Effective degradation of DELTA pesticide in soil by an atmospheric-pressure cold plasma-DBD system

Abstract

In protecting crops and increasing yields, the usage of pesticides, such as deltamethrin (DELTA), has increased due to rising worldwide food demand. However, the toxicity of DELTA, its limited biodegradability, and persistence are causing harm to the environment and also human health. There exist conventional soil remediation methods, but they are either costly, slow, or may cause secondary pollution, prompting interest in greener solutions. Atmospheric-pressure Cold Plasma (ACP) produced by dielectric barrier discharge (DBD) can offer an eco-friendly and innovative method for remediating pesticide-contaminated soil. In this study, an ACP-DBD plasma source was designed and developed and employed for the degradation of DELTA in soil. Cocopeat was used as a model soil to simulate field conditions. The effects of key operational parameters such as frequency, discharge voltage, treatment time, various pesticide concentrations, cocopeat soil pH and moisture were systematically evaluated to determine optimal conditions for maximum degradation efficiency. The onsite generation of reactive oxygen and nitrogen species within soil pores facilitated the effective degradation of DELTA, achieving removal efficiencies of up to 84.8% under optimized operational parameters. The detailed FTIR and GC-MS analysis further identified distinct degradation intermediates, supporting a mechanistic pathway predominantly driven by hydroxyl radicals and singlet oxygen (1O2). These findings are consistent with established plasma chemistry and underscore the oxidative transformation routes underlying pesticide breakdown. The results also highlight the potential of ACP-DBD as a green and effective technology for remediating pesticide-contaminated soils.