镁铝类水滑石对阳离子染料中性红的吸附及机理研究

研究了镁铝类水滑石对中性红的吸附及其作用机理,考察了时间、pH、温度、电解质浓度等因素对吸附作用的影响。结果表明,镁铝类水滑石对中性红的吸附动力学符合准二级动力学方程,热力学符合Langmuir吸附等温式。在实验范围内,吸附量随溶液pH的增大而增加,随温度的升高而降低,随电解质浓度的增加先增加后降低。吸附过程是放热、熵减小的自发过程。镁铝类水滑石对中性红的吸附缘于为类水滑石与中性红分子中π电子的较强静电吸引作用。     

Recent advances in polymer network liquid crystal spatial light modulators

Polymer network liquid crystal (PNLC) spatial light modulators are attractive for display and photonic applications because they can achieve submillisecond response time while keeping a large phase change. However, their on-state scattering caused by the grain boundary of LC multidomains hinders their applications. In this article, we review recent progress on the development of scattering-free PNLCs extending from short-wavelength infrared to visible region by reducing the domain sizes to ∼200 nm through low temperature curing process. To reduce operation voltage, both transmissive and reflective modes, LC material properties (birefringence and dielectric anisotropy), polymer composition and concentration, and pretilt angle effect are analyzed. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 183–192     

UV/Fe(Ⅲ)-富马酸盐体系降解对硝基苯酚

研究了在紫外光(UV)照射下,Fe(Ⅲ)-富马酸盐体系对p-硝基苯酚(PNP)的光降解反应,考察了溶液pH、Fe(Ⅲ)、富马酸盐和PNP的初始浓度对PNP降解率的影响。结果表明,UV/Fe(Ⅲ)-富马酸盐体系对PNP有光降解作用,相比于只含Fe(Ⅲ)或者富马酸盐体系,同时加入Fe(Ⅲ)与富马酸盐构成的体系在降解PNP方面有协同作用。在pH 3.0~6.0范围内,PNP的降解率随着pH和PNP初始浓度的增大而降低,而随着Fe(Ⅲ)和富马酸盐的初始浓度的增大而增大。氯仿猝灭法证实,该体系在降解PNP反应过程中产生了超氧负离子自由基;采用荧光法和异丙醇猝灭法证实了该体系在反应过程中产生了羟基自由基,同时证实了羟基自由基为PNP光降解反应的主要反应物质。     

羟甲基化木质素磺酸盐添加剂对钻井液性能的影响

为了进一步优化木质素磺酸盐作为钻井液处理剂的效能,利用其与甲醛的羟甲基化反应制备了羟甲基化木质素磺酸盐;采用红外光谱仪、X射线粉末衍射仪、扫描电镜等分析了其结构;测定了改性前后的木质素磺酸盐对钻井液流变性、降滤失性、黏土水化膨胀抑制性等性能的影响.结果显示,改性后的羟甲基化木质素磺酸盐的整体结构变化不大,但羟基数量增加,与水的相溶性增强.与木质素磺酸盐相比,羟甲基化木质素磺酸盐在室温下对基浆有较强的提黏作用,经180℃高温老化后降黏、降滤失作用有所增强,形成的泥饼厚度降低,对黏土水化膨胀的抑制作用增强.     

共振散射法测定安乃近含量

在pH=5.0的B-R缓冲溶液中,Fe(Ⅲ)与邻菲啰啉反应生成无色配合物,从而使得体系在374nm波长处产生1个较强的共振散射峰。加入安乃近(或4-甲氨基安替比林)后,其将Fe(Ⅲ)还原成Fe(Ⅱ),而生成一种橙红色配合物,使得体系在374nm(或373nm)波长处的共振散射信号减弱。在最佳实验条件下,当安乃近浓度在0.634~15.2μg/mL范围内,体系的共振散射信号△I与安乃近的浓度之间有较好的线性关系,检出限为5.75ng/mL。该方法可直接用于测定安乃近含量,回收率为100.4%~103.4%。     

孔雀石绿分子印迹表面等离子共振传感器的制备及分析应用

利用表面等离子共振(SPR)光谱,结合分子印迹技术,制备了孔雀石绿分子印迹SPR传感器,建立了检测孔雀石绿的分析方法。探讨了pH值对分子印迹膜吸附特性的影响,并在最佳pH下对其吸附选择性进行了考察。研究结果表明,与相应非印迹传感膜相比,孔雀石绿印迹传感膜对孔雀石绿具有较高的吸附选择性能。该方法测定河水及河泥中孔雀绿的线性范围为8.0×10-10~1.0×10-8 mol/L,检出限(S/N=3)分别为8.83×10-11 mol/L和1.55×10-10 mol/L,平均回收率分别为91.97%和93.88%,相对标准偏差分别为1.2%和2.1%。该方法具有简单、快速、灵敏度高、重复性好等特点,适用于河水和河泥中孔雀石绿的测定。     

两种异马来二氰基二硫烯镍(II)-取代苄基喹啉鎓盐的制备及其光谱性质和晶体结构

以甲醇为溶剂,将异马来二氰基二硫烯酸钾[K2(i-mnt)]和六水氯化镍分别与溴化4-溴苄基喹啉盐([4-BrBzQl]Br)或溴化4-硝基苄基喹啉盐([4-NO2BzQl]Br)直接反应,得到两种新的离子对配合物[4-BrBzQl]2[Ni(i-mnt)2](1)和[4-NO2BzQl]2[Ni(i-mnt)2](2);测定了其红外光谱和紫外-可见光谱,并利用X射线衍射表征了配合物1的晶体结构.结果表明,配合物[4-BrBzQl]2[Ni(i-mnt)2]为三斜晶系,P-1空间群,其每个不对称单元含半个[Ni(i-mnt)2]2-阴离子和1个[4-BrBzQl]+阳离子,晶体中的阴、阳离子通过静电作用和C-H…S、C-H…N氢键作用形成网络结构.     

水热法合成纳米氧化铜及其对盐酸异丙嗪的电化学传感研究

采用简单的水热法一步反应,制备了尺径均一的纳米氧化铜颗粒并构建了纳米氧化铜修饰电极。结果表明,该修饰电极对盐酸异丙嗪的电化学氧化有显著的电催化作用,研究了各种因素包括pH值、修饰剂用量、扫速以及共存离子等对电极响应的影响,优化了各项测试条件。该方法测定盐酸异丙嗪的线性范围为0.5~150μmol/L,检出限为1.3×10-7 mol/L,同时成功测定了药物中盐酸异丙嗪的含量。     

Ternary Sn-Ti-O Electrocatalyst Boosts the Stability and Energy Efficiency of CO2 Reduction

Simultaneously improving energy efficiency (EE) and material stability in electrochemical CO₂ conversion remains an unsolved challenge. Among a series of ternary Sn-Ti-O electrocatalysts, 3D ordered mesoporous (3DOM) Sn_0.3Ti_0.7O₂ achieves a trade-off between active-site exposure and structural stability, demonstrating up to 71.5 % half-cell EE over 200 hours, and a 94.5 % Faradaic efficiency for CO at an overpotential as low as 430 mV. DFT and X-ray absorption fine structure analyses reveal an electron density reconfiguration in the Sn-Ti-O system. A downshift of the orbital band center of Sn and a charge depletion of Ti collectively facilitate the dissociative adsorption of the desired intermediate COOH* for CO formation. It is also beneficial in maintaining a local alkaline environment to suppress H₂ and formate formation, and in stabilizing oxygen atoms to prolong durability. These findings provide a new strategy in materials design for efficient CO₂ conversion and beyond.     

Light-Driven Crawling of Molecular Crystals by Phase-Dependent Transient Elastic Lattice Deformation

The light-driven crawling of a molecular crystal that can form three phases, (α, β, and γ) is presented. Laser irradiation of the molecular crystal can generate phase-dependent transient elastic lattice deformation. The resulting elastic lattice deformation that follows scanning irradiation of a laser can actuate the different phases of molecular crystal to move with different velocity and direction. Because the γ phase has a large Young's modulus (ca. 26 GPa), a force of 0.1 μN can be generated under one laser spot. The generated force is sufficient to actuate the γ-formed molecular crystals in a wide dimensional range to move longitudinally at a velocity of about 60 μm min⁻¹, which is two orders of magnitude faster than the α and β phases.