Department of Chemical Engineering, Lund University, Lund SE-221 00, Sweden.
Department of Chemical Engineering, Lund University, Lund SE-221 00, Sweden; Sweden Water Research AB, Ideon Science Park, Scheelevägen 15, Lund SE-223 70, Sweden.
Water Res. 2022 Aug 1;221:118738. doi: 10.1016/j.watres.2022.118738. Epub 2022 Jun 11.
Ozonation transformation products (OTPs) are largely unknown compounds that are formed during the ozonation of micropollutants, and it is uncertain to which extent these compounds can be removed by subsequent adsorption to activated carbon. Thus, C-labeled micropollutants were ozonated to generate C-labeled OTPs, for which the adsorption of the sum of all C-labeled OTPs to activated carbon could be determined, based on the adsorption of the labeled carbon. Further, CO traps were used to examine the mineralization of C-labeled moieties during ozonation. CO-formation revealed a partial mineralization of the C-labeled moieties in all compounds except for propyl-labeled bisphenol A and O-methyl-labeled naproxen. A similar degree of mineralization was noted for different compounds labeled at the same moiety, including the carboxylic carbon in diclofenac and ibuprofen (∼40% at 1 g O/g DOC) and the aniline ring in sulfamethoxazole and sulfadiazine (∼30% at 1 g O/g DOC). Aromatic ring cleavage was also confirmed for bisphenol A, sulfamethoxazole, and sulfadiazine through the formation of CO. The adsorption experiments demonstrated increased adsorption of micropollutants to powdered activated carbon after ozonation, which was connected to a decreased adsorption of dissolved organic matter (DOM). Conversely, the OTPs showed a substantial and successive decline in adsorption at increased ozone doses for all compounds, likely due to decreased hydrophobicity and aromaticity of the OTPs. These findings indicate that adsorption to activated carbon alone is not a viable removal method for a wide range of ozonation transformation products.
臭氧化转化产物（OTPs）是在微污染物臭氧化过程中形成的大量未知化合物，尚不确定这些化合物在多大程度上可以通过随后的活性炭吸附去除。因此，用 C 标记的微污染物进行臭氧化，生成 C 标记的 OTPs，可以根据标记碳的吸附来确定所有 C 标记的 OTPs 到活性炭的吸附。此外，还使用 CO 阱来检查臭氧化过程中 C 标记部分的矿化。CO 的形成表明，除了丙基标记的双酚 A 和 O-甲基标记的萘普生外，所有化合物中的 C 标记部分都有部分矿化。在不同的化合物中标记相同的部分时，也观察到了类似程度的矿化，包括在二氯芬酸和布洛芬中的羧酸碳（DOC 为 1 g O/g 时约为 40%）和磺胺甲恶唑和磺胺嘧啶中的苯胺环（DOC 为 1 g O/g 时约为 30%）。通过 CO 的形成还证实了双酚 A、磺胺甲恶唑和磺胺嘧啶的芳香环裂解。吸附实验表明，臭氧化后，粉末状活性炭对微污染物的吸附增加，这与溶解有机物（DOM）吸附减少有关。相反，对于所有化合物，随着臭氧剂量的增加，OTPs 的吸附都呈现出显著且连续的下降，这可能是由于 OTPs 的疏水性和芳香性降低。这些发现表明，仅靠活性炭吸附不是去除各种臭氧化转化产物的可行方法。
