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 Remediation of Cr(VI)-Contaminated Soil by Nano-Zero-Valent Iron in Combination with Biochar or Humic Acid and the Consequences for Plant Performance

Toxics ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 26 ◽  
Author(s):  
Yuhuan Sun ◽  
Fangyuan Zheng ◽  
Wenjie Wang ◽  
Shuwu Zhang ◽  
Fayuan Wang
Keyword(s):  
Humic Acid ◽  
Plant Growth ◽  
Contaminated Soil ◽  
Crop Production ◽  
Agricultural Soils ◽  
Synergistic Effects ◽  
Zero Valent Iron ◽  
Plant Performance ◽  
High Dose ◽  
Nano Zero Valent Iron

Nano-scale zero-valent iron (nZVI) is among the most common nanoparticles widely used for the treatment of various environmental contaminants. However, little is known about the combined effects of nano-zero-valent iron (nZVI) and other soil amendments on soil remediation and plant performance. For the first time, we studied the remediation of Cr(VI)-contaminated soil using bare nZVI (B-nZVI) and starch-supported nZVI (S-nZVI) in combination with either biochar (BC) or humic acid (HA), and the consequent effects on plant growth and Cr accumulation. Both S-nZVI and B-nZVI decreased the contents of Cr(VI) and available Cr in soil, but increased available Fe content, with S-nZVI generally showing more pronounced effects at a higher dose (1000 mg/kg). B-nZVI exerted no inhibition and even stimulation on plant growth, but 1000 mg/kg S-nZVI produced significant phytotoxicity, resulting in decreased plant growth, low chlorophyll content in leaves, and excessive accumulation of Fe in roots. Each nZVI decreased shoot and root Cr concentrations. BC and HA produced synergistic effects with nZVI on Cr(VI) removal from soil, but HA decreased soil pH and increased the availability of Cr and Fe, implying a potential environmental risk. Addition of BC or HA did not alter the effects of either nZVI on plant growth. In conclusion, combined application of 100 mg/kg nZVI and BC could be an ideal strategy for the remediation of soil contaminated with Cr(VI), whereas high-dose S-nZVI and HA are not recommended in the remediation of agricultural soils for crop production or in the phytostabilization of Cr(VI).

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.

Isomer-Specific Assay of Ester and Salt Formulations of 2,4-Dichlorophenoxyacetic Acid by Automated High Pressure Liquid Chromatography

1977 ◽  
Vol 60 (4) ◽  
pp. 868-872
Author(s):  
Norman E Skelly ◽  
Timothy S Stevens ◽  
David A Mapes
Keyword(s):  
High Pressure ◽  
Internal Standard ◽  
Dichlorophenoxyacetic Acid ◽  
Precision Data ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Liquid Chromatographic ◽  
Better Than

Abstract An automated high pressure liquid chromatographic method is described for the assay of 2,4-dichlorophenoxyacetic acid (2,4-D) in either salt or ester herbicide formulations. The method is specific for the 2,4-D isomer, and resolves all known impurities from 2,4-D and the internal standard. Ester products are assayed similarly to salt formulations, following room temperature in situ saponification. Results are thus obtained for all products as a per cent 2,4-D acid equivalent. Compounds are separated on a reverse phase microparticulate column with acetonitrile-water (20+80), buffered at pH 3. Precision data indicate a relative standard deviation of better than 1%. The method was developed to replace the nonspecific total chlorine, titration, and saponification assay procedures.

Study on the Collaborative Degradation of Acid Red B Dye Wastewater by O3/H2O2

2014 ◽  
Vol 1010-1012 ◽  
pp. 872-875
Author(s):  
Hai Feng Chen
Keyword(s):  
Hydrogen Peroxide ◽  
Gas Flow ◽  
Reaction Rate ◽  
Ph Value ◽  
Good Effect ◽  
Dye Wastewater ◽  
Gas Flow Rate ◽  
Reaction Conditions ◽  
Decoloration Rate ◽  
Better Than

Acid Red B dye wastewater was collaborative degradated by ozone and hydrogen peroxide. Various reaction conditions are studied which affect on decoloration rates of wastewater. The decoloration rate of Wastewater increases with O3 gas flow rate increasing, and also increases with pH value increasing. O3/H2O2 collaborative effects are better than O3 alone, and the decoloration rate is higher with more H2O2 addition. Ozone Oxidation have a good effect to degrade Acid Red B dye wastewater, the decoloration rate can reach 98% with inflating O3 30min. H2O2 synergy can greatly increase the reaction rate, shorten the reaction time, improve the utilization of ozone.

Effects of growth regulators and controlled atmosphere on stored carrots

1974 ◽  
Vol 82 (2) ◽  
pp. 245-249 ◽  
Author(s):  
M. Abdel-Rahman ◽  
F. M. R. Isenberg
Keyword(s):  
Gibberellic Acid ◽  
Growth Regulators ◽  
Dichlorophenoxyacetic Acid ◽  
Trimethylammonium Chloride ◽  
Controlled Atmosphere ◽  
Benzyl Adenine ◽  
Large Size ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Better Than

SummaryPreharvest sprays with 6-hydroxy-3-(2H)-pyridazinone (MH), or immersion in solutions of MH, 2,4-dichlorophenoxyacetic acid (2,4-D), 2-chloroethylphosphonic acid (ethephon), coumarin or (2-chloroethyl) trimethylammonium chloride (CCC) inhibited both sprouting and rooting of treated carrots during storage at 0 °C whencompared with water-dipped or untreated carrots, while N-6-benzyl-adenine (BA) dips stimulated extensive rooting and sprouting. In contrast, immersion in gibberellic acid (GA3) solutions had very little effect.Storage atmospheres containing 1, 2.5, 5 or 10% oxygen inhibited both sprouting and rooting but increased mould infection. Atmospheres containing 21% (air) or 40% oxygen reduced mould infection, but increased sprouting and rooting of stored carrots. Washing carrots in water before storage did not significantly affect mould infection, while washing in 0.5% clorox increased it. However, washing in water followed by immersion in MH inhibited both sprouting and rooting and also reduced mould infection. ‘Jumbo’ and large-size carrots stored better than medium and small carrots.

scholarly journals One-Pot Synthesis of TiO2-rGO Photocatalysts for the Degradation of Groundwater Pollutants

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 5938
Author(s):  
Stefano Andrea Balsamo ◽  
Roberto Fiorenza ◽  
Marcello Condorelli ◽  
Roberta Pecoraro ◽  
Maria Violetta Brundo ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Textural Properties ◽  
Degradation Process ◽  
Solar Irradiation ◽  
Dichlorophenoxyacetic Acid ◽  
One Pot ◽  
Promising Strategy ◽  
Reduced Graphene ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Green Procedure

A non-conventional approach to prepare titanium dioxide-reduced graphene oxide (TiO2-rGO) nanocomposites based on solar photoreduction is here presented. The standard hydro-solvothermal synthesis of the TiO2-rGO composites requires high temperatures and several steps, whereas the proposed one-pot preparation allows one to obtain the photocatalysts with a simple and green procedure, by exploiting the photocatalytic properties of titania activated by the solar irradiation. The TiO2-rGO catalysts were tested in the solar photodegradation of a widely adopted toxic herbicide (2,4-Dichlorophenoxyacetic acid, 2,4-D), obtaining the 97% of degradation after 3 h of irradiation. The as-prepared TiO2-rGO composites were more active compared to the same photocatalysts prepared through the conventional thermal route. The structural, optical, and textural properties of the composites, determined by Raman, Photoluminescence, Fourier Transform InfraRed (FTIR), UV-vis diffuse reflectance (DRS) spectroscopies, and N2 absorption-desorption measurements, showed as the solar irradiation favors the reduction of graphene oxide with higher efficiency compared to the thermal-driven synthesis. Furthermore, the possible toxicity of the as-synthesized composites was measured exposing nauplii of microcrustacean Artemia sp. to solutions containing TiO2-rGO. The good results in the 2,4-D degradation process and the easiness of the TiO2-rGO synthesis allow to consider the proposed approach a promising strategy to obtain performing photocatalysts.

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