Batch Adsorption Studies Incorporating Response Surface Methodology for the Elimination of Acephate

[摘要] Banned pesticides are continuously preferred by the planters of the Idukki District irrespective of their toxicity. Among the banned pesticides, acephate is preferred because of its high solubility in water and persistent character. Unfortunately, it detriments the biota, leading to neurogenic, carcinogenic, and physiological disorders in fish. The plantation near the Periyar River basin is contaminated with residues of pesticides, which eventually drain into the river. There is an urgent need for the removal of acephate. Therefore, we have focused on the removal of acephate into the lab scale. Batch adsorption studies were carried out for the removal of acephate. We selected a material Fe-MMT (Fe3O4-montmorillonite), which is benign and possesses a high adsorption capacity towards acephate. Adsorbent properties were examined by various analytical tools XRD, SEM, FTIR, and a Surface area analyzer. Adsorption followed Langmuir with first-order kinetic. Kinetic plots exhibited multistage adsorption, indicating film diffusion and pore diffusion during the adsorption or the mechanism of adsorption is chemisorption, physisorption, and Lewis’s acid-base interaction. Response surface methodology involving CCD (central composite design) was extracted to maximize the adsorption of acephate onto Fe-MMT. Dosage and concentration seem to be the major parameters that influenced the adsorption. Adsorption achieved a peak (83.18%) at optimum conditions corresponding to pH 6, initial acephate concentration of 2 mg/L, and adsorbent dosage corresponding to 0.5 g/L.

[关键词] acephate;magnetically modified montmorillonite;multistage adsorption;response surface methodology