Hybrid Alginate/TiO₂/Ag Bio-nanocomposite Beads for Catalytic Hydrogenation of 2-Nitrophenol

The current study emphases on formulating active hybrid bio-nanocomposite material based on biopolymer alginate embedded with TiO₂ and silver nanoparticles. A fixed amount of TiO₂ nanodispersion was mixed with alginate solution then the Alginate/TiO₂ bio-nanocomposite beads obtained by ionic crosslinking using CaCl₂ solution. The prepared Alginate/TiO₂ beads in the wet state loaded with Ag⁺ ions by adsorption technique then the Alginate/TiO₂ beads loaded with silver ions reduced to silver nanoparticles (Ag NPs) through irradiation technique. The bio-nanocomposite beads Alginate/TiO₂ and Alginate/TiO₂–Ag fully studied to assess the nanostructure morphology of embedded TiO₂ and Ag nanoparticles: size and shape. The catalytic ability of the prepared nanocomposite beads as a catalyst inspected by studying its ability on the reduction of 2- Nitrophenol (2-NP) to 2-Aminophenol (2-AP) under various factors including initial concentration of 2-nitrophenol, time of reduction process, content of reducing agent and amount of catalyst. It is found that the embedding of Ag nanoparticles has a great impact where the catalytic hydrogenation of 2-NP to 2-AP reached to 98% in case of using Alginate/TiO₂–Ag compared with 76% in case of applying hybrid Alginate/TiO₂ bio-nanocomposite as a catalyst. Also, the prepared hybrid bio-nanocomposite beads has a high reduction ability for 2-nitrophenol up to 0.05 M concentration. The optimum weight of catalyst was 0.4 g which accomplished nearly 98% reduction percentage.