Efficient photocatalytic decolorization of textile wastewater using Fe-Mo LDH/ZnO nanocomposite: A sustainable approach for environmental remediation

Abstract

The efficient treatment of dye-contaminated wastewater using environmentally friendly technologies holds considerable significance. This study delves into the synthesis of Iron-Molybdenum Layered Double Hydroxide/Zinc Oxide (Fe-Mo LDH/ZnO) nanocomposite using a hydrothermal technique and evaluating its performance in adsorption and photocatalysis for decolorizing textile wastewater under ultraviolet (UV) irradiation. The synthesized photocatalyst was characterized through various analytical techniques, including Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM), Energy dispersive X-ray spectroscopy (EDX), Elemental mapping, Vibrating sample magnetometer (VSM), Diffuse reflectance spectroscopy (DRS), Brunauer-Emmett-Teller (BET), Photoluminescence spectroscopy, and Transient photocurrent density analyses. Additionally, the study investigated the impact of different parameters such as pH, contact time, photocatalyst amount, and oxidant amount on dye removal efficiency using central composite design (CCD) experiments. Optimal conditions resulted in an impressive 97.50 % dye removal efficiency, achieved with 0.75 g/L of Fe-Mo LDH/ZnO, 0.095 M of sodium persulfate as the oxidizing agent, 156 min of contact time, and adjustment the pH of the wastewater to 3.1. The dye removal process followed pseudo-first-order kinetics, with a maximum adsorption capacity at 25 °C of 28.33 mg/g. Moreover, the photocatalyst maintained its efficiency over 5 cycles, showing no significant reduction in dye removal efficiency, which indicates its reusability and cost-effectiveness for practical applications. This research demonstrates the desirable potential of Fe-Mo LDH/ZnO nanocomposite as a highly efficient and environmentally friendly photocatalytic adsorbent for the treatment of dye wastewater, providing valuable insights for sustainable water resource management and pollution control strategies.