水热辅助表面接枝印迹法制备Cd(Ⅱ)离子印迹硅胶及其性能研究

采用水热辅助表面接枝印迹技术,以Cd(Ⅱ)离子作为模板,巯基丙基三甲氧基硅烷为功能分子,环氧氯丙烷为交联剂,在硅胶表面制备出高容量的Cd(Ⅱ)离子印迹硅胶材料,利用红外光谱仪、扫描电镜、热重分析仪等进行了表征,采用平衡吸附法研究了印迹硅胶材料的吸附性能和选择识别能力。结果表明,印迹硅胶材料和非印迹硅胶材料的最大吸附量分别为42.5和22.1mg/g;印迹硅胶材料对Cd(Ⅱ)离子具有较强的选择识别能力,对Cd(Ⅱ)离子的吸附行为更符合Langmuir模型,20min即可达到吸附平衡,符合准二级动力学方程,pH值在4～8范围内,保持了较好的吸附容量;重复使用时性能较好。     

硅藻基Cd(Ⅱ)离子印迹吸附材料的构建和选择性研究

以天然活性非晶体材料硅藻为载体、巯丙基三甲氧基硅烷(MPS)为功能单体、Cd(Ⅱ)离子为模板离子、环氧氯丙烷(ECH)为交联剂,采用表面离子印迹技术制备硅藻基离子印迹复合吸附材料。利用SEM考察复合材料表面形貌的变化,利用XPS和FT-IR研究硅藻表面组构转换过程。结果表明:MPS水解后与硅藻表面活性硅羟基脱水缩合形成有效接枝,将功能基团(—SH)引入到硅藻表面;ECH与—SH经交联作用形成交联网状的印迹位点。结合XPS半定量分析,推导出MPS在硅藻表面的接枝度公式,确定了硅藻基Cd(Ⅱ)离子印迹复合吸附材料的接枝模式。MPS在硅藻表面的接枝方式是以单接枝型为主、双接枝型为辅;印迹硅藻与Cd(Ⅱ)离子间吸附作用机理是通过—SH上S原子的孤对电子与Cd的配位作用。根据选择性效果评价,制备出的硅藻基Cd(Ⅱ)离子印迹复合吸附材料对Cd(Ⅱ)离子具有选择性,且对水溶液中的Cd(Ⅱ)离子去除率从24.4%提升到97%,已具备定向去除Cd(Ⅱ)离子的能力。     

银离子注入ABS树脂抗菌性能研究

用MEVVA源将银离子注入ABS(Acrylonitrile Butadiene Styrene)树脂表面,研究在注入剂量为1.0×1016ions/cm2、注入能量由5 keV到30 keV材料的抗菌性。通过X射线光电子能谱(XPS)及拉曼(Raman)光谱对样品表面进行了表征,并测试样品的疏水性和抗菌性。结果表明:载能离子导致ABS树脂表面部分化学键断裂,并出现失氢、富碳,而银以离子形式存在其氧化物中;材料表面的接触角变大,由亲水性材料变为疏水性材料;银离子注入后材料具有良好的抗菌性能,抗菌效果随着离子注入能量的增加呈现降低趋势。     

新型分离材料硅胶表面分子印迹聚合物的制备

本文研究了一种新的基于硅胶表面修饰的分子印迹聚合物制备方法。首先在硅胶表面共价键引进硅氧烷,利用硅氧烷的端基官能团与偶氮(4'氰基戊酸)进一步反应,在硅胶表面引进偶氮引发剂。然后采用分子印迹技术,以甲基丙烯酸为功能单体和乙二醇二甲基丙烯酸酯为交联剂,在硅胶表面合成了对D苯丙氨酸具有选择性结合能力的表面分子印迹的新型分离材料。并用平衡吸附实验研究了其吸附性能。结果表明:该聚合物对D苯丙氨酸有较高的亲和性、选择性、吸附量,可用于分离领域如色谱填料、固相萃取等。     

多核磺酸基功能化离子液体催化合成叔丁基甘油醚

制备了两种多核磺酸功能化离子液体,并对其催化甘油和叔丁醇醚化反应的催化性能进行了研究。结果表明:多核磺酸功能化离子液体较市售单核磺酸离子液体具有更好的催化性能,其中1,3,5,7-四丁基磺酸-六次甲基四铵硫酸氢盐离子液体(MIL1)的催化性能最佳。在最佳实验条件下,甘油转化率超过86%,MTBG、DTBG和TTBG的选择性分别超过51%、44%和4%。     

铁(Ⅱ)离子印迹聚合物对稀土中铁的识别性能研究

通过γ-氯丙基三甲氧基硅烷的媒介,将功能大分子聚乙烯亚胺(PEI)偶合接枝到硅胶微粒表面,形成了接枝材料PEI/SiO2;以Fe2+为模板离子,乙二醇二缩水甘油醚为交联剂,对化学键合在硅胶表面的PEI大分子链进行了离子印迹,制备了Fe2+印迹材料IIP-PEI/SiO2。采用静态法研究了IIP-PEI/SiO2对Fe2+的结合特性。实验结果表明,Fe2+印迹材料IIP-PEI/SiO2对Fe2+具有强的结合亲合性与优良的识别选择性。IIP-PEI/SiO2对Fe2+的结合容量可以达到1.98mmol/g,结合行为服从Freundlich单分子层吸附。相对于Ce3+与Pr3+离子,IIP-PEI/SiO2对Fe2+离子的选择性系数分别为25.57与20.63。另外,IIP-PEI/SiO2具有良好的重复使用性能。     

离子印迹聚合物对Sc(Ⅲ)的结合识别性能研究

将功能大分子聚乙烯亚胺(polyethyleneimine,PEI)化学接枝到硅胶微粒表面,成功制得了功能接枝材料PEI/SiO2;采用表面印迹技术,以Sc3+为模板离子,乙二醇二缩水甘油醚为交联剂,对硅胶表面的PEI大分子链进行了交联,同时实现了Sc3+离子的印迹,制得了Sc3+印迹材料IIP-PEI/SiO2。采用静态法研究了IIP-PEI/SiO2对Sc3+的结合特性与识别选择性。实验结果表明,Sc3+印迹材料IIP-PEI/SiO2对Sc3+具有强的结合亲合性与优良的识别选择性。IIPPEI/SiO2对Sc3+的结合容量可以达到1.08mg/g,结合行为服从Freundlich单分子层吸附。相对于Al 3+离子和Fe3+离子,IIP-PEI/SiO2对Sc3+离子的选择性系数分别为4.21和5.73。对模拟和实际赤泥酸浸液进行了研究,实现了Sc3+的高效回收。另外,IIP-PEI/SiO2具有良好的重复使用性能。     

镉离子印迹硅胶材料的制备、表征及其吸附性能研究

采用表面接枝印迹技术,以Cd2+作为模板离子,二乙烯三胺基丙基三甲氧基硅烷为功能分子,硅胶为支撑物,环氧氯丙烷为交联剂,在硅胶表面制备了一种新型的Cd2+离子印迹硅胶材料,并利用平衡吸附法研究了印迹材料的吸附性能和选择识别能力。结果表明,最大吸附量为30.8mg/g,20min即可达到吸附平衡;当pH值在4～8范围内,印迹材料保持了较好的吸附容量;印迹材料对Cd2+离子具有较强的选择性识别能力,重复使用性能稳定。     

石墨烯基电容去离子电极材料的制备及其性能

石墨烯是2004年制备出的单层碳原子二维材料,具有比表面积大、导电性高等优点,近年来在电容去离子中作为电极材料的潜力逐渐受到关注。总结了自2009年第1篇相关文献发表以来石墨烯或其复合物(统称为石墨烯基电极材料)作为电容去离子电极材料的文献。首先总结了石墨烯基电极材料的制备技术;之后对石墨烯基电极材料的电极性能参数(比电容、比表面积、平均孔直径、导电性等)进行了归纳和比较;进一步讨论了不同石墨烯基电极材料应用于电容去离子的电吸附性能,并与其它碳电极材料作了对比;最后对石墨烯基电极材料用于电容去离子的研究方向作了展望。     

稀土-锌抗菌硅胶的制备及在硅橡胶中的应用研究

以碳酸氢钠和硅酸钠为原料,采用溶胶-凝胶法制备出含锌、钇离子的新型抗菌硅胶。通过单因素实验找出较佳的制备条件:反应时间为1h、锌离子浓度为0.8mol/L、稀土钇离子浓度为0.005mol/L。采用红外光谱、X射线衍射、扫描电镜和激光粒度分析仪等手段对材料进行表征,并通过抗菌检测(涂布平板法,菌种采用大肠杆菌)对材料的抗菌性能进行研究。结果表明:锌、钇离子的掺杂对硅胶的分子结构和化学键没有影响,且抗菌硅胶结构松散、粒度均一呈无定形态。锌-钇抗菌硅胶对大肠杆菌具有较好的杀菌效果,杀菌率可达到84%以上。将较佳条件下制备出的锌-钇抗菌硅胶添加到原橡胶中,探究了添加量对硅橡胶抗菌性能和力学性能的影响,当添加量为0.35%时,可制备出具有抗菌性,且保持橡胶本身性能的抗菌硅橡胶。     

Separation, preconcentration and determination of silver ion from water samples using silica gel modified with 2,4,6-trimorpholino-1,3,5-triazin

A new modified silica gel using 2,4,6-trimorpholino-1,3,5-triazin was used for separation, preconcentration and determination of silver ion in natural water by atomic absorption spectrometry (AAS). This new bonded silica gel was used as an effective sorbent for the solid-phase extraction (SPE) of silver ion from aqueous solutions. Experimental conditions for effective adsorption of trace levels of silver ion were optimized with respect to different experimental parameters in column process. Common coexisting ions did not interfere with the separation and determination of silver at pH 3.5 so that silver ion completely adsorbed on the column. The preconcentration factor is 130 (1 mL elution volume for a 130 mL sample volume). The relative standard deviation (R.S.D.) under optimum conditions is 3.03% (n=5). The accuracy of the method was estimated by using spring and tap water samples that were spiked with different amounts of silver ion. The adsorption isotherm of silver ion was obtained. The capacity of the sorbent at optimum conditions has been found to be 384 microg of silver per gram of sorbent.     

离子改性的聚丙烯酸除湿换热器系统性能研究

干燥剂吸附性能对除湿换热器系统的除湿性能有重要影响。本文通过改进的ASAP2020气体吸附仪和恒温恒湿箱,先后对Na+和K+改性的聚丙烯酸聚合物的水蒸气平衡吸附性能和吸附动力学特性进行了测试研究,并与硅胶相对比。研究结果表明:平衡吸附测试显示Na⁺改性的聚丙烯酸在整个相对压力区间性能优于硅胶,K⁺改性的在高相对压力区间(>0. 8)逊于硅胶;基于Polanyi吸附势理论对干燥剂吸附特征曲线进行拟合,以用于后续的除湿换热器模拟研究;动态吸附性能表明聚丙烯酸干燥剂的吸附速率均低于硅胶,但Na⁺改性的聚丙烯酸整个吸附过程的动态吸附量仍多于硅胶;通过模拟除湿换热器除湿性能,在ARI summer、ARI humid和上海夏季这3种典型室外工况下,Na⁺改性的聚丙烯酸换热器可以从待处理空气中去除更多的水分,较硅胶换热器提升49%～118%,适用于室外湿度较小的气候工况。     

Characterization of SiO2/Ag composite particles synthesized by in situ reduction and its application in electrically conductive adhesives

In the study, SiO₂/Ag composite particles with silver coating onto the surface of silica have been successfully prepared via a novel and facile approach (Oxidation–Reduction Method). In this approach, the SiO₂ particles were first modified with 3-ammoniatriethoxysilane (APTES) and glyoxalic acid (GA) through two-step reaction, the aldehyde group (CHO) were anchored onto the surfaces of silica spheres via electrostatic attraction, these [Ag(TEA)₂]⁺ ions in the solution were then reduced by the CHO and coated onto the surface of silica to obtain SiO₂/Ag composite particles. The effects of the reaction conditions on silver content and synthetic mechanism had also been discussed. The structure, morphology and optical properties of the SiO₂/Ag composite particles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV–vis spectroscopy. The results showed the surface of SiO₂ was surrounded by pure silver nanoparticles, and the silver nanoparticles had face-centered-cubic structure, the SiO₂/Ag composite particles with core–shell morphology and special optical properties. And the small content SiO₂/Ag composite particles applied in electrically conductive adhesives (ECAs) improved the electrical bulk resistivity and tensile shear strength.     

Preparation and use of chemically modified MCM-41 and silica gel as selective adsorbents for Hg(II) ions

Adsorbents for Hg(II) ion extraction were prepared using amorphous silica gel and ordered MCM-41. Grafting with 2-(3-(2-aminoethylthio)propylthio)ethanamine was used to functionalize the silica. The functionalized adsorbents were characterized by nitrogen adsorption, X-ray diffraction, 13C MAS NMR spectroscopy and thermogravimetric analysis. The adsorption properties of the modified silica gel and MCM-41 were compared using batch method. The effect of pH, stirring time, ionic strength and foreign ions were studied. The extraction of Hg(II) ions occurred rapidly with the modified MCM-41 and the optimal pH range for the extraction by the modified materials was pH 4-7. Foreign ions, especially Cl- had some effect on the extraction efficiency of the modified silica gel and the modified MCM-41. The adsorption behavior of both adsorbents could be described by a Langmuir model at 298 K, and the maximum adsorption capacity of the modified silica gel and MCM-41 at pH 3 was 0.79 and 0.70 mmol g(-1), respectively. The modified MCM-41 showed a larger Langmuir constant than that of the modified silica gel, indicating a better ability for Hg(II) ion adsorption. The results indicate that the structure of the materials affects the adsorption behavior. These materials show a potential for the application as effective and selective adsorbents for Hg(II) removal from water.     

Silica gel functionalized with 4-phenylacetophynone 4-aminobenzoylhydrazone: Synthesis of a new chelating matrix and its application as metal ion collector

The silica gel surface immobilized with 4-phenylacetophynone 4-aminobenzoylhydrazone (PAAH) after surface modification by 3-chloropropyltrimethoxysilane (CPTS). The modified silica gel was used for sorption of Cu(II), Ni(II) and Co(II) in aqueous solution. The effect of solution pH, sorption time, temperature and initial metal ion concentration onto metal ions sorption was investigated. The characteristics of the sorption process were evaluated by using the Langmuir, Freundlich and Dubinin–Radushkevich (D–R) adsorption isotherms. The sorption of metal ions onto modified silica gel correlated well with the Langmuir type adsorption isotherm and adsorption capacities were found to be 0.012, 0.014 and 0.018 mmol g⁻¹ for Cu(II), Ni(II) and Co(II) metal ions, respectively. From the D–R adsorption isotherms, it was concluded that chemical interactions and chelating effects were playing an important role in the sorption of metal ions onto modified silica gel.

Thermodynamic parameters such as the standard free energy change (ΔG)°, enthalpy change (ΔH°) and entrophy change (ΔS°) were calculated to determine the nature of sorption process. From these parameters, ΔH° were found to be endothermic values: 38.39, 18.0, and 14.7 kJ mol⁻¹ for the same sequence of divalent cations and ΔS° values were calculated to be positive for the sorption of each metal ion onto the modified silica gel. Negative ΔG° values indicated that sorption process for all metal ions were spontaneous in nature although they presented an endothermic enthalpy for the interaction, resulting in an entropically favoured process.     

Al_2O_3对稀土配合物掺杂有机改性凝胶玻璃结构及荧光性能的影响

以γ-缩水甘油氧基三甲氧基硅烷作为有机改性先驱体,采用原位合成技术,用溶胶-凝胶法制备稀土离子(Eu3+或Tb3+)、配位体β-二酮噻吩甲酰三氟丙酮或苯甲酸及协同体1,10-菲啰啉共掺的两种有机改性二氧化硅玻璃,测量它们的发射光谱和红外光谱,并进行X射线衍射分析和扫描电镜观察,探讨Al2O3的掺量对凝胶玻璃结构及性能的影响。结果表明:Al3+对稀土离子发射峰的位置没有明显的影响,并使凝胶在室温时的荧光减弱,但它能使稀土离子及原位合成的配合物在较高温度保持相对稳定,提高凝胶玻璃的热稳定性和荧光强度;在制备较实用的具有较强荧光的含稀土离子的凝胶玻璃时,要根据实际需要选取适宜掺量的Al2O3。     

多孔SiO2凝胶玻璃的制备及孔径控制

以正硅酸乙酯（ＴＥＯＳ）为原料，采用溶胶－凝胶法制备了多孔ＳｉＯ２凝胶玻璃，研究了氨水，盐酸，硝酸，氢氟酸等不同种类的催化剂对孔的影响，制备了多孔ＳｉＯ２凝胶玻璃，利用氮气吸附法对孔结构进行了分析。在透射电镜下观察了凝胶颗粒形貌。     

Fabrication of hollow silver spheres by MPTMS-functionalized hollow silica spheres as templates

In this study, we provide a strategy to prepare the hollow silver spheres by accumulating the silver nanoparticles on the surface of 3-mercaptopropyltrimethoxysilane (MPTMS)-functionalized silica as templates, which was accomplished by the chemisorption between silver nanoparticles and thiol groups. Then, the resulting hollow silver spheres were obtained through the chemical wet etching process with 10 M HF solution. In conventional method, the fabrication of hollow silver spheres from core-shell spheres was not easy due to the difficulties in retaining the shell structures during core removal. The method in this paper could overcome this limitation. The major focus of study is on understanding the mechanism of formation of the hollow silver spheres through the self-assembly behavior by chemisorption between silver nanoparticles and thiol groups. The silver-coated silica and hollow silver spheres were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), high-resolution TEM (HR-TEM), and X-ray photoelectron spectroscopy (XPS).     

Dual mechanism bifunctional polymers: Phosphinic acid ion-exchange/redox resins and the kinetics of metal-ion complexation

The detailed study of bifunctional phosphinic acid resins has recently been introduced. It has been shown that they operate through the dual mechanism of ion exchange and metal-ion reduction. A key component in the synthesis is the Friedel-Crafts catalyst used for the reaction between PCl₃ and polystyrene. We now find that the order of catalyst activity is AlCl₃ > FeCl₃ > ZnCl₂ > SnCl₄. Ferric chloride catalysis also operates by an additional redox mechanism which yields a phosphonic acid resin. The extent of loading onto phosphinic and sulfonic acid resins by zinc ions at equilibrium was studied as a function of the anion present both with and without the presence of an excess of sodium ions. Both sets of resins exchange at a comparable rate upon the introduction of macroporosity into the polystyrene support. The influence of the redox process as an additional variable in the phosphinic resin kinetics was studied with silver and mercury(II) nitrate solutions. All of the primary acid sites are oxidized after a 9-hour contact time with Ag(I) ions and a 2-hour contact time with Hg(II) ions. The mercury loading curves and the different behavior of silver, which shows more ion exchange than redox at short times while leaving a residual ion concentration on the resin irrespective of whether all of the primary acid sites have been oxidized or not, can be explained by the termolecular nature of the Ag(I) redox reaction in contrast to the bimolecular nature of the Hg(II) reaction. Studies with other ions show that the minimum metal-ion reduction potential below which no redox occurs with the phosphinic resins is probably between 0.0 and 0.3 V.     

微滴乳液聚合制备纳米SiO2/聚丙烯酸酯复合材料

在硅溶胶中加入八甲基环四硅氧烷(D4)和偶联剂γ-(2,3-环氧丙氧) 丙基三甲氧基硅烷(KH560),以十二烷基苯磺酸(DBSA)催化D4的开环聚合,借助超声强化聚二甲基硅氧烷(PDMS)和偶联剂对硅溶胶的表面改性。将改性硅溶胶及其混合物分散在甲基丙烯酸甲酯(MMA)和丙烯酸丁酯(BA)的混合单体中,实施微滴乳液聚合,制备SiO₂/聚丙烯酸酯纳米复合材料。硅溶胶改性阶段的催化剂中和后成为后续微滴乳液聚合的乳化剂,而伴生的PDMS成为有效抑制单体珠滴Ostwald 熟化的超疏水剂。采用FTIR、TGA、TEM、马尔文纳米粒度仪、水接触角等测试方法对改性纳米粒、复合胶乳和胶乳薄膜进行表征。结果表明,PDMS和偶联剂在SiO₂表面形成了共价键合和包覆,且伴生的PDMS改善了复合胶乳薄膜的表面疏水性,复合粒子是聚合物基体为壳、SiO₂纳米颗粒呈海岛分散的 (多)核-壳结构形态,SiO₂占单体质量分数为3%时,平均粒径约98 nm。