Polyurethane‐based nanocomposite for catalytic reduction of toxic dyes

Abstract

In this work, we prepared AuNPs loaded polyurethane‐sodium alginate (Au‐PU‐ALg) composite polymers by casting and in‐situ reduction method. Successful fabrication of AuNPs was confirmed by UV–visible, Fourior transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), field emission scanning elcetron microscopy (FESEM), and energy dispersive X‐ray (EDX) analysis along with the change in color of the suspension from yellow to dark purple. Thermo‐gravimetric analysis (TGA) also confirmed the loading of 7.44 % AuNPs of total nanocomposite contents. The catalytic activity of Au‐PU‐ALg nanocomposites was checked by reducing Rhodamine B (RhB) as a model reaction. It was seen that reduction of RhB was successfully done in the presence of NaBH4 and Au‐PU‐ALg nanocomposite in just 8 min with value of kapp found as 0.648 min−1. While the value of kapp for RhB reduction was found as 0.0008, 0.00221, and 0.0008 min−1 in the presence of catalyst, NaBH4 and polymer gel particles, respectively. Thus results show that the value of kapp for the reduction of RhB in the presence of NaBH4 and catalyst was found high as compared to the controlled reactions. Complex mixture of dyes such as RhB, crystal violet (CV), Congo red (CR), and dyes polluted industrial wastewater was become colorless in 10 and 3 min, respectively on mixing with catalyst and reducing agent. It was also observed that reduction of RhB followed pseudo first order kinetic model and Langmuir Hinshelwood mechanism.