Surface structure and phase separation mechanism of polysulfone membranes by atomic force microscopy

Antibacterial properties of F-doped ZnO visible light photocatalyst

“…The analysis shows that sample ZnO:TFA 1:1 contains 43.4% of oxygen, which is higher in comparison with other powders (36.3% for ZnO and 40.5% for ZnO:TFA 1:2). As reported previously, the excess oxygen (as defects levels) can be trapped in the grain boundaries of ZnO [27]. The elemental concentrations did not vary between prepared batches.…”

“…Furthermore it was noted that among various ZnO powders used in the experiment, powder ZnO:TFA 1:1 was the most effective against E. coli and S. aureus when the visible light was available (log red 2.88 and 4.62, respectively). Based on the studies performed by others [27][28][29][30][31], it is believed that when the light is not available, the primary toxic effect of ZnO on microorganisms can be associated with the release of zinc ions causing disruption of the cell membrane activity and the formation of intercellular reactive oxygen species, mostly H 2 O 2 [32][33][34][35][36][37]. Photocatalysts such as TiO 2 or ZnO activated by UV or/and visible light (Fig.…”

Improved Permeate Flux of PVDF Ultrafiltration Membrane Containing PVDF-g-PHEA Synthesized via ATRP

“…Table 2 described statistical values of average pore size of membranes. The reason that pore size distribution was measured by operating CFP is because accurate pore size distribution is not available to be measured by SEM on account of different coating thickness of membranes [24,25]. As the graft copolymer was added into the casting solution, the mean pore size was reduced.…”

Influence of membrane surface properties on initial rate of colloidal fouling of reverse osmosis and nanofiltration membranes

“…Recent studies have shown that membrane surface morphology and structure influence performance characteristics of membranes [1][2][3][4][5][6][7][8][9]. Hirose et al [9] suggested an approximately linear relationship between membrane surface roughness and permeate flux for crosslinked aromatic polyamide reverse osmosis (RO) membranes, where permeability increased with increasing surface roughness.…”

“…Various analytical techniques have been employed for elucidating specific physical and chemical surface properties of membranes, including Raman spectroscopy (structure) [1], electron spin resonance (solute mobility in membrane polymer matrix and pores) [1], AFM (surface morphology, structure, and pore size) [1][2][3][4][5][6][7][8][9], streaming potential (membrane surface zeta potential) [10,11], NMR spectroscopy (permeability) [5], contact angle [12], and X-ray photoelectron spectroscopy (XPS) for surface chemical functional groups [13,14]. Despite these efforts, however, the role of membrane surface properties in colloidal fouling of RO/NF membranes is still not well understood.…”