SBA-15 organofuncionalizada com aminossilano como adsorvente para corantes reativos, utilizando planejamento fatorial

Abstract

This work reports the synthesis of the SBA-15 mesoporous silica the acidic hydrolisis of the tetraethylortosilicate (TEOS), and using the P123 pluronic copolymer (EO20PO70EO20). The precursor matrix was organically modified by silanization with the 3- trimethoxypropylsilyldiethylenetriamine, named as SBA-15-3N. The solids were characterized by low angle X-ray diffraction, CHN elemental analysis, N2 adsorption/dessorption measurements, absorption infrared spectroscopy, 29Si and 13C solid state nuclear magnetic resonance, scanning electron microscopy and transmission electron microscopy. Elemental analysis data indicated the amount of 1.53 mmol of nitrogen per gram of silica, which was confirmed by the infrared spectra. 29Si NMR showed the prevalence of T2 and T3 species in the solid SBA-15-3N. These data demonstrated the efficiency of the organofunctionalization of the SBA-15. The measurements of zeta potential showed that the SBA-15-3N has null surface charge at pH 9.2, favoring the adsorption of anionic dyes in a wide pH range. Finally, the SBA-15-3N was applied in the retention of the anionic dyes RN remazol blue and RG remazol yellow, using a factorial design to evaluate the agitation time, temperature and pH. The results showed that the SBA 15-3N was an efficient adsorbent for removing of the reactive dyes from aqueous solution. The use of experimental design was important to establish the optimized conditions, where the maximum retention capacities were 514 and 370 mg/g for RN remazol blue and RG remazol yellow, respectively, and both processes were fitted to Langmuir modified adsorption model.