Recyclable functionalized polymer films for the efficient removal of hexavalent chromium from aqueous solutions

Abstract

A PEI-PVA functionalized composite film has been developed to remove hexavalent chromium ion Cr(vi) from water by an adsorption–reduction mechanism.

Photoactive Polyethylenimine-Coated Graphene Oxide Composites for Enhanced Cr(VI) Reduction and Recovery

“…All adsorption capacities for Cr(VI) on amine group-functionalized materials are summarized in Table S2. 15,16,[19][20][21][22][23][24][25][26][27][28][29][30][31]64 We do note the rapid sorption kinetics of these observed processes compared to other literature reports. In the presence of UVA irradiation, Cr(VI) was photoreduced by PEI for all cases in a similar fashion to PEI alone (Figure S7), as discussed above.…”

“…The maximum sorption density also increased with decreasing solution pH: 217.4, 142.9, 52.1, and 12.2 mg/g for pH 3, 5, 7, and 9, respectively. All adsorption capacities for Cr­(VI) on amine group-functionalized materials are summarized in Table S2. ,,− , We do note the rapid sorption kinetics of these observed processes compared to other literature reports. In the presence of UVA irradiation, Cr­(VI) was photoreduced by PEI for all cases in a similar fashion to PEI alone (Figure S7), as discussed above.…”

“…Chromium treatment has traditionally been accomplished via separation from the dissolved phase through adsorption via anion exchange, precipitation, and coprecipitation reactions and through size exclusion processes (e.g., ultrafiltration). , To increase sorption and removal of Cr­(VI), in particular, net positively charged organic ligands have been applied through the surface modification of fungal biomass, aerobic granules, magnetic nanoparticles, , sludge, biochar, , and polymer films, among others. , A number of these rely on cationic organic molecules and polymers containing amine-based functional groups, which act as active binding sites, including polyethylenimine (PEI), polyaniline, ethylenediamine, chitosan, and so forth. − With respect to amine functionalization for the Cr­(VI) sorption and removal, a number of materials have been proposed and demonstrated. − Some of these reports also observe reduction of Cr­(VI) to Cr­(III), albeit relatively slow and under uncontrolled conditions with regard to light exposure. ,,,,, Interestingly, under UV irradiation, amine groups, in some cases, can be photochemically converted to amine radical cations, which can subsequently react . Such photoactivated amine radical cations have been used in various chemical redox (reduction-based) processes, , including the synthesis of gold nanoparticles, , production of hydrogen peroxide, electrochemistry, , and as part of overall synthesis pathway(s) for amine-functionalized organics. , Furthermore, while amine photochemistry has been explored, to a limited degree, for CO 2 reduction and water splitting, , there has been very little reported with regard to transformation of aqueous-based inorganic pollutants, in...…”

“…6 Chromium treatment has traditionally been accomplished via separation from the dissolved phase through adsorption via anion exchange, precipitation, and coprecipitation reactions and through size exclusion processes (e.g., ultrafiltration). 7,8 To increase sorption and removal of Cr(VI), in particular, net positively charged organic ligands have been applied through the surface modification of fungal biomass, 9 aerobic granules, 10 magnetic nanoparticles, 11,12 sludge, 13 biochar, 14,15 and polymer films, 16 among others. 17,18 A number of these rely on cationic organic molecules and polymers containing amine-based functional groups, which act as active binding sites, including polyethylenimine (PEI), polyaniline, ethylenediamine, chitosan, and so forth.…”