Novel Nano-approach for remediation of arsenic contaminated water



They published their findings online in ACS Nano recently.

Arsenic is a natural element found widely in the earth\’s crust. It may be found in some drinking water supplies, including wells. Millions of people, mostly in Bangladesh and India, continue to suffer from drinking water that contains dangerously high levels of arsenic. It causes cancer of the skin, bladder, lungs and kidneys.

Despite the fact that scientists have made great progress in understanding how, where and why arsenic ends up in soil and water, and have designed promising tests and filters, straightforward solutions to the arsenic problem that affects hundreds of millions of people have, so far, been hard to come by.

Previous research have shown that Arsenic can be removed from drinking water by using activated carbon or precipitating it out with iron minerals, such as iron oxides – for example magnetite (Fe3O4) nanocrystals. However, such particles cannot be used in rivers, or other environments where water flows, because of their small size and the fact that magnetite rapidly oxidises when exposed to the atmosphere.

To overcome this problem, lead researcher Kwang Kim, Director of Center for Superfunctional Materials at Korea-based Pohang University of Science and Technology and colleagues, have synthesized a new type of magnetite composite by combining magnetite (Fe3O4) nanocrystals with carbon and carbon nanotubes, and graphene-based materials such as graphene oxide.

\”This is in many ways the simplest, cheapest and most effective method for large scale production of reduced graphene oxide (RGO)-Fe3O4 composite and remediation of arsenic polluted water. The presence of graphene sheets among magnetite particles increases adsorption sites and stability of Fe3O4 nanoparticles\”, Kim told

Graphene is new 2-dimensional material and there is no report for arsenic removal from water using graphene based materials. The composite can be used in flowing water and steady water. Neither graphene oxide nor Fe3O4 is harmful for health

Nan Pan at Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, welcomed the new development saying to \”It is very impressive and interesting, and of great importance to the environmental conservation aspects.\”

\”As far as I know, the RGO is light-weight, flexible, (almost) nontoxic, low-cost, and can be mass-produced and easily processed with macro-size, a hybrid nanomaterial based on RGO should have a great potential to be applied practically.\”

\”However, the time of putting it into practice & market is still hard to assess now.\”

Chuanlai Xu at School of Food Science and Technology of China-based Jiangnan University, disagreed with Pan about the practicality of the new approach.

\”Since the composites have shown near complete (over 99.9%) arsenic removal within one part per billion [the usual safety limit for arsenic in water is ten parts per billion], So only several months may be possible to achieve a practical solution.\” Xu told

\”The practical device may contain permanent or electro magnetite, container and mixing apparatus which can not be very complicated. The size will depend on the volume of water to deal with. Thus the device will not be very expensive and may be used by ordinary people for its simple operation. However, Sometimes the water contains unknown concentration of arsenic and the removal condition may be different for different water sources in practical separation, thus the device can be developed with certain apparatus as detector to confirm the water quality after removal.\”, Xu explained.

Speaking to, Jiaxing Huang, Assistant Professor of Materials Science & Engineering at US-Based Northwestern University whose team\’s findings about the fire safety during graphite oxide/graphene production are published online in Advanced Functional Materials., said \” This work looks quite interesting. It uses reduced graphene oxide as the carrier for magnetite nanoparticles for removing toxic arsenic ions from water.\”

\”As water purification is crucial for our heath and sustainable development, I will be glad to see graphene based materials becoming more useful for this purpose.\”, Huang concluded.