Effective Cr(VI) Removal from Simulated Groundwater through the Hydrotalcite-Derived Adsorbent

Abstract

We investigated the feasibility of using calcined hydrotalcite (CHT) as the adsorbent of chromate to treat Cr(VI)-contaminated water through column tests under varied conditions. The column tests reveal that CHT can take up 34.3−44.7 mg(Cr)/g when the Cr(VI) concentration in the influent varies over a range of 50−200 mg/L (e.g., 0.96−3.85 mM) with pH 6−7 at 298 K. This uptake capacity is only reduced to 29.1 mg(Cr)/g when HCO3 − (1.0 mM) and Cl− (1.0 mM) coexist in the influent. We note that the treated water is of high quality and is free of Cr(VI), with Mg and Al concentrations of <5−10 mg/L, and a pH of 6.5−7.0. The quick desorption of Cr(VI) from the adsorbent (CHT) has enabled us to recover Cr(VI) from the contaminated water and regenerate the adsorbent. All these findings promise CHT as an effective regenerable adsorbent for the remediation of Cr(VI)-contaminated groundwater.

Reduction and removal of Cr(VI) from aqueous solutions using modified byproducts of beer production

“…Several treatment methods for Cr(VI) removal from industry wastewater have been established, i.e., electrochemical precipitation, ion exchange, membrane ultrafiltration, reverse osmosis, reduction, and adsorption [1][2][3][4][5]. However, most of these methods are costly due to operational, treatment and sludge disposal costs.…”

Simultaneous Adsorption of Chromium (VI) and Phosphate by Calcined Mg-Al-CO3Layered Double Hydroxides

“…2) corresponded to the characteristic vibration of Cr (VI). 30 The FTIR spectra did not show such a strong absorbance intensity of Cr (VI), when P and Cr (VI) were simultaneously absorbed by CLDH, which demonstrated that the presence of P decreased the adsorption of Cr (VI) and competitive adsorption between P and Cr (VI) occurred.…”

“…29 Furthermore, the broad peaks were attributed to the formation of Mg-Al mixed oxides. In the current column test, it is assumed that CLDH can adsorb ions via three mechanisms: (i) electrostatic attraction on surface, (ii) ion exchange interaction between anions and hydroxyl ions, (iii) regeneration of its initial layered structure, as expressed by the following reaction: 29,30 (1)…”

Enhanced remediation of Cr(VI)-contaminated soil by incorporating a calcined-hydrotalcite-based permeable reactive barrier with electrokinetics

“…Particularly, a family of anionic clay materials, hydrotalcite-like materials (HTs) have shown a high adsorption capability for various anions [10][11][12][13], such as chromate (Cr(VI)), exhibiting the potentiality as PRB reactive media to remove this soil contaminant. HTs are exemplified by the naturally existing hydrotalcite (Mg 6 Al 2 (OH) 16 [14]. Its most important property is the high anion exchange capacity.…”