Cheap arsenic water filter developed by Pakistani scientists using watermelon rind


Scientists at the University of Agriculture Faisalabad (UAF) have developed a new technology to filter arsenic out of polluted water using watermelon rind, a local news outlet reported.

The cost-effective technology was developed after examining natural biowastes for arsenic removal after which it was discovered that chemically modified “xanted watermelon rind” is effective in catching arsenic which is usually found in abundance in groundwater. This method proved to remove 95 per cent of arsenic in polluted water.

The filter is developed by first washing watermelon rind to remove dirt. It is then heated to dry in sunlight and oven. The dried rind is then turned into powder in an electric grinder. Xanthated watermelon rind’s next phase is a fine example of chemistry as the powder is treated with sulfuric acid, which opens the biopolymer rings of the material and exposes many surface functional groups for reaction. The UAF team then treated it with Carbon disulfide – as sulfide has a unique quality to bind arsenic from water and the xanthated watermelon filter material is almost ready.

Speaking to a local news outlet, Dr Nabeel Khan Niazi, the supervisor of the research, said that the filter would cost around Rs5,000 to Rs6,000 whereas other filters cost around Rs20,000 to Rs25,000.

Dr Niazi is currently filing the patent for the filter and aims to widely distribute the invention among the marginalised people, who are living without electricity in rural areas of Pakistan as the filter works without using a power supply. He also submitted a proposal for funding to scale up the product via the Technology Development Fund of the Higher Education Commission (HEC).

Arsenic is a metalloid element, which forms a number of poisonous compounds. It is widely distributed throughout the earth’s crust and is found in groundwater supplies in a number of countries. Soluble inorganic arsenic is acutely toxic. Long exposure to arsenic-polluted water is lethal and claims the lives of 43,000 people annually. Arsenic pollution is common in Pakistan, China, India, Bangladesh, Nepal and some parts of the Americas.

Although there are many filters clean arsenic from groundwater, those methods are costly. The method discovered by Pakistani scientists is the cheapest so far.