Kinetic Study and Equilibrium Isotherm Analysis of Nickel (II) Adsorption onto Alginate-SBA-15 Nanocomposite

The present work was undertaken to evaluate the feasibility of nickel (II) removal from aqueous solution by adsorption onto a biopolymer adsorbent. The adsorbent was prepared using modification of mesoporous silicate SBA-15 with alginate biopolymer (alginate- SBA-15) by encapsulation method. Morphological structure of the obtained nanocomposite adsorbent was characterized by XRD, scanning electron microscopy, nitrogen porosimetry technique, and fourier transform infrared spectroscopy. Batch adsorption experiments were carried out to investigate influence of operational parameters such as pH, contact time and initial concentration on alginate-SBA-15 adsorption behavior. Kinetics study revealed that the pseudo-second-order model provided well mathematical description of the experimental data. Out of several isotherm models, the Langmuir, Ferundlich, Dubinin-Radushkevich, Redlich- Peterson, and Temkin models were applied to adsorption data to estimate adsorption capacity. The equilibrium adsorption data are well modeled by the Langmuir isotherm than the others and the maximum adsorption capacity found to be 58.82 mg g-1.