Removal of quinclorac herbicide in soil by FeS2@BC coupling with persulfate process: Soil constituent and phytotoxicity

Abstract

The significant accumulation of quinclorac in soil and its transport within the environment have grave implications for the growth and development of flora and fauna in natural ecosystems. This study marks the first instance of employing FeS2 loaded on biochar to activate PMS for direct degradation of QNC in soil. Experimental results show that the FeS2@BC/PMS system successfully removed 90.77% of QNC from contaminated soil after 6 h of reaction at 2 g/L FeS2@BC, 4 mM PMS, and 30 mg/kg QNC-polluted soil. The distribution of QNC in both water and soil phases before and after degradation indicated that QNC was desorbed from the soil and then degraded, and it was difficult to degrade directly from the soil surface. Soil component removal experiments showed that soil Fe/Mn minerals and organic matter acted synergistically and antagonistically during the degradation of QNC by the FeS2@BC/PMS system, respectively. Quenching experiments and ESR assays revealed that 1O2 was the main reactive oxygen species responsible for removing QNC. Seed germination and potting experiments showed that the FeS2@BC/PMS system effectively alleviated root deformity and reduced the growth inhibition of roots, stems, and leaves caused by QNC during mung bean seed germination and seedling growth. The results suggest that the FeS2@BC/PMS system can effectively remediate QNC-polluted soil, which may provide a reference for the remediation of organic contaminated soil.