Highly efficient removal of methylene blue via hollow graphene-based magnesium silicate

Methylene blue (MB) has been a severe threat to the ecological environment and organismal health, and synthesizing effective adsorbents for MB adsorption becomes an urgent demand for environmental protection. Magnesium silicate (MgSi) has proven to be an efficient adsorbent for MB removal. A hollow bubble-wrap-like reduced graphene oxide/magnesium silicate (HG@MS) composite with high efficiency for MB removal was synthesized by template and hydrothermal method. Microsphere polystyrene was used as the template for fabricating bubble-wrap-like graphene oxide, while magnesium silicate is in situ growth on the surface of reduced graphene oxide. After removing the PS template, the hollow bubble-wrap-like HG@MS adsorbent was made, which was assigned to a large surface area (570 cm2/g). Such a high surface area provides abundant adsorption sites for MB, which resulted in the maximum adsorption capacity of 595.2 mg/g. Meanwhile, the adsorption of MB on the adsorbent follows the pseudo-second-order kinetic model and the Langmuir isothermal model. The desorption results reflected that HG@MS remains 86% adsorption capacities for 5 recycles, which confirms HG@MS is recyclable.