在饮用水源受蓝藻水华影响期间,藻类代谢会产生大量藻类有机物(AOM),AOM易与氯消毒剂反应生成消毒副产物(DBPs),对供水水质和饮用水安全构成威胁。本研究以紫外(UV)、真空紫外(VUV)、过硫酸盐(PS)和紫外/过硫酸盐(UV/PS)等工艺为对照组,探究了真空紫外/过硫酸盐(VUV/PS)工艺在去除AOM和减少DBPs生成方面的效能与机理。实验结果表明,VUV/PS工艺去除AOM的效能优于对照工艺,DOC和UV254的去除率分别达74.7 %和70.7 %,荧光有机物的去除率也超过82.2 %。此外,AOM的去除效果随PS投加量的增加和溶液初始pH值的降低而增强。自由基探针实验进一步证实,VUV/PS工艺中的主要活性氧化物种(ROS)为羟基自由基和硫酸根自由基,测得二者的稳态浓度分别为4.78 × 10-13^和1.51 × 10-11 ^M-1^。VUV/PS工艺通过VUV光解与ROS的氧化作用共同实现了AOM的高效去除,且VUV有效促进了ROS的生成与转化。在后续氯消毒过程中,经过VUV/PS处理的AOM所生成的DBPs总量及其理论毒性显著下降。因此,VUV/PS工艺在富含AOM的水源水处理中展现出广阔的应用前景。

Algal blooms in drinking water sources produce a large amount of algal organic matter (AOM), and AOM can react with chlorine to produce disinfection by-products (DBPs), significantly endangering the water quality. Thus, the vacuum ultraviolet/persulfate (VUV/PS) process was employed to remove AOM and reduce the disinfection by-products (DBPs) formation. The VUV/PS process demonstrated superior efficiency in AOM removal compared to UV/PS, VUV, UV, and PS processes, achieving removal rates of dissolved organic carbon (DOC) and UV254 at 74.7 % and 70.7 %, respectively. Additionally, the removal rate of fluorescent organic matter surpasses 82.2 %. The PS dose and initial pH impacted AOM removal by influencing the transformation and concentration of reactive oxygen species (ROS). The primary ROS in VUV/PS process was hydroxyl radicals (HO?^{) and sulfate radicals (}SO4??^{), with steady-state concentrations of} 4.78 × 10-13 and 1.51 × 10-11 ^M-1^, respectively. AOM was effectively eliminated by VUV photolysis and ROS oxidation, with VUV enhancing the efficiency of AOM removal by facilitating the generation and conversion of ROS. Additionally, during subsequent chlorination, VUV/PS process significantly reduced the yield of DBPs and the theoretical toxicity. In conclusion, VUV/PS process exhibited significant potential for application in treating AOM-rich water.

X524

国家自然科学基金(51878090)