Indian scientists develop nanomaterial to treat wastewater
Ateam of researchers led by Dr. Ramavatar Meena at the Central
Salt and Marine Chemicals Research Institute, Bhavnagar, India, have created carbon-based cleaning process fully green by using seaweeds as starting material. They have synthesised graphene-iron sulfide nanocomposite from abundantly found seaweed — Ulva fasciata – through direct pyrolysis technique.
Seaweeds are known as carbon sinks. In some earlier studies, biomass of Ulva fasciata has been directly employed for adsorbing copper and zinc ions from water but the uptake capacities were relatively low. This problem was resolved by deriving thin carbon sheets from seaweed at very high temperature. These graphene sheets were doped with iron. The nanocomposite obtained from seaweed showed a very high adsorption capacity for various cationic and anionic dyes as well as lead and chromium.
The nanocomposite can be used in up to eight cleaning cycles, with only nominal loss of its adsorption capacity. Even mixed dyes could also be adsorbed. A maximum adsorption capacity of 645 mg per gram for lead was achieved at neutral pH. This is the highest ever reported for any biomass derived carbon material, scientists have claimed in their study published in Journal of Hazardous Materials. It could also remove highly toxic hexavalent chromium from wastewater.