Modelling, analysis and optimization of adsorption parameters for H sub(3)PO sub(4) activated rubber wood sawdust using response surface methodology (RSM)

Adsorption capacity of Cu super(2) super(+) from aqueous solution onto H sub(3)PO sub(4) activated carbon using rubber wood sawdust (RSAC) was investigated in a batch system. Kinetic and isotherm studies were carried out, the thermodynamic parameters like standard Gibb's free energy ( Delta G super(o)), enthalpy ( Delta H super(o)) and entropy ( Delta S super(o)) were evaluated. The pseudo-second-order model was found to explain the kinetics of Cu super(2) super(+) adsorption most effectively. The process optimization was performed through Central Composite Rotary Design using response surface methodology (RSM) by Design Expert Version 5.0.7 (STAT-EASE Inc., Minneapolis, USA). An initial concentration of 35mgL super(-) super(1), temperature of 26 super(o)C, carbon loading of 0.45g(100mL) super(-) super(1), adsorption time 208min and pH of 6.5 was found to be the optimum conditions for the maximum uptake of copper ions of 5.6mgg super(-) super(1) in batch mode.