Novel, efficient and recyclable silica based organic–inorganic hybrid Nickel catalyst for degradation of dye pollutants in a newly designed chemical reactor

In this paper, a novel organic–inorganic hybrid heterogeneous catalyst was prepared through the immobilization of nickel tetrasulfophthalocyanine (NiTSPc) complex onto silica. The synthetic route is facile, cost effective and green. The catalyst was characterized by elemental analysis, diffuse reflectance UV–visible spectroscopy, 13C CPMAS and 29Si CPMAS NMR spectroscopy, X-ray diffraction (XRD), Scanning electron microscopy (SEM), BET surface area analysis, Energy dispersive X-ray fluorescence (ED-XRF) and Fourier transform Infrared (FT-IR) spectroscopic techniques. The catalytic performance of the novel organic–inorganic hybrid catalyst was evaluated in the oxidative degradation of azo dyes at room temperature using hydrogen peroxide as an environmentally benign oxidant. The conditions for maximum dye degradation were optimized in terms of catalyst loading, H2O2 dosage and initial pH of the solution. The dye degradation followed pseudo first order kinetics. GC–MS was used to analyze the products formed after the dye degradation. The hybrid catalyst showed up to 96% of degradation efficiency, and can be recovered and reused for multiple cycles without appreciable loss in its catalytic activity. In addition, a novel chemical reactor with automated modes has been designed for the first time which opens up a new avenue for the effective and large scale degradation of dyes at room temperature using recyclable organic-inorganic hybrid catalyst.

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► Synthesis of silica-based organic–inorganic hybrid Nickel catalyst.
► Large scale degradation of dyes in a novel chemical reactor with automated modes.
► Degradation followed pseudo-first order kinetics.
► Catalyst achieved degradation efficiency up to 96%.
► Reusability up to seven cycles without loss in its activity.