Effective removal and fixation of Cr(VI) from aqueous solution with Friedel's salt

Dai, Yingchun, Qian, Guangren, Cao, Yali, Chi, Ying, Xu, Yunfeng, Zhou, Jizhi, Liu, Qiang, Xu, Zhi Ping and Qiao, ShiZhang (2009) Effective removal and fixation of Cr(VI) from aqueous solution with Friedel's salt. Journal of Hazardous Materials, 170 2-3: 1086-1092. doi:10.1016/j.jhazmat.2009.05.070

Author Dai, Yingchun
Qian, Guangren
Cao, Yali
Chi, Ying
Xu, Yunfeng
Zhou, Jizhi
Liu, Qiang
Xu, Zhi Ping
Qiao, ShiZhang
Title Effective removal and fixation of Cr(VI) from aqueous solution with Friedel's salt
Journal name Journal of Hazardous Materials   Check publisher's open access policy
ISSN 0304-3894
Publication date 2009-10-30
Sub-type Article (original research)
DOI 10.1016/j.jhazmat.2009.05.070
Volume 170
Issue 2-3
Start page 1086
End page 1092
Total pages 7
Editor G Lyberatos
M F Fingas
Place of publication London, England
Publisher Elsevier
Collection year 2010
Language eng
Subject 09 Engineering
100708 Nanomaterials
970103 Expanding Knowledge in the Chemical Sciences
Abstract Friedel's salt (3CaO·Al2O3·CaCl2·10H2O or Ca4Al2(OH)12Cl2(H2O)4) is a calcium aluminate hydrate formed by hydrating cement or concrete in seawater at a low cost. In the current study, we carefully examined the adsorption behaviors of Friedel's salt for Cr(VI) from aqueous solution at different concentrations and various initial pHs. The adsorption kinetic data are well fitted with the pseudo-first-order Lageren equation at the initial Cr(VI) concentration from 0.10 to 8.00 mM. Both the experimental and modeled data indicate that Friedel's salt can adsorb a large amount of Cr(VI) (up to 1.4 mmol Cr(VI)/g) very quickly (t1/2 = 2–3 min) with a very high efficiency (>99% Cr(VI) removal at [Cr] < 4.00 mM with 4.00 g/L of adsorbent) in the pH range of 4–10. In particular, the competitive adsorption tests show that the Cr(VI) removal efficiency is only slightly affected by the co-existence of Cl− and HCO3−. The Cr(VI)-fixation stability tests show that only less than 0.2% adsorbed Cr(VI) is leaching out in water at pH 4–10 for 24 h because the adsorption/exchange of Cr(VI) with Friedel's salt leads to the formation of a new stable phase (3CaO·Al2O3·CaCrO4·10H2O). This research thus suggests that Friedel's salt is a potential cost-effective adsorbent for Cr(VI) removal in wastewater treatment.
Keyword Layered double hydroxides (LDHs)
Friedel's salt
Cr(VI) fixation
Chromate hydrocalumite
Layered Double Hydroxides
Hexavalent Chromium
Q-Index Code C1
Q-Index Status Confirmed Code

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Created: Thu, 12 Nov 2009, 12:02:12 EST by Mr Andrew Martlew on behalf of Aust Institute for Bioengineering & Nanotechnology