镁条在非酸性电解质水溶液里的反应探讨

室温下,镁条在酸性溶液(如NH4Cl、(NH4)2SO4和NH4NO3等)里有较快的反应速度,而在中性溶液(如NH4Ac、NaCl和Na2SO4等)和碱性溶液(如NH4HCO3、NaHCO3、Na2CO3和NaOH等)里情况如何呢?     

不同电解质溶液对聚吡咯修饰膜性质的影响

以对甲基苯磺酸钠(p-TSNa)为掺杂剂在不锈钢电极表面恒电位合成聚吡咯(PPy)修饰膜, 采用循环伏安法在-1.6 - 0.8 V大范围扫描研究了修饰膜在H2SO4、Na2SO4、NaOH电解质溶液中的氧化还原行为. 结果表明, 在H2SO4溶液中, 以H+的脱出(氧化)/嵌入(还原)为特征, 并发现聚吡咯在酸性溶液中所特有的质子还原峰. 在Na2SO4和NaOH溶液中, 以Na+的脱出(氧化)/嵌入(还原)峰为特征. FT-IR吸收光谱显示, 经NaOH处理后, 聚吡咯膜的长共轭结构被完全破坏, 而经H2SO4和Na2SO4处后, 膜的共轭结构未发生变化.     

卤离子溶液中邻香兰素邻苯二胺对铜的缓蚀作用

应用恒电位稳态极化和交流阻抗技术研究了希夫碱—邻香兰素邻苯二胺 (V_oPh_V)在中性NaCl或NaBr溶液中对金属铜阳极溶解和腐蚀的缓蚀作用 .通过比较铜在空白溶液与含有V_o_Ph_V溶液中的电化学行为解释了V_o_Ph_V的缓蚀机制 .此外还研究了V_o_Ph_V自组装膜在Na Cl溶液中对铜腐蚀的缓蚀效应 .     

无机物离子对CuS微晶形态结构的有效调控

以CuCl2·3H2O,Cu（CH3COO）2·H2O和CuSO4·5H2O作为铜源,并向反应体系中引入少量NaCl或NaNO3,通过乙二醇溶剂中的溶剂热反应,合成了形貌各异的CuS微晶．结合XRD和SEM表征,初步探讨了阴离子Cl-、CH3COO-、SO4^2-和阳离子Na’对CuS微晶生长过程的影响．结果表明,Na＋对CuS微晶的生长过程没有显著影响,而Cl、CH3COO-、SO4^2-由于在{1012}晶面上选择性吸附能力的差异,显著影响CuS微晶的形貌．本研究为进一步有效调控CuS微晶的形貌及性能奠定了基础．     

基于莫高窟成盐元素相关系探究壁画盐害作用机理

壁画盐害与壁画的成盐元素种类、盐分迁徙活动以及环境气象条件等密切相关.莫高窟壁画酥碱病变的可溶盐主要为NaCl和Na2SO4,盐的结晶是破坏力的重要来源.本文运用经典溶液化学的研究方法,界定了三元体系NaCl-Na2SO4-H2O于308K,298K,288K,278K,268K的相关系,以此为基础阐释了壁画盐害的发生和发展规律,计算得到了安全含盐量和环境条件的临界数值.研究表明:NaCl的饱和溶解度对温度敏感度不大,它的结晶析出更多的是伴随着水分的蒸发而发生;Na2SO4的饱和溶解度对温度表现较为敏感,它的结晶析出,除了因溶剂水分的蒸发而发生发展之外,还将因温度的降低而产生,他们各自在壁画盐害的发生发展过程中有一定的行为差异,其主导作用的交替点大致在wNa2SO4 /w NaCl=1:3～6左右,即当该体系中Na2SO4的质量比约达30%～15%时,Na2SO4将成为壁画盐害随洞窟温度变化而发生的主导诱因.三元体系NaCl-Na2SO4-H2O中NaCl和Na2SO4在5～35℃的介稳饱和溶解度的测定,取得了与相图相一致的结果.NaCl结晶物质地坚硬、粒度均匀,在壁画盐害表现形式上应以点状疱疹为主;Na2SO4结晶物主要以十水硫酸钠Na2SO4·10H2O的形式析出,质地疏松,易风化,易返潮,所导致的壁画酥碱病变有一定的反复性.Na2SO4的过饱和溶解度大,易富集,易浓缩,结晶区域较大,相应破坏面也较大,在壁画盐害的表现形式应以粉状酥碱为主,如壁画较大面积的空鼓、地仗层酥松等.     

水热法制备TiO_2纳米线薄膜的光生阴极保护性能

应用水热法在钛箔表面制备TiO2纳米线薄膜,采用场发射扫描电子显微镜、X射线衍射和紫外-可见分光光度法对薄膜进行表征,用电极电位和电化学阻抗谱考察TiO2光生阴极保护性能.结果表明:薄膜由纵横交错的锐钛矿型TiO2纳米线组成,纳米线的直径约10nm.在150℃下反应6h生成的TiO2纳米线薄膜在0.3mol·L-1 Na2SO4溶液和0.3mol·L-1 Na2SO4+0.5mol·L-1 HCOOH混合溶液中对与TiO2薄膜耦连的403不锈钢均有良好的阴极保护效应.TiO2膜所在溶液中含有HCOOH时,可使耦连的403不锈钢在0.5mol·L-1 NaCl溶液中电极电位负移约545mV,界面反应电阻显著变小,表明电解质溶液加入HCOOH可以增强TiO2纳米线薄膜对403不锈钢的光生阴极保护效应.     

Na2B4O7-Na2SO4-NaCl-H2O四元体系288K相平衡研究

采用等温溶解平衡法研究了四元体系Na2B4O7-Na2SO4-NaCl-H2O在288 K的相平衡关系,测定了平衡液相的溶解度及其密度。由研究结果知该四元体系为简单共饱和型,无复盐及固溶体形成。根据实验数据绘制了相应的相图。相图中有一个共饱点,三条单变曲线,三个结晶区平衡固相分别为:Na2B4O7·10H2O,Na2SO4·10H2O和NaCl。实验结果表明NaCl对Na2B4O7和Na2SO4有盐析作用,并简要讨论了实验结果。     

高温高浓度溴化锂溶液对低合金钢的电化学行为作用

通过电化学测式技术和化学浸泡方法 ,在高温 55%LiBr +0 .0 7mol/LLiOH溶液中研究了MoO4 2 - 对低合金钢的电化学行为作用 .结果表明 ,MoO4 2 - 作为阳极型缓蚀剂能促进钝化 ,阻滞了阳极和阴极反应 .Na2 MoO4 浓度达到 2 0 0mg/L时 ,可有效地抑制低合金钢的活性溶解 .低合金钢中添加Cr和Ni元素可改善耐蚀性能 ,而AI元素则使耐蚀性能变劣 .Mo元素参与成膜过程 ,Cr和Mo元素的协调作用 ,使A钢能在较低Na2 MoO4 浓度下进入钝态     

炔醇类缓蚀剂对铁在硫酸溶液中保护作用的光电化学研究

在含不同缓蚀剂的0．5mol/L H2SO4的电解质溶液中,用光电化学方法研究了氧化铁钝化膜的电子传递过程;缓蚀剂的加入在金属表面形成的沉积膜是非光电化学活性的,基本上对光电流的瞬态性质不造成影响;在硫酸溶液中测得两个明显的光电流峰,其禁带宽度值Eg^dir=3.7eV(对应300nm处的弱峰）,Eg^ind=1.95eV(380到500nm范围的强峰）,加入不同缓蚀剂后测得Eg^ind值略有减小;测定电位阶跃下发生的电流瞬态引起电荷量的改变,表明在恒定电位下延长钝化时间会减少膜中羟量和水的含量,而缓蚀剂的加入减少了膜中OH^-和H2O的含量,说明缓蚀剂沉积膜与钝化膜之间存在着化学作用,造成了钝化膜表面附近的化学组成发生变化。     

铜表面二硫代氨基甲酸改性葡萄糖自组装膜的缓蚀作用

合成了一种环境友好型的缓蚀剂--二硫代氨基甲酸改性葡萄糖（DTCG）。 采用该缓蚀剂在铜表面制备了自组装膜,并运用电化学阻抗谱、极化曲线方法研究了该膜在3%NaCl溶液中对铜的缓蚀性能。 研究结果表明,DTCG自组装膜对铜有良好的缓蚀效果,在自组装时间为4 h、自组装浓度为120 mg/L的缓蚀效率接近于97%。 量子化学计算结果也证明了DTCG具有优异的缓蚀性能。     

复方钨酸盐对铜缓蚀协同作用的光电化学和SERS 研究

主要采用光电化学方法和表面增强拉曼光谱技术对具有环境友好性的钨酸盐与BTA复配使用对铜的缓蚀协同效应和作用机理进行了研究。实验表明Na2WO4对铜的缓蚀作用机理与BTA不同,在电位正向扫描过程中,光电流并不发生转型,其大小变化也不大;但在电位负向扫描过程中产生的阴极光电流峰值明显增大,缓蚀剂浓度越大,光电流越大,缓蚀效果越好,而Na2WO4与BTA复配使用时具有较好的协同效应,光电化学和SERS结果都说明其协同机理为两者都能对铜的缓蚀产生作用,前暑能促使电极表面产生的铜的氧化物增多;后者能与铜(Ⅰ)生成聚合物膜。     

STUDY ON THE DESALINATION BEHAVIORS OF PA/PSF THIN FILM COMPOSITE

A polypiperazine amide (PA)/polysulfone (PSF) thin film composite (TFC) was prepared by interfacial polymerization (IP) using a trimesoyl chloride hexane solution as the oil phase and a piperazine aqueous solution as the water phase on a porous polysulfone hollow fiber substrate. Its separating behaviors were investigated systematically to various salts such as NaCl, KCI, Na2SO4,MgCl2, CaCl2 and MgSO4, showing the highest rejection rate to Na2SO4, the second to MgSO4, the third to MgCl2 and CaCl2, and the lowest to KCI, NaCl, being 99%, 98%, 70%, 60%, 15% and 10% respectively. Under an increasing pressure or with time, the rejection rate of the TFC rises to a plateau. To various concentration of the feed, the rejection rate reduced gradually with the higher concentration.     

STUDY ON THE DESALINATION BEHAVIORS OF PA/PSF THIN FILM COMPOSITE

1. INTRODUCTION Nanofiltration (NF) membranes have been known for having properties between those of ultrafiltration (UF) membranes and reverse osmosis (RO) membranes and thus have found applications in many areas especially in rejecting multivalent ions for water softening and charged organic pollutants for wastewater treatment. Because of their advantages, such as low operating pressure, high permeate flux, high retention to multivalent ions and organic molecules with molecular weight …     

Interaction forces in thin liquid films stabilized by hydrophobically modified inulin polymeric surfactant. 3. Influence of electrolyte type on emulsion films

The interaction forces in emulsion films stabilized using hydrophobically modified inulin (INUTEC SP1) were investigated as a function of concentrations of electrolytes of different types (NaCl, Na2SO4, and MgSO4). At a constant disjoining pressure of 36 kPa, a constant temperature of 22 degrees C, and a film radius of 100 microm, the film thickness, hw, decreased with an increase in electrolyte concentration until a critical value, Cel,cr, was reached above which hw remained constant. Cel,cr decreased with an increase in electrolyte valency (Cel,cr = 5 x 10(-2) mol.dm(-3) for NaCl and 1 x 10(-2) mol.dm(-3) for Na2SO4 and MgSO4). The reduction in film thickness below Cel,cr could be accounted for by the compression of the electrical double layer. The Pi-hw isotherms below Cel,cr could be fitted using the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory (constant charge and constant potential cases were considered). At a certain pressure, the film jumped to a Newton black film. The pressure at the jump decreased with an increase in electrolyte valency as a result of the reduction of the electrostatic barrier. At electrolyte (NaCl, Na2SO4, or MgSO4) concentrations higher than Cel,cr, the jump occurred at a low pressure that was independent of the electrolyte type. The thickness of the Newton black film was independent of both the concentration and nature of the electrolytes studied. The results show clearly that the polyfructose loops and tails remain strongly hydrated both in water and in high concentrations of electrolytes of different types, and these results explain the high INUTEC SP1 emulsion stability against coalescence of emulsions prepared under such conditions.     

引发甲基丙烯酸甲酯聚合的聚丙烯酰胺－氯化铜配合物膜催化剂表征

考察甲基丙烯酸甲酯在室温Ｎａ２ＳＯ３水溶液的聚合能力，发现在该溶液添加聚丙烯酰胺（ＰＡＡｍ）－氯化铜（ＣｕＣｌ２）配合物膜以组成ＰＡＡｍ－ＣｕＣｌ２膜／Ｎａ２ＳＯ３催化引发体系是必不可少的．采用ＥＳＲ、ＩＲ、ＸＰＳ和电导率等手段研究该体系催化剂的表面结构．结果表明，膜的单位面积平均含铜量在一定范围内和配位体种类等对催化活性有显著影响，即催化性能与催化剂的表面结构紧密相关．     

Thin wetting films from aqueous electrolyte solutions on SiC/Si wafer

The stability and rupture of thin wetting films from aqueous NaCl or Na2SO4 solutions of different concentrations on silicon carbide were investigated. The flat surface of SiC was obtained by plasma-enhanced chemical vapor deposition (PE-CVD) on top of a silicon wafer. The microinterferometric method was used for measuring the film thickness with time. The light reflectance was calculated as a function of film thickness for the four-layer system: air/aqueous solution/SiC/Si wafer. The microinterferometric experiments showed that films from aqueous NaCl and Na2SO4 solutions with concentrations up to 0.01 M were stable independent of the pre-treatment of the substrate. The pre-treatment of the SiC surface was crucial for the wetting film stability at electrolyte concentrations greater than 0.01 M. The films were unstable and ruptured if SiC was washed with 5% hydrofluoric acid and concentrated sulfuric acid, while they were stable if washing was in sulfuric acid only, without immersing SiC in HF. The average equilibrium film thickness was determined as a function of electrolyte concentration. Measurements of the electrokinetic potential zeta were performed by electrophores of SiC powder in 0.001 M NaCl. It was shown that silicon carbide surface was negatively charged. The theory of heterocoagulation was used for the interpretation of the results. Besides the DLVO forces, the structural disjoining pressure (both positive and negative) has been included in the analysis.     

Effect of background electrolytes and pH on the adsorption of Cu(II)/EDTA onto TiO2

Cu(II)/EDTA adsorption onto TiO2 has been studied with a variation of pH, ionic strength, and type of background electrolytes. Cu(II) adsorption onto TiO2 increased as ionic strength increased when NaClO4 was used as a background electrolyte. This can be explained by the increase of exp(-FPsi/RT) as a part of the electrostatic correction within a surface complexation model. Model predictions described experimental adsorption trends. Types of background anions (ClO4, Cl, NO2, NO3, SO3, and PO4) did not affect adsorption trends and adsorption amounts of Cu(II) onto TiO2. However, different trends were observed with various types of background ions used as ionic strength in EDTA and Cu(II)-EDTA adsorption. EDTA adsorption was decreased by using Na2SO3 and Na3PO4 as background ions, while NaClO4, NaCl, NaNO2, and NaNO3 showed negligible interference on the EDTA adsorption, which matched well with model predictions. The presence Na2SO3 and Na3PO4 also interfered with Cu(II)-EDTA adsorption, to a somewhat greater extent compared to EDTA adsorption, especially at lower pH. This interference was also noted in Cu(II)-EDTA adsorption with a variation of Cu(II)-EDTA concentration at constant ionic strength (3 x 10(-3) M) by using Na2SO3 and Na3PO4, especially at lower ratios of Cu(II)-EDTA to Na2SO3 and Na3PO4. These results suggest that the ratio of Cu(II)-EDTA to Na2SO3 and Na3PO4 is an important factor for the controlling of competition between these background ions and Cu(II)-EDTA onto TiO2. Model prediction generally matched well with experimental adsorption using NaClO4, NaCl, NaNO2, and NaNO3 as backgrounds ions, while a severe deviation was observed in the presence of Na2SO3 and Na3PO4. These results suggest that the mobility of copper ions as Cu(II)-EDTA can be increased from polluted area in the presence of multivalent background ions, especially as the ratio of adsorbates/background ions decreased.     

298.16 K时Na+, Mg2+//Cl-, SO42-, NO3-, H2O体系中NaCl饱和区域相平衡

采用等温溶解平衡法研究了五元体系Na+, Mg2+//Cl-, SO42-, NO3-, H2O在298.16 K下氯化钠饱和平衡体系的溶解度, 获得了相应的投影干盐图、氯图和水图. 研究结果表明, 在298.16 K下氯化钠饱和时, 该五元体系投影干盐图由8个二盐共饱和的双变面、13条三盐共饱的单变线和6个四盐共饱的零变点构成, 存在两种复盐, 8个二盐共饱双变面分别对应于NaCl+NaNO3, NaCl+Na2SO4, NaCl+MgCl2·6H2O, NaCl+MgSO4·Na2SO4·4H2O, NaCl+Mg(NO3)2·6H2O, NaCl+NaNO3·Na2SO4·2H2O, NaCl+MgSO4·7H2O 和NaCl+MgSO4·(1—6)H2O. 讨论了该相图在新疆硝酸盐矿开发利用过程中的应用.     

甲基丙烯酰氧基乙基三甲基氯化铵-丙烯酰胺-丙烯酸三元共聚物水溶液的盐效应研究

用恒定外加盐浓度稀释法,测定了甲基丙烯酰氧基乙三甲基氯化铵 丙烯酰胺 丙烯酸（ＤＭＣ ＡＭ ＡＡ） 三元共聚物（ＡＰＡＭ） 水溶液在分别添加不同种类外加盐时的特性粘数．实验结果表明,当外加盐浓度在一定范围内变化时,所有共聚物在ＮａＣｌ 溶液和ＮａＮＯ３ 溶液中均表现出典型的普通聚电解质粘性行为,而ＤＭＣ 和ＡＡ 近似等摩尔的共聚物在Ｎａ２ＳＯ４ 溶液中则呈现出典型的两性聚电解质粘性行为,各种外加盐对ＡＰＡＭ 溶液特性粘数影响的程度为：Ｎａ２ＳＯ４ ＞ ＣａＣｌ２ ,ＮａＮＯ３ ＞ ＮａＣｌ．     

Preparation of hollow capsule-stabilized gold nanoparticles through the encapsulation of the dendrimer

Nanocrystalline TiO2 powders were rapidly prepared by hydrolysis of Ti(OC4H9)4 under ultrasound irradiation. The influences of acids (HCl, HNO3, and H2SO4) and their corresponding salts (NaCl, KNO3, and Na2SO4) on the crystalline phase and morphology of products were investigated, respectively. Compared with NaCl and KNO3 that show no evident influence on the crystalline phase, HCl and HNO3 have a decisive influence on the crystalline phase of the products. However, both H2SO4 and Na2SO4 are favorable for the formation of anatase. By adjusting the concentration of SO2-(4) in the reaction medium, the contents of anatase and rutile phases in the TiO2 powders can be successfully controlled. The morphology of TiO2 crystallites are shown to be strongly related to the type of acid used in the reaction medium.