Hydrothermal synthesis of mesoporous Mg3Si2O5(OH)(4) microspheres as high-performance adsorbents for dye removal

Water pollution has become one of the most urgent environmental issues to be solved for the global society, how to rapidly and efficiently dispose of dye such as RhB-contaminated effluents has become an imperative issue from an environmental point of view. In this contribution, uniform mesoporous Mg3Si2O5(OH)(4) microspheres (88.0% of which have a diameter of 1.22-1.78 mu m, S-BET = 281.68 m(2) g(-1)) consisted of nanosheets have been synthesized via a facile H3BO3 assisted cost-effective eco-friendly hydrothermal process (180 degrees C, 12.0 h), using abundant SiO2, MgCl2 center dot 6H(2)O, and NaOH as the raw materials. Based on the effects of process parameters, the H3BO3 assisted SiO2 template-formation mechanism is investigated in detail, and especially the key role of H3BO3 as the inorganic director/quasi surfactant is illustrated. When employed as the adsorbents for removal of RhB, the adsorption isotherm is well described by the Langmuir adsorption model, with the maximum monolayer adsorption capacities of 300.08 mg g(-1) (higher than most of the referenced adsorbents). Meanwhile, the intra-particle diffusion model also well fits to the kinetic data, suggesting the diffusion within the mesopores of the rate-limiting step. Moreover, the recycling performance reveals the as-obtained mesoporous microspheres as highly efficient adsorbents for removal of RhB with satisfactory chemical, morphological and structural stability.