Adsorption and effective removal of organophosphorus pesticides from aqueous solution via novel metal-organic framework: Adsorption isotherms, kinetics, and optimization via Box-Behnken design

The purpose of this study was to examine the efficiency of a tin-metal organic framework (Sn-MOF) to remove the organophosphate pesticide diazinon (DZ) from water. The results of the experiments conducted were compelling and demonstrated that Sn-MOF is a powerful adsorbent for removing DZ from aqueous solutions. The Sn-MOF was analyzed using various techniques including SEM, XRD, and BET analysis. It showed that the surface area of Sn-MOF is considerable high 897.69.75 m2/g and a significant pore volume of 1.04 cm3/g. Surface characterization was performed to determine the point of zero charge. To investigate the impact of pH levels on adsorption equilibrium, we carried out batch tests. Interestingly, our findings indicate that variations in solution pH have a significant impact on adsorption behavior. The optimum condition to have high adsorption capacity was found at pH 6, dose 0.01 g, and the temperature, as the temperature rises, the adsorption capacity rises because the process of adsorption is endothermic. The efficacy of DZ adsorption on Sn-MOF was extensively evaluated using kinetic models, specifically adhering to the pseudo-second-order model. Additionally, the Langmuir isotherm model was applied to accurately fit the adsorption process. It was observed that the overall process involved a chemisorption mechanism. In order to optimize the parameters such as absorbent dosage, solution pH, temperature, and time, Box-Behnken design (BBD) with Response Surface Methodology (RSM) was employed. Following the instructions, we were able to extract the values of (ΔH°), (ΔS°), and (ΔG°) for DZ, which indicated that the process was endothermic and spontaneous when using Sn-MOF as an adsorbent. The Sn-MOF adsorbent that was synthesized shows remarkable reusability and can be cycled up to five times for adsorption-desorption processes. The newly developed adsorbent's efficiency was evaluated as a proof of concept for purifying wastewater samples on a small scale in a laboratory. Additional study was done to better understand the way that Sn-MOF and DZ interact, and it was suggested that the interaction may occur through various mechanisms, including π-π interaction, pore filling, H-bonding, or electrostatic interaction. The use of Sn-MOF as an adsorbent presents a simple and effective approach for the treatment of industrial wastewater and water filtration. The effectiveness of utilizing Sn-MOF as an adsorbent to remove DZ from wastewater samples has never been demonstrated before, but our study is the first to do so. According to the results, a pH value of 6 is required to achieve the highest adsorption capability of DZ onto Sn-MOF, with a value of 587.39 mg.g−1.