Structure controlling and adsorption application of polyethersulfone porous microspheres prepared via electrospraying

The focus of this work is to control the structure of electrosprayed polymer microspheres and then study the effect of different structures on the microspheres＇ adsorption properties. Scanning electron microscopy （SEM） coupled with image analysis software was employed to evaluate the size distributions and the structure of microspheres. According to the observation and analysis results, two types of polyethersulfone （PES） porous microspheres （perfect sphere-shaped and collapsed） were prepared via electrospraying technology by adjusting the solvent and polymer molecular weight. The porous PES microspheres can remove bisphenol A （BPA） from its aqueous solution effectively. Compared with collapsed microspheres, the rough microspheres had much higher specific surface area and better mobility in the BPA aqueous solution, so it showed a better adsorption capacity than that of collapsed microspheres. The solvent evaporation rate and the occurrence rate of phase separation significantly affect the structure and morphology of microspheres.     

Magnetically separated and N,S co-doped mesoporous carbon microspheres for the removal of mercury ions

Magnetically separated and N, S co-doped mesoporous carbon microspheres (N/S-MCMs/Fe₃O₄) are fabricated by encapsulating SiO₂ nanoparticles within N, S-containing polymer microspheres which were prepared using resorcinol/formaldehyde as the carbon source and cysteine as the nitrogen and sulfur co-precursors, followed by the carbonization process, silica template removal, and the introduction of Fe₃O₄ into the carbon mesopores. N/S-MCMs/Fe₃O₄ exhibits an enhanced Hg²⁺ adsorption capacity of 74.5 mg/g, and the adsorbent can be conveniently and rapidly separated from wastewater using an externalmagnetic field. This study opens up new opportunities to synthesize welldeveloped, carbon-based materials as an adsorbent for potential applications in the removal of mercury ions from wastewater.     

QDs-labeled microspheres for the adsorption of rabbit immunoglobulin G and fluoroimmunoassay

This paper presents a study on the adsorption of rabbit immunoglobulin G onto CdTe quantum dots (QDs)/polystyrene microspheres. The adsorption appears to be sensitive to pH conditions and ionic strength. Maximum adsorption for protein was obtained near the isoelectric point. Adsorption isotherm analysis demonstrated that the electrostatic interaction plays an important role in the adsorption of protein. The thickness of adsorbed layer calculated from the maximal adsorption amounts (q(m)) is 6.5 nm, which indicates that the rabbit IgG molecules exist between the side-on and end-on mode in the monolayer. The bio-functional rabbit IgG/fluorescent microspheres were further used for the detection of antibody in fluoroimmunoassays. This approach allowed detection of goat anti-rabbit IgG in the range of 1-100 ng/mL.     

Preparation of chitosan/N-doped graphene natively grown on hierarchical porous carbon nanocomposite as a sensor platform for determination of tartrazine

In this work,the chitosan and N-doped graphene natively grown on hierarchical porous carbon(N-PC-G/CS) nanocomposite was obtained by ultrasonic method,as a novel sensor platform for determination of tartrazine(TT).The nanocomposite as prepared had well dispersivity in water and excellent conductivity.The N-PC-G/CS nanocomposite was characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM),nitrogen adsorption-desorption,fourier transform infrared(FTIR) and electrochemical impedance spectroscopy(EIS).The application of N-PC-G/CS for determination of tartrazine(TT) was investigated by chronocoulometry(CC),cyclic voltammetry(CV) and differential pulse voltammetry(DPV).Under optimized conditions,the sensor displayed a sensitive response to TT within a wide concentration range of 0.05-15.0 μmol/L,the detection limits is 0.036 μmol/L(S/N = 3).Furthermore,this nanocomposite could be efficiently applied for determination of TT in soft drink samples.     

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,成功制备了单分散甲基丙烯酸甲酯/甲基丙烯酸二甲基氨基乙酯（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。研究了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：pH对微球吸附Cr(Ⅵ)的量有较大影响,当pH=3时,微球对Cr(Ⅵ)吸附率达到52.9%;循环4次后微球吸附率基本不降低,循环性能好;微球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。     

Preparation of PLGA microspheres with different porous morphologies

Poly(D,L-lactide-co-glycolide)(PLGA) microspheres were prepared by emulsion solvent evaporation method. The influences of inner aqueous phase, organic solvent, PLGA concentration on the morphology of microspheres were studied. The results showed that addition of porogen or surfactants to the inner aqueous phase, types of organic solvents and polymer concentration affected greatly the microsphere morphology. When dichloromethane was adopted as organic solvent, microspheres with porous structure were produced. When ethyl acetate served as organic solvent, two different morphologies were obtained. One was hollow microspheres with thin porous shell under a lower PLGA concentration, another was erythrocyte-like microspheres under a higher PLGA concentration. Three types of microspheres including porous, hollow core with thin porous shell(denoted by hollow in brief) and solid structures were finally selected for in vitro drug release tests. Bovine serum albumin(BSA) was chosen as model drug and encapsulated within the microspheres. The BSA encapsulation efficiency of porous, hollow and solid microspheres was respectively 90.4%, 79.8% and 0. And the ultimate accumulative release was respectively 74.5%, 58.9% and 0. The release rate of porous microspheres was much slower than that of hollow microspheres. The experiment results indicated that microspheres with different porous structures showed great potentials in controlling drug release behavior.     

光致变色多孔聚苯乙烯功能微球的制备和性能

以甲苯/庚烷为致孔剂,利用分散聚合技术制备了多孔交联聚苯乙烯微球.研究了聚合单体、引发剂、稳定剂、交联剂等对微球平均粒径的影响,并初步评价了其在常温常压下吸附光致变色材料后的光致变色性能.结果表明,在最佳条件下制得的多孔聚合物微球平均粒径为1 μm;吸附光致变色材料后,其在紫外或日光照射下具有快速可逆的光致变色功能.利...     

Surface treatment and porosity control of porous silica microspheres

Summary Porous silica microspheres (PSM) have been treated with ammonium bifluoride to adjust porosity, pore size, remove surface impurities, and minimize surface acidity. The porosities of four silicas having mean pore diameters ranging from 150 to 750 ? have been altered from initial values to the point at which the mechanical strength is insufficient to allow packed columns with acceptable performance. It is shown that a linear relationship exists between a change in porosity and the relative amount of ammonium bifluoride used to treat the silica. This reagent removes silica homogeneously from all pores in a given microsphere in a controllable and predictable manner. This treatment increases the peak capacity and improves chromatographic performance. The surfaces of treated silicas were probed with thiamine in the ion-exchange chromatographic mode. The slopes and intercepts of plots in which retention is plotted against the reciprocal of buffer concentration were both significantly reduced indicating that surface acidity is minimized by this treatment.     

Preparation of poly(methyl methacrylate) films containing silica particle array structure from colloidal crystals

The incorporation of monodisperse, polymer-modified silica into poly(methyl metharylate) to prepare polymer films containing particle array structure was investigated. The preparation was carried out by a two-step radical polymerization for gelation and solidification. The colloidal crystallization of poly(methyl metharylate)-modified silica, in 78 nm size, in acetonitrile and successive copolymerization of methyl methacrylate and 1,2-dimethacryloylethane by UV light irradiation gave the polymer gel containing the colloidal crystal structure. The exchange of acetonitrile in the gel with methyl methacrylate and further photo-radical polymerization gave the durable polymer film composed of silica particle array.     

Implanting Ni into N-doped puffed carbon: A new advanced electrocatalyst for oxygen evolution reaction

Tailored design and synthesis of high-quality electrocatalysts is vital for the advancement of oxygen evolution reaction (OER). Herein, we report a powerful puffing method to fabricate hierarchical porous N-doped carbon with numerous embedded Ni nanoparticles. Interestingly, during the puffing and annealing process, rice precursor with N and Ni sources can be in-situ converted into Ni-embedded N-doped porous carbon (N-PC/Ni) composite. The obtained N-PC/Ni composite possesses a cross-linked porous architecture containing conductive carbon backbone and active Ni nanoparticles electrocatalysts for OER. The pore formation in N-PC/Ni composite is also proposed because of carbothermic reduction. The N-PC/Ni composite is fully studied as electrocatalysts for OER. Due to increased active surface area, enhanced electronic conductivity and reactivity, the designed N-PC/Ni composite exhibits superior OER performance with a low Tafel slope (∼88 mV/dec) and a low overpotential as well as excellent long-term stability in alkaline solution. Our proposed rational design strategy may provide a new way to construct other advanced metal/heteroatom-doped composites for widespread application in electrocatalysis.     

Preparation of porous biodegradable microspheres with direct melting dispersion method

Porous biodegradable microspheres can be prepared by using the direct melting dispersion method without any noxious organic solvents, in which the biodegradable polymer is directly melted and stirred to form the liquid–liquid dispersion followed by cooling in the continuous phase, such as ethylene glycol with the higher melting temperature than polymer. In the experiment, polyhydroxybutyrate (PHB) was adopted as the biodegradable polymer. As particulate porogen, magnetite powder was pre‐mixed into the melted polymer and removed by hydrochloric acid aqueous solution after preparation of the microspheres to make them porous. It was found that the inner surface area was significantly increased by removing magnetite powder. Copyright © 2007 John Wiley & Sons, Ltd.     

Preparation of novel porous carbon spheres from corn starch

Irregular porous carbon spheres were successfully prepared from Na₂SnO₃ coated corn porous starch by carbonization. The product was characterized with X-ray diffraction and scanning electron microscope (SEM). It is verified that the irregular porous carbon spheres are composed of disordered carbon, and the skeleton and pores of the corn porous starch was well preserved after carbonization. The pore size of the irregular porous carbon spheres is almost the same, which is similar to that of the porous starch. And the pore size decreases from about 0.91 μm to 0.53 μm measured from the SEM pictures. The texture of the irregular porous carbon spheres is mainly determined by that of porous starch.     

Facile preparation of hierarchically porous carbon using diatomite as both template and catalyst and methylene blue adsorption of carbon products

Hierarchically porous carbons were prepared using a facile preparation method in which diatomite was utilized as both template and catalyst. The porous structures of the carbon products and their formation mechanisms were investigated. The macroporosity and microporosity of the diatomite-templated carbons were derived from replication of diatom shell and structure-reconfiguration of the carbon film, respectively. The macroporosity of carbons was strongly dependent on the original morphology of the diatomite template. The macroporous structure composed of carbon plates connected by the pillar- and tube-like macropores resulted from the replication of the central and edge pores of the diatom shells with disk-shaped morphology, respectively. And another macroporous carbon tubes were also replicated from canoe-shaped diatom shells. The acidity of diatomite dramatically affected the porosity of the carbons, more acid sites of diatomite template resulted in higher surface area and pore volume of the carbon products. The diatomite-templated carbons exhibited higher adsorption capacity for methylene blue than the commercial activated carbon (CAC), although the specific surface area was much smaller than that of CAC, due to the hierarchical porosity of diatomite-templated carbons. And the carbons were readily reclaimed and regenerated.     

Oxygen vacancy promoting adsorption property of BiOI microspheres modified with SDS

8% SDS-BiOI microspheres possessed the homogeneous morphology, larger specific surface area and more oxygen vacancies compared with the pure BiOI, and the 8% SDS-BiOI showed the higher adsorption performance of different dyes relative to the pure BiOI sample.     

Preparation of core-shell microporous organic polymer-coated silica microspheres for chromatographic separation and N-glycopeptides enrichment

Through a “one-pot” strategy, a layer of microporous organic polymer was coated onto the surface of monodisperse amino-functionalized silica microsphere via amino-aldehyde condensation reaction with core-shell structure. The change in chemical structure of material before and after modification was determined by Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. Due to existence of a large number of amino and aldehyde groups in microporous organic polymer shell, the water contact angle decreased from 56.8° (silica microspheres) to 34.7° (microporous organic polymer-coated silica microspheres). Based on these properties, microporous organic polymer-coated silica microspheres were employed as the stationary phase for capillary liquid chromatography and successfully offered baseline separation of polar small molecules. Additionally, the material could also be served as the sorbent of hydrophilic interaction chromatography to enrich glycopeptides from human serum digest. A total of 470 unique N-glycopeptides and 342 N-glycosylation sites mapped to 112 N-glycosylated proteins were unambiguously identified from 2 μL of human serum, exhibiting a promising application prospect of microporous organic polymer-coated silica microspheres in the pretreatment of proteomics samples.     

Preparation of porous carbon directly from hydrothermal carbonization of fructose and phloroglucinol for adsorption of tetracycline

Hydrothermal carbonization of biomass is a promising method to prepare carbonaceous materials. Generally, post physical or chemical activation is necessary to increase surface area and porosity of the carbon. Herein, porous carbonaceous material (FPC) with large surface area (481.7 m²/g) and pore volume (0.73 cm³/g) was prepared directly from hydrothermal carbonization of fructose and phloroglucinol in hydroalcoholic mixture. Structure characteristics of the FPC and its adsorption capacity for a representative antibiotic tetracycline in aqueous solution were investigated. This work provides a green and efficient method to fabricate porous carbonaceous adsorbent that has great potential applications in chemical and environmental fields.     

Preparation of phosphorylated chitosan‐coated carbon microspheres as flame retardant and its application in unsaturated polyester resin

In this work, phosphorylated chitosan‐coated carbon microspheres (PCH@CMS) was successfully synthesized. Obtained PCH@CMS used as flame retardant was added into unsaturated polyester resin (UPR). Fourier infrared spectroscopy (FTIR) and X‐ray electron spectroscopy (XPS) results indicated that C═O, P─O, and P═O appeared on the surface of PCH@CMS. Compared with UPR, the residues of UPR/PCH@CMS‐10 at 800°C under nitrogen and air atmospheres increased by 9.0 and 3.9 wt%, respectively, and the peak heat release rate (pHRR) and the peak smoke release rate (pSPR) of UPR/PCH@CMS‐3 decreased by 18.9% and 23.5%, respectively. Limiting oxygen index (LOI), thermogravimetric analyzer (TG), and cone calorimeter test (CCT) results showed that the addition of PCH@CMS could enhance the flame retardancy and smoke suppression of the UPR composites. Moreover, the residues after CCT were characterized by scanning electron microscopy (SEM), XPS, and laser Raman spectroscopy (LRS). Based on the above results, the flame retardant mechanism of PCH@CMS was proposed. The carbon layer produced by the UPR/PCH@CMS composites was tortuous and could suppress the heat and pyrolysis product exchange with UPR matrix.     

基于静电喷射法活性多孔磁性炭球的制备及其对亚甲基蓝的吸附

在利用静电喷射一步法获得壳聚糖(CS)磁性微球(Fe₃O₄/CS)的基础上,对Fe₃O₄/CS进行高温炭化和碱活化处理获得活性磁性多孔炭球(A-Fe₃O₄/C),并对A-Fe₃O₄/C吸附水中亚甲基蓝(MB)分子的性能进行了研究。在利用扫描电子显微镜、红外吸收光谱仪、比表面分析仪对制备微球的形貌和结构进行分析的基础上,深入研究溶液pH、吸附时间、温度以及活化剂种类等因素对A-Fe₃O₄/C吸附性能的影响。研究结果表明,A-Fe₃O₄/C对MB的吸附量随着pH值的增加而增大,且经KOH活化后的A-Fe₃O₄/C对MB表现出较优的吸附性能。A-Fe₃O₄/C对MB的吸附过程符合伪二级动力学方程和Langmuir等温线模型,理论最大吸附容量可达300.6 mg·g^-1。此外,A-Fe₃O₄/C表现出良好的重复利用性能,6次循环后对MB的去除率没有明显下降。     

基于静电喷射法活性多孔磁性炭球的制备及其对亚甲基蓝的吸附

在利用静电喷射一步法获得壳聚糖(CS)磁性微球(Fe₃O4/CS)的基础上,对Fe₃O4/CS进行高温炭化和碱活化处理获得活性磁性多孔炭球(A-Fe₃O4/C),并对A-Fe₃O4/C吸附水中亚甲基蓝(MB)分子的性能进行了研究。在利用扫描电子显微镜、红外吸收光谱仪、比表面分析仪对制备微球的形貌和结构进行分析的基础上,深入研究溶液pH、吸附时间、温度以及活化剂种类等因素对A-Fe₃O4/C吸附性能的影响。研究结果表明,A-Fe₃O4/C对MB的吸附量随着pH值的增加而增大,且经KOH活化后的A-Fe₃O4/C对MB表现出较优的吸附性能。A-Fe₃O4/C对MB的吸附过程符合伪二级动力学方程和Langmuir等温线模型,理论最大吸附容量可达300.6 mg·g^-1。此外,A-Fe₃O4/C表现出良好的重复利用性能,6次循环后对MB的去除率没有明显下降。