Kinetic and thermodynamic studies of adsorption of 4-chloro-2-nitrophenol on nano- Ti02

Adsorption capacity of 4-chloro-2-nitrophenol (4C2NP) onto nano-Ti02 from aqueous solutions wasinvestigated in a batch system by considering the effects of various parameters like contact time, nano-TiO2 dosage, initial pH and initial 4C2NP concentration. Optimum conditions for 4C2NP adsorptionwere found to be initial pH z 2, nano-TiO2 closer- 0.01 g and equilibrium time 1 h. The adsorptionkinetic data were analyzed using pseudo-first and pseudo-second order models. It was found that thepseudo-second-order kinetic model was the most appropriate model, describing the adsorption kinetics.The thermodynamic parameters such as AG°, MP and AS° were computed from the experimental data.These values show that the adsorption of 4C2NP onto nano-Ti02 is spontaneous and endothermic.