H2O2处理H3PW12O40/ZrO2-WO3光催化降解有机染料

采用浸渍法将H3PW12O40负载在ZrO2-WO3上,通过H2O2溶液的敏化,制得H3PW12O40/ZrO2-WO3(x)光催化剂。然后以光降解甲基橙为探针反应,对各反应影响因素进行了探究。在甲基橙初始质量浓度为5 mg/L,溶液pH=2.5,催化剂用量为0.3 g的优化条件下,光降解2 h,甲基橙的降解率达到91.2%,光催化降解甲基橙溶液为一级动力学反应。且H3PW12O40/ZrO2-WO3(x)对罗丹明B、碱性品红和和亚甲基蓝也具有较高的光催化活性,降解率分别为70.0%、73.0%和73.5%。     

O3/H2O2协同氧化法预处理石化废水的实验研究

采用O3/H2O2法对含高浓度酚的石化废水进行了实验研究,对单独O3法和O3/H2O2法的处理效果进行了比较。结果表明:O3/H2O2法的处理效果优于单独O3法;在pH为10,反应时间为40 min,O3流量为4 g/h,H2O2投加量为30 mmol/L条件下,废水中的挥发酚和COD的去除率分别达到96.79%和76.78%,B/C由原来的0.067提高到0.380。     

O3/H2O2协同氧化法预处理石化废水的实验研究

采用O3/H2O2法对含高浓度酚的石化废水进行了实验研究,对单独O3法和O3/H2O2法的处理效果进行了比较。结果表明:O3/H2O2法的处理效果优于单独O3法;在pH为10,反应时间为40 min,O3流量为4 g/h,H2O2投加量为30 mmol/L条件下,废水中的挥发酚和COD的去除率分别达到96.79%和76.78%,B/C由原来的0.067提高到0.380。     

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。     

SiO2载体对Cu/SiO2催化剂的影响

分别以硅溶胶、气相SiO2、介孔SBA-15分子筛为载体,采用共沉淀法制备了Cu/SiO2催化剂,含活性组分Cu质量分数为25%。运用BET、XRD、H2-TPR、NH3-TPD等对催化剂进行表征。结果表明:以硅溶胶和气相SiO2为载体制得催化剂的Cu物种分散性较差,以SBA-15为载体制得催化剂的Cu物种以高度分散的形式存在,且具有较大的比表面积,较低的还原温度和较大的酸量。     

WO3/TiO2催化剂活性组分W对SO2的氧化特性

采用超声浸渍法制备了不同W负载量的WO₃/TiO₂催化剂,研究了W负载量、温度及SO₂浓度对催化剂表面SO₂氧化过程的影响。结果表明,催化剂表面SO₂氧化率随W负载量及温度的升高而增大,当W负载量由1%增至7%时,SO₂氧化率由0.034%升高至0.210%;而当温度由280℃升高至400℃时,SO₂氧化率由0.043%升高至0.240%。通过N₂吸附、XRD、Raman、NH₃-TPD、H₂-TPR及XPS等方法对催化剂样品进行表征。结果表明,活性组分W的增加会导致WO_x增加,该结构能够减弱催化剂表面Br?nsted酸性位点强度,增强SO₂在催化剂表面的吸附,同时导致催化剂表面吸附氧(O_α)增多,促进SO₂氧化;针对W负载量5%的催化剂原位红外试验结果表明,通入SO₂     

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/TiO2-SiO2光催化降解甲基红

采用溶胶-凝胶法制备TiO₂-SiO₂,用浸渍法将H₂PW₁₂O₄₀负载在TiO₂-SiO₂上,制得H₃PW₁₂O₄₀/TiO₂-SiO₂光催化剂。探究在模拟自然光条件下,光照时间、甲基红溶液初始浓度、催化剂用量和溶液pH对甲基红可见光催化降解的的影响。实验结果显示,在光照时间为15min.甲基红溶液初始浓度为15mg/L.催化剂用量为1.8g/L以及pH为2的优化条件下,甲基红的光降解率高达99.7%。光催化降解甲基红溶液为一级动力学反应。     

TiO2对二相Al2O3-SiO2胶体形成莫来石陶瓷的影响

二相Al2O3-SiO2胶体是由无机盐水溶液遵循胶化反应通过溶胶-凝胶法合成的。研究了TiO2添加剂对由二相胶体合成莫来石陶瓷的影响。对先驱体二相胶体粉末进行了化学分析,发现在添加剂存在的情况下莫来石晶体的形态变化显著。含3%添加剂的试样中有高于15%的莫来石形成。通过添加TiO2,最大程度地降低了显气孔率,并且提高了烧结致密体的体积密度。在TiO2添加剂最优化的情况下,烧结致密体的抗折强度和断裂韧性分别提高了26%和9%。     

313.15 K下三元体系KH2PO4-(NH2)2CO-H2O相平衡研究

采用等温溶解平衡法研究了三元体系KH₂PO₄-(NH₂)₂CO-H₂O在313.15 K下的溶解度数据,根据溶解度数据绘制了等温相图,采用湿渣法和X射线衍射法对平衡固相的组成进行了分析。结果表明三元体系KH₂PO₄-(NH₂)₂CO-H₂O为简单共饱和型体系,相图中有1个共饱和点、2条单变量曲线、3个结晶区;采用Wilson和NRTL模型关联该体系的溶解度数据,关联计算值与实验值基本吻合。其中Wilson模型的相对平均偏差(RAD)和均方根差(RMSD)分别为3.34%、0.17%;NRTL模型的RAD和RMSD分别为10.53%、0.38%。对比三元体系KH₂PO₄-(NH₂)₂CO-H₂O在多个温度下相平衡的结晶区域,发现在中、低温阶段降低温度有利于尿素[(...     

SUSTAINED UO2 MELTS USING THE INDUCTIVE RING SUSCEPTOR TECHNIQUE†

A method for melting and sustaining large volumes of UO₂ has been developed. The method, known as the Inductive Ring Susceptor Technique, melts UO₂ powder via inductively heated refractory metal rings. The technique has been fully demonstrated by a series of experiments which melted 5-5 kg charges of powdered SiO₂, AI₂O₃,and UO₂     

Microstructure of rapidly-quenched ZrO2-SiO2 glass-ceramics fabricated by container-less aerodynamic levitation technology

In this work, an aerodynamic levitation technology (ALT) was utilized to prepare ZrO₂-SiO₂ glass-ceramics with two different ZrO₂ contents, that is, 35 mol% and 50 mol%. The glass-ceramics were partially melted at ∼2000°C or fully melted at ∼3000°C by ALT, followed by rapid quenching to obtain spherical glass-ceramic beads. The phase compositions and microstructures of the glass-ceramics were characterized. Crystallization of ZrO₂ occurred during the solidification process and ZrO₂ content, processing temperature, and the addition of yttrium (3 mol%) affected the crystalline phase of ZrO₂. No ZrSiO₄ or crystalline SiO₂ were formed during the solidification process and the glass-ceramics were away from thermodynamic equilibrium due to rapid quenching. The glass-ceramics showed a microstructure of irregular-shaped ZrO₂ micro-aggregates embedded in an amorphous SiO₂ matrix, with lamellar twins and lattice defects formed within ZrO₂ crystals. For samples prepared at ∼3000°C, a liquid-liquid phase separation occurred in the melt, which eventually resulted in the formation of large and irregular-shaped ZrO₂ aggregates. In comparison, for samples prepared at ∼2000°C, pre-existed ZrO₂ crystals formed during heating acted as nucleation sites during the cooling process, followed by grain growth to form large ZrO₂ aggregates. Solidification and microstructure formation mechanisms were proposed to elucidate the solidification process during rapid cooling and the microstructure of the glass-ceramics obtained.     

SUSTAINED UO2 MELTS USING THE INDUCTIVE RING SUSCEPTOR TECHNIQUE†

A method for melting and sustaining large volumes of UO₂ has been developed. The method, known as the Inductive Ring Susceptor Technique, melts UO₂ powder via inductively heated refractory metal rings. The technique has been fully demonstrated by a series of experiments which melted 5-5 kg charges of powdered SiO₂, AI₂O₃,and UO₂     

Microstructure of seal formed between a Nb wire and an Al2O3 capillary melted by YAG laser radiation

Cracks occasionally develop inside the glass frit, the sealing material used in ceramic metal-halide lamps that employ polycrystalline alumina as the arc-tube material, although the rate at which these cracks develop is low. Therefore, we proposed a new method to stop their development. Our method did not make use of a glass frit and involved the formation of a seal between the Nb wire and the Al₂O₃ capillary melted by the radiant energy from a YAG laser. However, cracks or voids developed inside the melted Al₂O₃ capillary. Therefore, in order to control the Al₂O₃ microstructure inside the melted Al₂O₃ capillary and thus to obtain a better seal, grain growth was suppressed by combining the processes of annealing after melting and grain-boundary deposition of Ta. The Al₂O₃ microstructure could be controlled by these factors. Thus, optimized conditions for forming the seal were achieved.     

Preparation of novel TiP2O7 carbon composite using ion-exchanged resin (C467) and evaluation for photocatalytic decomposition of 2-propanol

TiP₂O₇ carbon composite photocatalyst was successfully prepared by using ion-exchanged resin (C467) containing amino phosphate by metal ion-exchanged carbothermal reduction (MIER-CTR) method using TiCl₃ and TiCl₄. During the carbonization process in nitrogen, the pre-oxidation (300–350 °C) in air is essential for producing homogeneously dispersed TiP₂O₇ on the carbon matrix. In the absence of pre-oxidation, the resin was melted. The carbonization temperature 500 °C was found to be suitable for producing single phase TiP₂O₇ with higher yields. Powder X-ray diffraction (XRD) and Raman spectroscopic results suggest the formation of TiP₂O₇, while X-ray diffraction results reveal that the crystallite size was less than 35 nm. UV-Vis studies show that the band gap of TiP₂O₇ was 3.32 eV. The TiP₂O₇ carbon composite catalyst was applied for the photocatalytic decomposition of 2-propanol at 30 °C using a mercury lamp (365 nm).     

The System UO2-ZrO2

A phase diagram is proposed for the system UO₂-ZrO₂ on the basis of earlier work and the results of new studies in which the mixed oxides were melted in a solar furnace to avoid contamination. X-ray diffraction measurements were made on specimens melted in helium and on the same specimens after heating to 1350°C. in helium. The system shows a narrow two-phase region about the eutectic at high temperatures which increases in extent at lower temperatures. The high-temperature form of zirconia cannot be stabilized by the addition of UO₂.     

超细ZrO_2中锆的测定

根据经高温灼烧制得的超细氧化锆的性质,作者经研究试验,以NaOH固体作熔剂,在银坩埚中熔化分解,水浸取、酸化、微热即得澄清的试样溶液,可用EDTA配位滴定法准确测定锆含量。从而发现了一种新的分解ZrO_2的方法。该方法稳定可靠,易掌握。     

含钛高炉渣制备二氧化钛晶须的研究

以承德钢铁公司含钛高炉渣以及石英、硼酸、硼砂为主要原料,将配料组成选择在Na₂O-CaO-Al₂O₃-B₂O₃-SiO₂-TiO₂系的分相区域,其中炉渣质量分数为50%~72%。将混合均匀的配料在1 250 ℃高温厢式电阻炉中熔融制得玻璃样品,对玻璃样品在700~900 ℃进行热处理制备二氧化钛晶须。用X射线衍射（XRD）、扫描电镜（SEM）对样品进行物相和形貌分析,结果表明：热处理温度为850 ℃时析出直径为0.5~1 μm、长径比大于50的钛酸钙（CaTiO₃）晶须。样品组成中氧化钠的含量对钛酸钙晶须的生成影响较大,氧化钠的引入导致［BO₃］向［BO₄］转变,促进系统分相,使分相界面增多,提供了有利的成核位,促进了晶须的生长。样品的光催化效率最高可达58%。     

层间组装SiO2-TiO2粘土材料的制备与表征

以(C2H5O)4Si和Ti(OC4H9)4为硅源和钛源,采用溶胶-凝胶法制备SiO2-TiO2柱化剂,将原土直接加入柱化剂进行柱化反应得到SiO2-TiO2柱撑蒙脱土,对其进行结构和性能表征,考察了柱化剂中Si/Ti比、柱化剂/原土比、柱化反应条件(反应温度和超声处理)及热处理温度对其结构和性能的影响. 结果表明,SiO2-TiO2柱体成功进入蒙脱土层间,在除去未参与柱化反应的柱化剂的条件下,比表面积可达127.2 m2/g,热稳定性提高了70℃,柱化剂中Si含量增加有利于热稳定性的提高,500℃以下焙烧的SiO2-TiO2柱体中Ti以钛氧四面体和八面体形式存在,600℃焙烧可形成锐钛矿晶型.     

Formation of Y3Al5O12–Al2O3 eutectic microstructure with off-eutectic composition

Homogeneous-eutectic microstructure of Y₃Al₅O₁₂–Al₂O₃ system without coarse primary crystals was formed at an off-eutectic composition. This method utilizes a low migration rate in an amorphous phase. A mixture of Y₂O₃ and Al₂O₃ having the off-eutectic composition was melted and quenched rapidly to form an amorphous phase. A heat-treatment of the amorphous phase at 1000 °C and 1300 °C for 30 min formed Y₃Al₅O₁₂ and Al₂O₃ phases. SEM observation of this material, which was formed from the amorphous phase at 1300 °C for 30 min, showed homogeneous eutectic-like microstructure. The formation of the primary crystals (coarse Al₂O₃), which are always observed in the off-eutectic compositions by ordinary method, was completely suppressed.