Characterization of Acidified Opal Shale and Dynamic Adsorption of Toluene

Abstract

Different kinds of acidified opal shale powders were obtained through the activation of natural opal shale powders with different concentrations of sulfuric acid. The natural opal shale and different acidified opal shale materials were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. It was found that the opal shale has good acid resistance stability. When the sulfuric acid concentration reaches a high concentration of 6 mol/L in the acidification treatment, the opal shale can still maintain its original main silica structure. Natural opal shale is a typical mesoporous material with a BET specific surface area of about 12 nm, but it also contains a small amount of micropores and macropores. Appropriate acid treatment can increase the specific surface area. An excessively high concentration of acid that exceeds 6 mol/L sulfuric acid can destroy the main structure of the cation, resulting in a decrease in the specific surface area. In this paper, the adsorptive breakthrough curves for toluene, dynamic saturated adsorption capacity and other gas adsorption performances of these materials were studied. Finally, the best adsorption material was the 2 mol/L sulfuric acid acidified opal shale at 333K under stirring for 4 hours.