Recent Advances in Biomass-Based Waste Materials for the Removal of Chromium (VI) from Wastewater: A Review

Abstract

Hexavalent chromium (Cr(VI)) is a critical pollutant with high toxicity, even at trace concentrations. Cr(VI) is possibly carcinogenic and mutagenic and can produce serious health issues. Hence, it is necessary to remove Cr(VI) from the water before releasing it into the environment. Currently, numerous removal techniques were used. Adsorption is the best method compared to others because it is simple, cheap, highly efficient, and can be used in water having trace concentrations of contaminants. Biomass-based waste materials (BMWs) are found as far better adsorbents than commercially and other available adsorbents. In this study, the existing Cr(VI) removal techniques are reviewed and, a broad range of current research studies of Cr(VI) removal from water by using BMWs are evaluated. This review can be helpful to develop a more efficient, cheap, reliable, and environmentally benign bio-adsorbent. It is obvious after the literature review given herein that BMWs exhibited potential adsorbents for the removal of Cr(VI). Also, the chemically modified adsorbents exhibited a higher adsorption capacity than unmodified adsorbents.

Acid-treated pomegranate peel; An efficient biosorbent for the excision of hexavalent chromium from wastewater

“…In a basic medium, it forms CrO 4 2− ions whereas, in an acidic medium (pH 1 to 6), HCrO 4 − and Cr 2 O 7 2− ions are in equilibrium, HCrO 4 − being the most common species. At pH below 1, H 2 CrO 4 is the dominating species [ 24 , 42 , 52 ]. A very high positive redox potential for Cr (VI) in an acidic solution implies that it is strongly oxidizing in the presence of species that donate electrons.…”

“…Several methods are being studied and used to eliminate Cr(VI) from the aquatic environment, some of which are ion exchange [ 18 , 19 ], electro-dialysis [ 20 ], redox reaction, membrane technology [ 21 ], and adsorption [ [22] , [23] , [24] ]. Most of the aforementioned solutions can only be used to a certain extent due to the requirement for expensive equipment, incomplete metal removal, hazardous waste sludge, and disposal [ 16 , [25] , [26] , [27] ].…”

Efficient biosorption of hexavalent chromium from water by modified arecanut leaf sheath

“…Among all pollutants, heavy metals possess major worries due to their highly toxic, imperishable, and steady nature. Hexavalent chromium, cadmium (Cd), arsenic (As), mercury (Hg), nickel (Ni), cobalt (Co), etc are the major toxic heavy metal pollutants ( Rathore et al., 2017 ; Rai et al., 2021 ) and their pollution is not only detrimental to the surroundings, but they also further cause a serious problem for human health. Amidst harmful heavy metals, hexavalent chromium is examined as a major water toxin.…”

Efficient Sequestration of Cr(VI) from Aqueous Solution Using Biosorbent Derived from Arundo donax Stem

“…are the predominant type of ions in a basic media with a pH greater than 6.e ions HCrO 4 − and Cr 2 O 7 2− are in equilibrium in an acidic solution with a pH of 1 to 6, but HCrO 4 − is the main species[43,44]. Because the predominant form of Cr(VI) at pH 2 is HCrO 4 − , and the solution includes a considerable number of H + ions at this pH, exterior protonation of biosorbent results in the creation of a positively charged adsorbent.…”