Adsorption and reusability performance of hierarchically porous silica (MMZ) for the removal of MB dye from water

Abstract

Various industries are releasing dyes every year as waste water and causing different kind of problems to human beings and marine life. To overcome water pollution, various materials are available but still there is a great need of new materials and techniques. Herein, well-ordered micro-mesoporous silica, MMZ, was developed by combined dissolution and self-assembly strategy using ZSM-5 as silica-alumina source and CTAB as structure building unit. Different characterizations techniques such as N2 adsorption–desorption, XRD, SEM, TEM and elemental mapping distribution were utilized to characterize the structure and morphology of the samples. The application of both ZSM-5 and MMZ was investigated for the adsorption of methylene blue (MB) dye, and the influence of different factors affecting MB adsorption such as time of adsorption, pH of solution, initial MB concentration and adsorbent dosage were optimized. MMZ exhibited superior adsorption capacity towards MB dye from water compared with ZSM-5 due to strong electrostatic interactions. The equilibrium data for MB adsorption over MMZ well fitted to Langmuir equation, with a maximum monolayer capacity (qm) of 303 mg/g. The adsorption of MB could be best described by the pseudo-second order model. Moreover, the MB adsorption activity of MMZ can be well recovered with no major loss.