How to purify water with waste materials
Sand, coral and even waste building materials can become extremely efficient sorbents for water purification from toxic substances (e.x. arsenic), if they are subject to treat in a special way. Scientists of Tomsk Polytechnic University (TPU) have revealed a new technology during experiments. In practice, they succeeded to purify at least 18,000 glasses (3,6 m3) of water with the help of 200 grams of sorbent from the available raw materials, the cost of which will be a little more $1 to end consumers.
"Arsenic in drinking water is a huge problem for many countries across the world: India, China, USA, Argentina, Chile, Poland, Hungary and others. In Russia, arsenic containing regions are the Trans-Baikal, Khabarovsk, Perm, Stavropol, Magadan, Penza regions, Dagestan and Tuva republics.
Our technology allows any country to find the cheapest material to produce sorbents.
This may be a Vietnamese sand, corals, one can use sand, waste from the production of bricks, aerated concrete," – says the project's scientific supervisor Mikhail Khaskelberg, a leading engineer of the 12 Lab of the Institute of High Technology Physics, TPU.
According to him, for the experiments in the laboratory they use a solution in which the arsenic concentration was up to 50 times higher than the standards set by the World Health Organization.
"Yes, scientists in different countries are studying the same corals and sand as sorbents. But we succeeded in making these simple materials to work very effectively, using simple and inexpensive processes in terms of future production," — says Mikhail Khaskelberg.
Thus, the scientists use chemical adsorption resulting in contaminant deposition on the sorbent surface. The laboratory use electrokinetic adsorption, in which the positively charged heavy metal ions are attracted to the negatively charged surface of a sorbent.
"This technology can be used for purification of private wells water and waste industrial water, — the scientist said. — According to our calculations, one glass sorbent should be enough for at least 60-90 days, and if there is catastrophically much arsenic in water.
Furthermore, our sorbent can be regenerated at least 10 times. Moreover, if a leading Bayer sorbent Bayoxide® E 33 on the market costs about $ 27 per kg, our technology can do sorbent by cost at $ 4-5 per kg. It is clear that it is not necessary "to fill in" a filter with only our sorbent. One needs only some part, the rest volume can be safely filled with any known sorbent — one gets a high quality filter with a wide range of applications."
The scientists have already submitted an application for patenting the technology. They are also looking for Russian and foreign investors to introduce their development.
"Despite the fact that the purification of water using sorbents is not a pioneering discovery, the relevance of this subject is exceptional. Monthly top international journals published articles of serious scientists about the properties of the already known and some new materials. And this is understandable, the technology is improved, and problems are solved more elegantly. The basic idea is to develop the cheapest and most effective material. That is why the search is to be continued," — adds Mikhail Khaskelberg.