Choosing the most suitable electrode for drinking water treatment by electrochemical process

Electrochemical technology is an advanced oxidation processes (AOPs) in water treatment. Electrochemical efficiency is calculated based on consumed energy per kilogram of parameter removed that is the most important factor in electrochemical economics. The aim of this applied-analytical study is to choose the most suitable electrode for drinking water treatment by a batch electrochemical reactor with aluminum, copper, iron, and steel electrodes.

Samples of urban drinking water were introduced into an electrochemical reactor and the removal efficiency was studied as a function of time (5, 10, 20, and 40 min), electrode material (steel-iron, aluminium-aluminium, and copper-copper), and current density (0.01, 0.015, 0.02, and 0.03 mA/cm2). Electrochemical efficiency was calculated as consumed energy per Kilogram of removed parameter according to Faraday law. The concentration of sulfate, nitrate and calcium was determined according to 4500-SO42- E, 4500NO3- B and 3500Ca B methods. Water samples were tested with ethical considerations according to the Helsinki guidelines

Removal percentages of alkalinity, sulphate, nitrate, and calcium in 2 cm distance, current density 0.03 mA/cm2, and contact time 20 min using steel-iron, aluminium-aluminium, and copper-copper electrodes were 44.3%, 35%, 26.3%, and 50.6%; 26%, 18%, 36.8%, and 40.7%; 32.8%, 33%, 32.6%, and 34/5%, respectively. The highest removal efficiencies of sulfate, nitrate and calcium were obtained by copper-copper (61.2%), aluminum-aluminum (66.3%) and steel-iron electrodes (58%), respectively.

The findings indicate that removal efficiency of calcium, nitrate, and sulphate is increased with increasing voltage and time. The best conditions for removal in three pair electrodes are obtained to be electrolysis time 40 min and voltage 30 volt.