Sorption Characteristics of Peat of Brunei Darussalam. II: Interaction of Aqueous Copper(II) Species with Raw and Processed Peat

This research was conducted to provide insight to the equilibrium and kinetics aspects of interaction of aqueous Cu(II) species with peat available in Brunei Darussalam. About 50% removal of Cu(II) from solution under optimized laboratory conditions at ambient pH was observed with raw peat. Acidification of peat with HNO3 solution as well as the treatment with diluted NaOH solution improve the extent of interaction resulting in a higher removal of about 70%, showing the complex nature of Cu(II) – peat interactions. Investigation of the extent of Cu(II) sorbed by raw, HNO3-treated and NaOH-treated peat as a function of equilibrium concentration indicates the agreement with the Langmuir isotherm for lower concentrations, fulfilling the requirement of the mono-layer coverage, followed by removal of more Cu(II) from the solution, which is equivalent to the multi-layer coverage, beyond the initial concentration of 200 mg L-1 Cu(II). Further, kinetics data obtained are in good agreement with the pseudo second order model with an average rate constant of 1.3 mol L-1 s-1.