Polydopamine-coated carbon nanotube catalytic membrane with enhanced water decontamination and antifouling capability under photothermal assistance

The contest between membrane permeance and catalytic performance has limited the water treatment performance of current catalytic membranes. Herein, polydopamine-coated carbon nanotube (PDA@OCNT) membranes with unique photothermal conversion (75.4 degrees C, 1.4 kW m- 2) efficiency and peroxydisulfate (PDS) activation ability were fabricated, aiming to realize photothermally-enhanced PDS activation on membrane for enhancing its performance towards wastewater treatment. The PDA@OCNT membrane filtration coupled with photothermal-assisted PDS activation (MFPL) was able to achieve ultrafast sulfamethoxazole (SMX) removal (1.23 s-1) under a high membrane permeance of 1713.2 LMH/bar, whose performance was 3.9 and 4.6 folds higher than that of membrane filtration coupled with PDS activation alone (MFP) or membrane filtration alone (MF), respectively. Meanwhile, PDA@OCNT MFPL also effectively mitigated reversible and irreversible fouling caused by humic acid (HA) with the flux loss 1.5 or 1.9 folds lower than that of MFP or MF. The photothermal effect played crucial role in improving performance of PDA@OCNT catalytic membrane: On one hand, it improved PDS activation on PDA@OCNT catalytic layer via accelerating electron transfer from membrane to PDS, resulting in enhanced production of SO4 center dot-for pollutants oxidation; on the other hand, it enhanced membrane surface hydrophilicity and repulsion interaction between membrane and HA for efficiently weakening fouling propensity of membrane.