Modeling Mono- and Multicomponent Adsorption of Phenol and Cadmium from Aqueous Solution by Peanut Shell Biochar

In this work, the competitive adsorption of phenol and cadmium using the biochar of peanut shell (BPS) as an adsorbent was evaluated. The biochar was characterized as mesoporous and amorphous, with carbonyl and carboxyl groups, and pHPZC 7.9. The system reached equilibrium in around 180 min. For the single component equilibrium, the Langmuir-Freundlich model was the one that best represented the data with a maximum adsorption capacity of 16.32 mg center dot g-1 for phenol and 34.73 mg center dot g-1 for cadmium. For the binary mixture, the extended Freundlich and modified Redlich-Peterson models were the ones that presented the best adjustments, indicating the heterogeneity of the adsorption process. The results demonstrated the synergy of Cd2+ ions in phenol adsorption. The biochar presented potential for the removal of organic and inorganic substances simultaneously. The adsorption mechanism showed a limiting step on the surface of the BPS and greater access of Cd2+ to the adsorptive pores.