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Silica-based porous materials are popular adsorbents and have achieved marked success. However, one of the main challenges is surface functionalization for obtaining better removal performances. Therefore, in this paper we developed a hollow silica adsorbent with a well-defined morphology via a sodium silicate route. Compared with the conventional silica-based porous adsorbents prepared by the modified Stöber method, the synthesized hollow silica support exhibits many advantages such as low-cost silica source, and using only industrial commodities as starting materials and water as solvent. Excitedly, the resulting matrix can be used as a powerful separation tool to deal with environmental pollution because it is easy to separate from wastewater simply by centrifugation without any modification. The experimental results of absorption and separation on the neutral red indicate that low-cost hollow silica supports can evidently increase dye loading and decrease the rate of dye desorbed in comparison to conventional hollow silica adsorbents obtained via the Stöber method. We exhibit the first example of constructing high ordered macroporous silica adsorbent by using a low-cost silica source. This silica-based macroporous material can be useful as a powerful separation tool to deal with environmental pollution because it is easy to separate simply by centrifugation without any modification. Interestingly, the absorption and separation for neutral red show that it can increase absorbent amount of dye and decrease the rate of dye desorbed in comparison to conventional hollow silica obtained via the Stöber method. [ABSTRACT FROM AUTHOR]

The preparation of hollow silica spheres via the sodium silicate route presents many advantages such as a low-cost silica source, and an environmentally friendly reaction system. Unfortunately, it is extremely hard to prepare the well-defined hollow silica spheres by using sodium silicate as the silica source owing to its rapid, disordered precipitation under the acid catalysis. As a result, we, in this paper, report a facile, economic, one-pot pathway for preparation of the ordered hollow silica spheres by employing a sodium silicate precursor. In this approach, the cationic polystyrene (CPS) templates can be first prepared via emulsifier-free emulsion polymerization by using the cationic monomer vinylbenzyltrimethylammonium chloride, then, the silica shells were attached on the surfaces of CPS particles via electrostatic interaction, finally CPS particles were in situ dissolved and removed by adding toluene to create ordered hollow silica spheres. Some modern techniques and instruments, including the transmission electron microscope, scanning electron microscopy, infrared spectroscopy, thermogravimetric analysis, and Brunauer-Emmett-Teller theory were employed to monitor and characterize the resulting hollow silica spheres. [ABSTRACT FROM AUTHOR]