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https://www.readbyqxmd.com/read/28726221/redox-properties-of-humic-substances-under-different-environmental-conditions
#1
Wenyu Tian, Zhen Yang, Xue Zhang, Weifang Ma, Jie Jiang
Humic substances (HS) are one of the most important parts of dissolved organic matter which are ubiquitous in environments playing an important role in many (bio)geochemical processes. In order to define the effects of environmental conditions on the biological transformation of compounds in the presence of HS, microbial reduction rates of ferrihydrite under different HS concentrations, environmental temperature, and pH values were determined. The results showed that increasing the concentration of standard humic substances (Pahokee peat standard humic acids (PPHA) or Pahokee peat standard fulvic acids (PPFA)) purchased from the International Humic Substances Society could compensate for the certain gap of reduction rates between low temperature (10 °C) and high temperature (35 °C)...
July 19, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28710984/aggregation-behavior-of-tio2-nanoparticles-in-municipal-effluent-influence-of-ionic-strengthen-and-organic-compounds
#2
Meijie Ren, Harald Horn, Fritz H Frimmel
The influence of ionic strengthen and dissolved organic matter (DOM) on the aggregation of TiO2 nanoparticles (NPs) in municipal effluent was investigated. The results demonstrated that DOM promoted the mobility of NPs in aquatic system by synergism between static repulsion and steric effect, while electrolytes were opposite by charge-neutralization. The physical-chemical characteristics of DOM played the major role on the mobility of NPs. Bovine serum albumin (BSA) showed the strongest enhancement on the mobility of TiO2 NPs...
July 11, 2017: Water Research
https://www.readbyqxmd.com/read/28710981/photochemical-generation-and-decay-kinetics-of-superoxide-and-hydrogen-peroxide-in-the-presence-of-standard-humic-and-fulvic-acids
#3
Manabu Fujii, Erika Otani
Reactive oxygen species (ROS) such as superoxide (O2(-)) and hydrogen peroxide (H2O2) can be photochemically generated in aerobic waters containing natural organic matters (NOM) such as humic substances (HS). To investigate the effect of NOM molecular composition on the kinetics and mechanism of ROS transformation, photochemical O2(-) generation and subsequent H2O2 production via catalyzed and uncatalyzed (bimolecular dismutation) O2(-) decay were examined in the presence of 14 types of HS (pH 8.0). By using chemiluminescence and colorimetric techniques, the photochemical O2(-) generation rate, quasi-steady-state O2(-) concentration, catalyzed and uncatalyzed O2(-) decay rates, and H2O2 production rate were found to vary significantly by factors of 72, 18, 14, 320, and 7...
July 9, 2017: Water Research
https://www.readbyqxmd.com/read/28681293/ferrous-activated-peroxymonosulfate-oxidation-of-antimicrobial-agent-sulfaquinoxaline-and-structurally-related-compounds-in-aqueous-solution-kinetics-products-and-transformation-pathways
#4
Yuefei Ji, Lu Wang, Mengdi Jiang, Yan Yang, Peizeng Yang, Junhe Lu, Corinne Ferronato, Jean-Marc Chovelon
Sulfaquinoxaline (SQX) is a coccidiostatic drug widely used in poultry and swine production and has been frequently detected in various environmental compartments such as surface water, groundwater, soils, and sediments. In the present study, degradation of SQX by ferrous ion-activated peroxymonosulfate oxidation process (Fe(II)/PMS), a promising in situ chemical oxidation (ISCO) technique, was systematically investigated. Experimental results showed that Fe(II)/PMS process appeared to be more efficient for SQX removal relative to Fe(II)/persulfate process (Fe(II)/PS)...
July 5, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28654809/interactions-between-stepwise-eluted-sub-fractions-of-fulvic-acids-and-protons-revealed-by-fluorescence-titration-combined-with-eem-parafac
#5
Fanhao Song, Fengchang Wu, Fei Guo, Hao Wang, Weiying Feng, Min Zhou, Yanghui Deng, Yingchen Bai, Baoshan Xing, John P Giesy
In aquatic environments, pH can control environmental behaviors of fulvic acid (FA) via regulating hydrolysis of functional groups. Sub-fractions of FA, eluted using pyrophosphate buffers with initial pHs of 3.0 (FA3), 5.0 (FA5), 7.0 (FA7), 9.0 (FA9) and 13.0 (FA13), were used to explore interactions between the various, operationally defined, FA fractions and protons, by use of EEM-PARAFAC analysis. Splitting of peaks (FA3 and FA13), merging of peaks (FA7), disappearance of peaks (FA9 and FA13), and red/blue-shifting of peaks were observed during fluorescence titration...
June 24, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28647245/transport-and-humification-of-dissolved-organic-matter-within-a-semi-arid-floodplain
#6
Wenming Dong, Jiamin Wan, Tetsu K Tokunaga, Benjamin Gilbert, Kenneth H Williams
In order to understand the transport and humification processes of dissolved organic matter (DOM) within sediments of a semi-arid floodplain at Rifle, Colorado, fluorescence excitation-emission matrix (EEM) spectroscopy, humification index (HIX) and specific UV absorbance (SUVA) at 254nm were applied for characterizing depth and seasonal variations of DOM composition. Results revealed that late spring snowmelt leached relatively fresh DOM from plant residue and soil organic matter down into the deeper vadose zone (VZ)...
July 2017: Journal of Environmental Sciences (China)
https://www.readbyqxmd.com/read/28643123/study-of-the-interactions-of-dissolved-organic-matter-with-zinc-ion-and-the-impact-of-competitive-metal-ions-ca-2-and-mg-2-by-in-situ-absorbance
#7
Tianyu Zhang, Tao Wang, Yujuan Lu
The bioavailability and toxicity of zinc to aquatic life depend on dissolved organic matter (DOM), such as Suwannee River Fulvic Acid (SRFA), which plays an important role in the speciation of zinc. This study examined reactions of SRFA with zinc at different concentrations from pH 3.0 to 9.0, and competitive binding of calcium/magnesium and zinc to SRFA at pH 6.0, using in situ absorbance. Interactions of Zn(2+) with SRFA chromophores were evidenced by the emergence of features in Zn-differential spectra. Among all Zn(2+)-SRFA systems, dominant peaks, located at 235, 275 and 385 nm, and the highest intensity at 235 nm indicated the replacement of protons by the bound Zn(2+)...
June 22, 2017: Environmental Geochemistry and Health
https://www.readbyqxmd.com/read/28641183/size-partitioning-and-mixing-behavior-of-trace-metals-and-dissolved-organic-matter-in-a-south-china-estuary
#8
Wenhao Wang, Min Chen, Laodong Guo, Wen-Xiong Wang
The Jiulong River estuary, located in the southeastern China, suffered from metal pollution due to industrial effluent releases. Mixing of effluent and estuarine water may have significantly affected the size distribution of trace metals and their environmental fate. In the present study, colloidal size distribution of organic matter and selected metals were quantified using asymmetric flow field-flow fractionation (AF4) and ICP-MS. We demonstrated a dominance of dissolved metals in the 1-10kDa fraction, and metals such as Cu, Zn, Ni, Co, Pb, Cd and Mn were mostly regulated by terrestrial fulvic acid...
June 19, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28602005/the-contribution-of-component-variation-and-phytoplankton-growth-to-the-distribution-variation-of-chromophoric-dissolved-organic-matter-content-in-a-mid-latitude-subtropical-drinking-water-source-reservoir-for-two-different-seasons
#9
Qiyuan Sun, Juan Jiang, Yuyi Zheng, Feifeng Wang, Chunshan Wu, Rong-Rong Xie
The distribution variation in chromophoric dissolved organic matter (CDOM) content in mid-latitude subtropical drinking water source reservoirs (MDWSRs) has great significance in the security of aquatic environments and human health. CDOM distribution is heavily influenced by biogeochemical processes and anthropogenic activity. However, little is known regarding the impact of component variation and phytoplankton growth on CDOM distribution variation in MDWSR. Therefore, samples were collected from a representative MDWSR (the Shanzai Reservoir) for analysis...
June 11, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28595127/key-blackening-and-stinking-pollutants-in-dongsha-river-of-beijing-spatial-distribution-and-source-identification
#10
Chen Song, Xiaoling Liu, Yonghui Song, Ruixia Liu, Hongjie Gao, Lu Han, Jianfeng Peng
Elimination of black-stinking water contamination has been listed as an urgent task in the Water pollution prevention action plan promulgated by State Council of China. However, the key blackening and stinking pollutants and their sources are still unclear. In this study, water quality of a black-stinking urban river in Beijing, Dongsha River, was evaluated firstly; then the distribution of the blackening and stinking pollutants was investigated, and the key pollutants and their potential sources were identified; and finally, the health risk of those pollutants was assessed...
June 5, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/28595123/effects-of-humic-acids-with-different-polarities-on-the-photocatalytic-activity-of-nano-tio2-at-environment-relevant-concentration
#11
Wei Wu, Guoqiang Shan, Qian Xiang, Yinqing Zhang, Shujun Yi, Lingyan Zhu
Large volume production and application of nano-TiO2 make it inevitably release to natural waters and its environmental behaviors would be affected by natural organic matters. In this study, the mechanisms of humic acid (HA) affecting the photocatalytic performance of nano-TiO2 were elucidated by using three HA fractions from the same source but with different polarities. Bulk HA was fractionated on a silica gel column to get three fractions with polarity increasing in the order of FA, FB and FC. FA was fulvic acid-like while FB and FC were humic acid-like...
May 11, 2017: Water Research
https://www.readbyqxmd.com/read/28582747/application-of-drum-compost-and-vermicompost-to-improve-soil-health-growth-and-yield-parameters-for-tomato-and-cabbage-plants
#12
Linee Goswami, Anil Nath, Sweety Sutradhar, Satya Sundar Bhattacharya, Ajay Kalamdhad, Kowsalya Vellingiri, Ki-Hyun Kim
Utilization of different types of solid wastes through composting is important for environmental sustainability and restoring soil quality. Although drum composting is an efficient technology, the possibility of heavy metal contamination restricts its large-scale use. In this research, a field experiment was conducted to evaluate the impact of water hyacinth drum compost (DC) and traditional vermicompost (VC) on soil quality and crop growth in an agro-ecosystem cultivated intensively with tomato and cabbage as test crops...
June 2, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/28581715/hulis-enhancement-of-hydroxyl-radical-formation-from-fe-ii-kinetics-of-fulvic-acid-fe-ii-complexes-in-the-presence-of-lung-antioxidants
#13
David H Gonzalez, Christopher K Cala, Qiaoyun Peng, Suzanne E Paulson
Oxidative stress mediated by reactive oxygen species (ROS) is a hypothesized mechanism for particulate-matter related health effects. Fe(II) is a key player in ROS formation in surrogate lung fluid (SLF) containing antioxidants. Humic-like substances (HULIS) in particulate matter such as biomass burning aerosol chelate Fe(II), but the effect on ROS formation in the presence of lung antioxidants is not known. We use Suwanee River Fulvic Acid (SRFA) as a surrogate for HULIS and investigate its effect on OH formation from Fe(II)...
June 20, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28577143/spectroscopic-and-molecular-characterization-of-humic-substances-hs-from-soils-and-sediments-in-a-watershed-comparative-study-of-hs-chemical-fractions-and-the-origins
#14
Morgane Derrien, Yun Kyung Lee, Jae-Eun Park, Penghui Li, Meilian Chen, Sang Hee Lee, Soo Hyung Lee, Jun-Bae Lee, Jin Hur
Optical properties and molecular composition of humic substances (HS) can provide valuable information on the sources and the history of the associated biogeochemical processes. In this study, many well-known spectral and molecular characteristics were examined in eight different HS samples, which were extracted from soils and sediments located in a forested watershed, via two advanced tools including fluorescence excitation emission matrix-parallel factor analysis (EEM-PARAFAC) and high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS)...
July 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28574657/time-dependent-uptake-and-toxicity-of-nickel-to-enchytraeus-crypticus-in-the-presence-of-humic-acid-and-fulvic-acid
#15
Erkai He, Hao Qiu, Rongliang Qiu, Charlotte Rentenaar, Quentin Devresse, Cornelis A M Van Gestel
This study aimed at investigating the influence of different fractions of dissolved organic carbon (DOC) on the uptake and toxicity of nickel (Ni) in the soil invertebrate Enchytraeus crypticus after different exposure times. The addition of DOC as humic acid (HA) or fulvic acid (FA) significantly reduced Ni uptake by E. crypticus in the soil-solution test system. Median lethal effect concentrations were calculated based on total dissolved Ni concentrations (LC50[Ni]), free Ni ion activity (LC50{Ni(2+) }), and Ni body concentrations (LC50Body-Ni )...
June 2, 2017: Environmental Toxicology and Chemistry
https://www.readbyqxmd.com/read/28570895/adsorption-of-pb-and-zn-from-binary-metal-solutions-and-in-the-presence-of-dissolved-organic-carbon-by-dtpa-functionalised-silica-coated-magnetic-nanoparticles
#16
D L Hughes, A Afsar, L M Harwood, T Jiang, D M Laventine, L J Shaw, M E Hodson
The ability of diethylenetriaminepentaacetic acid (DTPA)-functionalised, silica-coated magnetic nanoparticles to adsorb Pb and Zn from single and bi-metallic metal solutions and from solutions containing dissolved organic carbon was assessed. In all experiments 10 mL solutions containing 10 mg of nanoparticles were used. For single metal solutions (10 mg L(-1) Pb or Zn) at pH 2 to 8, extraction efficiencies were typically >70%. In bi-metallic experiments, examining the effect of a background of either Zn or Pb (0...
May 26, 2017: Chemosphere
https://www.readbyqxmd.com/read/28549327/achievement-performance-and-characteristics-of-microbial-products-in-a-partial-nitrification-sequencing-batch-reactor-as-a-pretreatment-for-anaerobic-ammonium-oxidation
#17
Heng Dong, Keyi Zhang, Xiao Han, Bin Du, Qin Wei, Dong Wei
This study was carried out to evaluate achievement, performance and characteristics of microbial products in a partial nitrification sequencing batch reactor as a pretreatment for anaerobic ammonium oxidation (anammox). After 100 days long-term operation, the effluent NO2(-)-N/NH4(+)N ratio of the reactor was average at 1.3 and NO3(-)-N concentration was low by controlling low dissolved oxygen (DO) concentration, which was considered as the ideal influent for anammox. Specific oxygen uptake rate (SOUR) implied that (SOUR)NH4 and (SOUR)NO2 of ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) in sludge changed from 21...
May 20, 2017: Chemosphere
https://www.readbyqxmd.com/read/28537710/elucidating-adsorptive-fractions-of-natural-organic-matter-on-carbon-nanotubes
#18
Mohamed Ateia, Onur G Apul, Yuta Shimizu, Astri Muflihah, Chihiro Yoshimura, Tanju Karanfil
Natural organic matter (NOM) is a heterogeneous mixture of organic compounds that is omnipresent in natural waters. To date, the understanding of the adsorption of NOM components by carbon nanotubes (CNTs) is limited because of the limited number of comprehensive studies in the literature examining the adsorption of NOM by CNTs. In this study, 11 standard NOM samples from various sources were characterized, and their adsorption behaviors on four different CNTs were examined side-by-side using total organic carbon, fluorescence, UV-visible spectroscopy, and high-performance size-exclusion chromatography (HPSEC) analysis...
June 5, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28531557/characterization-of-dissolved-organic-carbon-leached-from-a-woodchip-bioreactor
#19
Ibrahim Abusallout, Guanghui Hua
Woodchip bioreactors are increasingly being applied to remove nitrate from agricultural subsurface drainage. However, dissolved organic carbon (DOC) released from woodchips may negatively affect the aquatic ecosystems and drinking water supplies. The objective of this study was to evaluate the leaching characteristics, disinfection byproduct (DBP) formation potentials, and treatability of DOC derived from a laboratory woodchip bioreactor. Initial flush of woodchips resulted in the release of high organic content from woodchips...
May 13, 2017: Chemosphere
https://www.readbyqxmd.com/read/28521985/synthesis-and-flocculation-performance-of-a-chitosan-acrylamide-fulvic-acid-ternary-copolymer
#20
Tao Lou, Xuejun Wang, Guojun Song, Guangpeng Cui
The flocculant made from natural polymers gained prominence in recent years due to its eco-friendliness and low cost. In this study, two natural polymers of chitosan and fulvic acid were successfully grafted with a synthetic monomer of acrylamide as a new type of flocculant. The prepared chitosan-acrylamide-fulvic acid (CAMFA) exhibited an excellent capacity to remove three typical dyes, the color removal ratios were 97.0%, 91.6%, and 38.2%, respectively, at the dosage of 283mg/L for 100mg/L of acid blue 113, reactive black 5 and methyl orange...
August 15, 2017: Carbohydrate Polymers
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