COMPETITIVE ADSORPTION OF DYES ON ACTIVATED CARBON PREPARED FROM VEGETABLE FIBERS

This study aims at eliminating simultaneously the Methylene Blue (MB) and Red Methyl (RM) by adsorption on a new biosorbent prepared from the loofa cylindrica fibers. The competitive biosorption of both dyes was studied in batch system for the following parameters: initial dye concentration (C0) in the range of 20-200 mg/L, pH from 3 to 9.5, time of contact and a mass ratios r=RM/MB=1 and r=1/3. A kinetic study showed that the equilibrium time for low (20 mg/L) and moderate concentrations (100 mg/L) is shorter compared to high concentrations (150 mg/L and 200 mg/L). The maximum rates of adsorption 99.45% and 98% for the RM and the MB respectively were obtained at pH=7.45 and C0=20 mg/L for both dyes. However, the same adsorbent show a high affinity for the MB compared to RM. The adsorption process for both MB and RM is well represented by the kinetic model of pseudo second order. The results of the desorption study realized for both dyes revealed that the biosorbent prepared from the loofa cylindrica fibers can be successfully regenerated using an HCl solution (0.1 N).