Photolysis of benzotriazole and formation of its polymerised photoproducts in aqueous solutions under UV irradiation

2011 ◽  
Vol 8 (2) ◽  
pp. 174 ◽  
Author(s):  
You-Sheng Liu ◽  
Guang-Guo Ying ◽  
Ali Shareef ◽  
Rai S. Kookana
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Aqueous Solutions ◽  
Uv Light ◽  
Metal Species ◽  
Industrial Processes ◽  
Inhibitory Effects ◽  
Solution Ph ◽  
Photolysis Rates ◽  
Household Products

Environmental contextBenzotriazole is an anti-corrosion agent that is widely applied in various industrial processes and in household products. It has been found persistent in various aquatic environments. Our investigation found that benzotriazole can be rapidly transformed under UV light to form several photoproducts. Photolysis rates decreased with increasing solution pH, whereas salinity had no significant effect. Metal species Cu2+ and Fe3+, and humic acid in aquatic environment could have inhibitory effects on the photolysis of benzotriazole. AbstractBenzotriazole (BT) is an anti-corrosion agent used widely in some industrial processes and household products, and it has been detected in surface water and ground water due to its high mobility and low biodegradability. We have investigated the photolysis of benzotriazole in aqueous solutions under UV radiation at 254 nm and the effect of pH, salinity, metal species and dissolved organic matter on the photo-transformation processes. Benzotriazole was found to undergo rapid transformation to form several photoproducts. The half-lives for the photolysis of benzotriazole ranged from 2.8 to 14.3 h in various aqueous solutions containing metal ions and dissolved organic matter. Photolysis rates decreased with increasing solution pH, whereas salinity had no significant effect. Metal species Cu2+ and Fe3+, and especially humic acid had inhibitory effects on the photolysis of benzotriazole under UV light irradiation at 254 nm. We propose the formation of three major photoproducts via instantaneous polymerisation of small intermediates generated during the photolysis of benzotriazole including 2,6-diethylaniline, phenazine and 1,6-dihydroxyphenazine.

Effects of Natural Organic Matter on TCE Removal in Groundwater by Zero-Valent Iron: Batch Study

2013 ◽  
Vol 807-809 ◽  
pp. 486-489
Author(s):  
Tong Zhou Liu ◽  
Pin Hua Rao
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Natural Organic Matter ◽  
Early Stage ◽  
Organic Contaminant ◽  
Zero Valent Iron ◽  
Contaminant Removal ◽  
Inhibitory Effects ◽  
Batch Study

An investigation on the effects of humic acid (representing NOM) on TCE (a typical organic contaminant) removal by Fe0in batch settings was carried out. Inhibitory effects of humic acid on Fe0towards TCE removal were observed. At early stage of the experiments, humic acid might partition with TCE, and the adsorption or deposition of humic acid onto Fe0surface would further facilitated TCE immobilization. Once the reduction reactive sites on Fe0surfaces were covered by accumulated humic acid and the partition of TCE to humic acid became saturated, TCE removal in Fe0was observed retarded.

Facile solvothermal synthesis of Fe3O4/magnetic grapefruit peel for adsorptive removal of congo red, humic acid and phosphate from aqueous solutions

2020 ◽  
Vol 10 (1) ◽  
pp. 37-44 ◽  
Author(s):  
Stelgen Inkoua ◽  
Herman Loussala Maloko ◽  
Mave Motandi Koko ◽  
Liangguo Yan
Keyword(s):  
Humic Acid ◽  
Aqueous Solutions ◽  
Congo Red ◽  
Solvothermal Reaction ◽  
Magnetic Composite ◽  
Order Kinetic ◽  
Solution Ph ◽  
Grapefruit Peel ◽  
The Fourier Transform ◽  
High Level

An environment-friendly and economical magnetic composite, namely Fe3O4/GP, was produced from grapefruit peel (GP) and ferric chloride via the solvothermal method in one easy step, and was used to remove Congo red (CR), humic acid (HA), and phosphate (P) from aqueous solutions. The Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM) procedures and specific surface area and zeta potential determination were applied to describe the structure of Fe3O4/GP composite. The results shown the Fe3O4 particles, which fabricated during the solvothermal reaction, were distributed evenly on the surface of GP. Then Fe3O4/GP composite also presented a high level of magnetism, and thus could be separated quickly from suspension by an external magnet. The adsorption efficiencies of Fe3O4/GP for CR, HA, and P were 92.88%, 47.45%, and 99.02%, which were found uninfluenced by the initial solution pH and attained the equilibrium state within 10 min. The kinetic and isothermal tests were performed and the data were consistent with the pseudo-second-order kinetic equation and the Freundlich model.

Water Solubility Enhancement of DDT by Humic Acid and Extracellular Organic Matter of Aquatic Algae

2012 ◽  
Vol 518-523 ◽  
pp. 565-568 ◽  
Author(s):  
Hua Ma ◽  
Fu Yi Cui ◽  
Zhi Wei Zhao ◽  
Zhi Quan Liu ◽  
Dong Mei Liu
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Water Body ◽  
Sampling Method ◽  
Water Solubility ◽  
Solubility Enhancement ◽  
Absorption Coefficients ◽  
Solution Ph ◽  
Eutrophic Water ◽  
Extracellular Organic Matter

The water solubility enhancement of 2,4´-DDT and 4,4´-DDT by humic acid and extracellular organic matter released from Microcystis aeruginosa was investigated by a ingenious sampling method and increasing apparent solute solubilities. Water solubility enhancements of the two DDT isomerizes by both humic acid and extracellular organic matter at the solution pH 7-11, and their solubilities increased with the increase of pH. Absorption coefficients Ciw (2,4´-DDT and 4,4´-DDT) increased with the increase of pH for HA and EOM, but Ciw for EOM are about two times than for HA at same TOC concentrations. The results suggested that more attentions should be paid to the enhancement of organic chemicals by EOM, especially in eutrophic water body where an increasing algae population usually appears, and the enhancement of DDT solubility by EOM may increase the risk of pesticide residues to organisms.

scholarly journals Adsorption of Triclocarban on Pristine and Irradiated MWCNTs in Aqueous Solutions

2019 ◽  
Vol 70 (8) ◽  
pp. 2835-2842 ◽  
Author(s):  
Ion Ion ◽  
Raluca Madalina Senin ◽  
Georgeta Ramona Ivan ◽  
Sanda Maria Doncea ◽  
Michael Patrick Henning ◽  
...  
Keyword(s):  
Experimental Data ◽  
Organic Matter ◽  
Humic Acid ◽  
Aqueous Solutions ◽  
Natural Organic Matter ◽  
Environmental Conditions ◽  
Sorption Process ◽  
Ph Values ◽  
Different Temperatures ◽  
The Impact

The adsorption of triclocarban was investigated on pristine and irradiated MWCNTs, at different temperatures, in aqueous synthetic samples at different pH values and for different concentrations of humic acid (HA) from natural organic matter. Commonly used models of the adsorption isotherms, Freundlich and Langmuir were selected to fit the experimental data. The effects of TCC concentration, of the temperature and of the concentration of humic acid from natural organic matter were tested to study the impact of the environmental conditions over the sorption process.

scholarly journals Impact of natural organic matter on bromate removal in the sulfite/UV-L advanced reduction process

2016 ◽  
Vol 17 (2) ◽  
pp. 461-471 ◽  
Author(s):  
Bahngmi Jung ◽  
Aya Safan ◽  
Venkata Sai Vamsi Botlaguduru ◽  
Bill Batchelor ◽  
Ahmed Abdel-Wahab
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Uv Light ◽  
Degradation Kinetics ◽  
Reduction Process ◽  
Photochemical Reactions ◽  
Natural Environments ◽  
Solution Ph ◽  
Advanced Reduction ◽  
The Impact

Advanced reduction processes (ARPs) are treatment processes that involve combining reducing reagents and activating tools to produce highly reactive reducing free radicals. The process has proven effective for treating oxidized contaminants, and the effects of process variables on the degradation kinetics of various target contaminants have been investigated in our previous studies. In natural environments, natural organic matter (NOM) is found in surface or ground water. NOM absorbs UV light and can react with photochemically produced radicals, thus affecting target contaminant photochemical reactions and further influencing the efficiency of ARP. This study examines the impact of humic acid (HA) and Suwanee River NOM on bromate reduction rates with UV irradiation using a low-pressure mercury UV lamp. The effects of the sulfite dose, solution pH, and light intensity are studied and the pseudo-first-order rate constants in the presence of HA (kobs,HA) are compared to those observed in the absence of HA (kobs). At low HA concentrations of 1 mg L−1, kobs,HA was larger than kobs; however, kobs,HA was less than kobs at higher HA concentrations. Furthermore, kobs,HA did not increase with increasing sulfite doses in the presence of HA, which is unlike the behavior of kobs.

Characterization of dissolved organic matter (DOM) extracted from soils by hot water percolation (HWP)

2010 ◽  
Vol 59 (1) ◽  
pp. 99-108 ◽  
Author(s):  
M. Takács ◽  
Gy. Füleky
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Natural Organic Matter ◽  
Extraction Methods ◽  
Soil Samples ◽  
Hot Water ◽  
Soil Extracts ◽  
Water Percolation ◽  
Soil Humic Acid

The Hot Water Percolation (HWP) technique for preparing soil extracts has several advantages: it is easily carried out, fast, and several parameters can be measured from the same solution. The object of this study was to examine the possible use of HWP extracts for the characterization of soil organic matter. The HPLC-SEC chromatograms, UV-VIS and fluorescence properties of the HWP extracts were studied and the results were compared with those of the International Humic Substances Society (IHSS) Soil Humic Acid (HA), IHSS Soil Fulvic Acid (FA) and IHSS Suwannee Natural Organic Matter (NOM) standards as well as their HA counterparts isolated by traditional extraction methods from the original soil samples. The DOM of the HWP solution is probably a mixture of organic materials, which have some characteristics similar to the Soil FA fractions and NOM. The HWP extracted organic material can be studied and characterized using simple techniques, like UV-VIS and fluorescence spectroscopy.

Characteristics of fouling due to clay-organic substances in potable water treatment by ultrafiltration

1996 ◽  
Vol 34 (9) ◽  
pp. 157-164 ◽  
Author(s):  
Kim C.-H. ◽  
M. Hosomi ◽  
A. Murakami ◽  
M. Okada
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Humic Acid ◽  
Fulvic Acid ◽  
Size Distribution ◽  
Ultrafiltration Membrane ◽  
Organic Substances ◽  
Decomposition Products ◽  
Microbial Decomposition ◽  
Fouling Materials

Effects of clay on fouling due to organic substances and clay were evaluated by model fouling materials and kaolin. Model fouling materials selected were protein, polysaccharide, fulvic acid, humic acid and algogenic matter (EOM:ectracellular organic matter, microbial decomposition products) and kaolin was selected as the clay material. Polysulfone membrane (MWCO(Molecular Weight Cut-Off) 10,000, 50,000 and 200,000) was used as an ultrafiltration membrane. In particular, the flux measurement of solutions containing algogenic matter used an ultrafiltration membrane of MWCO 50,000. The flux of protein and polysaccharide with coexistence of kaolin increased in the case of the ratio of MW/MWCO being greater than one, but did not increase in the case of the MW/MWCO ratio being below one. In contrast, the flux of fulvic acid and humic acid with coextence of kaolin decreased regardless of the ratio of MW/MWCO. The addition of dispersion agent and coagulant in the organic substances and kaolin mixture solution changed the size distribution of kaolin, and resulted in a change of the flux. EOM and microbial decomposition products decreased with the increase of the fraction of organic matter having molecular weight more than MWCO of membrane. The flux of the algogenic organic matter with coexistence of kaolin decreased with the increase of the amount of kaolin. It was suggested that the decline of the flux with coexistence of kaolin was due to the change of the resistance of the kaolin cake layer corresponding to the change in kaolin size distribution with charge.

scholarly journals Effect of Plant Growth Regulators on Protease Activity in Forest Floor of Norway Spruce Stand

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 665
Author(s):  
Ladislav Holik ◽  
Jiří Volánek ◽  
Valerie Vranová
Keyword(s):  
Organic Matter ◽  
Proteolytic Activity ◽  
Protease Activity ◽  
Forest Floor ◽  
Soil Microbial Activity ◽  
Inhibitory Effects ◽  
Chlorocholine Chloride ◽  
Soil Microbial ◽  
Native Soil ◽  
Transformation Processes

Soil proteases are involved in organic matter transformation processes and, thus, influence ecosystem nutrient turnovers. Phytohormones, similarly to proteases, are synthesized and secreted into soil by fungi and microorganisms, and regulate plant rhizosphere activity. The aim of this study was to determine the effect of auxins, cytokinins, ethephon, and chlorocholine chloride on spruce forest floor protease activity. It was concluded that the presence of auxins stimulated native proteolytic activity, specifically synthetic auxin 2-naphthoxyacetic acid (16% increase at added quantity of 5 μg) and naturally occurring indole-3-acetic acid (18%, 5 μg). On the contrary, cytokinins, ethephon and chlorocholine chloride inhibited native soil protease activity, where ethephon (36% decrease at 50 μg) and chlorocholine chloride (34%, 100 μg) showed the highest inhibitory effects. It was concluded that negative phytohormonal effects on native proteolytic activity may slow down organic matter decomposition rates and hence complicate plant nutrition. The study enhances the understanding of rhizosphere exudate effects on soil microbial activity and soil nitrogen cycle.

scholarly journals Rapid Degradation of Carbon Tetrachloride by Microscale Ag/Fe Bimetallic Particles

2021 ◽  
Vol 18 (4) ◽  
pp. 2124
Author(s):  
Xueqiang Zhu ◽  
Lai Zhou ◽  
Yuncong Li ◽  
Baoping Han ◽  
Qiyan Feng
Keyword(s):  
Humic Acid ◽  
Catalytic Reduction ◽  
Direct Reduction ◽  
Cost Effective ◽  
Degradation Efficiency ◽  
Pseudo First Order Reaction ◽  
Solution Ph ◽  
Reaction Stage ◽  
Bimetallic Particles ◽  
Slow Reaction

Cost-effective zero valent iron (ZVI)-based bimetallic particles are a novel and promising technology for contaminant removal. The objective of this study was to evaluate the effectiveness of CCl4 removal from aqueous solution using microscale Ag/Fe bimetallic particles which were prepared by depositing Ag on millimeter-scale sponge ZVI particles. Kinetics of CCl4 degradation, the effect of Ag loading, the Ag/Fe dosage, initial solution pH, and humic acid on degradation efficiency were investigated. Ag deposited on ZVI promoted the CCl4 degradation efficiency and rate. The CCl4 degradation resulted from the indirect catalytic reduction of absorbed atomic hydrogen and the direct reduction on the ZVI surface. The CCl4 degradation by Ag/Fe particles was divided into slow reaction stage and accelerated reaction stage, and both stages were in accordance with the pseudo-first-order reaction kinetics. The degradation rate of CCl4 in the accelerated reaction stage was 2.29–5.57-fold faster than that in the slow reaction stage. The maximum degradation efficiency was obtained for 0.2 wt.% Ag loading. The degradation efficiency increased with increasing Ag/Fe dosage. The optimal pH for CCl4 degradation by Ag/Fe was about 6. The presence of humic acid had an adverse effect on CCl4 removal.

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