Removal behavior of peat collected from Brunei Darussalam for Pb(II) ions from aqueous solution: equilibrium isotherm, thermodynamics, kinetics and regeneration studies

Peat collected from Brunei Darussalam shows a remarkable affinity toward Pb(II). Under optimized conditions of shaking time, settling time, pH and ionic strength, more than 95 % can be removed from a 10.0 mg L-1 Pb(II) solution using 0.050 g of peat at ambient temperature of 25 +/- 1 degrees C. Scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray fluorescence spectroscopy performed on peat samples before and after interaction with Pb(II) solution conclusively demonstrate the transfer of Pb(II) ions fromthe solution phase to the solid peat phase. Interaction of Pb(II) solution and peat follows pseudo-second-order kinetics and adsorption best fitted the Redlich-Peterson isotherm model. The maximum adsorption capacity (q(max)) was found to be 15mg g(-1). Thermodynamic parameters evaluated for the Pb(II)-peat system indicate that the above adsorption reaction is spontaneous and endothermic. Regeneration of Pb(II)-loaded peat is effective with HCl solution and the regenerated peat can be reused for adsorption of peat.