基于短孔道Zr-Ce-SBA-15固定胃蛋白酶的活性生物催化剂

在不外加无机酸的条件下, 通过水热合成法制备了短孔道六方板状有序介孔材料Zr-Ce-SBA-15 (ZCS). 以ZCS和传统SBA-15为载体对胃蛋白酶进行固定, 并利用N-(2-氨乙基)-3-氨丙基三甲氧基硅烷(AAPTS)对酶固定化材料进行功能化, 以缩小开口孔径从而减少酶泄漏. 采用小角X射线衍射、扫描电镜、透射电镜、氮气吸附和红外光谱对样品进行结构表征. 结果表明, 胃蛋白酶成功固定到介孔孔道中, AAPTS嫁接到材料中且没有破坏介孔结构. 固定化实验表明相比于SBA-15, ZCS对胃蛋白酶具有较快的吸附速度和较强的固定化能力(最大负载量为257.9 mg/g), 短孔道材料能有效地促进分子的扩散传递. 催化活性测定以牛血红蛋白为探针物, 与游离酶相比, 固定酶对牛血红蛋白保持着稳定的活性.     

巯基功能化介孔氧化硅的合成及其对Pb(Ⅱ)的吸附

采用直接模板法,以三嵌段共聚物P123作为模板剂,酸性条件下制备出了具有规则孔道结构的介孔氧化硅.用有机硅烷MPTMS对其进行后续功能化,引入了对Pb2 离子有吸附能力的巯基基团.通过HRTEM、FTIR和N2吸附脱附等测试手段对功能化前后氧化硅的结构进行表征,结果表明,巯基功能团接枝在介孔氧化硅孔道内壁.吸附实验结果显示,巯基功能化氧化硅对水中Pb(Ⅱ)离子具有选择吸附性.当铅与铜、镉离子摩尔比为1:5时,巯基功能化材料对其吸附的分配系数之比分别为KdPb2 /KdCu2 =13.1和KdPb2 /KdCd2 =9.2.在Cu2 、Cd2 离子摩尔浓度相同时,此功能化介孔材料对Cd2 的吸附能力大于对Cu2 的吸附能力.     

功能化SBA-15介孔材料的制备及其吸附性能研究

硅基介孔材料因其特有的特性,被用于去除废水中重金属离子的吸附剂.为了提高对目标污染物的吸附容量, 本文采用一步法和两步法制备了氨基或巯基功能化SBA-15介孔材料,利用傅里叶红外光谱仪、场发射扫描电镜、X射线衍射仪和氮气吸附脱附表征测试了材料的化学组成、微观形貌和物相结构.测试结果显示经功能化处理后的样品成功地接枝氨基或巯基功能基团.研究发现,经功能化处理后,材料的骨架结构及介孔孔道均未被破坏,但有序性下降且出现少许团聚,物性参数也有一定程度下降,功能化材料对Zn²⁺、Pb²⁺、Cr³⁺和Cu²⁺的吸附率均有大幅度提高.经氨基或巯基功能化后,SBA-15介孔材料对水体中重金属离子的吸附率有很大提高,但一步法制备的功能化硅基介孔材料因模板剂去除不彻底而影响了对重金属离子的吸附效率,两步法制备的功能化硅基介孔材料对重金属离子的吸附效果更好,说明本文的功能化硅基介孔材料工艺是可行有效的,但两步法合成的功能化介孔材料具有更好的吸附效果.     

粉煤灰合成介孔分子筛SBA-15对稀土元素的吸附

以粉煤灰为原料、EO_(20)PO_(70)EO_(20)(P123)为模板剂,采用碱溶-水热法制备出高度有序的介孔分子筛SBA-15;以3-氨丙基三乙氧基硅烷(APTES)为修饰剂对SBA-15进行表面氨基化。再用膦酰基乙酸(PAA)、二乙烯三胺五乙酸二酐(DTPADA)对其进一步功能化,合成材料PAA-SBA-15和DTPADA-SBA-15。通过小角XRD衍射、全反射红外、和氮气吸附对材料进行了分析和表征,并研究了材料对稀土元素Yb、Ho的吸附性能。结果表明,经过不同官能团修饰的材料依然具有良好的介孔结构;此外吸附结果表明,在pH值为6时,PAA-SBA-15对Ho、Yb的吸附效率分别为89.8%,94.4%;在pH值为2时,DTPADA-SBA-15对Ho、Yb的吸附效率为92.6%,89.0%。     

树枝状硅基纳米粒子对重金属去除研究进展

树枝状介孔二氧化硅纳米粒子(DMSNs)独特的三维中心辐射状孔道结构使其具有出色的比表面积和孔体积,表面硅羟基官能团可作为功能化活性位点。已有研究表明,DMSNs基新型吸附剂材料能够替代传统二氧化硅材料(如MCM-41和SBA-15),对重金属离子具有优异的去除作用。综述总结了DMSNs基新型吸附剂材料的功能化方法,比较了其和功能化MCM-41或SBA-15对不同重金属离子(Pb²⁺、Cr⁶⁺、Hg²⁺等)和放射性金属离子(U(Ⅵ)、Th(Ⅳ)等)的吸附性能,以期为设计具有优越重金属离子去除能力的DMSNs基新型吸附材料提供理论指导。     

以嵌段共聚物为结构导向剂的SBA-15和SBA-16的合成及表征

利用嵌段共聚物P123和F127分别在强酸性条件下合成了两种结构不同的介孔氧化硅材料:一维直孔道六方相的SBA-15和三维立方相的SBA-16,并通过XRD、N₂吸附-脱附、HTEM等手段对材料进行了研究。结果表明:商品化的嵌段共聚物作为结构导向剂合成的介孔氧化硅材料SBA-15和SBA-16孔道规整有序,比表面积分别达到765m²·g^-1和930m²·g^-1,相应的最可几孔径分别为6.46nm和3.92nm,这有利于介孔材料向经济实用方向发展。     

无外加酸体系中AlSBA-15为模板,有序介孔炭材料CMK-3的合成与表征

在无外加酸体系中改变晶化温度合成Al SBA-15介孔材料,并以此为刚性模板,蔗糖为碳源,合成出一系列具有不同孔结构的有序介孔炭材料CMK-3,系统考察晶化温度对Al SBA-15和其反相复制结构CMK-3孔道结构的影响。结果显示在无外加酸合成体系中改变晶化温度可对Al SBA-15的孔道结构进行有效调控,通过结构复制技术可制备出具有不同结构的CM K-3。控制刚性模板Al SBA-15的晶化温度为90℃,所得介孔炭材料CM K-3(CM K-3(90))结构最佳,除介孔排列高度有序外,还具有高比表面积(1688 m2·g-1)和大孔容(0.95 cm3·g-1)。另外,对CMK-3的微孔性质与刚性模板孔壁中的次级介孔结构的内在联系进行研究,发现调变刚性模板的晶化温度可以有效改善有序介孔炭材料CMK-3的结构性质。     

巯基改性SBA-15的制备及其对Cr6+的吸附

环境中存在的重金属铬对人体健康有严重的危害, 本研究采用水热共缩聚法制备了一种对Cr ⁶⁺有较高吸附能力的介孔材料SBA-15-SH。经红外光谱证实, 通过使用改性硅源3-巯丙基三甲氧基硅烷, 对SBA-15成功实现了巯基改性。经扫描电子显微镜(SEM)和透射电子显微镜(TEM)观察, 所制备的材料呈棒状, 具有均匀的孔道结构, 孔径约为7 nm。将制备材料用于重金属Cr ⁶⁺的吸附, 研究了吸附时间、环境温度、Cr ⁶⁺溶液pH和初始浓度以及吸附剂用量对吸附剂吸附性能的影响。研究表明: 该材料吸附Cr ⁶⁺的平衡吸附时间约10 min, 吸附过程符合Langmuir方程与伪二级动力学模型。当Cr ⁶⁺溶液pH为4.0、吸附温度在25~45 ℃时, 介孔材料SBA-15-SH对Cr ⁶⁺吸附量最大, 达到6.85 mg/g。将本方法用于自来水和工业废水中Cr ⁶⁺的吸附, 回收率介于95%~105%之间。     

复合介孔材料的结构与催化性能

以三嵌段共聚物P123为模板剂、正硅酸乙酯为硅源,在强酸和水热条件下合成了介孔分子筛SBA-15,用胺丙基三乙氧基硅烷对分子筛进行功能化。运用X射线衍射、傅里叶红外光谱,N_2吸附-脱附以及透射电子显微镜等手段对功能化前后的介孔分子筛进行了表征。以甘氨酸法制备草甘膦工艺为模型反应进行的催化性能分析表明:该介孔分子筛对该反应具有较高的催化性能。     

镧(Ⅲ)对SBA-15分子筛改性研究

借助水热法,利用三嵌段共聚物聚(1,2-亚乙基二醇)-嵌段-聚(丙二醇)-嵌段-聚(1,2-亚乙基二醇)为模板剂,正硅酸四乙酯为硅源,强酸性条件下制备了分子筛SBA-15.分别以水及水+乙醇为介质采用LaCl₃溶液与煅烧的主体材料SBA-15分子筛固-液相交换法,制备了La-(SBA-15)复合材料.利用化学分析、粉末XRD、N₂吸附技术、IR评价了制备方法的有效性及对SBA-15分子筛孔结构的影响.结果表明,镧已并入SBA-15分子筛中,SBA-15内表面上的硅羟基团是镧进入的主要位置,部分客体在分子筛孔道内.制得的材料La-(SBA-15)保持高度有序的介孔二维六角结构,不改变载体SBA-15的介孔孔道结构.此外,考察了La-(SBA-15)产物的发光现象.     

Synthesis and characterization of poly(ionic liquid)-grafted silica hybrid materials through surface radical chain-transfer polymerization and aqueous anion-exchange

Poly(ionic liquid)-grafted silica materials were firstly synthesized by polymerization of 1-vinyl-3-butylimidazolium bromide as a new ionic liquid monomer on mercaptopropylated silica by surface radical chain-transfer polymerization. The bromide counterion was exchanged with three other inorganic anions including tetrafluoroborate, hexafluorophosphate, and trifuoromethanesulfonate through simple aqueous anion-exchange reaction. The obtained poly(ionic liquid)-grafted silica materials were characterized by elemental analysis, infrared spectra, thermogravimetric analysis, and X-ray fluorescence. The wettabilities of the materials with different counterions were verified by static water contact angle measurement. This kind of new materials may have some potential in applied fields such as used as a catalyst, an extractant, a chromatographic stationary phase, etc.     

Preparation of Nano-structured LiFe_xMn_(1-x)PO_4(x=0,0.2,0.4) by Reflux Method and Research on the Influences of Fe(Ⅱ) Substitution

Nano structured LiFexMn1-xPO4(x=0,0.2,0.4) materials were successfully prepared by one-step reflux method in a water/PEG400 mixed solvent, and were coated by carbon using glucose as the precursor. The materials were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The electrochemical properties of the materials were investigated by galvanostatic cycling, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It was found that the materials consisted of nanorods with a diameter of 50 nm and a length of 500 nm. Galvanostatic cycling showed that the capacity of LiMnPO 4 could be largely increased by Fe2+ substitution. At a current rate of C/20, the capacity of the three samples (x=0,0.2,0.4) were 47, 107 and 150 mA·h·g-1 , respectively. CV result showed that the Fe2+ substitution could decrease the polarization during charging/discharging, accelerating the electrochemical process. EIS result showed that the Fe2+ substitution could decrease the charge transfer resistance between the electrode and electrolyte,     

微胶囊对微胶囊/环氧树脂复合材料增韧作用

使用脲醛(Urea-formaldehyde)树脂-环氧树脂微胶囊(E-51)和三聚氰胺-尿素-甲醛共缩聚树脂 (Melamine-urea-formaldehyde)-环氧树脂微胶囊(E-51)制备微胶囊/环氧树脂复合材料样品。对其力学性能进行了测试, 并对复合材料的断面形貌进行了观察, 研究了微胶囊对微胶囊/环氧树脂复合材料力学性能的影响。结果表明: 随着微胶囊用量的增加, 复合材料拉伸强度和弯曲强度有所降低; 微胶囊质量分数小于2%时, 复合材料断裂伸长率和断裂弯曲应变有所提高; 大于2%时复合材料断裂伸长率和断裂弯曲应变下降。微胶囊对环氧树脂有增韧效果, 微胶囊表面越粗糙, 粒径越小, 增韧效果越明显。在裂纹扩展区, 大部分微胶囊破裂, 裂纹终止区, 大部分微胶囊剥离。      

S/O型可逆热变色微胶囊的制备与性能

为改善无机热变色材料的可逆性能,采用油相相分离法,以无机变色颜料镍的化合物为芯材,乙基纤维素(EC)为壳材料,环己烷(HC)为溶剂,制备了S/O型可逆热变色微胶囊,并研究了微胶囊的结构、热稳定性和变色性能等。结果表明,S/O型可逆热变色微胶囊提高了芯材的热变色性能,具有良好的包裹和较强的保护作用。     

尿素-过氧化氢混合模板法合成介孔二氧化硅

以尿素-过氧化氢为混合模板、正硅酸乙酯为硅源,在酸性条件下,通过溶胶-凝胶过程合成二氧化硅介孔材料。采用煅烧法除去模板剂,用红外光谱、XRD、N2吸附-脱附、HRTEM等分析测试手段对介孔材料的结构和形态进行了表征。结果表明:与以尿素为单一模板相比,采用混合模板剂所合成介孔材料为蠕虫状,孔径分布基本保持不变、比表面积相近(分别为445、431m2/g)、孔径(分别为7.04、8.11nm)和孔体积(分别为0.783、0.874cm3/g)明显增大。     

Novel heterocyclic based blue and green emissive materials for opto-electronics

Two different novel heterocyclic compounds namely 2,5-bis(1,3-diphenyl-4,5-dihydro-1H-pyrazol-5-yl)thiophene (Material I) and 2,5-bis(3-(naphthalen-1-yl)-1-phenyl-4,5-dihydro-1H-pyrazol-5-yl)thiophene (Material II) were designed, synthesized and characterized by spectral methods. The synthesized materials were confirmed by standard techniques such as FT-IR, ¹H NMR and elemental analysis. Physical properties include thermal, surface morphology of the materials were explained from TGA, DSC and SEM analysis. Optical properties such as absorption, emission, solvent effect have been investigated by UV–Visible and fluorescence spectrophotometers. The blue and green emission of the materials was confirmed by using UV light as well as fluorescence spectrophotometers. Bandgap energies of these materials were obtained by both experimental and theoretical calculation from of cyclic voltammetry, UV–Visible spectrophotometer and DFT calculation. I–V characteristic analysis used to determine the threshold voltage (V_on) of the two materials. The obtained results of the materials have promising to be applicable for opto-electronic applications.     

One-pot synthesis of supported-nanoparticle materials in ionic liquid solvents

Highly porous supported-nanoparticle materials were synthesized by a rational method involving the encapsulation of poly(vinylpyrrolidone) (PVP)-stabilized Au nanoparticles into titania xerogels employing room temperature ionic liquids (1-butyl-3-methylimidazolium hexaflurophosphate, [BMIM]PF₆) as a medium followed by solvent extraction of the ionic liquid and calcination of the materials. The materials were thoroughly characterized by TEM, nitrogen adsorption-desorption isotherms, and XRD. After calcinations at 350 °C, the Au-titania system resulted in the formation of a highly mesoporous materials with BET surface areas of 200 m²/g and average pore sizes of 3-5 nm. These materials can find potential applications in catalysis and photocatalysis.     

Poly(methyl methacrylate)–titania hybrid materials by sol–gel processing

Sol–gel derived poly(methyl methacrylate)–titania hybrid materials were synthesized by using acrylic acid or allyl acetylacetone (3-allyl-2,4-pentanedione) as coupling agent. Titanium butoxide modified with acrylic acid (or titanium isopropoxide modified with allyl acetylacetone) was hydrolysed to produce a titania network, and then poly(methyl methacrylate) (PMMA) chains, formed in situ through a radical polymerization, were chemically bonded to the forming titania network to synthesize a hybrid material. Transparent hybrid materials with different contents of titania were achieved. With increase of the titania content, the colours of the products changed from yellow to dark red. The synthesis process was investigated step by step by using Fourier transform–infrared spectroscopy, and the experimental results demonstrated that acrylate or acetylacetonato groups bound to titanium remain in the final hybrid materials. The thermal stability of the hybrid materials was considerably improved relative to pure PMMA. Field emission scanning electron microscopy analyses showed the hybrid materials are porous and pore diameters vary from 10–100 nm. The hybrid materials using allyl acetylacetone as coupling agent exhibited a thermochromic effect that neither pure PMMA nor titania exhibit. This revised version was published online in November 2006 with corrections to the Cover Date.     

CeO2-ZrO2-PMMA杂化材料的制备与表征

以非离子表面活性剂(嵌段聚合物P123)为模板剂,ZrOCl2.8H2O和Ce(NO3)3.6H2O为原料,运用水热合成法合成出稀土金属氧化物CeO2-ZrO2固溶体多孔结构材料,选择硅烷偶联剂KH570对其表面进行改性后采用悬浮聚合法制备出CeO2-ZrO2-PMMA杂化材料。利用X射线衍射(XRD),N2吸附-脱附,红外光谱,扫描电镜对材料的结构和形态进行了表征,对CeO2-ZrO2-PMMA杂化材料的热性能进行了测定。结果表明CeO2-ZrO2固熔体的比表面积达到125.8724m2/g,CeO2-ZrO2-PMMA杂化材料表面呈一定的疏松结构,热分解温度为366℃,高于纯PMMA的热分解温度,拥有较好的耐热性和抗热震性能。     

采用不同钛源合成介孔钛硅催化材料的研究

利用聚氧乙烯-聚氧丙烯-聚氧乙烯三嵌段共聚物(P123)作为结构导向剂,用氯化钾调控材料的形貌,以1,3,5-三甲苯(TMB)为分子筛的扩孔剂,钛酸正丁酯和四氯化钛作为不同的钛源,原位一步法合成出Ti-SBA-15分子筛。在高温煅烧除去模板剂之后,利用X射线衍射、紫外-可见漫反射光谱、红外光谱、扫描电镜以及N2吸附-脱附曲线对合成的介孔材料进行表征。结果表明:合成的介孔钛硅材料具有有序的孔道结构,钛在SBA-15的孔道内,钛在硅中的分散好。以钛酸丁酯为钛源合成的Ti-SBA-15呈规则的球形,平均直径为3.0μm;四氯化钛为钛源合成的Ti-SBA-15没有规则的形状,大小也不均一。