Microbiology and Biotechnology
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