Superior catalytic reduction of methylene blue and 4-nitrophenol by copper nanoparticles-templated chitosan nanocatalyst

Abstract

We represent a copper nanoparticle (CuNPs)-templated chitosan (CS) nanocomposite as an effective catalyst for the catalytic reduction of aqueous hazardous organic micropollutants, which was synthesized via a facile in-situ reduction step of pre-chelated Cu2+ ions on CS hydrogel. The as-developed CuNPs-templated CS nanocatalyst was thoroughly characterized using several spectroscopic methods. The CuNPs-templated CS nanocatalyst demonstrated excellent catalytic efficiency in the rapid reduction of aqueous methylene blue (MB) and 4-nitrophenol (4-NP). The reduction rates were well-complied with the pseudo-first-order kinetics and the corresponding rate constant values were estimated as 0.389 and 0.187 min−1, respectively for MB and 4-NP, which were significantly greater than numerous reported metal-based catalysts. The nanocatalyst can easily be recycled without substantially falling catalytic activity for four successive cycles. Based on the facile synthetic approach and excellent catalytic activity, the CuNPs-templated CS nanocatalyst can be an ideal catalyst for reducing hazardous aqueous contaminants for environmental protection.

Keywords

• CuNPs-templated chitosan nanocatalyst
• Catalytic reduction
• Methylene blue
• 4-nitrophenol
• Recyclability