Synthesis of thiol-functionalized of hierarchical ZSM-۵ for removing heavy metals and kinetics study for this adsorption

In this work, hierarchical ZSM-۵ is prepared by alkaline treatment of ZSM-۵. Then terminal Si-OH and Al- OH generated at the hierarchical zeolites during desilication are functionalized with thioglycolic acid and was applied to remove heavy and toxic metal ions from wastewater. Optimal experimental conditions, including adsorbent concentration and contact time have been investigated. The maximum removal amount of functionalized mesoporous ZSM-۵ zeolite for Hg (II) and Pb (II) was found to be ۱۸۰۰ and ۱۹۹۶ mg/g, respectively. Adsorption kinetics were studied and fitted by different models. The adsorption kinetics are best described by pseudo first-order model. Desorption studies show that Pb۲+ and Hg۲+ can be desorbed from the catalyst surface using HNO۳. Thioglycolic -functionalized mesoporous ZSM-۵ zeolite were characterized by Fourier transform infrared (FT-IR) spectrometry, X-ray diffraction (XRD) and scanning electron microscopy (SEM).

Keywords:

Nano-adsorbent , ZSM-۵ zeolite , Heavy metal , thiol-functionalized