Red mud based binder: A sustainable material for removal of chromium (VI) from water

Presence of chromium (VI) or Cr (VI) in the environment leads to its bioaccumulation and disruption of metabolic activity in living beings. Contaminated water is one of the main source of Cr (VI) into the living systems. Though different approaches for its removal have been investigated, a sustainable, cost effective and efficient method still remains a challenge. Red mud is an industrial waste from aluminum extraction process and is found to contain 40% of iron. According to past investigations, naturally occurring materials rich in iron have shown affinity to heavy metals and high binding stability. In the present study we have investigated red mud based geopolymer binder for removal of Cr (VI) from water. According to past studies, red mud geopolymer binder is difficult to cure at ambient temperature. Hence GGBS (ground granulated blast furnace slag) was added to the red mud in the geopolymer binder. The percentage of red mud in the binder was taken as 40%. In order to be used for practical applications, any material used for water purification should have a good strength and durability. Compression test of the geopolymer binder using processed red mud has shown an improvement in its mechanical property which includes strength. Investigation on removal of Cr (VI) as dichromate salt by adsorption by the red mud based binder was done by spectral analysis using UV-Vis spectrophotometer. 1,5-diphenylcarbazide was used to observe change in concentration of Cr (VI) as it forms a red violet colored complex with Cr (VI). A decrease in intensity with increase in time of contact between the red mud binder and dichromate solution was observed. The developed material has a potential to be used for removal of Cr (VI) from water. (C) 2020 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Advances in Material Science and Chemistry - 2020.