Nickel Sorption onto Chitosan - Silica Hybrid Aerogel from Aqueous Solution

Abstract

The utilization and efficiency of agricultural waste-derived chitosan-silica hybrid aerogel “(CS)hA” on nickel removal from aqueous solution was examined and optimum parameters for pH, contact time, and initial ion concentration were determined during batch sorption system studies. Metal recovery was performed on the adsorbent using separately dilute concentrations of hydrochloric acid, acetic acid, ammonia, and sodium hydroxide solutions as eluents. The results generated were analyzed from kinetic and isotherm studies. The maximum Ni2+ adsorption of 99.78 % was established at 60 min and pH 3 in this study. The batch studies revealed that the percentage of nickel ion removal by the adsorbent decreased along with an increase in the initial Ni2+ ions concentration. The pseudo-second-order, the best fit of the kinetic model, has the values of its correlation coefficient “R2” ranging from 0.9 to 1, whereas the Langmuir model which had the maximum monolayer adsorption capacity of 85.84 mg g-1, was the best isotherm in interpreting the sorption process and the calculated separation factor was higher than 0 but less than 1. Dilute hydrochloric acid (0.1 M) was the best eluent in removing bound nickel ions (55.63 %) from (CS)hA.