Radical Chemistry and Structural Relationships of PPCP Degradation by UV/Chlorine Treatment in Simulated Drinking Water
Citations Over TimeTop 1% of 2017 papers
Abstract
The UV/chlorine process is an emerging advanced oxidation process (AOP) used for the degradation of micropollutants. However, the radical chemistry of this AOP is largely unknown for the degradation of numerous structurally diverse micropollutants in water matrices of varying quality. These issues were addressed by grouping 34 pharmaceuticals and personal care products (PPCPs) according to the radical chemistry of their degradation in the UV/chlorine process at practical PPCP concentrations (1 μg L-1) and in different water matrices. The contributions of HO• and reactive chlorine species (RCS), including Cl•, Cl2•-, and ClO•, to the degradation of different PPCPs were compound specific. RCS showed considerable reactivity with olefins and benzene derivatives, such as phenols, anilines, and alkyl-/alkoxybenzenes. A good linear relationship was found between the RCS reactivity and negative values of the Hammett ∑σp+ constant for aromatic PPCPs, indicating that electron-donating groups promote the attack of benzene derivatives by RCS. The contribution of HO•, but not necessarily RCS, to PPCP removal decreased with increasing pH. ClO• showed high reactivity with some PPCPs, such as carbamazepine, caffeine, and gemfibrozil, with second-order rate constants of 9.2 × 107, 1.03 × 108, and 4.16 × 108 M-1 s-1, respectively, which contributed to their degradation. Natural organic matter (NOM) induced significant scavenging of ClO• and greatly decreased the degradation of PPCPs that was attributable to ClO•, with a second-order rate constant of 4.5 × 104 (mg L-1)-1 s-1. Alkalinity inhibited the degradation of PPCPs that was primarily attacked by HO• and Cl• but had negligible effects on the degradation of PPCPs by ClO•. This is the first study on the reactivity of RCS, particularly ClO•, with structurally diverse PPCPs under simulated drinking water condition.
Related Papers
- → Comparison of the UV/chlorine and UV/H2O2 processes in the degradation of PPCPs in simulated drinking water and wastewater: Kinetics, radical mechanism and energy requirements(2018)411 cited
- → Removal of emerging micropollutants originating from pharmaceuticals and personal care products (PPCPs) in water and wastewater by advanced oxidation processes: A review(2021)253 cited
- → Sulfate radicals-based advanced oxidation processes for the degradation of pharmaceuticals and personal care products: A review on relevant activation mechanisms, performance, and perspectives(2022)252 cited
- → Occurrences of pharmaceuticals and personal care products in the drinking water of Taiwan and their removal in conventional water treatment processes(2020)99 cited
- → APPLICABILITY OF SULFATE RADICAL BASED ADVANCED OXIDATION PROCESSES FOR DRINKING WATER TREATMENT(2023)