Removal of Nitrate from Simulated Groundwater using Chitosan as Coagulant Aid in Electrocoagulation Process

Nitrate contamination on groundwater has been an increasing global concern particularly in industrialized and developing nations. This study investigates the efficiency of electrocoagulation for nitrate removal from simulated groundwater, with chitosan applied as a natural coagulant aid. The process used aluminum as electrodes at constant agitation speed of 260 rpm, inter-electrode distance of 10 mm, 2.5 ppm chitosan and initial nitrate concentration of 39 ppm. The effects of pH, applied voltage, and operation time were systematically evaluated. Optimal conditions—pH 2, 30 V, and 90 min—achieved a nitrate removal efficiency of 98.14 %, a substantial improvement over the 73.99 % removal observed under similar conditions without chitosan. The significant increase in removal efficiency at lower pH values can be attributed to the increased protonation of chitosan and the increased formation of positive aluminum hydroxide complexes which improved coagulation. Moreover, higher voltage enhanced current density, promoting faster electrode dissolution and metal hydroxide generation. Statistical analysis via ANOVA confirmed the significant influence of all independent variables (pH: p = 2.12 x10-8; voltage: p = 2.51 x 10-6; operation time: p = 5.20 x10-5). These findings demonstrate that the combined use of electrocoagulation and chitosan offers a highly effective and synergistic approach for nitrate remediation in groundwater which is aligned with sustainable development goal 6: clean water and sanitation.