Reduction-adsorption of chromium(VI) by using IL-imprinted resin -innovative solution for water purification

Abstract

Novel sorbents (poly(vinylbenzyl chloride-co-divinylbenzene) functionalized with Ionic Liquids precursors- hydrophobic and hydrophilic 3- and 4-pyridineketone and oxime were prepared for application to chromium removal. The fabricated materials were extensively characterized (surface morphology, FT-IR, NMR, Raman, microscopy, XPS, and wettability). The efficiency of functionalization of poly(vinylbenzyl chloride-co-divinylbenzene was demonstrated not only in the process of adsorption of chromium(VI), but also in its reduction to a less toxic form of trivalent ions. I was shown that the efficiencies of both processes depended on the time, pH of the aqueous phase and the initial concentration of Cr(VI). At pH of 0 the cumulative chromium removal was preferable (removal almost 1200 mg of Cr) with the reduction as the dominant process. At pH of 3.5 and higher only adsorption was observed with the maximum capacity of 144.4 mg/g. The conducted analytical techniques, such as Raman and XPS, enabled to determine the mechanism of the sorption and the surface Cr(VI) reduction that oxidize water to O2. The studies indicated that this research direction was forward-looking and fits in with the trends of a sustainable development- simultaneous reduction and adsorption of chromium from wastewater.