UV/chlorine as an advanced oxidation process for the degradation of benzalkonium chloride: Synergistic effect, transformation products and toxicity evaluation

State of the Art of UV/Chlorine Advanced Oxidation Processes: Their Mechanism, Byproducts Formation, Process Variation, and Applications

“…benzalkonium chloride UV/chlorine 91% reduction by 2 h treatment lower than chlorination alone [53] luminescence inhibition (Q67) phenacetin UV/chlorine increase in inhibition (9 → 23%) by 20 min treatment, but lower than chlorination alone (45%) [54] respiration inhibition (Escherichia colli) 5,5-diphenylhydantoin UV/chlorine decrease to non-toxic level by 10 min treatment lower than chlorination alone [141] cytotoxicity (human hepatoma cells (Hep3B)) microcystin-LR UV/chlorine 7-37% increase in viability against UV or chlorination alone [142] Protein phosphatase inhibition assay microcystin-LR UV/chlorine 75.0% decrease for 10 min treatment [94] whole effluent toxicity (Ceriodaphnia dubia) trichloroethylene in groundwater UV/chlorine almost no toxicity [143] estrogenic activity (E-screen assay)…”

“…Chlorinated organic compounds like halomethanes (HMs), haloacetic acids (HAAs), haloacetonitriles (HANs), haloketones (HKs), halonitoromethanes (HNMs), haloacetamides (HAAms), and chloral hydrate (CH) are well known DBPs by chlorination [49,50] and their formation in UV/chlorine AOPs is thereby apprehended. In fact some researchers reported that UV/chlorine AOPs produced trichloromethane (TCM) and chloroform (CF) in HMs, dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) in HAAs, dichloroacetonitrile (DCAN) and trichloroacetonitrile (TCAN) in HANs, dichloropropanone (DCP) and trichloropropanone (TCP) in HKs, chloronitoromethane (CNM), dichloronitoromethane (DCNM), and trichloronitromethane (TCNM) in HNMs, dichloroacetamide (DCAAm) and trichloroacetamide (TCAAm) in HAAms, and CH [20][21][22]37,47,[51][52][53][54][55]. Some comparative studies of UV/chlorine process with chlorination have been reported.…”

“…Accordingly, the toxicity will increase with the formation of toxic byproducts. However, part of them are decomposed by a prolonged operation of UV/chlorine process [21,53,60], which will result in a decrease in toxicity. In fact, a temporal increase and following decrease in V. fischeri toxicity was observed in all researches where a negative effect of UV/chlorine treatment on the toxicity removal was reported [21,37,40].…”

“…Many researchers have observed that acidic pH is better for UV/chlorine AOPs on removing organic pollutants such as amitriptyline hydrochloride [75], benzalkonium chloride [53], caffeine [31], chloramphenicol [22], diethyltoluamide [31], 1,4-dioxane [5], iodoform [76], methyl salicylate [75], metronidazole [31], nalidixic acid [31], naproxen [40], neonicotinoid insecticides [74], nitrobenzene [77], 2-phenoxyethanol [75], ronidazole [78], and taste and odor compounds [79]. Three mechanisms, namely a change in quantum yield of chlorine photolysis, equilibrium shifts of radical species, and radical scavenger effects of HOCl and ClO − , are mainly responsible for the pH dependence of the performance of UV/chlorine AOPs.…”

Kinetics, Mechanism, and Toxicity of Amlodipine Degradation by the UV/Chlorine Process

“…A wide variety of PhACs (up to mg•L −1 ) have been found in soil [5,6], surface water [7], drinking water sources [8], and aquatic organisms [9] all over the world, including Asia, Europe, and USA [10][11][12][13]. Many studies have shown that PhACs can lead to numerous undesirable symptoms, such as developmental, endocrine, and reproductive disorders [14]. Therefore, the determination and regulation of PhACs in water has become a pressing problem to be resolved in many countries and regions.…”