Treatment of Arsenite Contaminated Water By Electrochemical Techniques (Paperback)
The world is inclining towards sustainable development. The sustainable development goal no. 6 aims to achieve universal and equitable access to safe and affordable drinking water for all by 2030. World Health Organization (WHO) emphasizes that drinking water should be devoid of the highest priority chemical parameters, including fluoride and arsenic (As). The removal of arsenic from the water matrix is critical due to its carcinogenic effects.
Arsenic is released in various environmental compartments (air, water, soil)
through natural as well as anthropogenic activities such as the manufacturing of cement, mining activity, fossil fuel burning, and production of paper. The presence of As in drinking water through groundwater contamination increases its concentration and exposure time in the human body, leading to severe health effects . According to (WHO) standards, the maximum permissible level of arsenic in drinking water is 0.010 mg L-1, followed by most developed countries, including Bangladesh. In India, 0.050 mg L-1 is considered the accepted level for arsenic in drinking water. Arsenic, one among the 'Big Four' nonessential toxic elements (As, Hg, Cd,
and Pb), shows complex metabolism. WHO classified arsenic in group 1 human carcinogenic list, as it is the most abundant and potential human carcinogen in the environment. It is estimated that lifetime exposure to 50 g L-1 of arsenic- containing water may lead to a
cancer risk of 1 in 100. The toxicity of various arsenic species is in the order: arsenite (As3+) > arsenate (As5+) > monomethyl arsenate > dimethyl arsenate. In the more mobile and soluble form, inorganic arsenic is more harmful to human health than organic due to its higher cytotoxic and genotoxic nature. Once arsenic enters the human body, it can cause extreme damages to normal body functions and impacts nearly all organ systems (central nervous system, respiratory, cardiovascular, gastrointestinal, immune, reproductive systems, and so on).
The electrochemical treatment process has significant considerations in recent times due to its flexibility and environmental compatibility. Electrochemical techniques are an alternative to the electrochemical and chemical responses in the electrochemical cell, which leads to the treatment of liquid, gas, and solids conceivable.
Electrochemical methods are categorized into two groups' separation methods and oxidation methods. Separation methods are again classified into three types such as electro-sorption, electrodialysis, and electrocoagulation. Electro- sorption is the advanced process of adsorption in which potentially-induced adsorption on the surface of charged electrodes by supplying current to electrodes.
Electrodialysis is the process in which the removal of ions by using selective
ion or semi-permeable membranes under the influence of an electric field, the current supply to the electrodes (where oxidation/reduction occurs), and oxidized ions are passed through membranes; providing transport of counter ions and blockage of co- ions. Ribeiro et al. studied the removal of arsenic by electrodialysis method using platinized titanium bars and untrained removal of 99% for 30 days duration.