环境友好型溴虫腈纳米农药的制备及其光降解活性

采用硬脂酸对纳米Ag/TiO2颗粒表面进行亲脂性改性,将溴虫腈原药、改性后的Ag/TiO2和适当的添加剂经高速剪切制成颗粒分布均匀、平均粒径约为100 nm的纳米农药制剂。光降解实验表明,该制剂在黑暗15 d内,分解率低于0.5%,而在室内(不受太阳光直射)放置15 d时,溴虫腈纳米制剂分解率达到12.3%,在太阳光直射下放置3 d的分解率为67.5%,紫外光照22.5 h时,纳米制剂分解率是常规制剂的7.9倍。纳米溴虫腈制剂有较高的光降解活性。     

环保型溴虫腈纳米农药制剂的应用

用硬脂酸对Ag/TiO₂表面进行了改性,其表面由亲水性变为亲油性.将溴虫腈农药、改性Ag/TiO₂和相应的添加剂混合制成颗粒分布较均匀、平均粒径约为100 nm的纳米农药制剂.溴虫腈纳米制剂光降解实验表明,在黑暗中稳定,在有光线的室内放置15 d的分解率为15.8%,在太阳光直射下放置3 d的分解率为69.0%.紫外光照22.5 h时,纳米制剂分解率是常规制剂的9.2倍.溴虫腈纳米制剂室内、田间毒力试验表明,纳米制剂比常规制剂具有更强的毒力,其LC₅₀为8.95 mg•L^-1,是乳油毒力的1.77倍.在田间药效对比试验中,施药剂量减少一半条件下,纳米制剂防治甘蓝斜纹夜蛾的田间防效优于溴虫腈乳油,药后1 d和3 d的校正防效分别高出4.89和3.05个百分点.土壤、植物的残留试验表明,纳米制剂在甘蓝、土壤中的消解较快,其t_1/2分别为3.91 d和1.27 d,而溴虫腈SC的t_1/2分别为 8.64 d和3.27 d.     

甲基嘧啶磷稳定剂的研究

叙述了影响有机磷农药分解的原因及控制其分解的对策 ,并针对甲基嘧啶磷的结构及其性质 ,进行了稳定剂的筛选。实验结果表明 ,选用ZRQ - 10 0或NPE - 90 1为甲基嘧啶磷原药稳定剂 ,在 5 4± 2℃ / 14d贮存条件下 ,其相对分解率分别为 3 98%和 3 5 6 %     

超声——化学氧化法降解水中甲基橙的研究

用超声波辐射甲基橙溶液,研究了溶液浓度、溶液酸碱度(pH值)、外加H2O2、外加纳米TiO2光催化剂和联合紫外光照射对甲基橙的降解效果。结果表明,甲基橙溶液浓度在10~40 mg/L范围内,其降解率与溶液浓度呈良好的线性关系(相关系数r=0.9917~0.9987);pH=3的酸性条件下甲基橙的降解率是pH=11的2倍;加入3g/L H2O2能使降解率提高40%;加入纳米TiO2和联合紫外光照射使甲基橙的脱色率达100%,超声波、纳米TiO2和紫外光三种作用存在协同效应。     

硫掺杂纳米TiO2可见光催化剂的制备及光催化活性

用钛酸丙酯和硫脲为原料在煅烧条件下制备了硫掺杂纳米TiO2光催化剂,用XRD、XPS、TEM和UV-vis吸收光谱对催化剂进行了表征;分别以紫外光与太阳光为光源,甲基橙为目标降解物,评价了催化剂的光催化活性。结果表明,500℃煅烧的硫掺杂TiO2在紫外光区和可见光区的吸光度比纯TiO2提高了约0.23~0.46;经40~50 min降解,其在紫外光和太阳光下对甲基橙的降解率比纯TiO2分别提高了32%和69%。TEM结果表明,500℃煅烧的硫掺杂TiO2的粒径约为15~16 nm;XRD分析结果表明,硫掺杂能够促进TiO2从锐钛矿相向金红石相的转变,减小催化剂的晶粒粒径;XPS分析结果指出,硫原子的氧化态为+6,S6+部分取代了TiO2晶格中的Ti4+,形成了硫掺杂的TiO2光催化剂。     

壳聚糖改性纳米TiO2的制备及可见光催化性能

采用溶胶-凝胶法制备了壳聚糖(CS)改性纳米TiO2复合粒子。以甲基橙为目标污染物,通过碘钨灯照射进行可见光催化反应研究。考察了合成条件对TiO2/CS纳米复合粒子光催化性能的影响,得出了制备可见光高催化活性TiO2/CS纳米复合粒子的最佳条件:壳聚糖含量1wt%,焙烧温度280℃,焙烧时间2h,pH值为5,凝胶温度25℃。最佳条件下制备的TiO2/CS纳米复合粒子在太阳光下能快速催化降解甲基橙溶液,60min后甲基橙降解率达到99%,表明TiO2/CS纳米复合粒子是一种利用太阳光处理废水的新材料。     

多种光源下氮掺杂TiO_2光催化降解染料废水的研究

以尿素为氮源,采用溶胶-凝胶法制备了氮掺杂纳米TiO2粉末,以甲基橙溶液为模拟染料废水,分别在可见光、模拟太阳光和紫外光条件下,研究了氮掺杂纳米TiO2光催化降解染料废水的性能。结果表明:氮掺杂可以提高TiO2的可见光催化活性;氮含量和煅烧温度对氮掺杂TiO2光催化活性影响较大,n(N)∶n(Ti)为10%且经500℃煅烧的氮掺杂TiO2在可见光和模拟太阳光下均具有最佳的光催化活性;然而在紫外光下,氮掺杂TiO2的光催化活性低于未掺杂的TiO2样品。     

钛铁矿制备TiO2及其光催化性能的研究

以钛铁矿为原料,采取SAS工艺制备TiO2及掺铁的光催化剂,对制药废水进行了降解实验。研究了煅烧温度、掺铁比例、投加量、pH值、附加曝气等条件对废水降解率的影响。结果表明:700℃的TiO2在两种光源(紫外光和太阳光)下3h的降解率分别为79%和75%;太阳光下掺铁0.5%的TiO23h降解率为82%;两种光源下的最佳投加量分别为2.0g/L和2.5g/L,降解率分别为79%和85%;pH=2的废水3h降解率分别为83%和79%;附加曝气的废水降解率比其它两种的高13%和11%。     

聚噻吩敏化TiO_2复合材料的制备和光催化性能

以无水FeCl3为氧化剂,在CHCl3中采用原位氧化聚合法制备了一系列不同噻吩与TiO2摩尔比〔n(Th)/n(TiO2)〕的聚噻吩敏化TiO2(PTh/TiO2)复合材料。用TEM、FTIR、XRD、DRS和PL对复合材料进行了表征。用苯酚的光催化降解反应研究了复合材料在紫外光和太阳光下的光催化活性。结果表明,PTh的修饰减轻了复合纳米粒子之间的团聚,但对TiO2的晶体结构无影响,复合材料粒径25～30nm。PTh的敏化作用可使复合材料吸收200～800nm的光。两种光源下,复合材料的光催化活性均优于纯TiO2,当n(Th)/n(TiO2)=0.04时达最佳。紫外光下,200min时苯酚降解率达76.39%,太阳光下,120min时苯酚降解率达88.27%,较纯TiO2光催化活性分别提高了19.7%和31.53%。     

过氧改性纳米TiO2溶胶的制备及其光催化性能

以硫酸氧钛为钛源,过氧化氢为络合剂,采用低温水热法制备了过氧改性纳米TiO2溶胶,并对制备过程中的影响因素进行了研究,同时,通过甲醛废水模型体系考察了溶胶的光催化活性。采用X射线衍射、透射电镜、紫外-可见漫反射光谱等测试手段对TiO2进行了表征。结果表明,当水解反应pH值为8.0,硫酸氧钛浓度为0.10 mol/L,陈化时间为24 h,Ti4+/H2O2物质的量比为1∶4,水热反应温度和时间分别为100℃和6～8 h时,可制得直径20nm、长30 nm,结晶良好的锐钛矿过氧改性纳米TiO2和分散均匀的溶胶。经紫外光和太阳光光照180 min后,过氧改性纳米TiO2溶胶对甲醛的降解率分别为95.3%和31.8%,优于相同条件下P25的光催化性能(69.7%和21.1%)。     

纳米TiO2（N）的制备及其可见光响应的研究

以纳米TiO2为原料,六亚甲基四胺(HMT)为掺杂N源,采用高能球磨法合成了纳米TiO2(N)粉末。利用XRD、FT-IR、UV-Vis光谱、纳米粒度仪和光催化降解实验对其进行结构及光催化性能表征。研究结果表明,经过氮掺杂的纳米TiO2主要为锐钛矿晶型,晶粒尺寸随球磨时间的增加呈变大趋势。对可见光具有良好的吸收性能,其吸收边红移至530 nm左右,禁带宽度减小至2.34 eV。当太阳光照射30 min时,亚甲基蓝溶液的降解率达88%以上,比未掺N的样品提高了7%,体现出良好的可见光催化特性。     

Physico-Mechanical and Degradation Properties of Urea-Modified Chitosan Film Photocured with 1-Vinyl-2 Pyrrolidone

Chitosan and urea modified chitosan films were prepared by solution casting. To improve the physico-mechanical properties of the chitosan/urea films, four formulations were prepared using 1-vinyl-2-pyrrolidon (NVP) (varied from 10–80% by weight) in methanol along with photo-initiator. The films were soaked (1–4 minutes) in the prepared formulations and photo-cured under UV-light at different intensities (5–35 pass). The physico-mechanical properties, polymer loading, gel content, water uptake and simulating weathering test of the NVP grafted photocured chitosan/urea film were carried out. Degradation of the chitosan/urea film was also observed. The scanning electron micrographs of the photo-cured chitosan/urea film showed smooth surface, compact and homogeneous structure.     

微波辐射加热制备纳米TiO_2光催化剂及光催化活性

采用溶胶-凝胶法和微波辐射技术相结合制备了纳米TiO2光催化剂,用XRD和SEM对催化剂进行了表征。以甲基橙为模拟污染物,高压汞灯为光源,考察了微波功率、辐射时间等因素对TiO2光催化活性的影响。结果表明:采用微波分三阶段辐射加热,加热时间为19.5 min时,制得的光催化剂催化活性较高,其对甲基橙的降解率90 min内可达98.1%;与传统加热法相比较,采用微波辐射加热能够显著缩短加热时间,改善光催化活性。     

Photo-induced Surface Property on Transparent Mesoporous Silica Thin Films Containing Single-site Photocatalyst

The transparent Ti-containing or Cr-containing mesoporous silica thin films can be prepared on quartz plate using a spin-coating sol–gel method. The spectroscopic characterization has revealed that these thin films contain isolated and tetrahedrally coordinated titanium oxide moieties and chromium oxide moieties in their frameworks, respectively. These mesoporous silica thin films containing metal oxide moieties have demonstrated a strong hydrophilic surface property even before UV-light irradiation and the appearance of the super-hydrophilic property after UV-light irradiation. Especially, the Cr-containing mesoporous silica (CMS) thin film showed the super-hydrophilic property even under visible light irradiation. In the presence of ethylene gas, the polyethylene was successfully formed on the surface of the CMS thin film under UV-light irradiation. After the formation of polyethylene the surface property of the CMS was converted into hydrophobic while keeping its transparency. The isolated and tetrahedrally coordinated titanium oxide moieties and chromium oxide moieties are responsible for these photo-induced surface reactions.     

Solid-phase photocatalytic degradation of polystyrene with modified nano-TiO2 catalyst

A novel photodegradable polystyrene-grafted-TiO₂ (PS-g-TiO₂) nanocomposite was prepared by embedding the grafted-TiO₂ into the commercial polystyrene. Solid-phase photocatalytic degradation of the PS-g-TiO₂ nanocomposite was carried out in ambient air at room temperature under ultraviolet lamp and/or sunlight irradiation. The properties of composite film were compared with those of the pure PS film by methods such as weight loss measurement, scanning electron microscope (SEM), gel permeation chromatogram (GPC), X-ray photoelectron spectroscopy (XPS), FT-IR spectroscopy, and UV-vis spectroscopy. The results show that the photo-induced degradation of PS-g-TiO₂ composite film is significantly higher than that of pure PS film. The weight loss of composite film reached 31.9%, average molecular weight (M_w) of composite film decreased by 53.1%, and the number average molecular weight (M_n) decreased by 73.2% after 396 h of UV-light irradiation. FT-IR analysis and weight loss indicated that the benzene rings in PS-matrix of composite film were cleaved during UV-light irradiation. The photocatalytic degradation mechanism of the films is briefly discussed.     

Photoassisted mineralization of remazole red F3B over NiO/TiO2 and CdO/TiO2 nanoparticles under simulated sunlight

In this work, a series of titania-supported NiO and CdO materials were synthesized by a modified sol-gel process. The prepared photocatalysts were characterized by X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS), and transmission electron microscopy (TEM). The activities of titania-supported NiO and CdO photocatalysts for photocatalytic degradation of Remazole Red F3B (RR) dye, under simulated sunlight, were investigated. The photocatalytic mineralization of an RR dye solution over various NiO-x/TiO₂ and CdO-x/TiO₂ photocatalysts under simulated sunlight was investigated. It was worthy noticing that the photocatalytic activity of titania improved using the prepared catalysts. The prepared TiO₂, NiO-5/TiO₂, and CdO-2/TiO₂ photocatalysts exhibited higher photocatalytic activity under simulated sunlight than did commercial TiO₂. The prepared photocatalysts were stable after photocatalytic degradation of the dye. The observed photocatalytic mineralization of the dye was 51 and 71% over NiO-10/TiO₂ and CdO-2/TiO₂ after 180 min of irradiation, respectively. Juxtaposing a p-NiO-5/TiO₂ semiconductor provided a potential approach for decreasing charge recombination. The prepared photocatalystsNiO-5/TiO₂ and CdO-2/TiO₂ are promising composites for the solar detoxification of textile wastewater.     

掺杂改性纳米TiO_2降解挥发性污染物及产物研究

本文系统研究了水热法制备的铁掺杂纳米Ti O2和氮掺杂纳米Ti O2在可见光照射下对挥发性有机物(volatile organic compounds,VOCs)的降解能力和降解产物.铁掺杂纳米Ti O2和氮掺杂Ti O2对光的吸收边分别红移到540 nm和580 nm;在可见光下具有良好的催化活性,24 h内对挥发性有机物的降解率达20%—50%,降解后的最终产物可能主要为CO2.     

AgBr纳米粒子的制备及其光催化性能的研究

通过简单的沉淀法,加入适量浓度的表面活性剂十六烷基三甲基溴化铵（CTAB）制备纳米AgBr粒子。利用XRD、SEM表征手段证明了所制得的纳米粒子纯度高、粒径小、尺寸分布窄、稳定性好。通过UV-Vis表征可以知道,沉淀法制备的纳米粒子吸收波长范围可至可见光区域。在以紫外光及自然光（太阳光）为光源的条件下,经过60min的光催化降解反应,甲基橙（MO）的降解率可达到96％以上。与纳米二氧化钛粒子和纳米氧化锌粒子光催化性能相比,纳米溴化银不仅催化效率更高,而且在自然光照的条件下仍然可以保持很好的光催化性能。