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Arsenic and chromate removal from water by iron chips-Effects of anions

ZHANG Ruihua, SUN Hongwen, YIN Jin

《环境科学与工程前沿（英文）》 2008年 第2卷 第2期   页码 203-208 doi: 10.1007/s11783-008-0036-6

摘要： The purpose of this study is to estimate the removal efficiency of As and Cr (VI) by one kind of industrial waste – iron chips, as well as to estimate the effects of typical inorganic anions (sulfate, phosphate, and nitrate

关键词： phosphate     removal efficiency     industrial     typical inorganic    

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Long-term adaptive evolution of

Yong Xiao, Changye Xiao, Feng Zhao

《环境科学与工程前沿（英文）》 2020年 第14卷 第1期 doi: 10.1007/s11783-019-1182-8

摘要： Shewanella oneidensis MR-1 was acclimated to grow with Cr(VI) of 190 mg/L. Whole genomes from 7 populations at different acclimation stages were sequenced. Gene mutations mainly related to efflux pumps and transporters. An adaptation mechanism of MR-1 to high concentration of Cr(VI) was proposed. Acclimation is the main method to enhance the productivity of microorganisms in environmental biotechnology, but it remains uncertain how microorganisms acquire resistance to high concentrations of pollutants during long-term acclimation. Shewanella oneidensis MR-1 was acclimated for 120 days with increasing hexavalent chromium (Cr(VI)) concentrations from 10 to 190 mg/L. The bacterium was able to survive from the highly toxic Cr(VI) environment due to its enhanced capability to reduce Cr(VI) and the increased cell membrane surface. We sequenced 19 complete genomes from 7 populations of MR-1, including the ancestral strain, the evolved strains in Cr(VI) environment on days 40, 80 and 120 and their corresponding controls. A total of 27, 49 and 90 single nucleotide polymorphisms were found in the Cr(VI)-evolved populations on days 40, 80 and 120, respectively. Nonsynonymous substitutions were clustered according to gene functions, and the gene mutations related to integral components of the membrane, including efflux pumps and transporters, were the key determinants of chromate resistance. In addition, MR-1 strengthened the detoxification of Cr(VI) through gene variations involved in adenosine triphosphate binding, electron carrier activity, signal transduction and DNA repair. Our results provide an in-depth analysis of how Cr(VI) resistance of S. oneidensis MR-1 is improved by acclimation, as well as a genetic understanding of the impact of long-term exposure of microorganisms to pollution.

关键词： Environmental biotechnology     Acclimation     Chromate resistance     Efflux pumps     Detoxification    

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Crosslinking acrylamide with EDTA-intercalated layered double hydroxide for enhanced recovery of Cr(VI) and Congo red: Adsorptive and mechanistic study

Jing Li, Haiqin Yu, Xue Zhang, Rixin Zhu, Liangguo Yan

《环境科学与工程前沿（英文）》 2020年 第14卷 第3期 doi: 10.1007/s11783-020-1229-x

摘要： Functional groups of AM and EDTA in composite increased removal of Cr(VI) and CR. Removal process reached equilibrium within 30 min and was minimally affected by pH. Elimination of Cr(VI) was promoted by coexisting CR. Adsorption process of CR was less influenced by the presence of Cr(VI). Mechanisms were electrostatic attraction, surface complexation and anion exchange. We prepared ethylenediaminetetraacetic acid (EDTA)-intercalated MgAl-layered double hydroxide (LDH-EDTA), then grafted acrylamide (AM) to the LDH-EDTA by a cross-linking method to yield a LDH-EDTA-AM composite; we then evaluated its adsorptive ability for Congo red (CR) and hexavalent chromium (Cr(VI)) in single and binary adsorption systems. The adsorption process on LDH-EDTA-AM for CR and Cr(VI) achieved equilibrium quickly, and the removal efficiencies were minimally affected by initial pH. The maximum uptake quantities of CR and Cr(VI) on LDH-EDTA-AM were 632.9 and 48.47 mg/g, respectively. In mixed systems, chromate removal was stimulated by the presence of CR, while the adsorption efficiency of CR was almost not influenced by coexisting Cr(VI). The mechanisms involved electrostatic attraction, surface complexation, and anion exchange for the adsorption of both hazardous pollutants. In the Cr(VI) adsorption process, reduction also took place. The removal efficiencies in real contaminated water were all higher than those in the laboratory solutions.

关键词： Chromate     Dye adsorption     Simultaneous removal     Cross-linking method     Amino functionalization    

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标题 作者 时间 类型 操作

Arsenic and chromate removal from water by iron chips-Effects of anions

ZHANG Ruihua, SUN Hongwen, YIN Jin

期刊论文

Long-term adaptive evolution of

Yong Xiao, Changye Xiao, Feng Zhao

期刊论文

Crosslinking acrylamide with EDTA-intercalated layered double hydroxide for enhanced recovery of Cr(VI) and Congo red: Adsorptive and mechanistic study

Jing Li, Haiqin Yu, Xue Zhang, Rixin Zhu, Liangguo Yan

期刊论文