Fabrication of recyclable magnetic carbon material adsorbent from waste ion exchange resin

Abstract

Recently, the circular economy aiming at recycle of waste as the raw material of new valuable products has attracted great interest. In this study the carbon material (CM) was obtained by carbonization of waste ion exchange resin (WIER) and the magnetic carbon material (MCM) was prepared by mixing CM with an aqueous Fe3+/Fe2+ solution followed by the NaOH treatment. Surface structure and charges of CM and MCM were characterized by SEM, XRD, FTIR and potentiometric titration. The surface charge analysis showed that surfaces of CM and MCM were negatively charged in the alkaline condition. The characteristic peaks of magnetite on MCM can be found in XRD patterns and FT-IR spectra. Adsorption capabilities of CM and MCM was tested in the methylene blue (MB) aqueous solution. MCM adsorption efficiency is 97.7 %, while 81.1 % of CM. MCM adsorption capacity is 13.9 mg/g, better than 10.33 mg/g of CM. Nearly 96 % MB was degraded in the Fenton-Like process by MCM. MCM reusability was verified in the adsorption/ desorption test conducted for five cycles, in which the adsorption efficiency remained 83.6 % at the fifth cycle. The experimental data were fitted by adsorption isotherms, showing that MB adsorption on CM and MCM were more consistent with Langmuir model. In the adsorption kinetic analysis, the pseudo-first order model fitted better for CM sorption, while the pseudo-second order model for MCM. This work revealed that WIER is a proper precursor of carbon adsorbent for MB dye, which would specifically reduce the environmental cost of waste disposal.