Nano mesocellular foam silica (MCFs): An effective adsorbent for removing Ni2+ from aqueous solution

Abstract

Nano mesocellular foam silica (MCFs) was synthesized through the hydrothermal method in this study. Powder X-ray diffraction and scanning electron microscopy were used to characterize the MCFs sample. The sample presented spherical particles and regular morphology. The results of transmission electron microscopy showed that synthesized MCFs has a three-dimensional honeycomb pore structure, which aids in the adsorption of nickel ion (Ni2+). The results of low-temperature nitrogen gas adsorption-desorption showed that the pore diameter of the synthesized MCFs was 19.6 nm. The impacts of pH, temperature, amount of adsorbent, initial concentration of Ni2+, and contact time on the adsorption effect of Ni2+ by MCFs were studied. Under the optimized adsorption conditions, the adsorption rate reached 96.10% and the adsorption capacity was 7.69 mg/g. It has been determined through the study of kinetics and adsorption isotherms that the adsorption of Ni2+ by MCFs follows the pattern of the pseudo-second-order kinetic model, simultaneously belonging to the Freundlich adsorption type. The thermodynamic results of adsorption showed that, when the temperature is between 25°C and 45°C, the adsorption is a spontaneous exothermic reaction. Keywords: Nickel ion, Adsorption, MCFs, Kinetics, Thermodynamics, Hydrothermal method, Wastewater treatment