Two-stage batch sorber design using second-order kinetic model for the sorption of metal complex dyes onto pine sawdust

Abstract

The sorption of metal complex dyes, metal complex blue (MCB) and metal complex yellow (MCY), onto pine sawdust in a batch sorber has been studied. A model has been used for the design of a two-stage batch sorber based on pseudo second-order sorption kinetics. The model has been optimized with respect to contact time in order to minimize total contact time to achieve a fixed percentage of metal complex dyes removal. Three simplified kinetic models including pseudo first- and second-order equation, and intraparticle diffusion equation were selected to follow the sorption process. Kinetic parameters, rate constants, equilibrium sorption capacities and related correlation coefficients, for each kinetic model were calculated and discussed. It was shown that the sorption of metal complex dyes could be described by the pseudo second-order equation. The equilibrium data fit well in the Langmuir isotherm. Results of two-stage batch sorber design studies show that the required times for the 90% efficiencies removal of metal complex dyes are 45.9 and 22.4 min for MCB and MCY, respectively.