Pb(II) Removal Process in a Packed Column System with Xanthation-Modified Deoiled Allspice Husk

The present research dealt with lead removal using modified Pimenta dioica L. Merrill as biosorbent in a batch and in continuous flow column systems, respectively. The allspice husk residues were modified first with a treatment through the xanthation reaction. For the adsorption tests, the atomic adsorption spectrophotometry method was used to determine the lead concentrations in the liquid samples. In the kinetic batch study (10mg of sorbent in 10mL of 25mg L-1 lead solution), the removal efficiency was 99% (adsorption capacity of 25.8 mg g(-1)). The kinetic data followed the pseudo-second-order model. The adsorption isotherm was fitted to the Freundlich model, where constants were K-f and 1/n (8.06 mg((1-1/n)) g(-1) L-1/n and 0.52), corresponding to adsorption capacities of 8 and 62 mg g(-1), at liquid equilibrium concentration of 1 and 50 mg L-1, respectively. In the continuous flow systems where lead solution of 50mg L-1 was treated in 2 columns of 5 cm (4.45 g) and 10 cm (9.07 g) bed heights, the dynamic adsorption capacity obtained by fitting the Thomas model was 29.114 mg g(-1) and 45.322mg g(-1), respectively.