Application of zeolite MCM-22 for basic dye removal from wastewater

MCM-22 was employed as an effective adsorbent for removal of basic dyes including methylene blue, crystal violet, and rhodamine B from aqueous solution. The adsorption kinetics and isotherms were investigated. The adsorption capacity of MCM-22 for three dyes follows an order of MB > CV approximately RB. Kinetic studies indicate that the adsorption follows the pseudo second-order kinetics and the adsorption is a two-step diffusion process with film diffusion dominating the process. The adsorption isotherm can be well fitted by both the Langmuir and the Freundlich models. Thermodynamic calculations suggest that the adsorption of basic dyes on MCM-22 is an endothermic reaction.