Butachlor (BTR) degradation by dielectric barrier discharge plasma in soil: Affecting factors, degradation route, and toxicity assessment

Abstract

Over the past few decades, the frequent and excessive usage of pesticides has had detrimental effects on the soil and other habitats. In terms of removing organic contaminants from soil, non-thermal plasma has become one of the most competitive advanced oxidation methods. The study used dielectric barrier discharge (DBD) plasma to repair soil contaminated by butachlor (BTR). BTR degradation was investigated in actual soil under various experimental parameters. According to the results, DBD plasma treatment at 34.8 W destroyed 96.10% of BTR within 50 min, and this degradation was consistent with the model of first order kinetics. Boosting the discharge power, lowering the initial BTR concentration, using appropriate soil moisture content and air flow rate, and using oxygen as the working gas for discharge are all beneficial to the degradation of BTR. The changes in soil dissolved organic matter (DOM) before and after plasma treatment were assessed using a total organic carbon (TOC) analyzer. A Fourier transform infrared (FTIR) spectroscopy and an Ultra Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS) were employed to investigate the degradation of BTR. A wheat growth test showed that the best growth was achieved at 20 min of plasma soil remediation, but too long treatment would lower soil pH and thus affect wheat growth.