Abstract

The presence of organophosphorus pesticides and their residues in both aquatic and terrestrial ecosystems can cause many problems in the environment and human health. Therefore, it is necessary to intensify research into effective and efficient processes for removing pesticides from the environment. In the present study, an electrocoagulation process was used to remove diazinon (DZ) in the presence of a magnetic guar gum (MGG) as aid coagulant. In the first stage, guar gum was modified by three methods and the structural properties of MGG by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) were characterized. It was then optimized in the process of electrocoagulation using magnetic guar gum as the aid coagulant. Response surface methodology (RSM) was used to evaluate the operating parameters to achieve the optimum condition for the treatment process. The model was well fitted to the actual data, and the correlation coefficients of R-2, adjusted R-2, and predicted R-2 were found as 0.9903, 0.9883, and 0.9826, respectively. Results showed that the removal efficiency of DZ by using the combination of FeCl3 and NH4Cl as adsorbents was lower than that of the single modification. Under the constant value center point of DZ concentration (17.5 mg.L-1), pH (7.0) and current density (5.25 mA cm(-2)), the removal efficiency of DZ was increased from 59.4 to 79.8 by increasing the dosage of MGG from 0.5 to 3 g L-1. However, the maximum removal efficiency (98.8) of DZ was achieved under optimal conditions including initial DZ dosage of 11.25 mg L-1, pH of 8.5, current density of 11.75 mA cm(-2), and MGG concentration of 2.38 mg L-1 upon 20 min reaction time.