Improved poly(vinyl butyral) hollow fiber membranes by embedding multi-walled carbon nanotube for the ultrafiltrations of bovine serum albumin and humic acid

• PVB membranes are modified by embedding O-MWCNT.
• The hydrophilicity and permeation flux of modified PVB membrane are improved.
• The modified PVB membrane has much lower permeation resistances.
• The modified PVB membrane is easily regenerated after ultrafiltration.
• The mechanical properties of modified PVB membranes are evidently improved.

The modified poly(vinyl butyral) (PVB) hollow fiber membranes are fabricated via wet spinning method for the ultrafiltrations of bovine serum albumin (BSA) and humic acid (HA) solutions. The morphologies, dynamic contact angle, static adsorption, permeation performance and mechanical properties of the membranes were also characterized. The results indicate that with the addition of oxidized multi-wall carbon nanotube (O-MWCNT), the surface hydrophilicity and pure water permeation fluxes (PWFs, JW) of the modified PVB membranes are evidently improved. The modified PVB membrane (M-4) containing O-MWCNT has higher permeation flux than that of the bare membrane (M-2) without O-MWCNT in the ultrafiltrations of BSA and HA solutions. Furthermore, the membrane of M-4 has a lower flux reduction ratio (RFR), a higher flux recovery ratio (FRR) than that of M-2. After ultrafiltration, the fouled membrane of M-4 is easily regenerated. The Darcy’s Law analysis illustrates that the PVB membrane (M-4) containing O-MWCNT has much lower permeation resistances than M-2 due to hydrophilicity increasing and protein adsorption decreasing. Additionally, the mechanical properties of modified PVB membranes are evidently improved after embedding O-MWCNT.