The reduction of Cr(VI) to Cr(III) mediated by environmentally relevant carboxylic acids: State-of-the-art and perspectives

Direct Z-scheme α-MnO2@MnIn2S4 hierarchical photocatalysts with atomically defined junctions for improved photocatalytic activities

“…Moreover, dealing with highly toxic hexavalent chromium is a difficult task in the treatment of world environmental pollution 13,14 . Based on trivalent chromium's low toxicity and easy flocculation into Cr(OH) 3 in an alkaline environment, reducing Cr (VI) to trivalent chromium has become a key procedure for environmental remediation 15,16 . Among the currently developed reduction methods, the photocatalytic reduction has shown potential application prospects compared with the high-cost chemical reduction method 17 and the biological reduction method 18 with high environmental requirements.…”

Removal of Chromium from a Contaminated Soil Using Oxalic Acid, Citric Acid, and Hydrochloric Acid: Dynamics, Mechanisms, and Concomitant Removal of Non-Targeted Metals

“…Previous studies have shown OX to have a significant role in both Cr(VI) reduction and Cr(III) complexation [14,44,45]. CA also can increase the reduction of Cr(VI) and the subsequent formation of soluble Cr(III)-citrate [45], and solubilize the Cr(III) by complexation and desorb the Cr(VI) by competition for surface sites [24].…”

“…Organic acids such as CA and OX are considered biodegradable and environment-friendly low molecular weight organic acids [10,12,13], which may exert less adverse influences on soil quality. Differently to HCl, organic acids CA and OX can act as reducers and chelates of toxic metals, such as Cr [14]. Inorganic and organic acids may have different removal mechanisms during Cr leaching, and concomitant effects on leaching of non-targeted elements.…”

Functionalized chitosan with butylammonium ionic liquids for removal of Cr(VI) from aqueous solution

“…Considering the above, it is important to study ways to uptake chromium from the environment. Hence, several mechanical, physical, chemical, and biological methods have been employed to treat effluents containing heavy metals 14–16 . These methods include flocculation, oxidation/reduction, hyperfiltration, photocatalytic degradation, ion exchange, co‐precipitation, biosorption, reverse osmosis, and adsorption 17–19 …”

“…Hence, several mechanical, physical, chemical, and biological methods have been employed to treat effluents containing heavy metals. [14][15][16] These methods include flocculation, oxidation/reduction, hyperfiltration, photocatalytic degradation, ion exchange, co-precipitation, biosorption, reverse osmosis, and adsorption. [17][18][19] The adsorption process is easily manageable, highly efficient, flexible, low-cost, and widely used in industrial effluent treatments.…”