氮掺杂二氧化钛光催化降解亚甲基蓝的动力学研究

以分析MB初始浓度,催化剂用量以及pH值对光催化速率的影响为基础,研究了氮掺杂二氧化钛催化亚甲基蓝动力学行为;结果表明催化反应符合Langmuir等温吸附规律,pH值为3时降解速率达到最大值,并且光催化速率的变化随着催化剂用量呈现饱和现象.     

铁掺杂介孔二氧化钛的制备及其光催化性能

采用溶胶-凝胶法,以价廉的硫酸钛和硝酸铁为原料制备了不同含量的掺铁介孔二氧化钛。采用 X 射线衍射、扫描电子显微镜、热重-差示扫描量热分析、N2吸附-脱附、X 射线光电子能谱、紫外-可见漫反射对样品进行表征。以亚甲基蓝（MB）为目标降解物,对催化剂的光催化性能进行了研究。结果表明：铁以 Fe3＋、Fe2＋取代 Ti4＋进入 TiO2的晶格。适量掺铁使 TiO2的吸收带边发生红移,有利于提高样品光催化性能和保持良好的重复套用活性。最佳掺铁量（摩尔比）为 n（Fe）/n（Ti） = 2%,对应样品颗粒大小为 0.1～0.2 μm,比表面积为 117.6 m2/g,孔容积为 0.434 cm3/g,平均孔径为13 nm。重复套用 4 次后,240 min 内对 MB 的总脱色率仍然达 89.0%,降解率达 70.7%.     

Ys＋掺杂Ti02光催化降解亚甲基蓝

以Y3＋掺杂二氧化钛为光催化剂,以亚甲基蓝为模拟印染废水进行光催化降解实验,考察了催化剂用量、溶液初始pH值、溶液初始浓度、反应时问等因素对降解反应的影响,结果表明：当催化剂的用量为1。5g/L,亚甲基蓝洛液pH值为9．0、初始浓度为20mg／L,反应60rain后,其降解效果最佳。     

二氧化钛纳米管阵列制备和光催化降解亚甲基蓝

采用电化学阳极氧化的方法,以氟化铵水溶液为电解液,在纯钛表面制备了TiO2纳米管阵列。以亚甲基蓝为模拟污染物,考察了TiO2纳米管阵列光催化降解效果。结果表明,TiO2纳米管阵列催化降解效果要好于TiO2薄膜电极,当降解时间为1h、2h、3h和4h时,降解率分别为57.84%、86.44%、93.66%和95.72%;而TiO2薄膜电极的降解率分别为50.18%、76.27%、87.31%和91.53%。在此基础上,考察了阳极氧化电压、氧化时间和焙烧温度对阳极氧化过程的影响规律。结果表明,阳极氧化电压在25V,氧化时间在1h,焙烧温度在500℃时所制备的TiO2纳米管阵列的光催化降解性能最好。     

镧掺杂对TiO2光催化降解亚甲基蓝溶液性能影响

采用溶胶-凝胶法制备了La2O3/TiO2光催化剂,以亚甲基蓝为目标降解物,研究了催化剂的组成、制备条件对光催化性能的影响.结果表明,经600℃热处理得到的掺杂质量分数为0.1%,La2O3/TiO2光催化剂对亚甲基蓝具有较好的降解活性.探讨了影响光催化反应的各种因素,发现最佳的催化剂浓度为3.0～5.0 g·L-1,反应时间和光照强度增加都能明显提高La2O3/TiO2的催化效率.     

多级孔Fe/ZSM-5的制备及其亚甲基蓝降解性能研究

通过常规方法合成微孔ZSM-5并对其进行NaOH处理,KF体系下采用三甲氧基[3-(苯氨基)丙基]硅烷(PHAPTMS)为介孔模板剂分别制备4种具有不同孔道结构的ZSM-5.通过X射线衍射、透射电子显微镜、氩气物理吸附等表征手段证明所合成的4种ZSM-5均具有MFI拓扑结构且结晶良好,而加入PHAPTMS得到的样品的介...     

Cu_2O掺杂TiO_2光催化降解亚甲基蓝的研究

以钛酸四丁酯和乙酸铜为原料,柠檬酸和葡萄糖作还原剂,采用水解法制备了Cu_2O/TiO_2复合光催化剂,并通过XRD和SEM表征手段进行了表征。以Cu_2O/TiO_2为光催化剂,考察了反应时间、初始浓度、催化剂用量、起始pH和温度等因素对光催化降解亚甲基蓝脱色率的影响。结果表明,在高压汞灯照射下,以0.01 g Cu_2O/TiO_2为光催化剂,以100 mL 10 mg/L亚甲基蓝溶液为模拟废水,pH为7.0,25℃下光催化反应60 min,亚甲基蓝脱色率可以达到94.38%,其脱色动力学反应为准一级过程。     

二氧化钛纳米管对亚甲基蓝的吸附

采用水热法制备了TiO2纳米管,借助X射线衍射(XRD)、透射电镜(TEM)对产物进行了表征。以亚甲基蓝溶液为体系,考察了TiO2纳米管的吸附性能。结果表明:TiO2纳米管为锐钛矿相,管径小、管形均匀。黑暗条件下TiO2纳米管对亚甲基蓝具有优异的吸附活性,30 min可达到吸附平衡,吸附量达38.3mg/g,最佳吸附质量比为w(MB):w(TiO2)≈0.075。     

磁悬浮型硫氮共掺杂二氧化钛光催化剂降解甲基橙的研究

以粉煤灰浮选出的磁性空心微珠为载体,以钛酸四丁酯为原料,以硫脲为添加剂,采用溶胶-凝胶-低温烧结法制备了可磁性分离回收的悬浮型硫氮共掺杂Ti O2复合光催化剂,研究了催化剂对甲基橙的光催化活性。结果显示,在可见光为光源的条件下,催化剂对甲基橙具有良好的光降解功效,在p H=6.3、催化剂用量为2 g/L、甲基橙初始质量浓度为10 mg/L的条件下,光照1.5 h后,降解率达到93%。催化剂可通过磁铁进行液固分离回收,干燥活化后对甲基橙的降解率仍在80%以上。     

磁悬浮型硫氮共掺杂二氧化钛光催化剂降解甲基橙的研究

以粉煤灰浮选出的磁性空心微珠为载体,以钛酸四丁酯为原料,以硫脲为添加剂,采用溶胶-凝胶-低温烧结法制备了可磁性分离回收的悬浮型硫氮共掺杂Ti O2复合光催化剂,研究了催化剂对甲基橙的光催化活性。结果显示,在可见光为光源的条件下,催化剂对甲基橙具有良好的光降解功效,在p H=6.3、催化剂用量为2 g/L、甲基橙初始质量浓度为10 mg/L的条件下,光照1.5 h后,降解率达到93%。催化剂可通过磁铁进行液固分离回收,干燥活化后对甲基橙的降解率仍在80%以上。     

Designing and Preparing a Thin-Film Photocatalyst from Titanium Dioxide Nanotubes Codoped with Nitrogen and Fluorine

Theoretical Foundations of Chemical Engineering - Thin-film nanostructured coatings have been produced electrolytically from TiO2 codoped with nitrogen and fluorine. The resulting films consist of...     

Designed Highly Effective Photocatalyst of Anatase TiO2 Codoped with Nitrogen and Vanadium Under Visible-light Irradiation Using First-principles

Fe/ZSM-5 and Cu-ZSM-5 were investigated for selective catalytic reduction of NO_x with ammonia. The Fe/ZSM-5 catalyst showed over 90% NO conversion from 350 to 500 °C and Cu-ZSM-5 showed over 90% NO conversion from 250 to 350 °C. After pretreatment in 10% H₂O at 700 °C, the Fe/ZSM-5 still exhibited high activities and stability. On the basis of the experiments, Fe/ZSM-5 and Cu-ZSM-5 seem to be promising candidates for diesel-engine NO_x emission control.     

尿素为氮源制备氮掺杂二氧化钛光催化剂

以Ti(SO4)2为前驱物,尿素为沉淀剂和掺杂剂,采用水热法结合固相反应法制得了锐钛矿相掺氮纳米TiO2纳米粉体。采用XRD对制备的掺氮氧化钛结构进行了表征,以亚甲基蓝为模拟污染物,考察了不同煅烧温度制备的光催化剂在可见光照射下的光催化性能。结果表明,煅烧温度高于160℃时氮可掺进TiO2晶体中,且温度越高,掺氮量越高;煅烧温度为200℃时,氮掺杂TiO2粉体可见光催化活性最强,在波长不低于400nm的可见光作用下,对亚甲基蓝的4h降解率达62.5%。     

Preparation of Self-Standing, Submillimeter-Thick Porous Titania Films with Anatase Nanocrystallites Using Evaporation-Induced Self-Assembly

Self-standing transparent submillimeter-thick (∼0.34 mm) mesoporous titania films were prepared using the evaporation-induced self-assembly (EISA) of a triblock copolymer template and titanium tetraethoxide. Performing EISA at low temperature and low humidity improved the transparency and continuity of the films. As synthesized films had a well-defined hexagonal mesostructure and the existence of both amorphous titania and anatase nanocrystallites (2 nm) was confirmed. The films that were calcined at 400°C were composed of anatase nanocrystallites (14–16 nm) and had a BET surface area of 90 m² g⁻¹ with 13-nm pores. The films were characterized using XRD, FE-SEM, TEM, and N² adsorption–desorption measurements. An erratum to this article can be found at     

Electrical Properties of Porous Titania Ceramic Humidity Sensors

Ceramic humidity sensors made with pure TiO₂ powder as the starting material are investigated. The sensor can be reversibly operated without repeated high-temperature thermal desorption, and the conductance versus relative humidity (rh) sensitivity of the sensor is more than 4 orders of magnitude in the range ∼15% to 95% rh at 400 Hz and 25°C. The sensor can be polarized similar to electrolytes in the charging process, and the degree of polarization is enhanced with increasing rh. The conduction carriers of the sensor in the humid atmosphere are ions and electrons, and ions are the dominant conduction carrier. The relative dielectric dispersion k'(ω) is almost proportional to ω^−1.84 for rh ∼50% to 95% at low frequencies, where ω is the angular frequency. An inductive effect is also observed in a low-humidity atmosphere, which implies desorption of water vapor with the regeneration of the adsorption sites.     

TiO2纳米粒子的制备及改性

近年来关于纳米TiO2粒子的制备方法报道的很多,本文对各种制备纳米TiO2粒子的方法作了阐述和比较。简单地介绍了纳米TiO2粒子的改性技术。     

TiO2纳米粒子的制备及表征

利用溶胶-凝胶法制备了TiO2纳米粒子,并利用透射电子显微镜、扫描电子显微镜、紫外-可见吸收光谱仪和傅立叶转换红外光谱仪对TiO2纳米粒子的形貌、结构和尺寸进行了表征。结果表明:TiO2纳米粒子为近球形,粒径为12~15nm左右的锐钛矿型纳米晶;TiO2溶胶薄膜中粒子均匀分散,有较好的均一性;TiO2纳米粒子表面富氧,含有较多的TiOH基团;TiO2纳米粒子尺寸对反应体系的pH值很敏感;不同尺寸的纳米粒子在紫外区均有较强吸收,并表现出吸收带边蓝移效应。     

Mechanochemical Synthesis of Visible-light Induced Photocatalyst with Nitrogen and Carbon Doping

Nitrogen and/or carbon doped titania photocatalysts were prepared by a novel mechanochemical method. The prepared powders possessed two absorption edges around 400 and 540 nm wavelengths and showed excellent photocatalytic ability for nitrogen monoxide oxidation under visible light irradiation. Under the irradiation of visible light of wavelength >510 nm, 37% of nitrogen monoxide could be continuously removed by the carbon and nitrogen co-doped titania prepared by planetary ball milling of P-25 titania-10% hexamethylenetetramine mixture followed by calcination in air at 400?C.     

云母铁珠光颜料制备过程中FeCl3与尿素水解反应动力学

测定了均匀沉淀法制备云母铁珠光颜料过程中FeCl3与尿素水解反应浓度的变化规律，建立了各自的水解速率方程，得出FeCl3水解反应的级数α1为0．9级，其活化能Ea1为125．5kJ／mol；尿素水解反应的级数α2为0级，其活化能Ea2为252．8kJ／mol．通过对尿素与FeCl3的水解速率方程进行分析，得出一次加入尿素、连续加入铁盐的新加料方法，可使云母铁珠光颜料制备过程反应液的pH值恒定．