Immobilization of new Mn(salen) complex over MCM-41 and its activity in asymmetric epoxidation of styrene

New tetradentate chelates of bis-Schiff bases were synthesized and then these chiral salen ligands were immobilized over mesoporous MCM-41 by using the ion-exchange method. The efficiency of the chiral catalyst was examined in the asymmetric epoxidation of styrene. Chiral Mn(salen) complexes immobilized onto mesoporous MCM-41 were stable during the reaction without any leaching and exhibited relatively high enantioselectivity for epoxidation as compared with homogeneous complexes. This revised version was published online in August 2006 with corrections to the Cover Date.     

Electrodeposition of silver from nitrate solution: Part II. Mechanism of the effect of phosphate ions

The mechanism of compact Ag-film formation by electrolysis from nitrate solution with addition of small amounts of phosphate ions is elucidated. It is shown that the phosphate ions exert their effect by lowering the exchange current density. Consequently, the radii of nucleation exclusion zones also diminishes, thus producing conditions stimulating electrodeposition of continuous thin Ag-film.     

由双酚A结晶母液的裂解产物合成双酚A反应过程研究

对反应过程所需催化剂种类及其各影响因素进行了考察。研究表明，大孔强酸性离子交换树脂可替代无机酸作为催化剂用于该反应，其中以未经硫基化处理者为佳；原料中水分的存在不利于产物收率和质量，应控制水的质量分数在1％以下。本研究确定的较佳工艺条件为反应温度65℃，停留时间15min、苯酚／对－异丙烯基苯酚摩尔比20，对应的反应收率为98．5％。对双酚A副产物的处理提供了有效方法。     

新型菌丝体包覆吸附剂的制备及对Ni2+离子吸附性能的研究

以菌丝体为核心材料 ,在其表面包覆壳聚糖膜作为吸附介质 ,制备成新型菌丝体包覆吸附剂。系统研究了菌丝体包覆吸附剂的制备工艺及吸附剂对Ni2 + 的吸附特性 ,结果表明 ,菌丝体作核心材料优于花生壳 ,菌丝体包覆吸附剂对Ni2 + 的吸附容量比普通菌丝体水处理剂提高了 50 % ,并可以重复使用 1 0次 ,吸附容量没有明显降低 ;同时菌丝体包覆吸附剂对Ni2 + 的吸附特性较好地符合Langmuir等温方程和Freundlich等温方程     

壳聚糖固定化脲酶生物传感器选择性测定铜离子

基于重金属对脲酶的抑制作用,研制了用于测定铜离子的生物传感器。该生物传感器的制备以壳聚糖为载体,将脲酶固定于pH电极表面。由于壳聚糖对Cu2+的富集,该生物传感器展现出高灵敏度。在样品溶液中加入5 mmol/L NaI,可以消除Hg2+和Ag+的干扰,从而实现Cu2+的选择性检测。在0.005～0.5μg/mL的浓度范围内,脲酶活性的抑制率与Cu2+浓度的对数呈良好的线性响应关系,其检出限为0.002μg/mL。将使用后的生物传感器浸泡于0.5 mmol/L的EDTA溶液再生5 min,被Cu2+抑制的脲酶的活性可以得到恢复。     

Rinsing effect of alkaline electrolyzed water on nickel surfaces

The improvement in the surface cleanliness of electroplated nickel by rinsing in alkaline electrolyzed water (AEW) was determined. When the nickel plated sample was rinsed with the AEW, it was found that the amount of residual sulfate ion on the surface of a sample decreased approximately by half compared to one rinsed only with de-ionized pure water. Because nanosize hydrogen bubbles are present in the AEW, and the zeta-potential has a negative value, we then surmised that the mechanism of rinsing was as follows: The sulfate ions are selectively absorbed on the nanosize colloidal hydrogen bubbles, or substituted for anions absorbed on the hydrogen bubbles. The sulfate ions absorbed on the nickel surface then become detached. The detached sulfate ions are absorbed on the surface of the hydrogen bubbles, and negatively charge the hydrogen bubbles. It can be considered that any detached sulfate ions do not re-adhere due to the electrical repulsion force of the negatively charged nickel surface. Thus the sample is efficiently rinsed.     

掺铜TiO^2光催化剂光催化氧化还原性能的研究

利用浸渍法制备了掺铜二氧化钛光催化剂，分别以乙酸降解和二氧化碳还原反应为探针，研究了催化剂的光催化氧化光催化还原性能．结果表明，铜掺杂能显著提高催化剂的光催化性能；结合光电子能谱、X光衍射分析等物理表征结果，对铜掺杂改性机制进行了讨论．     

Sorption of Cr(III)‐containing cations on strongly basic anion exchangers

It is shown that strongly basic anion exchangers AV‐17 and Varion‐AD in definite conditions are able to retain Cr(III)‐containing ions from Cr(III) sulfate solution. It is found that the sorption of Cr(III)‐containing ions on the polymers is essentially dependent on the pH, temperature, and Cr(III) sulfate concentration. The maximum temperature dependence of sorption was found to be about 60°C. The sorption isotherms are well described by Langmuir's equations. The sorption kinetics is determined by the diffusion of Cr(III)‐containing ions into polymer's phase. It is assumed that the Cr(III)‐containing ions are retained through formation, in polymer's phase, of the jarosite‐type mineral compounds: R₄N[Cr₃(OH)₆(SO₄)₂], H₃O[Cr₃(OH)₆(SO₄)₂], and K[Cr₃(OH)₆(SO₄)₂]. For comparison of sorptional capacities, the sorption of Cr(III)‐containing ions was determined on different cation and anion exchangers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3978–3985, 2006     

邻菲啰啉分光光度法测定离子膜碱中的三氧化二铁

介绍采用邻菲啰啉分光光度法对离子膜碱中三氧化二铁进行的测定,并就吸收曲线、邻菲啰啉铁络合物的稳定性、显色剂浓度对照试验、邻菲啰啉与铁的摩尔比、溶液酸度对络合物的影响以及共存离子消除等条件进行了探讨,以能更好地满足实际检测工作的需要.     

The synthesis and characterization of the molecular sieve SAPO-16 as well as other SAPO and CoAPO phases using bis(cyclopentadienyl) cobalt(III) hydroxide as a structure directing agent

The clathrate type molecular sieve SAPO-16 was prepared via a hydrothermal synthesis using bis(cyclopentadienyl)cobalt(III) hydroxide, Cp₂CoOH, as a template and characterized by XRD, FT-IR, UV-Vis and SEM. Additionally, the preparation and characterization of possibly new isostructural SAPO-UTD-3 and CoAPO-UTD-3 materials is reported.NSF Presidential Young Investigator 1991–1996.