Modified mesoporous zeolite-A/reduced graphene oxide nanocomposite for dual removal of methylene blue and Pb2+ ions from wastewater

Abstract

In this work, 3-aminopropyl- trimethoxysilane (APTMS) used as a mesopore generating and cross linkage agent in the preparation of modified mesoporous zeolite-A /reduced graphene oxide nanocomposite (MZ-A/RGO) using hydrothermal method for the high-performance dual removal of methylene blue (MB) and lead ions (Pb2+), which are toxic pollutants of wastewater. Different characterization techniques were used to characterize the MZ-A/RGO. Parameters that included the contact time, initial adsorbate concentrations, pH, sorbent dosages, temperature and ionic strength were varied to investigate the removal efficiency of MB and Pb2+ ions by MZ-A/RGO. The reusability of MZ-A/RGO sorbent was studied for removal of MB and Pb2+ ions in five cycles adsorption/desorption process. The sorption kinetics data were fitted using pseudo-first-order, pseudo-second-order and Elovich kinetic models. In addition, four different adsorption isotherm models – the Freundlich, Langmuir, Temkin and Dubinin–Radushkevich (D-R) – were applied to study the adsorption mechanism. The results indicate that the maximum removal efficiency was achieved during the first 20 min for both MB and Pb2+ ions and equal to 98.5% for MB and 93.9% for Pb2+ ions, respectively. The adsorption process followed pseudo-second-order kinetics. Furthermore, the Langmuir model provided the best fit of the MB and Pb2+ ions adsorption isotherms, with correlation coefficients equal to 0.996 and 0.995, respectively. The reusability experiment exhibits good adsorption result, that indicate the economic and efficient adsorbent in wastewater treatment. In addition, the results indicate that the dual removal efficiency of MZ-A/RGO for MB and Pb2+ ions from wastewater.