Adsorption Kinetics and Intraparticulate Diffusivities of Congo Red onto Kola Nut Pod Carbon

In this present study, the adsorption kinetics and intraparticulate diffusivities of congo red onto unmodified and modified kola nut pod carbons were studied. Two kinetic models, the pseudo first- and second-order equations, were selected to follow the adsorption process. Kinetic parameters, rate constants, equilibrium adsorption capacities, and correlation coefficients for each kinetic equations were calculated and discussed. Experimental results showed that the amount of congo red adsorbed by all the adsorbents increased with increasing contact time with NH4Cl modified kola nut pod carbon having the highest adsorption capacity as compared to the unmodified, heat- and HNO3-modified kola nut pod carbon. Results obtained also indicated that the adsorption of congo red onto kola nut pod carbons is pseudo first-order and the mechanism is particle-diffusion controlled.