(280c) Engineering Reduced Graphene Oxide Membrane Via in-Situ Peracetic Acid Etching to Achieve Excellent Water Permeance for Highly Efficient Dye Recovery

Graphene oxide (GO) membranes have been extensively investigated for molecular-sieving membranes for dye removal from textile wastewater thanks to the adjustable channel size and featured water transport path. Owing to the excellent dispersibility of GO in water, they are often reduced or cross-linked to improve their stability on the membrane. However, reduced GO (rGO) leads to dramatically low water permeance. This study demonstrates an effective approach of in-situ chemical etching using peracetic acid (PAA) on the rGO membrane, enhancing water permeance while retaining the dye rejection. Specifically, rGO nanosheets were prepared using hydrozine in a solvation state and vacuumed filtrated onto a nylon substrate. Then different content of PAA was deposited on top of the rGO membrane surface for different amount time to get an etched rGO (ErGO) membrane. A typical 50 nm-thick rGO membrane shows water permeance of 20 LMH/bar and congo red (CR) rejection of 99.8%, while the ErGO-10min with the same thickness exhibits water permeance of 56 LMH/bar (a 1.8 times increase) with similar CR rejection of 99.7%. ErGO membranes with water permeance of 50–80 LMH/bar and multiple dye rejection over 99.0% are superior compared to state-of-the-art commercial NF membranes, and surpassing GO membranes reported in the literature. Moreover, the stability of the ErGO membrane was corroborated in a long-term continuous filtration test and the performance remained stable. Given the good resistance to aggressive chemical washing and its excellent performance, the ErGO membranes demonstrate its potential for practical dye removal applications.