Sulfated Zirconia Synthesized in a One Step Solvent-Free Method for Removal of Olefins from Aromatics

Abstract

Sulfated zirconia was synthesized by a one step solvent-free method, directly mixing Zr(OH)4 and (NH4)2SO4. The entire synthesis process produces no wastewater, which is environmentally friendly. The synthesis factor (mole ratio of (NH4)2SO4:Zr(OH)4) is the main point to test catalytic activity. Structural properties are characterized by X-ray diffraction (XRD), N2 adsorption–desorption isotherms, and inductively coupled plasma (ICP). The acid property is characterized by pyridine-FTIR. The S coverage (×10–6 mol S·m–2)–Lewis acidic sites density (mmol·m–2) relationship in sulfated zirconia reveals that the generation order of Lewis acidic sites is from weak ones to strong ones. Calculation of acid property reveals the positive structural–functional relationship (WL/SL–catalytic activity). Weak Lewis acidic sites (WL) promote the activity toward removal olefins, while strong Lewis acidic sites (SL) speed up the deactivation of catalysts. The superior catalytic performance as well as environmentally friendl...