Synthesis of zeolitic imidazolate framework‐8 modified graphene oxide composite and its application for lead removal

Abstract

Abstract BACKGROUND The removal of lead ions (Pb2+) from industrial wastewater can be achieved using adsorption technology. Composites of zeolitic imidazolate framework‐8 (ZIF‐8) and graphene oxide (GO) were prepared via room temperature synthesis (RTS) using RO water as the solvent and by mixing GO with separated parts of ZIF‐8 precursors before its combination. Three weight percentages of GO, 10wt%, 30wt% and 50wt%, were used to synthesize ZGH10, ZGH30 and ZGH50 to determine optimum preparation and application conditions. Results ZGH30 showed the most outstanding performance as an adsorbent for Pb 2+ removal from aqueous solution. As captured by field emission scanning electron microscopy image, ZGH30 showed an adequate amount of ZIF‐8 grown on all surfaces of thr GO sheet, with an appropriate exposure of GO sheet layers for further Pb 2+ interaction. The Pb 2+ adsorption test revealed that ZGH30 obtained the optimum operating values between pH 5 and 6, using 10 mg dosage and it could remove ≤97% of 100 mg L −1 Pb 2+ . Additionally, ZGH30 achieved the most rapid equilibrium time within 10 min, similar to ZGH50, as compared to their individual components, ZIF‐8 (240 min) and GO (300 min). The mechanism of Pb 2+ adsorption fitted well with a Langmuir isotherm and pseudo‐second‐order kinetic model. The theoretical maximum adsorption capacities obtained through Langmuir isotherm were 200, 454.55, 476.19, 555.56 and 454.55 mg g −1 , for GO, ZH, ZGH10, ZGH30 and ZGH50, respectively. Conclusions Therefore, ZGH30 hybrid successfully unleashed its potential as the adsorbent for wastewater treatment technology with improved performance after modification. © 2023 Society of Chemical Industry (SCI).