超声强化二氧化钛催化降解染料废水中甲基橙效果的研究

超声强化TiO2催化降解染料废水中甲基橙的效果受超声辐射时间、TiO2加入量、超声波频率、超声波输出功率等因素影响。实验结果表明：随着超声辐射时间的延长,甲基橙的降解率持续增大;当TiO2加入量为750mg/L,超声频率为25kHz,功率为55W时甲基橙降解效果最佳。研究结果证明,超声波对二氧化钛催化氧化反应有一定的强化作用。     

太阳光下Fenton试剂降解有机染料的研究

研究了甲基橙等有机染料在太阳光和Fenton试剂联合作用下的降解动力学。采用单因子法考察了硫酸亚铁用量、氧化剂双氧水用量和辐射光源等因素对降解效果的影响。结果表明:在优选实验条件下甲基橙的降解效果较好,有机染料的降解过程符合一级动力学。辐射光源对甲基橙的降解速率影响非常大,降解速率随紫外光强度的增强而加快。太阳光下甲基橙的降解速率常数是室内3～4倍,该反应体系在太阳光利用方面具有一定的应用价值。     

Air、pH条件下载银催化剂光降解甲基橙的研究

通过实验研究，在Air气速、pH值条件下用自制的载银催化来降解水溶液中的甲基橙，得出如下结论：（1）在本实验条件下，Ag/TiO2催化剂对甲基橙没有明显的吸附作用。（2）甲基橙的降解速率随气速的增大而增大，反映在本实验中就是溶液中甲基橙的浓度不断地降低，但当气速增大到一定值时，溶液中甲基橙的浓度反而增高，这说明气速有一最佳值4L／min。（3）pH值对甲基橙的降解也有一定的影响，实验表明在pH=2的条件下，载银催化剂对甲基橙的降解效果最好。     

光催化降解溶液中亚甲基蓝的动力学研究

以Sol-Gel法合成的TiO2为光催化剂,研究了紫外光照射下光催化降解水溶液中亚甲基蓝的动力学行为.实验结果表明:TiO2光催化降解亚甲基蓝的反应为一级反应,其反应速率常数为1.67×10-2min-1;亚甲基蓝的降解量随光照强度的增大而增加;催化剂的最佳用量为1.2g/L.     

电气石对TiO2光催化活性的影响研究

采用电气石负载TiO2可见响应光催化功能材料,以甲基橙为降解脱色对象,考查了不同电气石加入量、催化剂质量、pH以及甲基橙浓度对光催化活性的影响。实验结果表明:电气石的加入有利于TiO2光催化活性的提高,其中电气石掺杂量为1%为最佳比例;催化剂加入量的增加有助于甲基橙的降解;在催化剂质量为0.2 g的条件下,甲基橙浓度为40 mg.L-1光催化降解甲基橙的效果最好。     

TiO2光催化氧化降解偶氮染料

研究了催化剂、光源、溶液初始浓度、溶液初始pH值等因素对甲基橙光催化氧化降解反应的影响．实验结果表明,最佳实验条件为：以灼烧的TiO2为催化剂,催化剂的投加量为0,8g·L^-1,采用浸波式紫外灯作光源,甲基橙初始浓度为20mg·L^-1,溶液初始pH=3．该实验条件下,甲基橙一小时脱色率可达81．3％．该研究可为偶氮染料降解提供新的思路．     

纳米二氧化钛制备方法的对比及其降解间苯二酚的研究

采用溶胶-凝胶法、超声水解法制备纳米TiO2,用XRD对两种方法制得粉体进行了表征,对比了两种方法的优缺点。结果表明:超声水解法制得粉体的光催化效果好,且制备工艺简单,对间苯二酚光催化降解符合假一级动力学,速率常数为0.0928min-1,是溶胶-凝胶法速率常数的5.4倍。以超声水解法制得粉体对间苯二酚进行了降解研究,考察催化剂投加量、有机物浓度、溶液pH等因素对间苯二酚降解效果的影响。在最佳实验条件下反应60min,UV-Vis及HPLC均显示间苯二酚降解完全。     

相向双频超声降解罗丹明B(RhB)的实验研究

使用了20 kHz和25 kHz的相向双频超声波降解装置,利用染色法研究了不同频率及功率下超声的空化效应;并将双频超声应用于罗丹明B(RhB)的降解研究,实验结果表明:双频超声(20 kHz +25 kHz)的空化效应大于单频超声(频率分别为20 kHz和25 kHz);在温度20 ±0.5℃、相向双频超声组合(20 kHz,30 W+25 kHz,20 w)方式在同等能耗下对于RhB的降解效果最好,降解率达到10.81％,明显高于同样条件下单频超声和其它功率组合下的双频超声.     

微波法合成纳米FeVO4及其光催化性能

通过微波法合成纳米FeVO4光催化剂,用XRD、SEM、UV-Vis DRS对其进行表征,探究不同Fe:V摩尔比、不同微波反应时间及Cu2+掺杂对产物的形貌、结晶度、粒径以及带隙的影响.结果表明,当Fe:V=1、微波反应6 min时,制备条件较优,获得了粒度比较均匀、尺寸较小、形貌比较规则的FeVO4晶体,且结晶度较高、带隙较窄.选取优化条件下制备的FeVO4与FeVO4:Cu2+,在可见光下进行甲基橙降解试验.在初始甲基橙浓度为10 mg/L、反应160 min时,FeVO4:Cu2+对甲基橙的降解率达到76.4%.     

光催化降解甲基橙过程的评价方法研究

以300W汞灯为光源,纳米TiO2为光催化剂,甲基橙为目标降解物,以分光光度法测定其脱色率,以重铬酸钾法测定其COD降解率,研究了在不同溶液pH值、甲基橙初始浓度及TiO2投加量等条件下的甲基橙光催化降解效率．结果表明,甲基橙溶液脱色率和COD降解率并不一致,脱色比COD降解更容易发生;将脱色率、COD降解率等指标的变化综合考虑,才能更全面准确地判断光催化反应的效率．     

不同分子量壳聚糖的制备及其抑菌性能的研究

本实验在超声波条件下用过氧化氢降解壳聚糖制备低分子量壳聚糖,研究了过氧化氢用量、温度、时间、pH值等对壳聚糖溶液粘均分子量的影响,并对降解产物进行红外光谱分析。探讨了降解产物对大肠杆菌、白色念珠菌、枯草芽孢杆菌的抑菌性能。实验结果表明,超声波协同过氧化氢氧化降解壳聚糖的较适宜条件为:1%(w/v)的壳聚糖溶液,加入3%(v/v)的过氧化氢溶液,pH值约为5.0,数控超声清洗仪工作功率为80%,频率为40kHz,温度设定为(50.0±2.0)℃,随着降解时间不同可得到不同粘均分子量的壳聚糖。降解得到的产物对三种细菌均有抑制生长的效果,其中粘均分子量为5.0×104的壳聚糖的抑菌能力最强,且对大肠杆菌的抑制作用最强。     

Microwave-assisted Fenton-like decolorization of methyl orange solution using chromium compounds

Azo dyes discharged in the environment are persistent organic pollutants （POPs）, which are very difficult to remove. We developed a microwave-assisted Fenton-like process to degrade methyl orange （MO）, an azo dye, with hydrogen peroxide （H2O2） catalyzed by chromium compounds coexisting with MO in the solution. Comparison between the Cr（Ⅲ）-H2O2 and Cr（Ⅵ）-H2O2 systems shows＂ that Cr（Ⅵ） has a stronger and more stable catalytical activity than Cr（Ⅲ）, and Cr（Ⅲ） is more susceptible to a change in the acidity or alkalinity of the reaction system. With a Cr（Ⅵ） concentration of 10 mmol L^-1 or a Cr（Ⅲ） concentration of 12 mmol L^-1 in the solution under the microwave irradiation of a power larger than 300 W for 3 min, 10 mmol L^-1 H2O2 can degrade more than 95% of 1 000 mg L^-1 methyl orange; when the microwave power is increased to 700 W, the same amount of H2O2 can degrade all methyl orange in the solution with the same amount of Cr（Ⅵ ） catalyst. Ultraviolet-visible spectrography indicates the cleavage of the azo bond in methyl orange after treatment, suggesting the potential o of this Fenton-like process to degrade azo dye POPs. Reusing waste chromium compounds coexisting with dyestuff in wastewater to catalyze the degradation of azo dyes could be a cost-effective technique for azo dyes and chromate manufacturers and/or users to treat their wastewater and prevent POPs from endangering the environment. This is of particula importance to controlling the water quality of the Three Gorges Reservoir.     

高频脉冲电源参数对 Fe-ZrO2复合电沉积镀层纳米含量的影响

为改善低温镀铁工艺镀层的耐磨损耐腐蚀性能,提高镀层表面硬度,以GKDM系列高频脉冲电镀电源为实验复合电沉积工艺电源并配合超声．机械搅拌制备纳米Fe-ZrO2镀层。研究了高频脉冲电源参数：峰值电流导通（TON）、关闭（TOFF）时间;一组正脉冲（TF）负脉冲（TR）的工作时间对镀层表面纳米含量的影响。结果表明当GKDM系列高频脉冲电源TON=20×0．1ms,TOFF=80×0．1ms时,纳米沉积分布均匀致密,质量分数高。     

纳米TiO_2催化超声降解染料工业废水的研究

采用纳米TiO2为催化剂,超声辐照为主要手段对实际印染工业废水进行了降解实验研究,考察了各种反应参数对印染废水降解效果的影响。结果表明,纳米TiO2对印染工业废水的超声降解效果具有明显的辅助和提高。当超声波频率为45kHz,功率为200W,溶液初始pH值为2.63,超声反应时间为150min的条件下,印染工业废水的COD去除率为73%,而同样条件下,投加750mg/L纳米TiO2,其超声降解废水COD去除率可达90.2%。     

Investigating the potential of using acoustic frequency on the degradation of linear alkylbenzen sulfonates from aqueous solution

The effectiveness of using acoustical (sonochemical) reactor for degradation of linear alkylbenzen sulfonate (LAS) from aqueous solution was investigated. LASs are anionic surfactants,found in relatively high amounts in domestic and industrial wastewaters. In this study,experiments on LAS solution were performed using methylene blue active substances (MBAS) method. The effectiveness of acoustical processor reactor for LAS degradation is evaluated with emphasis on the effect of treatment time and initial LAS concentration. Experiments were performed at initial concentrations of 0.2,0.5,0.8 and 1.0 mg/L,acoustic fre-quency of 130 kHz,applied power of 500 W and temperature of 18 °C～20 °C. At the conditions involved,LAS degradation was found to increase with increasing sonochemical time. In addition,as the concentration increased,the LAS degradation rate de-creased in the acoustical processor reactor.     

Liver fibrosis identification based on ultrasound images captured under varied imaging protocols

INTRODUCTION There are more than 20 million chronic hepatitis patients in China and 300,000 people die of liver related disease every year, which is widely recog- nized as an emerging public health crisis. Moreover, liver damage can cause higher than normal amounts of collagen fiber deposits in the extra-cellular spaces of the liver cells and cause the liver cells to lose blood and lead to liver fibrosis, which is a necessary stage to cirrhosis and a reversible consequence, so it is critic…     

一个用于体外评价超声造影剂显影效果的系统（英文）

构建并评价了一个用于体外研究超声造影剂显影效果的系统,该系统包括一套数字化B型超声诊断仪Belson3000A、仿组织超声体模和用于图像量化分析的软件.制备了具有不同反射强度的仿组织超声体模,通过对这些体模材料超声成像,研究了B超系统的线性范围、参数设置和系统的重复性等.超声成像设置为：输出声功率为4.8 ～12.3mW,探头的中心频率为3.5MHz,总增益为50dB.利用该系统,对自制备的表面活性剂微气泡和一种商用造影剂进行了显影成像.结果表明超声图像的灰度值随声功率的增加而增大,强反射特性的超声体模成像时,这种增加趋势更明显.该系统适合用于体外评价超声造影剂的显影效果,为体外表征超声微气泡造影剂的显影能力提供了一种简单、有效、实时的评价方法.     

新型晶闸管感应加热电源研究

中频电源已广泛应用于工业加热领域？新型晶闸管感应加热电源采用成熟的变频技术,由全控型器件构成串联谐振式逆变电路,解决了工频加热效果差和浪费电能等问题。中频感应加热电源采用IGBT作为开关器件,可工作在10HZ-10KHZ,具有功率调节范围宽、频率变化小的优点,适用于中小功率系统。     

Preparation and electrochemical application of praseodymium modified TiO<Subscript>2</Subscript>-NTs/SnO<Subscript>2</Subscript>-Sb anode by cyclic voltammetry method

A Pr-doped TiO₂-NTs/SnO₂-Sb electrode was prepared by a simple method, cyclic voltammetry(CV). The methyl orange(MO)aqueous solution was selected as a simulated wastewater. The ordered microstructural TiO₂-NTs substrate was synthesized by an electrochemical method to obtain large specific surface area and high space utilization. The phase structure, electrode surface morphology and electrochemical properties of electrodes were characterized by XRD, SEM and electrochemical technology, respectively. The results showed that praseodymium oxide was successfully doped into the SnO₂-Sb film by CV method. Due to the doped Pr, the oxygen evolution potential increased from 2.25 V to 2.40 V. The degradation of MO was investigated by UV-vis. The C _t /C ₀ (φ) was studied as a function to obtain the optimal parameters, such as the amount of doped Pr, current density and initial dye concentration. In addition, the degradation process followed pseudo-first-order reaction kinetics and the rate constant was 0.099 3 min^-1. The result indicated that the introduction of Pr reduced the formation of oxygen vacancies or enhanced the formation of adsorbed hydroxyl radical groups on the surface, thus leading to better activity and stability.