Preparation of bimetallic Pb/Zn metal-organic framework @graphene oxide composite and its adsorption performance for Pb(II) and Zn(II)
Zhuannian Liu, Mohammad Fahim Bakhtari, Xiaogang Han
Abstract
The removal of harmful heavy metals from water bodies has emerged as a major concern owing to ecological challenges and the associated threats and dangers they pose. In this study, we used graphene oxide (GO) as an adsorbent to absorb Zn2+ and Pb2+ in simulated wastewater. The Pb2+and Zn2+adsorbed on the surface of GO were utilized as metal ion centers, and benzene-1, 4-dicarboxylic acid (BDC) served as an organic linker to synthesize a bimetallic Pb/Zn-MOF@GO composite via the hydrothermal method. Pb/Zn-MOF@GO composite was characterized using SEM, XRD, FTIR and BET analytical methods. The Pb/Zn-MOF@GO shows a higher BET surface area of 460 m2 g-1 compared to that of Pb-MOF@GO (296 m2 g-1) and Zn-MOF@GO (408 m2 g-1). The maximum adsorption capacities of Pb/Zn-MOF@GO composite material for Zn2+ and Pb2+ were 114.68 and 132.62 mg L-1, respectively. The adsorption kinetics of the composite materials for Zn2+ and Pb2+ follow the pseudo-second order kinetic model, and the adsorption isotherm best fits the Langmuir model. The adsorption mechanism was governed by hydrogen bonding, and the -C=O reaction was also involved in the adsorption process. The findings of this study provide new insights into water pollution and resource utilization.