Hydrothermal Synthesis of Multifunctional Biochar-supported SALEN Nanocomposite for Adsorption of Cd(II) Ions: Function, Mechanism, Equilibrium and Kinetic Studies

Facile hydrothermal synthetic technique was employed for the fabrication of SALEN grafted multifunctional nanocomposite biochar with the main aim of efficient and effective removal of cadmium (Cd). The elemental composition and structure of the composite and the cadmium loaded sorbent were characterized using EDX, FTIR and SEM. Variables affecting cadmium removal such as initial metal ion concentration, contact time and pH were investigated by batch experiment. Maximum adsorption capacity of ۸۲۲۰ mg/kg was obtained at optimal pH ۱۰ with percentage removal efficiency of ۹۹.۳۰ % for ۴۴۸۰ ppm initial metal ion dosage. Data simulated into the adsorption and kinetic models fitted well the Freundlich isotherm implicating multilayer adsorption – chemisorption process and pseudo-second –order kinetics as the rate limiting step. Critical examination of the adsorption mechanism showed that inner-sphere complexation, ion exchange, co-precipitation and electrostatic attraction are the main driving force in the mechanistic interaction of the SALEN Schiff base N۲O۲ surface functionalized nanocomposite biochar with cadmium. The new nanocomposite is of low cost, benign, effective and efficient for the removal of cadmium in comparison with industrial sorbents and other functionalized biomaterials and highly recommended for decontamination of cadmium polluted sites.

کلیدواژه ها:

Adsorption ، Cadmium ، Multifunctional biochar nanocomposite ، Functionalization ، Mechanism