Efficient degradation of imidacloprid by surface discharge cold plasma: Mechanism of interaction between ROS and molecular structure and evaluation of residual toxicity

• Published in: Journal of hazardous materials 2024-03, Vol.465, p.133066-133066, Article 133066
• Main Authors: Ni, Jia-Bao, Jia, Xiao-Fang, Zhang, Jun-Ying, Ding, Chang-Jiang, Tian, Wen-Li, Peng, Wen-Jun, Zielinska, Sara, Xiao, Hong-Wei, Fang, Xiao-Ming
• Format: Article
• Language: English
• Subjects: Cold plasma; Formation energy; Imidacloprid; Neonicotinoid pesticides; Reactive oxygen species
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2023.133066

Incorrect use of neonicotinoid pesticides poses a serious threat to human and pollinator health, as these substances are commonly present in bee products and even drinking water. To combat this threat, the study developed a new method of degrading the pesticide imidacloprid using surface discharge cold plasma oxidation technology. The study showed that this method achieved a very high efficiency of imidacloprid degradation of 91.4%. The main reactive oxygen species (H2O2, O3, ·OH, O2-, 1O2) effectively participated in the decomposition reaction of imidacloprid. Reactive oxygen species were more sensitive to the structure of the nitroimine group. Density functional theory (DFT) further explored the sites of reactive oxygen species attack on imidacloprid and revealed the process of energy change of attacking imidacloprid. In addition, a degradation pathway for imidacloprid was proposed, mainly involving reactive oxygen species chemisorption, a ring-opening intermediate, and complete cleavage of the nitroimine group structure. Model predictions indicated that acute oral and developmental toxicity were significantly reduced after cold plasma treatment, as confirmed by insect experiments. Animal experiments have shown that plasma treatment reduces imidacloprid damage to mice hippocampal tissue structure and inhibits the reduction of brain-derived neurotrophic factor content, thus revealing the detoxification mechanism of the body. [Display omitted] •A new energy-efficient method for discharge cold plasma degradation of imidacloprid is proposed.•91.4% of imidacloprid was removed in the cold plasma system within 40 min.•1O2, O2–and •OH generated in the cold plasma process contributed to imidacloprid decomposition.•The sensitive sites for ROS attack on imidacloprid molecules were predicted by DFT calculations.•Possible imidacloprid degradation pathways and toxicity assessment are proposed.