Adsorption of Cd2+ on GO/PAA hydrogel and preliminary recycle to GO/PAA-CdS as efficient photocatalyst

In this work, a GO (graphene oxide)/PAA (poly acrylic acid) hydrogel was prepared by graft polymerization between GO and AA. It was employed as highly efficient adsorbent for Cd2+ removal from wastewater. The GO/PAA-Cd2+ composite after the adsorption process was recycled through in-situ precipitation to obtain GO/PAA-Cd2+ composites. During the synthesis process, the amounts of GO and M were optimized to enable the hydrogel with maximum adsorption of Cd2+ (316.4 mg/g at 25 degrees C). The structure and chemical composites of GO/PAA hydrogel were investigated through FTIR spectra, Raman spectra, and TGA. The adsorption kinetics and isotherms of Cd2+ on GO/PAA were analyzed. The synthesized products served as an efficient adsorbent for Cd2+ and a suitable matrix for the CdS quantum dots formation which was confirmed by various characterizations, including XPS, SEM-EDS and HRTEM. The roles of GO and PM in the successive adsorption-photocatalyst process were proved to be complementary: PAA improved the adsorption of Cd2+ while GO enhanced the photocatalyst efficiency. The photodegradation rate of MB (30 mg/L) was over 90% within 2 h. (C) 2019 Elsevier B.V. All rights reserved.