Construction of robust bienzyme-mimicking nanocatalysts for dye degradation by self-assembly of hematin, metal ions, and nucleotides

The growing proportion of the textile industry has led to an increase in the concentration of colored dyes in aquatic systems. Compared to traditional natural enzymes, enzyme-mimicking nanomaterials with higher stability and lower sensitivity have become a promising approach for dye removal. In this work, a simple and efficient method was described to synthesize hematin nanocomposites (hematin@Cu/GMP) for degradation of several dyes, such as orange G (OG), amido black 10B (AB), crystal violet (CV), patent blue VF (PB) and methyl orange (MO). The experimental data suggested that the hematin-based nanocomposite exhibited excellent binding affinity towards Cu2+ and GMP with no effect on the composite formation in the presence of chloride salts. Further, the bi-enzymatic activity of the discussed composite was evaluated against different substrates with performance relatively better than natural laccase and horseradish peroxidase. The catalytic activity of the hematin@Cu/GMP demonstrated excellent potential with 100% degradation efficiency for the said dyes. The composite furthermore demonstrated relatively better performance for the degradation of the OG dye with retained catalytic activity under harsh chemical conditions. Moreover, the composite demonstrated excellent reusability and stability against inorganic radicals including cations, anions, and other organic solvents. The bi-enzymatic activity and catalytic potential of the proposed nanocomposites are suggestive of their reliability for greener industrial applications.