Effectiveness of industrial raw and demineralised Kraft lignins in removing a heavy metal species from dilute aqueous media

M. BETANCUR; P. R. BONELLI; J. A. VELASQUEZ; A. L. CUKIERMAN

Nancy, Francia

Congreso; Lignocarb Conference; 2007

ALFA EUROPEAID CO-OPERATION OFFICE, NANCY-UNIVERSITÉ, ENSTIB

The effectiveness of an industrial Kraft lignin and  of the sample prior subjected to a mild acid treatment in removing trace nickel from model solutions, mimicking low metal concentration wastewater, was comparatively investigated in an attempt to asses the effect of minerals inherently present in this by product from the pulping process in its metal sorption capability. Ash content, elemental composition, FTIR spectra, zeta potential, sodium uptake capacity, and amount of phenolic hydroxyl groups were determined for both the raw and acid treated lignin. From batch experiments, sorption kinetics and equilibrium isotherms were determined and modeled. Kinetic data for sorption of Ni(II) ions onto the industrial raw and demineralised Kraft lignins along with the predictions of reported pseudo-second order rate model, properly representing the experimental results for both samples are illustrated in Figure 1. Likewise as judged from conventional two, three-parameter isotherm models, reduction in mineral content of the raw lignin led to markedly improve the effectiveness in removing Ni(II) ion from the model solutions. The trend is consistently founded on changes in physicochemical features occasioned by acid pre-treatment of raw lignin.