微流控法制备的多孔微球对Cr(Ⅵ)的吸附性能

利用玻璃毛细管搭建单级微流控装置制备单分散水包油(O/W)乳液,以乳液为模板,紫外光照射乳液引发自由基聚合,成功制备了单分散聚(甲基丙烯酸甲酯/甲基丙烯酸二甲氨基乙酯)[P (MMA/DMAEMA)]多孔微球。微球粒径偏差系数(CV)值小于5%,单分散性良好。研究P (MMA/DMAEMA)多孔微球对Cr(Ⅵ)的吸附性能、再生吸附性能、吸附机理。结果表明,p H对微球吸附Cr(Ⅵ)有较大影响,当pH=3时,微球对Cr(Ⅵ)的吸附率达到52. 9%,循环4次后其吸附性能基本不变;微球的吸附符合准二级动力学模型,属于化学吸附;微球等温吸附符合Langmuir模型,属于单分子层吸附。     

磁性壳聚糖微球的制备及对Cr(Ⅵ)的吸附性能研究

用壳聚糖包埋磁流体,用戊二醛交联制成磁性壳聚糖微球,并用红外光谱表征其结构。用制备的磁性壳聚糖微球吸附Cr(Ⅵ)离子,考察了其对Cr(Ⅵ)离子的吸附性能;探讨了吸附时间、溶液pH值、吸附剂用量、温度、Cr(Ⅵ)起始浓度以及其他离子存在对Cr(Ⅵ)离子去除率的影响。实验结果表明,磁性壳聚糖微球吸附Cr(Ⅵ)离子的最佳条件为:吸附平衡时间40 min,最佳吸附pH值6左右,磁性壳聚糖微球用量10 mg,温度升高有利于提高磁性壳聚糖微球的吸附效率,Cr(Ⅵ)离子起始质量浓度为12μg/mL,无机盐的存在引起磁性壳聚糖微球的吸附性能降低。并且考察了吸附剂的再生性能,实验结果表明磁性壳聚糖微球具有良好的重复使用性。     

单宁微球对Cr（Ⅵ）的吸附性能

利用单宁微球吸附Cr（Ⅵ）,探讨了温度、pH值、Cr（Ⅵ）初始质量浓度等因素对单宁微球吸附性能的影响,并分析了其吸附等温曲线。结果表明,单宁微球对Cr（Ⅵ）具有很好的吸附效果,吸附量可达到45.5 mg/g。单宁微球对Cr（Ⅵ）的去除率随吸附时间的延长而增大,5 h后基本达到平衡。温度对单宁微球吸附Cr（Ⅵ）的影响比较...     

猪骨基多孔炭对六价铬吸附性能的分析

以废弃的猪骨为原料制备的多孔炭作为吸附剂,分析了其对含Cr工业废水的净化作用,并对其吸附机理进行探讨。结果表明,吸附体系的pH、吸附时间、Cr(Ⅵ)初始浓度对多孔炭吸附Cr(Ⅵ)的能力影响较大,多孔炭材料的比表面积对其吸附水溶液中的Cr(Ⅵ)起决定性作用。该吸附过程符合二级动力学吸附模型,并且可用Langmuir吸附等温线来描述。所以猪骨基多孔炭有望成为含Cr(Ⅵ)废水的良好净化剂。     

纳米氧化镁对Cr(Ⅵ)、Cr(Ⅲ)和Cu(Ⅱ)的吸附特性

采用乳液法制备不同形貌的花状和片状MgO纳米粒子并研究其对Cr(Ⅵ)、Cr(Ⅲ)和Cu(Ⅱ)的吸附性能。运用静态吸附实验考察吸附时间和吸附剂MgO用量对Cr(Ⅵ)、Cr(Ⅲ)和Cu(Ⅱ)的去除率影响,探讨MgO纳米粒子的微观机构对其吸附性能的影响机制。结果表明,花状MgO和片状MgO对Cu(Ⅱ)、Cr(Ⅵ)和Cr(Ⅲ)离子表现出优异的吸附性能,对金属离子的去除效果是Cu(Ⅱ)Cr(Ⅵ)Cr(Ⅲ),5min基本达到吸附平衡;花状MgO对金属离子Cr(Ⅵ)和Cr(Ⅲ)的吸附性能明显优于片状MgO,这归因于比表面积大、多孔结构的花状MgO为金属离子提供更多的吸附活性位。与Temkin模型和Freundlich模型相比,Langmuir等温吸附模型更符合MgO样品在含Cu(Ⅱ)离子溶液体系中对Cr(Ⅵ)和Cr(Ⅲ)离子的吸附过程,这意味着Cr(Ⅵ)和Cr(Ⅲ)离子在MgO纳米粒子表面的吸附属于单分子层吸附。花状和片状MgO对金属铬离子的吸附行为符合伪一级动力学模型。     

纳米级二氧化锆的合成及其在六价铬污染处理中的应用

用溶胶－凝胶法合成了纳米级ZrO2,并采用透射电镜进行了表征。研究了纳米ZrO2对Cr(Ⅵ）的吸附。在pH4.0，吸附比为1：2900时，平均吸附率为85．48％，最大吸附量为301．4μg Cr（Ⅵ）/g。采用2mol/L NaOH可完全洗脱纳米ZrO2l所吸附的Cr(Ⅵ）。应用于环境水样中Cr(Ⅵ）的处理，水中残留Cr(Ⅵ)的浓度远小于Cr(Ⅵ)的排放标准。考察了回收纳米ZrO2对Cr(Ⅵ)的吸附效率，结果表明纳米级ZrO2可循环使用。     

贯通多孔聚合物微球的制备及其应用

采用高内水相双重乳液模板法制备贯通多孔聚合物微球,并将其应用于催化剂负载和Cu2+吸附.首先,通过增加水相,使单一小分子表面活性剂12-丙烯酰氧-9-油酸(AOA)稳定的反相高内相乳液(W/O HIPEs)发生相转变,一步制备出高内水相双重乳液;然后以此为模板,采用辐射法和引发剂引发聚合两种方式制备聚(苯乙烯-二甲基丙烯酸乙二醇酯)微球.通过扫描电镜观察发现,采用辐射法聚合能够得到贯通多孔的聚合物微球,而化学法聚合只能得到中空的封闭微球.将贯通多孔微球水解使其羧基化,用于铜离子的吸附.结果表明水解后多孔微球对Cu2+的吸附量随p H值的增加先增后减,在p H=5时达到最高值175 mg/g(2.75 mmol/g).此外,利用原位生成的方式,在贯通多孔微球上负载Pd纳米粒子,并将其用于催化肉桂醛加氢反应.结果表明水解多孔微球比未水解多孔微球具有更高的催化效率;热重分析和透射电子显微镜观察显示,水解多孔微球比未水解多孔微球能够负载更多的Pd纳米粒子,且纳米粒子分散更均匀.     

球型乙二醇单苯醚-甲醛负载三乙烯四胺螯合树脂的制备及其对Cu2+的吸附性能

以乙二醇单苯醚、甲醛为原料,采用分散聚合方法制备出乙二醇单苯醚-甲醛聚合物微球;经二甲亚砜氧化,制得醛基化改性微球(PB-CHO);微球(PB-CHO)与三乙烯四胺进行Schiff碱反应及加氢反应,制备出球型乙二醇单苯醚-甲醛负载三乙烯四胺螯合树脂(PB-TETA).对所制备的新型螯合树脂进行了红外光谱、扫描电镜等表征,并研究了PB-TETA对Cu2+的吸附性能.结果表明,在pH值为5时,PB-TETA对Cu2+的最大吸附量为0.16mmol/g;树脂对Cu2+的吸附受液膜扩散控制;吸附动力学符合拟一级动力学模型;等温吸附符合Langmuir吸附模型.     

生物吸附剂菹草干粉对Cr(Ⅵ)的吸附性能

开发了高效去除重金属Cr(Ⅵ)污染的生物吸附剂,菹草(Potamogeton crispus)干粉吸附剂,通过单因素分析考察了吸附时间、吸附剂颗粒大小、溶液初始pH值、吸附剂用量、Cr(Ⅵ)初始浓度以及离子强度等对重金属离子Cr(Ⅵ)的吸附性能。 结果表明,对吸附效果影响显著的因素有Cr(Ⅵ)初始浓度、吸附剂颗粒大小、溶液初始pH值和离子强度;其吸附行为符合准二级动力学方程,相关系数为0.9998;菹草对Cr(Ⅵ)的吸附等温线符合Langmuir方程。     

HAP/P(MMA-St)复合微球的制备及其吸附性能

以微孔纳米羟基磷灰石（HAP）为无机载体,甲基丙烯酸甲酯（MMA）和苯乙烯（St）为聚合单体,采用悬浮聚合法制备了HAP/P(MMA-St)复合微球。研究了影响球体粒度及其分布的主要因素和微球的吸附性能。结果表明,表面活性剂用量（质量分数,下同）为1‰、MMA用量为2%,HAP用量为30%,转速为300r/min时复合微球的合格球收率最高为86.4%。当微球中HAP的含量为36.07%时,HAP/P(MMA-St)微球对牛血清蛋白的最大吸附量Qe=18.70 mg/g,比未加HAP时,增加了4.65 mg/g。     

含氨基和环氧基双功能基的聚合物刷磁性微球的制备及对青霉素G酰化酶的固定化

在内部分散超顺磁性Fe3O4纳米粒子的二乙烯苯交联聚丙烯酸微球表面引入原子转移自由基聚合(ATRP)引发剂,引发聚合向微球表面分别引入P(GMMA-r-DMAEMA-r-GMA)、P(GMMA-r-DMAEMA)和P(GMMA-r-GMA)无规共聚物刷(GMMA为甲基丙烯酸甘油单酯,DMAEMA为甲基丙烯酸-N,N-二甲氨基乙酯,GMA为甲基丙烯酸缩水甘油酯),聚合物刷中GMMA链节的作用是使聚合物刷具有亲水性,DMAEMA引入氨基,GMA引入环氧基.研究了青霉素G酰化酶在这些载体上的固定化和其酶活性.结果表明,同时引入环氧基和氨基的P(GMMA-r-DMAEMA-r-GMA)刷磁性微球固定化青霉素G酰化酶的活性和活性收率都最高,其固定化动力学比只含环氧基P(GMMA-r-GMA)刷磁性微球的好.固定化酶比自由酶更耐热,固定化酶的最佳pH值比自由酶的略高,固定化酶重复使用10次后其活性保留70%.     

3,5-二硝基苯甲酸酯基改性的HEMA/NVP交联微球对肌酐的吸附特性与吸附机理

制备了平均粒径为180μm的甲基丙烯酸β-羟乙酯(HEMA)与N-乙烯基吡咯烷酮(NVP)交联共聚物微球(HEMA/NVP),使用3,5-二硝基苯甲酰氯(DNBC)对其进行了化学改性,制得了表面键合有大量3,5-二硝基苯甲酸酯基(DNBZ)的功能微球DNBZ-HEMA/NVP;采用红外光谱(FTIR)与化学分析法对其化学结构及组成进行了表征;重点研究了功能微球DNBZ-HEMA/NVP对肌酐的吸附特性与吸附机理.静态吸附实验表明,DNBZ-HEMA/NVP对肌酐具有强的吸附作用,交联微球HEMA/NVP经DNBC化学改性后,对肌酐的吸附容量提高了20倍;DNBZ-HEMA/NVP对肌酐的吸附性能受介质pH值及盐度的影响很大;当pH值较小或较大时,吸附容量都较低,pH=8.5时,吸附容量最大;介质的盐度越大,吸附容量越小.研究结果表明,DNBZ-HEMA/NVP对肌酐的吸附属化学吸附,而且是静电相互作用驱动下的化学吸附.     

Preparation of uniform-sized pH-sensitive quaternized chitosan microsphere by combining membrane emulsification technique and thermal-gelation method

In this study, uniform-sized pH-sensitive quaternized chitosan microsphere was prepared by combining Shirasu porous glass (SPG) membrane emulsification technique and a novel thermal-gelation method. In this preparation process, the mixture of quaternized chitosan solution and alpha-beta-glycerophosphate (alpha-beta-GP) was used as water phase and dispersed in oil phase to form uniform W/O emulsion by SPG membrane emulsification technique. The droplets solidified into microspheres at 37 degrees C by thermal-gelation method. The whole process was simple and mild. The influence of process conditions on the property of prepared microspheres was investigated and the optimized preparation condition was obtained. As a result, the coefficient of variation (C.V.) of obtained microspheres diameters was below 15%. The obtained microsphere had porous structure and showed apparent pH-sensitivity. It dissolved rapidly in acid solution (pH 5) and kept stable in neutral solution (pH 7.4). The pH-sensitivity of microspheres also affected its drug release behavior. Bovine serum albumin (BSA) as a model drug was encapsulated in microspheres, and it was released rapidly in acid solution and slowly in neutral medium. The novel quaternized chitosan microspheres with pH-sensitivity can be used as drug delivery system in the biomedical field, such as tumor-targeted drug carrier.     

Oil-Water Separation Performance of Electrospray Reduced Graphene Oxide Microspheres with a Local Radially Aligned and Porous Structure

Micro-size oil adsorbents are effective for the rapid remediation of special oil spills. Here, N-doped reduced graphene oxide(RGO) microspheres(ca. 150 μm in diameter) with a local radially aligned and porous structure are fabricated by combining electrospray-freeze-drying with thermal treatment for rapid separation of oil-water. Owing to its hydrophobic/oleophilic properties and oriented structure, the N-doped RGO microspheres achieve high capacities and fast adsorption rates for a variety of oils and organic solvents. Furthermore, excellent oil-water separation performance on floating oil/oil-water emulsions and stable cyclic adsorption capacities are obtained for the local radially aligned and porous microsphere. Therefore, N-doped RGO microspheres with the unique porous structure have the potential for the remediation of oily sewage and oil spills.     

A thermosensitive amphoteric microsphere and its potential application as a biological carrier

Thermosensitive poly(N-isopropylacrylamide) moieties were introduced onto amphoteric styrene/glycidyl methacrylate copolymer seed microspheres prepared by use of amphoteric initiators. The resulting microspheres exhibited thermosensitive and amphoteric behavior, so dual sensitivity to both pH and temperature was observed. The colloidal properties of the microspheres before and after seeded polymerization were characterized by varying the temperature and the pH. The results indicated that the specific surface structure emerged when the environmental conditions were changed. In addition, the reactive epoxy groups on the microsphere surface could be utilized to immobilize the protein molecules. The behavior of protein adsorption and immobilization onto the microspheres was examined in order to understand their potential applications in biological areas.     

Novel functionalized poly(glycidyl methacrylate‐co‐ethylene dimethacrylate) microspheres for the solid‐phase extraction of glycopeptides/glycoproteins

Novel 3‐aminophenylboronic acid functionalized poly(glycidyl methacrylate‐co‐ethylene dimethacrylate) microspheres were prepared for the solid‐phase extraction of glycopeptides/glycoproteins. The adsorption efficiency, maximum adsorption capacity, and specific recognition of the microspheres to glycoprotein were investigated. The results indicated excellent adsorption of glycoproteins by the microspheres, which are attributed to the well‐defined boronic acid brushes on the microsphere surfaces. Furthermore, a solid‐phase extraction microcolumn filled with the microspheres was used to efficiently enrich glycopeptides from enzymatic hydrolysates from human serum samples. The mass spectrometry results demonstrated that the method is suitable for the separation and enrichment of glycopeptides/glycoproteins from complex biological samples.     

Long-lived polymer radicals. IV. Reactions of poly(N-methylacrylamide) and poly(N-methylmethacrylamide) radicals with binary mixtures of vinyl monomers

N-methylacrylamide (NMAAm) and N-methylmethacrylamide (NMMAm) were polymerized to give polymer microspheres containing living propagating radicals. The microsphere polymer radicals were allowed to react with some binary mixtures of vinyl monomers including alternating copolymerization combinations. The reaction processes were investigated by ESR spectroscopy. In the poly(NMMAm) radical/methyl methacrylate (MMA)/styrene (St) system, the propagating radical from MMA was mainly observed at the higher MMA concentration, while polySt radical prevailed at the lower MMA concentration. In the poly(NMMAm) radical/α-methylstyrene (α-MeSt)/diethyl fumarate system, the α-MeSt radical was exclusively observed, while the maleic anhydride (MAn) radical was predominantly observed in the α-MeSt/MAn system. In the MAn/diphenylethylene system, the propagating radicals from both monomers were observed at comparable concentrations. The poly(NMAAm) microsphere radical behaved differently in the reaction with the MMA/St mixture. The poly(NMAAm) microsphere was found to incorporate preferentially St, leading to formation of the St radical. The St preference was enhanced in the St/cyclohexyl methacrylate (CHMA) system. These results were in agreement with those of block copolymerization via the reaction of poly(NMAAm) radical with the MMA/St or CHMA/St mixture, where the compositions of the resulting polymers were analyzed by pyrolysis gas chromatography.     

End‐linked amphiphilic polymer conetworks: Synthesis by sequential atom transfer radical polymerization and swelling characterization

Conetworks based on end‐linked homopolymers and amphiphilic gradient copolymers were synthesized by the atom transfer radical polymerization (ATRP) of 2‐(dimethylamino)ethyl methacrylate (DMAEMA, hydrophilic monomer), methyl methacrylate (MMA, hydrophobic monomer), and ethylene glycol dimethacrylate (EGDMA, hydrophobic cross‐linker). Sequential, rather than step‐wise polymerizations, were performed to enhance the livingness of the polymerization, particularly for the end‐linking step, and to ultimately obtain conetworks based on gradient rather than pure block copolymers. Amphiphilic conetworks based on end‐linked MMA‐DMAEMA‐MMA gradient copolymers of different compositions were successfully synthesized as confirmed by the narrow molecular weight distributions of the linear precursors, the rigidity of the amphiphilic conetwork products and the low sol‐fraction extracted from the conetworks. Similarly successful was the ATRP synthesis of an end‐linked conetwork based on a DMAEMA‐MMA statistical copolymer and of a randomly cross‐linked conetwork that resulted from the simultaneous terpolymerization of DMAEMA, MMA and EGDMA. An amphiphilic conetwork based on an end‐linked DMAEMA‐MMA‐DMAEMA gradient copolymer presented a less rigid, mucous‐like, texture. The degrees of swelling (DS) in tetrahydrofuran of all the conetworks were higher than those measured in pure water, whereas the aqueous DS values increased by lowering the pH and increasing the DMAEMA content of the conetworks. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1878–1886, 2010     

微孔羟基磷灰石/聚(甲基丙烯酸甲酯-苯乙烯)复合微球的制备及其吸附性能

以微孔纳米羟基磷灰石(HAP)为无机载体,甲基丙烯酸甲酯(MMA)和苯乙烯(St)为聚合单体,采用悬浮聚合法制备了HAP/P(MMA-St)复合微球。研究了影响球体粒度及其分布的主要因素和微球的吸附性能。结果表明,表面活性剂用量(质量分数,下同)为1‰,MMA用量为2%,HAP用量为30%,转速为300r/min时复合微球的合格球收率最高,为86.4%。当微球中HAP的质量分数为36.07%时,HAP/P(MMA-St)微球对牛血清蛋白的最大吸附量Qe=18.70mg/g,比未加HAP时,增加了4.65mg/g。