Removal of Paranitrophenol from aqueous solution onto activated Carbons

In this study, the commercial powdered (PAC) and granular activated (GAC) carbons was tested as adsorbents for removing paranitrophenol (PNP) from aqueous solution. The batch adsorption experimental results indicated that the equilibrium time for PNP adsorption by commercial PAC and GAC was respectively 90 min and 120 min. The adsorption data was modeled by kinetic and equilibrium models. The pseudo- first (PFO) and second order (PSO) kinetic models were applied to fit the experimental data was assessed for describing the mechanism of adsorption. The data were found to be best fitted to the PSO model. The equilibrium study was performed using two models including Langmuir and Freundlich. The results revealed that the Freundlich isotherm fitted well the equilibrium data of PNP onto PAC and GAC. The adsorption for PAC was found to be feasible and spontaneous, with a removal capacity of PNP of more than 30 mg g^-1. With regard to the retention area, this removal capacity (30.98 μgPNP m^-2 PAC) was 79 % better than that GAC (6.55 μgPNP m-² GAC).