Cadmium cation uptake through amine and acid post-functionalized Santa Barbara Amorphous materials; comprehensive adsorption studies

摘要

In this research, a novel adsorbent, nitrilotriacetic acid anhydride (NTAA) and 3-aminopropyltriethoxysilane (APTES) modified Santa Barbara Amorphous materials (SBA-15) as a mesoporous silica was synthesized and applied for the adsorption of cadmium solution. X-ray diffraction, transmission electron microscopy, scanning electron microscopy, nitrogen adsorption-desorption isotherms and Fourier transform infrared analysis were used. The adsorption experiments were performed during batch system containing different concentrations of cadmium solution (60-120 mg/L) in pH range of 2-10, adsorbent dosage of 100-600 mg/L with contact time interval of 15-120 min. The maximum cadmium removal was achieved at pH 6 with 250 mg/L of adsorbent after 60 min. The proposed mechanisms for the removal and capture of Cd~(+2) ions by adsorbent are electrostatic interactions and chelation. The equilibrium studies prove that the experimental data are compatible with the Langmuir isotherm model well with the maximum adsorption capacity of 500 mg/g. Kinetic and thermodynamic studies also indicate that pseudo-second order kinetic model is the predominant model and the adsorption process is exothermic. This study reveals a high capability of novel nano-adsorbent for the efficient removal of hazardous heavy metal cations and anions from wastewater.