Seaweed-derived graphene removes dyes, heavy metals
doi:10.1038/nindia.2018.43 Published online 12 April 2018
Researchers have synthesised a graphene-based nanocomposite from edible seaweed that can remove toxic dyes and heavy metals from contaminated water including industrial wastewater1.
Adsorbents made from seaweeds so far don’t efficiently remove dyes and heavy metals from wastewater. Besides, processes to make them are complex and require harmful chemicals.
In search of an eco-friendly technique to make a dye remover, scientists from the CSIR-Central Salt and Marine Chemicals Research Institute, in Gujarat, India, led by Ramavatar Meena prepared the nanocomposite from the seaweed using a one-step solvent-free process. They then tested its efficiency in removing dyes and heavy metals from various water samples that mimic contaminated wastewater and seawater.
The nanocomposite removed toxic dyes such as methylene blue, methyl orange, crystal violet and Congo red, and heavy metals such as lead and chromium from the water samples. The adsorbent could be reused up to eight times for removing dyes.
Salinity had negligible effect on the adsorbent’s ability to bind to dyes, making it an excellent dye remover. A commercial filter paper coated with a thin layer of the nanocomposite was then exposed to a flow of dye solution. The solution became colourless within five minutes, indicating that the dyes moved from the solution to the filter paper.
In the next phase of research, we are planning to develop a prototype filter using the nanocomposite that can be used for treating wastewater from textile and leather industries, says lead researcher Meena.
1. Mahto, A. et al. Solvent-free production of nano-FeS anchored graphene from Ulva fasciata: a scalable synthesis of super-adsorbent for lead, chromium and dyes. J. Hazard. Mater. (2018) doi:10.1016/j.jhazmat.2018.03.054