Recent advances in hexavalent chromium removal from aqueous solutions by adsorptive methods

Abstract

Despite the extensive existence of adsorbents for Cr(vi) removal from aqueous solutions, new adsorbents and modification of existing adsorbing materials are continuously sought after.

Preparation of cationic surfactant-modified kaolin for enhanced adsorption of hexavalent chromium from aqueous solution

“…Toxic effluents discharged without being treated from various industries have taken huge responsibility for the pollution of water bodies. Among the toxic pollutants, chromium is the subject of many types of research and has taken huge attention in the last few years (Yusuff 2019; Pakade et al 2019). Chromium can be found in stable Cr(VI) or Cr(III) oxidation states.…”

Contribution of Cross-Linker and Silica Morphology on Cr(VI) Sorption Performances of Organic Anion Exchangers Embedded into Silica Pores

“…Nowadays, finding highly efficient systems for the removal of heavy metal ions (HMIs) from the aquatic environment is a stringent issue in front of the scientists all over the world, because they are highly toxic (even at low concentrations), not biodegradable, and have an accumulation tendency in living organisms-most of them being carcinogenic. Synthetic polymeric sorbents [1][2][3][4][5][6] and various biosorbents [7][8][9][10][11][12] are investigated for their performances in the recovery/removal of HMIs. Among the HMIs present in the wastewaters, chromium, especially Cr(VI), is one of the most dangerous contaminants of the surface and ground water, being considered a powerful carcinogenic and teratogenic agent threatening living organisms [1,2,11,[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29].…”

“…Among the HMIs present in the wastewaters, chromium, especially Cr(VI), is one of the most dangerous contaminants of the surface and ground water, being considered a powerful carcinogenic and teratogenic agent threatening living organisms [1,2,11,[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. On the other hand, Chromium(III) is listed as an essential element, as a micronutrient, being involved to maintain the normal metabolism of glucose, cholesterol, and fat in human bodies [1,2], being poisonous only at a high concentration.…”

“…Cr(VI) is highly mobile in the environment, can easily penetrate the cell membrane having a corrosive effect on tissues, including lung cancer, and kidney, liver, and stomach [17]. According to the World Health Organization (WHO) drinking water guidelines, the maximum allowable limit for total chromium is 50 µg/L [1,2]. Therefore, to avoid the dangerous impact of Cr(VI) on human health and on the environment, as well as for economic considerations, it is essential to remove/recover Cr(VI) from the wastewaters before disposal [1][2][3].…”

“…According to the World Health Organization (WHO) drinking water guidelines, the maximum allowable limit for total chromium is 50 µg/L [1,2]. Therefore, to avoid the dangerous impact of Cr(VI) on human health and on the environment, as well as for economic considerations, it is essential to remove/recover Cr(VI) from the wastewaters before disposal [1][2][3]. Various techniques are available for the removal of Cr(VI) such as ion exchange, chemical precipitation, reduction [13,14], reverse osmosis, foam flotation, electrolysis, membrane filtration [15,16], ultrafiltration [17], sorption, and biosorption [18][19][20][21][22][23][24][25][26][27][28][29][30][31].…”