TiO2纳米颗粒光催化降解甲醛的影响因素

采用溶胶-凝胶法合成TiO2纳米颗粒,TEM结果表明,颗粒的平均粒径为20nm,电子衍射环图结果表明,TiO2颗粒晶体结构为锐钛矿型;在光催化反应系统中对TiO2颗粒制备的薄膜进行了甲醛的光催化降解实验,考察了TiO2颗粒制备的薄膜的层数、溶胶体系pH值、活化温度及活化时间等条件对TiO2薄膜光催化降解甲醛性能的影响.实验结果表明,溶胶-凝胶法的制备工艺条件对TiO2薄膜的光催化活性有较大影响,活化的温度和活化的时间影响最大,其次是溶胶体系的pH值,当pH=2,活化温度为500℃,活化时间5h,制成的TiO2薄膜光催化降解甲醛的降解率可达60%以上.     

低温制备纳米TiO2溶胶整理棉织物对染料的降解

 在室温条件下使钛酸丁酯水解制备纳米TiO2溶胶,然后利用后整理技术将其负载于棉纤维表面得到纳米TiO2整理棉织物。在对纳米TiO2溶胶及其整理棉织物表征的基础上,将纳米TiO2整理棉织物作为光催化剂应用于有机染料罗丹明B的降解反应中,重点考察了水与钛酸丁酯的物质的量比、陈化时间以及纳米TiO2整理棉织物增重率对脱色率的影响,并研究了纳米TiO2整理棉织物的重复利用性和罗丹明B的降解反应动力学。结果表明,在纳米TiO2溶胶的制备中,水与钛酸丁酯物质的量比的增加能形成粒径小而均匀的溶胶。通过浸烘整理工艺能使纳米TiO2溶胶在棉纤维表面形成锐钛型纳米TiO2结晶薄膜。当纳米TiO2整理棉织物作为光催化剂时,罗丹明B的脱色率随增重率的增加而提高,并且水与钛酸丁酯物质的量比的增加和陈化时间的延长都能够明显改善其光催化活性。纳米TiO2整理棉织物作为光催化剂可以重复使用,并且罗丹明B在纳米TiO2整理棉织物存在下的光催化降解反应符合假一级动力学反应模型。     

纳米TiO_2环境净化整理剂的制备及应用性能

采用低温制备技术合成纳米TiO2水溶胶,并采用浸渍工艺使纳米TiO2负载在棉织物表面形成薄膜,然后用于水中染料和空气中甲醛的催化降解反应中。同时,将纳米TiO2水溶胶与有机硅复配制成纳米TiO2环境净化整理剂,探讨了有机硅乳液对纳米TiO2水溶胶净化性能的影响。结果表明,在光辐射的条件下纳米TiO2粒子能够使不同结构染料分子发生氧化降解反应,其对酸性红88的催化降解效果更好,并能用于高浓度染料废水的处理;紫外光辐射下,纳米TiO2对空气中甲醛具有更好的催化降解效果;有机硅乳液对纳米TiO2净化性能的影响很小,但能改善纳米TiO2在纤维表面的固着和织物的手感。     

织物负载TiO_2光催化剂的制备及活性红MS光催化动力学

实验采用溶胶一凝胶法制备纳米TiO2溶胶,棉织物经过浸渍TiO2溶胶-烘干-焙烘法处理,在织物表面低温制备TiO2薄膜.采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)等方法对样品结构和形貌进行分析和表征.在紫外灯照射下,以活性红MS为降解物,研究了制备条件包括TiO2浓度、TiO2溶胶pH值、焙烘温度和焙烘时间对薄膜光催化性能的影响.结果表明在低温下制备的TiO2主要是锐钛矿型,并且薄膜的光催化活性与处理工艺有关.在TiO2浓度为0.423 mol/L.TiO2溶胶pH值为1.67、焙烘温度为80℃、焙烘时间为2 min的条件下,活性红MS的光催化降解速率常数最大,拟合紫外光下光催化薄膜降解活性红MS为一级反应.     

聚丙烯酸酯/纳米TiO_2复合乳液的制备及应用

采用溶胶-凝胶法制备了纳米二氧化钛(TiO2)溶胶,分别考察了溶剂种类和溶剂用量对纳米二氧化钛溶胶的影响。将制得的溶胶与纯聚丙烯酸酯乳液共混,制备聚丙烯酸酯/纳米TiO2复合乳液,并对复合乳液涂膜的力学性能和耐水性能进行检测。最后将复合乳液应用于皮革涂饰,对涂饰后革样的应用性能进行测试。试验结果表明:采用二乙醇胺或三乙醇胺为溶剂制得的TiO2溶胶较为稳定,随着二乙醇胺或三乙醇胺用量的增加,纳米TiO2溶胶的稳定性变好,同时溶胶与乳液的相容性较好。纳米TiO2溶胶的引入使涂饰后革样的耐水性提高17.06%,透水汽性增加23.87%。     

纳米TiO2溶胶在负离子整理中的应用

采用溶胶-凝胶法制备了纳米TiO2溶胶,并对棉织物进行负离子整理.探讨了不同因素对溶胶性能以及棉织物负离子发生量的影响,确定的优化工艺为:钛酸丁酯:二乙醇胺:乙醇:水为1:1:30:2.4(物质的量比),整理后棉织物的负离子发生量为2 380个/cm3,且织物白度变化不大.     

棉织物的Ag负载纳米TiO2溶胶功能整理

采用溶胶-凝胶法在低温条件下制备了Ag负载纳米TiO2溶胶,并将其应用于棉织物的功能性整理,利用XRD、TEM、XPS、SEM等手段进行表征,测定了织物的光催化性能、抗菌性能和抗紫外线性能。结果表明,通过加入络合剂和还原剂,可在低温条件下制备Ag负载纳米TiO2溶胶,且所制备的纳米TiO2为锐钛矿型。棉织物经Ag负载纳米TiO2溶胶整理后,光催化性能有极大提升,当沉积量为3%时,其光催化性能最佳;同时,整理织物表现出优异的抗菌性能和抗紫外线性能。     

纳米TiO2/柞蚕丝素对棉织物的功能整理

用溶胶-凝胶法制备纳米TiO2溶胶,并以该纳米TiO2和柞蚕丝素等的混合溶液对棉织物进行功能整理.用激光粒径仪表征了纳米TiO2溶胶及其柞蚕丝素整理液的粒径分布,测试了整理前后棉织物的抗紫外线性能、润湿性能(接触角)、悬垂风格、白度及撕破强力.结果表明:制得的纳米TiO2溶胶及其柞蚕丝素整理液中纳米粒子的平均粒径分别为13.31 nm和77.90 nm,经纳米TiO2/柞蚕丝素整理的棉织物抗紫外线性能优良,UPF值大幅增加,棉织物的柔软度、悬垂风格及吸湿性得到改善,撕破强力及白度稍有下降.     

不同纳米TiO2负载棉织物在染料降解反应中的比较研究

将低温制备的两种纳米TiO2水溶胶和两种商品化纳米TiO2粉体（5 nm和30 nm）通过浸轧工艺负载于棉织物表面形成纳米TiO2负载棉织物。在经过XRD和SEM表征后,四种纳米TiO2负载棉织物被用于纺织染料酸性红88的降解反应中,考察和比较了它们的光催化降解性能。结果表明,四种纳米TiO2都属于锐钛型,但是水溶胶中的纳米TiO2结晶并不完善。两种纳米TiO2水溶胶和5 nm纳米TiO2粉体在纤维表面所形成薄膜具有相似的形貌,但是与30 nm纳米TiO2粉体所形成薄膜形貌明显不同。两种纳米TiO2水溶胶和5 nm纳米TiO2粉体负载棉织物在酸性和中性介质中的催化降解性能高于30 nm纳米TiO2粉体负载棉织物,但是在碱性介质中两种纳米TiO2粉体负载棉织物的催化降解性能却高于两种纳米TiO2水溶胶负载棉织物。在可见光辐射条件下30 nm纳米TiO2粉体负载棉织物 的催化降解性能显著低于其它三种纳米TiO2负载棉织物,而氯化钠或十二烷基苯磺酸钠存在时纳米TiO2粉体负载棉织物却显示出比纳米TiO2水溶胶负载棉织物更好的催化降解性能。     

织物负载TiO2光催化剂的制备及活性红MS光催化动力学

实验采用溶胶-凝胶法制备纳米TiO2溶胶,棉织物经过浸渍TiO2溶胶-烘干-焙烘法处理,在织物表面低温制备TiO2薄膜。采用X射线衍射仪（XRD）、扫描电子显微镜（SEM）等方法对样品结构和形貌进行分析和表征。在紫外灯照射下,以活性红MS为降解物,研究了制备条件包括TiO2浓度、TiO2溶胶pH值、焙烘温度和焙烘时间对薄膜光催化性能的影响。结果表明在低温下制备的TiO2主要是锐钛矿型,并且薄膜的光催化活性与处理工艺有关。在TiO2浓度为0．423mol／L、TiO2溶胶pH值为1．67、焙烘温度为80℃、焙烘时间为2min的条件下,活性红MS的光催化降解速率常数最大,拟合紫外光下光催化薄膜降解活性红MS为一级反应。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the