Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, 510275, PR China.
Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, 510275, PR China.
Water Res. 2019 Mar 1;150:77-85. doi: 10.1016/j.watres.2018.11.041. Epub 2018 Nov 19.
The solar/chlorine process produces multiple reactive species by solar photolysis of chlorine, which can be used as an energy-efficient technology for water treatment. This study investigated the effects of pH and dissolved oxygen (DO) on the degradation of pharmaceuticals and personal care products (PPCPs) and on the formation of disinfection byproducts (DBPs) in the solar/chlorine system. The degradation of 24 structurally diverse PPCPs was enhanced appreciably in the solar/chlorine system compared to solar irradiation and dark chlorination. The reactive species in the solar/chlorine system were identified to be hydroxyl radicals (HO), reactive chlorine species (RCS, i.e., Cl and ClO) and ozone. With increasing pH from 6 to 8, the steady-state concentrations of HO and Cl decreased from 1.23 × 10 M to 4.79 × 10 M and from 9.80 × 10 M to 4.31 × 10 M, respectively, whereas that of ClO increased from 5.30 × 10 M to 2.68 × 10 M and the exposure of ozone increased from 0.44 μM min to 1.01 μM min in 90 min. Accordingly, the removal efficiencies of 6 PPCPs decreased and 11 PPCPs increased. The decreased removal of PPCPs with increasing pH was due to the decrease in HO and Cl, while the increased removal was attributed to the increased ClO and ozone. The presence of DO enhanced the degradation of most PPCPs, indicating the role of ozone on the degradation. The formation of total organic chlorine (TOCl) and known DBPs was enhanced by 60.7% and 159.4%, respectively, in the solar/chlorine system compared to chlorination in a simulated drinking water containing 2.5 mg L natural organic matter (NOM). As the pH rose from 6 to 8, TOCl formation decreased by 16.2%, while that of known DBPs increased by 58.6% in solar/chlorine. The absence of DO slightly suppressed the formation of TOCl and known DBPs. This study illustrated the significant role of RCS in the solar/chlorine system, which enhanced the degradation of micropollutants but increased the formation of chlorinated DBPs.
太阳光/氯工艺通过太阳光解氯产生多种反应性物种，可作为一种用于水处理的节能技术。本研究考察了 pH 值和溶解氧 (DO) 对太阳能/氯系统中药物和个人护理产品 (PPCP) 的降解和消毒副产物 (DBP) 形成的影响。与太阳光照射和暗氯化相比，24 种结构多样的 PPCP 在太阳光/氯系统中的降解得到了显著增强。在太阳光/氯系统中，反应性物种被鉴定为羟基自由基 (HO)、反应性氯物种 (RCS，即 Cl 和 ClO) 和臭氧。随着 pH 值从 6 增加到 8，HO 和 Cl 的稳态浓度分别从 1.23×10-5 M 降至 4.79×10-5 M 和从 9.80×10-5 M 降至 4.31×10-5 M，而 ClO 的浓度从 5.30×10-5 M 增加到 2.68×10-5 M，臭氧的暴露量从 90 分钟内的 0.44 μM·min 增加到 1.01 μM·min。相应地，6 种 PPCP 的去除效率降低，11 种 PPCP 的去除效率增加。随着 pH 值的增加，PPCP 的去除率降低是由于 HO 和 Cl 的减少，而去除率的增加则归因于 ClO 和臭氧的增加。DO 的存在增强了大多数 PPCP 的降解，表明臭氧在降解中的作用。与含有 2.5mg·L 天然有机物 (NOM) 的模拟饮用水中的氯化相比，太阳光/氯系统中总有机氯 (TOCl) 和已知 DBP 的形成分别增加了 60.7%和 159.4%。当 pH 值从 6 升高到 8 时，TOCl 的形成减少了 16.2%，而在太阳光/氯系统中，已知 DBP 的形成增加了 58.6%。没有 DO 会稍微抑制 TOCl 和已知 DBP 的形成。本研究说明了 RCS 在太阳光/氯系统中的重要作用，它增强了污染物的降解，但增加了氯化 DBP 的形成。
