title: Assessment of the UV/chlorine process as an advanced oxidation process.
abstract: Several organic compounds were used as radical scavengers/reagents to investigate the possibility of the UV/chlorine process being used as an advanced oxidation process (AOP) in the treatment of drinking water and wastewater. The UV/H(2)O(2) process was selected as a reference, so that the results from the UV/chlorine process could be compared with those of the UV/H(2)O(2) process. Methanol was added to active chlorine solutions at both pH 5 and 10 and into hydrogen peroxide samples. The photodegradation quantum yields and the OH radical production yield factors, which are significant in evaluating AOPs, were calculated for both the UV/chlorine and the UV/H(2)O(2) processes. The yield factor for the UV/chlorine process at pH 5 was 0.46 ± 0.09, which is much lower than that of the UV/H(2)O(2) process, which reached 0.85 ± 0.04. In addition to methanol, para-chlorobenzoic acid (pCBA) and cyclohexanoic acid (CHA) were added to active chlorine solutions and to H(2)O(2) solutions, to evaluate the efficiencies of oxidizing these organic compounds. The specific first-order reaction rate constants for the oxidation of pCBA and CHA, using the UV/chlorine process, were lower than those found using the UV/H(2)O(2) process.
authors.affiliation: Department of Civil and Environmental Engineering University of Alberta, Edmonton, AB, Canada.
authors.forename: Jing
authors.initials: J
authors.lastname: Jin
authors.forename: Mohamed Gamal
authors.initials: MG
authors.lastname: El-Din
authors.forename: James R
authors.initials: JR
authors.lastname: Bolton
mesh_terms: D002713:Chlorine / Q000737:chemistry*; D002723:Chlorobenzoates / Q000737:chemistry; D003509:Cyclohexanecarboxylic Acids / Q000737:chemistry; D005557:Formaldehyde / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical / Q000737:chemistry; D007700:Kinetics; D000432:Methanol / Q000032:analysis; D010084:Oxidation-Reduction; D011789:Quantum Theory; D014466:Ultraviolet Rays; D018508:Water Purification / Q000379:methods*
chemical_list: D002723:Chlorobenzoates; D003509:Cyclohexanecarboxylic Acids; D005557:Formaldehyde; D017665:Hydroxyl Radical; D002713:Chlorine; D006861:Hydrogen Peroxide; C040768:4-chlorobenzoic acid; D000432:Methanol