Biosorptive removal of cobalt (II) ion from wastewater using pomegranate peel activated carbon as biosorbent

Abstract

Cobalt is used to link the components during integrated circuits (ICs) fabrication. Cobalt ion is common in chemical mechanical planarization (CMP) spent slurry. The role of cobalt is indispensable in the semiconductor industry and its presence in the wastewater is inevitable. Cobalt metal ions are toxic heavy metals that can cause serious health issues such as heart disease, nausea, vision sterility, thyroid damage, bone defects and diarrhea. This work investigates the potential application of Punica granatum (pomegranate) peel-activated carbon (PPAC) as an adsorbent for cobalt metal ion removal by adsorption. The work also examines the influence of initial cobalt ion concentration, pH, contact duration and adsorbent dose on the removal efficiency (RE) and adsorption capacity (AC) of Co2+ and the results of the findings are discussed. The Co(II) adsorption kinetic study revealed that a pseudo-2nd-order is best fitted with a rate constant of ~0.00358 g mg-1 min-1. The adsorbent utilized in this work was assessed using SEM, EDAX, FTIR, XRD and TGA. EDX composition of post-adsorbent usage showed the presence of cobalt. Cobalt ion adsorption onto the PPAC was best fitted with the Freundlich isotherm model. Co(II) adsorption was found to be endothermic based on the thermodynamic characteristics evaluated for the carbon. At ambient temperature (~303 K) and neutral pH, PPAC was found to have a maximum AC of ~85 mg g?1 with a RE of ~90 %.