Na2SO4掺杂含MgO铝酸钙熟料的结构表征及浸出性能

使用分析纯MgO、CaCO₃、SiO₂、Al₂O₃与Na₂SO₄在1350℃保温1 h合成了掺杂Na₂SO₄的含MgO铝酸钙熟料,在Na₂CO₃溶液体系下研究了其氧化铝浸出性能,通过XRD等分析手段对其晶体结构和自粉化性能进行了研究。结果表明,Na₂SO₄可以显著提升铝酸钙熟料的浸出性能,Na₂SO₄掺杂量由0%提高到4%,熟料的氧化铝浸出率由61.89%提高到92.01%,继续添加Na₂SO₄,浸出性能趋于稳定。由XRD结果可知,Na₂SO₄促使20CaO·13Al₂O₃·3MgO·3SiO₂（Q相）发生分解并使其转变为12CaO·7Al₂O₃（C₁₂A₇）。Na⁺进入C₁₂A₇晶格引起晶格畸变,从而提高C₁₂A₇的氧化铝浸出性能。Na₂SO₄的加入降低了熟料的自粉化性能,Na₂SO₄掺杂量由0%提高到6%,熟料的自粉率由97.46%下降到85.34%,当Na₂SO₄掺杂量达到10%后,熟料自粉率仅为36.3%。     

燃煤锅炉烟气中Na2SO4生成的化学动力学研究

准东煤燃烧过程中Na₂SO₄的形成会造成锅炉受热面沾污、尾部SCR催化剂失活等问题。烟气中Na₂SO₄形成及转化规律的研究对于预测和控制燃煤烟气中Na₂SO₄的形成有重要意义。发展了烟气中Na/Cl/S/O/H化学动力学模型,研究了烟气中Na₂SO₄的生成过程及转化机理,考察了含氧量、温度、SO₂浓度、H₂O浓度等因素对Na₂SO₄生成的影响。动力学计算结果表明,模型预测结果与实验数据吻合较好,验证了模型的准确性。烟气中的高氧气含量有利于Na₂SO₄的生成。高温加快化学反应的同时,抑制了Na₂SO₄的生成。SO₂和H₂O的影响效果受温度影响较大。反应路径分析表明,Na₂SO₄的生成路径有两个：一是依赖于SO₂直接氧化（NaCl→NaSO₃Cl→NaHSO₄→Na₂SO₄）,二是依赖于SO₂间接氧化（NaCl→NaO₂→NaSO₄→NaHSO₄→Na₂SO₄）。敏感性分析结果表明,Na₂SO₄的生成主要对系统中生成或消耗自由基的反应更为敏感。     

Formation of dish-like holes and a channel structure in electrodeposition of copper under hydrogen co-deposition

Copper electrodeposition from acid sulfate solutions at an overpotential of 1000 mV, which is about 250 mV outside the plateau of the limiting diffusion current density, was examined by the determination of the average current efficiency of hydrogen evolution and by the scanning electron microscopic (SEM) analysis of the morphology of the formed copper deposits. Craters or holes formed due to the attachment hydrogen bubbles were the dominant morphological forms of copper deposits obtained at this overpotential. In dependence of the concentration of Cu (II) ions in the plating solution, the two types of holes or craters were formed. One type of holes is obtained by electrodeposition from a solution with a concentration of Cu (II) ions of 0.075 M CuSO₄ in 0.50 M H₂SO₄, and a honeycomb-like structure was formed from these holes. The other types of holes are formed from a solution with a higher concentration of Cu (II) ions (0.60 M CuSO₄ in 0.50 M H₂SO₄) and the formed holes were dish-like. A mixture of both types of holes was obtained by electrodeposition from 0.30 M CuSO₄ in 0.50 M H₂SO₄. The obtained morphologies of copper deposits are discussed in terms of the effect of hydrogen evolution on the hydrodynamic conditions in the plating solution.     

Corrosion inhibition by poly(N-ethylaniline) coatings of mild steel in aqueous acidic solutions

Poly(N-ethylaniline) (PNEA) coatings on mild steel have been electrodeposited from 0.1 to 0.5 M aqueous oxalic acid solutions containing 0.1 M N-ethylaniline (NEA) using potentiodynamic synthesis technique. The effect of oxalic acid concentration on the corrosion behavior of PNEA coated mild steel surfaces were investigated by DC polarization and electrochemical impedance spectroscopy (EIS) techniques in 0.1 M HCl and 0.05 M H₂SO₄ solutions. Corrosion test results showed that corrosion resistance of PNEA coatings decreases with increasing concentrations of oxalic acid in polymerization solution. Decreasing acidity of the polymerization solution causes more effective protection against corrosion in aqueous acidic corrosive medium.     

聚苯胺/钴铁氧体电磁复合材料的制备及其性能

先采用反向共沉淀法制备了钴铁氧体(CoFe₂O₄)磁性纳米颗粒,并以此为核,基于离子液体(IL)环境下,以苯胺为单体,运用原位聚合和化学氧化聚合法制备得到了既具有电性能又具有磁性能的钴铁氧体/酸掺杂聚苯胺--PANI/CoFe₂O₄(IL)复合材料。通过透射电镜(TEM)、X射线衍射分析(XRD)、红外波谱分析(FT-IR)、振动样品磁强计(VSM)和四探针电导率仪等测试手段研究了该复合材料的结构和性质,结果表明:本文实验条件下,制备得到的CoFe₂O₄具有单一的尖晶石型铁氧体结构,且分散性较好,IL存在的反应条件对其晶型没有影响;含相同量钴铁氧体(0.3g CoFe₂O₄)时,在IL和水相中制备的PANI/CoFe₂O₄复合材料的电导率分别为1.0S/cm和0.4S/cm,而饱和磁强度则分别为19.8emu/g和22.9emu/g。此外,IL下得到的复合材料表现出较好的电包磁结构。     

硫酸钠/氧化硅复合定形相变材料的溶胶凝胶法制备和表征简

A sodium sulfate （NaeSO4）/silica （SiO2） composite was prepared as a shape-stabilized solid-liquid phase change material by a sol-gel procedure using Na2SiO3 as the silica source. Na2SO4 in the composite acts as a latent heat storage substance for solid-liquid phase change, while SiO2 acts as a support material to provide structural strength and prevent leakage of melted NazSO4. The microstructure and composition of the prepared composite were characterized by the N2 adsorption, transmission electron microscope （TEM）, scanning electron microscope （SEM）, Fourier transform infrared spectroscopy （FTIR） and X-ray diffraction. The results show that the prepared Na2SOJSiO2 composite is a nanostructured hybrid of NazSO4 and SiO2 without new substances produced during the phase change. The macroscopic shape of the NazSO4/SiO2 composite after the melting and freezing cycles does not change and there is no leakage of Na2SO4. Determined by differential scanning calorimeter （DSC） analysis, the values of phase change latent heat of melting and freezing of the prepared NazSO4/SiO2 （50%, by mass） composite are 82.3 kJ.kg i and 83.7 kJ.kg-1, and temperatures of melting and freezing are 886.0 ℃ and 880.6 ℃, respectively. Furthermore, the Na2SOJSiO2 composite maintains good thermal energy storage and release ability even after 100 cycles of melting and freezing. The satisfactory thermal storage performance renders this composite a versatile tool for high-temperature thermal energy storage.     

Accelerating effect and mechanism of passivation of polyaniline on ferrous metals

To investigate the corrosion protection mechanism of polyaniline (PANI) films on ferrous metals, this work presents preparation method of a separate protonated PANI film electrode and results of its open-circuit potential (OCP) in 0.5 M NaClO₄ and 0.5 M Na₂SO₄ solutions with different pH and the galvanic interaction between the PANI film electrode and ferrous metals. X-ray photoelectron spectroscopy (XPS) shows the lower pH corresponds to higher protonation level of H⁺ in the film, and a more positive OCP of PANI film. The PANI film accelerated the corrosion of 20A carbon steel slightly with a PANI to steel area ratio less than 25:1, while the PANI films maintained passivity for a ratio above to 25:1 for the 20A steel. For the coupling of 2Cr13 stainless steel/PANI, an equal area PANI film could maintain 2Cr13 in a passive state. The results suggest that corrosion protection of 20A carbon steel and 2Cr13 stainless steel by PANI film in the acid solution is due to passivity protection. The excess oxidative charge stored in the PANI and the equilibrium activity of protonated PANI with the acid environment provide a persistent driving force for carbon steel and 2Cr13 stainless steel passivity.     

四元体系Na+,K+//Br-,SO42——H2O373K相平衡

采用等温溶解平衡法研究了四元体系Na⁺,K⁺//Br^-,SO₄^2--H₂O在373 K条件下的相平衡关系,测定了平衡溶液的溶解度和密度,并根据实验数据绘制相应的相图、水图和密度图。研究发现:交互四元体系Na⁺,K⁺//Br^-,SO₄^2--H₂O在373 K温度下,有复盐钾芒硝Na₂SO₄·3K₂SO₄生成,相图由3个共饱和点、7条单变量曲线和5个结晶区组成。其中,5个结晶区分别对应单盐:K₂SO₄,KBr,NaBr,Na₂SO₄和复盐Na₂SO₄·3K₂SO₄(Gla)。     

Chemical activation of blended cements made with lime and natural pozzolans

This paper deals with the chemical activation of lime-pozzolan cement (LPC), which consists of 80% natural pozzolan and 20% hydrated lime (by mass). Results show that the addition of 4% Na₂SO₄ can significantly improve the early strength of this cement. The presence of 4% flake calcium chloride (CaCl₂.2H₂O) is not helpful to early strength, but can increase the later strength substantially. CaSO₄.O.5H₂O and NaCl do not demonstrate an obvious effect on the strength development of the cement. Combination of activators, such as CaCl₂.2H₂O+Na₂SO₄ or Na₂SO₄+NaCl does not improve the activation effect; pastes with 2% Na₂SO₄+2% NaCl show lower strength than the pastes with 2% Na₂SO₄ alone.     

含哌啶阳离子侧长链型一/二价阴离子选择性分离膜的制备

基于超酸催化聚合机理制备了含咔唑片段的聚合物主链结构,并通过调控季铵化反应中N-甲基哌啶单体的用量,得到了不同哌啶离子含量的阴离子选择性分离膜。通过核磁共振氢谱证明了聚合反应和季铵化反应顺利进行。热重和动态机械分析的测试结果表明膜具有优异的热稳定性和力学性能。通过电渗析 （ED） 测试膜的阴离子分离性能,结果显示离子通量和选择性均优于商业膜Neosepta ACS。在NaCl/Na₂SO₄体系中,QPC-Pip-60的Cl^-通量可达3.24 mol·m^-2·h^-1,选择性可达11.6。在NaOH/Na₂WO₄碱回收体系下,良好的微相分离结构使得OH^-通量可达3.59 mol·m^-2·h^-1,选择性最高为70。长时间稳定性测试和碱稳定性测试结果表明所制备的系列膜具有优异的循环稳定性和耐碱性能。     

含哌啶阳离子侧长链型一/二价阴离子选择性分离膜的制备

基于超酸催化聚合机理制备了含咔唑片段的聚合物主链结构,并通过调控季铵化反应中N-甲基哌啶单体的用量,得到了不同哌啶离子含量的阴离子选择性分离膜。通过核磁共振氢谱证明了聚合反应和季铵化反应顺利进行。热重和动态机械分析的测试结果表明膜具有优异的热稳定性和力学性能。通过电渗析 （ED） 测试膜的阴离子分离性能,结果显示离子通量和选择性均优于商业膜Neosepta ACS。在NaCl/Na₂SO₄体系中,QPC-Pip-60的Cl^-通量可达3.24 mol·m^-2·h^-1,选择性可达11.6。在NaOH/Na₂WO₄碱回收体系下,良好的微相分离结构使得OH^-通量可达3.59 mol·m^-2·h^-1,选择性最高为70。长时间稳定性测试和碱稳定性测试结果表明所制备的系列膜具有优异的循环稳定性和耐碱性能。     

N-Zn/TiO2光催化氧化脱硫废液中亚硫酸钠的研究

采用溶胶凝胶法合成了氮、锌共掺杂二氧化钛催化剂（N-Zn/TiO₂）,用于催化氧化双碱法脱硫废液中的亚硫酸钠。通过X射线衍射、红外光谱、X射线光电子能谱和场发射环境扫描电镜对N-Zn/TiO₂催化剂的形貌和结构进行了表征。并考察了催化剂用量、溶液pH、空气流量、亚硫酸钠初始浓度对N-Zn/TiO₂光催化氧化亚硫酸钠的影响。实验结果表明：在不加N-Zn/TiO₂催化剂的情况下,将脱硫废液中的亚硫酸钠完全氧化需要8 h,而N-Zn/TiO₂在紫外光照射下能在1.5 h内将亚硫酸钠催化氧化完全。催化剂的用量对反应速率的影响最大,废液中亚硫酸钠的氧化速率随着催化剂用量的增多呈上升趋势。其次是溶液的pH对亚硫酸钠的氧化有较大影响,随着pH的增大,亚硫酸钠的氧化速率呈先增大后减小的趋势。实验所得到的最优反应条件为：催化剂用量为m（催化剂）/m（亚硫酸钠）=1/100,pH=6.5,空气流量为4 L/min。     

Phase equilibria for salt-induced lysozyme precipitation: Effect of salt concentration and pH

The salt-induced precipitation of lysozyme from aqueous solutions was studied at 25 °C and various pH values by cloud-point investigations, precipitation experiments (analysing the compositions of the coexisting phases) and microscopic investigations of the precipitates. Sodium sulphate as well as ammonium sulphate were used to induce the precipitation. The experimental results are discussed and used to develop a scheme of the phase equilibrium in water-rich aqueous solutions of lysozyme and either Na₂SO₄ or (NH₄)₂SO₄.     

Effect of anions and pH on the ethanol electro-oxidation at a platinum electrode

The electro-oxidation of ethanol and its inhibition by adsorbed chloride ions have been studied by cyclic voltammetry in 0.64 M HNO₃, 0.64 M HClO₄, 0.64 M NaNO₃, 0.64 M NaClO₄, 0.43 M NaNO₃/0.072 M Na₂SO₄ and 0.43 M NaClO₄/0.072 M Na₂SO₄ solutions at 25°C. The results show that these anions and the pH influence the peak current and potential for all three anodic waves. The anion effect is more pronounced in acidic solutions than in neutral solutions. The magnitude of the effect in the absence of chloride indicates that the surface coverage of these anions increases in the order perchlorate, sulfate, nitrate. The chloride inhibition is dependent on the anions and is smallest in sulfate solutions. Mechanisms proposed in an earlier study are found to be consistent with these results. It is also suggested that the ethanol system may be useful as a probe in studies of anion adsorption properties and platinum surface states.     

纳米SiO2-CSA-OPC复合修补砂浆的抗盐渍土侵蚀性能研究

为了研究纳米SiO2-硫铝酸盐水泥-普通硅酸盐水泥(NS-CSA-OPC)复合修补砂浆的抗盐渍土侵蚀性能,采用在NaCl溶液、Na2 SO4溶液及NaCl-Na2 SO4复合溶液下的长期半浸泡试验模拟盐渍土侵蚀环境,以加速侵蚀NS-CSA-OPC砂浆试件.试验测试了3种侵蚀环境下,NS-CSA-OPC修补砂浆质量、相对...     

Fabrication of anti-fouling polyamide nanofiltration membrane by incorporating streptomycin as a novel co-monomer

Polyamide (PA) thin-film composite (TFC) nanofiltration (NF) membrane has extremely broad application prospects in separation of monovalent/divalent inorganic salts mixed solution. However, membrane fouling is the main obstacle to the application of PA, TFC and NF membrane. Streptomycin (SM) is a hydrophilic antibiotic containing a large number of hydroxyl and amino groups. In this work, the NF membrane was prepared via interfacial polymerization (IP) between trimesoyl chloride (TMC) in the organicphaseand SM/piperazine (PIP) mixture in theaqueousphase. The NF membrane structure and performance were characterized in detail. The results showed that SM successfully participated in the IP. The negative charge and hydrophilicity of membrane surface were improved. The prepared membrane exhibited good anti-adhesion and anti-bacterial performance. Additionally, when the SM concentration was 2%, the prepared membrane exhibited the optimal permselectivity. The water permeance was 89.4 L·m^-2·h^-1·MPa^-1. The rejection of NaCl and Na₂SO₄ were 17.17% and 97.84%, respectively. The NaCl/Na₂SO₄ separation factor of the SM2-PIP/TMC membrane in 1000 mg·L^-1 NaCl and 1000 mg·L^-1 Na₂SO₄ mixed solution was 40, which was 3.3 times that of PIP/TMC membrane. It indicated that SM2-PIP/TMC demonstrated excellent monovalent/divalent salts separation performance. This work provided an easy and effective approach to preparing anti-fouling NF membrane while possessing superior monovalent/divalent salts separation performance.     

New degradation mechanism of Ti/IrO2 + MnO2 anode for oxygen evolution in 0.5 M H2SO4 solution

Degradation mechanism of Ti/IrO₂(0.7) + MnO₂(0.3) anode for oxygen evolution was studied in 0.5 M H₂SO₄ solution by field emission scanning electron microscopes (FESEM), Tafel slope, X-ray diffraction (XRD) and electrochemical impedance spectroscopic (EIS). The whole surface of the non-electrolyzed Ti/IrO₂(0.7) + MnO₂(0.3) anode consisted of nano-IrO₂ poles array. The anode surface had hardly discovered cracks and had compact morphology that can prevent the electrolyte from entering the Ti/oxide interface and an insulating TiO₂ film from growing on the Ti-based surface. An insulating TiO₂ phase had not been generated on the Ti/oxide interface during the process of O₂ evolution and the inactive anode surface still remained mass of the IrO₂ and MnO₂ oxides. The chemical dissolution of Ti/IrO₂(0.7) + MnO₂(0.3) anode coating was not the main reason for electrode degradation in 0.5 M H₂SO₄ solution. The degradation mechanism of Ti/IrO₂(0.7) + MnO₂(0.3) anode differed from other conventional oxide electrodes for O₂ evolution in acid medium. The platforms of Tafel slope and anode potential (900–1050 h) indicated that the change of the oxygen evolution reaction (OER) mechanism was the main reason for degradation of Ti/IrO₂(0.7) + MnO₂(0.3) anode due to the change of adsorption intermediate.     

Hot corrosion and protection of Ti2AlC against Na2SO4 salt in air

The hot corrosion behavior of Na₂SO₄-coated Ti₂AlC was investigated by means of thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy/energy dispersive spectroscopy. This carbide displays good hot corrosion resistance below the melting point of Na₂SO₄ while the corrosion attacks become virulent when the salt is molten. A protectively continuous Al₂O₃ layer forms and imparts good corrosion resistance, and consequently, the corrosion kinetics is generally parabolic at 850 °C. However, porous oxide scales fail to protect the Ti₂AlC substrate at 900 and 1000 °C. The segregation of sulfur at the corrosion scale/substrate interface accelerates the corrosion of Ti₂AlC. Furthermore, a convenient and efficient pre-oxidation method is proposed to improve the high-temperature hot corrosion resistance of Ti₂AlC. An Al₂O₃ scale formed during pre-oxidation treatment can remarkably restrain the infiltration of the molten salt into the substrate and prevent the substrate from severe corrosion attacks.     

模拟城市垃圾焚烧中硫化合物对重金属Cd迁移分布的影响

The effect of sulfur compounds （including sulfur, sulfide, sulfite and sulfate）, initial concentration of heavy metal and operating conditions on Cd emission in municipal solid waste （MSW） incineration were investi-gated using a simulated tubular furnace and simulated MSW spiked with Cd. The concentration of Cd was meas-ured by inductively coupled plasma-atomic emission spectrometry （ICP-AES） after digesting the samples including bottom ash, fly ash and flue gas according to related USEPA methods. The results show that S and Na2S tend to in- crease Cd partitioning in bottom ash, whereas Na2SO3 and Na2SO4 tend to reduce Cd partitioning in bottom ash. The effect of sulfur compounds on Cd partitioning in bottom ash was in the sequence of Na2S〉S〉Na2SO3〉 Na2SO4. chemical equilibrium analysis is also performed to determine the effect of sorbents on Cd adsorption. The calculations show that S presents strong affinity for Cd and restrains Cd adsorption by SiO2, whereas when temperature rises to between 830℃ and 1030℃, Cd adsorption efficiency of SiO2 is over 80% and the efficiency of Al2O3 is up to 85%.     

Hot-corrosion of silicon carbide in combustion gases at temperatures above the dew point of salts

To evaluate the performance of SiC to operating environments expected in future ceramic gas turbines, SiC samples were exposed in a low velocity burner rig at temperatures above the dew point of sodium sulphate (Na₂SO₄). Under these conditions, the corrosion behaviour should be independent of the sulphur content of the fuel, if Na₂SO_4(g) is not involved in the corrosion process. At 1000°C, SiC degradation was dependent on the sulphur levels in the fuel and the rates were controlled by the properties of the glassy corrosion products. Although there was an effect of P_SO3 on a_Na2O at 1300°C, the formation of an inner crystalline silica layer protected the material in both combustion gases so that the effect of p_SO3 on corrosion was concealed. These results indicate that Na₂SO_4(g) is involved in the corrosion process at temperatures above the dew point, contrary to what might be predicted from thermodynamic considerations. The role of sodium on enhancing the rate of corrosion is discussed.