SiO₂-modified MIL-53 for enhanced adsorption of chlorpyriphos from aqueous solutions: Synthesis, characterization, and mechanistic insights

Chlorpyriphos an organophosphorus pesticide, is readily absorbed through the skin of humans and poses the serious risk. In present study the surface modification of Fe-based metal organic framework (MIL-153) was carried out with silica for studying its efficiency toward adsorptive removal of Chlorpyriphos. For studying the physico-chemical properties of MIL-53/SiO₂ composite various characterization techniques like FTIR, BET, FE-SEM, EDS, XRD, and PSA were utilized. The effect of most significant parameters was optimized, and maximum removal of 60% was observed at pH 6. The monolayer adsorption onto energetically equivalent sorption sites described the chlorpyriphos capture by MIL-53/SiO₂. The maximum adsorptive capacity obtained by the non-linear Langmuir model was 58.5 mg chlorpyriphos per g MIL-53/SiO₂. Additionally, the kinetic models revealed the dependence of rate on the adsorptive capacity of adsorbent.