负载型K2CO3/Al2O3二氧化碳吸收剂的碳酸化反应特性

The carbonation characteristics of K₂CO₃/Al₂O₃ supported sorbent for CO₂ capture was investigated with thermogravimetric apparatus（TGA）,X-ray diffraction（XRD）,scanning electron microscopy analysis（SEM）and N₂ adsorption.The results showed that the carbonation rate of K₂CO₃ before being loaded on Al₂O₃ was slow.However,the K₂CO₃/Al₂O₃ upported sorbent showed excellent carbonation performance.The difference in carbonation behavior between K₂CO₃ nd K₂CO₃/Al₂O₃ supported sorbent was analyzed from the microscopic view.The analytical reagent K₂CO₃ sample was of monoclinic crystal structure and could react quickly with H₂O in the experimental carbonation environment to produce K₂CO₃•1.5H₂O,which was unfavorable to carbonation reaction.When K₂CO₃was loaded on Al₂O₃,the surface area and porosity of the sorbent was improved greatly.So the carbonation properties of the K₂CO₃/Al₂O₃ supported sorbent was also improved.     

碱性溶液中硼氢化钠在铜阳极上的氧化行为

Polarization data of BH^-₄ oxidation on Cu anode in alkaline solution were measured at steady state by a self-made experimental cell. The experimental polarization curve showed three regions：the region at lower over-potential η（below 0.4 V approximately）,the region at higher η（above 0.6 V approximately）and the transitional region at medium η. It was found that the limiting current density is caused by the limiting elemental step rather than the external mass transport. The apparent reaction order with respect to BH^-₄ changes from 0 to 1. The active energy is about 40 kJ·mol^-1 in both regions with lower and higher η,and is higher than 40 kJ·mol^-1 in the transitional region. With the experimental temperatures and NaOH concentration,the hydrogen production rates released by the electrode reaction were measured at ［BH^-₄］/［OH^-］ratios of 1∶40,1∶20,1∶6. 7 and 1∶4,which is strongly dependent on the over-potential. The apparent number of released electron n by the reaction was calculated by using the measured amounts of hydrogen and coulomb. Higher value of n was obtained at lower ［BH^-₄］/［OH^-］ratio,higher temperature as well as higher over-potential. Under the experimental conditions,the value of n varies from 0 to 7,while in the transitional region it is just in the range of 3 to 5. The experimental results indicate that the limiting current density or n value will increase by virtue of proper experimental conditions. However,to considerably increase the current density at lower over-potential requires a modified anode with higher activity.     

新型聚两性电解质污水处理剂的制备

Mg₃Al layered double hydroxides (Mg₃Al-LDH_EPCL) was grafted through free radical polymerization using S₂O^2-₈/S₂O^2-₅ redox initiator.Monomers used for the graft copolymerization were composed of anionic monomers acrylic acid (AA) and sodium acrylate (SA) as well as cationic monomers trimethylallyl ammonium chloride (TMAAC) and dimethyldiallyl ammonium chloride (DMDAAC).The produced hybrid graft copolymer, Mg₃Al-LDH_EPCL-g-PAA-PSA-co-PTMAAC-co-PDMDAAC, can be used as polyampholyte sewage treatment agent.The graft copolymerization process was monitored by differential scanning calorimetry (DSC) to obtain the kinetic characteristics in the foamed dispersion polymerization system.The graft copolymerization composition was optimized aiming to achieve lower water content in the sludge and lower COD value in the filtrate.The optimized composition was found to be m(Mg₃Al-LDH_EPCL )∶m(AA+SA+TMAAC+DMDAAC)=0.12∶1;m(TMAAC+DMDAAC)∶m(AA+SA+TMAAC+DMDAAC)=0.288∶0.712, and the neutralization ratio of AA was 18%—24%.Hydrolysis analog studies in 1.0 mol•L^-1 NaOH solution revealed that the layered cluster of Mg₃Al-LDH_EPCL hydrolyzed into multiple lamellar segments forming a secondary quaternary ammonium polyampholyte that functioned as coagulation agent.These inherent structural characteristics are important factors for improving the dehydration effect significantly.The crystal structures were characterized by XRD and IR.     

利用翅片管束外表面降膜反应脱除烟气中SO2的实验研究

A new wet flue gas desulfurization method by reaction across the falling liquid film on the outside surface of axial finned-tube bundle and its principles of removal of SO₂ are presented in this paper.The effects of different styles of tube bundle,and the pitch of tubes,flue gas velocity,gas-liquid ratio and flue gas temperature on desulphurization efficiency and the moisture content of flue gas are studied.The experiment results show that desulphurization effect is better for flue gas at 65℃,4.0m·s^-1 against the tube bundle of 10 rows with relative pitch of staggered rows S₁/d=2.1,S₂/d=1.8.     

纳米CeO2搀杂对Ni-P化学镀层微观结构与耐蚀性能的影响

Ni-P and its nano-CeO₂ doped coating were electrolessly prepared in acidic condition,and their microstructure and anti-corrosion property were studied and compared.Scanning electronic microscopy（SEM）,transmission electronic microscopy（TEM）,X-ray diffraction spectrometer（XRD）and differential scanning calorimeter（DSC）were used to examine surface morphology and microstructure of coatings.The results showed that Ni-P coating had partial amorphous structure mixed with nano-crystals,while the Ni-P/CeO₂ coating had perfect amorphous structure.Upon heating,Ni₃P precipitation and Ni crystallization took place in both coatings but at different temperatures of phase change.In addition,the Ni-P/CeO₂ coating had sintered phase of NiCe₂O₄ spinels.The anti-corrosion property and passivity were improved in the CeO₂-doped coating because it was less liable to undergo localized corrosion and had a slower corroding rate than its CeO₂-free counterpart.During the co-deposition process,some Ceⁿ⁺（n=3,4）ions might be adsorbed to the metal/solution electrical double layer and hinder nickel deposition.Ni-P/CeO₂ coating’s perfect amorphous structure was probably due to the hindered crystal-typed deposition of nickel and the promoted deposition of phosphorous.     

负载型钾基CO2吸收剂的结构表征和碳酸化反应特性

The structure identification and carbonation characteristics of several potassium-based supported sorbents for CO₂ capture were investigated with TGA,XRD,XRF,SEM and N₂ adsorption method.Potassium-based sorbents were prepared by impregnation with potassium carbonate on supports,such as cocoanut activated charcoal（AC1）,coal active carbon（AC2）,silica gel（SG）and diatomite（DT）using the iso-volume impregnation method.The results showed that the K₂CO₃ loading amounts of AC1,AC2,SG and DT were 24.1%,22.5%,21.7% and 19.1% respectively.The surface area and pore volume of K₂CO₃/AC1 and K₂CO₃/AC2 were larger than others.In contrast,those of K₂CO₃/DT were small.For K₂CO₃/SG,pore volume was large but surface area was small.K₂CO₃/AC1 and K₂CO₃/AC2 showed excellent carbonation capacity.However,the carbonation capacities of K₂CO₃/SG and K₂CO₃/DT were low.The difference in carbonation capacity of those sorbents were attributed to the difference in pore structure,leading to different supported sorbents.     

可变的分子连接性指数在有机化合物反磁磁化率拓扑研究中的应用

For predicting the molar diamagnetic susceptibilities of organic compounds, a variable molecular connectivity index ^mχ^′ and its converse index ^mχ^″ based on adjacency matrix of molecular graphs and the variable atomic valence connectivity index δ^′I were proposed.The optimal values of parameters a, b, and y included in definition of δ′_i,^mχ^′and ^mχ^″can be found by optimization method.When a=1.10, b=2.8, and y=0.36, a good five-parameter model can be constructed from ^mχ^′and ^mχ^″by using the best subsets regression analysis method for the molar diamagnetic susceptibilities of organic compounds.The results showed that the current method is more effective than literature methods for estimating the molar diamagnetic susceptibility of an organic compound.     

催化剂的制备及其 用于菜籽油制备生物柴油的研究

采用等体积浸渍法制备了纳米K₂CO₃/γ-Al₂O₃催化剂,并研究了该催化剂的制备条件对酯交换反应的影响。用TEM表征催化剂颗粒的大小,用TG-DSC表征催化剂的热性能。结果显示:催化剂粒径分布在30-50nm之间;催化剂的最佳制备条件是K₂CO₃负载率(K₂CO₃占γ-Al₂O₃质量分数)50%,焙烧温度600℃,焙烧时间4h。利用此催化剂,当醇油物质的量之比为12:1、催化剂用量为油质量的3%、反应时间3h 、反应温度70℃时,生物柴油的得率达到97.90%。生物柴油质量指标符合国家标准。     

PVAm/PAN复合膜的制备及其对CO2/CH4的分离性能

New polymeric membrane materials——polyvinyl amine (PVAm) with different primary amine contents were synthesized.By covering polyacrylonitrile(PAN) ultrafiltration membranes with PVAm, the PVAm/PAN composite membranes for CO₂/CH₄ separation were prepared. The composite membranes containing more primary amino groups have higher selectivity for CO₂/CH₄.The cross-linking of acid or glutaradehyde could improve the gas permselectivity of the composite membranes. With decreasing CO₂ content in the feed gas, the CO₂/CH₄ separation factor increased.When the feed gas was 25%(vol) CO₂ and 75%(vol) CH₄, the CO₂ permeation rate was 4.1×10^-9cm³(STP) •cm^-2•Pa^-1•s^-1, and the CO₂/CH₄ separation factor was 180.     

气固流化床混沌动力结构突变分析

A new method called structural catastrophe analysis was applied to the analysis of pressure fluctuation time series with chaotic and fractal characteristics in gas-solids fluidized bed.In every type of fixed bed,bubbling bed,turbulent bed,fast fluidized bed and pneumatic conveying stage,pressure fluctuation signals were sampled and dynamic exponents were solved.The changes of T_mean and T_max in different types of fluidized bed were analyzed and summarized.It was concluded that T_mean and T_max can indicate different types of fluidized,and T_max can also be recognized as a new characteristic parameter in addition to correlation parameters,LE exponent and K entropy.     

碳钢在Na2CO3-NaHCO3溶液中的阳极极化行为

使用动电位极化技术研究了碳钢在Na₂CO₃-NaHCO₃溶液中的阳极极化行为，测试结果表明，阳极极化曲线上存在着两个电流峰和两个钝化区.与在NaHCO3溶液中相比，碳钢在Na₂CO₃-NaHCO₃溶液中的极化曲线上的第一个钝化区变得更宽.当增加NaHCO₃浓度后，两个峰值电位均往正方向移动，表明碳钢的钝化能力降低.研究发现，第二个电流峰对应的电位与NaHCO₃浓度的对数呈良好的线性关系.根据铁在Na₂CO₃-NaHCO₃溶液中的腐蚀热力学，推测该峰处发生的反应可能是：3FeCO₃+4H₂O---Fe₃O₄+3HCO^-₃+5H⁺+2e.XPS分析表明铁电极表面主要由二价铁和三价铁的氧化物组成，进一步支持了以上反应.     

用尿素作沉淀剂制备不同CeO2前驱体

引言 稀土元素由于其本身特有的f电子构型而具有独特的光、电、磁等性质.二氧化铈是一种重要的稀土材料,在玻璃、陶瓷、磨料、催化剂等方面都有着广泛的应用,因此,其合成及应用具有巨大的开发前景.     

Cu2+催化过硫酸钾氧化吸收气态汞

引言 Lipfert等[1]认为1000 MW电站锅炉排放的汞可使附近居民食用鱼中甲基汞水平增加一倍.由于甲基汞在环境中的挥发性、持久性和生物累积性以及对神经的影响,因此,在1990年的美国空气清洁法案(CAAA)中,汞受到了极大的关注.     

Fenton处理对氯酚过程中间产物对Fe3+的还原作用

为探明Fenton处理对氯酚（4-CP）过程中Fe²⁺再生的途径,考察了反应过程Fe²⁺的浓度变化,同时对4-CP降解中间产物和Fe³⁺之间的氧化还原反应进行了研究.Fenton氧化对氯酚过程中Fe²⁺的浓度基本不变;而在•OH捕获剂丙醇的存在下,反应开始后1 min Fe²⁺的浓度急剧下降到10％.研究结果表明：H₂O₂、•OH、HO₂•与O^-₂•等自由基对Fe²⁺的再生净贡献较小,4-CP降解的中间产物对Fe³⁺的还原是Fe²⁺再生的主要途径.Fenton处理4-CP产生的中间产物有对苯二酚和对苯醌.对苯二酚能够快速还原Fe³⁺,使Fe²⁺得到再生;而对苯醌还原Fe³⁺的作用很微弱.这一研究有助于更好地了解Fenton氧化过程中Fe²⁺的再生.     

纳米MnO2离子筛的锂吸附性能

通过控制水热合成反应条件制备了不同晶相的一维纳米MnO₂，进一步用浸渍法制备了Li-Mn-O三元氧化物前驱体，并经酸处理后得到对锂离子具有特殊选择性的离子筛。用XRD、TEM、吸附等温线及反应动力学等手段对产物的晶相结构和锂吸附性能进行了研究。实验结果表明，反应物浓度对MnO₂不同晶面的生长速率有不同的影响；从TEM图像中可以清楚地看到，水热合成法制备出了尺寸为φ5nm×400nm的一维MnO₂纳米线；在pH＝9.19时每克离子筛的单分子层锂离子饱和吸附量Q_m为2.43mmol·g^-1；吸附速率常数为2.17×10^-6 s^-1；吸附量随溶液pH值的增加而增加，当pH=12.5时，相应的吸附量为3.47mmol·g^-1。     

钾基CO2吸收剂的碳酸化反应特性

对钾基CO₂吸收剂的碳酸化反应机理进行研究。利用热重分析、XRD、扫描电镜和氮吸附仪进行试验。结果表明：分析纯碳酸钾的组分为K₂CO₃·1.5H₂O,碳酸化反应速率缓慢;先将分析纯碳酸钾样品脱除结晶水后再进行碳酸化反应时,K₂CO₃与气氛中的水蒸气迅速生成K₂CO₃·1.5H₂O,不利于碳酸化反应的进行;由KHCO₃分解产生的K₂CO₃却表现出优越的碳酸化反应性能,20 min内转化率高达85%以上,经过多次循环试验后吸收剂仍保持很高的活性。从微观角度分析了两种改性钾基CO₂吸收剂碳酸化反应机理差异的原因,通过拟合计算得到了这3种钾基吸收剂的碳酸化反应速率常数,为干法K₂CO₃/KHCO₃循环脱除CO₂的研究提供了一定的基础数据。     

Studies in Lithium Oxide Systems: I, Li2O B2O3–B2O3

Phase relationships in the system Li₂O, B₂O₃-B₂O₃ were studied by the quenching method using twenty compositions. The crystalline phases encountered were (a) Li₂O, B₂O₃, which melts congruently at 849°± 2°C., (b) Li₂O.-2B₂O₃, which melts congruently at 917°± 2°C., (c) a new compound, 2Li₂O-5B₂O₃, which melts incongruently at 856°± 2°C. and dissociates below 696°± 4°C., (d) Li₂O.3B₂O₃, which melts incongruently at 834°± 4°C. and dissociates below 595°± 20°C., and (e) probably Li₂O.4B₂O₃, which melts incongruently at 635°± 10°C. Reactions were sluggish at temperatures near 600°C., resulting in metastable relations. Hence phase equilibrium data relating to the lower stability limit of Li₂O.3B₂O₃ and to the upper stability limit of Li₂O.4B₂O₃ are considered to be tentative. Properties of the glasses and crystalline phases were studied. The refractive index of the glasses increased with the addition of Li₂O up to 22%, but further additions up to 40% had no substantial effect. Glasses containing less than 30% Li₂O were water soluble. Limited data on the density and thermal expansion of the glasses are presented. Li₂OB₂O₃ was euhedral, lath-shaped, length-fast, biaxial negative (2V = 27°), with n_α= 1.540, n_β= 1.612, n_γ= 1.616. Li₂O.2B₂O₃ was uniaxial negative, with n_e= 1.560, n_w= 1.605. Li₂O.3B₂O₃ was biaxial negative (2V = 75° to 80°), with n_α= 1.576, n_β= 1.602, n_γ= 1.605. X-ray powder diffraction data for the five crystalline compounds are presented. Thermal expansion data for Li₂O-B₂O₃ and Li₂O.2B₂O₃ and limited data on the fluorescent properties of the compounds are given. X-ray diffraction data are also presented for Li₂O.B₂O₃.4H₂O and Li₂O.-5B₂O₃. 10H₂O. Li₂O B₂O₃ was obtained by heating the first hydrate at 450° to 680° C. X-ray diffraction showed Li₂O.4B₂O₃ and Li₂O-3B₂O₃ to be the crystalline products obtained during heating the decahydrate at 500°C. and 600°C., respectively.     

动态UV-vis/H2O2/草酸铁络合物法光解苯胺

UV -vis/H₂ O₂ /草酸铁络合物法是一种高级氧化工艺 ,这个工艺产生的羟自由基·OH是一种很强的氧化剂 ,能很快和水中有机物发生反应 .以苯胺为处理对象对该法的氧化能力和效果进行了研究 ,并确定了降解苯胺的最佳工艺条件 :pH =3 .5 ,Fe^{2 +} ∶H₂ O₂ ∶C₂ O^{2 -}₄ ≈ 1∶4∶6 (mole) .UV -vis/H₂ O₂ /草酸铁络合物法处理高浓度苯胺水样非常有效 ,12min内苯胺去除率均在 99%以上 .流动法处理苯胺模拟废水的效果明显好于静态法     

Gd3+掺杂TiO2纳米粉体的晶粒尺寸、表面特性和光催化活性

利用酸催化的溶胶-凝胶法制备了纯的和不同Gd³⁺掺杂量的TiO₂纳米粉体，并用XRD、BET、XPS、SPS等技术对样品进行了表征.研究了Gd³⁺掺杂量和焙烧温度对样品光催化降解亚甲基蓝的活性、相结构、晶粒尺寸和表面织构特性的影响，并结合表面光电特性和表面组成等探讨了Gd³⁺掺杂对纳米TiO₂的光催化活性的影响机制.结果表明：与纯TiO₂相比，适量掺杂Gd³⁺可以显著提高其光催化活性.当Gd³⁺掺杂量为0.5%（质量），焙烧温度为500 ℃时，TiO₂复合纳米粉体的光催化活性最佳，其锐钛矿含量为100%，平均晶粒粒径为15.55 nm，比表面积为12.81 m²·g^-1.Gd³⁺掺杂强烈地抑制TiO₂由锐钛矿相向金红石相的转变，减小晶粒尺寸，提高光响应阈值，这三方面均有利于提高光催化活性.XPS分析表明，Gd³⁺掺杂导致TiO₂纳米粉体的表面羟基含量降低.