Removal of Lignin by Industrial Solid Wastes

Abstract

Batch experiments have been carried out to study lignin removal from pulp and paper mill effluent by adsorption onto blast furnace flue dust from a steel plant and slag generated in a chrome alloy plant. Removal efficiencies attained after 8 h were observed to be more than 80% and 60% for the blast furnace flue dust and slag, respectively. The adsorption processes for both adsorbents follow first-order kinetics and Freundlich adsorption isotherms, decreasing with the increasing pH and temperature. Intraparticle diffusion studies indicate that adsorption of the substrate takes place rapidly by external mass transfer, followed by intraparticle diffusion. Column experiments indicate that the absorbed amount of lignin decreased with increasing flow rate and decreasing bed height. The break through time and bed depth data showed the applicability of the bed-depth service time model.