Cu/TiO2催化湿式氧化甲醛废水

甲醛废水排放入水体后,破坏生态系统,影响人们的身体健康。考察了以自制的Cu/TiO2为催化剂,用催化湿式氧化的方法降解甲醛废水的情况。通过优化反应条件,在180℃、pH=5、0.5 MPa、催化剂量为6 g/L时反应2 h,TOC的去除率高达85%,且Cu2+和Ti4+基本没有流失。此外还检测了甲醛溶液中甲醇变化情况和经处理后甲醛废水的降解产物甲酸。结果表明,以Cu/TiO2为催化剂的催化湿式氧化能有效地降解甲醛废水。     

催化湿式氧化法处理含酚废水

进行了CuO/Al2O3、CuO MnO2/Al2O3、CuO K2O/Al2O3、CuO/CeO2催化剂在160℃和1.6MPa的氧气压力条件下,催化氧化法处理含酚废水的实验,结果表明催化剂CuO/CeO2具有最高的催化活性,COD为3000mg/L左右含酚废水,反应50min后降解97%。并测定了在135～165℃和1.6MPa氧气压力下,加入催化剂CuO/Al2O3氧化含酚废水的COD与时间的的关系,求取了反应的动力学方程。初步探讨了氧分压和溶液的pH对催化氧化反应速率的影响。     

Pt-CeO2/TiO2催化剂催化湿式氧化苯酚废水的研究

以TiO2为载体,利用分步浸渍法制备了Pt-CeO2/TiO2、Pt-ZrO2/TiO2、Pt-La2O3/TiO2、Pt-Pr2O3/TiO2和Pt-SnO2/TiO2催化剂,并催化湿式氧化高浓度苯酚废水。Pt-CeO2/TiO2催化剂的活性最好,在反应温度为160℃、氧分压为2.25 MPa,反应时间为2 h的条件下,苯酚和COD的去除率分别为87.53%和72.06%。进一步研究助剂含量对催化剂性能的影响,当CeO2负载量为12.5%时,催化剂Pt-CeO2/TiO2的催化性能最佳。XRD和TEM结果表明,助剂CeO2的引入起到降低Pt的粒径,提高Pt在载体表面的分散度的作用。     

催化湿式氧化吡虫啉农药废水的研究

采用湿式氧化法在2 L反应釜中处理吡虫啉农药废水,研究温度、硝酸盐和Cu/Ce复合金属氧化物作催化剂对废水氧化程度的影响。结果表明,采用湿式氧化技术处理吡虫啉农药废水的适宜操作温度为190 ℃,硝酸铜对吡虫啉农药废水虽有较高的催化活性,但存在Cu²⁺ 和Ce⁴⁺的溶出;通过共沉淀法制备了一系列Cu/Ce催化剂,用于催化湿式氧化吡虫啉农药废水。Cu/Ce催化剂对吡虫啉农药废水具有较好的催化活性;优化催化剂的设计和制备方法,不但可以提高COD的去除率,而且可有效降低Cu²⁺和Ce⁴⁺的溶出量,使该类催化剂具有广阔的使用前景。     

湿式催化氧化法处理含酚清洗废水的研究

针对化工集装罐清洗废水中含酚废水浓度大的特点,采用湿式催化氧化法进行了较深入的研究。对硝酸铜-AC制备CuO/AC催化剂过程中的浸渍液浓度、焙烧温度、焙烧时间等影响因素进行探讨;用该催化剂催化氧化降解模拟苯酚废水,对反应温度、氧化剂投加量、催化剂投加量、反应时间等工艺参数进行优化,确定最佳反应条件并进行了应用研究。研究结果表明,硝酸铜-AC制备CuO/AC催化剂的最佳条件为:硝酸铜质量分数为3%,浸渍温度为30℃,浸渍时间为6 h,焙烧温度为300℃,焙烧时间为3 h。湿式催化氧化法处理苯酚废水的最佳工艺条件为:反应温度为170℃,反应时间为1 h,催化剂投加质量浓度为2 g/L,氧化剂H2O2按m(H2O2)∶m(COD)=3投加,含酚清洗废水的COD去除率达到95%以上,处理效果显著。     

SnO2对CuO-CeO2/γ-Al2O3催化剂湿式氧化降解苯酚活性的影响

从电子助剂的角度考虑,以SnO2为添加剂,以γ Al2O3为载体,CuO为活性组分,CeO2为助剂,采用分层浸渍与混合浸渍相结合的方式制备出CuO SnO2 CeO2/γ Al2O3负载型湿式氧化催化剂。利用XPS对催化剂进行表征,研究Sn的掺杂对催化剂表面微观结构的影响,进而研究对其催化剂活性的影响。研究证明了Sn的掺杂可以提高催化剂表面Cu 的含量,从而提高催化剂表面晶格氧空位的数量。通过对苯酚的湿式氧化降解,得出催化剂表面晶格氧空位的数量是影响催化剂活性的主要因素。     

壳-核式RuO2-TiO2/CeO2-TiO2复合催化剂的制备及催化湿式氧化性能研究

以CeO2-TiO2为载体,通过化学沉积、纳米活性层包覆、纳米烧结的方法在其表面包覆了RuO2/TiO2纳米层,制备得壳-核式RuO2-TiO2/CeO2-TiO2复合催化剂。通过XRD、XPS、UV-Vis、BET、SEM、TEM等手段对催化剂进行了表征。结果表明:纳米层中的RuO2包覆在TiO2表面,也形成了一种壳-核式结构,TiO2粒子的粒径约15nm,其表面的RuO2厚度约4nm,包覆纳米层后催化剂的比表面积明显增大。以丁二酸为模拟废水,对催化剂的催化湿式氧化活性进行了测试,研究了反应温度、pH等因素对催化湿式氧化活性的影响。与浸渍法制备的催化剂相比,新催化剂催化湿式氧化丁二酸的活性显著提高。乙酸和丙烯酸是丁二酸降解的主要中间产物。     

催化湿式氧化反应用贵金属催化剂的研究进展

对各种催化湿式氧化反应用贵金属催化剂的制备方法以及其处理各种污染物的催化反应性能进行了评述.以Ru为活性组分的贵金属催化剂较其他催化剂不仅具有较大的成本优势,并且其在处理废水中氨氮类污染物时的催化活性最高,着重介绍了以Ru为活性组分的贵金属催化剂.在此类负载型催化剂中,以TiO2或TiO2-ZrO2为载体的催化剂,由于其在热的酸性和碱性反应条件下都具有很好的稳定性,是唯一具有实际应用前景的催化剂.对目前实际应用的催化湿式氧化反应用贵金属催化剂进行了介绍.     

助剂掺杂Cu/Al_2O_3湿式氧化处理造纸废水

以CuO为主活性组分,过渡金属为掺杂组分,在γ-Al_2O_3载体上浸渍制备复合催化剂.对造纸制浆废水采用催化湿式氧化处理,考察Cu负载量,掺杂组分的种类和掺杂量、焙烧温度和时间对催化剂对造纸废水的催化降解性能.结果表明,在Cu的负载质量分数为6%,助剂Mn的掺杂质量分数为4%,700℃下焙烧4h制备出在负载型Cu-Mn二元复合催化剂.在反应温度为200℃,氧气分压为2 MPa的条件下,废水的COD去除率最高可达88.1%.     

含酚废水CWPO金属氧化物催化剂研究进展

催化湿式过氧氧化(CWPO)是处理含酚废水的有效方法之一。综述了近些年广泛研究的Fe基和Cu基等金属氧化物催化剂用于CWPO降解含酚废水的进展和现状,重点介绍了载体材料、助剂和反应条件对催化剂催化性能的影响,并展望了CWPO催化剂应用前景。     

Self-organized nano-crystallisation of BaF2 from Na2O/K2O/BaF2/Al2O3/SiO2 glasses

In glasses with the compositions (100 ? x)(2Na₂O·16K₂O·8Al₂O₃·74SiO₂)xBaF₂ (with x = 0 to 6), the glass transition temperature decreases with increasing BaF₂-concentration. Samples with x = 6 were thermally treated at temperatures in the range from 500 to 600 °C for 5–160 h. This leads to the crystallisation of BaF₂. The quantity of crystalline BaF₂ increases with increasing time of thermal treatment, while the mean crystallite size remains constant within the limits of error. The glass transformation temperature of partially crystallised samples increases with increasing crystallisation time and approaches a value equal to the temperature, at which the samples were treated. This is explained by the formation of a highly viscous layer enriched in SiO₂ which is formed during crystallisation. This layer acts as a diffusion barrier and hinders further crystal growth.     

Prediction of Immiscibility Boundaries of the Systems K2O-SiO2, K2O-Li20-SiO2, K20-Na2O-Si02, and K2O-BaO-SiO2

In earlier work, a prediction method of the immiscibility boundary of a ternary silicate glass system was developed involving two known binary immiscibility boundaries and a measured immiscibility temperature of one ternary glass composition. In the present work, the method is extended to the case where one of the two binary immiscibility boundaries is not known and is applied as an example to ternary silicate systems containing K₂O. First, the immiscibility boundary of the system K₂O-SiO₂ is estimated by measuring the immiscibility temperatures of three glasses in the system K₂O-Li₂O (or Na₂O)-SiO₂. Using this result the immiscibility boundaries of the systems K₂O-Li₂O-SiO₂, K₂O-Na₂O-SiO₂, and K₂O-BaO-SiO₂ are estimated. The results agree reasonably well with the experimentally determined immiscibility temperatures at selected compositions.     

The System Na2O-CaO-SiO2-H2O

A portion of the quaternary phase diagram for Na₂O-CaO-SiO₂-H₂O has been constructed. Plotting concentrations as their 10th roots allows compounds having solubilities which differ by several orders of magnitude to be represented on a single diagram. The compositional relationships among sodium-substituted calcium silicate hydrate, calcium-substituted sodium silicate hydrate, calcium bydroxide, a quaternary compound of approximate composition 0.25Na₂O · CaO · SiO₂· 3H₂O, sodium hydroxide monohydrate, and miscellaneous sodium silicate hydrates are presented. The quaternary diagram constructed shows the quaternary compound to exist in equilibrium with sodium-substituted calcium silicate hydrate and calcium hydroxide. Conditions in concrete pore solutions which favor the formation of this quaternary compound may also favor the occurrence of the alkali-silica reaction.     

复合固体超强酸SO42-/ZrO2-Al2O3催化合成乳酸正丁酯的研究

合成了几种不同Zr、Al原子比的SO42-/ZrO2-Al2O3复合固体超强酸,将其用于催化乳酸与正丁醇的酯化反应,均有较好的催化活性,尤以ZrAl=12的催化效果最好,经济性优于ZrO2超强酸催化剂.其最佳反应条件为酸醇摩尔比为13,催化剂用量为乳酸质量的10%,反应时间2～2.5h,酯化率达96.9%.该催化剂具有制备容易、催化活性高、不污染环境、可重复使用的优点.     

Some Properties of the System Na2O-NaF-B2O2-H2O

It was first shown that the enamel slips which have the best suspnding characteristics contain equal amounts of Na₂O and B₂O₃ and at least a moderate amount of NaF. The solubilities of mixtures of Na₂O, NaF, and B₂O₃ were then investigated. The pH of these solutions and the primary crystalline phases separating on evaporation also were determined. The solubility data obtained at room temperature were summarized. When the solutions were evaporated, NaF was the first crystalline phase to separate from a large proportion of the mixtures investigated. It was concluded that the desirable handling characteristics of enamels whose mill liquors contain the proper proportion of Na₂O, NaF, and B₂O₃ are not due to the formation of complex salts but to the following combination of properties: (1) the presence of salts with a moderate solubility which changes very slightly with temperature, (2) a moderate pH of about 10 in a probably well-buffered solution, (3) a relatively stable crystalline material, NaF, as a primary phase, and (4) a secondary phase which crystallizes slowly with relatively little shrinkage.     

固体超强酸SO^2—4／TiO2催化合成尿囊素的研究

用固体超强酸SO42/TiO2为催化剂,以尿素和乙醛酸为原料合成了尿囊素。得到最佳条件为TiO2在1mo1·L-1H2SO4溶液中浸渍12h,再在600℃焙烧3h;尿素与乙醛酸摩尔比3.51,催化剂9％,时间3h,温度72℃～75℃,产率达57.4％。     

Photocatalytic activity of Cu2O/TiO2, Bi2O3/TiO2 and ZnMn2O4/TiO2 heterojunctions

Cu₂O/TiO₂, Bi₂O₃/TiO₂ and ZnMn₂O₄/TiO₂ heterojunctions were studied for potential applications in water decontamination technology and their capacity to induce an oxidation process under VIS light. UV–vis spectroscopy analysis showed that the junctions-based Cu₂O, Bi₂O₃ and ZnMn₂O₄ are able to absorb a large part of visible light (respectively, up to 650, 460 and 1000 nm). This fact was confirmed in the case of Cu₂O/TiO₂ and Bi₂O₃/TiO₂ by photocatalytic experiments performed under visible light. A part of the charge recombination that can take place when both semiconductors are excited was observed when a photocatalytic experiment was performed under UV–vis illumination. Orange II, 4-hydroxybenzoic and benzamide were used as pollutants in the experiment. Photoactivity of the junctions was found to be strongly dependent on the substrate. The different phenomena that were observed in each case are discussed.     

Phase Diagrams for the Systems MgCl2-MgF2, CaCl2-MgF2, and NaCl-MgF2

Equilibrium phase diagrams for the systems MgCl₂-MgF₂, CaCl₂-MgF₂ and NaCl-MgF₂ were determined by differential thermal analysis, thermal analysis, and temperature-composition equilibrium techniques. Simple eutectics were observed at 78.0±0.5 mol% MgCl₂ and 628°±2°C in the MgCl₂-MgF₂ system, at 87.5±0.5 mol% CaCl₂ and 694°±2°C in the CaCl₂-MgF₂ system, and at 95.5±0.5 mol% NaCl and 786°±3°C in the NaCl-MgF₂ system. The phase diagrams determined for these systems were compared with phase diagrams that were computed using Temkin's model. The phase diagrams of the CaCl₂-MgF₂ and NaCl-MgF₂ systems were also compared with diagrams that were computed using the expression suggested by Flood et al. for reciprocal systems. The experimentally determined and computed phase diagrams agreed for the MgCl₂-MgF₂ system but not for the CaCl₂-MgF₂ and NaCl-MgF₂ systems.     

Crystallization of zeolite L from Na2O-K2O-Al2O3-SiO2-H2O system

Zeolite L powder was prepared from the substrate mixture of Na₂O-K₂O-Al₂O₃-SiO₂-H₂O system at temperatures of 373-443 K. In order to investigate the factors which influence the synthesis outcome, a reference system which yields zeolite L in a reproducible manner was chosen and subjected to controlled changes in synthesis parameters. The crystalline zeolite L samples obtained were characterized by elemental chemical analysis, X-ray diffraction (XRD), and scanning electron microscopy (SEM). It was established that phase purity, morphology, and the size of crystals of crystalline product were affected by molar ratios of the substrate, such as SiO₂/Al₂O₃, (K₂O+Na₂O)/SiO₂, Na₂O/(K₂O+Na₂O), and H₂O/(K₂O+Na₂O). Amorphous silica powder (Zeosil) was the preferred silica source, and the crystallization rate was promoted by introducing gel aging, seeding, and rapid heating rate.