ARSENIC could be removed from contaminated drinking water or mining waste using just sunlight and air, according to researchers in Australia.
Arsenic contamination of drinking water is a major problem in many countries, such as India, Thailand and Mexico. In some of its affected areas, the Indian government issues chlorine tablets to add to the water. The tablets oxidise the highly toxic arsenic(III) to the less harmful arsenic(V), which can then be precipitated out using iron to form iron arsenate. But the use of chlorine generates chloroform, which is itself a dangerous chemical.
Now a team of scientists working with the Cooperative Research Centre for Waste Management and Pollution Control in Sydney say that the arsenic can be converted to its less dangerous form simply by exposing the water to sunlight and aerating it. The ultraviolet radiation in sunlight helps the dissolved oxygen to oxidise the arsenic to the ...
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