Investigation of COD Removal for the Glyphosate Herbicide from Aqueous Solution by Electrocoagulation Process

Abstract

This study investigated the glyphosate adsorption by water treatment residual using the method of indirect Chemical Oxygen Demand (COD) in aqueous solution using the electrocoagulation process. The optimum glyphosate removal was obtained with typical operating conditions: initial pH of 5.8, initial herbicide concentration of 100 mg/L, current density 25 mA/cm2, type of electrolyte, and salt concentration of 1 g/L and temperature of 20oC. The results showed that the COD of glyphosate removal were 89.8% by using iron (Fe) electrodes at 40 min, 89.8% by using stainless steel S-S at 60 min, while were 84.8 % by using aluminum Al electrodes at the 80 min. It was found that the data fitted to Freundlich (R2 = 0.964) model. In glyphosate the electrocoagulation process can be described by a pseudo first order with rate constant (0.0059, 0.0052 and 0.005 min- 1) by using Fe, S-S and Al electrodes respectively. The consumption of electrical energy for glyphosate at optimum conditions as follows: (9.999, 13.9 and 19.0619 KWh/m3) using Fe, S-S and Al electrodes respectively. Keywords: Electrocoagulation; Electrodes; Herbicide; Glyphosate; Adsorption; Kinetics