Effective adsorption of methylene blue from aqueous solution by coal gangue-based zeolite granules in a fluidized bed: Fluidization characteristics and continuous adsorption

Methylene blue (MB) pollution in wastewater has become an environmental problem. Batch and continuous adsorption experiments were performed to study the adsorption mechanism of MB by coal gangue-based zeolite granules in a fluidized absorber. The results showed that MB adsorption of coal gangue-based zeolite granules was mainly chemical adsorption in a fluidized bed , which was mainly affected by its size fraction ( d ), fluid velocity ( v ), bed weight ( m ), and initial concentration ( c o ). Under suitable operating conditions ( d  ≤ 0.5 mm, v  = 1.3 v mf (i.e., minimum fluidization velocity), m  = 100 g, and c o  = 100 mg/L), the fluidized bed formed by zeolite granules had the best adsorption performance for MB, with an adsorption saturation of 0.444 g/g and an equilibrium uptake of 108.041 mg/g, which is higher than that of the traditional packed bed. The results provide a theoretical basis for the industrial application of coal gangue-based zeolite granules.