Synthesis and characterization of NH2-SiO2@Cu-MOF as a high-performance adsorbent for Pb ion removal from water environment

Abstract

Heavy metal pollution is becoming a global health and environmental concern, so preventing damage to nature is of high significance. In this work, NH2-SiO2 NPs’ immobilization on Cu-MOF was performed to fabricate an effective adsorbent for Pb(II) elimination from aqueous environments. Prepared adsorbent benefits from the combination of functional groups of NH2-SiO2 NPs and porous crystalline structure of Cu-MOF. The results revealed that the adsorption of Pb metal ions onto NH2-SiO2@Cu-MOF follows a Langmuir isotherm and the maximum adsorption capacity was found to be 166.67 mg/g. The kinetic studies showed that the data of Pb adsorption on NH2-SiO2@Cu-MOF are in good agreement with the pseudo-second-order model and the potential mechanism for the adsorption process confirmed as the coordination interaction between N in the amino group (–NH2) and Pb(II). The experimental factors which had the most impact on the adsorption were investigated. The highest performance of the adsorbent appeared at a pH value of 6. The NH2-SiO2@Cu-MOF showed excellent performance in real samples and capability for reuse of up to 5 cycles. Briefly, results indicate that the NH2-SiO2@Cu-MOF is a promising alternative for selective removal of Pb(II) from the aqueous environment.