Synthesis of Amphiphilic Silica with High Exposure of Surface Groups and Its Utilization in Efficient Removal of Organic Dyes from Aqueous Solution

Amphiphilic silica is synthesized with the simultaneous introduction of two kinds of polar and weakly polar organic groups on its surface using a one-step reverse-phase microemulsion method. The obtained materials present as nanospheres with a size of ≈100 nm. A high percentage (≈80%) of silicon species can be exposed and the amount of surface Si  OH increased by above 50% with the introduction of organic groups. Plenty of groups, including polar groups (3-aminopropyl and hydroxyl) and weakly polar group (n-propyl) coexisting on the surface, enable the material to show amphiphilicity. This amphiphilic material can show an excellent property for the removal of various organic dyes from the aqueous solution, and the maximum adsorption capacity of Congo Red, Acid Blue 25, Reactive Blue 19, and Reactive Black 5 can reach 2453.1, 1157.7, 964.6, and 916.9 mg g −1 , respectively. Good reusability is also realized for the present amphiphilic material, which can be reused for at least three times. The reported work provides a successful example to prove that the surface hydrophilicity and lipophilicity can be simultaneously improved just through a simple introduction of certain organic groups, and then realize efficient removal of dyes from the polluted water.