Synthesis and applications of porphyrin-based MOFs in removal of pesticide from wastewater: molecular simulations and experimental studies

Abstract

The high toxicity of pesticides to the ecosystem and humans has made their removal from water urgent. However, the properties of the insecticide made it challenging to complete the removal process with high adsorption capacity and exceptional selectivity. Biocompatible porphyrin-based MOFs with good adsorption capacity make them the best choice for removing methomyl pesticides from wastewater due to their large surface area and high porosity. In this work, iron-porphyrin-based MOFs (Fe-TCPP), zinc-porphyrin-based MOFs (Zn-TCPP) and copper-porphyrin-based MOFs (Cu-TCPP) were synthesized and investigated to remove methomyl from water. Besides the characterization of porphyrin-based MOFs with PXRD, FTIR, and FESEM, Langmuir and Freundlich isotherm models were used to describe adsorption behavior. Fe-TCPP showed a higher adsorption capacity (Q_m) than Zn-TCPP and Cu-TCPP, and the Q_m values for Fe-TCPP, Zn-TCPP and Cu-TCPP equal 270.07 mg g⁻¹, 190.97 mg g⁻¹, and 175.95 mg g⁻¹, respectively. Monte Carlo and molecular dynamic simulations were used to study the adsorption mechanism. The computational investigation indicates that the methomyl molecules are aggregated inside the MOF cavities and form hydrogen bonds between the methomyl pesticide and MOF structure.