Integration of Photo-Fenton Reaction and Membrane Filtration using Lignin@t-FeC2O4/g-C3N4 Nanofibers Toward Accelerated Fe(III)/Fe(II) Cycling and Sustainability

Photocatalysis water treatment without artificial energy is cost-effective, waste-free and sustainable. Coventional powder photocatalysts have tiny contact surfaces, low catalytic efficiency, and are difficult to recycle and reuse, restricting their usage. Herein, a Lignin@t-FeC 2 O 4 /g-C 3 N 4 material is developed by engineering hollow quadrangle t-FeC 2 O 4 and g-C 3 N 4 nanosheets on lignin membranes through facile impregnation coating and precipitation reaction. Fast mass transport, catalytic activity and accessibility characterize hollow tetragonal FeC 2 O 4 · 2H 2 O. TEM, SEM and FTIR show that lignin binds t-FeC 2 O 4 and g-C 3 N 4 . The g-C 3 N 4 nanosheets are uniformly wrapped on the surface of lignin fibers, and t-FeC 2 O 4 is loaded between them. This structure increases visible light absorption and active site-contaminant contact. The chain reaction produces extremely active hydroxyl radicals from hydrogen peroxide because the Lignin@t-FeC 2 O 4 /g-C 3 N 4 modules are rich inFe II , according to XPS. Transient photocurrent response curves and electrochemical impedance spectroscopy suggest a promoted charge migration and isolation at the redox reaction interface in the Lignin@t-FeC 2 O 4 /g-C 3 N 4 system. As a result, Lignin@t-FeC 2 O 4 /g-C 3 N 4 degrades 99% Rhodamine B within 40 minutes, and this performance is stable even under difficult conditions, such as low hydrogen peroxide concentration and high pH. This study combines lignin membranes with the photo-Fenton reaction, and thus provides new concept for the development and application of membranes and photocatalysis.