Photocatalytic degradation of 4-amino-6-chlorobenzene-l,3- disulfonamide stable hydrolysis product of hydrochlorothiazide: Detection of intermediates and their toxicity

摘要

AbstractIn this work we have investigated in details the process of degradation of the 4-amino-6-chlorobenzene-1,3-disulfonamide (ABSA), stable hydrolysis product of frequently used pharmaceutical hydrochlorothiazide (HCTZ), as one of the most ubiquitous contaminants in the sewage water. The study encompassed investigation of degradation by hydrolysis, photolysis, and photocatalysis employing commercially available TiO2Degussa P25 catalyst. The process of direct photolysis and photocatalytic degradation were investigated under different type of lights. Detailed insights into the reactive properties of HCTZ and ABSA have been obtained by density functional theory calculations and molecular dynamics simulations. Specifically, preference of HCTZ towards hydrolysis was confirmed experimentally and explained using computational study. Results obtained in this study indicate very limited efficiency of hydrolytic and photolytic degradation in the case of ABSA, while photocatalytic degradation demonstrated great potential. Namely, after 240 min of photocatalytic degradation, 65% of ABSA was mineralizated in water/TiO2suspension under SSI, while the nitrogen was predominantly present asNH4+. Reaction intermediates were studied and a number of them were detected using LC-ESI-MS/MS. This study also involves toxicity assessment of HCTZ, ABSA, and their mixtures formed during the degradation processes towards mammalian cell lines (rat hepatoma, H-4-II-E, human colon adenocarcinoma, HT-29, and human fetal lung, MRC-5). Toxicity assessments showed that intermediates formed during the process of photocatalysis exerted only mild cell growth effects in selected cell lines, while direct photolysis did not affect cell growth.Graphical abstractDisplay OmittedHighlights•Detailed analysis of hydrolysis process of hydrochlorothiazide (HCTZ).•Direct photolysis of 4-amino-6-chlorobenzene-1,3-disulfonamide (ABSA).•Photocatalytic degradation of ABSA using TiO2Degussa P25.•LC-ESI-MS/MS detection of degradation intermediates of ABSA.•Toxicity of HCTZ, ABSA and its intermediates in mammalian cell lines.The degradation kinetics, mineralization, reaction intermediates and toxicity assessment of 4-amino-6-chlorobenzene-1,3-disulfonamide, stable hydrolysis product of hydrochlorothiazide.