Batch adsorption of Mn2+ and Co3+ from Refinery wastewater using activated carbon from epicarp of Detarium microcarpum and Balanites aegyptiaca shells

Abstract

Refinery wastewater is a rich source of heavy metal ion contaminant and may not be safe if directly discharge to the environment without pre-treatment. This study seeks to implements application of various activated carbon adsorbents for the removal of cobalt and manganese ions from refinery waste water. The adsorbent produced include; ACDMPA (Activated carbon from Detarium microcarpum, using H₃PO₄ as activating agent), ACDMZC (Activated carbon from Detarium microcarpum, using ZnCl₂ as activating agent), ACBAPA (Activated carbon from Balanites aegyptiaca, using H₃PO₄ as activating agent) and ACBAZC (Activated carbon produced from Balanitea egyptiaca, using ZnCl₂ as activating agent). Influence of initial concentration, contact time, pH and adsorbent dosages were investigated and the results indicated that    optimum pH for the removal of Mn²⁺ by all the adsorbents was 2, while the optimum pH for the removal of Co³⁺ was 4 by ACDMPA and CAC. At pH 6, the maximum adsorption of Co³⁺ occur when ACDMZC, ACBAPA and ACBAZC was used. An equilibrium time of 30 minutes was required for the adsorption of Mn²⁺ and Co³⁺ by CAC, while 45 minutes was the equilibrium time for the adsorption of the two metal ions onto ACDMPA, ACDMZC, ACBAPA and ACBAZC. The optimum dosage for removal of Co³⁺ was 0.4g when CAC and ACDMPA was used, and 0.6g when other adsorbents were used. For Mn²⁺ the optimum dosage for its removal was 0.4g when ACDMPA was used, while 0.6g was the required optimum dosage for other adsorbents. The adsorbent produced were effective for the removal of Mn²⁺ and Co³⁺