Adsorptive Removal of Pyridine from Aqueous Solution Using Natural Shale

Abstract

The discharge of pyridine bearing wastewater into water bodies without a prior satisfactory treatment would pose significant public health risk as well as serious threat to the aquatic ecosystems. In this study, a natural shale from Yichang, China is investigated to determine its potential as a low-cost adsorbent for trace pyridine removal from wastewaters. The prepared shale samples without surface modification are characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscope (SEM). Kinetics and isotherms of pyridine from aqueous solutions onto shale are investigated on the basis of the experimental data. It is found that the shale samples with well-developed porosity are mainly composed of illite, quartz, calcite, chlorite and sericite. Several kinetic models (viz. pseudo-first-order, pseudo-second-order, two-constant rate, intra-particle diffusion and Elovich) as well as isotherm models (Langmuir, Freundlich and Temkin) are applied to test the experimental data for pyridine removal. The kinetics of the adsorption of pyridine by shale follows a pseudo-second-order rate law with the adsorption data being best described by the Freundlich isotherm model. The preliminary study shows that natural shale obtained from sedimentary basins may be used as a potential low-cost adsorbent for the removal of trace pyridine from effluents.