Kinetic and equilibrium modelling of cobalt(II) adsorption onto bagasse pith based sulphurised activated carbon

The applicability of sulphurised activated carbon (SAC) as adsorbent for the effective removal of Co(II) from aqueous solutions was investigated. Bagasse pith, a sugarcane industry waste, was used for the synthesis of SAC. Bench scale batch experiments were performed to study the effects of various parameters such as pH, contact time, initial concentration, temperature, ionic strength and adsorbent dose on the adsorption process. Maximum adsorption was observed at the pH range of 4.5–8.5. With an initial concentration of 50 and 100 mg dm−3 of the adsorbate at pH 6.0, the percentage adsorptions were found to be 90.3 and 81.0%, respectively. SAC showed a high adsorption capacity for Co(II) removal compared with laboratory and commercial grade activated carbons. Equilibrium studies were conducted to study the effects of initial concentration and temperature for the adsorption of Co(II) onto SAC. The results indicated that adsorption process obeys Langmuir isotherm model other than Freundlich model. An empirical relationship has been suggested to predict the percentage Co(II) removal at any time for known values of adsorbent dose and initial adsorbate concentration under the investigated conditions.