Batch adsorption studies incorporating response surface methodology for the elimination of acephate

Banned pesticides are continuously preferred by the planters of the Idukki District irrespective of their toxicity. Among the banned ones acephate is preferred to 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 to Periyar River basin is contaminated with residues of pesticides and eventually drains to the river. There is an urgent need for the removal of acephate. So we have focused on the removal of acephate into the lab scale. Batch adsorption studies were carried onto the removal of acephate. We selected a material Fe-MMT ( Fe₃O₄-montmorillonite) which is benign and possess a high adsorption capacity towards acephate. Adsorbent properties were examined by various analytical tools XRD, SEM, FTIR, and 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 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 peak (83.18%) at optimum conditions corresponding to pH 6, initial acephate concentration 2mg/L, and adsorbent dosage corresponding to 0.5g/L.