APPLICATION OF NANOSILICA FROM PALM KERNEL SHELLS FOR THE EFFECTIVE ADSORPTION OF CADMIUM IONS FROM AQUEOUS SOLUTIONS

Abstract

Water pollution and contamination has been a major challenge that mankind has been facing since the dawn of industrialization. One of these many pollutants are heavy metals which contaminate water, making it unfit for the activities of mankind. This study explores the potential of utilization of nanosilica obtained from palm kernel shells, an abundant and inexpensive agricultural waste product  as an adsorbent for the removal of heavy metals from water. The removal of cadmium, which is a heavy metal from water is crucial to prevent the adverse effects that comes with its consumption in the ecosystem, thus, silica nanoparticles obtained from Palm kernel shells were adopted to adsorb cadmium ions from an aqueous solution. The efficiency of cadmium ion removal from an aqueous solution was evaluated by carrying out batch adsorption studies under various parameters like temperature, time, concentration and dosage. The optimum initial concentration was seen to be 5ppm, the optimum contact time was 45mins, the temperature, 300C and the optimum dosage was 0.3g. Adsorption kinetics models (pseudo-first-order and pseudo-second-order) and isotherm models (Langmuir, Freundlich, and Temkin) were applied to analyze the experimental data  and to obtain the isotherm that best describes the study.From the results , it was observed to best fit the Langmuir model with a correlation factor of 0.9905 and the adsorption best fit the pseudo-second order kinetics model. All data on this study closely correlated with those from existing works. The study holds significant importance as it adopts nanosilica obtained from locally available agricultural by-product for the remediation of heavy metal contaminated wastewater, proving to be more simplistic, less energy intensive and safer for the environment than conventional wastewater treatment methods.