Development of calcined catalytic membrane for potential photodegradation of Congo red in aqueous solution

Abstract

A novel approach to fabricate calcined catalytic membrane was developed through electrospinning of Co/TiO2–PVA solution on a polyethersulphone (PES) membrane sheet. The aim of this study was to develop and characterize a Co/TiO2–PVA nanofibre PES catalytic membrane and evaluate its potential application in the photocatalytic degradation of dye from an aqueous solution. Three materials namely Co/TiO2, calcined catalytic nanofibres and calcined catalytic membrane were prepared and characterized with SEM-EDS, FTIR, XPS, XRD, TGA, and UV–vis DRS. XPS and EDS spectra revealed successful incorporation of cobalt in our developed materials. SEM cross-section image of calcined catalytic membrane depicted three layers which could be attributed to bottom layer (PES membrane), PVA nanofibres (middle layer) and top layer (Co/TiO2). UV–vis DRS spectra of samples showed absorbance in the visible range (400 to 800 nm) indicating that these three materials can be used as photocatalysts. Tauc plots revealed low energy band gap 1.86 eV for calcined catalytic membrane. Of the three catalytic materials evaluated, the calcined catalytic membrane was observed to have the highest photocatalytic activity. The preliminary data revealed complete (100%) decolourisation of dye within 150 min when the calcined catalytic membrane was used. Electron holes and hydroxyl radicals played the main role in the degradation process. LCMS results evinced the photodegradation of CR by revealing mass spectra of intermediate molecules. These findings provide valuable insight into the possibility that the calcined catalytic membrane developed during this study could be considered for further catalytic applications, especially in wastewater treatment.