Characterization of mesoporous magnesium silicate with hierarchical structure and its adsorption performance for dye and lead ion

Mesoporous magnesium silicate was prepared at 100 °C by hydrothermal method with the assisted template of mesoporous silica SBA-15 filled with carbon. The samples showed hierarchical structure composed of nanopetals and mesopores, specific surface area of 283 m2/g, as well as bimodal pore size distributions with the mean pore size of 3.5 and 5.0 nm. The obtained mesoporous magnesium silicate was utilized as an adsorbent for the removal of methylene blue and lead ions. The fast adsorption process of methylene blue was correlated well with the pseudo-second-order kinetics. The Langmuir isothermal model fitted the adsorption data of methylene blue and lead ion. The adsorption capacities for methylene blue and lead ion were determined to be 341 and 417 mg/g, respectively. In addition, after adsorption of methylene blue, hierarchical magnesium silicate with mesoporous structure was regenerated by calcination and still showed the adsorption capacity of 203 mg/g, which indicated its efficient reusability. This work presented an available route for the application of magnesium silicate as a promising adsorbent.