Improved simultaneous adsorption of Cu(II) and Cr(VI) of organic modified metakaolin-based geopolymer

In this paper, a metakaolin-based mesoporous geopolymer (GP-CTAB) was used as adsorbent for Cu(II) and Cr(VI) through a novel and simple synthetic route using cetyltrimethylammonium bromide (CTAB) as an organic modifier. The application of GP-CTAB for the simultaneous removal of metal anions and cations in aqueous solution was studied for the first time. The results of X-ray diffraction (XRD) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Brunauer, Emmett and Teller (BET), and Barrett, Joyner, and Halenda (BJH) methods indicate that GP-CTAB is still geopolymer even in the presence of quaternary ammonium salt cations. The material was tested to simultaneously adsorb Cu(II) and Cr(VI) from an aqueous solution. The results show that GP-CTAB can adsorb anions simultaneously without sacrificing the adsorption properties of heavy metal cations, which is superior to conventional geopolymers. The maximum theoretical adsorption capacity of GP-CTAB for Cu(II) and Cr(VI) was 108.2 mg/g and 95.3 mg/g in the binary system, respectively. It was also found that the presence of Cu(II) in the solution promoted the adsorption of Cr(VI). Given this characteristic of GP-CTAB, it has shown great application prospects in the prevention and control of heavy metal pollution.     

季铵盐改性四钛酸钾晶须及其吸附性能

通过季铵盐改性四钛酸钾晶须,应用X射线衍射分析、红外光谱,紫外-可见漫反射光谱对改性前后的四钛酸钾晶须进行表征,并初步研究了不同季铵盐改性的四钛酸钾晶须对苯酚吸附性能的研究。实验结果表明,改性前后的四钛酸钾晶须在紫外光区均有较强的光吸收,而在可见光区其吸收则较弱。改性前后四钛酸钾晶须的结构没有改变,季铵盐能够进入层状化合物的层板间,使改性后的层间距稍微增大。与改性前相比,改性后的四钛酸钾晶须对苯酚的吸附量和吸附率有了明显的提高。     

WS2纳米棒的合成及其摩擦学性能

以十六烷基三甲基溴化铵(CTAB)作为表面活性剂,利用水热合成法在180℃条件下成功制备出WS2纳米棒。用XRD、SEM、TEM和HRTEM对WS2纳米棒的结构进行表征和分析,并提出了可能的生长机理。将WS2作为润滑油添加剂加到基础油中,用CETR UMT-2摩擦磨损仪测试其摩擦学性能。结果表明:WS2纳米棒作为润滑油添加剂表现出良好的摩擦性能。     

Mechanism and Influencing Factors of Wettability Alteration of Water-Wet Sandstone Surface by CTAB

Different experimental methods including ellipsometry, zeta potential measurements, imbibition studies, and contact angle measurements were used to study the mechanism and influencing factors of wettability alteration of water-wet sandstone surface caused by CTAB (hexadecyl trimethyl ammonium bromide). Results show that when the concentration of CTAB reaches a certain level (below CMC), due to the electrostatic attraction between the positively charged head groups of CTAB and the negatively charged sandstone surface, the monolayer of CTAB is formed and hydrophobic chains of CTAB molecules are toward the aqueous phase, making the solid surface oil-wet. When the concentration of CTAB continues to increase (above CMC), due to the hydrophobic interaction, the compact bilayer of CTAB is formed and hydrophilic head groups of CTAB molecules are toward the aqueous phase, rendering the solid surface water-wet. The contact angles between the oil–water interface and the surface treated with CTAB increase with the increase of the concentration of NaCl and CaCl_2. Compared to NaCl, the inorganic salt CaCl₂ has a greater impact on the contact angle. In addition, the contact angles increase with the increase of temperature and decrease with the increase of pH value of the aqueous solution.     

Interaction of Metal–Dipeptide Complex with Ninhydrin in the Absence and Presence of Conventional CTAB Surfactant

The present work is aimed at studying the interaction between copper-glycyltyrosine [(Cu(II)-Gly-Tyr)]⁺ and ninhydrin in water and in micelles formed by cetyltrimethylammonium bromide (CTAB) using spectrophometric measurements at 80°C and pH 5.0. The order of reaction remains the same in the two systems, that is, first- and fractional-order kinetics with respect to [Cu(II)-Gly-Tyr]⁺ and [ninhydrin], respectively, in the excess of ninhydrin over [Cu(II)-Gly-Tyr]⁺. It was observed that the product formed is same in both the media. The reaction is catalyzed by CTAB, and the maximum rate enhancement is about three fold. Quantitative kinetic analysis of k_ψ–[CTAB] data was explained in terms of pseudo-phase of the micelles (assuming the association/incorporation of both the reactants at the micellar surface).     

Distinct magnetic properties of one novel type of nanoscale cobalt-iron Prussian blue analogues synthesized in microemulsion

One novel type of nanoscale cobalt-iron Prussian blue analogues (PBA) in the form of mixed nanorods and nanocubes were synthesized using cetyltrimethyl ammonium bromide (CTAB) as the surfactant in microemulsion at low temperature. The generated products were characterized by SQUID, XRD and IR techniques, etc. The effects of potassium contents, cobalt-to-iron ratios, reaction temperatures on the properties of the nanoscale cobalt-iron PBA were systematically explored. The results showed that the novel type of nanomaterials possessed distinct magnetic properties in that their coercivities were intensely dependent on cobalt-to-iron ratios and potassium contents. Furthermore, it was observed that low reaction temperature not only affected the morphologies of the products, but also had influence on their magnetic properties. Additionally, the cobalt-iron Prussian blue analogues were strongly influenced by CTAB around their surface, which led to higher Curie temperatures.     

萃取法脱除介孔磷酸镍模板剂的研究

采用溶胶-凝胶法, 以十六烷基三甲基溴化铵(CTAB)为模板剂合成了介孔磷酸镍NiPO-1和NiPO-2, 并采用溶剂萃取法进行了模板剂的脱除. 采用XRD, IR, CHN元素分析以及N₂吸附等手段研究了不同萃取剂体系、温度、萃取剂浓度及萃取次数对介孔磷酸镍(NiPOs)骨架结构和模板剂脱除率的影响. 结果表明: 在0.1 mol/L CH₃COONa/EtOH为萃取剂, 78 ℃下交换4次, 每次1 h 条件下, NiPO-1和NiPO-2中模板剂的去除率均超过97%. 萃取后介孔材料保持了较好的完整性和有序度. 萃取后样品的衍射峰强度增大, 主衍射峰d₁₀₀值亦增大主要是由于萃取过程中, 在较高的温度下NiPOs的纳米管簇结构在萃取剂中有溶胀作用|氮气吸附表明萃取后NiPO-1和NiPO-2的比表面可分别达309.5 m²•g^－1和263.9 m²•g^－1.     

高氯酸盐与十六烷基三甲基溴化铵作用的光散射

利用光散射光谱法研究了高氯酸根和阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)的作用。 在酸性条件下,高氯酸根和CTAB通过静电作用形成离子缔合物,导致体系光散射强度增强。 环境水样中的常见阴离子如Cl^-、Br^-、ClO₃^-、NO₃^-和PO₄^3-等与CTAB单独作用时其光散射强度很弱,而当它们与高氯酸根同时存在时,由于协同作用使体系散射强度发生改变。 以Cl^-为例,借助动态光散射测定,初步探讨了体系协同作用的机理。     

烷烃同系物对液膜振荡的影响

基于表面活性物质在互不相溶的油水两相间自发迁移引起油水界面电位的周期性变化的液膜振荡可用于模拟生物膜振荡,并根据生物膜对某些分子具有的独特电位振荡作为识别分子的信号,可用于化学分析。 建立了水（十六烷基三甲基溴化铵（CTAB）/正丙醇 水溶液）/油（苦味酸硝基甲烷溶液）/水（葡萄糖水溶液）液膜振荡体系。 通过向体系中添加正己烷、正辛烷、正癸烷、正十二烷、正十四烷、正十六烷、环己烷和异辛烷等物质,考察了不同碳数的烷烃同系物、烷烃同分异构体以及混合烷烃对振荡的影响。 结果表明,加入不同类型的烷烃,振荡曲线的诱导期和振荡区的振幅和频率呈现一定规律性变化,以此可进一步进行液膜振荡在烷烃同系物识别与分析中的应用研究。