Yanwu Zhang

Synthesis and antibacterial activity of copper-immobilized membrane comprising grafted poly(4-vinylpyridine) chains

Poly(4-vinylpyridine) (P4VP) brushes were grafted onto microporous polysulfone (PSF) membranes via surface-initiated atom transfer radical polymerization (SI-ATRP) and then immobilized copper (II) ions on the modified membrane. Copper-loaded membranes exhibited excellent antibacterial properties with the added advantage of repeated use. The chemical composition and surface morphology of the functionalized membrane was characterized by ATR-FTIR, XPS, SEM, and AFM. The results showed that P4VP brushes clustered to rod-shaped covering and the sub-layer of membrane maintained sponge-like structures at the same time. Additionally, the kinetic study of SI-ATRP reaction revealed that the chain length of P4VP brushes increased linearly as the polymerization time increased. The antibacterial effects of copper-loaded CMPSF-g-P4VP membrane against Escherichiacoli were examined and the antibacterial efficiency reached 100% when 2.49wt.% of copper (II) ions was immobilized on membrane. The presented results could serve as a good starting point for the fabrication of antibacterial CMPSF membranes for waste-water treatment applications.

Preparation and Characterization of a Novel Polyamide Charged Mosaic Membrane

Abstract A novel composite charged mosaic membrane (CCMM) was prepared via interfacial polymerization (IP) of polyamine [poly(epichlorohydrin amine)] and trimesoyl chloride (TMC) on the polyethersulfone (PES) support. Fourier transform infrared spectroscopy (FT-IR), environmental scanning electron microscopy (ESEM), atomic force microscopy (AFM) and water contact angle analysis were applied to characterize the resulted CCMM. The FT-IR spectrum indicates that TMC reacts sufficiently with polyamine. ESEM and AFM pictures show that the IP process produces a dense selective layer on the support membrane. The water contact angle of the CCMM is smaller than that of the substrate membrane because of the cross-linked hydrophilic polyamine network. Several factors affecting the IP reaction and the performance of the CCMM, such as monomer concentration, reaction time, pH value of aqueous phase solution and post-treatment, were studied. The pure water flux of the optimized CCMM is 14.73 L·m−2·h−1·MPa−1 at the operating pressure of 0.4 MPa. The values of separation factor a for NaCl/PEG1000/water and MgCl2/PEG1000/water are 11.89 and 9.96, respectively. These results demonstrate that CCMM is promising for the separation of low-molecular-weight organics from their salt aqueous solutions.