Rapid catalytic reduction of environmentally toxic azo dye pollutant by Prussian blue analogue nanocatalyst

Abstract

The release of toxic azo dyes pollutants in the environment from different industries represents a public health concern and a serious environmental problem. Therefore, the conversion of hazardous methyl orange (MO) azo dye to environmentally benign products is a critical demand. In this work, an eco-friendly Prussian blue analogue (PBA) was synthesized and its catalytic activity toward the reduction of MO was investigated. The PBA copper(ii) hexacyanocobaltate(III) (Cu<inf>3</inf>[Co(CN)<inf>6</inf>]<inf>2</inf>) was synthesized by a facile inexpensive chemical coprecipitation method without using hazardous solvents. The nanocatalyst was characterized using XPS, Raman, FTIR spectroscopy, and XRD. The chemical reduction of MO using NaBH<inf>4</inf> and the PBA as nanocatalyst was monitored by UV-VIS spectroscopy. Toxic MO was completely reduced in 105 s with a rate constant (k) 0.0386 s⁻¹ using only 10 μg of the PBA nanocatalyst. Besides the powerful catalytic activity, the nanocatalyst also showed excellent stability and recyclability for ten consecutive cycles, with no significant decrease in the catalytic performance. Therefore, the proposed PBA is a promising, stable, cost-effective, and eco-friendly nanocatalyst for the rapid elimination of hazardous azo dyes.