Cr(III) Ion-Imprinted Hydrogel Membrane for Chromium Speciation Analysis in Water Samples

Abstract

Novel Cr(III)-imprinted poly(vinyl alcohol)/sodium alginate/AuNPs hydrogel membranes (Cr(III)-IIMs) were obtained and characterized and further applied as a sorbent for chromium speciation in waters. Cr(III)-IIMs were prepared via solution blending method using blends of poly(vinyl alcohol) and sodium alginate as film-forming materials, poly(ethylene glycol) as a porogen agent, sodium alginate stabilized gold nanoparticles (SA-AuNPs) as a crosslinking and mechanically stabilizing component, and Cr(III) ions as a template species. The physicochemical characteristics of pre-synthesized AuNPs and obtained hydrogel membranes Cr(III)-IIM were studied by UV-vis and FTIR spectroscopy, TEM and SEM observations, N2 adsorption–desorption measurements, and XRD analysis. The mechanism of the adsorption process toward Cr(III) was best described by pseudo-first-order kinetic and Langmuir models. Experiments performed showed that quantitative retention of Cr(III) is attained in 20 h at pH 6 and temperature 40 °C. Under the same conditions, the adsorption of Cr(VI) is below 5%. A simple and sensitive analytical procedure was developed for the speciation of Cr in an aquatic environment using dispersive solid phase extraction of Cr(III) by Cr(III)-IIM prior to selective Cr(VI) measurement by ETAAS in the supernatants. The detection limits and reproducibility achieved for the Cr speciation analysis fulfill the requirements for their monitoring in waters under the demand of the Water Framework Directive.

Efficient Removal of Heavy Metals from Aqueous Solution Using Licorice Residue-Based Hydrogel Adsorbent

“…Hence, non-linear models are not suitable for accurately depicting the adsorption behavior of Cr 3+ . Additionally, the homogenous distribution of surface groups on the prepared hydrogels, as observed through FTIR and SEM analyses, supports the conclusion that the adsorption of Cr 3+ is still monolayer adsorption, which is consistent with the findings of other studies [60,61].…”

Ion-Imprinted Polymeric Materials for Selective Adsorption of Heavy Metal Ions from Aqueous Solution

“…Separation and preconcentration of Cr(III) from water by Cr(III)-IIP sorbents based on ion-imprinted-functionalized mesoporous SiO 2 have been lately explored ( Table S7 ) [ 137 , 138 , 139 , 140 , 141 , 142 ]. Liu et al, have developed a Cr(III)-IIP by one-step sol–gel reaction using APTEOS as a coupling agent and a Cr(III) surface imprinting on the surface of a mesoporous SiO 2 (SBA-15) [ 137 ].…”

“…In competition with Ni(II), Co(II), Al(III), Eu(III), Cu(II), and Fe(III), in binary systems, the relative selectivity for Cr(III) increased in the order: 9.37, 9.38, 9.85, 10.98, 13.26, and 15.15, respectively. Cr(III)-ion imprinted membranes (Cr(III)-IIMs) were prepared from ALG and PVA as film-forming polymers, poly(ethylene glycol) (PEG) as porogen, and ALG coated gold nanoparticles (ALG-AuNPs) as the cross-linker and Cr(III) ions as the template [ 142 ]. Under the optimum conditions of sorption, the adsorption of Cr(VI) was <5%, thus allowing the selective measurement of Cr(VI) after the adsorption of Cr(III).…”

Self-Assembling Peptide-Based Magnetogels for the Removal of Heavy Metals from Water

“…Kinetic behavior was studied using non-linear pseudo-first order and pseudo-second order kinetic models (Equations ( 9) and ( 10)) [108,110]. log(q e − q t ) = logq e − k 1 t/2.303 (9) t/q t = 1/k 2 q e 2 + t/q e (10)…”

“…The presence of toxic metal ions in industrial wastewaters can result in adverse effects on both human health and the environment even at low concentrations because these inorganic species are generally nondegradable in nature [1][2][3]. Some of the most In the past decades, there have been admirable efforts to develop fast and efficient techniques to remove metal ions from aqueous solutions, and different approaches have been studied and developed for water remediation, including ion exchange, electrochemical treatments, membrane separation, and flocculation [1,9]. However, these methods often suffer from their own limitations in terms of complexity, cost, and efficiency.…”