Hypochlorite-mediated degradation and detoxification of sulfathiazole in aqueous solution and soil slurry

Longhui Qiu; Caixia Yan; Yue Zhang; Yabing Chen; Minghua Nie

doi:10.1016/j.envpol.2024.124039

Hypochlorite-mediated degradation and detoxification of sulfathiazole in aqueous solution and soil slurry

Environ Pollut. 2024 Apr 24:350:124039. doi: 10.1016/j.envpol.2024.124039. Online ahead of print.

Authors

Longhui Qiu¹, Caixia Yan¹, Yue Zhang¹, Yabing Chen¹, Minghua Nie²

Affiliations

¹ School of Geography and Environment, Key Laboratory of Poyang Lake Wetland and Watershed Research, Ministry of Education, Jiangxi Normal University, Nanchang, 330022, China.
² School of Geography and Environment, Key Laboratory of Poyang Lake Wetland and Watershed Research, Ministry of Education, Jiangxi Normal University, Nanchang, 330022, China. Electronic address: mhnie@jxnu.edu.cn.

PMID: 38670426
DOI: 10.1016/j.envpol.2024.124039

Abstract

Although various activated sodium hypochlorite (NaClO) systems were proven to be promising strategies for recalcitrant organics treatment, the direct interaction between NaClO and pollutants without explicit activation is quite limited. In this work, a revolutionary approach to degrade sulfathiazole (STZ) in aqueous and soil slurry by single NaClO without any activator was proposed. The results demonstrated that 100% and 94.11% of STZ could be degraded by 0.025 mM and 5 mM NaClO in water and soil slurry, respectively. The elimination of STZ was shown to involve superoxide anion (O₂^•-), chlorine oxygen radical (ClO•), and hydroxyl radical (•OH), according to quenching experiments and the analysis of electron paramagnetic resonance. The addition of Cl^-, HCO₃^-, SO₄^2-, and humic acid (HA) marginally impeded the decomposition of STZ, while NO₃^-, Fe³⁺, and Mn²⁺ facilitated the process. The NaClO process exhibited significant removal effectiveness at a neutral initial pH. Moreover, the NaClO facilitated application in various soil samples and water matrices, and the procedure was also successful in effectively eliminating a range of sulfonamides. The suggested NaClO degradation mechanism of STZ was based on the observed intermediates, and the majority of the products exhibited lower ecotoxicity than STZ. Besides, the experiment results by using X-ray diffraction (XRD) and a fourier transform infrared spectrometer (FTIR) indicated the negligible effects on the composition and structure of soil by the treatment of NaClO. Simultaneously, the experimental results also illustrated that the bioavailability of heavy metals and the physiochemical characteristics of the soil before and after the remediation did not change to a significant extent. Following the remediation of NaClO, the phytotoxicity tests showed reduced toxicity to wheat and cucumber seeds. As a result, treating soil and water contaminated with STZ by using NaClO was a reasonably practical and eco-friendly method.

Keywords: Pathway; Phytotoxicity; Sodium hypochlorite; Soil remediation; Sulfonamides.