Enhanced arsenic removal from drinking water by electrocoagulation: Influence of anode material and ultrafine bubbles

Abstract

Arsenic (As) contamination of drinking water is a critical global public health concern, particularly in low- and middle-income regions where monitoring and treatment remain limited. Although the World Health Organization (WHO) guideline for As in drinking water is 10 μg/L, many rural systems still rely on outdated standards or lack treatment facilities. Ultrafine bubble (UFB) technology has recently been proposed to enhance contaminant removal. In this study, conventional electrocoagulation (EC) was combined with UFB water to evaluate As removal, comparing three anode materials (aluminum, iron, zinc) under varied pH conditions and treatment times. Batch EC experiments were conducted using a synthetic As solution (300 μg/L) prepared in either deionized (DI) or UFB water. Removal efficiency, energy consumption, and anode dissolution were systematically assessed. Iron anodes combined with UFB achieved the highest performance, removing ∼99 % of As within 10 min and reducing residual concentrations below the WHO guideline (≤10 μg/L). Zinc anodes performed well under alkaline conditions, whereas aluminum showed the lowest efficiency (30 % removal after 30 min). Energy consumption was lowest for Fe (0.13 kWh/m 3 ), with both energy consumption and anode dissolution slightly reduced when UFB was applied. The improved performance is attributed to enhanced gas–liquid mass transfer, reactive oxygen species generation, and more efficient coagulation/flotation dynamics. These findings highlight the potential of EC–UFB integration as a low-cost, energy-efficient strategy for As remediation in small-scale and rural water treatment systems. Future work should focus on pilot-scale validation with real groundwater, long-term electrode stability, sludge management, and cost–benefit assessment to support practical implementation.