ZIF-8 as Potential Pesticide Adsorbent Medium for Wastewater Treatment: The Case Study of Model Linuron Extraction Conditions Optimization via Design of Experiment

The increasing presence of pesticide residues in aquatic environments poses a significant threat to ecosystems and human health, necessitating the development of effective removal technologies. In this study, Zeolitic Imidazolate Framework-8 (ZIF-8) was investigated as adsorbent for Linuron, a widely used herbicide. The material was synthesized via a hydrothermal method and underwent thorough physico-chemical characterization, confirming its intrinsic properties. Adsorption experiments were conducted under systematically varied conditions using a Central Composite Face-Centered (CFC) experimental design, evaluating the effects of temperature, Linuron concentration, ionic strength on adsorption efficiency. The Response Surface Methodology (RSM) revealed that temperature and Linuron concentration were the most influential variables. A quadratic effect of ionic strength and a significant interaction between Linuron concentration and ionic strength were also observed. The fitted quadratic regression model exhibited excellent predictive performance (R2 = 0.909; Q2 = 0.755), and analysis of variance (ANOVA) confirmed its significance (p < 0.001) with a non-significant lack of fit. Maximum Linuron removal (>95%) was achieved at elevated temperature, moderate concentration, and intermediate ionic strength. These findings highlight the potential of ZIF-8 as a tunable and high-efficiency adsorbent for the remediation of pesticide-contaminated water, demonstrating the value of RSM-based optimization in designing adsorption processes.