Design of hybrid g-C3N4/GO/MCE photocatalytic membranes with enhanced separation performance under visible-light irradiation

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2023-06, Vol.466, p.143164, Article 143164
• Main Authors: Pan, Junyang, Hua, Dan, Hong, Yiping, Cheng, Xi, Guo, Fangsong, Bing Tan, Kok, Zhong, Ziqi, Zhan, Guowu
• Format: Article
• Language: English
• Subjects: g-C3N4; Integrated photocatalysis-filtration process; Photocatalytic membrane; Wastewater treatment
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2023.143164

[Display omitted] •Hybrid g-C3N4/GO/MCE membranes were prepared by layer-by-layer assembling method.•Transition metal ions were doped into g-C3N4 to enhance photocatalytic performance.•Combined photocatalysis-filtration performance was presented by four parameters.•The membranes were optimized by adjusting the amount of GO and g-C3N4 nanosheets.•Photocatalytic membranes were highlighted by performance under varied irradiations. Photocatalytic membranes with concurrent catalytic oxidation and separating functions possess promising potentials for the degradation of organic pollutants in wastewater treatment. Herein, we designed a hybrid photocatalytic membrane (viz., g-C3N4/GO/MCE) by vacuum-filtration-assisted assembling method, consisting of graphitic carbon nitride (g-C3N4) nanosheets as a top layer, graphene oxide (GO) nanosheets as an interlayer, and commercial mixed cellulose ester (MCE) as a substrate layer. The microstructures, chemical compositions, and physicochemical properties of the designed g-C3N4/GO/MCE membranes were systematically characterized by a series of characterization techniques. Particularly, photocatalysis-filtration reactor cells were designed for the evaluation of the simultaneous separation and photocatalytic degradation performance in a single unit using both organic dyes and antibiotics as modeling pollutants in wastewater. Four parameters were adopted to represent the integrated photocatalysis-filtration performance of our designed photocatalytic membranes, including permeance (P), rejection (R’, filtration alone), removal (R, combined photocatalysis-filtration under light-irradiation), and degradation rate (D). The hybrid membranes showed superior permeance and solute removal under visible-light irradiation (300 W, λ > 420 nm), in which the permeance was 20% higher than that of no-irradiation conditions. In addition, 10 consecutive cycling tests and light-on/off cycles of the as-prepared g-C3N4/GO/MCE membrane toward RhB showed quite stable permeance in the range of 268.9 to 352.9 L h−1 m−2 bar−1, and the removal was maintained in the range of 88.4% to 95.4%, indicating excellent long-term stability. Remarkably, it also exhibited good removal performance of antibiotics (e.g., ofloxacin, norfloxacin, sulfamethoxazole, erythromycin, and roxithromycin). Accordingly, the designed hybrid g-C3N4/GO/MCE photocatalytic membranes with excellent photocatalytic activity and photocatalysis-filtration performance are promising for wastew