纳米二氧化钛(n Ti O2)在被人们广泛使用的同时,其潜在的环境影响也受到越来越多的关注。为深入探讨n Ti O2与环境中现有污染物的相互作用及生物效应,以斜生栅藻(Scenedesmus obliquus)为受试生物,按照毒性单位法、相加指数法和混合毒...纳米二氧化钛(n Ti O2)在被人们广泛使用的同时,其潜在的环境影响也受到越来越多的关注。为深入探讨n Ti O2与环境中现有污染物的相互作用及生物效应,以斜生栅藻(Scenedesmus obliquus)为受试生物,按照毒性单位法、相加指数法和混合毒性指数法,研究了n Ti O2与双酚A(BPA,一种常见的环境类雌激素)的联合毒性效应。结果显示,n Ti O2与BPA对S.obliquus生长的72 h半抑制浓度(EC50)分别为28.7 mg·L-1与1.81 mg·L-1。而n Ti O2与BPA共存时,在不同毒性比(4:1,3:1,2:1,1:1,1:2和1:3)下,其联合毒性作用(以BPA计)的72 h EC50值分别为2.198,1.58,1.153,0.428,0.306和0.189 mg·L-1。两者的联合毒性作用不仅仅是简单的相加,而是随着两者毒性比的变化,由拮抗作用转变为相加作用,继而转变为协同作用。这表明,n Ti O2进入环境后与现有污染物的毒性比(浓度比)可能是其联合毒性作用模式的一个重要影响因素。展开更多
The photocatalytic oxidation of gaseous chlorobenzene（CB） by the 365 nm-induced photocatalyst La/N–Ti O2, synthesized via a sol–gel and hydrothermal method, was evaluated. Response surface methodology（RSM） was u...The photocatalytic oxidation of gaseous chlorobenzene（CB） by the 365 nm-induced photocatalyst La/N–Ti O2, synthesized via a sol–gel and hydrothermal method, was evaluated. Response surface methodology（RSM） was used to model and optimize the conditions for synthesis of the photocatalyst. The optimal photocatalyst was 1.2La/0.5N–Ti O2（0.5） and the effects of La/N on crystalline structure, particle morphology, surface element content, and other structural characteristics were investigated by XRD（X-ray diffraction）, TEM（Transmission Electron Microscopy）, FTIR（Fourier transform infrared spectroscopy）, UV–vis（Ultraviolet–visible spectroscopy）, and BET（Brunauer Emmett Teller）. Greater surface area and smaller particle size were produced with the co-doped Ti O2 nanotubes than with reference Ti O2. The removal of CB was effective when performed using the synthesized photocatalyst,though it was less efficient at higher initial CB concentrations. Various modified Langmuir-Hinshelwood kinetic models involving the adsorption of chlorobenzene and water on different active sites were evaluated. Fitting results suggested that competitive adsorption caused by water molecules could not be neglected, especially for environments with high relative humidity. The reaction intermediates found after GC–MS（Gas chromatography–mass spectrometry） analysis indicated that most were soluble, low-toxicity, or both. The results demonstrated that the prepared photocatalyst had high activity for VOC（volatile organic compounds） conversion and may be used as a pretreatment prior to biopurification.展开更多
LaON,LaTiO and LaTiON films are deposited as gate dielectrics by incorporating N or/and Ti into La_2O_3 using the sputtering method to fabricate Ge MOS capacitors,and the electrical properties of the devices are caref...LaON,LaTiO and LaTiON films are deposited as gate dielectrics by incorporating N or/and Ti into La_2O_3 using the sputtering method to fabricate Ge MOS capacitors,and the electrical properties of the devices are carefully examined.LaON/Ge capacitors exhibit the best interface quality,gate leakage property and device reliability,but a smaller k value（14.9）.LaTiO/Ge capacitors exhibit a higher k value（22.7）,but a deteriorated interface quality,gate leakage property and device reliability.LaTiON/Ge capacitors exhibit the highest k value（24.6）,and a relatively better interface quality（3.1×10^（11） eV^（-1）cm^（-2））,gate leakage property（3.6 × 10^（-3） A/cm^2 at V_g = 1V＋V_（fb）） and device reliability.Therefore,LaTiON is more suitable for high performance Ge MOS devices as a gate dielectric than LaON and LaTiO materials.展开更多
文摘纳米二氧化钛(n Ti O2)在被人们广泛使用的同时,其潜在的环境影响也受到越来越多的关注。为深入探讨n Ti O2与环境中现有污染物的相互作用及生物效应,以斜生栅藻(Scenedesmus obliquus)为受试生物,按照毒性单位法、相加指数法和混合毒性指数法,研究了n Ti O2与双酚A(BPA,一种常见的环境类雌激素)的联合毒性效应。结果显示,n Ti O2与BPA对S.obliquus生长的72 h半抑制浓度(EC50)分别为28.7 mg·L-1与1.81 mg·L-1。而n Ti O2与BPA共存时,在不同毒性比(4:1,3:1,2:1,1:1,1:2和1:3)下,其联合毒性作用(以BPA计)的72 h EC50值分别为2.198,1.58,1.153,0.428,0.306和0.189 mg·L-1。两者的联合毒性作用不仅仅是简单的相加,而是随着两者毒性比的变化,由拮抗作用转变为相加作用,继而转变为协同作用。这表明,n Ti O2进入环境后与现有污染物的毒性比(浓度比)可能是其联合毒性作用模式的一个重要影响因素。
基金supported by the National Natural Science Foundation of China(No.21276239)the Program for Changjiang Scholars and Innovative Research Team in University(No.IRT13096)
文摘The photocatalytic oxidation of gaseous chlorobenzene（CB） by the 365 nm-induced photocatalyst La/N–Ti O2, synthesized via a sol–gel and hydrothermal method, was evaluated. Response surface methodology（RSM） was used to model and optimize the conditions for synthesis of the photocatalyst. The optimal photocatalyst was 1.2La/0.5N–Ti O2（0.5） and the effects of La/N on crystalline structure, particle morphology, surface element content, and other structural characteristics were investigated by XRD（X-ray diffraction）, TEM（Transmission Electron Microscopy）, FTIR（Fourier transform infrared spectroscopy）, UV–vis（Ultraviolet–visible spectroscopy）, and BET（Brunauer Emmett Teller）. Greater surface area and smaller particle size were produced with the co-doped Ti O2 nanotubes than with reference Ti O2. The removal of CB was effective when performed using the synthesized photocatalyst,though it was less efficient at higher initial CB concentrations. Various modified Langmuir-Hinshelwood kinetic models involving the adsorption of chlorobenzene and water on different active sites were evaluated. Fitting results suggested that competitive adsorption caused by water molecules could not be neglected, especially for environments with high relative humidity. The reaction intermediates found after GC–MS（Gas chromatography–mass spectrometry） analysis indicated that most were soluble, low-toxicity, or both. The results demonstrated that the prepared photocatalyst had high activity for VOC（volatile organic compounds） conversion and may be used as a pretreatment prior to biopurification.
基金supported by the National Natural Science Foundation of China(No.61274112)the Natural Science Foundation of Hubei Province(No.2011CDB165)the Scientific Research Program of Huanggang Normal University(No.2012028803)
文摘LaON,LaTiO and LaTiON films are deposited as gate dielectrics by incorporating N or/and Ti into La_2O_3 using the sputtering method to fabricate Ge MOS capacitors,and the electrical properties of the devices are carefully examined.LaON/Ge capacitors exhibit the best interface quality,gate leakage property and device reliability,but a smaller k value（14.9）.LaTiO/Ge capacitors exhibit a higher k value（22.7）,but a deteriorated interface quality,gate leakage property and device reliability.LaTiON/Ge capacitors exhibit the highest k value（24.6）,and a relatively better interface quality（3.1×10^（11） eV^（-1）cm^（-2））,gate leakage property（3.6 × 10^（-3） A/cm^2 at V_g = 1V＋V_（fb）） and device reliability.Therefore,LaTiON is more suitable for high performance Ge MOS devices as a gate dielectric than LaON and LaTiO materials.
