Abstract
Herein, a facile and economically practical method was applied for the fabrication of an efficient catalyst. Sodium-alginate (5 wt%) was used for the preparation of hydrogel beads against calcium divalent cation, which immediately formed alginate-beads as soon as the drop touches the surface of the solution. Further, metal nanoparticles (MNPs) were loaded on the surface of Ca-alginate hydrogel beads for 24 h. MNPs template was reduced from M(+)oxidised state to its M(0)by NaBH4. The difference in catalytic efficiency impregnated with Fe, Ni, Cu, and Ag was investigated against different nitro-phenols (4-nitro phenol (4-NP), (2-nitro phenol) 2-NP, and (2,6-dinitrophenol)2,6-DNPs) and azo dyes, such as congo red (CR) and methyl orange (MO). The Ag-coated NPs showed high catalytic performance among different nitrophenols, CR, and MO as compared to other loaded MNPs. The apparent rate constant of 0.936,0.288, and 0.914 min(-1)was reported during the reduction of 4-NP, CR, and MO, respectively. Similarly, 4-NP, 2-NP, and2, 6-DNP were reduced with the rate constant of 0.734, 0.301, and 0.179 min(-1)respectively. Therefore, in both cases, the catalytic reduction of Ag-0-CaAlg-BDs catalyst was found efficient for 4-NP. The loaded MNPs were characterised by ATR-FTIR for investigating different functional groups. Furthermore, they were examined with FESEM, EDX, ICP-OES, and XRD which confirm the presence of adsorbed MNPs on the surface of CaAlg-BDs. Apart from the good catalytic ability, the Ag-0-CaAlg-BDs hydrogel beads were efficient and can be easily recovered and reused compared to other available catalysts.