Gamma irradiation-induced decomposition of sulfamethoxazole in aqueous solution: the influence of additives, biological inhibitory, and degradation mechanisms

Abstract

Sulfamethoxazole (SMX) was decomposed by using gamma irradiation in the presence of different additives such as NO, NO, Cr(VI), 2-propanol, and tert-butanol. The results demonstrated that NO, NO, 2-propanol, and tert-butanol inhibited SMX radiolytic removal. However, there existed a synergetic effect for radiolytic removal of the mixture containing SMX and Cr(VI). At an absorbed dose of 150 Gy, the removal percentages of SMX and Cr(VI) in the mixture were 73.5 and 84.6%, respectively, which was higher than the removal percentages of 70.6 and 4.1% for the single component of SMX and Cr(VI). This provides us an insight into treating the combined pollution in micro-polluted water. The SMX radiolytic removal followed a pseudo first-order reaction kinetic model, and the rate constant ratios of ·OH, e, and H· towards SMX radiolysis were 10.4:1:2.9. In addition, 24-h bio-inhibitory to the macroalgae of SMX solution during gamma irradiation reached the maximum of 0.85 at an adsorbed dose of 100 Gy, then gradually decreased with the increasing adsorbed dose. Based on LC-MS analysis and quantum chemical calculation, the degradation intermediates were determined and concluded that SMX radiolytic removal was mainly via ·OH radical attack and direct decomposition of SMX molecule by gamma ray.

Application of Radiation Technology in Removing Endocrine Micropollutants from Waters and Wastewaters—A Review

“…As expected, the initial concentration of SMX has a significant effect on its rem efficiency [31]. The efficiency of the process depends on the initial concentration; a concentration increases, the efficiency decreases.…”

Fe(IV)═O/Fe(V)═O and [FeaqIVO]2+/[FeaqVO]3+ Cooperating with Free Radicals Induced High-Rate Sulfamethoxazole-Cr(VI) Simultaneous Removal in a Fe7S8-Persulfate Micro/Nanocatalytic System

“…These compounds enter groundwater through animal feces and seep. , Moreover, landfills play a crucial role as significant sources of SMX-Cr­(VI) combined pollution in groundwater . Additionally, diverse sources, including the pharmaceutical industries, electroplating plants, and aquaculture, introduce substantial quantities of SMX and Cr­(VI) into wastewater.…”