Composites beads based on FeO@MCM-41 and calcium alginate for enhanced catalytic reduction of organic dyes.

This work concerns the preparation of composite beads based on calcium alginate and FeO@MCM-41. In the first step, the material FeO@MCM-41 was prepared mechanically using several FeO contents, then was encapsulated by calcium alginate as a cross-linking matrix to give the composites MC@CA(x). The composite beads were used as catalysts for the reduction of MB and OG dyes in a simple system. Several parameters affecting the reduction reaction were investigated such as effect of the shape of composite beads, concentration of NaBH, FeO content, catalyst mass and initial concentration of dye. The obtained results showed a higher immobilization of FeO@MCM-41 in the alginate matrix leading to a high porous structure. The results showed that these catalysts have interesting catalytic activities towards the reduction of MB dye in which the reaction was more efficient with the catalyst containing a higher content of FeO. The MC@CA(1) aerogel catalyst was the best in terms of stability compared to its MC@CA(1) hydrogel counterpart. Finally, the MC@CA(1) aerogel composite was reused in five successive cycles, with a slight loss of its activity during the fifth cycle due to the slight leaching of iron in the reaction medium.