钛基二氧化铅电极的制备及其对甲基橙的降解

以电沉积法制备Ti/PbO_2电极,采用SEM、XRD、XPS等检测方法分析了Ti/PbO_2电极表面的形貌、物相及元素化学态,发现电极表面镀层的晶相主要为β-PbO_2,并且PbO_2镀层的底层晶胞致密、大小均匀;活性层晶胞粗糙度较大,比表面积大。通过测定电极在甲基橙溶液中的析氧极化曲线得到其析氧电位在1.8V vs.SCE左右,有较高析氧过电位。并采用该电极作阳极,对10mg/L的甲基橙溶液进行降解。结果表明:在电流密度为36mA/cm~2下处理12min可使甲基橙的去除率接近100%,有较高的电催化活性。     

Terminal double bonds in the alkenes and acetates of defensive secretion from the thrips Suocerathrips linguis Mound & Marullo, 1994 (Thysanoptera: Phlaeothripidae)

Defensive secretions of adult males and females of the subsocial thrips Suocerathrips linguis were examined using gas chromatography–mass spectrometry (GC–MS). The samples contained six long-chain acetates and five aliphatic alkanes and alkenes. Whole-body extracts yielded six methyl esters of fatty acids as well as hexadecyl acetate. Structures of the two main components, (11Z)-icosa-11,19-dienyl acetate and octadecyl acetate, were confirmed. The third most abundant substance was identified as octadec-17-enyl acetate, which is a new natural product. In addition, (9Z)-octadec-9-enyl acetate was identified along with other acetates. Pure icosadienyl acetate was found to remain liquid down to −15°C, and is the solvent for the solid components of the secretion cocktail. A tentative biosynthetic pathway for all of the 12 acetates, alkanes and alkenes is discussed, considering especially the components with terminal double bonds that are uncommon in Thysanoptera and other insects.     

微乳液法合成掺硫纳米TiO_2及其光催化性能研究

以钛酸四丁酯为钛源,硫脲为掺硫前驱物,采用聚乙二醇辛基苯基醚（Triton X-100）/正己醇/环己烷/氨水的微乳液体系合成了掺硫的纳米TiO2粉体;对其结构进行了表征,以甲基橙为目标降解物考察了其光催化性能。烧结温度通过影响TiO2的晶型转变和颗粒尺寸来影响其光催化性能,随着烧结温度的升高,TiO2的光催化性能先是提高,然后迅速降低;在600℃烧结2 h时催化剂的降解性能达到最佳。掺杂硫可提高TiO2的光催化活性,随着掺杂量的增加,催化剂对甲基橙的降解率先快速增加然后缓慢降低,当掺杂量为S/Ti（摩尔比）=0.01∶1时TiO2的光催化降解效果最好。催化剂在用量较小时迅速提高TiO2的光催化降解性能,而后随着用量的增大反而降低,当催化剂用量为1.5 g/L时,对甲基橙的降解效果最好。     

How do different process options and evaluation settings affect economic and environmental assessments? A case study on methyl methacrylate (MMA) production processes

We present an investigation on how economic and environmental assessment results change when different process options or evaluation settings are considered. As the main case study the production technology of methyl methacrylate (MMA) is investigated. Six commercial processes using different reaction routes are modelled and evaluated with respect to their economic and environmental performance. On these six base case models different process options and evaluation settings are considered and the resulting impacts on the assessment results are quantified. Major findings of the study are that the more decision-variables become fixed, the smaller becomes the impact of the decisions still to be taken—but not only with respect to the economic performance but also with regard to the environmental assessment result. Along the process development steps the potential impacts on the economic and environmental performance decrease to the same degree. The results obtained for the evaluation settings do not show such a systematic pattern as those for the process options. This finding indicates that decision makers face many options in the economic and especially the environmental assessment of chemical processes which might lead to quite different magnitudes in variability due to either the choice of method or the choice of method parameters. This paper demonstrates that the resulting variability might be crucial with respect to the decision making outcome.     

Electrochemical incineration of high concentration azo dye wastewater on the in situ activated platinum electrode with sustained microwave radiation

In this study, an in situ microwave activated platinum electrode was developed for the first time to completely incinerate the azo dye simulated wastewater containing methyl orange. The experiments were carried out in a circulating system under atmospheric pressure. Azo bond of methyl orange was partly broken on Pt, certain decoloration was reached, and the total organic carbon was not removed effectively without microwave activation. However, methyl orange was mineralized completely and efficiently on the in situ microwave activated Pt. 2,5-Dinitrophenol, p-nitrophenol, hydroquinone, benzoquinone, maleic and oxalic acids are the main intermediates during degradation of methyl orange. Aromatic products are the main substances leading to the poisoning of Pt and decrease of electrochemical oxidation efficiency, so methyl orange removal can not be carried out thoroughly. However, the intermediates were broke down quickly with in situ microwave activation promoting the mineralization of methyl orange on Pt.     

陶瓷负载Ag、Ce共掺杂TiO_2光催化剂降解甲基橙的研究

以陶瓷为载体,采用溶胶-凝胶法制备了银离子和铈离子共掺杂TiO2的负载型光催化剂——T-AC/陶瓷,研究了pH值、双氧水用量、催化剂用量、紫外灯强度、废水的初始浓度等因素对T-AC/陶瓷光催化剂降解甲基橙染料废水的影响。结果表明,当pH为2、双氧水用量为0.5 mL/100 mL、催化剂用量为3 g/L、紫外灯功率为20 W、废水初始浓度为10mg/L时,甲基橙的降解率可达85.9%,并且甲基橙的光催化降解属于一级动力学方程,T-AC/陶瓷催化剂有较高的活性和稳定性,在废水处理中具有较好的应用前景。     

植物作为反硝化碳源

研究得到一种新型的筛选反硝化碳源的方法:可以通过比较材料浸出液的C/N值,筛选出有效的反硝化碳源;对芦苇秸秆、梧桐黄叶、梧桐绿叶、橘树叶、玉米秸秆和玉米芯6种材料浸出液的C/N值进行了研究,其中当以叶片作为反硝化固相碳源时,应该选取新鲜叶片作为研究对象。橘树叶和玉米芯均属于良好的反硝化碳源。以驯化后的河泥作为反硝化污泥,可以利用橘树叶或者玉米芯作为反硝化固相碳源,进行持续脱氮除磷反应,其中橘树叶脱氮效果强于玉米芯,而玉米芯除磷能力强于橘树叶。扫描电镜实验表明,橘树叶和玉米芯均适合作为生物膜载体。     

沸石负载Cu_2O光催化剂降解甲基橙

采用化学沉积法,以Cu SO4·5H2O和Na2SO3为原料,以人造沸石为载体,在HAC-Na AC缓冲溶液中制备了沸石-Cu2O复合型光催化剂。在仿日光光源照射下,分别从降解时间、甲基橙初始浓度及初始p H、降解温度等不同方面考察了对复合光催化剂降解甲基橙的影响。结果表明,当甲基橙初始浓度为25 mg/L、初始p H在7.00~10.00之间,降解温度为40℃,复合型光催化剂对甲基橙的降解效果最好;样品重复性使用实验表明,沸石-Cu2O复合光催化剂在可见光区具有良好的光催化活性和稳定性;离子干扰实验证明,Cl-浓度控制在1.2 g/L之内时对甲基橙降解效果影响较小。     

磁性活性炭催化臭氧氧化降解水中甲基橙

通过浸渍法制备了钕铁硼磁性活性炭(Nd Fe B/AC),采用SEM和VSM技术对其进行了表征,并将其作为非均相催化剂用于臭氧氧化降解水中甲基橙(MO)。表征结果显示:Nd Fe B/AC具有硬磁特性;当m(Nd Fe B)∶m(AC)=1∶2时,其比饱和磁化强度和比剩余磁化强度分别为15.9 A·m2/kg和6.0 A·m2/kg,矫顽力可达104.5k A/m。实验结果表明:在Nd Fe B/AC投加量为3.0 g/L、初始溶液p H为5.0、初始MO质量浓度为20 mg/L、臭氧质量浓度为15.0 mg/L、室温的条件下反应40 min,MO降解率达93.9%,显著优于投加AC的64.4%;AC和Nd Fe B/AC催化臭氧氧化降解MO的反应过程均遵循一级动力学规律,且Nd Fe B/AC的反应速率常数为AC的近3倍。     

基于人工神经网络和遗传算法研究锰过氧化酶脱色甲基橙

基于锰过氧化物酶(MnP)氧化脱色偶氮类染料的原理,实验研究MnP对甲基橙的脱色工艺,采用人工神经网络(ANN)和遗传算法(GA)建立脱色模型并优化工艺。建立的ANN模型的误差、相关系数、均方根误差和绝对平均偏差分别为0.0009、0.9971、1.21和6.82,模型有效且能够用于预测和工艺优化。采用GA对ANN模型进行数值寻优,得到的最佳工艺条件为酶液量0.6 mL,Mn2+浓度4 mmol/L,H2O2浓度0.49 mmol/L。该条件下脱色率达到(90.74±0.59)%。ANN耦合GA有效地建立了锰过氧化物酶脱色甲基橙的模型,并优化了工艺参数,为甲基橙脱色的研究提供一定参考。