Efficient detection and adsorption of cadmium(II) ions using innovative nano-composite materials

Abstract

In this study, a ligand was anchored with mesoporous silica, named as nano-composite materials, was applied in the detection and adsorption of cadmium (Cd(II)) ions from wastewater samples. The effects of solution pH, color optimization, limit of detection, contact time, initial concentration, ion selectivity and regeneration were systematically performed in the case of detection and adsorption operations. The solution pH was played an important factor both in the case of detection and adsorption, and the optimum pH were selected at 5.50 based on the high absorbance and adsorption ability. Upon addition of Cd(II) ions, the nano-composite materials was provided an excellent color, which was observed by the naked-eye. The detection limit was calculated to be 0.33 µg/L, which was lower than the permissible limit. Therefore, the Cd(II) ions was detected without using any sophisticated instruments. The equilibrium isotherm has been analyzed using Langmuir isotherm models, and the maximum adsorption capacity was 148.32 mg/g. The results clarified that the nano-composite material had the higher selectivity towards Cd(II) ions even in the presence of high concentration of divers metal ions. The material was reused in several cycles after elution operation with a suitable eluent of 0.25 M HCl. The nano-composite materials exhibited an excellent reusability because of its remarkable mechanical strength and highly efficient elution/regeneration operations ability. In the static treatment process, after seven cycles, Cd(II) ions was adsorbed efficiently and holding over 93% adsorption efficiency. The developed ligand functionalized nano-composite materials is quite simple and rapid with excellent repeatability for Cd(II) ions capturing and has a great potential for potential scale up for field application in real wastewater samples.