Bi2MoO6/纳米棒ZnO异质结对MB的可见光-压电协同降解性能研究

采用水热法合成了一系列不同负载率的Bi₂MoO₆/纳米棒ZnO复合光催化剂.通过XRD、FT-IR、SEM、TEM、XPS、UV-Vis、EPR和PL等分析技术对合成的样品进行表征.在光/超声波条件下,以亚甲基蓝（MB）为目标降解物评价其压电-光催化性能.结果表明：Bi₂MoO₆/ZnO纳米棒（BZ-0.6）的降解速率常数约为ZnO传统光催化的9.25倍,其性能提升的主要原因在于ZnO的压电效应与Bi₂MoO₆/ZnO界面形成的异质结的耦合,有效地促进了电子和空穴的分离和转移.此外,同实验条件下,循环利用5次后Bi₂MoO₆/ZnO复合光催化剂降解率仍保持良好的稳定性.     

Preparation, characterization and application of CuCrO2/ZnO photocatalysts for the reduction of Cr(VI)

The delafossite CuCrO₂ elaborated by sol-gel from 40 nm diameter colloid is optically active in the visible region. It is characterized physically and photoelectrochemically. The microstructure is fairly homogenous with a mean crystallite size of ca. 2 μm. The optical gap (1.30 eV), determined from the diffuse reflectance, is well suited to the sunlight spectrum. The Mott Schottky plot is characteristic of P-type conductivity with a flat band potential of -0.26 V_SCE. As application, the photoreduction of chromate is successfully achieved in air-equilibrated suspension CuCrO₂/ZnO (1/1). CuCrO₂ is photoactivated by visible light and the electrons in the conduction band (-1.34 V_SCE) are injected to ZnO. In the presence of salicylic acid, a conversion of Cr(VI) to Cr(III) of 57% is obtained under optimal conditions (pH 3 at 25℃, 5×10^-4 mol/L) because of the HCrO₄^- dark adsorption onto ZnO (4HCrO₄^- + 3C₇H₆O₃ + 18O₂ + 16H⁺ → 4Cr³⁺ + 21CO₂ + 19H₂O, ΔG⁰ = -557 kcal/mol). Prolonged illumination is accompanied by a deceleration in the photoactivity owing to the competitive water reduction, an issue of energetic concern. The hetero-system exhibits self sensitization for hydrogen production with an evolution rate of 149 μmol/(hr·g).     

H2O2 formation from photocatalytic processes at the ZnO/water interface

The paper focuses on the production of H2O2 by photocatalysis over ZnO in an aerated aqueous phase. The presence of different reductants that increase the H2O2 production in the aqueous phase is analysed; particular attention is paid to nitrite, which has been shown to be the reductant that produces the most significant increments in the H2O2 production. The photocatalytic anodic decomposition of ZnO in the presence of the different reductants is also investigated. From the results obtained, the relevance of the ZnO photocatalysis in the formation of environmental hydrogen peroxide is estimated.     

Cu/ZnO-RGO的抗菌性能及应用

采用溶胶-凝胶法制备铜锌复合氧化物（Cu/ZnO）,并将Cu/ZnO纳米粒子负载到还原氧化石墨烯（RGO）表面制备Cu/ZnO-RGO复合材料.对Cu/ZnO-RGO复合材料进行表征分析及抗菌性能考察,结果表明,Cu/ZnO纳米粒子成功负载在RGO表面,负载前后Cu/ZnO纳米粒子形态不发生改变,复合材料纯度较高.Cu/ZnO-RGO复合材料对大肠杆菌与金黄色葡萄球菌均有着优异的抗菌性能,可以破坏细菌细胞膜,导致细菌内容物流出,延长细菌进入对数生长期所需的时间.当RGO质量分数为15%?Cu/ZnO-RGO复合材料使用量为120μg/mL时,在循环冷却水系统中作用2h即可拥有96.76%的抗菌率.     

Ag／ZnO光催化降解甲基对硫磷研究

描述了掺杂体系Ａｇ／ＺｎＯ用于甲基对硫磷水溶液光催化降解,有氧存在下,经ＵＶ照射对甲基对硫磷光降解是有效的,并讨论了影响光降解中甲基硫磷诸因素,初步探讨了光降解机理和动力学,起始降解物为Ｃ２Ｈ６Ｐ＾＋Ｓ和Ｏ２ＮＨ４Ｏ,且是一级反应,半衰期为１．８２ｍｉｎ。     

Toxicological studies of zinc oxide nanomaterials in rats

In this study, we have evaluated the ability of zinc oxide (ZnO) nanoparticles to induce pulmonary and extrapulmonary toxicities was examined in rats following intratracheal (IT) instillation. Lungs of rats were instilled IT with either phosphate-buffered saline (PBS)?+?1% Tween 80, ZnO nanoparticles, carbonyl iron or quartz particles at a dose of 1 or 5?mg?kg^?1 body weight. Following exposure, bronchoalveolar lavage (BAL) fluid, blood samples and organs including lung, liver, kidneys, heart, pancreas, and brain were collected at 24?h, 1 week, or 1 month of post instillation of nanoparticles and different parameters estimated to assess toxicity. BAL fluid was analyzed for lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) to assess pulmonary toxicity. Exposures to ZnO or quartz particles produced transient dose-dependant increase in BAL fluid LDH and ALP activities at all post exposure periods. Blood samples were analyzed for the tissue damage biomarkers to assess extrapulmonary toxicity. Histopathological examination of lung, liver and kidneys revealed dose-dependent degeneration and necrosis which worsened at 1 week post-instillation periods but recovered at 1 month post instillation. Histopathological examination of rat pancreas, heart, and brain exposed to quartz or ZnO particles showed no marked changes. Data suggest the instillation of ZnO nanoparticles produced a greater pulmonary toxicity in rats comparable with quartz; and extrapulmonary toxicities of these ZnO nanoparticles might be due to translocation into liver and kidney.     

Dissolution of zinc oxide nanoparticles in exposure media of algae,daphnia, and fish embryos for nanotoxicological testing

Zinc oxide nanoparticles (ZnO NPs) are being widely investigated in a bioassay due to potential negative effects to biological receptor. The dissolution of metal nanoparticles such as ZnO NPs is crucial to interpret nanotoxicity results because ZnO NPs can release toxic-free ions in exposure media. In the present study, dissolution of ZnO NPs was evaluated in three selected synthetic media for aquatic toxicological testing: Elendt M4 daphnia medium, OECD algal medium, and fish embryo rearing solution. Both media are currently recommended for OECD testing for daphnia and algae. Time-dependent dissolution of ZnO NPs has been investigated in terms of sonication time to be used for the preparation of aqueous NPs suspension, and dissolution time corresponding to exposure period in toxicity testing. Since sonication is widely applied for NPs dispersion in the most of nanotoxicological testing, the emphasis of this study was on the dissolution of NPs as a function of sonication time. We also investigated the concentration-dependent dissolution of ZnO NPs. Our results demonstrated that dissolution of ZnO NPs was significantly affected by sonication and dissolution time, as well as NPs concentration. This study showed that parameters affecting dissolution of ZnO NPs should be considered in nanotoxicological testing.     

花瓣状ZnO光催化处理双酚A和Cr(Ⅵ)废水

以乙酸锌、柠檬酸三钠和氢氧化钠为原料,在室温下磁力搅拌制得ZnO。经XRD、SEM和TEM表征,ZnO具有良好的结晶度,为花瓣状形貌。在模拟太阳光的照射下,光催化反应80 min,ZnO对质量浓度为25 mg/L的双酚A溶液中双酚A的去除率仅为32.0%,对质量浓度为20 mg/L的Cr（Ⅵ）溶液中Cr（Ⅵ）的去除率为60.2%。将双酚A与Cr（Ⅵ）溶液混合后,ZnO对双酚A和Cr（Ⅵ）的去除率分别提高至77.6%和94.2%。     

ZnO包覆Al_2O_3的制备表征及光催化性能研究

采用化学沉积法制备了ZnO包覆Al2O3光催化剂,并通过X射线衍射(XRD)、扫描电镜(SEM)进行了表征。在自制的光化学反应器中,以中压汞灯作光源,一定浓度的甲基橙为光催化反应模型化合物,研究了光催化剂的活性。考察了甲基橙初始浓度、催化剂加投量、pH值、温度、光照强度、反应液体积等因素对脱色率的影响。实验结果表明,ZnO包覆Al2O3复合光催化剂具有较高的光催化活性。在250W中压汞灯下光照3h,0.10g复合光催化剂能使200mL,10mg/L甲基橙溶液的脱色率达到92.21%。     

光纤ZnO薄膜的制备及光催化性能研究

实验利用射频磁控溅射镀膜工艺,分别在光纤和石英玻璃上成功制备了ZnO薄膜。采用X射线衍射仪、原子力显微镜和荧光分光光度计对薄膜进行了测试分析,并对其光催化降解苯酚的性能进行了对比测试。结果表明,该薄膜具有良好的C轴取向性,光致发光峰分别位于362nm、421nm和486nm附近,且随着薄膜样品晶粒的减小而出现蓝移,光纤上ZnO薄膜的光催化能力是以石英玻璃为基底的ZnO薄膜的193倍,光催化效果显著。