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1.
The degradation of 17 beta-estradiol (E2) in water by TiO2 photocatalysis was investigated; concurrently the estrogenic activity of the treated water was evaluated during the photocatalytic reactions by an estrogen screening assay. As a result, 10(-6) M of E2 was totally mineralized to CO2 in 1.0 g L-1 TiO2 suspension under UV irradiation for 3 h. 10 epsilon-17 beta-Dihydroxy-1,4-estradien-3-one and testosterone-like species were elucidated as intermediate products by GC/MS analysis. The mechanisms of E2 degradation by TiO2 photocatalysis were discussed not only experimentally but also theoretically by calculating the frontier electron densities of the E2 molecule. On the basis of the results obtained, it was concluded that the phenol moiety of the E2 molecule, one of the essential functional groups to interact with the estrogen receptor, should be the starting point of the photocatalytic oxidation of E2. This means that the estrogenic activity should be almost lost concurrently with the initiation of the photocatalytic degradation. Actually, the estrogenic activities of the intermediate products were negligible. TiO2 photocatalysis could be applied to water treatment to effectively remove natural and synthetic estrogens without producing biologically active intermediary products.  相似文献   

2.
TiO2溶胶光催化降解亚甲基蓝   总被引:2,自引:0,他引:2  
以钛酸四正丁酯[Ti(OC4H9)4]为前驱体,乙醇为溶剂,盐酸为催化剂,在20℃制备了有光催化活性的TiO2溶胶.在40 W紫外灯光照条件下,通过对亚甲基蓝的降解试验,研究了溶胶制备条件、溶胶用量、光照时间和亚甲基蓝溶液初始质量浓度与光催化效果的关系.试验结果表明:当Ti(OC4H9)4与H2O量比为1:100,20℃下陈化7 d,制得的TiO2溶胶对0.20g/L亚甲基蓝溶液的降解率达到97.5%,具有较好的光催化性能.  相似文献   

3.
以钛酸四丁酯为原料,空心玻璃微珠(beads)为载体,采用溶胶一凝胶法制备出TiO2/beads光催化剂,用浸渍法制备出CoPcS/TiO2/beads新型光催化剂.研究了利用TiO2/beads及CoPcS/TiO2/beads光催化剂降解水面漂浮植物油的最优条件.结果表明:(1)溶胶-凝胶法制备TiO2/beads的最佳条件为:空心玻璃微珠浸渍3次,450~550℃下焙烧2 h.用CoPcS对TiO2/beads进行改性时,TiO2/beads的最1圭浸渍时间为30 min.(2)在中性或酸性条件下,375 W中压汞灯光照2~3 h,TiO2/eads与CoPcS/TiO2/beads的最佳用量分别为3 g和1 g(植物油3 g),在此条件下,植物油的去除率都高达90%.(3)微量H2O2对TiO2/beads和CoPcS/TiO2/beads的光催化活性都有很大的提高.对于TiO2/beads催化剂,H2O2的最佳用量为5~11 mmol/L;对于CoPcS/TiO2/beads催化剂,H2O2的最佳用量为5~30 mmol/L.(4)新型光催化剂CoPcS/TiO2/aeads比TiO2/beads具有更好的除油性能.  相似文献   

4.
掺锌纳米TiO_2光催化性能研究   总被引:1,自引:0,他引:1  
以钛酸四丁酯、硝酸锌为主要原料,采用溶胶-凝胶法制备掺锌纳米TiO2微粒.以罗丹明B为目标降解物,考察了掺锌纳米TiO2粉体的光催化活性.结果表明:300℃焙烧4.5 h时,得到的催化剂活性最高.在紫外光照射下,催化效果明显优于太阳光照射(在紫外光下,pH值为2时,用1 g/L掺锌2.7%纳米TiO2光照70 min,罗丹明B的降解率接近100%;在太阳光下,pH值为10时,用4 g/L掺锌3.0%纳米TiO2光照120 min,罗丹明B的降解率达93%).  相似文献   

5.
This paper deals with the antibacterial properties of nonwoven Co/PET and PP fabrics and woven cotton fabrics treated with the pad-dry-cure (PDC) and electrospray processes. Firstly, the surface modification of nonwoven Co/PET and PP fabrics was carried out to obtain their hydrophilicity by RF-plasma system using acrylic acid as the monomer. Subsequently, Ag-doped TiO2 nanoparticles prepared by sol–gel and chemical reduction processes using titanium isopropoxide and silver nitrate as precursor were applied to the fabric samples by PDC and electrospray processes. The effect of different synthesis processes of the nanoparticles and various application processes on their antibacterial efficiency was investigated. After RF-plasma pretreatment, the absorbency properties of the fabric samples were measured. The antibacterial activity of fabric samples against Escherichia coli and Staphylococcus aureus was determined qualitatively and quantitatively according to AATCC Method 147 and AATCC Method 100, respectively. The microstructural characteristics and surface morphology of the fabric samples were investigated by SEM-EDX and FTIR-ATR analyses. These results suggest that Ag-doped TiO2 nanoparticles synthesized by the chemical reduction process imparted good and durable antibacterial activity to nonwoven Co/PET and PP fabrics and woven cotton fabrics for use in wall textiles.  相似文献   

6.
Ni2+-Co2+共掺杂TiO2光催化降解制浆黑液的研究   总被引:2,自引:0,他引:2  
通过sol-gel法制备掺杂Ni2 、Co2 和Ni2 -Co2 共掺杂的纳米TiO2,利用X-射线衍射(XRD)、透射电子显微镜(TEM)和紫外-可见光谱(UV-Vis)对样品进行表征.结果表明:400℃时,粒子平均粒径为10nm左右,Ni2 、Co2 离子共掺杂抑制纳米TiO.晶粒的成长,使TiO2的光谱响应范围向可见光拓展.在紫外光照射下,Ni2 、Co2 离子共掺杂的TiO2能有效提高光催化降解制浆蒸煮黑液的效果,反应8h,体系中的CODCr可由反应前的480mg/I降至192mg/l,色度去除率可达到88.7%.  相似文献   

7.
Au-loaded TiO2 (Au/TiO2) has been reported for the first time as a sonocatalyst. It was found that the catalyst Au/TiO2, with a low Au loading 0.5 wt % and under common and commercial frequency (40 kHz) ultrasonic irradiation, greatly accelerated both the discoloration and total organic carbon (TOC) removal of azo dyes such as orange II (Org II), ethyl orange (EO), and acid red G (ARG), as compared to bare TiO2 and nano-Au catalyst. About 80% TOC removal was achieved after complete discoloration of 2.5 x 10(-4) M Org II. H2O2 and H2 formation as well as their accumulation was greatly enhanced due to Au loading on TiO2. Both oxidative and reductive degradation intermediates have been detected, and thus the mechanism involves both enhanced oxidation and enhanced reduction via the accelerated formation of active *OH and *H radicals due to Au loading on TiO2, which is supported by electron spin resonance (EPR) and other evidence. The study provides an admirable way to raise the efficiency of sonication and to treat azo dye-containing wastewaters with sonocatalytic processes.  相似文献   

8.
以TiO2为催化剂,紫外灯为光源,对乳酸的光催化降解进行动力学研究.乳酸降解反应动力学拟合结果表明,降解动力学规律符合Langmuir-Hinshelwood动力学模型,反应速率常数k=0.0085g/(L·min),一级反应动力学模型与实验数据拟合较好,方差R2大于0.99,乳酸初始降解速率r0随乳酸初始浓度增大而增大.  相似文献   

9.
Sorption coefficients (K(COC)) between 17beta-estradiol (E2), 17alpha-ethinylestradiol (EE2) and size-fractionated colloidal organic carbon (COC) derived from two biological wastewater treatment facilities were quantified by fluorescence quenching. The two wastewater treatment systems included a full-scale activated sludge system (FSAS) and a membrane bioreactor (MBR). The K(COC) coefficients were highly variable and ranged between (<1 to 179) x 10(3) L/kgCOC for E2 and (<1 to 430) x 10(3) L/kgCOC for EE2 and were higher than expected from the analytes octanol-water partition coefficient. Correlations between the molar extinction coefficients measured at 280 nm (e280) and K(COC) coefficients were weak but stronger for E2 compared to EE2. Attempts at correlating sorption behavior with colloidal protein and polysaccharide concentrations were only marginally successful (r2 approximately 0.4). These low correlations suggest that aromatic content, protein, or polysaccharide concentration can not adequately explain E2 and EE2 sorption behavior to COC and that other fractions of the organic matter pool play an important role in binding. A substantial portion of the aqueous E2 and EE2 concentrations (up to 60%) may be associated with colloidal material, suggesting that COC may play a role in the fate and transport of E2 and EE2 during the activated sludge process.  相似文献   

10.
11.
Pentachloronitrobenzene is a fungicide that is degraded in anoxic soils and sediments through unknown processes that are often thought to be biologically mediated. The present research describes the kinetics for the abiotic reduction of this compound in aqueous Fe(II)/goethite systems at near-neutral pH values. The results provide evidence for a rate-affecting surface-association process rather than a direct (i.e., kinetically second-order) reaction with an adsorbed Fe(II) species. It is therefore likely that the iron oxide surface participates directly in the reaction. Furthermore, reduction is observed in the apparent presence of trace amounts of suspended iron oxide nanoparticles, formed in situ by the oxidation of Fe(II). Given that Fe(III) colloids and other nanoscale phases may occur in natural sediments, such abiotic reactions could significantly influence the environmental fate of nitroaromatic compounds.  相似文献   

12.
邓辉  蒋新 《纺织学报》2007,28(9):76-79,83
为了探讨Ti02晶粒形貌对光催化过程的作用规律,研究吸附法和浸渍法制备的TiO2光催化剂降解甲基橙的过程,并考察制备反应条件对催化剂形貌和活性的影响.通过剖析反应的基本过程后得出,扩散过程与表面反应过程耦合,催化剂活性与甲基橙浓度的相对高低决定反应过程的控制步骤,从而对表观级数产生影响.在催化剂活性的考评中发现,低Ti含量以及小粒径情况下影响光催化的关键因素是晶型,其次为含量、粒径.吸附法制备的光催化剂Ti含量高,粒径小,可控性好,具有比浸渍法制备的材料更好的催化性能.随着水量的增加,吸附相反应技术的优势越来越显著.  相似文献   

13.
Nanocomposites of titamium dioxide (TiO2) particles and biodegradable poly (butylene succinate) (PBS) were fabricated by melt-blending using a high-shear extruder. TiO2 particles were highly dispersed in the PBS matrix by high-shear processing, and the addition of TiO2 particles into PBS did not decrease its mechanical strength. The photocatalytic decomposition and biodegradable properties of the nanocomposites were evaluated by UV irradiation or enzymatic degradation methods in vitro. It was found that both the esterase enzyme and UV irradiation decomposed the nanocomposites. Photocatalytic decomposition of PBS clearly depended on the size and dispersibility of TiO2 particles in PBS polymer. Higher dispersibility and smaller size of TiO2 particles were effective on the photocatalytic oxidation of PBS. In addition, decomposition rate under a simultaneous UV irradiation treatment and immersion in an enzyme solution was higher than those under UV irradiation or immersion in an enzyme solution. These results indicate that the nanocomposites can easily be decomposed not only by an enzyme in soil or compost, but also by photocatalytic oxidation of TiO2 under sunlight.  相似文献   

14.
Some individuals have expressed concern about estrogens in food because of their potential to promote growth of estrogen-sensitive human cancer cells. Researchers have reported concentrations of estrogen in milk but few whole milk samples have been analyzed. Because estrogen associates with the fat phase of milk, the analysis of whole milk is an important consideration. The objectives of this study, therefore, were to quantify 17β-estradiol (E2) in whole milk from dairy cows and to determine whether E2 concentrations in milk from cows in the second half of pregnancy were greater than that in milk from cows in the first half of pregnancy or in nonpregnant cows. Milk samples and weights were collected during a single morning milking from 206 Holstein cows. Triplicate samples were collected and 2 samples were analyzed for fat, protein, lactose, and somatic cell counts (SCC); 1 sample was homogenized and analyzed for E2. The homogenized whole milk (3 mL) was extracted twice with ethyl acetate and once with methanol. The extract was reconstituted in benzene:methanol (9:1, vol/vol) and run over a Sephadex LH-20 column to separate E2 from cholesterol and estrone before quantification using radioimmunoassay. Cows were classified as not pregnant (NP, n = 138), early pregnant (EP, 1 to 140 d pregnant, n = 47), or midpregnant (MP, 141 to 210 d pregnant, n = 21) at the time of milk sampling based on herd health records. Mean E2 concentration in whole milk was 1.4 ± 0.2 pg/mL and ranged from nondetectable to 22.9 pg/mL. Milk E2 concentrations averaged 1.3, 0.9, and 3.0 pg/mL for NP, EP, and MP cows, respectively. Milk E2 concentrations for MP cows were greater and differed from those of NP and EP cows. Milk composition was normal for a Holstein herd in that log SCC values and percentages of fat, protein, and lactose averaged 4.9, 3.5, 3.1, and 4.8, respectively. Estradiol concentration was significantly correlated (r = 0.20) with percentage fat in milk. Mean milk yield was 18.9 ± 0.6 kg for the morning milking. The mean E2 mass accumulated in the morning milk was 23.2 ± 3.4 ng/cow. Likewise, using the overall mean concentration for E2 in milk, the mean E2 mass in 237 mL (8 fluid ounces) of raw whole milk was 330 pg. The quantity of E2 in whole milk, therefore, is low and is unlikely to pose a health risk for humans.  相似文献   

15.
金属共掺杂纳米TiO2对甲基橙的催化降解   总被引:8,自引:0,他引:8  
李和平  袁曹龙  张玉强  曹忠 《印染》2006,32(24):9-13
以硫酸钛、CoCl2·6H2O和FeCl3为原料,采用共沉淀法制备了掺杂不同量Co2+和e3+的TiO2纳米粒,通过X-射线衍射(XRD)、差热-热重(TG-DTA)和紫外-可见吸收光谱(UV-Vis)等分析手段对样品的晶体类型、光谱吸收特征进行了表征.结果表明,金属共掺杂TiO2纳米粒仍以锐钛矿相存在,粒子的粒径约为12 nm;Co2+和Fe3+掺入TiO2后,主要以替代的方式占据TiO2晶格中Ti4+的位置,并在TiO2禁带中产生掺杂能级,使原来位于380 nm的吸收带边红移至460 nm.以太阳光为光源,当Co2+掺杂量为0.025%,Fe3+掺杂量小于0.05%时,光催化剂TiO2的活性较高,对甲基橙的降解率接近100%.  相似文献   

16.
The combination of adsorption and heterogeneous photocatalysis has been investigated as a promising technology for the removal of organic water pollutants. A laboratory study of the removal and decomposition of 2-chlorophenol (2-CP) as a toxic organic pollutant was carried out under various conditions with an organophilized clay mineral (hexadecylpyridinium chloride-modified montmorillonite; HDPM) as adsorbent and Degussa P25 TiO2 as photocatalyst. Three different oxidation processes leading to the degradation of 2-CP were compared: direct photolysis, heterogeneous photocatalysis in a TiO2 suspension, and the decomposition of substrate adsorbed on HDPM in the presence of TiO2. Both the degradation of 2-CP and the formation of intermediates were analyzed by HPLC, the total organic carbon content and the total organic and inorganic chloride contents were measured to monitor the mineralization process, and X-ray diffraction and thermoanalytical measurements were made to characterize the hydrophobic clay adsorbent. The heterogeneous photocatalytic degradation of dissolved (2-CP/UV/TiO2) and desorbed 2-CP (2-CP/HDPM/UV/TiO2) appeared to be equally efficient, whereas direct photolysis of 2-CP was far less efficient in the oxidative destruction. HDPM proved to be a suitable adsorbent, capable of adsorbing toxic organics from water. It was demonstrated that the adsorbent (at relatively high concentration) did not decrease the rate of mineralization of 2-CP. The results confirmed that the adsorbent retains its structure and composition during the mineralization process, and thus it can be reused without regeneration. The combination of adsorption and heterogeneous photocatalysis studied may be an efficient and economical means of accumulating, removing, and oxidizing organic water contaminants, and its application is in accordance with the growing environmental demands.  相似文献   

17.
为了探讨纳米TiO2对锦纶染色性能的影响,采用活性染料雷马素艳蓝R在相同条件下,对负载纳米TiO2和未改性锦纶织物进行染色,测试它们的上染百分率,并借助扫描电镜和热重测试手段对染色刷洗前后的试样表面形貌和热学性能进行表征,测试织物的漫反射光谱、耐刷洗色牢度、耐摩擦色牢度、耐日晒和光泽度等性能。结果表明,负载纳米TiO2后锦纶的上染百分率小于未改性锦纶;刷洗后,负载纳米TiO2锦纶上的TiO2颗粒部分脱落;纤维热起始分解温度有所下降;紫外线吸收能力明显增强;耐刷洗色牢度、耐摩擦色牢度均为5级;日晒后K/S值降幅较小;两者光泽性变化不大。  相似文献   

18.
Several lines of evidence support the key role of estrogens in male fertility. Here, we investigate the regulation of the serine/threonine kinase Akt-1 in the frog (Rana esculenta) testis during the annual sexual cycle and, whether 17beta-estradiol (E2) exerts a role in the Akt-1 activity. Akt-1 has been shown to be the mediator of growth factor-dependent cell proliferation, survival, and metabolism in a variety of cell types. First, we demonstrate by immunohistochemistry, the presence of estrogen receptor-beta (ERbeta), and Akt-1 in the spermatogonia (SPG), spermatocytes (SPC), and spermatids (SPT). Western-blot analysis revealed that ERbeta isoform (molecular weight 55 kDa) was highly expressed in May (reproductive period) with respect to January and November (winter stasis); in parallel, Akt-1 (molecular weight 60 kDa) is highly phosphorylated (Ser-473) during the period of active spermatogenesis (May) compared with the winter stasis (January and November). In addition, in vitro experiments demonstrate that E2 treatment induces the activation of Akt-1, and this effect is counteracted by the anti-estrogen ICI 182-780. In conclusion, our data show that E2 induces Akt-1 phosphorylation (Ser-473) possibly via ERbeta in frog (R. esculenta) male germ cells.  相似文献   

19.
This study investigated an application of TiO2 photocatalyst sensitized with tris(4,4'-dicarboxy-2,2'-bipyridyl)ruthenium-(II) complex to CCl4 degradation under visible light irradiation. By injecting electrons from the photoexcited sensitizer to the conduction band, the sensitized TiO2 degraded CCl4 under the irradiation of lambda > 420 nm. The quantum yield of CCl4 dechlorination was about 10(-3). The dechlorination rate of CCl4 was reduced in the presence of dissolved O2 due to its competition for conduction band electrons. The photolysis rate was dependent on pH due to the strong pH dependence of the sensitizer adsorption on TiO2 surface with a maximum degradation rate achieved at pH approximately 3. A two-site Langmurian model successfully described the adsorption of the sensitizer on TiO2 particles. The monolayer coverage was achieved at the added sensitizer concentration of 10 microM at [TiO2] = 0.5 g/L. However, the photolysis rate of CCl4 showed a maximum at a sensitizer surface coverage of 0.3 monolayer. Since the photoinduced electron injection gradually depleted active sensitizer molecules on TiO2, sacrificial electron donors to regenerate the sensitizer were sought. 2-Propanol as an electron donor was efficient in the present RuIIL3/TiO2/CCl4 system, which showed no sign of deceleration in the dechlorination rate up to 6 h of irradiation.  相似文献   

20.
Human amniotic epithelial (HAE) cells have great potential for successful use in cell therapy, since they do not cause acute rejection upon allotransplantation. However, to date, HAE cells have not well been studied. We previously reported that HAE cells produce erythropoietin (EPO), which is known to be a regulator of hematopoiesis, and that the induction mechanism of HAE cells is unknown, although EPO production from HAE cells is not increased by hypoxia which induces several cell types to produce EPO. In this study, we determined whether female sex hormones, including progesterone and 17beta-estradiol, affect the EPO production of HAE cells. Bioactive measurement of EPO activity in the culture supernatants of HAE-SV40 cells, which were immortalized by transfection with a simian virus 40 large T antigen, revealed that EPO bioactivity was significantly increased by treatment with progesterone, but not 17beta-estradiol. Treatment of HAE-SV40 cells with progesterone transiently increased the EPO mRNA level by fivefold, while there was no change in response to 17beta-estradiol. Furthermore, the progesterone receptor (PR)-B was detected in both HAE cells and HAE-SV40 cells by Western blotting. These results suggest that EPO synthesis in HAE-SV40 cells is stimulated by progesterone, but not by 17beta-estradiol, and thus it is highly likely that the EPO synthesis of HAE cells is also regulated by progesterone.  相似文献   

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