纳米二氧化钛对隔离子的吸附研究

研究了纳米二氧化钛吸附溶液中镉离子的有效方法和途径.采用双硫腙直接比色法测定镉离子浓度,详细研究了纳米二氧化钛吸附镉离子过程中的影响因素.通过实验,确定了吸附的最佳条件,进一步研究了吸附镉离子后二氧化钛的洗脱以及设想模拟实体水样中痕量镉离子的检测.样品体系在pH=10,震荡时间9 min以上的条件下,纳米二氧化钛对镉离子的吸附率可达99 %.吸附在纳米二氧化钛上的镉离子可以用0.1 mol/L的硝酸进行洗脱,洗脱率在95 %以上.     

纳米TiO2及其复合材料的抗菌性能研究

TiO2是一种宽禁带N型半导体纳米材料,也是具有光催化能力的光催化材料。本文概述了纳米TiO2的制备方法,分析了纳米TiO2的抗菌性及抗菌机理,并且综述了纳米TiO2掺杂阴、阳金属离子和复合半导体等后复合材料的抗菌性及抗菌机理,文末进一步思考展望了纳米TiO2在其他功能材料领域有待解决的研究问题。     

纳米二氧化钛光催化降解甲醛、氨气的研究

以自制纳米二氧化钛为主体,高铝酸盐为载体制备了复合光催化材料。以甲醛、氨气模拟实验样品,考察了材料的组成比例、吸附作用、光照条件对甲醛、氨气降解效率的影响。结果表明:高铝酸盐与自制纳米二氧化钛按8∶2成膜制备的复合材料,在光催化降解甲醛、氨气的实验中,效果明显;且光催化降解作用优于吸附的降解作用;当催化材料距光源较远时,引入导光光纤可明显提高光催化材料的催化效率。     

多重乳液法制备空腔状纳米二氧化钛

采用多重乳液法制备纳米二氧化钛,研究了运用多重乳液法制备二氧化钛的现实意义。将钛酸四正丁酯以一定比例溶于外油相中,再加入一个水包油的微乳液内相,生成O／W／O型多重乳液体系,钛盐在水相中水解形成空腔状的纳米二氧化钛颗粒,用X光衍射仪对其进行了表征,得知产物为锐钛型纳米TiO2,并进行了紫外一可见吸收分析。结果表明,材料吸收带有一定程度的蓝移,即表明纳米颗粒变小,纳米尺寸效应明显。     

纳米TiO_2光触媒的制备及应用研究

以尿素为均匀沉淀剂、硫酸氧钛为原料制备粒径可控、分散性良好的纳米二氧化钛粉体。系统地研究了制备条件对粒径大小、粒子形貌的影响,探讨了均匀沉淀法形成纳米二氧化钛粉体的机理、晶体成长和晶型转化动力学以及光催化性能,并列举了作为光触媒的应用实例。     

纳米TiO2薄膜制备方法的研究进展

纳米二氧化钛以其优异的化学、物理性能受到关注。薄膜是纳米二氧化钛的重要形式,制备纳米二氧化钛薄膜具有重要意义和很好的应用前景。依据制备工艺中温度的要求,对制备纳米二氧化钛薄膜的方法进行了概述,高温制备的工艺主要有溶胶-凝胶法、水热法、气相沉积法,低温制备工艺主要有电泳沉积法、紫外光照射法、电化学制备法、模板自组装制备法。     

纳米二氧化钛对污水中化学需氧量的影响

本文以均相沉淀法制得的纳米Ti O2为光降解活性剂,采用酸性高锰酸钾法研究了纳米Ti O2对污水化学需氧量(COD)的影响。结果表明:纳米Ti O2的加入量为2 mg/L(污水)、降解时间2 h时,纳米Ti O2对污水COD值的影响最显著。     

改性纳米TiO2光催化剂的研究进展

目前,国内外纳米TiO2光催化剂的改性技术日益完善,且日趋多样化。文章简述了复合半导体、TiO2光敏化、表面超强酸化、TiO2光催剂的固定技术、等离子体改性、改变TiO2的介电性能等改性技术方法的基本工作原理及所需要注意的问题,并且针对各种改性方法列举了国内外应用的具体实例,提出光催化剂的改性是提高光催化反应效率的重点所在。     

纳米二氧化钛的制备及对金属离子吸附研究进展

综述了纳米二氧化钛的制备技术。介绍了各种制备技术的基本原理,将各种制备方法制备的纳米二氧化钛的性能进行了比较,并指出了各种制备技术的特点。对纳米二氧化钛对金属离子吸附的研究进展进行了分析。     

聚酰亚胺/纳米钛系粒子杂化膜制备与性能

采用原位聚合法和流延成膜法制备了系列纳米钛系粒子含量的聚酰亚胺(PI)/TiO2和PI/BaTiO3杂化膜,以γ-巯丙基三甲氧基硅烷偶联剂(KH590)对纳米钛系粒子进行表面处理以提高有机-无机相之间的界面相容性,通过傅里叶变换红外光谱、广角X射线衍射对杂化膜的结构进行研究,同时分析了TiO2和BaTiO3对杂化膜热性...     

双元素掺杂改性二氧化钛的研究进展

纳米TiO2作为一种光催化材料,在环境保护、光能转换、医药行业、工业催化等领域有着极为广泛的用途.较低的光量子效率以及短波长高能量的激发源是限制TiO2使用范围的主要原因,进行掺杂改性以实现可见光响应和提高量子效率是提高光催化剂活性的重要方法,但是单组分的掺杂不能同时提高这两种因素,因此多组分掺杂变的重要.本文综述了近几年来利用两种元素协同掺杂来改善TiO2光催化活性方面所取得的进展.     

Preparation of Nano-titanium Dioxide in Propane/Air Diffusion Flame

Titanium dioxide (TiO2) nanoparticles were synthesized by the oxidation of titanium tetrachloride (TiCl4), in propane/air diffusion flame. The propane/air diffusion flame is generated using a multi-port diffusion type burner composed of 4 concentric tubes. Flow rates of TiCl4 and combustion gases such as air, industrial propane and carrier gas were chosen as key experimental variables for the control of the particle size and morphology. Effects of propane/air mole ratio and precursor flow rate on particle size, morphology, structure and carbon dots of titanium dioxide particles were studied.     

玻璃纤维负载纳米TiO2的制备及光催化性能

采用浸渍-提拉法在玻璃纤维(GF)表面负载纳米TiO2,制备TiO2/GF复合光催化剂.通过X射线衍射(XRD)、热重-差热分析(TG-DSC)、扫描电镜(SEM)及能谱元素分析(EDS)对TiO2/GF复合光催化剂的结构进行了表征.结果表明,经550 ℃以下热处理,TiO2的晶型为锐钛矿相,随着热处理温度的升高,TiO2的晶型逐渐转化为金红石相.以亚甲基蓝的光催化降解为探针反应,评价TiO2/GF复合材料的光催化活性.复合材料的光催化降解活性与P25相当,且经多次使用后,复合光催化剂对亚甲基蓝的降解率仍保持在80%以上.     

溶胶-凝胶法制备纳米二氧化钛的工艺条件优化

以钛酸丁酯为原料,采用溶胶-凝胶法制备纳米二氧化钛,探讨了钛酸丁酯的用量、钛酸丁酯与醋酸的体积比、钛酸丁酯与乙醇的体积比、煅烧温度、煅烧时间等对溶胶-凝胶法的影响,得出了制备纳米二氧化钛的最佳工艺条件。结果表明,制备二氧化钛的最佳工艺条件为:钛酸丁酯的用量为10mL,钛酸丁酯与醋酸的体积比为2∶1,钛酸丁酯与乙醇体积比为1∶3,煅烧温度为500℃,煅烧时间为2h。对最佳工艺条件下制备的二氧化钛进行XRD表征,二氧化钛的白度平均值为92.2;粒径平均值为18.5nm,粒径小于20nm。     

Comparative antioxidant potency of 2,4,5-trihydroxyphenones

Conclusions On the basis of AOM tests run to date it appears that 2,4,5-trihydroxyphenones are quite potent antioxidants for many applications. Some of the lower members of the series, such as 2,4,5-trihydroxybutyrophenone, are outstandingly effective in lard, paraffin wax, mineral oil, and peanut oil. In other media, such as cottonseed oil, corn oil, castor oil, sesame oil, and tallows, they are less effective but still fairly active. In greases, palm oil, and sperm oil, they are only moderately effective. Over-all the 2,4,5-trihydroxyphenones compare quite favorably with current commercial products. It would appear that as more testing is done, more applications for these compounds may be found. Subacute toxicity studies made with 2,4,5-trihydroxyacetophenone and 2,4,5-trihydroxybutyrophenone indicate that they are of a low order of toxicity. Long-term feeding tests on rats and dogs are underway with the butyrophenone, and after four months there are no apparent ill effects.     

Increasing the potency of a cytotoxin with an arginine graft

Variants and homologs of bovine pancreatic ribonuclease (RNase A) can exhibit cytotoxic activity. This toxicity relies on cellular internalization of the enzyme. Residues Glu49 and Asp53 form an anionic patch on the surface of RNase A. We find that replacing these two residues with arginine does not affect catalytic activity or affinity for the cytosolic ribonuclease inhibitor (RI) protein. This 'arginine graft' does, however, increase toxicity towards human cancer cells. Appending a nonaarginine domain to this cationic variant results in an additional increase in cytotoxicity, providing one of the most cytotoxic known variants of RNase A. These findings correlate the potency of a ribonuclease with its deliverance of ribonucleolytic activity to the cytosol, and indicate a rational means to enhance the efficacy of ribonucleases and other cytotoxic proteins.     

Redox sensitization in the photochromic polymers of the thionine series

The incorporation of electron-donating components such as mono-, di-, and triethanolamines into the thionine photoredox system was tried (1) by copolymer preparations containing the acrylamidomethylthionines and triethanolamine monoacrylic ester as components, (2) by the reaction of triethanolamine and thionines with the N-hydroxy-methyl group in polymer in an acid medium, and (3) by the reaction of mono- or diethanolamine and thionines with the N-hydroxymethyl group. The photochromic behavior incorporated into the polymer chain are as effective as their monomeric equivalents, to the extent that the sensitivity is among the highest so far investigated.     

Absorption of nitrogen dioxide and sulfur dioxide in methanol

Gas-liquid chromatography was employed to determine the activity coefficients of NO₂ and SO₂ at infinite dilution in methanol. The infinite dilution activity coefficients at 301.2 K were found to be 15.5 ± 0.1 and 0.491 ± 0.055 for the systems NO₂-methanol and SO₂-methanol, respectively. These values were subsequently used along with the single parameter Wilson equation to predict vapor-liquid equilibrium data for the systems NO₂-N₂-methanol and SO₂-N₂-methanol.     

提高二氧化硫脲在Ni^2＋ -NH3反应体系中利用率研究

研究了温度、酸度在二氧化硫脲与Ni^2＋ -NH3反应体系中的影响,得出升高温度、增加pH值均有利于提高二氧化硫脲的利用率,降低生产成本;同时探讨了该体系反应机理,指出体系同时存在相互竞争的单电子反应和双电子反应,改变温度和酸度影响了反应的历程。