https://doi.org/10.3390/inorganics10070087
“Ordered hierarchical porous silica materials with micro/mesoporous structures were prepared using dextran as a template via the sol-gel technique. First, an aqueous–alcoholic dextran solution was prepared by mixing 36 mL of distilled water, 15 mL of ethanol, and 2.3 of g dextran. Subsequently, 9 mL of TEOS and 54 µL of HCl aqueous solution (0.67 mol/L) were dissolved in 30 mL of ethanol, and then this mixture was further added to the above mixture dropwise at room temperature. The resulting mixture was stirred at the preset temperature for 6 h. After cooling to room temperature, the solid products were filtered and washed several times. The final products were dried in an oven overnight at 120 °C. The dextran template was removed by calcination at 550 °C for 6 h. The reaction temperature was adjusted to 30, 50, and 80 °C, respectively. The obtained series of ordered hierarchical porous silica materials samples were labeled HSMs(D)-x, where x represented the different reaction temperatures of 30, 50, and 80 °C.
Ordered hierarchical porous silica materials were prepared using the dextran and CTAB dual template via the sol-gel technique. An aqueous–alcoholic dextran/CTAB solution was prepared by mixing 36 mL of distilled water, 15 mL of ethanol, and a certain amount of dextran and CTAB. The remaining steps followed those used for HSMs(D). The obtained products were labeled HSMs(DC)-y, where y = n_dextran/n_CTAB (y = 2, 0.5, 0.15, 0, representing the molar ratio of dextran/CTAB.
The modification of HSMs(DC)-0.15 hierarchical porous silica by amine groups was carried out by post-grafting and one-pot methods, respectively. The details of the procedure of the post-grafting method are as follows: in ethanol using (3-aminopropyl) triethoxysilane (APTES) or N-[3-(trimethoxysilane) propyl] ethylenediamine (NTPEA) as the amine source, 0.5 g silica was dispersed in 30 mL of ethanol under ultrasound for about 5 min. Afterward, 3 mL of APTES or NTPEA was added dropwise to the suspension. The resulting mixture was refluxed at 80 °C for 6 h under magnetic stirring. After cooling, the obtained solid was separated by centrifugation and washed with ethanol. The modified products were dried at 60 °C overnight and denoted as HSMs(DC)-0.15-APTES and HSMs(DC)-0.15-NTPEA.
Following the typical one-step co-condensation method, an aqueous–alcoholic dextran/CTAB solution was prepared by mixing 36 mL of distilled water, 15 mL of ethanol, and dextran/CTAB with a molar ratio of 0.15. After that, 10 mL of APTES was added dropwise to the aforementioned mixture, and then 54 µL of HCl aqueous solution (0.67 mol/L) was dissolved in this mixture. The remaining steps were in accord with those followed for HSMs(DC)-0.15, and the obtained product was labeled HSMs(DC)-0.15-NH2.”
