Read by QxMD icon Read


Haoran Dong, Cong Zhang, Junmin Deng, Zhao Jiang, Lihua Zhang, Yujun Cheng, Kunjie Hou, Lin Tang, Guangming Zeng
Sulfide-modified nanoscale zero-valent iron (S/NZVI) has been considered as an efficient material to degrade trichloroethylene (TCE) in groundwater. However, some critical factors influencing the dechlorination of TCE by S/NZVI have not been investigated clearly. In this study, the effects of Fe/S molar ratio, initial pH, dissolved oxygen and particle aging on TCE dechlorination by S/NZVI (using dithionite as sulfidation reagent) were studied. Besides, the feasibility of reactivation of the aged-NZVI by sulfidation treatment was looked into...
February 7, 2018: Water Research
Anna L Murray, Emily Kumpel, Rachel Peletz, Ranjiv S Khush, Daniele S Lantagne
In microbiological water quality testing, sample dechlorination with sodium thiosulfate is recommended to ensure that results accurately reflect the water quality at sample collection. Nevertheless, monitoring institutions in low-resource settings do not always dechlorinate samples, and there is limited research describing how this practice impacts drinking water quality results. The effect of dechlorination on indicator bacteria counts was evaluated by spiking laboratory water with five Escherichia coli (E...
February 2018: Journal of Water and Health
Li Yang Zhou, Shuai Chen, Hui Li, Shu Guo, Yong Di Liu, Jie Yang
S,S-ethylenediamine-N,N-disuccinic acid (EDDS) enhanced reductive dissolution of α-FeOOH by Shewanella putrefaciens CN32 (CN32), resulting in formation of surface-bound Fe(II) species (FeIIEDDS) to improve reductive dechlorination of carbon tetrachloride (CT). The pseudo-first-order rate constants for bio-reduction extents of α-FeOOH by CN32 in the presence of 1.36 mM EDDS was 0.023 ± 0.0003 d-1 which was higher than without EDDS. The enhancement mechanism of bio-reduction was attributed to the strong complexation ability of EDDS to formed FeIIIEDDS, which could be better utilized by CN32...
January 18, 2018: Chemosphere
Gretchen L W Heavner, Cresten B Mansfeldt, Garrett E Debs, Sage T Hellerstedt, Annette R Rowe, Ruth E Richardson
Using mRNA transcript levels for key functional enzymes as proxies for the organohalide respiration (OHR) rate, is a promising approach for monitoring bioremediation populations in situ at chlorinated solvent-contaminated field sites. However, to date, no correlations have been empirically derived for chlorinated solvent respiring, Dehalococcoides mccartyi (DMC) containing, bioaugmentation cultures. In the current study, genome-wide transcriptome and proteome data were first used to confirm the most highly expressed OHR-related enzymes in the bioaugmentation culture, KB-1TM, including several reductive dehalogenases (RDases) and a Ni-Fe hydrogenase, Hup...
February 8, 2018: Microorganisms
Mengbin Gu, Usman Farooq, Shuguang Lu, Xiang Zhang, Zhaofu Qiu, Qian Sui
The reduced graphene oxide (rGO) supported nano zero-valent iron (nZVI) (nZVI-rGO) was synthesized successfully and applied in the several oxic environments to remove trichloroethylene (TCE). The nZVI-rGO had a better catalytic performance than bare nZVI for the TCE removal. Both aggregation of nZVI and agglomeration of rGO were in part prevented by loading the nZVI nanoparticles on the rGO sheet. Among all the oxic environments, the better removal of TCE was followed as the order of PMS > SPS > H2O2...
January 31, 2018: Journal of Hazardous Materials
Hui Wan, Xiaoyun Yi, Xiaoping Liu, Chunhua Feng, Zhi Dang, Chaohai Wei
Applying an electric field to stimulate the microbial reductive dechlorination of polychlorinated biphenyls (PCBs) represents a promising approach for bioremediation of PCB-contaminated sites. This study aimed to demonstrate the biocathodic film-facilitated reduction of PCB 61 in a sediment-based bioelectrochemical reactor (BER) and, more importantly, the characterizations of electrode-microbe interaction from microbial and electrochemical perspectives particularly in a time-dependent manner. The application of a cathodic potential (-0...
February 2, 2018: Environmental Pollution
Linlin Chen, Junjie Shao, Hui Chen, Caiqin Wang, Xinyi Gao, Xiangyang Xu, Liang Zhu
For enhanced dechlorination of 2,4-dichloronitrobenzene (2,4-DClNB), a coupled microbial electrosynthesis-upflow anaerobic sludge reactor (MES-UASB) was established, and the effect of cathode potential on the performance of combined process was investigated in this study. Results showed that a higher dechlorination efficiency of 78.5 ± 6.1% was achieved in the coupled MES-UASB at -660 mV, and the degradation rate of 4-chloroaniline (4-ClAn) reached 4.61 mg·L-1·d-1 within 120 h at -660 mV of cathode potential in batch experiments...
January 26, 2018: Bioresource Technology
Dong Wang, Jianjun Chen, Yue Peng, Wenzhe Si, Xiansheng Li, Bing Li, Junhua Li
Chlorobenzene (CB) inhibits SCR activity of V-based catalysts at low temperature, though the adsorption amount is small. NH3 adsorption increases due to the break in the C-Cl bond during CB oxidation. The dissociated Cl- ions provide extra Brønsted acid sites, leading to the formation of inactive NH4Cl. Ce and Mn improve dechlorination, forming more NH4Cl on the catalyst surface.
February 7, 2018: Chemical Communications: Chem Comm
Nathaniel J Clark, Benjamin J Shaw, Richard D Handy
Silver nanoparticles (Ag NPs) are known for their antibacterial properties and are used in a growing number of nano-enabled products, with inevitable concerns for releases to the environment. Nanoparticles may also be antigenic and toxic to the haematopoietic system, but the immunotoxic effect of Ag NPs on non-target species such as fishes is poorly understood. This study aimed to assess the effect of Ag NP exposure via the water on the haematopoietic system of rainbow trout, Oncorhynchus mykiss, and to determine whether or not the hazard from Ag NPs was different from that of AgNO3...
January 29, 2018: Ecotoxicology and Environmental Safety
Hongyi Wan, Nicolas J Briot, Anthony Saad, Lindell Ormsbee, Dibakar Bhattacharyya
Functionalized PVDF membrane platforms were developed for environmentally benign in-situ nanostructured Fe/Pd synthesis and remediation of chlorinated organic compounds. To prevent leaching and aggregation, nanoparticle catalysts were integrated into membrane domains functionalized with poly (acrylic acid). Nanoparticles of 16-19 nm were observed inside the membrane pores by using focused ion beam (FIB). This technique prevents mechanical deformation of the membrane, compared to the normal SEM preparation methods, thus providing a clean, smooth surface for nanoparticles characterization...
May 15, 2017: Journal of Membrane Science
Charles E Schaefer, David R Lippincott, Harald Klammler, Kirk Hatfield
An in situ field demonstration was performed in fractured rock impacted with trichloroethene (TCE) and cis-1,2-dichloroethene (DCE) to assess the impacts of contaminant rebound after removing dissolved contaminants within hydraulically conductive fractures. Using a bedrock well pair spaced 2.4m apart, TCE and DCE were first flushed with water to create a decrease in dissolved contaminant concentrations. While hydraulically isolating the well pair from upgradient contaminant impacts, contaminant rebound then was observed between the well pair over 151days...
January 25, 2018: Journal of Contaminant Hydrology
Kumiko Oguma, Kaori Kanazawa, Ikuro Kasuga, Satoshi Takizawa
Ultraviolet light emitting diodes (UV-LEDs) are small mercury-free devices that can be installed at the point of use (POU) of water for disinfection. Considering that heterotrophic bacteria are of concern in drinking water systems, we applied a flow-through UV-LED apparatus to dechlorinated tap water, and determined the heterotrophic plate count (HPC) in samples after UV-LED exposure (UV+) compared to samples without UV-LED application (UV-). The UV+ and UV- samples were maintained at 20 °C to track HPC profiles during storage for seven days...
February 2, 2018: Photochemistry and Photobiology
Xiaomi Wang, Ying Teng, Chen Tu, Yongming Luo, Chris Greening, Ning Zhang, Shixiang Dai, Wenjie Ren, L Zhao, Zhengao Li
Legume-rhizobium symbioses have the potential to remediate soils contaminated with chlorinated organic compounds. Here, the model symbiosis between Medicago sativa and Sinorhizobium meliloti was used to explore the relationships between symbiotic nitrogen fixation and transformation of tetrachlorobiphenyl PCB 77 within this association. 45-day-old seedlings in vermiculite were pre-treated with 5 mg L-1 PCB 77 for 5 days. In PCB-supplemented nodules, addition of the nitrogenase enhancer molybdate significantly stimulated dechlorination by 7...
January 24, 2018: Environmental Science & Technology
Hui Xie, Lusheng Zhu, Jun Wang
Bioremediation of contaminated soils by a combinational approach using specific bacterial species together with ryegrass is a promising strategy, resulting in potentially highly efficient degradation of organic contaminants. The present study tested the combination of strain DXZ9 of Stenotrophomonas sp. with ryegrass to remove DDT and DDE contaminants from soil under natural conditions in a pot experiment. The strain DXZ9 was successfully colonized in the natural soil, resulting in removal rates of approximately 77% for DDT, 52% for DDE, and 65% for the two pollutants combined after 210 days...
January 21, 2018: Environmental Science and Pollution Research International
Rong Yu, Richard G Andrachek, Leo G Lehmicke, David L Freedman
Biostimulation was identified as a potential technology to treat a fractured sandstone aquifer contaminated with trichloroethene (TCE) and cis-1,2-dichloroethene (cis-DCE). Most of the mass of TCE and cis-DCE resides within the rock matrix and strategies to restore groundwater to pre-existing conditions are severely limited by back diffusion. A microcosm study using crushed rock and groundwater from the site was performed to assess biostimulation and natural attenuation. Lactate, hydrogen release compound® (HRC), and emulsified vegetable oil (EVO) significantly increased the rate of TCE reduction to cis-DCE...
January 16, 2018: Science of the Total Environment
Changling Ji, Liang Meng, Hualin Wang
In this study, a composite remediation material for the enhanced reductive dechlorination (ERD) of 1,1,1-trichloroethane (1,1,1-TCA) in aqueous solution was prepared. This material was comprised of biochar as the carrier and adsorbent, and carrageenan (CG) as the embedding medium to entrap the organic carbon sources and zero-valent iron (ZVI). We determined the suitable biochar dosage and organic carbon source in the composite alongside the optimal preparation conditions. Furthermore, using an anaerobic microcosm study, we discussed the performance and possible mechanisms of the composite on 1,1,1-TCA removal in aqueous solution...
January 18, 2018: Environmental Science and Pollution Research International
Ihsan Erden, Cindy J Gleason
Herein, we describe two independent and non-pyrolytic syntheses of an important C12H12 hydrocarbon which had been prepared previously by gas phase thermolysis of compound 6. The first method is based on an unusual dipolar cycloaddition of dichloroketene onto bullvalene. After reductive dechlorination, a Shapiro-Heath reaction of the tosylhydrazone gave the title compound. Alternatively, compound 13 is also obtained from its isomer 6 by a Ag+ catalyzed reaction.
January 17, 2018: Tetrahedron Letters
Gabriela T Niño de Guzmán, Cathleen J Hapeman, Patricia D Millner, Laura L McConnell, Dana Jackson, David Kindig, Alba Torrents
Trichloroethylene (TCE) is a highly effective industrial degreasing agent and known carcinogen. It was frequently buried improperly in landfills and has subsequently become one of the most common groundwater and soil contaminants in the USA. A common strategy to remediate TCE-contaminated sites and to prevent movement of the TCE plumes into waterways is to construct biowalls which consist of biomaterials and amendments to enhance biodegradation. This approach was chosen to contain a TCE plume emanating from a closed landfill in Maryland...
January 11, 2018: Environmental Science and Pollution Research International
Karen R Py-Daniel, Javier Calvo, Carlos M Infante C, Osmindo R Pires Junior, Sergio E Moya, Ricardo B Azevedo
Metal phthalocyanines are promising components in photodynamic therapy. Aluminum phthalocyanine chloride (AlClPc) has been used to treat oral cancer in mice, human carious tissue, lung cancer cells and other conditions. To overcome the high hydrophobicity of AlClPc, phthalocyanine is often encapsulated in nanoformulations. Despite increased usage, little is known about the pharmacokinetics and biodistribution of AlClPc. The aim of this study was the development and validation of a UHPLC-MS method for the determination of AlClPc in solution after extraction from nanoformulations and biological matrices such as plasma and tissue...
March 1, 2018: Talanta
Hyeok Choi
Previously, the concept of reactive activated carbon (RAC), where the porous structure of activated carbon (AC) is impregnated with palladized zerovalent iron, has been proposed to be effective to adsorb and dechlorinate polychlorinated biphenyls (PCBs). To explain the low dechlorination of PCBs bound to actual aquatic sediments under remediation with RAC, this study investigated the role of various solid organic and inorganic sediment components in adsorbing and desorbing PCBs. Detailed fate and transport mechanism of 2-chlorinated biphenyl (2-ClBP) spiked to sediment components, including kaolin, montmorillonite (MMT), coal, graphite, AC, and their mixture, was revealed...
December 17, 2017: Journal of Hazardous Materials
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"