Photooxidation of 2,4-dichlorophenoxyacetic acid by ferrous oxalate-mediated system

2004 ◽  
Vol 49 (4) ◽  
pp. 117-122 ◽  
Author(s):  
C.Y. Kwan ◽  
W. Chu
Keyword(s):  
Hydrogen Peroxide ◽  
Uv Light ◽  
Reaction Rates ◽  
Dichlorophenoxyacetic Acid ◽  
Ferrous Ions ◽  
Solution Ph ◽  
Ferrous Oxalate ◽  
Radical Production ◽  
Initial Ph ◽  
2,4 Dichlorophenoxyacetic Acid

The photodegradation of a herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) by ferrous oxalate/UV/H2O2 was studied. Ferrous oxalate, the more photoactive and reactive species, was found to react faster with hydrogen peroxide for hydroxyl radical production than ferrous ions under UV irradiation. About 2.9 times greater rate enhancement was found with the addition of 0.3 mM oxalate than that of a solution containing 0.1 mM Fe2+ and 1 mM H2O2 in the presence of UV light at 253.7 nm. The kinetics dependence of hydrogen peroxide concentration and initial solution pH were also investigated. A threefold increase in peroxide concentration could accelerate the removal of 2,4-D and nearly complete the reaction in 30 min of illumination. The initial decay rate of 2,4-D treated by ferrous oxalate/UV/H2O2 accelerated from 0.0029 to 0.0034 s-1 and the overall removal of the starting material increased from 78% to 99.9%. The 2,4-D transformation at lower initial pH had higher reaction rates than that at higher pH and different reaction mechanisms were identified. The efficiency of the herbicide decomposition was retarded 2.6 times and 9.6 times as initial pH increased from 2.8 to 5.1 and 9.0, respectively.

Photocatalytic Treatment of Wastewater From 5–Fluorouracil Manufacturing

1996 ◽  
Vol 118 (1) ◽  
pp. 2-8 ◽  
Author(s):  
M. Anheden ◽  
D. Y. Goswami ◽  
G. Svedberg
Keyword(s):  
Hydrogen Peroxide ◽  
Photocatalytic Oxidation ◽  
Uv Light ◽  
Substantial Reduction ◽  
Reduction Rate ◽  
Reaction Rates ◽  
Batch Experiments ◽  
Cod Reduction ◽  
Potential Use ◽  
Percent Decrease

This paper presents some of the experimental results from a study conducted to demonstrate the potential use of photocatalytic oxidation for decolorization and COD reduction of wastewater from 5–fluorouracil manufacturing. A series of batch experiments, were carried out using diluted solutions of the wastewater with 0.1 percent w/v TiO2. Low pressure mercury lamps were used to simulate the UV part of sunlight. The experiments showed that a complete decolorization and a substantial reduction of COD was achieved within 20 hours with a 20 percent solution. During the reaction period, the pH was noted to decrease considerably, indicating formation of acids. Adding hydrogen peroxide to the solution was found to significantly increase the reaction rates. Adding 2400 ppm of H2O2 gave an 80 percent decrease in color in one hour and a 70-80 percent decrease in COD in 20 hours. The influence of UV-light intensity was also examined. This experiment showed that with a UV-intensity of 15 W/m2, i.e., a cloudy day, the decolorization rate was still considerable, while the COD reduction rate was very low.

scholarly journals Heterogeneous Fenton-Like Catalytic Degradation of 2,4-Dichlorophenoxyacetic Acid by Nano-Scale Zero-Valent Iron Assembled on Magnetite Nanoparticles

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2909 ◽  
Author(s):  
Xiaofan Lv ◽  
Yiyang Ma ◽  
Yangyang Li ◽  
Qi Yang
Keyword(s):  
Hydrogen Peroxide ◽  
Synergistic Effects ◽  
Degradation Process ◽  
Zero Valent Iron ◽  
Dichlorophenoxyacetic Acid ◽  
Heterogeneous Fenton ◽  
Reaction Conditions ◽  
Nano Zero Valent Iron ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Better Than

Fe0@Fe3O4 nanoparticles with dispersibility and stability better than single nano zero-valent iron (nZVI) were synthesized and combined with hydrogen peroxide to constitute a heterogeneous Fenton-like system, which was creatively applied in the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D). The effects of different reaction conditions like pH, hydrogen peroxide concentration, temperature, and catalyst dosage on the removal of 2,4-D were evaluated. The target pollutant was completely removed in 90min; nearly 66% of them could be mineralized, and the main intermediate product was 2,4-dichlorophenol. Synergistic effects between nZVI and Fe3O4 made the 2,4-D degradation efficiency in the Fe0@Fe3O4/H2O2 system greater than in either of them alone. More than a supporter, Fe3O4 could facilitate the degradation process by releasing ferrous and ferric ions from the inner structure. The reduction of 2,4-D was mainly attributed to hydroxyl radicals including surface-bound ∙OH and free ∙OH in solution and was dominated by the former. The possible mechanism of this Fe0@Fe3O4 activated Fenton-like system was proposed.

scholarly journals Removal of Polyvinyl Alcohol Using Photoelectrochemical Oxidation Processes Based on Hydrogen Peroxide Electrogeneration

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Kai-Yu Huang ◽  
Chih-Ta Wang ◽  
Wei-Lung Chou ◽  
Chi-Min Shu
Keyword(s):  
Hydrogen Peroxide ◽  
Light Intensity ◽  
Removal Efficiency ◽  
Flow Rate ◽  
Current Density ◽  
Uv Light ◽  
Supporting Electrolyte ◽  
Oxygen Flow Rate ◽  
Oxygen Flow ◽  
Solution Ph

This study investigates the removal efficiency of PVA from aqueous solutions using UV irradiation in combination with the production of electrogenerated hydrogen peroxide (H2O2) at a polyacrylonitrile-based activated carbon fiber (ACF) cathode. Three cathode materials (i.e., platinum, graphite, and ACF) were fed with oxygen and used for the electrogeneration of H2O2. The amount of electrogenerated H2O2produced using the ACF cathode was five times greater than that generated using the graphite cathode and nearly 24 times greater than that from platinum cathode. Several parameters were evaluated to characterize the H2O2electrogeneration, such as current density, oxygen flow rate, solution pH, and the supporting electrolyte used. The optimum current density, oxygen flow rate, solution pH, and supporting electrolyte composition were found to be 10 mA cm−2, 500 cm3 min−1, pH 3, and Na2SO4, respectively. The PVA removal efficiencies were achieved under these conditions 3%, 16%, and 86% using UV, H2O2electrogeneration, and UV/H2O2electrogeneration, respectively. A UV light intensity of 0.6 mW cm−2was found to produce optimal PVA removal efficiency in the present study. A simple kinetic model was proposed which confirmed pseudo-first-order reaction. Reaction rate constant (kap) was found to depend on the UV light intensity.

Optimization of Operating Parameters for Decolorization of Metal Complex Dyes by UV/H2O2 Process

2011 ◽  
Vol 347-353 ◽  
pp. 2245-2248
Author(s):  
Jing Jian Zhu ◽  
Long Lu ◽  
Jian Xin Chen
Keyword(s):  
Activation Energy ◽  
Hydrogen Peroxide ◽  
Metal Complex ◽  
Uv Light ◽  
Operating Parameters ◽  
Light Wavelength ◽  
Initial Ph ◽  
Suitable Amount ◽  
Reaction Activation Energy ◽  
Metal Complex Dyes

In this paper, the effects of operating parameters such as UV light wavelength, initial pH, reaction temperature and hydrogen peroxide concentration on decolorization of metal complex dyes (Neutral Bordeaux GRL, Neutral Pink BL and Neutral Blue BNL) by UV/H2O2process were studied in detail. The results showed that the decolorization rate constants were obviously enhanced with the increase of UV intensity. In UV (254nm)/H2O2system, 94.4% decolorization of Neutral Bordeaux GRL, 99.2% decolorization of Neutral Pink BL and 65.4% decolorization of Neutral Blue BNL were achieved after 60 min reaction. The results also indicated that both suitable amount of H2O2and initial pH were needed for effective decolorization of different metal complex dyes. The reaction activation energy of Neutral Bordeaux GRL, Neutral Pink BL and Neutral Blue BNL were 3.43, 14.4 and 23.39 KJ mol-1, respectively.

scholarly journals Synthesis and characterization of gold nanoparticles on titanium dioxide for the catalytic photodegradation of 2,4-dichlorophenoxyacetic acid

2018 ◽  
Vol 16 (5) ◽  
Author(s):  
E. Romero Torres ◽  
M. Gutiérrez Arzaluz ◽  
V Mugica Alvarez ◽  
L. González Reyes ◽  
M. Torres Rodríguez ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Titanium Dioxide ◽  
Uv Light ◽  
Anatase Phase ◽  
Precipitation Method ◽  
Dichlorophenoxyacetic Acid ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Average Size ◽  
2,4 Dichlorophenoxyacetic Acid

The photocatalytic degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) using a Au/TiO2 catalyst and ultraviolet (UV) light energy source (9 mW/cm2) discussed. Gold nanoparticles were synthesized by controlled urea reduction and deposited on titanium dioxide (TiO2) by the deposition-precipitation method. The average size of the nanoparticles was 6-8 nm. X-ray diffraction (XRD) characterization confirmed that TiO2 was present in the anatase phase, whereas the presence and particle size of gold were determined by transmission electron microscopy (TEM). The results of the degradation showed that the activity of TiO2 was improved when Au nanoparticles were present on the surface. The reactions were performed at atmospheric pressure and room temperature.

scholarly journals Cobalt Oxide-Modified Titanium Dioxide Nanoparticle Photocatalyst for Degradation of 2,4-Dichlorophenoxyacetic Acid

2017 ◽  
Vol 17 (2) ◽  
pp. 284 ◽  
Author(s):  
Leny Yuliati ◽  
Nur Azmina Roslan ◽  
Wai Ruu Siah ◽  
Hendrik Oktendy Lintang
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Photocatalytic Degradation ◽  
Cobalt Oxide ◽  
Uv Light ◽  
Dichlorophenoxyacetic Acid ◽  
Photocatalytic Reaction ◽  
Impregnation Method ◽  
Titanium Dioxide Nanoparticle ◽  
2,4 Dichlorophenoxyacetic Acid

2,4-dichlorophenoxyacetic acid (2,4-D) has been recognized as a possibly carcinogenic compound to human, therefore, 2,4-D should be treated before it is discharged to the environment. Photocatalytic degradation of 2,4-D has been proposed as one of the best methods that offer environmentally safe process. In the present research, titanium dioxide (TiO2) was modified with cobalt oxide (CoO) and tested for photocatalytic degradation of 2,4-D under UV light irradiation. Different amounts of CoO (0.1, 0.5, 1 and 5 mol%) were added onto TiO2 by an impregnation method. The photocatalytic reaction was monitored and analyzed by measurement of 2,4-D absorbance using UV spectrophotometer. After 1 h photocatalytic reaction, it was confirmed that the sample with low loading of 0.1 mol% gave the highest photocatalytic activity among the bare and modified TiO2 photocatalysts. The photocatalytic activity was decreased with the increase of CoO loading, suggesting that the optimum amount of CoO was an important factor to improve the performance of TiO2. Based on fluorescence spectroscopy, such addition of CoO resulted in the reduced emission intensity, which showed the successful decrease in the electron-hole recombination.

scholarly journals Ultrasound–acid modified Merremia vitifolia biomass for the biosorption of herbicide 2,4-D from aqueous solution

2020 ◽  
Author(s):  
Meethale Theruvinthalakkal Aswani ◽  
Manoj Yadav ◽  
Amgoth Vinod Kumar ◽  
Shashank Tiwari ◽  
Tarun Kumar ◽  
...  
Keyword(s):  
Electrostatic Interactions ◽  
Entropy Change ◽  
Dichlorophenoxyacetic Acid ◽  
Order Kinetic ◽  
Biosorption Capacity ◽  
Diffusion Limitations ◽  
Initial Ph ◽  
Equilibrium Data ◽  
Batch Biosorption ◽  
2,4 Dichlorophenoxyacetic Acid

Abstract In this work, a biosorbent was prepared by the ultrasound–acid treatment of Merremia vitifolia plant and tested for the removal of 2,4-dichlorophenoxyacetic acid (2,4-D), a phenoxy herbicide. Optimal values of five batch biosorption parameters namely stirring speed, contact time, biosorbent dosage, initial pH and initial adsorbate concentration were experimentally obtained in sequential manner for an enhanced biosorption capacity. The kinetics of the biosorption of 2,4-D were best described by the pseudo first order kinetic model (R2 = 0.99) and the biosorption equilibrium data was successfully fitted to the Langmuir adsorption isotherm (R2 = 0.99) with a maximum biosorption capacity of 66.93 mg g−1. The mechanism of biosorption was investigated using two intraparticle diffusion models (Weber and Boyd), Dubinin–Radushkevich isotherm model and electrostatic interactions. The presence of intraparticle and film diffusion limitations for the biosorption was confirmed along with the physical and chemical nature of the biosorption. The thermodynamic parameters of the biosorption were calculated using the equilibrium data obtained at four different temperatures. The entropy change for biosorption was found to be negative indicating the decreased randomness at the interface. Desorption studies were carried out using different solvents and the percentages of desorption were compared.

Degradation of Ciprofloxacin in Aqueous Solution by the Fenton Process

2012 ◽  
Vol 610-613 ◽  
pp. 352-355 ◽  
Author(s):  
Ji Feng Yang ◽  
Hong Hui Chen
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Oxidation Process ◽  
Ph Value ◽  
Fenton Process ◽  
Ferrous Ions ◽  
Reaction Conditions ◽  
Initial Ph ◽  
Optimum Reaction ◽  
Ciprofloxacin Removal

The present study provides results describing the degradation performance of ciprofloxacin antibiotic via Fenton treatment. The effect of reaction conditions including the initial pH value, and dosages of ferrous ions and hydrogen peroxide on ciprofloxacin and COD removal was investigated. Ciprofloxacin removal efficiency of more than 90% was achieved under optimum reaction conditions of pH value of 2, dosages of 0.75 mmol/L of ferrous ion, and 2.0 mmol/L of hydrogen peroxide after 10min. However, the change of COD in aqueous solution was not obvious and further study about intermediate products during oxidation process should be carried out in the future.

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