AlCl3·6H2O在FeCl3-CaCl2-HCl-H2O体系中溶解度的模拟和测定

在25~60 ℃的条件下,采用静态法测定了AlCl₃·6H₂O在FeCl₃-CaCl₂-HCl-H₂O体系中的溶解度。同时以OLI软件为平台,采用Bromley-Zemaitis活度系数模型预测了该温度范围内AlCl₃·6H₂O在FeCl₃-CaCl₂-HCl-H₂O体系中的溶解度,并将实验和预测结果做了对比。结果表明,在FeCl₃-HCl-H₂O和CaCl₂-HCl-H₂O这2个体系中,温度对AlCl₃·6H₂O溶解度的影响均可忽略;在相同温度和盐酸浓度下,随着FeCl₃和CaCl₂浓度的增大,AlCl₃·6H₂O的溶解度均减小;在相同温度、相同FeCl₃和CaCl₂浓度下,盐酸浓度对AlCl₃·6H₂O在2个体系中溶解度的影响均显著,随着盐酸浓度的增大,AlCl₃·6H₂O的溶解度急剧减小。比较后发现,实验数据和模型预测值吻合良好。     

三元体系AlCl3+CaCl2+H2O，AlCl3+FeCl3+H2O和CaCl2+FeCl3+H2O在35℃时的相平衡

缺少含AlCl₃、CaCl₂和FeCl₃的溶液相平衡,使通过蒸发结晶从粉煤灰盐酸浸取液中制备纯净的AlCl₃·6H₂O变得比较困难。采用等温溶解法研究了三元体系AlCl₃+CaCl₂+H₂O,AlCl₃+FeCl₃+H₂O和CaCl₂+FeCl₃+H₂O在35℃时的相平衡关系,测定了相应的溶解度及密度,并绘制了相应相图及密度-组成图。实验结果表明：三元体系AlCl₃+CaCl₂+H₂O和AlCl₃+FeCl₃+H₂O分别有两条溶解度曲线,两个单盐结晶区,无复盐和共溶体产生,同离子效应导致增加溶液中CaCl₂和FeCl₃浓度会有效降低AlCl₃的溶解度;CaCl₂+FeCl₃+H₂O体系会形成复盐CaCl₂·2FeCl₃·7H₂O;所得35℃相图与25℃相图相比,三元体系AlCl₃+CaCl₂+H₂O和AlCl₃+FeCl₃+H₂O中AlCl₃·6H₂O结晶区增大,CaCl₂·6H₂O结晶区转变成CaCl₂·4H₂O结晶区,CaCl₂+FeCl₃+H₂O体系中CaCl₂·2FeCl₃·8H₂O结晶区转变为CaCl₂·2FeCl₃·7H₂O结晶区。     

化学镀镍-钨-磷非晶态合金的研究

以电阻率为性能指标,采用正交试验对化学镀 Ni-W-P 的镀液配方进行优化,得到最优配方与工艺为:NiSO₄·6H₂O 15g/L,NaH₂PO₂·H₂O 25g/L,Na₂WO₄·2H₂O 10 g/L,Na₃C₆H₅O₇·2H₂O60 g/L,C₃H₆O₃5 mL/L,NH₄Cl 30g/L,pH = 9,温度 88℃,时间 2 h。采用扫描电镜、X 射线衍射仪、显微硬度计等研究了Ni-W-P 合金镀层的表面形貌、结构、显微硬度等性能。在最佳配方与工艺下,化学镀 Ni-W-P 的镀速为 6.9 μm/h,所得Ni-W-P 合金镀层的电阻率为 204.7 mΩ·cm,为典型的非晶态结构,表面均匀分布着大小不一、致密的胞状结构,镀层与基体之间结合力牢固,显微硬度高于 Ni-P 镀层,耐磨性和耐蚀性均优于 Ni-P 镀层。     

耐高温聚酰亚胺类胶粘剂制备及性能分析

为了分析影响耐高温聚酰亚胺类胶粘剂性能的因素,使用C₁₂H₁₂N₂O和C₂₇H₂₆N₂O₂作为二胺单体,C₁₇H₆O₇作为二酐单体,通过封端剂C₄H₂O₃和反应溶剂C₅H₉NO的共同作用制备了一种聚酰亚胺胶粘剂,测试了不同因素对胶粘剂粘接性能的影响。结果表明,固体质量分数、粘结件表面粗糙度、C₁₂H₁₂N₂O和C₂₇H₂₆N₂O₂单体的摩尔比、二酐与二胺单体的摩尔比、聚酰胺酸固化工艺、亚胺化程度和亚胺化方式都会对耐高温聚酰亚胺类胶粘剂的性能产生影响。当胶粘剂固体质量分数为30%、表面粗糙度的打磨砂纸型号为600...     

BN/Fe复合材料的制备及光催化性能研究

以C₃H₆N₆·2H₃BO₃为前驱体和纳米Fe₂O₃粉末为原料，通过热处理制备了一种BN/Fe复合材料。通过X射线衍射分析，扫描电子显微镜、透射电子显微镜、漫反射光谱等对合成的BN/Fe光催化剂进行表征，研究了其相组成、微结构和光催化性能。Fe₂O₃粉末在热处理下被还原为Fe纳米颗粒，合成了多孔结构的BN/Fe复合材料。在可见光照射下B4材料对MO的光降解活性最好，45 min内可快速降解99.3%的MO。     

Na2S2O3·5H2O复合材料的制备及循环稳定性能

为了解决Na₂S₂O₃·5H₂O存在的过冷度过大导致不结晶的问题,提高复合相变材料的循环稳定性并抑制相分离现象,以CaSO₄和1-萘酚（C₁₀H₈O）为成核剂;聚丙烯酸钠（PAAS）和羧甲基纤维素钠（CMC）为增稠剂进行改良,通过步冷曲线和差示扫描量热法（DSC）对复合相变材料进行了研究。实验结果表明：加入质量分数为1%和5%的CaSO₄、0.5%和3%的C₁₀H₈O对Na₂S₂O₃·5H₂O有较好的成核作用。萘酚体系在加入增稠剂后降温冷却时不出现结晶现象。对于CaSO₄体系,增稠剂PAAS效果优于CMC,Na₂S₂O₃·5H₂O+1%CaSO₄+2%PAAS复合材料相变温度47.7℃,相变潜热为200.4J/g;Na₂S₂O₃·5H₂O+5%CaSO₄+2%PAAS复合材料相变温度48.2℃,相变潜热为213.4J/g;经过100次高低温循环后,1%CaSO₄的复合材料相变温度47.6℃,相变潜热为192.4J/g,相较循环前相变潜热降低了3.99%。5%CaSO₄的复合材料相变温度47.8℃,相变潜热211.2J/g,相比循环前下降1.03%。5% CaSO₄体系较优于1% CaSO₄体系,循环前后潜热值、相变温度变化不大,循环稳定性良好。     

四元体系CaCl2-CaSO4-CaB6O10-H2O 308.15 K相平衡研究

采用等温溶解平衡法研究了四元体系CaCl₂-CaSO₄-CaB₆O₁₀-H₂O在308.15 K下的稳定相平衡。测定了该体系的溶解度及平衡溶液的物化性质(包括折射率、密度和pH)。根据实验数据，分别绘制了该四元体系的干基图、水图以及相应的物化性质–组成图。研究结果表明：该体系在308.15 K时有1个共饱点(CaCl₂·4H₂O + CaSO₄·2H₂O + CaB₆O₁₀·5H₂O)，3条单变量溶解度曲线，3个单盐结晶区,分别对应于CaCl₂·4H₂O、硬石膏(CaSO₄·2H₂O)和高硼钙石(CaB₆O₁₀·5H₂O)。其中，硬石膏CaSO₄·2H₂O结晶区最大、高硼钙石CaB₆O₁₀·5H₂O结晶区次之，而CaCl₂·4H₂O结晶区最小，表明硬石膏最易于结晶析出。此外，该四元体系在308.15 K下没有复盐和固溶体生成，属于简单水合物I型。平衡液相的物化性质随着CaCl₂浓度的增大呈规律性变化，并在共饱点处发生转折。其中，折射率和密度的变化规律相近，而pH的变化规律则与之相反。对该四元体系的稳定相平衡进行研究，将为综合开发利用油田卤水中的钙、硼等资源提供理论依据。     

碳纸负载铅电极的制备及其催化顺丁烯二酸电还原合成丁二酸

通过一步电沉积法制备CP@Pb电极,并将其用于催化顺丁烯二酸（C₄H₄O₄）电还原反应合成丁二酸（C₄H₆O₄）。利用SEM、TEM、XRD等手段对CP@Pb电极表面结构、物相组成等进行表征,通过CV及CP等方法研究CP@Pb电极在酸性环境中对C₄H₄O₄的电还原催化行为。结果表明,CP@Pb电极对C₄H₄O₄电还原具有良好的催化性能;反应温度为318.15 K时,在0.25 mol/L H₂SO₄+0.30 mol/L C₄H₄O₄中还原电流密度达到191.3 mA/cm²（-1 V）;当还原电流密度为120 mA/cm²时,合成丁二酸的纯度为96%。     

四元体系硼酸锂-硼酸钾-硼酸镁-水在308.15 K时固液相平衡研究

采用等温溶解平衡法研究四元体系硼酸锂-硼酸钾-硼酸镁-水在308.15 K时固液相平衡,测定了体系溶解度和平衡液相的密度、折光率和pH。研究发现：该体系308.15 K时的稳定相图中包含一个共饱点（L+Li₂B₄O₇·3H₂O+K₂B₄O₇·4H₂O+Mg₂B₆O₁₁·15H₂O）,其液相组成：w（Li₂B₄O₇）=3.112%、w（K₂B₄O₇）=16.64%、w（Mg₂B₆O₁₁）=0.101 8%;3个固相结晶区：Li₂B₄O₇·3H₂O、K₂B₄O₇·4H₂O、Mg₂B₆O₁₁·15H₂O,体系无复盐或固溶体生成。溶液中硼酸锂、硼酸钾对多水硼镁石有很强的盐析效应,液相的密度、折光率和pH随溶液中硼酸盐浓度的增加呈规律性变化。     

改性生物质炭负载铁类Fenton体系降解亚甲基蓝研究

以棉花秸秆作为前驱体,用K₂CO₃活化后制备出改性生物质炭K₂CO₃@BC,置于FeSO₄溶液中形成悬浮液,干燥并煅烧,制得改性生物质炭负载铁催化剂Fe/K₂CO₃@BC。采用XRD、FT-IR、SEM等对Fe/K₂CO₃@BC进行表征,并研究其耐酸耐碱性。以亚甲基蓝作为目标污染物,将Fe/K₂CO₃@BC催化剂和H₂O₂组成非均相类Fenton体系降解水中的亚甲基蓝,探究了溶液pH、Fe/K₂CO₃@BC投加量、H₂O₂用量、温度等因素对亚甲基蓝降解效果的影响。结果表明,催化剂Fe/K₂CO₃@BC中的Fe物种主要以Fe₃O₄形式...     

Enhanced activity of metal oxide-doped Ga2O3–Al2O3 for NO reduction by propene

Effect of additives, In₂O₃, SnO₂, CoO, CuO and Ag, on the catalytic performance of Ga₂O₃–Al₂O₃ prepared by sol–gel method for the selective reduction of NO with propene in the presence of oxygen was studied. As for the reaction in the absence of H₂O, CoO, CuO and Ag showed good additive effect. When H₂O was added to the reaction gas, the activity of CoO-, CuO- and Ag-doped Ga₂O₃–Al₂O₃ was depressed considerably, while an intensifying effect of H₂O was observed for In₂O₃- and SnO₂-doped Ga₂O₃–Al₂O₃. Of several metal oxide additives, In₂O₃-doped Ga₂O₃–Al₂O₃ showed the highest activity for NO reduction by propene in the presence of H₂O. Kinetic studies on NO reduction over In₂O₃–Ga₂O₃–Al₂O₃ revealed that the rate-determining step in the absence of H₂O is the reaction of NO₂ formed on Ga₂O₃–Al₂O₃ with C₃H₆-derived species, whereas that in the presence of H₂O is the formation of C₃H₆-derived species. We presumed the reason for the promotional effect of H₂O as follows: the rate for the formation of C₃H₆-derived species in the presence of H₂O is sufficiently fast compared with that for the reaction of NO₂ with C₃H₆-derived species in the absence of H₂O. Although the retarding effect of SO₂ on the activity was observed for all of the catalysts, SnO₂–Ga₂O₃–Al₂O₃ showed still relatively high activity in the lower temperature region.     

Catalytic reduction of SO2 over supported transition-metal oxide catalysts with C2H4 as a reducing agent

This work investigates performances of supported transition-metal oxide catalysts for the catalytic reduction of SO₂ with C₂H₄ as a reducing agent. Experimental results indicate that the active species, the support, the feed ratio of C₂H₄/SO₂, and pretreatment are all important factors affecting catalyst activity. Fe₂O₃/γ-Al₂O₃ was found to be the most active catalyst among six γ-Al₂O₃-supported metal oxide catalysts tested. With Fe₂O₃ as the active species, of the supports tested, CeO₂ is the most suitable one. Using this Fe₂O₃/CeO₂ catalyst, we found that the optimal Fe content is 10 wt.%, the optimal feed ratio of C₂H₄/SO₂ is 1:1, and the catalyst presulfidized by H₂+H₂S exhibits a higher performance than those pretreated with H₂ or He. Although the feed concentrations of C₂H₄:SO₂ being 3000:3000 ppm provide a higher conversion of SO₂, the sulfur yield decreases drastically at temperatures above 300 °C. With higher feed concentrations, maximum yield appears at higher temperatures. The C₂H₄ temperature-programmed desorption (C₂H₄-TPD) and SO₂-TPD desorption patterns illustrate that Fe₂O₃/CeO₂ can adsorb and desorb C₂H₄ and SO₂ more easily than can Fe₂O₃/γ-Al₂O₃. Moreover, the SO₂-TPD patterns further show that Fe₂O₃/γ-Al₂O₃ is more seriously inhibited by SO₂. These findings may properly explain why Fe₂O₃/CeO₂ has a higher activity for the reduction of SO₂.     

撞击流反应器制备纳米四氧化三铁的研究

在浸没式循环撞击流反应器中,以氨水为沉淀剂,用七水合硫酸亚铁和六水合三氯化铁为原料,采用共沉淀法制备了纳米四氧化三铁粒子。考察了搅拌转速、亚铁与三价铁物质的量比、反应温度和溶液pH对所得纳米四氧化三铁的分散性和粒径的影响。采用傅里叶红外光谱仪、透射电镜、X射线衍射仪等对制得的纳米粒子的结构和性能进行了表征。结果表明：用撞击流反应器制备纳米四氧化三铁粒子的最佳工艺条件：亚铁与三价铁物质的量比为1 ∶1,反应温度为40 ℃,搅拌转速为1 600 r/min,以氨水作沉淀剂,最佳pH控制在11.0左右。在上述条件下,可以制备出分散性好、纯度高、平均粒径为10 nm的四氧化三铁粒子。     

L-精氨酸衍生物的合成及其性质研究

以L-精氨酸(L-Arginine)和香兰素(Vanillin)为原料,首先合成新型的具有手性的希夫碱配体L(C_(14)H_(14)KN_3O_4),其次配体L分别与金属盐(CH_3COO)_2Ni·2H_2O、BaCl_2、(CH_3COO)_2Zn·2H_2O进行配位反应,得到3种新型的金属配合物(C_(16)H_(19)ZnKN_3O_7、C_(14)H_(14)BaClKN_3O_4和C_(18)H_(20)KN_3NiO_8),目标产物用IR、荧光分光光度计和元素分析仪等表征其结构,并用紫外漫反射光谱在可见光照射下,考察了配体L和3种新型的金属配位化合物的催化性能。实验结果推测配体L和L金属配合物均具有光催化性质,L金属配合物的催化性能更强。     

Water vapor sensitivity of nanosized La(Co, Mn, Fe)1−x(Cu, Pd)xO3 perovskites during NO reduction by C3H6 in the presence of oxygen

A series of La(Co, Mn, Fe)_1−x(Cu, Pd)_xO₃ perovskites having high specific surface areas and nanosized crystal domains was prepared by reactive grinding. The solids were characterized by N₂ adsorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature programmed desorption (TPD) of O₂, NO + O₂, C₃H₆, in the absence or presence of 5% H₂O, Fourier transform infrared (FTIR) spectroscopy, as well as activity tests towards NO reduction by propene under the conditions of 3000 ppm NO, 3000 ppm C₃H₆, 1% O₂, 0 or 10% H₂O, and 50,000 h⁻¹ space velocity. The objective was to investigate the influence of H₂O addition on catalytic behavior. A good performance (100% NO conversion, 77% N₂ yield, and 90% C₃H₆ conversion) was achieved at 600 °C over LaFe_0.8Cu_0.2O₃ under a dry feed stream. With the exposure of LaFe_0.8Cu_0.2O₃ to a humid atmosphere containing 10% water vapor, the catalytic activity was slightly decreased yielding 91% NO conversion, 51% N₂ yield, and 86% C₃H₆ conversion. A competitive adsorption between H₂O vapor with O₂ and NO molecules at anion vacancies over LaFe_0.8Cu_0.2O₃ was found by means of TPD studies here. A deactivation mechanism was therefore proposed involving the occupation of available active sites by water vapor, resulting in an inhibition of catalytic activity in C₃H₆ + NO + O₂ reaction. This H₂O deactivation was also verified to be strictly reversible by removing steam from the feed.     

Catalytic reduction of NO by propene over LaCo1−xCuxO3 perovskites synthesized by reactive grinding

One series of LaCo_1−xCu_xO₃ perovskites with high specific surface area was prepared by the new method designated as reactive grinding. These solids were characterized by N₂ adsorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), H₂-temperature programmed reduction (TPR), O₂-temperature programmed desorption (TPD), NO + O₂-TPD, C₃H₆-TPD, NO + O₂-temperature programmed surface reaction (TPSR) under C₃H₆/He flow as well as catalytic reduction of NO activity tests. The catalytic performance of unsubstituted sample is poor with a maximum conversion to N₂ of 19% at 500 °C at a space velocity of 55,000 h⁻¹ (3000 ppm NO, 3000 ppm C₃H₆, 1% O₂ in helium) but it is improved by incorporation of Cu into the lattice. A maximal N₂ yield of 46% was observed over LaCo_0.8Cu_0.2O₃ under the same conditions. Not only the abundance of -oxygen but also the mobility of β-oxygen of lanthanum cobaltite was remarkably enhanced by Cu substitution according to O₂-TPD and H₂-TPR studies. The better performance of Cu-substituted samples is likely to correspond to the essential nature of Cu and facility to form nitrate species in NO transformation conditions. In the absence of O₂, the reduction of NO by C₃H₆ was performed over LaCo_0.8Cu_0.2O₃, leading to a maximal conversion to N₂ of 73% accompanied with the appearance of some organo nitrogen compounds (identified as mainly C₃H₇NO₂). Subsequently, a mechanism involving the formation of an organic nitro intermediate, which further converts into N₂, CO₂ and H₂O via isocyanate, was proposed. Gaseous oxygen acts rather as an inhibitor in the reaction of NO and C₃H₆ over highly oxidative LaCo_0.8Cu_0.2O₃ due to the heavily unselective combustion of C₃H₆ by O₂.     

Effect of hydrogen on reaction intermediates in the selective catalytic reduction of NOx by C3H6

Selective catalytic reduction of NO_x by C₃H₆ in the presence of H₂ over Ag/Al₂O₃ was investigated using in situ DRIFTS and GC–MS measurements. The addition of H₂ promoted the partial oxidation of C₃H₆ to enolic species, the formation of –NCO and the reactions of enolic species and –NCO with NO_x on Ag/Al₂O₃ surface at low temperatures. Based on the results, we proposed reaction mechanism to explain the promotional effect of H₂ on the SCR of NO_x by C₃H₆ over Ag/Al₂O₃ catalyst.