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Fulvic acid

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https://www.readbyqxmd.com/read/28521985/synthesis-and-flocculation-performance-of-a-chitosan-acrylamide-fulvic-acid-ternary-copolymer
#1
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
https://www.readbyqxmd.com/read/28505530/photocatalytic-wastewater-purification-with-simultaneous-hydrogen-production-using-mos2-qd-decorated-hierarchical-assembly-of-znin2s4-on-reduced-graphene-oxide-photocatalyst
#2
Shuqu Zhang, Longlu Wang, Chengbin Liu, Jinming Luo, John Crittenden, Xia Liu, Tao Cai, Jili Yuan, Yong Pei, Yutang Liu
It is attractive to photocatalytically purify wastewater and simultaneously convert solar energy into clean hydrogen energy. However, it is still a challenge owing to the relatively low photocatalytic efficiency of photocatalysts. In this study, we synthesized a molybdenum disulfide (MoS2) quantum dot-decorated 3D nanoarchitecture (MoS2QDs) of indium zinc sulfide (ZnIn2S4) and reduced grapheme oxide (MoS2QDs@ZnIn2S4@RGO) photocatalyst using a simple solvothermal method. The RGO promotes the electron transfer, and the highly dispersed MoS2QDs provides numerous catalytic sites...
May 10, 2017: Water Research
https://www.readbyqxmd.com/read/28499227/organic-carbon-pools-and-soil-biological-fertility-are-affected-by-land-use-intensity-in-mediterranean-ecosystems-of-sardinia-italy
#3
Rosa Francaviglia, Gianluca Renzi, Luigi Ledda, Anna Benedetti
Soil quality is mainly studied from the chemical and physical point of view, whereas soil biochemical and microbiological parameters are relatively more scarcely explored to assess the effect of management practices. This study aimed to evaluate soil organic carbon (SOC) and its pools; soil microbial activity parameters; and the Biological Fertility Index (BFI), in six land uses characteristics of the Mediterranean basin in north-eastern Sardinia. These land uses differed in management intensity and consisted of: tilled vineyard (TV), no tilled grassed vineyard (GV), former vineyards (FV), hay crop and pasture (HC and PA), cork oak forest (CO)...
May 9, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28494309/macroscopic-and-spectroscopic-studies-of-the-enhanced-scavenging-of-cr-vi-and-se-vi-from-water-by-titanate-nanotube-anchored-nanoscale-zero-valent-iron
#4
Baowei Hu, Guohe Chen, Chengan Jin, Jun Hu, Chengcai Huang, Jiang Sheng, Guodong Sheng, Jingyuan Ma, Yuying Huang
Herein, a promising titanate nanotubes (TNT) anchored nanoscale zero-valent iron (NZVI) nanocomposite (NZVI/TNT) was synthesized, characterized and used for the enhanced scavenging of Cr(VI) and Se(VI) from water. The structural identification indicated that NZVI was uniformly loaded on TNT, thereby, the oxidation and aggregation of NZVI was significantly minimized. The macroscopic experimental results indicated that NZVI/TNT exhibited higher efficiency as well as rate on Cr(VI) and Se(VI) scavenging resulted from the good synergistic effect between adsorption and reduction...
April 28, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28494222/distribution-and-incorporation-mode-of-the-herbicide-mcpa-in-soil-derived-organo-clay-complexes
#5
Patrick Riefer, Timm Klausmeyer, Burkhard Schmidt, Andreas Schäffer, Jan Schwarzbauer
The incorporation of xenobiotics into soil, especially via covalent bonds or sequestration has a major influence on the environmental behavior including toxicity, mobility, and bioavailability. The incorporation mode of 4-chloro-2-methylphenoxyacetic acid (MCPA) into organo-clay complexes has been investigated under a low (8.5 mg MCPA/kg soil) and high (1000 mg MCPA/kg soil) applied concentration, during an incubation period of up to 120 days. Emphasis was laid on the elucidation of distinct covalent linkages between non-extractable MCPA residues and humic sub-fractions (humic acids, fulvic acids, and humin)...
May 11, 2017: Journal of Environmental Science and Health. Part. B, Pesticides, Food Contaminants, and Agricultural Wastes
https://www.readbyqxmd.com/read/28469240/capacity-of-humic-substances-to-complex-with-iron-at-different-salinities-in-the-yangtze-river-estuary-and-east-china-sea
#6
Rujun Yang, Han Su, Shenglu Qu, Xuchen Wang
The iron binding capacities (IBC) of fulvic acid (FA) and humic acid (HA) were determined in the salinity range from 5 to 40. The results indicated that IBC decreased while salinity increased. In addition, dissolved iron (dFe), FA and HA were also determined along the Yangtze River estuary's increasing salinity gradient from 0.14 to 33. The loss rates of dFe, FA and HA in the Yangtze River estuary were up to 96%, 74%, and 67%, respectively. The decreases in dFe, FA and HA, as well as the change in IBC of humic substances (HS) along the salinity gradient in the Yangtze River estuary were all well described by a first-order exponential attenuation model: y(dFe/FA/HA, S) = a0 × exp(kS) + y0...
May 3, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28458245/when-soils-become-sediments-large-scale-storage-of-soils-in-sandpits-and-lakes-and-the-impact-of-reduction-kinetics-on-heavy-metals-and-arsenic-release-to-groundwater
#7
Jos P M Vink, Andre van Zomeren, Joris J Dijkstra, Rob N J Comans
Simulating the storage of aerobic soils under water, the chemical speciation of heavy metals and arsenic was studied over a long-term reduction period. Time-dynamic and redox-discrete measurements in reactors were used to study geochemical changes. Large kinetic differences in the net-complexation quantities of heavy metals with sulfides was observed, and elevated pore water concentrations remained for a prolonged period (>1 year) specifically for As, B, Ba, Co, Mo, and Ni. Arsenic is associated to the iron phases as a co-precipitate or sorbed fraction to Fe-(hydr)oxides, and it is being released into solution as a consequence of the reduction of iron...
April 27, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28456035/near-uv-photooxidation-of-as-iii-by-iron-species-in-the-presence-of-fulvic-acid
#8
Ivan P Pozdnyakov, Tamara E Romanova, Xiaojiao Cai, Victoria A Salomatova, Victor F Plyusnin, Ping Na, Olga V Shuvaeva
Photooxidation of As(III) in ternary As(III) - Fe(III) - Fulvic acid system at pH 4 was investigated by optical spectroscopy, steady-state photolysis (365 nm) and atomic-emission spectrometry with inductively coupled plasma techniques. It was found that at all values of [FA]/[Fe] ratio the main photoactive species is OH radical formed by photolysis of Fe(III) hydroxocomplexes. Addition of fulvic acid leads to mainly negative effect on As(III) photooxidation due to the following reasons: (i) slow dark reduction of photoactive Fe(III) species with formation of scattering particles and photoinert Fe(II) species; (ii) formation of photoreductive Fe(III)-FA complexes incapable to oxidize As(III), (iii) competition of both FA and Fe(III)-FA complexes for UVA quanta with FeOH(2+) complex and for OH radicals with As(III)...
April 24, 2017: Chemosphere
https://www.readbyqxmd.com/read/28448748/evaluation-of-humic-substances-removal-from-leachates-originating-from-solid-waste-landfills-in-rio-de-janeiro-state-brazil
#9
Letícia S M S Lima, Ronei De Almeida, Bianca R Quintaes, Daniele M Bila, Juacyara C Campos
This study aimed to evaluate the use of coagulation/flocculation and Fenton processes for the removal of the recalcitrant component, in particular humic substances, from two different leachates generated in the Gericinó and Gramacho landfills in Rio de Janeiro State (Brazil). A coagulation/flocculation process, using FeCl3·6H2O as the coagulant, was applied to the two leachate samples. In the case of the leachate from Gericinó landfill, the treatment removed 93% of color, 71% of TOC, 69% of COD, 76% of HS, 73% of humic acids (HA) and 82% of fulvic acids (FA)...
April 27, 2017: Journal of Environmental Science and Health. Part A, Toxic/hazardous Substances & Environmental Engineering
https://www.readbyqxmd.com/read/28445067/photoelectrochemical-degradation-of-organic-compounds-coupled-with-molecular-hydrogen-generation-using-electrochromic-tio2-nanotube-arrays
#10
Min Seok Koo, Kangwoo Cho, Jeyong Yoon, Wonyong Choi
Vertically aligned TiO2 nanotube arrays (TNTs) were prepared by electrochemical anodization, and then cathodically polarized with dark blue coloration for the dual-functional photoelectrochemical water treatment of organic substrates degradation and accompanying H2 generation. The resulting Blue-TNTs (inner diameter: ∼40 nm; length: ∼9 μm) showed negligible shift in X-ray diffraction pattern compared with the intact TNTs, but the X-ray photoelectron spectra indicated a partial reduction of Ti(4+) to Ti(3+) on the surface...
May 9, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28437609/source-and-biological-response-of-biochar-organic-compounds-released-into-water-relationships-with-bio-oil-composition-and-carbonization-degree
#11
Michele Ghidotti, Daniele Fabbri, Ondřej Mašek, Colin Logan Mackay, Marco Montalti, Andreas Hornung
Water-soluble organic compounds (WSOCs) were extracted from corn stalk biochar produced at increasing pyrolysis temperatures (350-650 °C) and from the corresponding vapors, collected as bio-oil. WSOCs were characterized by gas chromatography (semivolatile fraction), negative electron spray ionization high resolution mass spectrometry (hydrophilic fraction) and fluorescence spectroscopy. The pattern of semivolatile WSOCs in bio-oil was dominated by aromatic products from lignocellulose, while in biochar was featured by saturated carboxylic acids from hemi/cellulose and lipids with concentrations decreasing with decreasing H/C ratios...
May 8, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28431351/role-of-membrane-fouling-substances-on-the-rejection-of-n-nitrosamines-by-reverse-osmosis
#12
Takahiro Fujioka, Hitoshi Kodamatani, Hidenobu Aizawa, Stephen Gray, Kenneth P Ishida, Long D Nghiem
The impact of fouling substances on the rejection of four N-nitrosamines by a reverse osmosis (RO) membrane was evaluated by characterizing individual organic fractions in a secondary wastewater effluent and deploying a novel high-performance liquid chromatography-photochemical reaction-chemiluminescence (HPLC-PR-CL) analytical technique. The HPLC-PR-CL analytical technique allowed for a systematic examination of the correlation between the fouling level and the permeation of N-nitrosamines in the secondary wastewater effluent and synthetic wastewaters through an RO membrane...
July 1, 2017: Water Research
https://www.readbyqxmd.com/read/28424566/influence-of-organic-molecules-on-the-aggregation-of-tio2-nanoparticles-in-acidic-conditions
#13
Karin Danielsson, Julián A Gallego-Urrea, Martin Hassellov, Stefan Gustafsson, Caroline M Jonsson
Engineered nanoparticles released into the environment may interact with natural organic matter (NOM). Surface complexation affects the surface potential, which in turn may lead to aggregation of the particles. Aggregation of synthetic TiO2 (anatase) nanoparticles in aqueous suspension was investigated at pH 2.8 as a function of time in the presence of various organic molecules and Suwannee River fulvic acid (SRFA), using dynamic light scattering (DLS) and high-resolution transmission electron microscopy (TEM)...
2017: Journal of Nanoparticle Research: An Interdisciplinary Forum for Nanoscale Science and Technology
https://www.readbyqxmd.com/read/28407573/assessment-of-mobility-and-bioavailability-of-mercury-compounds-in-sewage-sludge-and-composts
#14
Beata Janowska, Kazimierz Szymański, Robert Sidełko, Izabela Siebielska, Bartosz Walendzik
Content of heavy metals, including mercury, determines the method of management and disposal of sewage sludge. Excessive concentration of mercury in composts used as organic fertilizer may lead to accumulation of this element in soil and plant material. Fractionation of mercury in sewage sludge and composts provides a better understanding of the extent of mobility and bioavailability of the different mercury species and helps in more informed decision making on the application of sludge for agricultural purposes...
April 10, 2017: Environmental Research
https://www.readbyqxmd.com/read/28402898/predicting-potential-release-of-dissolved-organic-matter-from-biochars-derived-from-agricultural-residues-using-fluorescence-and-ultraviolet-absorbance
#15
Ming Li, Afeng Zhang, Haiming Wu, Hai Liu, Jialong Lv
A combination of fluorescence excitation-emission (EEM) spectrophotometry with parallel factor analysis (PARAFAC) and UV-vis spectroscopy was used to assess dissolved organic matter (DOM) release by the wheat straw-derived biochar in various environmental conditions. The results showed that the concentration of dissolved organic carbon (DOC) extracted from the biochar ranged from 435 to 5000mgkg(-1), and the high DOM release would occur under the high temperature and alkaline environmental conditions. Four humic acid-like substances (C1, C2, C4 and C5), one fulvic acid-like substance (C3) and one tryptophan-like substance (C6) were identified by PARAFAC model...
March 31, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28391929/photodegradation-of-17%C3%AE-ethynylestradiol-in-dissolved-humic-substances-solution-kinetics-mechanism-and-estrogenicity-variation
#16
Dong Ren, Bin Huang, Dan Xiong, Huan He, Xiangqi Meng, Xuejun Pan
17α-Ethynylestradiol (EE2) in natural waters may cause adverse effects on organisms due to its high estrogenic potency. Laboratory studies were performed to study the effects of a local humic acid (LHA), fulvic acid (LFA) and Aldrich humic acid (AHA) on the photochemical behavior and estrogenic potency of EE2. Here photolytic experiments demonstrated that pure aqueous EE2 could undergo direct and self-sensitized photodegradation at a global rate of 0.0068hr(-1). Photodegradation rate of EE2 in 5.0mg/L dissolved humic substances (DHS) was determined to be 0...
April 2017: Journal of Environmental Sciences (China)
https://www.readbyqxmd.com/read/28368590/comparison-of-direct-and-indirect-photolysis-in-imazosulfuron-photodegradation
#17
Caitlin Rering, Katryn Williams, Matt Hengel, Ronald Tjeerdema
Imazosulfuron, a sulfonylurea herbicide used in rice cultivation, has been shown to undergo photodegradation in water, but neither the photochemical mechanism nor the role of indirect photolysis is known. The purpose of this study was to investigate the underlying processes that operate on imazosulfuron during aqueous photodegradation. Our data indicate that in the presence of oxygen, most photochemical degradation proceeds through a direct singlet-excited state pathway, whereas triplet-excited state imazosulfuron enhanced decay rates under low dissolved oxygen conditions...
April 7, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28365074/ultraviolet-b-radiation-mobilizes-uranium-from-uranium-dissolved-organic-carbon-complexes-in-aquatic-systems-demonstrated-by-asymmetrical-flow-field-flow-fractionation
#18
Sachin Vilas Nehete, Terje Christensen, Brit Salbu, Hans-Christian Teien
Humic substances have a tendency to form complexes with metal ions in aquatic medium, impacting the metal mobility, decreasing bioavailability and toxicity. Ultraviolet-B (UV-B) radiation exposure degrades the humic substance, changes their molecular weight distribution and their metal binding capacity in aquatic medium. In this study, we experimented the effect of UV-B radiation on the uranium complexed with fulvic acids and humic acids in a soft water system at different pH, uranium concentrations and radiant exposure...
May 5, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28361397/integration-of-coagulation-and-adsorption-for-removal-of-n-nitrosodimethylamine-ndma-precursors-from-biologically-treated-municipal-wastewater
#19
Miaomiao Wang, Yingjie Meng, Defang Ma, Yan Wang, Fengli Li, Xing Xu, Chufan Xia, Baoyu Gao
This study investigated the N-nitrosodimethylamine (NDMA) formation potential of various dissolved organic matter (DOM) fractions in biologically treated municipal wastewater by UF fractionation, XAD-8 resin adsorption isolation, and excitation and emission matrix (EEM) fluorescence spectroscopy. Removal of various NDMA precursor fractions was also analyzed to evaluate the efficiency of traditional water treatment processes (coagulation, adsorption, and coagulation-adsorption). Results showed that NDMA were mainly formed by low molecular weight (MW) fractions (<30 kDa) and hydrophilic fractions (HiS) in biologically treated municipal wastewater...
May 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28355587/exopolymeric-substances-from-drinking-water-biofilms-dynamics-of-production-and-relation-with-disinfection-by-products
#20
M F Lemus Pérez, M Rodríguez Susa
Exopolymeric substances (EPS) as an external matrix of biofilm could react with disinfectants in drinking water networks forming disinfection by-products (DBP). Based on an experimental setup using two chlorine conditions-biofilm 1 (2.6 ± 0.8 mgCl/L) and biofilm 2 (0.7 ± 0.2 mg Cl/L)-samples of biofilms were recovered during 9 campaigns and EPS were extracted. Analyses of SUVA, fluorescence and amino acid (AA) content were carried out on the EPS to observe variation over time and correlations with DBP formation potential (DBPfp) after chlorination...
June 1, 2017: Water Research
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