A Combined Process for the Degradation of Azo-Dyes and Efficient Removal of Aromatic Amines Using Porous Silicon Supported Porous Ruthenium Nanocatalyst

Herein, we present a facile route for the preparation of porous silicon supported porous ruthenium nanoparticle system (Si@p-RuNP) for efficient removal of azo-based dyes and aromatic amines from wastewater. The synthesized nanoparticles were characterized using different analytical techniques including high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, powder X-ray diffraction, Brunauer-Emmett-Teller analysis, etc. The Si@p-RuNP nanocatalytic system exhibits dual catalytic behavior for the reduction of -N=N- bond and oxidation of aromatic amines in aqueous solution. The porous nanostructured Si@p-RuNP exhibits excellent degradation efficacy for Congo red dye (44 cycles in 1 h) as compared to its solid analogue Si@RuNP (24 cycles in 1 h) in the presence of NaBH4. Also, the present nanocatalyst mimics the peroxidase-like activity toward oxidation of various aromatic amines to their corresponding polyamines at pH 5.0 in the presence of H2O2 as an oxidant. Polyamines being insoluble in water offers a simple and convenient strategy for the elimination of water-soluble aromatic amines. The present process is convenient, efficient, and cost-effective and generates a small amount of solid waste as compared to the existing processes. Thus, we envision that the present unique nanocatalyst system can be useful for the removal of toxic amines from effluent toward solving the problem of textile-based industrial wastewater.