Eco-friendly natural rubber–silver (NR–Ag) composites for photo-assisted degradation of methyl orange dye

An environmental friendly, low cost composite for the photo-assisted degradation of methyl orange (MO) is proposed. Here, natural rubber–silver (NR–Ag) composites are formed through soft thermal reduction. The characteristics of the NR–Ag composites were investigated using UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The deposition of Ag on the surface of natural rubber was proven by the XRD diffraction peaks, attributed to metallic Ag and the appearance of the surface plasmon resonance of Ag, at ~ 420–460 nm in the UV–vis spectrum. The degradation of MO dye by NR–Ag composite under UV light source showed positive results for the degradation of dye even with minute amounts of Ag content. The degradation mechanism of MO involved the generation of hydroxyl radicals from the UV-irradiated NR–Ag composite by the formation of superoxide species as the important radical intermediate. Several parameters such as the Ag salt concentration and pH of the MO dye were investigated. Complete degradation of MO was achieved when the composites containing 2 × 10−3 wt% of Ag (NR–Ag4) were employed at pH 3. Under this condition, complete degradation occurred within 30 min. Kinetic studies were conducted to understand the degradation phenomenon.