Rapid pH-dependent Photocatalytic Degradation of Methylene Blue by CdS Nanorods Synthesized through Hydrothermal Process

Abstract

CdS nanorods were successfully synthesized using a hydrothermal method and their photocatalytic degradation activity was tested on methylene blue (MB) at different pH levels. The synthesis of CdS nanorods was confirmed using various techniques including UV–Vis and FTIR spectrometers, X-ray diffraction (XRD), dynamic light scattering (DLS), and high-resolution transmission electron microscope (HRTEM). UV–Vis analysis showed an absorption peak at 385 nm in the CdS nanorods suspension. FTIR spectroscopy revealed the presence of different functional groups responsible for stabilizing the nanorods. TEM analysis showed that the particles had a rod-like morphology with crystallite sizes ranging from 2 to 10 nm, consistent with the DLS studies. XRD analysis confirmed the crystalline nature of CdS. A photocatalytic reactor was used to degrade methylene blue at different pH values, and the residual concentration was monitored using UV–Vis spectroscopy. The photocatalytic activity of CdS nanorods was found to be improved by adjusting the pH of the solution. The nanorods showed high efficiency in degrading methylene blue, with degradation performance of approximately 32 % and 35 % after just 30 min under sunlight at pH 4 and pH 10, respectively. This research has potential applications in the photodegradation of harmful pollutants in both industrial wastewater and domestic water supplies.

Keywords

• CdS nanorods
• Photocatalytic degradation
• Photocatalysis
• Visible light
• Water pollutant