Synergistic Interactions between Activated Carbon Fabrics and Toxic Hexavalent Chromium

Abstract

The synergistic interactions between the activated carbon fabrics (ACFs) and the toxic Cr(VI) were investigated aiming to functionalize the ACFs and to remove the toxic Cr(VI). The effects of pH, treatment time, initial Cr(VI) concentration and ACFs dose on the Cr(VI) removal were studied. Different pH values had different effects on the Cr(VI) removal by ACFs, pH = 1.0 was found to be the optimum. For the pH = 1.0 solution, the Cr(VI) in the aqueous solution was reduced to Cr(III) and adsorbed onto the ACFs, and the C-O and C=O functional groups were found on the ACFs surface. The redox kinetic in the pH = 1.0 solution could be described by the pseudo-first-order model and the typical value of the pseudo-first-order rate constant was calculated to be 0.0872 min −1 . Langmuir, Freundlich, and Temkin adsorption isotherm models were applied to describe isotherm behaviors. The Cr(VI) equilibrium data agreed well with the Langmiur isotherm model with a maximum adsorption capacity of 5.59 mg g −1 . The ACFs could be easily regenerated by 1.0 mol L −1 sodium hydroxide and effectively recycled 7 times with the removal percentage decreased by 16.5%, which was caused by the irreversible formation of oxygen functional groups on the surface of ACFs.

Effect of acid modification on adsorption of hexavalent chromium (Cr(VI)) from aqueous solution by activated carbon and carbon nanotubes

“…However, for raw and modified CNTs, the maximum adsorption occurs at pH 4 and 3, respectively. [15,28]. Dichromate ions (Cr 2 O 2À 7 ) are the dominant species at lower pH, while at higher pH, only chromate (CrO 2À 4 ) ion exists in the solution.…”

“…Chromium concentration in industrial water varies from 5.2 to 208,000 mg/L [9,10]. The World Health Organization (WHO) designated a guideline value of 50 μ/L for chromium in drinking water [11][12][13], while the allowable limit for Cr(VI) in water as suggested by the US Environmental Protection Agency is 0.1 mg/L [12][13][14][15].…”

Polyethylenimine Facilitated Ethyl Cellulose for Hexavalent Chromium Removal with a Wide pH Range

“…2,3 Among the reported technologies, including the electrochemical precipitation, 4 ion exchange, 5 membrane separation, 6 photocatalysis, 7,8 and adsorption 3,9 to remove Cr(VI), adsorption is widely used due to its easy operation and great removal performance. 10−12 Adsorbents such as iron, 13 zero-valence aluminum (ZVAl), 2 polymers, 10,14,15 and biomass 16,17 have demonstrated high efficiency in removing Cr(VI).…”

Hexavalent chromium removal in contaminated water using reticulated chitosan micro/nanoparticles from seafood processing wastes

“…In the last years very interesting works have been published concerning the removal of hexavalent chromium using adsorbent materials that can reduce Cr(VI) to the less or nontoxic Cr(III) and simultaneously adsorb the reduced Cr(III) (Bellú et al, 2010;Gu et al, 2012;Huang et al, 2013;Park et al, 2008;Qiu et al, 2014aQiu et al, ,b,c,d, 2015Sankararamakrishnan et al, 2006;Sivakami et al, 2013;Xu et al, 2014;Zhang et al, 2010Zhang et al, , 2013Zhu et al, 2012Zhu et al, , 2014. These adsorbents not only act as electron donors for the Cr(VI) reduction, but also have active sites for Cr(III) adsorption.…”

“…These adsorbents not only act as electron donors for the Cr(VI) reduction, but also have active sites for Cr(III) adsorption. Different materials were analyzed and techniques such as X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS) were applied to determine the oxidation state of the adsorbed chromium species (Bellú et al, 2010;Park et al, 2008;Qiu et al, 2014aQiu et al, ,b, 2015Xu et al, 2014).…”