Film pore diffusion modeling and contact time optimization for adsorption of distillery spentwash on fly ash

The contact time in two batch adsorbers were optimized using unreacted shrinking core model for the adsorption of biopolymeric pigments in distillery spentwash by fly ash adsorbent. The total optimal contact time obtained was 40 min for 3m(3) adsorbate volume having initial biopolymer concentration of 1.5mg/dm(3). The film pore diffusion model was used to determine the external mass transfer coefficient, effective diffusion coefficient, and bed capacity for continuous adsorption process. The adsorbent bed capacities at different initial biopolymeric concentrations (2,000, 5,500, 8,700, and 12,500mg/ml) are 69.26, 114.41, 143.64, and 172mg/g, respectively. The effective diffusion coefficients at various bed heights were determined for continuous adsorption process.