Removal of total arsenic in simulated irrigation water using electrocoagulation

• Main Authors: Laohoo, Janelle Nathalie C., Vallar, Paul Nathan B.
• Format: text
• Language: English
• Published: Animo Repository 2015
• Subjects: Arsenic wastes; Soils—Heavy metal content; Electrocoagulation; Chemical Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/5535
• Institution: De La Salle University

Arsenic (As) is one of the most toxic substances in the environment. Reports show that there is arsenic contamination in rice paddy soils in the Philippines. Some of these areas are in Bae, Laguna (15.49 ppm), Milaor, Camarines Sur (9.23 ppm) and Sipalay City, Negros Occidental (11.44 ppm). Irrigation water in Bae, Laguna contained 17 ppb Arsenic which is higher than the World Health Organization (WHO) standard for agricultural water. These demonstrate the need to prevent Arsenic contamination into the soil and groundwater which could be deposited and absorbed in food crop. Electrocoagulation is an efficient method used to remove dissolved heavy metals, such as Arsenic, in water. The focus of the study was on the effects of current density (3.0, 12.3 and 28.8 A/m²), electrode distance (16, 25 and 34 mm) and flow rate (0.4, 1.0 and 2.0 L/min) on the removal of total Arsenic using bench-scale, 18-L, cylindrical, electrocoagulation phase. Experimental runs for both phases were conducted based on the Taguchi Design of Experiments. For the pre-electrocoagulation phase, results show that the initial concentration of Arsenic for electrocoagulation increased with increasing flowrate. Among the parameters, it was found out that the electrode distance had the best correlation with an R² value of 0.9894 and a P-value of 0.547. For the electrocoagulation phase, a current density of 3 A/m², electrode distance 34 mm, and flow rate of 2 L/min gave the best electrocoagulation rate which gave an Arsenic removal of ˃95%.