title: Degradation of pentachlorophenol by hydroxyl radicals and sulfate radicals using electrochemical activation of peroxomonosulfate, peroxodisulfate and hydrogen peroxide.
abstract: The present study is to investigate the reactivity of free radicals (SO4(-) and HO) generated from common oxidants (peroxomonosulfate (PMS), peroxodisulfate (PDS) and hydrogen peroxide (HP)) activated by electrochemically generated Fe(2+)/Fe(3+) ions which furthermore are evaluated to destroy pentachlorophenol (PCP) in aqueous solution. The effect of solution pH and amount of oxidants (PMS, PDS and HP) in electrocoagulation (EC) on PCP degradation is analyzed in detail. The experimental results reveal that, optimum initial solution pH is 4.5 and PMS is more efficient oxidant addition in EC. 75% PCP degradation is achieved at 60min electrolysis time from PMS assisted EC. According to the first order rate constant, faster PCP degradation rate is obtained by PMS assisted EC. The PCP degradation rate by oxidant assisted EC is observed in the following order: EC/PMS>EC/PDS>EC/HP>EC. Further to identify the influences of experimental factors involved in PCP degradation by oxidant assisted EC, an experimental design based on an orthogonal array (OA) L9 (3(3)) is proposed using Taguchi method. The factors that most significantly affect the process robustness are identified as A (oxidant) and B (pH) which together account for nearly 86% of the variance.
authors.affiliation: Water Research Laboratory, Water Institute, Karunya University, Coimbatore 641114, Tamil Nadu, India. Electronic address: govindanmu@gmail.com.
authors.forename: Kadarkarai
authors.initials: K
authors.lastname: Govindan
authors.affiliation: Centre for Research in Materials Sciences and Thermal Management, Karunya School of Mechanical Sciences, Karunya University, Coimbatore 641114, Tamil Nadu, India; Department of Biotechnology, Karunya University, Coimbatore 641114, Tamil Nadu, India.
authors.forename: Mohan
authors.initials: M
authors.lastname: Raja
authors.affiliation: Water Research Laboratory, Water Institute, Karunya University, Coimbatore 641114, Tamil Nadu, India.
authors.forename: Michael
authors.initials: M
authors.lastname: Noel
authors.affiliation: Water Research Laboratory, Water Institute, Karunya University, Coimbatore 641114, Tamil Nadu, India.
authors.forename: E J
authors.initials: EJ
authors.lastname: James
mesh_terms: D000704:Analysis of Variance; D004563:Electrochemistry / Q000379:methods*; D004572:Electrolysis; D052918:Environmental Restoration and Remediation; D006861:Hydrogen Peroxide / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical; D016877:Oxidants / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry; D010416:Pentachlorophenol / Q000737:chemistry*; D010545:Peroxides / Q000737:chemistry*; D017680:Potassium Compounds / Q000737:chemistry*; D013431:Sulfates / Q000737:chemistry*; D014874:Water Pollutants, Chemical
chemical_list: D016877:Oxidants; D010545:Peroxides; D017680:Potassium Compounds; D013431:Sulfates; D014874:Water Pollutants, Chemical; C069025:sulfate radical; C038288:peroxymonosulfate; D017665:Hydroxyl Radical; C009007:potassium persulfate; D006861:Hydrogen Peroxide; D010416:Pentachlorophenol; D010100:Oxygen
keywords: Fe electrode; Oxidant activation; Oxidants assisted electrocoagulation; Pentachlorophenol degradation; Taguchi analysis