CuNPs-loaded amines-functionalized-SBA-15 as effective catalysts for catalytic reduction of cationic and anionic dyes

This work involves the preparation of mesoporous silica SBA-15 functionalized by different amines in order to stabilize the copper nanoparticles and using the obtained materials as catalysts for the catalytic reduction of methylene blue (MB) and Orange G (OG) dyes in simple and binary systems. The obtained results clearly show that the nature of the functionalized amines significantly influences the size, dispersion and content of copper nanoparticles (CuNPs). Ultrafine nanoparticles were obtained by mesoporous silica SBA-15 functionalized by triamine (Cu@SBA-3). Several parameters which influence the reduction reaction such as the mass of catalyst, the nature of catalyst, the concentration of NaBH₄ and the concentration of MB were investigated. The results showed that the material containing higher content and finer sizes of CuNPs was the best catalyst (Cu@SBA-3) for the reduction of MB dye. This catalyst showed a complete conversion of MB to Leuco-MB in a reaction time which does not exceed 3 min. The application of the catalyst Cu@SBA-3 for the reduction of OG dye in a simple and binary system (OG + MB) has shown encouraging results with selectivity via the MB dye. Lastly, the reuse of this catalytic system has shown interesting results during five successive cycles thus, confirming its stability.