| Nowadays,membrane technologies have been widely used for water purification and desalination.However,for conventional polymeric membrane,severe biological fouling always exists along with the deposition and growth of microorganism at membrane surface,and results in the decrease of water throughput,membrane lifetime and filtered water quality.Developing membranes with both high permeability and antimicrobial capability has been demonstrated to be an efficient approach to address this biofouling issue.The main strategies are as follows:?1?the antimicrobial modification for polymeric membranes is often accomplished by incorporating biocidal metal or semiconductor nanoparticles into them;?2?stable inorganic membranes with multi-functionality are more attractive because of their excellent fouling-resistance and chemical stability.In this paper,we report a ceramic Cu/TiO2 filtration membrane for water treatment with high water permeate flux and visible-light promoted antibacterial activity,used for photo-catalysis and membrane filtration process.?1?Cu/TiO2-NB nanostructures composed of large amounts of small-size Cu nanoparticles evenly dispersed over the TiO2-NB surface were synthesized by a facile deposition-precipitation method;?2?ceramic Cux/TiO2-NB?x is the Cu content,wt%?nanoporous membrane was prepared via direct compression method;?3?the structure and composition of prepared membranes were characterized by SEM,EDS,TEM,HR-TEM,XRD,XPS and Uv-vis;?4?the evaluatuion of membrane Filteration;?5?study for the antibacterial activity and visible-light asisited of antibacterial activity of Cu/TiO2-NB membrane against Staphylococcus aureus S.aureus)and Escheichia coli?E.coli?.The detail contents are as follows;I.For Cu5/TiO2-NB,the Cu particle sizes are about 3-5 nm,well dispersed on one dimensional H2Ti3O7-NB surface.And for Cu5/TiO2-NB membranes calcined under a high temperature of 800 °C,small Cu nanoparticles with sizes of 4-7 nm are well-dispersed on TiO2-NB surface.It clearly illustrates that Cu nanoparticles acted as binders to weld TiO2 nanobelts together enables the sintering of Cu/TiO2-NB ceramic membrane with enough mechanical strength at a lower temperature,such as 800 °C,and therefore makes the high porosity and small pore size accessible.2.It is shown that the Cu/TiO2-NB ceramic membrane prepared exhibited excellent permeability,which can efficiently filter out E.coli and S.aureus cells from bacterial suspension.For Cus/TiO2-NB membrane with a thickness of 0.6 mm,a large pure water flux of about 315 L/m2h was achieved under 1.0 bar.Obviously,the three-dimensional intersecting open pore structure of Cu/TiO2-NB membrane is beneficial for water to pass through.3.We presented that Cu/TiO2-NB ceramic membranes exhibited an effective inactivation for both E.coli and S.aureus cells regardless of visible light irradiation and the activity is tunable by changing the Cu loadings.In the dark,Cu5/TiO2-NB membrane-containing suspension showed a reduction of 84.5 ± 3%in viable bacteria for S.aureus after 15 min contact,and 100%inactivation was obtained within 45 min.In addition,a reduction of 77.3 ± 4%in viable cells was observed for E.coli suspension after in contact with Cu5/TiO2-NB membrane for 30 min and the complete inactivation was achieved within 60 min.Furthermore,the fast Cu-nanoparticle mediated contact-killing effect was also demonstrated by assessing the viability of bacterial cell attached on Cu/TiO2-NB membrane using live/dead fluorescent staining assay,as a result of no live cells,for both S.aureus and E.coli,on Cus/TiO2-NB membrane after incubation for 15 min and 30 min,respectively.Under visible light irradiation,plasmonic hot carriers from Cu nanoparticles further promote bactericidal effect.4.Hence,the inactivation of bacteria by Cu/TiO2-NB in the dark is suggested through contact-killing mechanism.The copper uptake can immediately cause cell damage,and simultaneously induce Cu ions release and generation of reactive oxygen species?ROS?,which will lead to further cell damage.When illuminated with visible light,hot electron-hole pairs can generate in Cu nanoparticles by nonradiative plasmon decay.The separated electrons and holes can react with H2O and O2 molecules,respectively,to yield reactive deleterious ROS?such as ·OH and O2-?,and thus enhance the inactivation of bacteria. |
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