Migration of titanium dioxide from PET/TiO2 composite film for polymer-laminated steel

PET/TiO₂ composite film is the most widely used film for polymer-laminated steel, and the migration of TiO₂ is very important for the safety evaluation of its packaged food. Microwave digestion, wet digestion and dry ashing were used for pretreatment of composite film to determine the content of TiO₂ in composite film. Migration tests were carried out at 40°C, 60°C and 80°C 4% using acetic acid and 50% ethanol as the acid and ester food simulants. The migration amount of TiO₂ was determined by inductively coupled plasma optical emission spectrometry (ICP-OES). With increasing temperature and time, the migration of TiO₂ increased. In 4% acetic acid, the migration amount of TiO₂ at 40°C for 10 days was 1.88 mg kg^?1 and the migration amount at 80°C for 8 h was 3.32 mg kg^?1, indicating that the effect of temperature on migration was more obvious. Under the same conditions, the migration amount of TiO₂ in 4% acetic acid was greater than in 50% ethanol. X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimeter (DSC) were used to analyse the crystal structure, morphology, chemical groups and thermal properties of the film before and after the migration tests. The results showed that filmTiO₂ had a stable rutile type crystal structure and it was almost uniformly distributed. PET and TiO₂ were combined with strong chemical bonds. After TiO₂ migration, the crystallinity and the glass transition temperature (Tg) of the film decreased, but the change of melting temperature (Tm) was not obvious.     

CEH漂白废水的TiO2光催化降解

以P25型TiO2为光催化剂,在悬浮态流化床催化反应器中对CEH三段漂白废水进行r光催化降解研究.以CODcr为评价指标,考察了催化剂用量、体系pH值、光催化降解时间及通氧方式等对降解CEH废水的影响因素.结果表明,TiO2投加量、光催化降解时间、体系pH值以及通氧对CODcr的去除影响显著.当TiO2用量为1.0g/L、初始pH值4.0、连续通气条件下降解效果最佳,光催化降解4h后,CEH漂白废水中CODcr去除率可84.8%.     

Preparation of titanium dioxide (TiO2) from sludge produced by titanium tetrachloride (TiCl4) flocculation of wastewater

Sludge disposal is one of the most costly and environmentally problematic challenges of modern wastewater treatment worldwide. In this study, a new process was developed, which has a significant potential for lower cost of waste disposal, protection of the environment and public health, and yield of economically useful byproducts. Titanium oxide (TiO2), which is the most widely used metal oxide, was produced from the wastewater sludge generated by the flocculation of secondary wastewater with titanium tetrachloride (TiCl4). Detailed analyses were conducted to compare TiCl4, ferric chloride (FeCl3), and aluminum sulfate (Al2(SO4)3) flocculation. Removal of organic matter and different molecular sizes by Ti-salt flocculation was similar to that of the most widely used Fe- and Al-salt flocculation. The mean size of Ti-, Fe-, and Al-salt flocs was 47.5, 42.5, and 16.9 microm, respectively. The decantability of the settled flocs by TiCl4 coagulant was similar to that by FeC13 coagulant and much higher than that of Al2(SO4)3. The photocatalyst from wastewater (PFW) produced by TiCl4 flocculation was characterized by X-ray diffraction, BET surface area, scanning electron microscopy/energy dispersive X-ray, transmission electron microscopy, photocatalytic activity, and X-ray photoelectron spectroscopy. The resulting PFW was found to be superior to commercial TiO2 (P-25) in terms photocatalytic activity and surface area. The PFW as also found to be mainly doped with C and P atoms. The atomic percentage of the PFW was TiO(1.42)C(0.44)P(0.14).     

The state of nano-sized titanium dioxide (TiO2) may affect sunscreen performance

In the past several years, there has been a trend in the sunscreen/cosmetics industry to replace micron-sized titanium dioxide (TiO(2)) particles with nanoscale materials. The increased use of nanoscale TiO(2) has resulted in questions about these and other nanoproducts. This study examines the effects of using nanoscale TiO(2) on ultraviolet (UV) attenuation in simple to complex sunscreen formulations. UV light attenuation, product stability, and potential damage to the skin barrier were examined with both nanoscale and microscale TiO(2) particles. Results indicate that none of the formulations decreased the barrier function of the skin and the best UV attenuation occurs when the TiO(2) particles are stabilized with a coating and evenly distributed such as with non-agglomerated coated nanoscale materials. This indicates that nanoscale TiO(2) may have better efficacy while lacking toxicity.     

TiO_2纳米纤维制备及其在光催化领域的研究进展

简述了纳米TiO2的性质,分析了静电纺TiO2纳米纤维的发展历程和研究现状,评述了近年来TiO2纳米纤维在光催化领域中的应用进展,并对其发展前景进行了展望。     

镧掺杂TiO2光催化降解酸性红B的研究

采用溶胶-凝胶法制备了La^3＋／TiO2光催化剂,在模拟太阳光照射下,考察了该催化剂对酸性红B的光催化降解效果。结果表明：掺杂量ω（La^3＋）1％、催化剂用量1g／L、通气量100 mL／min、体系pH值是7时,50mg/L的酸性红B经3 h光催化降解,其降解率可达92．9％：与纯TiO2相比,La^3＋／]TiO2光催化剂显示出良好的太阳光催化活性：     

TiO2/ACF复合滤料光降解甲醛的实验研究

 以钛酸丁酯[Ti(OBu)4]为原料,用溶胶凝胶法制备纳米TiO₂溶胶,采用浸渍法将溶胶整理到活性炭纤维(ACF)滤料上,并对ACF滤料原样、整理样光催化氧化甲醛气体的性能进行静态、动态对比实验。静态实验中,弱光源条件下ACF滤料原样、整理样的甲醛净化率分别为33.3%、39.6%,在强光源条件下分别为38.6%,49.2%;动态实验中,弱光源条件下ACF滤料原样、整理样的甲醛净化率分别为69.9%、77.1%,在强光源条件下分别为77.1%,85.5%。证明纳米TiO₂在强光源和弱光源条件下均可以光降解甲醛。     

负载TiO2织物的制备及其太阳光催化活性研究

用涂层法制备了具有光催化性能的负载TiO2织物。利用太阳光为光源,以甲基橙为研究对象,考察了负载TiO2织物的光催化特性,研究了光照时间、光催化剂投放量对甲基橙降解的影响,讨论了该功能型织物的持久效力问题。研究结果表明:制备的负载TiO2织物有较高的光催化降解能力,且性能持久。     

TiO2光催化技术处理制浆造纸废水的试验研究

探讨了TiO2光催化技术处理纸厂废水时的影响因素,并由此确定出较优的反应条件为催化剂选择20%金红石和80%锐钛矿组成的混晶型TiO2,催化剂用量1g/L,曝气采用纯氧曝气,O2流速为0.5L/min。在此条件下,研究了制浆造纸废水TiO2光催化降解效果;结果表明TMP废水、纸厂废水等低浓低污染物废水比KP废水更适宜于TiO2光催化降解处理。     

食品添加剂二氧化钛和纳米二氧化钛对大鼠肝脏DNA损伤作用的评价

目的 利用哺乳动物体内碱性彗星试验,评价食品添加剂二氧化钛和纳米二氧化钛对大鼠肝脏细胞DNA的损伤作用。方法 依据哺乳动物体内碱性彗星试验指南（OECD TG489）,将雄性SD大鼠随机分成9组,每组5只。食品添加剂二氧化钛设1 000、500、250 mg/kg·BW 3个剂量组,阴性对照为纯水;纳米二氧化钛设500、150、50 mg/kg·BW 3个剂量组,阴性对照为0.8%吐温+3%FBS。通过灌胃方式给予,每日1次,共15 d;同时设置阳性对照组,阳性物甲基磺酸乙酯（EMS）仅在第14、15天每日灌胃一次给予,剂量为200 mg/kg·BW·d。末次灌胃6 h后,麻醉条件下取大鼠肝脏,制备成单细胞悬液后涂片,经裂解、解旋、电泳、染色等步骤,进行彗星图像分析。结果 食品添加剂二氧化钛和纳米二氧化钛各剂量组大鼠肝脏细胞的尾部DNA含量百分比与相应阴性对照组相比均无显著性差异（P>0.05）,而EMS组大鼠肝脏细胞的尾部DNA含量百分比与阴性对照组比较均具有显著差异（P<0.01）。结论 在本实验条件下,食品添加剂二氧化钛和纳米二氧化钛均未诱导大鼠肝脏细胞的DNA损伤。     

Use of titanium dioxide (TiO2) photocatalysts as alternative means for Listeria monocytogenes biofilm disinfection in food processing

The aim of this work was to study the photocatalytic activity of titanium dioxide (TiO₂) against Listeria monocytogenes bacterial biofilm. Different TiO₂ nanostructured thin films were deposited on surfaces such as stainless steel and glass using the doctor-blade technique. All the surfaces were placed in test tubes containing Brain Heart (BH) broth and inoculated with L. monocytogenes. Test tubes were then incubated for 10 days at 16 °C in order to allow biofilm development. After biofilm formation, the surfaces were illuminated by ultraviolet A light (UVA; wavelength of 315-400 nm). The quantification of biofilms was performed using the bead vortexing method, followed by agar plating and/or by conductance measurements (via the metabolic activity of biofilm cells). The presence of the TiO₂ nanoparticles resulted in a fastest log-reduction of bacterial biofilm compared to the control test. The biofilm of L. monocytogenes for the glass nanoparticle 1 (glass surface modified by 16% w/v TiO₂) was found to have decreased by 3 log CFU/cm² after 90 min irradiation by UVA. The use of TiO₂ nanostructured photocatalysts as alternative means of disinfecting contaminated surfaces presents an intriguing case, which by further development may provide potent disinfecting solutions. Surface modification using nanostructured titania and UV irradiation is an innovative combination to enhance food safety and economizing time and money.     

PET非织造基溅射TiO_2/Nd/TiO_2及其抗菌性

利用磁控溅射技术,在室温条件下将纳米稀土Nd及光催化型抗菌材料TiO2以TiO2/Nd/TiO2方式沉积在PET非织造布表面,以制备纳米结构稀土激活TiO2复合抗菌材料。由于宽化了纳米TiO2的吸收光谱,制备的材料在可见光照射的情况下具有较好的抗菌效果。通过正交试验,获得最佳的溅射制备条件,即TiO2溅射功率75 W,Nd溅射功率40 W,Ar气体流量15 mL/min,反应压强1 Pa,所制备的复合抗菌薄膜抗菌效果最好。     

Enhanced sonocatalytic degradation of azo dyes by Au/TiO2

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.     

氧化石墨烯协同TiO2/SiO2改性涤/棉织物的抗菌持久性与服用性

为解决单一TiO₂改性涤/棉织物在可见光下光催化效率低、抗菌活性弱且不持久等问题,采用氧化石墨烯协同TiO₂/SiO₂掺杂复合改性涤/棉织物。利用场发射显微镜、明暗条件下的抗菌性实验、纺织品色牢度实验、拉伸断裂测试和弯曲性能测试等手段对复合改性前后织物的微观形貌、抗菌性及抗菌持久性、服用性能等进行分析评价。结果表明:在可见光下,TiO₂/SiO₂/氧化石墨烯复合改性织物表面纳米粒子涂覆均匀,抑菌率在99%以上,复合改性织物在15次水洗后其抑菌率仍保持为98.5%;虽然改性后织物的拉伸断裂性能、透气性能、手感等都有一定程度的损失,但损失影响不大。     

Toxicological sanitary characterization of titanium dioxide nanoparticles introduced in gastrointestinal tract of rats. Communication 2. Intestinal microbiocenosis condition and allergic sensitivity

Intestinal microbiocenosis condition, cytokine IL-6, IL-10 and TNF-alpha levels and allergic sensitivity in experimental systemic anaphylaxis test were studied in rats that received intragastrically nanoparticles of titanium dioxide. The results obtained were discussed from the standpoint of possible health risks related to nanodimensional titanium dioxide exposure.     

纳米SnO2/TiO2/MMT制备及其光催化性能

比较不同制备方法制得的复合催化剂,由超临界干燥法制备的光催化剂具有粒径小,分散性好,光催化活性高等特点.以TiCl4为原料,采用溶胶凝胶法结合超临界流体干燥法(SCFD)制备了纳米级SnO2TiO2/MMT(蒙脱土)复合光催化剂.采用XRD和TEM对样品进行了表征.结果表明:TiO2以锐钛矿型形式存在,催化剂粒径在13～20 nm.以活性红X-3B溶液、活性橙K-NG和活性紫X-2R为反应模型,对所得催化剂的催化活性进行了评价,降解率分别达到99.9％、99.6％和99.5％,化剂循环利用时仍具有较高的催化活性.     

活性炭吸附结合TiO2光催化分离纯化杨木预水解液中的木糖

利用活性炭吸附和TiO₂光催化降解脱除杨木预水解液中的溶解木素,探讨了不同活性炭类型（木质基磷酸活化活性炭、食品质303活性炭、煤质活性炭）、活性炭用量、吸附时间、光催化时间、TiO₂用量对预水解液中木素、总木糖、糠醛、羟甲基糠醛（5-HMF）以及乙酸等有机组分含量的影响,优化确定了活性炭吸附和TiO₂光催化降解条件。研究结果表明,木质基磷酸活化活性炭对木素的吸附脱除效果最好,在活性炭用量为1.0%和吸附时间为10 min时,总木糖得率为93.1%,木素、糠醛、5-HMF、乙酸脱除率分别为75.1%、29.3%、22.4%、3.5%。单一TiO₂光催化处理,在TiO₂用量1.0%和光催化时间10 h条件下,总木糖得率为89.0%,木素、糠醛、5-HMF、乙酸脱除率分别为40.2%、24.2%、32.1%、3.1%。活性炭协同TiO₂光催化处理预水解液的较优工艺条件为：木质基磷酸活化活性炭用量1.0%、光催化时间6 h和TiO₂用量0.1%~0.5%,此条件下预水解液中木素的脱除率为84.4%~86.7%,总木糖得率为88.2%~89.8%,糠醛脱除率为53.8%~65.1%,5-HMF脱除率为48.6%~51.7%,乙酸含量变化不明显 。     

TiSiW12O40/TiO2催化合成抗氧化剂没食子酸异戊酯的研究

以TiSiW12O40/TiO2作为催化剂,用没食子酸与异戊醇直接酯化合成了食品抗氧化剂没食子酸异戊酯。通过正交试验研究了影响没食子酸异戊酯收率的主要因素,得到了最佳实验条件为:醇酸物质的量比为10∶1,催化剂用量为反应物总质量的3%,反应时间为3h,没食子酸异戊酯的收率可达95.6%,考察了该催化剂的重复使用性。抗氧化性能测试结果表明,没食子酸异戊酯具有优良的抗氧化性能。