Preparation, characterization, and desulfurization ability of bulk porous silica-supported ZnO

Abstract

The facile preparation of bulk porous silica and a desulfurization ability of this silica-supported ZnO as application are reported. Bulk porous silica was prepared by the sol–gel method using tetraethoxysilane (TEOS) and surfactant as a template. The swollen gel was filled in a plastic vial followed by curing for 1 day. Bulk porous silica was prepared by the calcination of the cured gel. The bulk porous silica was characterized by nitrogen adsorption–desorption measurements and transmission electron microscopy (TEM). The bulk porous silica has micropore and mesopore: the micropore distribution was calculated to be 1.7 nm by the MP method and the mesopore-size distribution was calculated as 6.3 nm by the Barrett–Joyner–Halenda method. The volume of micropore was larger than that of mesopore; hence, bulk porous silica would be formed as a pillared-clay-like structure. Bulk porous silica-supported ZnO was prepared by the impregnation of ZnCl2 followed by calcination in air. The content of ZnO in bulk porous silica (1.9, 15.3, 33.8, and 46.2 wt%) was determined by inductively coupled plasma atomic emission spectrometry, and the ZnO content was depended on the concentration of ZnCl2 aqueous solution. Characterization was achieved by nitrogen adsorption–desorption measurements and TEM. The specific surface area decreased with increasing concentration of ZnO because ZnO deposited onto wall within pores. The sulfurization capacity of the bulk porous silica-supported ZnO was evaluated, and the sulfurization capacity per gram of the bulk porous silica-supported 46.2 wt% ZnO showed 12.56 mg/g.