Highly efficient and reusable mesoporous zeolite synthetized from a biopolymer for cationic dyes adsorption

A highly efficient and reusablezeolite was prepared using the biopolymer chitin as mesoporosity agent and applied to adsorb three cationic dyes. The zeolite was synthetized by the hydrothermal method and characterized. The potential of zeolite to adsorb crystal violet (CV), methylene blue (MB) and basic fuchsin (BF) was evaluated conducing kinetic, equilibrium, thermodynamic and regeneration studies. The treatment of simulated effluents was also performed. The modification with chitin biopolymer provided attractive adsorptive characteristics for the zeolite structure. The adsorption was attractive with adsorbent dosage of 2.0 g L-1 and pH of 7.5, 8.0 and 9.0, for CV, MB and BF, respectively. The adsorption kinetic was well described by the Homogeneous Surface Diffusion Model (HSDM). The equilibrium was adequately adjusted with the Langmuir (CV) and Sips models (MB and BF). Maximum adsorption capacities predicted by the isotherm models were 1217.3, 548.2 and 237.5 mg g(-1) for CV, MB and BF, respectively. The modified zeolite can be used for fifteen adsorption cycles maintaining the same adsorption capacity. Also, the adsorbent was able to treat a simulated textile effluent providing 85% of color removal. These results demonstrated that the synthetized zeolite is a highly efficient and reusable material to adsorb cationic dyes.