Adsorption of cationic dye from aqueous solution using SBA-15 nano particles synthesized by stem sweep ash as the source of silica

Abstract

Today, many efforts have been made to use agricultural waste as a cheap and abundant resource for providing suitable adsorbents to remove pollutants such as industrial dyes. The aim of this study was to remove dye from water under different conditions using SBA-15 nano particles as adsorbents their silica was prepared from stem sweep ash (SSA). Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and N2 adsorption experiments were applied to evaluate the structural characteristics of obtained adsorbent. In addition, to remove Azure B dye by SBA-15, the optimal values were obtained as the parameters of contact time = 30 min, pH = 8, temperature = 65 °C, adsorbent amount = 0.01 g, stirring rate = 90 rpm and initial dye concentration = 100 mg/L. The kinetic and thermodynamic experiments were conducted on the adsorption process as well. The results of the experiments demonstrated that the total surface area and total pore volume of the adsorbent were 780 m2/g and 0.8483 cm3/g, respectively. Moreover, the surface adsorption process of Azure B followed the Langmuir's isothermal model, and kinetic data followed the surface adsorption of pseudo-second-order kinetic model. Besides, the values of ΔH° and ΔS° were 5409.32 j/mol and 37.28 j/mol K, respectively, and the maximum adsorption capacity of adsorbent was 166.66 mg/g.