Chitosan-coated cotton cloth supported copper nanoparticles for toxic dye reduction

A new route to fabricate cotton cloth (CC) as easily removable substrate for the synthesis of copper nanoparticles on its surface and its utilization in a toxic dye reduction is reported herein. A 1 wt% chitosan (Chi) aqueous solution was prepared and coated onto CC surface to prepare the ions affinity Chi-CC material. The Chi-CC was then kept in copper sulphate solution with three different concentrations (0.05 M, 0.1 M and 0.2 M) to interact with Cu²⁺ ions through -NH and -OH functional groups of the Chi chain. After sufficient time of the Cu²⁺ uptake, the Chi-CC was treated with 0.1 M NaBH₄ solution which turned its color indicating well organization of the adsorbed ions into Cu-nanoparticles. The bare CC, Chi-CC and Cu/Chi-CC were spectroscopically examined via scanning electron microscopy, X-ray diffractometry, energy dispersive X-ray spectroscopy and thermo-gravimetric analysis. Afterward, Cu/Chi-CC was used in the Congo red (CR) dye reduction by NaBH₄ as catalyst. The performance of the amount of the catalyst and its usage in a series of similar dye reduction was evaluated.