Cu(II)-metalated Silica-based Inorganic-Organic Hybrid: Synthesis, Characterization and Its Evaluation for Dye Degradation and Oxidation of Organic Substrates

Abstract

A novel and efficacious inorganic-organic hybrid material was synthesized by immobilizing Cu(II)-Schiff’s base complex on silica-gel using 3-(2-aminoethylamino) propyltrimethoxysilane as linker and 1,3-diphenyl-1,3-propanedione for Schiff’s base formation. The hybrid was characterized by FT-IR, DRUV-Vis, Solid State 13C CPMAS NMR, Powder-XRD, SEM, ICP-AES, EDX and TGA and EPR techniques. Catalytic ability of the hybrid was evaluated for oxidative degradation of Reactive Black 5, and oxidation of few representative organic substrates, viz., tetralin, cyclohexane, cyclohexanol, and cyclopentanol, where the hybrid catalyst decomposes H2O2 to generate ·OH free radicals. Influence of various reaction parameters, i.e., H2O2 concentration, catalyst concentration, and temperature, on dye degradation process was studied and best reaction conditions for maximum degradation of RB5 were also determined. The catalyst gave a high dye degradation efficiency of 91 %, and a good product yield of 42.61 %, 41.09 %, 40.54 %, and 38.44 % for conversion of tetralin (with selectivity of 74.23 % and 25.77 % for tetralone and tetralol, respectively), cyclohexane (with selectivity of 75.05 % and 24.95 % for cyclohexanone and cyclohexanol, respectively), cyclohexanol (with 100 % selectivity for cyclohexanone), and cyclopentanol (with 100 % selectivity for cyclopentanone), respectively. Easy separation, reusability, and good catalytic activity leading to possible development of eco-friendly industrial manufacturing process are the motivating factors for using the synthesized novel material.

Keywords

• inorganic-organic hybrid
• silica gel
• catalysis
• reactive black 5
• hydrogen peroxide