Photocatalytic Cleanability of ZnO-Decorated Ceramic Membranes for Rhodamine B Removal

Area of Science:

• Materials Science
• Environmental Engineering
• Chemical Engineering

Background:

• Industrial effluents contain persistent organic contaminants like synthetic dyes, requiring advanced treatment methods.
• Conventional processes struggle with recalcitrant pollutants, driving interest in integrated systems.
• Photocatalytic membranes offer a dual approach for pollutant separation and degradation.

Purpose of the Study:

• To fabricate and characterize zinc oxide (ZnO) thin films on ceramic membranes for dye pollutant degradation.
• To investigate the effect of ZnO coating thickness on membrane performance and photocatalytic activity.
• To evaluate the efficiency of ZnO-coated membranes in degrading Rhodamine B (RhB) under UV irradiation.

Main Methods:

• ZnO thin films were deposited onto smectite-zeolite ceramic membranes (MS10/Z90) using spin coating with varying layers (M1, M2, M3).
• Membrane morphology and structure were analyzed using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD).
• Water permeability and photocatalytic degradation of Rhodamine B were assessed under UV light.

Main Results:

• Increased ZnO layers led to thicker, more homogeneous coatings with enhanced crystallinity.
• Water permeability decreased with increased ZnO layers, but degradation efficiency improved significantly (83.0% to 99.1%).
• Degradation followed pseudo-first-order kinetics, primarily driven by hydroxyl radicals (•OH).

Conclusions:

• ZnO layer thickness critically influences photocatalytic performance and mass transfer in ceramic membranes.
• The developed ZnO-coated ceramic membranes show high efficiency for dye pollutant degradation and potential for in situ regeneration.
• The membranes demonstrated operational durability with effective flux recovery after treatment.