Zinc oxide nanorods-polypyrrole nanocomposite as an effective photocatalyst for methylene blue dye degradation

Abstract

Dye-contaminated effluents pose a serious threat to the environment, making it essential to address this issue to support environmental sustainability. The conventional methods for removing such pollutants include adsorption, flocculation/coagulation, ion exchange, sedimentation, reverse osmosis, membrane filtration, chemical precipitation, and various chemical or electrochemical treatments are found to be costly and time-consuming. In recent decades, heterogeneous photocatalysis has gained attention as a promising alternative. In this study, zinc oxide (ZnO) nanorods will be synthesized on kanthal wires using the direct heating (DH) method (at 90 W for 60 min), chosen for its simplicity, low energy consumption, and cost-effectiveness. The resulting ZnO nanorods will then be coated with polypyrrole (PPy) via electropolymerization with various coating durations (1 and 5 min) to create a nanocomposite material. The optical and surface morphology characteristics of the ZnO/PPy nanocomposites will be examined using UV-Visible Spectroscopy (UV-Vis) and Field Emission Scanning Electron Microscopy (FESEM). Their photocatalytic performance will be assessed by degrading 10 ppm and 20 ppm of methylene blue (MB) dye under UV light. The study found that the ZnO coated with PPy in 1 min duration was able to degrade approximately 89.72% of a 10 ppm MB solution within 3 hrs, demonstrating its potential as an effective and eco-friendly solution for water purification. This study utilized a hybrid method combining direct heating for rapid ZnO nanorods synthesis and the systematic optimization of PPy coating time via electropolymerization in investigating its influence on morphology, optical properties, and photocatalytic performance to fabricate the nanocomposites, which is a novel and practical approach.