In-depth analysis of the removal mechanisms behind neonicotinoid pesticides and bimetal ZIF derived-magnetic carbon

Abstract

Emerging organic contaminants, such as pesticides, pose significant environmental challenges and necessitate the development of advanced materials and technologies for their efficient removal. This study explored various morphologies of bimetal ZIF-derived magnetic carbon for the removal of three representative neonicotinoid pesticides from water. Among the materials investigated, Co-NP3-1000, carbonized at 1000℃ from Zn/Co-ZIF with a Zn/Co molar ratio of 3:1, demonstrated outstanding adsorption performance, even in the presence of varying water chemistry parameters (e.g., humic acid and particulate matter), and effectively removed neonicotinoid pesticides at low concentrations from diverse actual water samples. Due to its strong magnetic properties, Co-NP3-1000 could be easily separated from solutions and maintained over 70% adsorption efficiency after five consecutive cycles. Moreover, Co-NP3-1000 exhibited high efficiency in removing other neonicotinoid pesticides (i.e., acetamiprid, nitenpyram, and thiamethoxam). Microstructure analysis and density functional theory calculation identified pore filling, hydrogen bonding, and π-π interactions as the primary forces driving NEOs adsorption. Notably, the relative contribution of these interactions was quantitatively assessed across different solution pH levels, and their sequence was elucidated using two-dimensional Fourier transform infrared correlation spectroscopy. This work advances both the design of versatile materials for the removal of emerging organic contaminants and quantitative insights into the interaction mechanisms between advanced adsorbents and these contaminants.