Sunlight mediated removal of chlorophenols over tungsten supported ZnO: Electrochemical and photocatalytic studies

Aslam, M.; Soomro, M. Tahir; Ismail, Iqbal M.I.; Salah, Numan; Gondal, M.A.; Hameed, Abdul

doi:10.1016/j.jece.2015.07.004

Cited by 23 publications

(7 citation statements)

References 54 publications

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“…A significant decrease in the reduction peak current depicted the decreased release of Zn(OH) 4 2-(zincate ion) in the solution due to the surface coating. The estimation of the suppression of the photocorrosion of ZnO, under illumination, by cyclic voltammetry, is well established [55,56].…”

Section: Photocatalytic Removal Of Chloro-acetic Acid Derivativesmentioning

confidence: 99%

MoO3 altered ZnO: A suitable choice for the photocatalytic removal of chloro-acetic acids in natural sunlight exposure

Qamar

Aslam

Rehan

et al. 2017

Chemical Engineering Journal

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The MoO 3 coated ZnO photocatalysts were synthesized for the optimum harvesting of the absorbed ultraviolet sunlight photons by initially permeating Mo 6+ ions at the surface of presynthesized ZnO and finally transformed to MoO 3 by thermal treatment in the air. The absorption spectra of the synthesized powders revealed the extension of the absorption edge in the visible region whereas, the photoluminescence spectroscopy established the supporting role of the MoO 3 coating in gradually plummeting the excitons recombination. The growth of additional peaks in Raman as well as x-ray photoelectron spectra and the appearance of the corresponding low-intensity reflection substantiated the surface prevalence of MoO 3. The absence of the individual particles of MoO 3 in FESEM and the verification of coated layer by HRTEM images validated the authenticity of the adopted synthetic route. The electrochemical evaluation of the synthesized powders under illumination revealed the complete elimination of photocorrosion and the synergic role of the MoO 3 layer for improved trap and transfer of charge carriers. The evaluation of the flat-band potentials of the coated powders by Mott-Schottky analysis revealed the suitability of the conduction band edges for the generation of superoxide anion radicals. The photocatalytic activity of the synthesized powders was assessed for the removal of chloro derivatives (mono-, di-, trichloroacetic acids) in comparison to pure acetic acid. A significant effect of the stability, polarity and stereochemical structure of the substrate on the photocatalytic removal process was observed and discussed. The experimental evidences from the timescale chemical analysis were interpreted for the identification of the reactive oxygen species (ROS) involved in the degradation/mineralization process. The validation of the Langmuir-Hinshelwood kinetic model was also examined. Efforts were made to estimate the plausible route of the degradation/mineralization process.

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Section: Photocatalytic Removal Of Chloro-acetic Acid Derivativesmentioning

confidence: 99%

MoO3 altered ZnO: A suitable choice for the photocatalytic removal of chloro-acetic acids in natural sunlight exposure

Qamar

Aslam

Rehan

et al. 2017

Chemical Engineering Journal

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“…Photocatalysis is one of the advanced oxidation photochemical processes that is the most efficient nonselective chemical pollutant removal technology [13]. Various studies have been conducted on the application of photocatalysis in the treatment of PCP, its salts (notably sodium pentachlorophenate (PCP-Na) and other chlorophenols [2,8,10,14,15,16]. Most findings are in agreement that this technology is effective at removing most organic pollutants in aqueous mediums.…”

Section: Introductionmentioning

confidence: 97%

“…Pentachlorophenol (PCP) is the highest chloride-substituted phenolic compound, its widespread use was based on its highly effective biocide properties and wood preservation [4,[7][8][9]. PCP has a high toxicity and is resistant to biological degradation processes, for this reason conventional water and wastewater treatment technologies are unable to remove or treat chlorophenols when dissolved in aqueous systems [10][11][12]. One type of technology that has been developed to treat these class of compounds is advanced oxidation processes (AOPs).…”

Section: Introductionmentioning

confidence: 99%

The impact of alkali metal halide electron donor complexes in the photocatalytic degradation of pentachlorophenol

Khuzwayo

Chirwa

2017

Journal of Hazardous Materials

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“…Chlorophenols are a large group of chemicals with chlorine atoms (between one and five) attached to the phenolic structure, and totally 19 congeners exist (1). Chlorophenols (CPs) present a sizable fraction of overall organic chemical compounds annually produced and consumed by a number of industries, such as pesticides, pulp and paper, antiseptics, pharmaceuticals and dyes (2)(3)(4). As a result they can be frequently found in surface and ground waters, soil and industrial wastewaters.…”

Section: Introductionmentioning

confidence: 99%

Application of a Zero-Valente Iron-Per Sulfate System to Treat Petrochemical Wastewater With High-Total Dissolved Solids Containing Para-Chlorophenol

Ahmadpour

Yengejeh

2016

Jundishapur J Health Sci

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Background: Zero-valent iron (ZVI) can effectively activate persulfate (PS) generating free sulfate radicals (SO 4 •-), thereby presenting a promising technology to degrade recalcitrant organic contaminants such as para-chlorophenol (PCP) in wastewater. Objectives: The current study aimed to examine the feasibility and application of ZVI/PS system through batch experiments to degrade PCP of petrochemical effluent, which its treatment is included in The United States environmental protection agency (USEPA) priority pollutant list. Materials and Methods: Effects of dosages of ZVI (0.056-2.8 g/L), ZVI to PS molar ratio (0.1-5.0), PS concentration (2.5-25.0 mM/L), pH = (3.0-11.0), contact time (5-240 minutes), and ZVI reusability (three cycles) on PCP degradation were examined. Results: The results showed that the PCP degradation increased with an increase in ZVI dosage from 0.056 to 1.4 g/L, an increase in persulfate concentration from 2.5 to 15.0 mM/L, and an increase in ZVI to PS molar ratio from 0.1 to 2.5. The optimal initial pH for PCP removal was 5.0 and the maximum removal efficiency of 70% was achieved within 120 minutes. Moreover, the ZVI catalyst was reused until the third cycle to activate the persulfate and degrade PCP. However, the degradation efficiency of PCP gradually decreased to 51.7% when the ZVI reuse time increased. Conclusions: The results indicate that using ZVI/PS system is not an efficient enough method to treat petrochemical effluent, due to the complexity of petrochemical wastewater matrix and high-total dissolved solids (TDS) content, as well.

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Sunlight mediated removal of chlorophenols over tungsten supported ZnO: Electrochemical and photocatalytic studies

Cited by 23 publications

References 54 publications

MoO3 altered ZnO: A suitable choice for the photocatalytic removal of chloro-acetic acids in natural sunlight exposure

MoO3 altered ZnO: A suitable choice for the photocatalytic removal of chloro-acetic acids in natural sunlight exposure

The impact of alkali metal halide electron donor complexes in the photocatalytic degradation of pentachlorophenol

Application of a Zero-Valente Iron-Per Sulfate System to Treat Petrochemical Wastewater With High-Total Dissolved Solids Containing Para-Chlorophenol

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