介孔硅复合氧化石墨烯多孔材料的制备及其CO2吸附性能研究

以P123为模板剂,以TEOS为硅源,以氧化石墨烯为复合组分,采用溶胶-凝胶法和自组装法制备了具有较大比表面积的介孔硅复合氧化石墨烯三维多孔材料（MSM/GOs）,进一步通过物理浸渍聚乙烯亚胺（PEI）制备了固态胺吸附材料。利用扫描电子显微镜（SEM）、氮气吸附-脱附曲线、元素分析等方法表征复合材料的结构和形貌,研究了氧化石墨烯添加量对材料的比表面积和胺化效果的影响以及吸附温度对其吸附CO₂性能的影响。研究结果表明,氧化石墨烯的引入能显著提高介孔硅复合氧化石墨烯多孔材料的比表面积,当GO添加量为4.5wt%时,其比表面积可高达841m²/g。高的比表面积有利于提高材料的氨基含量。在30wt%PEI的物理浸渍胺化后,MSM/GO-4.5@30%PEI拥有最大含氮量（9.59wt%）和CO₂吸附量（1.70mmol/g）。得益于良好的多孔基体和有机胺的均匀分布,MSM/GO-4.5@30%PEI在不同温度下的吸附量较稳定,循环再生吸附后仍能保持初始吸附量的80%。动力学研究表明,准一级模型和Avrami模型均能较好地拟合其吸...     

多孔氧化物块体材料的制备及其对重金属离子吸附研究进展

目前去除重金属离子的方法较多,其中吸附法因操作简单、经济性好而被广泛使用。多孔氧化物块体材料作为新兴的吸附材料具有比表面积高、机械强度高及可回收性好等特点,但吸附选择性差以及孔结构单一的缺陷限制了其在水体重金属处理中的应用。本文详细叙述了多孔氧化物块体材料的多种制备方法,并分别讨论了各方法的优势及其不足。介绍了近几年研究较多的多孔氧化物块体材料及其制备方法与特性。最后,对多孔氧化物块体材料对 Pb、Cd及 Cr等重金属离子吸附性能的影响因素及改善措施方面进行了总结分析,并指出多种材料的复合、材料表面的接枝改性及分级多孔结构的构建会增强对重金属离子的吸附性能。期望本文为多孔氧化物块体材料的制备及其在重金属离子吸附方面的应用提供参考。     

交联聚苯乙烯孔结构对氯甲基化的影响

苯乙烯、二乙烯苯在致孔剂存在下进行悬浮聚合反应制得大孔交联聚苯乙烯,然后进行氯甲基化反应和付氏交联反应,制备了一系列吸附树脂,分别测定了它们的比表面积、孔容、平均孔径等结构性能。实验结果表明,共聚体的交联度、致孔剂的种类和用量对吸附树脂的孔结构性能有明显的影响。     

缩醛度与孔隙结构对PVF多孔材料吸水性能与力学性能的影响

采用机械搅拌表面活性剂成孔方法制备了聚乙烯醇缩甲醛(PVF)多孔材料,研究了甲醛(HCHO)与表面活性剂十二烷基硫酸钠(SDS)用量对缩醛度与孔隙结构变化的影响,探讨了缩醛度和孔隙结构变化对PVF多孔材料力学性能与吸水性能产生影响的机理.研究认为,缩醛度的提高会引起PVF的亲水性、交联密度、临近分子链间隙、硬段比例、范德华力的改变,这些变化对PVF多孔材料的拉伸强度、断裂伸长率、吸水速率以及吸水率产生影响;孔隙结构的变化导致PVF内毛细管数量、孔的比表面积、持水能力以及相对密度和应力集中改变,进而引起PVF多孔材料的力学性能与吸水性能性能发生相应改变.通过控制缩醛度与孔隙结构可获得吸水性能和力学使用性能良好的PVF多孔材料,吸水率最高可达1627％,湿态下PVF多孔材料具有良好回弹性且质地柔软.     

中国离子交换与吸附科学技术文摘(1986年)

苯乙烯、二乙烯苯在致孔剂存在下进行悬浮聚合反应制得大孔交联聚苯乙烯,然后进行氯甲基化反应和付氏交联反应,制备了一系列吸附树脂,分别测定了它们的比表面积、孔容、平均孔径等结构性能。实测结果表明,共聚体的交联度、致孔剂的种类和用量对吸附树脂的孔结构性能有明显的影响。     

碳热还原温度对耐高温纤维增强碳化硅多孔材料组织结构的影响

本研究目的是开发一种耐高温纤维增强碳化硅多孔块状材料。以纤维增强间苯二酚-甲醛/氧化硅复合气凝胶为前驱体,经过1 300~1 500℃碳热还原制备了纤维增强碳化硅多孔材料。采用XRD、SEM、TEM、氮气吸附孔结构分析仪和压汞仪对纤维增强碳化硅多孔材料的物相组成、微观形貌和孔结构进行了表征,结果表明:纤维增强碳化硅多孔材料由β-Si C和莫来石纤维组成,随着碳热还原温度的升高,样品中的Si C纳米晶颗粒团聚成大块,最终在1 500℃生成Si C晶须,升高碳热还原温度会导致样品中大孔的增多和纳米孔的消失以及比表面积的降低。热分析结果表明纤维增强碳化硅多孔材料在空气中的耐温性高达1 300℃。纤维增强碳化硅多孔材料的密度为0.330~0.345 g·cm-3,孔隙率在89%以上,室温下热导率为0.06~0.07 W·m-1·K-1。     

碳热还原温度对耐高温纤维增强碳化硅多孔材料组织结构的影响（英文）

本研究目的是开发一种耐高温纤维增强碳化硅多孔块状材料。以纤维增强间苯二酚-甲醛/氧化硅复合气凝胶为前驱体,经过1 300~1 500℃碳热还原制备了纤维增强碳化硅多孔材料。采用XRD、SEM、TEM、氮气吸附孔结构分析仪和压汞仪对纤维增强碳化硅多孔材料的物相组成、微观形貌和孔结构进行了表征,结果表明:纤维增强碳化硅多孔材料由β-Si C和莫来石纤维组成,随着碳热还原温度的升高,样品中的Si C纳米晶颗粒团聚成大块,最终在1 500℃生成Si C晶须,升高碳热还原温度会导致样品中大孔的增多和纳米孔的消失以及比表面积的降低。热分析结果表明纤维增强碳化硅多孔材料在空气中的耐温性高达1 300℃。纤维增强碳化硅多孔材料的密度为0.330~0.345 g·cm-3,孔隙率在89%以上,室温下热导率为0.06~0.07 W·m-1·K-1。     

多模板分子印迹三聚氰胺-间苯二酚-甲醛树脂的水相制备及应用

以新烟碱农药噻虫嗪和氯噻啉为模板,纳米二氧化硅为载体,间苯二酚和三聚氰胺为双功能单体,甲醛和乙腈分别为交联剂和致孔剂,在水相中制备了分子印迹树脂。通过扫描电镜、红外光谱、热重分析、氮气吸附/解吸和等温吸附平衡实验等对制备的分子印迹树脂进行表征和性能评价。结果表明,分子印迹树脂对噻虫嗪和氯噻啉具有选择性吸附能力,其最大吸附容量分别为15.68μg/mg和28.17μg/mg。以制备的分子印迹树脂为吸附材料,用于番茄浸提液中噻虫嗪、氯噻啉的加标回收实验,回收率为81.7%～95.0%,相对标准偏差(RSD)小于5%。     

离子交换树脂支载的加氢催化剂的制备及在乙二醇精制中的应用

制备了一种离子交换树脂支载的Ni-B非晶态合金催化剂,对催化剂形态及孔结构等进行了表征;将该催化剂用于催化加氢法降低乙二醇中甲醛含量的实验,考察了反应温度、乙二醇空速和压力对该催化剂催化条件下甲醛去除率的影响。结果表明,Ni-B分散在树脂载体表面和内部的孔中,催化剂孔径约20nm,属于介孔范围;在反应温度353K、乙二醇液时空速3h-1、压力0.5MPa条件下,催化剂连续运行500h,乙二醇中甲醛含量由45μg/g降低至3μg/g以下,甲醛去除率达到95%。     

复合介孔二氧化硅膜的制备及应用

复合介孔二氧化硅膜是近十年来发展起来的一种具有独特孔中孔结构的新型膜材料。该材料以多孔膜（无机多孔膜或者有机多孔膜）为硬模板,以表面活性剂为结构导向剂,通过溶胶-凝胶等方法将介孔二氧化硅材料组装在多孔膜的孔道中制备而成。由于其具有不同于传统介孔二氧化硅膜材料的一些独特结构和性能,并在分离、吸附和催化等领域具有广泛的应用前景,引起了人们广泛的关注。本文主要就复合介孔二氧化硅膜的制备方法,特别是近几年内其在纳滤、纳米材料的模板合成、酶的固定、传感器、反应器以及药物释放等方面最新的应用研究进展进行论述,同时对这类新型的复合介孔二氧化硅膜材料在合成和应用方面存在的问题进行了分析和总结,并对其发展前景作了展望。     

Investigation into adsorption mechanisms of sulfonamides onto porous adsorbents

The presence of sulfonamide antibiotics in aquatic environments poses potential ecological risks and dangers to human health. In this study, porous resins as adsorbents for the removal of two sulfonamides, sulfadiazine and sulfadimidine, from aqueous solutions were evaluated. Activated carbon F-400 was included as a comparative adsorbent. Despite the different surface properties and pore structures of the three resins, similar patterns of pH-dependent adsorption were observed, implying the importance of sulfonamide molecular forms to the adsorption process on the resins. Sulfonamide adsorption to the three resins exhibited different ionic strengths and temperature dependence consistent with sulfonamide speciation and the corresponding adsorption mechanism. Adsorption of sulfadiazine to F-400 was relatively insensitive to pH and ionic strength as micropore-filling mainly contributed to adsorption. The adsorption mechanism of sulfadiazine to the hypercrosslinked resin MN-200 was similar to that of the macroporous resin XAD-4 at lower pH values, whereas it was almost identical to the aminated resin MN-150 at higher pH. This work provided an understanding of adsorption behavior and mechanism of sulfonamide antibiotics on different adsorbents and should result in more effective applications of porous resin for antibiotics removal from industrial wastewater.     

水热提质对褐煤理化结构及复吸水特性的影响

选取云南昭通褐煤进行了水热提质处理,依托傅里叶变换红外光谱技术和氮气等温吸附模型分析研究了不同提质温度(150-300℃)下煤样表面含氧官能团和孔隙结构的演化行为,考察了复吸水特性的变化规律。结果表明,随着提质温度的不断升高,主要亲水性含氧官能团(-OH、-COOH、C=O)不断减少;煤样的孔隙结构发生显著改变,比表面积和总孔容积先增后减,在250-300℃水热条件下有焦油产生;受理化结构协同影响的复吸水特性得到了有效遏制,复吸水率随着提质温度的升高不断下降;对提质褐煤进行储存时,环境湿度是影响褐煤复吸水的关键因素,高温水热、低温低湿度储存更能提高褐煤的提质效果。     

聚甲基丙烯酸羟乙酯树脂对胆红素的吸附研究

本文通过水相悬浮聚合制备了大孔交联聚甲基丙烯酸羟乙酯（PHEMA）树脂，研究了PHEMA树脂以及用乙醇胺功能基化后的PHEMA树脂对胆红素的吸附性能。结果表明，PHEMA树脂对胆红素的吸附性能受树脂孔结构，吸附温度，离子强度以及溶液中白蛋白的影响。该类吸附剂对胆红素有良好的吸附性能，其中用乙醇胺功能基化的树脂表现出更好的吸附能力。     

原位合成的活性脲醛树脂作为模板剂制备二氧化硅介孔材料

利用酸性条件下正硅酸乙酯的水解和脲醛树脂的聚合反应同时一步原位进行的方法合成了二氧化硅复合粉体(包括核壳微球结构和网状结构)和块体凝胶材料. 液氮吸附BET分析结果证明复合材料焙烧后得到的二氧化硅孔径分布均匀, 大小在介孔范围内. 改变反应性单体尿素. 甲醛及正硅酸乙酯等的初始浓度可对二氧化硅块体材料的孔径大小进行调节. 扫描电子显微镜观测结果显示, 随着原料单体初始浓度的变化复合粉体材料的微米级形貌可以是多孔网状结构或核壳结构. 从红外光谱和差热分析的结果推测, 高甲醛/尿素摩尔比[n(甲醛)∶n(尿素)≥2]条件下形成的支链脲醛树脂可作为块体二氧化硅理想的孔结构导向剂.     

Effect of Pore Size Distribution and Amination on Adsorption Capacities of Polymeric Adsorbents

Polymeric adsorbents with different properties were synthesized via suspension polymerization. Equilibrium and kinetics experiments were then performed to verify the adsorption capacities of the resins for molecules of various sizes. The adsorption of small molecules reached equilibrium more quickly than the adsorption of large molecules. Furthermore, the resins with small pores are easy to lower their adsorption capacities for large molecules because of the pore blockage effect. After amination, the specific surface areas of the resins decreased. The average pore diameter decreased when the resin was modified with either primary or tertiary amines, but the pore diameter increased when the resin was modified with secondary amines. The phenol adsorption capacities of the amine-modified resins were reduced because of the decreased specific area. The amine-modified resins could more efficiently adsorb reactive brilliant blue 4 owing to the presence of polar functional groups.     

Synthesis and Characterization of Melamine Formaldehyde Resins for Decorative Paper Applications

Melamine‐formaldehyde (MF) resins of improved environmental compatibility were synthesized at different molar ratios, temperature and pH. Five molar ratios of melamine and formaldehyde: 35:65, 36.5:63.5, 38.3:61.7, 41.1:58.9 and 42.4:58.6 were used to synthesize the corresponding resins. The prepared samples were characterized by using molecular weight determination viscometery, field emission scanning electron microscopy and thermogravimetric analysis. It was noticed that the solid content in the resin increases with an increase in pH. The maximum percentage of the solid content (51 %) was obtained for pH of 8.5 and temperature range of 95–98 ^oC. The refractive index of the final product was found increasing with an increase of melamine concentration in the resin. A similar trend was noticed in molecular weight of the resins with an increase in monomer yield. The maximum molecular weight of 114218 was obtained from the sample synthesized with MF molar ratio of 42.4:58.6.     

丙烯酸酯树脂对泰乐菌素的吸附

通过调节单体、交联剂和致孔剂的种类及数量合成了一系列具有不同孔结构的丙烯酸酯树脂,并从中选出具有典型吸附差异的2种树脂,拥有适合的孔分布结构的三羟甲基丙烷三甲基丙烯酸甲酯(TRIM)聚合树脂(1#)和含酰胺基的三烯丙基异氰尿酸酯(TAIC)与TRIM共聚树脂(5#),与商业化大孔丙烯酸酯树脂XAD-7作比较,研究了丙烯酸酯树脂对泰乐菌素的吸附行为和机理。结果表明,树脂1#表现出了对泰乐菌素有最高的吸附量。3种吸附剂的吸附量随溶液pH值的升高呈增加趋势。吸附剂的吸附能力随溶液NaCl离子浓度的增强而提高,而对CuCl2则呈相反趋势,这是因为疏水作用和孔径排斥效应的贡献。泰乐菌素在3种吸附剂上的吸附动力学均符合准二级动力学模型,吸附等温线符合Langmuir模型。升高温度可以使树脂吸附能力增强,可能是“溶剂替代”效应所致。     

Microemulsion‐Assisted Preparation of a Mesoporous Ferrihydrite/SiO2 Composite for the Efficient Removal of Formaldehyde from Air

Mesoporous ferrihydrite/SiO₂ composites were synthesized according to a water‐in‐oil microemulsion method and characterized by X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, thermogravimetry, nitrogen‐adsorption/desorption, and by X‐ray photoelectron spectroscopy. The as‐prepared porous ferrihydrite/SiO₂ composites showed an excellent adsorption performance for formaldehyde (HCHO) removal from indoor air at ambient temperature. It was found that the aging time during the synthesis had a significant impact on the pore structure, surface area, and HCHO adsorption of these materials. The ferrihydrite/SiO₂ composite that was aged for 3 h in the presence of tetraethyl orthosilicate (TEOS) exhibited a relatively high HCHO adsorption capacity, as well as good recyclability, which was attributed to a relatively large BET surface area, optimal pore size, a suitable Si/Fe atomic ratio, and a synergistic effect between ferrihydrite and SiO₂. This work not only demonstrates that porous ferrihydrite/SiO₂ composites can act as an efficient adsorbent toward HCHO, but suggests a new route for the rational design of cost‐effective and environmentally benign adsorbents with high performance for indoor air purification.     

Thermal behavior of modified urea–formaldehyde resins

The thermal stability of pure urea–formaldehyde resin (PR) and modified urea–formaldehyde (UF) resins with hexamethylenetetramine-HMTA (Resin 1), melamine-M (Resin 2), and ethylene urea (EU, Resin 3) including nano-SiO₂ was investigated by non-isothermal thermo-gravimetric analysis (TG), differential thermal gravimetry (DTG), and differential thermal analysis (DTA) supported by data from IR spectroscopy. Possibility of combining inorganic filler in a form of silicon dioxide with UF resins was found investigated and percentage of free formaldehyde was determined. The shift of DTG peaks to a high temperature indicates the increase of thermal stability of modified UF resin with EU (Resin 3) which is confirmed by data obtained from the FTIR study. The minimum percentage (6%) of free formaldehyde was obtained in Resin 3.     

Resin impregnation of cellulose nanofibril films facilitated by water swelling

Flexible composite films were produced by impregnating aqueous phenol formaldehyde (PF) resin into water-swollen cellulose nanofibril (CNF) films. CNF films were prepared using a pressurized filtration method in combination with freeze drying. The freeze-dried films were swollen with water then impregnated with PF resin by soaking in aqueous resin solutions of varying concentrations. Small amounts of PF slightly enhanced the tensile properties of CNF films. The formulation with the best mechanical properties was CNF/PF films with 8 wt % resin exhibiting tensile stress and toughness of 248 MPa and 26 MJ/m³, respectively. Resin concentrations higher than about 8 % resulted in composites with decreased tensile properties as compared to neat CNF films. The wet strength of the composite films was significantly higher than that of the neat CNF films. The resulting composites showed greater resistance to moisture absorption accompanied by reduced thickness swelling when soaked in water as compared to neat CNF films. The composites also showed decreased oxygen permeability at low humidity compared to neat films, but the composites did not show improved barrier properties at high humidity.