Varanasi, April 2 : The scientists of IIT-BHU have developed a system to extract toxic substances from water by using ash made from teak and neem wood. This method is not only eco-friendly, but also inexpensive and can also be adopted to purify Ganga water besides reducing the cost of ROs while retaining the available minerals in the water. Vishal Mishra, an assistant professor of biochemical engineering, and his team have prepared two different types of adsorbent from the ashes of teak wood sawdust and neem stalk, thereby, separating the harmful metals, ions from the water that can be made potable. He said that in recent years, adsorption has been considered inexpensive and more effective than other chemical techniques. It costs less and is considered very effective in the prevention of water borne diseases. Mishra said that the wood powder of teak (scientific name: Tectona grandis) is mixed with sodium thiosulfate and heated in an atmosphere of nitrogen to make activated charcoal. Also, adsorbent is also made from neem (scientific name: Azadirachta Indica) and stalk ash (neem twig ash). On one hand, the teak can extract harmful gases, ions, sulphur, selenium in water from coal made of wood, and, on the other, the study of neem ash is intended for the treatment of polluted water containing copper, nickel and zinc. He pointed out that many researchers in the world have already investigated available porous (perforated / extremely small holes) charcoal as an active agent, but their method of chemical synthesis involves several drawbacks. Porous charcoal made from sawdust wood powder is harmless and eco-friendly. Sodium thiosulfate is not a toxic reagent (a chemical substance helps in the discovery of other substances). It has many medicinal applications. On the other hand, neem seeds, bark and leaves have been used as an adsorbent by various researchers but neem stalk ashes have not been used for purity of water. He said that the nickel present in water is responsible for asthma, neuro disorder, nausea, kidney and lung cancer. Zinc causes fatigue, lethargy, dizziness and excessive thirst while the excess copper in the water is genotoxic, which can cause changes in DNA and also damage the liver and kidneys. According to him, this method can also be adopted to purify Ganga water. The Ganga is rich in nickel, zinc and copper. Packed Bed Column (PBC) method in Ganga is made clean with the help of ETP (Efficient Treatment Plant). In these ETPs, initiatives can be taken to clean Ganga water very cheaply, using coal made from teak wood and ash made from Neem stalks. He said that it may also reduce the cost of RO being sold in the market. Currently RO systems are installed in almost every household. Coal made from teak wood sawdust can be used to purify water in place of the activated charcoal in the RO system. This will also reduce the total cost of RO and the available minerals in the water will be safe. /IANS