Adsorption of 2,4-dichlorophenol on Mn-modified activated carbon prepared from Polygonum orientale Linn

Mn-modified activated carbon (PLAC-Mn) was prepared by impregnating Polygonum orientale Linn activated carbon (PLAC) with a MnNO3 solution. The feasibility of both PLAC and PLAC-Mn to remove 2,4-dichlorophenol (2,4-DCP) from an aqueous solution was examined. The absorbents were characterized by BET, XRD, FTIR and Boehm titration analysis. The influence of different parameters such as contact time, temperature, pH and ionic strength has been carried out. Property studies showed that impregnation with MnNO3 altered the structure of PLAC and Mn oxide was formed on the surface of PLAC-Mn. The 2,4-DCP adsorption capacity of PLAC-Mn was higher as compared to plain PLAC. The adsorption kinetic followed the pseudo-second-order equation for both adsorbents. The equilibrium data of PLAC was found to best fit to the Langmuir model, while PLAC-Mn was best explained by the Freundlich model. The adsorption of 2,4-DCP on both adsorbents decreased with an increase in pH. The ionic strength and desorption studies confirmed a chemical sorption mechanism.