Different decorated ZIF-67 adsorption performance towards methamphetamine revealed by theoretical and experimental investigations

Abstract

Metal-organic framework (MOF) materials, which have been deemed as effective adsorbents for removing emerging contaminants, suffered from difficult separation that limited their application in water treatment. Two different decorated ZIF-67 multifunctional adsorbents have been successfully fabricated by anchoring ZIF-67 on diverse magnetic substrates. The comparative study combining a series of adsorption experiments and structural characterization analyses was facilitated to explore the adsorption performance of two adsorbents (MrGO/ZIF and MZIF). The better adsorption capacity of MrGO/ZIF for methamphetamine (MAMP) was observed. For the introduction of reduced graphene oxide (rGO), ZIF-67 nanocrystals showed stratified multidimensional distribution on rGO, and formed a stepped pore structure. Relatively large pores of MrGO/ZIF were beneficial for the transport and adsorption of MAMP in aqueous phase. The adsorption of MAMP could be described by the Langmuir isotherm and pseudo-second-order kinetic model, and adsorption process was spontaneous and endothermic. Theoretical investigation in combination with analyses of the XPS characterization illustrated that the H-bonding interaction between the Co−OH and −NH of MAMP, and π-π interaction among the heteroaromatic rings in adsorbent and the benzene ring of MAMP was the mainly contribution of driving MAMP adsorption on MrGO/ZIF. Summarily, the excellent adsorption properties of MrGO/ZIF coupled with facile separation and sustainability make MrGO/ZIF remove MAMP more efficiently from water, which provide an insight for contaminated water treatment, and psychoactive substances monitoring.