锑铁复合固体超强酸S2O82-/Sb2O3/Fe2O3催化合成丁醛乙二醇缩醛

以三氯化锑和硝酸铁为主要合成原料,采用溶胶—凝胶法制备出新型固体超强酸催化剂S2O28-/Sb2O3-Fe2O3。并将催化剂用于丁醛乙二醇缩醛的合成。实验结果表明,催化剂制备的最优条件为:焙烧温度为500℃,焙烧时间为3.0 h,(NH4)2S2O8浸泡液浓度为2.0 mol/L。合成丁醛乙二醇缩醛的最佳条件为:n(乙二醇)∶n(丁醛)=1.5∶1.0,反应时间为1.2 h,催化剂用量为0.8 g,带水剂用量为12 mL,丁醛乙二醇缩醛收率可达71.5%。     

纳米α-Fe2O3合成及光催化法处理染料中间体废水

用回流均匀沉淀法合成了纳米三氧化二铁粉体并对其进行了表征,所得产物均为高纯度纳米α-Fe2O3。探讨了干燥方式及煅烧温度等制备条件对催化剂性能的影响。以纳米三氧化二铁为催化剂,高压汞灯为光源,用光催化法处理染料中间体废水。考察了三氧化二铁用量、双氧水用量、pH、反应时间等因素对降解效果的影响,结果表明:Fe2O3/UV/H2O2体系能有效地降低废水中的CODCr,在三氧化二铁用量为1.50 g/L、双氧水用量为1.5‰(体积分数)、pH=3.0、300 W汞灯光照4 h的条件下,废水的CODCr从1 177 mg/L降到533 mg/L,去除率达到56.88%。太阳光/Fe2O3/H2O2体系处理废水,CODCr去除率也可达到48.50%。对处理前后废水中的有机污染物成分进行GC-MS分析,证明该法可有效地降解废水中大多数有害物质。     

O3/H2O2氧化预处理高浓度抗生素制药废水研究

采用O3/H2O2氧化预处理抗生素制药废水,系统考察pH、温度、固体催化剂对污染物去除效果的影响,并研究氧化预处理对厌氧生化工艺的影响,通过气相色谱-质谱分析氧化前后有机物的变化。结果表明,提高温度和降低pH对O3/H2O2氧化有利,添加Mn O2增强了催化氧化效果,而添加活性炭反而不利。氧化预处理降低了难生物降解有机物的浓度,使得厌氧生化工艺对COD去除效果由70. 4%提高到81. 9%。     

反应条件对Fe/γ-Al2O3催化剂去除苯酚废水COD的影响

利用等体积浸渍法制备了一系列Fe/γ-Al2O3催化剂。在温度为30℃时考察了催化剂中Fe含量对苯酚模拟废水COD去除率的影响,发现Fe0.01/γ-Al2O3具有较高的催化活性。研究了苯酚废水的初始pH,反应温度,是否添加H2O2以及是否通入空气时Fe0.01/γ-Al2O3催化剂的性能。结果表明,在反应初始pH为3,温度为30℃,加入100μL H2O2并通入空气的条件下,反应1 h后,苯酚废水COD的去除率最高,约为65%。给出了苯酚在催化剂表面的降解反应模型。     

CuNi/Al2O3催化剂上乙炔选择加氢的研究

采用浸渍法制备了CuNi/Al2O3催化剂,研究了Ni负载量、Cu负载量及n(Cu)/n(Ni)对催化剂上乙炔选择加氢活性和选择性的影响,以及催化剂的还原性能。结果表明:CuNi/Al2O3催化剂中Cu提高了Ni的还原性,使催化剂具有很高的活性及乙烯选择性。随Cu/Ni原子比的提高,催化剂的活性下降,选择性升高,当Ni的负载量为10%、n(Cu)/n(Ni)=0.5时,在反应温度为50℃、反应压力为0.2 MPa、原料气流量为45 mL/min及H2流量为1.5 mL/min的反应条件下,乙炔的转化率达88.98%,乙烯的选择性达74.01%,乙烯收率为65.86%。     

固体超强酸La3+-SO42-/TiO2-Fe2O3催化合成对羟基苯甲酸丁酯

以固体超强酸La3+-SO42-/TiO2-Fe2O3为催化剂合成了对羟基苯甲酸丁酯,考察了原料配比、催化剂用量、反应温度和反应时间等因素对产品收率的影响。试验结果表明:La3+-SO42-/TiO2-Fe2O3是合成对羟基苯甲酸丁酯的良好催化剂,当n(丁醇)/n(对羟基苯甲酸)=4.0,催化剂用量为对羟基苯甲酸质量的6%,反应温度120℃,反应时间4.0 h,对羟基苯甲酸丁酯的收率达到89.27%。     

混凝-O3/H2O2氧化联合工艺处理工业塑料生产废水的研究

针对塑料生产废水成分复杂、色度高等特点,采用混凝-O₃/H₂O₂氧化联合工艺处理,工业塑料废水混凝沉淀分离后,在温度25℃、pH 7、双氧水0.6 mL/L、臭氧(O₃)浓度17.28 mg/L条件下氧化反应30 min,出水COD_Cr为20.49 mg/L,满足工业塑料废水的排放要求,为塑料制造业生产废水降解提供了新的技术手段。     

m(ZnO)/m(B2O3)质量比对低熔点封接玻璃Bi2O3-B2O3-ZnO结构、性能与润湿性的影响

针对真空玻璃封接的性能要求,本文采用高温熔融法制备了一种针对真空玻璃封接的铋系非晶无铅玻璃粉,通过高温X射线衍射、粉末X射线衍射、拉曼光谱、差式扫描量热仪、热膨胀测试和扫描电子显微镜等测试方法,研究了m(ZnO)/m(B₂O₃)质量比对Bi₂O₃-B₂O₃-ZnO玻璃的网络结构、特征温度、热膨胀系数和封接温度的影响。结果表明,增加m(ZnO)/m(B₂O₃)质量比可促进锌氧多面体由[ZnO₄]向[ZnO₆]转变,导致热膨胀系数降低,特征温度升高。当m(Bi₂O₃)∶m(B₂O₃)∶m(ZnO)质量比为80∶7∶13,玻璃具有较低的玻璃化转变温度T_g(371℃)和膨胀软化温度T_f(401℃),热膨胀系数为9.3×10^-6...     

气相氟化四氯乙烯的ZnF2/Al2O3催化剂

采用浸渍法制备了ZnO/Al2O3催化剂,考察了载体Al2O3的焙烧温度对催化剂性能的影响。并对催化剂进行了X射线衍射（XRD）、Raman光谱、氨气程序升温脱附（NH3-TPD）和BET表征。结果表明：随着Al2O3焙烧温度升高,从900 ℃开始,?-Al2O3逐渐向?-Al2O3和α-Al2O3转变,1100 ℃焙烧样品中?-Al2O3的XRD峰强度达到最大。当温度继续升高,?-Al2O3将转变成α-Al2O3。Al2O3载体经过1100 ℃焙烧制得的ZnF2/Al2O3催化剂催化性能最高,当反应温度为300 ℃时,四氯乙烯的转化率为45.7%,HCFC-123(2,2-二氯-1,1,1-三氟乙烷)和HCFC-124(2-氯-1,1,1,2-四氟乙烷)的总选择性为48.2%。     

H3PW12O40/SiO2催化合成苯甲醛乙二醇缩醛

以二氧化硅负载磷钨酸(H3PW12O40/SiO2)为催化剂,苯甲醛和乙二醇为原料合成苯甲醛乙二醇缩醛。探讨H3PW12O40/SiO2对缩醛反应的催化活性,较系统地研究了醛醇物质的量比、催化剂用量、带水剂用量、反应时间等因素对产物收率的影响。实验表明:H3PW12O40/SiO2是合成苯甲醛乙二醇缩醛的良好催化剂;在n(苯甲醛)∶n(乙二醇)=1∶1.5,催化剂用量占反应物量总质量的0.8%,环己烷为带水剂8mL,反应时间45min的最佳条件下,苯甲醛乙二醇缩醛的收率可达60.6%。     

Polycrystalline In2O3 and In2O3/Y2O3 photoanodes

Single crystal In₂O₃ shows promise as a photoanode for the decomposition of water. Because of various difficulties in the preparation of the single crystal material, two simple techniques were developed for the preparation of polycrystalline In₂O₃ anodes. One method involves the thermal decomposition of the nitrate while the other utilizes the chemical vapour deposition technique. Voltammograms and photoresponse spectra of these anodes are compared to the single crystal material. Among other observations, it is noted that the quantum efficiencies of the thermally decomposed films are comparable to the single crystal material. It is also shown that the on-set potential can be shifted to more negative values by forming the mixed oxide In₂O₃/Y₂O₃.     

Bactericidal Effectiveness of O3, O3/H2O2 and O3/TiO2 on Clostridium perfringens

The purpose of this research is to evaluate the bactericidal capacity of different Advanced Oxidation Treatments (AOTs) based on ozone: ozone, ozone/hydrogen peroxide and ozone/titanium dioxide on a wild strain of Clostridium perfringens, a fecal bacterial indicator in drinking water. The dose of ozone consumed ranges from 0.6 mg L^?1 min^?1 to 5.13 mg L^?1 min^?1 depending on the process and on the sample. In the treatments combined with O₃, H₂O₂ dose utilized is 0.04 mM and TiO₂ dose, 1 g L^?1. In order to evaluate the influence of natural organic matter and suspension solids over the disinfection rate, treatments are performed with two types of water – natural water from Ebro River (Zaragoza, Spain) and NaCl solution 0.9%. To achieve 4 log units of inactivation, 3.6 mg O₃ L^?1 is necessary in O₃ treatment, 4.25 mg O₃ L^?1 in O₃/TiO₂ system and 2.7 mg O₃ L^?1 in O₃/H₂O₂ after processing the natural water. In NaCl solution, to get the same inactivation, 0.42 mg O₃ L^?1 is necessary in O₃ treatment, 1.15 mg O₃ L^?1 in O₃/TiO₂ system and 0.06 mg O₃ L^?1 in O₃/H₂O₂ process. Even though the three treatments studied have a high bactericidal activity due to the number of surviving bacteria decreases to non-detectable levels, O₃/H₂O₂ is the most effective system for eliminating C. perfringens cells in a lower contact time, followed by O₃ and finally O₃/TiO₂ system.     

O3/UV,O3/TiO2/UV,O3/VO2/TiO2降解磺基水杨酸

实验利用O3/UV,O3/TiO2/UV,O3/VO2/TiO2降解了磺基水杨酸.结果表明,在这三种高级氧化技术中,O3/VO2/TiO2的氧化效果最好,如在相同的条件下,30 min后取样表明三者COD的去除率分别为47%,55%和70%.在不同pH条件下研究表明O3/TiO2/UV对水体pH的影响较为敏感.通过加入自由基猝灭剂研究表明三者产生羟基自由基的活性顺序是O3/VO2/TiO2＞O3/TiO2/UV＞O3/UV.     

Ethylene Hydrogenation over Pt/Ga2O3/Al2O3 Catalysts

The effects of gallia addition on the Pt dispersion and the activity for ethylene hydrogenation at 0 °C were studied for Pt-supported catalysts as a function of the reduction temperature (350, 450, and 550 °C). The catalysts contained 0.5 wt.% Pt and were prepared by successive incipient wetness impregnations with Ga(NO₃)₃ and H₂PtCl₆ aqueous solutions. CO and H₂ chemisorption data indicated that, the addition of small amount of Ga₂O₃ caused an increase of the Pt dispersion and a decrease of ethylene conversion. Both of them decreased appreciably when Ga₂O₃ addition was increased, particularly, for the case where β-Ga₂O₃ was used as a support. The increase in reduction temperature magnified the negative effects of the gallia addition on dispersion and activity, although the addition of small amount of gallia improved the resistance to metal sintering. Results were interpreted in terms of the presence of reduced Ga species, which can encapsulate Pt particles.     

Oxide/oxide composites in the system Cr2O3-Y2O3-Al2O3

Ceramic compacts in the systems Al₂O₃–Y₂O₃, Cr₂O₃–Y₂O₃ and Y₃(Cr_yAl_1-y)₅O₁₂ (Cr-doped YAG) were prepared by solid state reaction in calcined co-precipitated powder mixtures of appropriate compositions. Various solid-solution phases were formed, e.g. Y₃(Al_1-xCr_x)₅O₁₂, YAl_yCr_1-yO₃ and Al_2-xCr_xO₃. Composite materials in the pseudo-binary or ternary systems Al₂O₃–Y₃Al₅O₁₂, Cr₂O₃–Y₂O₃ and Y₃(Al_1–xCr_x)₅O₁₂–YAl_yCr_1–yO₃–(Al_zCr_1−z)₂O₃ were obtained by hot-pressing appropriate powder precursors at 1600–1650°C for 1 h. The microstructure of the prepared materials was studied in a scanning electron microscope with element analysis facilities. X-ray diffraction was used to reveal the phases present and their lattice parameters. The chemical compatibility of these phases was investigated. The results are discussed with a special emphasis on the solubility of Cr in the YAG structure, and on the compatibility relationship between Cr-doped YAG and its neighbouring phases. A gel-coating process for preparing Al₂O₃–YAG composites with tailored microstructures is also described.     

Decomposition of Carboxylic Acids in Water by O3, O3/H2O2, and O3/Catalyst

This paper studies the decomposition of formic, oxalic and maleic acids by O₃, O₃/catalyst, and O₃/H₂O₂. The catalytic effect of Co²⁺, Ni²⁺, Cu²⁺, Mn²⁺, Zn²⁺, Cr³⁺, and Fe²⁺ ions is investigated. The results showed that—Co²⁺ and Mn²⁺ have the highest catalytic activity for the decomposition of oxalic acid while the catalytic effect of the studied ions is insignificant on the rate of decomposition of formic acid. Maleic acid decomposes by ozone into formic acid and glyoxylic acid, which subsequently oxidizes to oxalic acid. Though the studied ions have no effect on the decomposition of maleic acid, they have a significant effect on the produced oxalic and glyoxylic acids. In the presence of Cu²⁺ ions glyoxylic acid is mainly transformed into formic acid and traces of oxalic acid. In such case, a complete decomposition of maleic acid and its degradation products is achieved within 45 min. The results also show that combining H₂O₂ with O₃ results in an increase in the rate of decomposition of oxalic acid. However, O₃/H₂O₂ system is less active than O₃/Co²⁺ or O₃/Mn²⁺.     

Propylene metathesis over Re2O7/Al2O3-B2O3 catalysts

A series of alumina aluminum borate (AAB) with various Al/B molar ratios were prepared by the coprecipitation method. The supported rhenium oxide catalysts with various contents of Re₂O₇ were also prepared by the impregnation method with perrhenic acid. The catalytic activity and stability of Re₂O₇/AAB catalysts for the reaction of propylene metathesis were tested in a fixed-bed microreactor. It was found that Re₂O₇/AAB is more active, stable and regenerable than Re₂O₇/Al₂O₃ for propylene metathesis. The optimum Al/B molar ratio was found to be in the range of 4–10.     

Ferroelectric Ceramics in the PbMg1/3Nb2/3O3-PbCd1/3Nb2/3O3 System

Solid solutions (1-x)PbMg_1/3Nb_2/3O₃ + xPbCd_1/3Nb_2/3O₃ with x = 0-0.30 are investigated with purpose to work out a capacitor ceramics with good dielectric properties and low sintering temperature. It is found that the perovskite phase forms at sintering near to 980°C and begins to decompose at higher temperatures. When x grows from 0 to 0.30, the Curie temperature linearly grows from -10°C to +25°C, the dielectric permittivity ε_m in the Curie point T_C decreases from 18000 to 6800 and the phase transition becomes more diffused. The dielectric permittivity at room temperature is rather high and the temperature stability is improved. The system is of interest, because it can serve as a base for working out some ceramic materials for capacitors with low sintering temperature, which needs of no special atmosphere at burning.     

Air plasma-sprayed Y2O3 coatings for Al2O3/Al2O3 ceramic matrix composites

Al₂O₃/Al₂O₃ ceramic matrix composites (CMC) are candidate materials for hot-gas leading components of gas turbines. Since Al₂O₃/Al₂O₃ CMC are prone to hot-corrosion in combustion environments, the development of environmental barrier coatings (EBC) is mandatory. Owing to its favorable chemical stability and thermal properties, Y₂O₃ is considered a candidate EBC material for Al₂O₃/Al₂O₃ CMC. Up to 1 mm thick Y₂O₃ coatings were deposited by means of air plasma spraying (APS) on Al₂O₃/Al₂O₃ CMC with a reaction-bonded Al₂O₃ bond-coat (RBAO). APS Y₂O₃ coatings exhibit a good adherence in the as-deposited state as well as upon isothermal annealing up to 1400 °C. Moreover, furnace cyclic testing performed at 1200 °C revealed an excellent durability. This is explained by the formation of a continuous, approximately 1 μm thick reaction zone at the APS Y₂O₃/RBAO interface. The reaction zone between Y₂O₃ and Al₂O₃ comprises three layers of thermodynamically stable yttrium-aluminates exhibiting strong bonding, respectively.     

Broadband dielectric spectroscopy of PbMg1/3Nb2/3O3–PbSc1/2Nb1/2O3 ceramics

Broadband dielectric spectroscopy results of various ordered and disordered (1 ? x)Pb(Mg_1/3Nb_2/3)O₃–(x)Pb(Sc_1/2Nb_1/2)O₃ (PMN–PSN) ceramics are investigated in the temperature range from 80 K to 300 K and frequency range from 20 Hz to 2 THz. Dielectric dispersion is very broad and in the ferroelectrics case (x = 1, 0.95) consists of two parts: low-frequency part caused by ferroelectric domains and higher frequency part caused by soft mode. The relaxational soft mode exhibits pronounced softening close to phase transition temperature, as it is typical for order–disorder phase transitions. By substituting Sc³⁺ by Mg²⁺ in PMN–PSN ceramics relaxation slows down, and for relaxors (x = 0.2) the most probable relaxation frequency decreases on cooling according to Vogel–Fulcher law.