Immobilized fenton‐like ionic liquid: Catalytic performance for oxidative desulfurization

MCM‐41‐supported Fenton‐like ionic liquid catalysts were synthesized by the grafting method and applied in the removal of sulfur compounds in model oil. The structure and property of the catalysts were characterized by Fourier transform infrared spectra, X‐ray diffraction, diffuse reflectance spectra, transmission electron microscopy, thermogravimetric and differential scanning calorimetry, and N₂ adsorption‐desorption. Results suggested that Fenton‐like ionic liquid was supported on mesoporous material MCM‐41. Different desulfurization systems were studied. The results indicated that at room‐temperature (30°C) for 1 h, MCM‐41‐supported Fenton‐like ionic liquid in extraction combined with catalytic oxidative desulfurization (ECODS) system showed a high catalytic activity with H₂O₂ as the oxidant, and [Omim]BF₄ as the extractant. Different factors, such as temperature, the amount of H₂O₂, solvent, and different sulfur‐containing compounds for sulfur removal were investigated. Through the gas chromatography‐mass spectrometer (GC‐MS) analysis, dibenzothoiphene sulfone was proved to be the only product of dibenzothiophene oxidizing reaction. Furthermore, the process of ECODS was confirmed by GC‐MS results. © 2013 American Institute of Chemical Engineers AIChE J, 59: 4696–4704, 2013     

BiOCl光催化剂的改性和固定化研究进展

氯氧化铋(BiOCl)是一种具有良好光催化活性的的新型半导体光催化剂,其独特的层状结构和电子性质决定了它在化工、环保、能源等领域有着巨大的应用前景。本文针对BiOCl光催化剂在应用中存在的问题,对BiOCl光催化剂的掺杂改性和固定化研究进展进行了综述,并对BiOCl光催化剂的研究方向及存在问题进行了展望。     

甲基三氧化铼负载化研究进展

综述了近年来对金属有机催化剂甲基三氧化铼负载化方法的研究进展。介绍了甲基三氧化铼通过物理吸附或化学吸附负载在不同载体材料上的方法及负载后作为非均相催化剂在烯烃环氧化、硅烷氧化、烯烃复分解和Bacyer-Villiger等多种反应中的应用,同时指出与单纯使用甲基三氧化铼进行的均相催化反应过程相比,通过物理吸附法负载后的催化剂在循环催化反应中,催化剂不可避免流失问题,以及通过化学吸附法负载后导致催化剂的失活问题,并对今后的发展趋势进行展望。     

磁性壳聚糖微球的合成及其在固定化血管紧张素转化酶的应用

以化学共沉淀法合成Fe3O4纳米粒子为磁核,采用乳化交联法制备磁性壳聚糖微球,并对其形貌、结构和磁饱和强度等性质进行了表征。以磁性壳聚糖微球作为载体,固定化猪肺粗提物中的血管紧张素转化酶,并对固定化条件进行研究。结果表明,固定化血管紧张素转化酶的最佳条件为：pH值为8.3,最佳温度为50 ℃,最佳时间为1.5 h,最佳酶溶液蛋白浓度为6 mg/mL,此时固定化酶活力最高为0.048 U/g微球。与游离酶相比,固定化酶的pH值稳定性和热稳定性均得到提高。固定化酶重复使用10次,仍然保持40%以上相对活力,说明磁性壳聚糖微球是固定化血管紧张素转化酶的良好载体。     

离子液体绿色脱硫机理及应用进展

从离子液体脱硫的影响因素、脱硫机理、脱硫方法及新型离子液体--负载化离子液体等几个方面综述了离子液体在油品脱硫中的应用。离子液体独特的化学结构和优良的物化性质,使其应用于油品脱硫时有其它有机溶剂无可比拟的优势,取得了很好的脱硫效果,尤其是与其它工艺（如氧化法）相结合时,脱硫效果更佳。但是离子液体存在价格昂贵、用于油品脱硫时分离不完全等缺点,工业应用有困难,负载化离子液体在一定程度上克服了这些问题,应用于油品脱硫发展前景广阔。     

DNA在GO-PANI复合材料表面上的固定/杂交

采用氧化还原法制备氧化石墨烯(GO),通过原位插层聚合法制备出GO与导电聚苯胺(PANI)复合层状纳米材料。采用旋涂法将GO–PANI复合材料旋涂在自组装有十八烷三甲氧基硅烷的硅片上,对核糖核酸(DNA)在复合材料表面上的固定进行电化学性能测试。结果表明,DNA能够很好地固定在GO–PANI复合材料表面上,对将来开发出易于制备的电化学性能优良的DNA芯片提供了实验基础。     

磁性壳聚糖复合微粒固定化SOD的研究

制备了磁性壳聚糖复合微粒(Fe3O4/CS),并以Fe3O4/CS为载体固定了超氧化物歧化酶(Superoxide Dismutase,SOD)。研究了温度、pH、储存时间、操作次数等对固定化SOD和游离SOD活性的影响。研究结果表明,固定化SOD的热稳定性、pH稳定性、储存稳定性等性能明显优于游离SOD,固定化SOD的操作稳定性良好。研究了固定化SOD和游离SOD的半衰期t1/2和动力学性质。固定化SOD的半衰期t1/2,1=35.7 d,游离SOD的半衰期t1/2,2=8.8 d;固定化SOD的米氏常数Km,1=0.04 mmol/L,最大反应速率Vm,1=40.19 mmol/min,游离SOD的米氏常数Km,2=0.19 mmol/L,最大反应速率Vm,2=85.76 mmol/min。     

PVA固定高效苯酚降解菌的性能

生物降解含酚废水是一种既经济又有效的方法,固定微生物可以快速降解除酚。通过对高效苯酚降解细菌（XA05）的几种不同固定方法进行比较,最后确定采用PVA冰冻解冻固定法。研究了聚乙烯醇（PVA）生物膜浓度、包埋细菌浓度对降解苯酚性能的影响,最终选取PVA浓度为10%g/g,包埋细菌浓度为4% g/g的生物膜。并将所制PVA生物膜活化后与游离细菌对苯酚的降解能力进行比较,结果表明,在不同pH值、温度下生物膜对苯酚的降解速率优于游离细菌,PVA冰冻解冻法包埋XA05对含酚废水的生物处理是一种有效的方法。     

Immobilization of biologically active species on PA‐6 foils treated by a dielectric barrier discharge

In the field of biomaterials and biomedical devices, surface activation has been focused on creating functional groups capable of preferential adsorption of biologically active species (proteins, enzymes, cells, drugs, etc.). In this way an interface can be created between the synthetic material and the biological medium, with the aim of increasing the compatibility of the implant with the human organism. In our experiments a dielectric barrier discharge (DBD), in helium at atmospheric pressure, was used as the source of energy capable of creating active centers that render the functionalized surface favorable to immobilization of biological molecules. Retention of immunoglobulin (IgG) and heparin biomolecules on polyamide‐6 (PA‐6) surfaces after treatment by the DBD was analyzed by atomic force microscopy, adhesion evaluation, and measurement of the contact angle titration in order to assess this incorporation on the treated surfaces. The marked adsorption of the biomolecules on the active sites created by DBD on the exposed surfaces also was related to a complex set of processes, such as enhanced roughness, increased surface wettability, and modified distribution of cationic and anionic groups on the treated surfaces. All these factors could promote interfacial interactions between the specific groups of the biomolecules existing in the biological medium and the type of cationic and/or anionic groups present on the surface. The efficiency of the DBD treatment showed that the DBD technique is useful for preactivation of the polymer surface for immobilization of other biologically active species (such as drugs and enzymes). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1985–1990, 2003     

Electrical Current Signatures of DNA Base Modifications in Single Molecules Immobilized in the α-Hemolysin Ion Channel

Nanopore technology holds high potential for next-generation DNA sequencing. This method operates by drawing an individual single-stranded DNA molecule through a nanoscale pore, while monitoring the current deflections that occur as the DNA passes through. Individual current levels for the four DNA nucleotides have been established by immobilization of an end biotinylated strand in the pore, in which the nucleotide of interest is suspended at the most sensitive region of the ion channel. Due to the inherent reactivity of DNA bases, many modified nucleotides in the genome exist as a result of oxidative and UV insults, among others. Herein, the current levels for common DNA damage lesions 8-oxo-7,8-dihydroguanine, spiroiminodihydantoin, guanidinohydantoin, uridine, abasic sites, thymine dimers, thymine glycol, and 5-iodocytosine were assessed through immobilization experiments. In some cases, the current difference between the damaged and canonical nucleotides was not well resolved; therefore, we took advantage of the chemical reactivity of the new functional groups present to make amine adducts that shifted the current levels outside the range of the native nucleotides. Among the adducts studied, only the 2-aminomethyl-18-crown-6 adduct was able to give a large current shift in the immobilization experiment, as well as being observed in a translocation experiment. The results show potential in providing current-level modulators for identification of some types of DNA damage. In principle, any DNA base modification that can be converted chemically or enzymatically into an abasic site could be identified in this way.