Arsenic contamination of drinking water is a global issue, The maximum concentration of allowable arsenic is 10 Parts per Billion as per WHO (World Health Organization) Standards. Arsenic is distributed throughout the earth's crust. In some areas, safe drinking water may not be possible, or may be very expensive. Arsenic removal is the only solution to this issue.
Arsenic is introduced into water through the dissolution of minerals and ores, Concentrations in groundwater in some areas are higher due to erosion from arsenic rich rocks, industrial effluents contribute to arsenic concentrations in some areas, as well as Combustion of fossil fuels is a source of arsenic in the environment through disperse atmospheric deposition. Finally, arsenic occurs in the environment in several forms, in natural waters it is mostly found as trivalent arsenite or pentavalent arsenate. Organic arsenic species, abundant in seafood, are very much less harmful to health, and are readily eliminated by the body.
Drinking-water represent the highest threat to public health from arsenic. Exposure at work and mining and industrial emissions may also be significant.
Arsenic Removal Technologies:
All of the technologies for arsenic removal rely on a few basic processes, as follows:
Reactions that reduce or oxidize, altering the chemical forms of Arsenic.
Causes dissolved arsenic to form a low-soluble solid mineral that can be removed through filtration.
Ion Exchange Adsorption:
Involve the reversible displacement of an ion adsorbed onto a solid surface by a dissolved ion.
Synthetic Membranes are permeable to certain dissolved compounds and exclude others, these membranes elements can act as a molecular filters to remove dissolves arsenic along with other dissolves solids.
AA Adsorption is a physical/chemical process by which ions in solution are removed by the available adsorption sites on an oxide surface. AA is used primarily in packed beds to remove contaminants such as fluoride, arsenic, selenium, silica, and natural organic matters.
Simple Technologies for household removal of arsenic are limited. Reverse osmosis have proven to be an efficient solution for arsenic removal.