共查询到20条相似文献,搜索用时 31 毫秒
1.
Raulio M Pore V Areva S Ritala M Leskelä M Lindén M Rosenholm JB Lounatmaa K Salkinoja-Salonen M 《Journal of industrial microbiology & biotechnology》2006,33(4):261-268
The aim of the present work was to explore possibilities of photocatalytic TiO2 coating for reducing biofilms on non-living surfaces. The model organism, Deinococcus geothermalis, known to initiate growth of durable, colored biofilms on machine surfaces in the paper industry, was allowed to form biofilms
on stainless steel, glass and TiO2 film coated glass or titanium. Field emission electron microscopy revealed that the cells in the biofilm formed at 45°C under
vigorous shaking were connected to the surface by means of numerous adhesion threads of 0.1--0.3 μm in length. Adjacent cells
were connected to one another by threads of 0.5--1 μm in length. An ultrastructural analysis gave no indication for the involvement
of amorphous extracellular materials (e.g., slime) in the biofilm. When biofilms on photocatalytic TiO2 surfaces, submerged in water, were exposed to 20 W h m−2 of 360 nm light, both kinds of adhesion threads were completely destroyed and the D. geothermalis cells were extensively removed (from >107 down to below 106 cells cm−2). TiO2 films prepared by the sol-gel technique were slightly more effective than those prepared by the ALD technique. Doping of
the TiO2 with sulfur did not enhance its biofilm-destroying capacity. The results show that photocatalytic TiO2 surfaces have potential as a self-cleaning technology for warm water using industries. 相似文献
2.
Mifen Cui Shuai Pan Zhe Tang Xian Chen Xu Qiao 《Chemical Speciation and Bioavailability》2017,29(1):60-69
The composite TiO2/Mo-TiO2 were prepared by a modified sol-gel method. The prepared catalysts were characterized by X-ray diffraction, BET analysis, SEM, X-ray photoelectron spectroscopy, and UV–vis diffused reflectance spectroscopy techniques. The structural characterization results demonstrated that Mo was successfully doped into the TiO2 lattice and caused slight changes in the physiochemical properties. The UV–vis DRS showed a red shift of the adsorption edge to the visible region. The photocatalytic decomposition efficiencies of the catalysts were examined with toluene as a typical VOC in a continuous flow reactor. The photocatalytic activity of the n-n heterogeneous TiO2/Mo-TiO2 was greater than that of pure TiO2 and Mo-TiO2, and the catalyst containing a Mo/Ti mole ratio of 2.5% exhibited optimum photocatalytic properties. In general, a relative humidity of 35%, a higher oxygen content, a lower initial toluene concentration, and a higher UV intensity were beneficial for toluene decomposition. 相似文献
3.
Enzhou Liu Limin Kang Feng Wu Tao Sun Xiaoyun Hu Yuhao Yang Hanchen Liu Jun Fan 《Plasmonics (Norwell, Mass.)》2014,9(1):61-70
Ag-loaded TiO2 (Ag/TiO2) nanocomposites were prepared by microwave-assisted chemical reduction method using tetrabutyl titanate as the Ti source. The prepared samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N2 adsorption–desorption isotherms, UV–vis absorption spectrum, X-ray photoelectron spectrum, photoluminescence spectrum, and Raman scattering spectrum, respectively. Results revealed that Ag nanoparticles (NPs) were successfully deposited on TiO2 by reduction of Ag+, and the visible light absorption and Raman scattering of TiO2 were enhanced by Ag NPs based on its surface plasmon resonance effect. Besides, Ag NPs could also effectively restrain the recombination of photogenerated electrons and holes with a longer luminescence life time. In addition, photocatalytic reduction of CO2 with H2O on the composites was conducted to obtain methanol. Experimental results indicated that Ag-loaded TiO2 had better photocatalytic activity than pure TiO2 due to the synergistic effect between UV light excitation and surface plasmon resonance enhancement, and 2.5 % Ag/TiO2 exhibited the best activity; the corresponding energy efficiency was about 0.5 % and methanol yield was 405.2 μmol/g-cat, which was 9.4 times higher than that of pure TiO2. Additionally, an excitation enhancement synergistic mechanism was proposed to explain the experimental results of photocatalytic reduction of CO2 under different reaction conditions. 相似文献
4.
Ga?lle Carré Erwann Hamon Sa?d Ennahar Maxime Estner Marie-Claire Lett Peter Horvatovich Jean-Pierre Gies Valérie Keller Nicolas Keller Philippe Andre 《Applied and environmental microbiology》2014,80(8):2573-2581
This study investigates the mechanisms of UV-A (315 to 400 nm) photocatalysis with titanium dioxide (TiO2) applied to the degradation of Escherichia coli and their effects on two key cellular components: lipids and proteins. The impact of TiO2 photocatalysis on E. coli survival was monitored by counting on agar plate and by assessing lipid peroxidation and performing proteomic analysis. We observed through malondialdehyde quantification that lipid peroxidation occurred during the photocatalytic process, and the addition of superoxide dismutase, which acts as a scavenger of the superoxide anion radical (O2·−), inhibited this effect by half, showing us that O2·− radicals participate in the photocatalytic antimicrobial effect. Qualitative analysis using two-dimensional electrophoresis allowed selection of proteins for which spot modifications were observed during the applied treatments. Two-dimensional electrophoresis highlighted that among the selected protein spots, 7 and 19 spots had already disappeared in the dark in the presence of 0.1 g/liter and 0.4 g/liter TiO2, respectively, which is accounted for by the cytotoxic effect of TiO2. Exposure to 30 min of UV-A radiation in the presence of 0.1 g/liter and 0.4 g/liter TiO2 increased the numbers of missing spots to 14 and 22, respectively. The proteins affected by photocatalytic oxidation were strongly heterogeneous in terms of location and functional category. We identified several porins, proteins implicated in stress response, in transport, and in bacterial metabolism. This study reveals the simultaneous effects of O2·− on lipid peroxidation and on the proteome during photocatalytic treatment and therefore contributes to a better understanding of molecular mechanisms in antibacterial photocatalytic treatment. 相似文献
5.
Properties of nonvolatile and antibacterial bioboard produced from bamboo macromolecules by hot pressing 总被引:1,自引:0,他引:1
Shengbo Ge Lishu Wang Zhenling Liu Shuaicheng Jiang Xiongxiong Yang Wei Yang Wanxi Peng 《Saudi Journal of Biological Sciences》2018,25(3):474-478
Employing the antibacterial property of industrial bamboo vinegar (IBV) and the photocatalytic degradation of TiO2, bamboo macromolecules were pretreated and processed into nonvolatile and antibacterial bio board (NVABB). The NVABB was then analyzed by conducting Fourier-transform infrared spectroscopy, thermogravimetric analysis and differential thermal analysis. Results show that NVABB samples had average density of 0.96?g/cm3, which is appropriate for application. In terms of physical and mechanical properties, the best NVABB sample obtained from IBV, TiO2 and bamboo had an IBV pretreatment time of 10?min, 2% TiO2 and 1% bamboo charcoal. Fourier-transform infrared spectroscopy demonstrated that optimum conditions for hot pressing were a temperature of 170?°C, duration of 15?min and the addition of IBV and TiO2. Thermogravimetric analysis/differential thermal analysis curves suggest that the thermal degradation of NVABB was less than that of bamboo and that hot pressing obviously increased the thermal stability of HDBB samples. Analysis of the antimicrobial effect revealed that IBV pretreatment improves the antibacterial property of NVABB. 相似文献
6.
Background Purpose
Photocatalytic water splitting for hydrogen evolution is a potential way to solve many energy and environmental issues. Developing visible-light-active photocatalysts to efficiently utilize sunlight and finding proper ways to improve photocatalytic activity for H2 evolution have always been hot topics for research. This study attempts to expand the use of sunlight and to enhance the photocatalytic activity of TiO2 by N doping and Au loading.Methods
Au/N-doped TiO2 photocatalysts were synthesized and successfully used for photocatalytic water splitting for H2 evolution under irradiation of UV and UV–vis light, respectively. The samples were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), and photoelectrochemical characterizations.Results
DRS displayed an extension of light absorption into the visible region by doping of N and depositing with Au, respectively. PL analysis indicated electron-hole recombination due to N doping and an efficient inhibition of electron-hole recombination due to the loaded Au particles. Under the irradiation of UV light, the photocatalytic hydrogen production rate of the as-synthesized samples followed the order Au/TiO2 > Au/N-doped TiO2 > TiO2 > N-doped TiO2. While under irradiation of UV–vis light, the N-TiO2 and Au/N-TiO2 samples show higher H2 evolution than their corresponding nitrogen-free samples (TiO2 and Au/TiO2). This inconsistent result could be attributed to the doping of N and the surface plasmonic resonance (SPR) effect of Au particles extending the visible light absorption. The photoelectrochemical characterizations further indicated the enhancement of the visible light response of Au/N-doped TiO2.Conclusion
Comparative studies have shown that a combination of nitrogen doping and Au loading enhanced the visible light response of TiO2 and increased the utilization of solar energy, greatly boosting the photocatalytic activity for hydrogen production under UV–vis light. 相似文献7.
Feng Wu Xiaoyun Hu Jun Fan Enzhou Liu Tao Sun Limin Kang Wenqian Hou Changjun Zhu Hanchen Liu 《Plasmonics (Norwell, Mass.)》2013,8(2):501-508
TiO2 nanotube arrays (TiO2 NTs) were fabricated by anodic oxidation and then Ag nanoparticles (Ag NPs) were assembled in TiO2 NTs (Ag/TiO2 NTs) by microwave-assisted chemical reduction. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), photoluminescence spectrum (PL), UV–vis absorption spectrum (UV–vis), and Raman spectrum, respectively. The results showed that Ag NPs were well dispersed on the surface of TiO2 NTs with metallic state. The surface plasmon resonance (SPR) effect of Ag NPs could extend the visible light response and enhance the absorption capacity of TiO2. Furthermore, Ag NPs could also restrain the recombination of photo-generated electron–hole pairs of TiO2 NTs efficiently. The methylene blue photodegradation experiment proved that the SPR phenomenon had an effect on photoreaction enhancement. The results of photocatalytic water splitting indicated that Ag/TiO2 NTs samples had better photocatalytic performance than pure TiO2 NTs. The corresponding hydrogen evolution rate of Ag/TiO2 NTs prepared with 0.002 M AgNO3 solution was 3.3 times as that of pure TiO2 NTs in the test condition. Additionally, the mechanism of catalyst activity enhanced by SPR effect was proposed. 相似文献
8.
Dr. Chhavi Sharma Dr. Dinesh Singh Prof. Dr. Ritu Srivastava Prof. Dr. Shailesh Narain Sharma 《化学与生物多样性》2023,20(10):e202300714
In the present work, a bionanocomposite for plant crop protection was prepared by non-toxic biocompatible & biodegradable nanomaterials (Cellulose & TiO2) to utilize its synergistic effects against antimicrobial pathogens. The commercially available microcrystalline cellulose has been reduced to a nanometric scale regime using acid hydrolysis, while the standard TiO2 nano-powder of particle size ~20 nm has been used to prepare their nanocomposite (NC). The antibacterial studies via agar well diffusion method demonstrated that after 72 h of incubation, parent nanomaterials Ncell and TiO2 were not showing any activity against phytopathogens X. campestris pv. campestris, and Clavibacter while the nanocomposite's NC's were still effective depicting both bacteriostatic and bactericidal actions. However, the bacterial growth of biocontrol P. fluorescence was not affected by Ncell, TiO2 NPs and NC after 72 h of incubation. The antifungal testing results via poison food agar assay method suggest that the nanocomposite, along with Ncell and TiO2 NPs, exhibited strong inhibition of fungal growth of Phytophthora Spp at 0.125 mg/ml concentration while for F. graminearum, similar effect was observed at 0.25 mg/ml concentration. The nanocomposite has proved its potential by exhibiting longer & stronger synergistic effects against plant pathogens as a good antimicrobial agent for protection of agricultural crops. 相似文献
9.
《Saudi Journal of Biological Sciences》2019,26(7):1385-1391
Current exanimation reports, green fabrication of silver doped TiO2 nanoparticles (Ag/TiO2) using aqueous extract of Acacia nilotica as bio-reductant and assess its potential as antimicrobial and anticancer agent. The obtained spherical Ag/TiO2 were characterized by various analytical techniques including FTIR, (XRD), (FE-SEM EDS), and (TEM). Synthesized Ag/TiO2 demonstrated broad spectrum antibacterial and anticandidal activity. The order of antimicrobial activity was found to be E. coli > C. albicans > MRSA > P. aeruginosa. In addition, cytotoxicity and oxidative stress of Ag/TiO2 nanoparticles in (MCF-7) cells was also investigated. Outcomes of MTT assay showed concentration dependent reduction in cell viability. Further, synthesized NPs reduced the level of glutathione, induced ROS generation and lipid peroxidation in the treated cells. Therefore, it is envisaged that these spherical nanoparticles may be exploited in drug delivery, pharmaceutical, and food industry. 相似文献
10.
Photocatalytic disinfection using titanium dioxide: spectrum and mechanism of antimicrobial activity 总被引:2,自引:0,他引:2
The photocatalytic properties of titanium dioxide are well known and have many applications including the removal of organic
contaminants and production of self-cleaning glass. There is an increasing interest in the application of the photocatalytic
properties of TiO2 for disinfection of surfaces, air and water. Reviews of the applications of photocatalysis in disinfection (Gamage and Zhang
2010; Chong et al., Wat Res 44(10):2997–3027, 2010) and of modelling of TiO2 action have recently been published (Dalrymple et al. , Appl Catal B 98(1–2):27–38, 2010). In this review, we give an overview of the effects of photoactivated TiO2 on microorganisms. The activity has been shown to be capable of killing a wide range of Gram-negative and Gram-positive bacteria,
filamentous and unicellular fungi, algae, protozoa, mammalian viruses and bacteriophage. Resting stages, particularly bacterial
endospores, fungal spores and protozoan cysts, are generally more resistant than the vegetative forms, possibly due to the
increased cell wall thickness. The killing mechanism involves degradation of the cell wall and cytoplasmic membrane due to
the production of reactive oxygen species such as hydroxyl radicals and hydrogen peroxide. This initially leads to leakage
of cellular contents then cell lysis and may be followed by complete mineralisation of the organism. Killing is most efficient
when there is close contact between the organisms and the TiO2 catalyst. The killing activity is enhanced by the presence of other antimicrobial agents such as Cu and Ag. 相似文献
11.
A. Wouter Maijenburg Eddy J.B. Rodijk Michiel G. Maas Johan E. ten Elshof 《Journal of visualized experiments : JoVE》2014,(87)
Photocatalytically active nanostructures require a large specific surface area with the presence of many catalytically active sites for the oxidation and reduction half reactions, and fast electron (hole) diffusion and charge separation. Nanowires present suitable architectures to meet these requirements. Axially segmented Ag|ZnO and radially segmented (coaxial) TiO2-Ag nanowires with a diameter of 200 nm and a length of 6-20 µm were made by templated electrodeposition within the pores of polycarbonate track-etched (PCTE) or anodized aluminum oxide (AAO) membranes, respectively. In the photocatalytic experiments, the ZnO and TiO2 phases acted as photoanodes, and Ag as cathode. No external circuit is needed to connect both electrodes, which is a key advantage over conventional photo-electrochemical cells. For making segmented Ag|ZnO nanowires, the Ag salt electrolyte was replaced after formation of the Ag segment to form a ZnO segment attached to the Ag segment. For making coaxial TiO2-Ag nanowires, a TiO2 gel was first formed by the electrochemically induced sol-gel method. Drying and thermal annealing of the as-formed TiO2 gel resulted in the formation of crystalline TiO2 nanotubes. A subsequent Ag electrodeposition step inside the TiO2 nanotubes resulted in formation of coaxial TiO2-Ag nanowires. Due to the combination of an n-type semiconductor (ZnO or TiO2) and a metal (Ag) within the same nanowire, a Schottky barrier was created at the interface between the phases. To demonstrate the photocatalytic activity of these nanowires, the Ag|ZnO nanowires were used in a photocatalytic experiment in which H2 gas was detected upon UV illumination of the nanowires dispersed in a methanol/water mixture. After 17 min of illumination, approximately 0.2 vol% H2 gas was detected from a suspension of ~0.1 g of Ag|ZnO nanowires in a 50 ml 80 vol% aqueous methanol solution. 相似文献
12.
Ting Xia Wei Zhang James B. Murowchick Gao Liu Xiaobo Chen 《Liver Transplantation》2013,3(11):1516-1523
TiO2 has been well studied as an ultraviolet (UV) photocatalyst and electrode material for lithium‐ion rechargeable batteries. Recent studies have shown that hydrogenated TiO2 displayed better photocatalytic and lithium ion battery performances. Here it is demonstrated that the photocatalytic and battery performances of TiO2 nanocrystals can be successfully improved with a facile low‐temperature vacuum process. These TiO2 nanocrystals extend their optical absorption far into the visible‐light region, display nanometer‐scale surface atomic rearrangement, possess superoxide ion characteristics at room temperature without light irradiation, show a 4‐fold improvement in photocatalytic activity, and has 30% better performance in capacity and charge/discharge rates for lithium ion battery. This facile method could provide an alternative and effective approach to improve the performance of TiO2 and other materials towards their practical applications. 相似文献
13.
Jung Kon Kim Hack Sun Choi Eungbin Kim Young Sang Lee Yong Ho Kim Si Wouk Kim 《Biotechnology letters》2002,24(17):1397-1400
A novel and highly effective UV-TiO2 photocatalytic reactor was developed for killing microorganisms, including Escherichia coli. Among tested four types of TiO2-immobilized photocatalytic supporters (glass bead, muscovite bead, alginate bead, and TiO2 thin film coated quartz tube), the muscovite bead had a 99.9% percent bactericidal activity within 5 min along with permanent longevity. Adding air bubbles or H2O2 (<50 mg l–1) to the sample solution significantly enhanced the killing activity in that 100% percent of bacterial cells were killed within 3 min. 相似文献
14.
Sana Thabet France Simonet Marc Lemaire Chantal Guillard Pascale Cotton 《Applied and environmental microbiology》2014,80(24):7527-7535
We have investigated the antimicrobial effects of photocatalysis on the yeast model Saccharomyces cerevisiae. To accurately study the antimicrobial mechanisms of the photocatalytic process, we focused our investigations on two questions: the entry of the nanoparticles in treated cells and the fate of the intracellular environment. Transmission electronic microscopy did not reveal any entry of nanoparticles within the cells, even for long exposure times, despite degradation of the cell wall space and deconstruction of cellular compartments. In contrast to proteins located at the periphery of the cells, intracellular proteins did not disappear uniformly. Disappearance or persistence of proteins from the pool of oxidized intracellular isoforms was not correlated to their functions. Altogether, our data suggested that photocatalysis induces the establishment of an intracellular oxidative environment. This hypothesis was sustained by the detection of an increased level of superoxide ions (O2°−) in treated cells and by greater cell cultivability for cells expressing oxidant stress response genes during photocatalytic exposure. The increase in intracellular ROS, which was not connected to the entry of nanoparticles within the cells or to a direct contact with the plasma membrane, could be the result of an imbalance in redox status amplified by chain reactions. Moreover, we expanded our study to other yeast and filamentous fungi and pointed out that, in contrast to the laboratory model S. cerevisiae, some environmental strains are very resistant to photocatalysis. This could be related to the cell wall composition and structure. 相似文献
15.
Corina Văcăroiu Mădălin Enache Măriuca Gartner Gabriela Popescu Mihai Anastasescu Aurelia Brezeanu N. Todorova Tatiana Giannakopoulou Christos Trapalis Lucia Dumitru 《World journal of microbiology & biotechnology》2009,25(1):27-31
This work focuses on the photocatalytic performances and antibacterial activity of nitrogen doped TiO2 nanosystems with three and five layers obtained by a sol-gel route, followed by thermal treatment in oxygen or ammonia atmosphere
at temperatures between 400 and 1000°C. Subsequently, the antibacterial activity of the obtained nanosystems on the Escherichia coli cells are determined and discussed. The obtained results show a significant dependence of the functional performances on
the system’s composition. In particular, the antimicrobial activity of nitrogen-doped TiO2 films is correlated with the temperature of thermal treatment and illumination time with visible artificial light. 相似文献
16.
Katie Laird Elena Kurzbach Jodie Score Jyoti Tejpal George Chi Tangyie Carol Phillips 《Applied and environmental microbiology》2014,80(19):6031-6036
Legionnaires'' disease is a severe form of pneumonia caused by Legionella spp., organisms often isolated from environmental sources, including soil and water. Legionella spp. are capable of replicating intracellularly within free-living protozoa, and once this has occurred, Legionella is particularly resistant to disinfectants. Citrus essential oil (EO) vapors are effective antimicrobials against a range of microorganisms, with reductions of 5 log cells ml−1 on a variety of surfaces. The aim of this investigation was to assess the efficacy of a citrus EO vapor against Legionella spp. in water and in soil systems. Reductions of viable cells of Legionella pneumophila, Legionella longbeachae, Legionella bozemanii, and an intra-amoebal culture of Legionella pneumophila (water system only) were assessed in soil and in water after exposure to a citrus EO vapor at concentrations ranging from 3.75 mg/liter air to 15g/liter air. Antimicrobial efficacy via different delivery systems (passive and active sintering of the vapor) was determined in water, and gas chromatography-mass spectrometry (GC-MS) analysis of the antimicrobial components (linalool, citral, and β-pinene) was conducted. There was up to a 5-log cells ml−1 reduction in Legionella spp. in soil after exposure to the citrus EO vapors (15 mg/liter air). The most susceptible strain in water was L. pneumophila, with a 4-log cells ml−1 reduction after 24 h via sintering (15 g/liter air). Sintering the vapor through water increased the presence of the antimicrobial components, with a 61% increase of linalool. Therefore, the appropriate method of delivery of an antimicrobial citrus EO vapor may go some way in controlling Legionella spp. from environmental sources. 相似文献
17.
Decolorization and mineralization of reactive dyes by intimately coupled TiO2‐photocatalysis and biodegradation (ICPB) on a novel TiO2‐coated biofilm carrier were investigated in a photocatalytic circulating‐bed biofilm reactor (PCBBR). Two typical reactive dyes—Reactive Black 5 (RB5) and Reactive Yellow 86 (RY86)—showed similar first‐order kinetics when being photocatalytically decolorized at low pH (~4–5) in batch experiments. Photocatalytic decolorization was inhibited at neutral pH in the presence of phosphate or carbonate buffer, presumably due to electrostatic repulsion from negatively charged surface sites on TiO2, radical scavenging by phosphate or carbonate, or both. Therefore, continuous PCBBR experiments were carried out at a low pH (~4.5) to maintain high photocatalytic efficiency. In the PCBBR, photocatalysis alone with TiO2‐coated carriers could remove target compound RB5 and COD by 97% and 47%, respectively. Addition of biofilm inside macroporous carriers maintained a similar RB5 removal efficiency, but COD removal increased to 65%, which is evidence of ICPB despite the low pH. ICPB was further proven by finding microorganisms inside carriers at the end of the PCBBR experiments. A proposed ICPB pathway for RB5 suggests that a major intermediate, a naphthol derivative, was responsible for most of the residual COD, while most of the nitrogen in the azo‐bonds (? N?N? ) was oxidized to N2. Biotechnol. Bioeng. 2012; 109:884–893. © 2011 Wiley Periodicals, Inc. 相似文献
18.
In the last decades, extensive research on the effects of nano-TiO2 on plant systems and different microorganisms has confirmed its photocatalytic and antimicrobial activity. However, there is no report on its application in plant cell and tissue culture as well as its role in eliminating contaminating microorganisms in tissue culture. In this work, barley mature embryos were cultured in Murashige and Skoog medium with four concentrations (0, 10, 30, 60???g/ml) of TiO2 suspension in four repetitions. Quantitative and qualitative characteristics of calli were analyzed after each subculture. Data analysis for calli number in the first culture and callus size in all three cultures showed that the effect of treatment was significant at p?>?0.95. As a result, quantitative features such as callus color, shape, embryogenesis, etc. were completely similar in both control and TiO2 nanoparticle treatments; there is no doubt that TiO2 nanoparticles could dramatically increase callugenesis and the size of calli. As well, TiO2 nanoparticles are effective bactericides with an aseptic effect, causing no negative change in the quality of the callus. It is necessary to do more complementary works to identify mechanisms involved for the increased calli size and embryogenesis of explants in darkness. 相似文献
19.
Hyun-Jae Shin Byung-Hoon Kim Hyun Suk Seo Chun Sung Kim Joong-Ki Kook Gyeong-Taek Lim Dong-Lyun Cho Doman Kim Seung Ho Ohk Yeong-Mu Ko 《Biotechnology and Bioprocess Engineering》2009,14(4):531-535
Cochlodinium polykrikoides (C. polykrikoides) is one of the most harmful red tide dinoflagellates due to its great economic damage and compromising recreational opportunity
and public health. Titanium dioxide (TiO2) is known to be used as a photocatalyst for the control of the aquatic invasive algae under natural and artificial light.
The purpose of this study was to design a highly efficient continuous photocatalytic reactor with TiO2-coated alumina for the demonstrated efficient degradation of C. polykrikoides. TiO2 photocatalyst beads were prepared by sol-gel dip-coating method using titanium tetra iso-propoxide on alumina. After 40 min
of ultraviolet illumination time, the reduction of C. polykrikoides cell number was more than 80%. The degree of degradation of C. polykrikoides increased in a time-dependent manner in this novel reactor. The degradation begins with photocatalytic action by the oxidative
species of TiO2 on the protective cell structures of C. polykrikoides. 相似文献
20.
Guocheng Huang Dehua Xia Taicheng An Tsz Wai Ng Ho Yin Yip Guiying Li Huijun Zhao Po Keung Wong 《Applied and environmental microbiology》2015,81(15):5174-5183
The dual roles of capsular extracellular polymeric substances (EPS) in the photocatalytic inactivation of bacteria were demonstrated in a TiO2-UVA system, by comparing wild-type Escherichia coli strain BW25113 and isogenic mutants with upregulated and downregulated production of capsular EPS. In a partition system in which direct contact between bacterial cells and TiO2 particles was inhibited, an increase in the amount of EPS was associated with increased bacterial resistance to photocatalytic inactivation. In contrast, when bacterial cells were in direct contact with TiO2 particles, an increase in the amount of capsular EPS decreased cell viability during photocatalytic treatment. Taken together, these results suggest that although capsular EPS can protect bacterial cells by consuming photogenerated reactive species, it also facilitates photocatalytic inactivation of bacteria by promoting the adhesion of TiO2 particles to the cell surface. Fluorescence microscopy and scanning electron microscopy analyses further confirmed that high capsular EPS density led to more TiO2 particles attaching to cells and forming bacterium-TiO2 aggregates. Calculations of interaction energy, represented by extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) potential, suggested that the presence of capsular EPS enhances the attachment of TiO2 particles to bacterial cells via acid-base interactions. Consideration of these mechanisms is critical for understanding bacterium-nanoparticle interactions and the photocatalytic inactivation of bacteria. 相似文献