铁酸钴活化过一硫酸盐处理高盐废水中罗丹明B的研究

采用溶胶-凝胶法制备了催化剂铁酸钴（CoFe₂O₄）纳米材料,借助扫描电子显微镜（SEM）和 X 射线衍射仪（XRD）对催化剂进行了表征。配制了质量浓度 10 g/L 硫酸钠,50 mg/L 的罗丹明模拟废水,开展了铁酸钴活化 PMS降解高盐废水中罗丹明 B（RhB）的实验。对比了单独投加 PMS、CoFe₂O₄和同时投加 PMS/CoFe₂O₄对 RhB 的降解效果,探究了 PMS投加量、CoFe₂O₄投加量、初始 pH、硫酸钠含量等因素对过一硫酸盐/铁酸钴（PMS/CoFe₂O₄）体系降解RhB 效果的影响。结果表明,PMS/CoFe₂O₄体系降解高盐废水中 RhB 效果显著;硫酸钠的存在对 RhB 的降解过程有一定的抑制作用;在PMS投加量0.8 mmol/L、CoFe₂O₄投...     

CoFe2O4@MS活化过一硫酸盐处理6-硝氧体废水的研究

采用溶胶-凝胶法制备了催化剂CoFe₂O₄@MS,对以其活化过一硫酸盐（PMS）处理重要染料中间体废水 6-硝氧体废水进行了研究。采用扫描电子显微镜（SEM）、X 射线衍射仪（XRD）和傅立叶变换红外吸收光谱仪（FTIR）对催化剂进行表征。系统研究了 PMS投量、催化剂投量、初始 pH 和反应温度对 CoFe₂O₄@MS/PMS 体系处理 6-硝氧体废水的影响。结果表明：CoFe₂O₄@MS/PMS 催化体系对 6-硝氧体废水 COD 降解效果显著;6-硝氧体废水 COD 降解率随 PMS 投量先增加后减少,随催化剂投量和温度的增加而增加;6-硝氧体废水 COD 降解在强酸性条件下效果最好,在强碱性条件下效果大幅降低。在实际废水处理时,选择 PMS投量 12 g/L、催化剂投量 0.5 g/L,在常温（25 ℃）下无需调 pH,反应 60 min 内对 6-硝氧体废水的 COD 降解率可达 99.84%。实验结果可为非均相过渡金属催化剂活化PMS 处理萘磺...     

ZIF-67衍生Co3O4/g-C3N4复合材料光催化降解盐酸四环素废水的研究

将ZIF-67与g-C₃N₄按一定质量比复合制备Co₃O₄/g-C₃N₄复合光催化材料,并以此来提高Co₃O₄的光催化性能。利用XRD、SEM和FT-IR对复合材料结构、性能和元素分布进行表征。结果表明,当盐酸四环素(TC-HCl)质量浓度为3 mg/L、质量分数为3%的Co₃O₄/g-C₃N₄投加量为15 mg且pH为中性时,催化剂光催化性能最佳,90 min降解盐酸四环素效率达到了91.1%。3%Co₃O₄/g-C₃N₄复合光催化剂重复使用5次后,其降解率仍可达到88.5%,表明该材料具有一定的光催化稳定性和重复利用性。体系自由基捕获实验证明,产生了·O^-₂、h⁺、·OH...     

Co3O4/HY选择性催化苯甲醇氧化合成苯甲醛的研究

以HY分子筛为载体,采用水热法合成了系列Co₃O₄/HY复合分子筛催化剂,通过XRD、SEM、EDS、FT-IR、BET等手段对Co₃O₄/HY进行表征,并对Co₃O₄/HY分子筛催化氧气液相氧化苯甲醇合成苯甲醛的性能进行研究。结果表明,Co₃O₄的引入未破坏分子筛的骨架结构,且Co₃O₄在HY晶体表面形成片层蜂窝状多孔结构,可有效增加催化剂样品的介孔孔容和外表面积,增加催化活性。但Co₃O₄负载过量易出现堆叠现象,使得介孔孔容和外表面积降低,不利于氧化反应进行。以1.0-Co₃O₄/HY为催化剂,在适宜的反应条件下苯甲醇的转化率和苯甲醛的选择性分别达到73.2%和95.8%;催化剂重复使用5次,依然表现出较好的催化活性。     

还原氧化石墨烯膜负载Co3O4活化过硫酸氢钾降解罗丹明B

以RGO(还原氧化石墨烯膜)为载体,采用水热法制备RGO/Co₃O₄高效复合催化剂。通过XRD(X射线衍射仪)、SEM(扫描电子显微镜)和XPS(X射线光电子能谱仪)等手段对复合催化剂的结构、形貌和化学组成等进行表征,并以RhB(罗丹明B)为降解物评价复合催化剂活化PMS(过硫酸氢钾)的反应活性。另外,考察了PMS质量浓度、RhB初始质量浓度、pH值及温度对催化剂活化PMS降解RhB的影响。结果表明：在PMS质量浓度为100 mg/L、RhB初始质量浓度为10 mg/L、pH值为7、温度为25℃时反应18 min对RhB降解率为98%。自由基捕获实验结合ESR(电子顺磁共振)结果表明体系中同时存在SO₄^-·和HO·2种活性自由基。循环实验结果显示催化剂经过5次循环使用后对RhB的降解率仍保持90%以上,显示优异的循环稳定性。     

Mn-Ti-Mg/Al2O3催化臭氧氧化处理煤化工废水

以浸渍法制备金属复合催化剂Mn-Ti-Mg/Al₂O₃，采用SEM-EDS、XPS、BET对复合催化剂的表观形貌、原子组成、金属元素的存在状态、比表面积和平均孔径进行表征，并测定了其pH_zpc。之后将其作为多相催化剂用于催化臭氧氧化处理煤化工废水，对其催化效果进行研究，考察了催化剂投加量、O₃流速、溶液初始pH对其催化效能的影响，并对其稳定性进行了研究。结果表明，Mn-Ti-Mg/Al₂O₃复合催化剂对于催化臭氧氧化处理煤化工废水效果较好，催化剂投加量和臭氧流速的增加有利于提高煤化工废水COD的去除率，废水在碱性条件下更易被处理。经过催化臭氧氧化处理之后，废水的pH显著降低，导致催化剂中金属活性成分溶出，催化剂活性降低。在温度22℃、溶液初始pH 7.8、催化剂投加质量浓度10 g/L、臭氧流速1.0 mg/min、反应时间40 min条件下，采用Mn-Ti-Mg/Al₂O₃催化臭氧氧化处理煤化工废水，处理后废水...     

硫修饰的多孔Co3O4活化过一硫酸盐降解亚甲基蓝

以Na₂S₂O₃为硫源，采用改进的草酸盐-热解法制备了一系列硫修饰的Co₃O₄多孔催化剂[S_x@Co₃O₄,x=0.25、0.50、0.75、1,x为硫的修饰量，以Co(NO₃)₂·6H₂O的物质的量为基准，下同]。以亚甲基蓝(MB)为降解模型，考察了不同催化剂活化过一硫酸盐(PMS)的性能。探讨了催化剂用量、PMS浓度、反应温度、常见阴离子种类在S_x@Co₃O₄-PMS体系下对MB降解率的影响，并评价了催化剂的循环稳定性。结果表明，随着硫修饰量的增加，Co₃O₄的催化性能逐渐升高，S₁@Co₃O₄表现出最佳的催化性能。硫元素以SO₄^2–     

Sr掺杂强化LaCo0.5Cu0.5O3型钙钛矿活化过一硫酸盐的性能

采用溶胶-凝胶法制备A位掺Sr的La_xSr_1-xCo_0.5Cu_0.5O₃钙钛矿增强传统B位掺杂钙钛矿活化过一硫酸盐（PMS）的能力。本文选取效果最好的La_0.7Sr_0.3Co_0.5Cu_0.5O₃型钙钛矿为研究对象，以偶氮染料AO7为目标污染物，考察了钙钛矿投加量、PMS浓度、pH和染料废水中常见Cl^-对La_0.7Sr_0.3Co_0.5Cu_0.5O₃/PMS体系降解AO7的影响，并测试了材料的重复利用性和矿化能力。结果表明，La_0.7Sr_0.3Co_0.5Cu_0.5O₃/PMS降解AO7的速度随着材料投加量和PMS浓度的增加而加快，在中性条件下反应速度最快且矿化率良好。该体系主要活性物种之一为·OH，但Sr掺杂后钙钛矿的O空位增多使得¹O₂也参与到降解过程之中。     

不同形貌氧化钴活化过一硫酸盐降解硝基酚

通过控制形貌制备具有高活性晶面的金属氧化物可提高硝基酚的降解效果，以硝酸钴和乙酸钴为原料，制备了八面体、立方块和棒状Co₃O₄，通过X射线衍射（XRD）、扫描电子显微镜（SEM）和透射电子显微镜（TEM）对催化剂进行表征，表明合成的Co₃O₄粒径均匀、纯度较高。以3种不同形貌的Co₃O₄为催化剂，在pH值为8.0条件下活化过一硫酸盐（PMS）降解不同种类的硝基酚，采用高效液相色谱和总有机碳分析仪测定反应前后硝基酚和总有机碳含量（TOC）变化。3种Co₃O₄在Co₃O₄/PMS体系降解硝基酚时表现出不同的催化活性：棒状Co₃O₄ > 立方块Co₃O₄ > 八面体Co₃O₄，并且对不同硝基酚的降解效率存在显著的差异性。3种Co₃O₄在pH值为8.0下活化PMS所析出的Co²⁺含量较低，且均表现出良好的循环利用性。自由基淬灭实验和电子自旋共振（ESR）测试表明Co₃O₄/PMS体系降解硝基酚是通过自由基和非自由基机制共同协作完成的，起作用的活性氧化物种主要为羟基自由基（·OH）、硫酸根自由基（SO₄^·-）和单线态氧（¹O₂）。     

钴强化铁磁体活化过一硫酸盐的实验研究

采用溶剂热法后高温煅烧的方式制备了铁钴双金属复合催化剂,用以活化过一硫酸盐(PMS)降解偶氮染料金橙Ⅱ(OGⅡ)。通过X射线衍射仪、扫描电子显微镜、振动样品磁强计和X射线光电子能谱仪等仪器对复合材料进行了表征。考察了钴复合量、不同去除体系、催化剂投加量、PMS投加量、污染物浓度、pH和共存阴离子等因素对OGⅡ降解效果的影响,并探究了铁钴复合催化剂重复利用的效果。实验结果表明,铁钴复合催化剂可以有效活化PMS降解OGⅡ,在n(Co₃O₄)∶n(Fe₂O₃)=0.1、催化剂投加量为1.0 g/L、PMS投加量为0.4 mmol/L、OGⅡ浓度为30 mg/L、溶液pH为6.2的条件下,反应60 min后,OGⅡ的降解率达到了95.81%,其降解过程符合准一级反应动力学模型,最大反应速率常数为0.0491 min^-1。复合催化剂使用4次后对OGⅡ仍有68.85%的降解率。·SO{}_{\mathrm{4}}^{-}、·OH和¹O₂是反应体系产生的活性氧物种,¹O₂在OGⅡ的降解中起主要作用。     

Electrical properties of niobium doped Bi4Ti3O12-SrBi4Ti4O15 intergrowth ferroelectrics

Nb-doped Bi₄Ti₃O₁₂-SrBi₄Ti₄O₁₅ intergrowth ceramics have been prepared by modified oxalate route. XRD phase analysis confirmed the formation of single phase compound. Nb-doping does not affect the basic crystal structure of the intergrowth. SEM micrographs showed that the grain size of the ceramics decreases with Nb-doping. The temperature dependence of dielectric constant and losses was investigated in the temperature range 30–800 °C and frequency range 1 kHz–1 MHz. With Nb-doping, the T_c of the ferroelectrics reduces and peak permittivity increases. Doping also introduces small relaxor behavior in the ferroelectrics. The dc conductivity of the ceramics decreases with doping. The remnant polarization (P_r) of the intergrowth ferroelectrics is increased with Nb doping.     

Phase Equilibria in the Systems UF4-ThF4 and Li F-UF4-ThF4

As part of a study of materials potentially useful as fluid fuels for high-temperature reactors, equilibrium diagrams for the condensed systems UF₄–ThF₄ and LiF-UF₄–ThF₄ have been determined. Both thermal analysis and quenching techniques were used with phase identification accomplished by microscopic and X-ray dsraction analyses. A complete series of solid solutions without maximum or minimum is formed by UF₄ and ThF₄. Within the system LiF-UF₄–ThF, there occur three invariant points and seven primary phases of which four are ternary solid solutions. Optical properties for all the solid solutions, fractionation paths for the ternary solid solutions, and compatibility triangles for the ternary invariant points have been determined.     

Synthesis of Al4SiC4

The conditions necessary for synthesizing Al₄SiC₄ from mixtures of aluminum, silicon, and carbon and kaolin, aluminum, and carbon, as starting materials, were examined in the present study. The standard Gibbs energy of formation for the thermodynamic reaction SiC( s ) + Al₄C₃( s ) = Al₄SiC₄( s ) changed from positive to negative at 1106°C. SiC and Al₄C₃ formed as intermediate products when the mixture of aluminum, silicon, and carbon was heated in argon gas, and Al₄SiC₄ then formed by reaction of the SiC and Al₄C₃ at >1200°C. Al₄C₃, SiO₂, Al₂O₃, SiC, and Al₄O₄C formed as intermediate products when the mixture of kaolin, aluminum, and carbon was heated under vacuum, and Al₄SiC₄ formed from a reaction of those intermediate products at >1600°C.     

Laser surface nanostructuring for reliable Si3N4/Si3N4 and Si3N4/Invar joined components

IR pulsed laser radiation in air was applied to Si₃N₄ and Invar to obtain reliable Si₃N₄/Si₃N₄ and Si₃N₄/Invar adhesive bonded components. The laser pre-treatment produced a homogeneous nanostructured oxide layer on the surfaces, which effectively increased the adhesion at the adhesive/adherends interface and led to cohesive failure in the joining material. The mechanical strength of Si₃N₄/ Si₃N₄ and Si₃N₄/Invar joined components was measured, with and without laser nanostructuring, before and after thermal cycling from room temperature to 50?K, and it resulted that the exposure to extremely low temperatures did not affect the mechanical integrity of the joints. It was also demonstrated that this laser pre-treatment did not alter the mechanical properties of the ceramic substrate.     

Thermodynamic Properties of Fe3O4-FeV2O4 and Fe3O4-FeCr2O4 Spinel Solid Solutions

Solid solutions of Fe304-FeV204 and Fe304-FeCr204 were prepared and equilibrated with Pt under controlled streams of CO/CO, gas mixtures at 1673 K. The concentration of Fe in Pt was used to determine the activity of Fe304 in the solid solutions. The activity of the second component was calculated by Gibbshhem integration. From these data, the Gibbs energy of mixing was derived for both systems. The experimental results and theoretical values which are determined from calculated cation distribution compare favorably in the case of vanadite solid solutions but not in the case of chromite solid solutions. The difference is attributed to a heat term arising from lattice distortion due to cation size difference. The positive heat of mixing will give rise to a miscibility gap in the system Fe304-FeCr204 at lower temperatures.     

Solid Solubility and Polymorphism in the System Sr2SiO4-Sr2GeO4-Ba2GeO4-Ba2SiO4

The reciprocal salt pair Sr₂SiO₄-Sr₂GeO₄-Ba₂GeO₄-Ba₂SiO₄ was investigated using X-ray powder diffraction and DTA. Unlimited solubility in the low-K₂SO₄ structure type (α') occurs throughout the system above 85°C. The nonlinear changes of some lattice constants of the solid solutions are discussed. A stable monoclinic low-temperature (β) form of Sr₂SiO₄ was found which converts reversibly to the high-temperature α'-modification at 85°C. The enthalpy of the β-α' transition is 51 cal/mol. In the reciprocal salt pair the β-form solid solutions occur in a very narrow region below 85°C.     

The Join Ca2SiO4-CaMgSiO4

New data obtained on the join Ca₂SiO₄-CaMgSiO₄ established a limit of crystalline solubility of Mg in α-Ca₂SiO₄ corresponding to the composition Ca_1.90Mg_0.10SiO₄ at 1575°C. The α-α'Ca₂SiO₄ inversion temperature is lowered from 1447° to 1400°C by Mg substitution in the lattice. α'-Ca₂SiO₄ takes Mg into its lattice up to the composition Ca_1.94Mg_0.06SiO₄ at 1400°C and to Ca_1.96Mg_0.04SiO₄ at 900°C. A new phase (T) reported previously by Gutt, with the approximate composition Ca_1.70Mg_0.30SiO₄, was stable between 979° and 1381°C, and should be stable at liquidus temperatures in multicomponent systems involving CaO–MgO–SiO₂.     

Ionic Conductivity of Li4SiO4, Li4GeO4, and Their Solid Solutions

Conductivity was measured for Li₄SiO₄ and its solid solutions with Li₄GeO₄ over a wide frequency range to separate clearly the effects of electrode polarization, conductance relaxations, etc., and to obtain true "dc" conductivities. The conductivities of all the electrolytes are markedly temperature-dependent, ranging from 10⁻⁸ to 10⁻¹⁰Ω⁻¹ cm⁻¹ at 100°C to 10⁻² to 10¹⁰Ω⁻¹ cm⁻¹ at 700°C. For solid solutions with the Li₄GeO₄ structure, conductivities fit the Arrhenius equation over a wide temperature range, but at higher temperatures a change in activation energy occurs, corresponding to a first-order phase transition. In contrast, solid solutions with the Li₄SiO₄ structure show changes in activation energy which do not correspond to phase transitions, but which appear to indicate changes in the conduction mechanism.     

The System K2SO4-Cs2SO4

The phase diagram for the system K₂SO₄-Cs₂SO₄ was determined by using DTA for melting relations and DTA and high-temperature X-ray diffractometry for subsolidus relations. At the solidus the system shows complete solid solubility, with a minimum at 940°C and 50 mol% Cs₂SO₄. Orthorhombic K₂SO₄ and Cs₂SO₄, the stable low-temperature forms, show mutual solid solubility and form a eutectoid at 50 mol% Cs₂SO₄ and 430°C, the lowest temperature of stability of the high-temperature hexagonal solid-solution phase. Isothermal plots of the a and c dimensions of this hexagonal phase vs composition show large positive deviations from linearity for c. These deviations are interpreted on the basis of the crystal structure of KNaSO₄ with a similar unit cell.