High flux photocatalytic self-cleaning nanosheet C3N4 membrane supported by cellulose nanofibers for dye wastewater purification

Hazardous dye substances discharged from the textile and dyestuff industries not only threaten local the surrounding ecosystems but are also hard to degraded. We report the preparation of process for a photocatalytic membrane device that can degrade dye pollution under visible light. This filtration membrane, with a well-organized multilayer structure, simultaneously achieves continuous and flow-through separation of degradation products. Cellulose nanofibers (CNFs) were used as a template for nanosheet C3N4 (NS C3N4) preparation; the performance for the photocatalytic degradation of dyes improved as the morphology changed from bulking to nanosheet. NS C3N4 was then attached to the surface of a prepared CNF membrane via vacuum filtration. This device exhibited high efficiency (the degradation rates of both Rhodamine B and Methylene blue both reached 96%), high flux (above 160 L.h(-1).m(-2).bar(-1)) and excellent stability (maintaining steady flux and high separation were maintained after 4 h). This easy-preparation, easy-scale-up, and low-cost process provides a new method of fabricating photocatalytic membrane devices for dye wastewater treatment.

Automated summary

This study presents a preparation process for a photocatalytic membrane device that can degrade dye pollution under visible light. By utilizing cellulose nanofibers (CNFs) and nanosheet C3N4 (NS C3N4) in a well-organized multilayer structure, the device achieved high efficiency, high flux, and excellent stability in dye wastewater treatment.