Halide-specific enhancement of photodegradation for sulfadiazine in estuarine waters: Roles of halogen radicals and main water constituents

Photodegradation of sulfadiazine in different aquatic environments – Evaluation of influencing factors

“…Halide scavenging may dramatically reduce the treatment efficiency of electron-poor contaminants that react slowly with RHS, but the extent of the reduction with electron-rich contaminants may be less remarkable (Grebel et al, 2010). Zhao et al (2019) demonstrated that RHS were largely responsible for the halide-specific enhancement in the SDZ photodegradation, rather than other reactive species, such as 3 DOM * and ˙OH. These findings are in agreement with those observed in this work but different from those obtained by other authors, which pointed out the absence of significant effects of ionic species (Conde-Cid et al, 2018) or the inhibitory effect of salinity on the photocatalytic degradation of sulfonamide antibiotics (Oliveira et al, 2019;Yang et al, 2015).…”

“…Their incomplete removal in sewage treatment plants (STPs) accounts for the occurrence of these compounds in effluents from STPs and receiving waters (Oliveira et al, 2019). Even at relative low concentrations, their presence in the aquatic environment is of severe concern because of the induction of bacterial resistance (Zhao et al, 2019), which is actually considered a major threat to global health by the World Health Organization (WHO, 2019).…”

“…, 1 O 2 , peroxyl radicals (ROO . ), excited triplet states of dissolved organic matter ( 3 DOM * )) (Carlos et al, 2012;Silva et al, 2016a;Yi et al, 2018;Zhao et al, 2019) capable of causing the phototransformation of SDZ. In any case, these processes can be noticeably impacted by the characteristics of the aquatic medium and, therefore, for an appropriate assessment of the environmental fate and risks of SDZ, it is necessary to understand matrix effects on its photodegradation.…”

“…Indeed, seawater DOM has already shown to have higher reactivity than freshwater DOM on the photodegradation of sulfonamides (Wang et al, 2018). Along with DOM, halide ions were found responsible for the larger SDZ photodegradation in estuarine than in freshwaters by Zhao et al (2019), who highlighted that antibiotics photodegradation from freshwaters downstream into seawater is largely unknown. Contrarily, Conde-Cid et al (2018) did not find a significant influence of ionic species (including the halide Cl -) on the photodegradation of SDZ.…”

Effects of dissolved organic matter on photochemicaltransformation of organic micropollutants in natural waters

“…Figure 6 Quenching effect of antioxidants on redox reactions between 3 DOM* and pollutants 根据式(2)计算抑制因子(IF): [114,115] 、卤素自由基 [101] 等. 因此, DOM 对OMPs光降解的影响与水中卤素离子等盐度离子有 关. Zhao等人 [116] Zhou等人 [119] 发展的模型在光强变化预测方面具…”