Efficient removal and environmentally benign detoxification of Cr(VI) in aqueous solutions by Zr(IV) cross-linking chitosan magnetic microspheres

Development, modification, and application of low-cost and available biochar derived from corn straw for the removal of vanadium(v) from aqueous solution and real contaminated groundwater

“…ZnCl 2 impregnation could signicantly increase the generation of mesopores and micropores, the specic surface area, and the yields of biochar. [23][24][25][26] Recently, transitional Zr(IV)-binding chitosan complexes, orange waste gel and AC have been applied for the removal of phosphate, 27,28 As(V) and As(III), 29,30 Cr(VI) and vanadium(V), 13,31,32 because hydrous Zr(IV) can form tetrahedral geometries with abundant water molecules and hydroxyl ions, which could give rise to adsorption sites and high adsorption affinity toward oxyanions. Moreover, Zr(IV) in its hydrated form can resist the adsorption of alkalis, acids, reductants and oxidants, which can improve the selectivity of the absorbents.…”

Perspectives regarding metal/mineral-incorporating materials for water purification: with special focus on Cr(vi) removal

“…Zirconium(IV) cross-linked chitosan magnetic microspheres (Fe 3 O 4 @Zr-chitosan) as a recoverable adsorbent were fabricated through the coordination reaction between zirconium oxychloride and a chitosan biopolymeric matrix for efficient adsorption and simultaneous detoxification of Cr(VI) in aqueous solutions. 202 XRD and SEM verified the formation of core@shell magnetite microspheres. XPS and FT-IR confirmed Zr(IV)'s cross-linking with chitosan on the microspheres.…”

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

“…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]. 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.…”

“…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]. Some of these techniques have disadvantages of either producing toxic sludge as is the case of chemical precipitation, or asking for high capital costs (reverse osmosis), recovery of value metal being difficult [27,28].…”

“…Therefore, the scientific and technological interest is lately focused on designing novel sorbents endowed with fast adsorption/desorption rate of Cr(VI) oxyanions, high mechanical strength, selectivity, and high reusability. These requirements could be successfully fulfilled by organic/inorganic composites [18,19,[31][32][33][34][35][36][37][38][39][40][41]. Thus, magnetic composite sorbents, which allow their easy magnetic separation from the aqueous environment, have been recently reported [31,33,34].…”