BICARBONATE-TREATED PEANUT HULL CARBON FOR MERCURY(II) REMOVAL FROM AQUEOUS-SOLUTION

Activated carbon prepared from bicarbonate-treated peanut hulls (BPHC) has been used for the adsorption of Hg(II) over a range of initial metal ion concentrations (10-20 mg dm-3), agitation time (5-180 min), adsorbent dosage (5-120 mg 100 ml-1) and pH (1.5-10.0). Adsorption of Hg(II) increased with increase in its initial concentration from 10 to 20 mg dm-3 and the equilibrium time of adsorption increased from 75 to 90 min for a BPHC dose of 100 mg 100 ml-1. The process of uptake obeys both the Freundlich and Langmuir isotherms. The applicability of the Lagergren kinetic model has also been investigated. Quantitative removal of 20 mg dm-3 Hg(II) in 100 ml by 70 mg adsorbent was observed over a pH range of 3.5-10.0. A comparative study with a commercial granular activated carbon (CAC) showed that BPHC is 7 times more effective compared to CAC.