Preparation of hierarchical magnesium silicate with excellent adsorption capacity

Magnesium silicate (MS) is a widely used adsorbent, and much work has been done to control the surface morphology of MS to improve its adsorption capacity. In this work, hierarchical MS was prepared by combining hydrothermal process with freeze drying technique for potential application in adsorption. Firstly, the MS hydrogel was prepared by hydrothermal process, followed by replacement of water in hydrogel by tert-butyl alcohol. Finally, the MS was obtained by freeze drying. The prepared MS exhibited a rough and porous hierarchical structure having BET specific surface area and total pore volume of 530 m²/g and 0.90 cm³/g, respectively. MS was further used for methylene blue (MB) adsorption in aqueous solution and the adsorption data exhibited good correlation with the Langmuir adsorption isotherm model. The maximum adsorption capacity for MB was found to be 526 mg/g, far higher than the conventional adsorbents that popularly reported in literature. In conclusion, this work provides a novel route to prepare adsorbents with high adsorption performance.