pH响应性表面对蛋白质吸附的调控

通过表面引发原子转移自由基聚合在固定了引发剂的硅表面接枝了聚甲基丙烯酸叔丁酯(PtBMA),而后通过水解得到聚甲基丙烯酸(PMAA)聚合物刷.通过X射线光电子能谱、椭圆偏振仪和水接触角测试证明了接枝改性的成功.研究发现PMAA改性表面的浸润性和对蛋白质的吸附行为都具有一定的pH响应性.在较低pH值时改性表面相对疏水,随...     

两种形貌的介孔SiO2对纤维素内切酶吸附性能的研究

以EDTA2-、SO42-作为反离子分别合成了具有管状和圆盘状结构的介孔SiO2,并测定了2种介孔SiO2焙烧至不同温度时的表面积、孔体积参数,及其等电点;通过752分光光度计在550nm处测定纤维素内切酶的吸光度,研究了2种形貌的介孔SiO2对纤维素内切酶的吸附性能,同时测定了固定酶的活性。结果表明,管状和圆盘状结构的介孔SiO2对纤维素内切酶的吸附等温线分别为Ⅱ和Ⅰ型;介孔SiO2焙烧至700℃时,两者皆为Ⅱ型;至850℃时,前者转化为Ⅰ型,而后者转化为Ⅴ型。吸附等温线类型与介孔SiO2的结构、等电点以及酶分子尺寸与介孔尺寸的相匹配有关。酶经过介孔SiO2吸附固定后,稳定性明显提高;其中,管状结构的介孔SiO2对酶具有最大的负载量,但固定酶的活性却较低。     

高分子材料与工程专业实践教学改革研究与探索

实践教学是培养大学生创新精神、创新能力和实践能力的最重要教学环节。本文阐述了高分子材料与工程专业实践教学的现状和存在的问题,总结了实验教学、生产实习、毕业设计这三大实践教学环节在人才培养过程中的重要作用。针对实践教学存在的问题和不足,我们着力构建新的培养模式和实践教学环境,增加研究性、探索性实践教学内容比例等,为培养具...     

Nanoporous carbons as promising novel methane adsorbents for natural gas technology

Nanoporous carbons were synthesized using furfuryl alcohol and sucrose as precursors and MCM-41 and mordenite as nanoporous templates.The produced nanoporous carbons were used as adsorbent for methane storage.The average pore diameter of the samples varied from 3.9 nm to 5.9 nm and the BET surface area varied from 320m2/g to 824m2/g.The volumetric adsorption experiments revealed that MCM-41 and sucrose had better performance compared with mordenite and furfuryl alcohol,correspondingly.Also,the effect of precursor to template ratio on the structure of nanoporous carbons and their adsorption capacities was investigated.The nanoporous carbon produced from MCM-41 mesoporous molecular sieve partially filled by sucrose shows the best methane adsorption capacity among the tested samples.     

A DFT theoretical study of CH_4 dissociation on gold-alloyed Ni(111)surface

A density-functional theory(DFT)method has been conducted to systematically investigate the adsorption of CHx(x=0～4)as well as the dissociation of CHx(x=1～4)on(111)facets of gold-alloyed Ni surface.The results have been compared with those obtained on pure Ni(111)surface.It shows that the adsorption energies of CHx(x=1～3)are lower,and the reaction barriers of CH4 dissociation are higher in the first and the fourth steps on gold-alloyed Ni(111)compared with those on pure Ni(111).In particular,the rate-determining step for CH4 dissociation is considered as the first step of dehydrogenation on gold-alloyed Ni(111),while it is the fourth step of dehydrogenation on pure Ni(111).Furthermore,the activation barrier in rate-determining step is higher by 0.41 eV on gold-alloyed Ni(111)than that on pure Ni(111).From above results,it can be concluded that carbon is not easy to form on gold-alloyed Ni(111)compared with that on pure Ni(111).     

Preparation of activated carbons and their adsorption properties for greenhouse gases: CH4 and CO2

Three kinds of activated carbons were prepared using coconut-shells as carbon precursors and characterized by XRD, FT-IR and texture property test. The results indicate that the prepared activated carbons were mainly amorphous and only a few impurity groups were adsorbed on their surfaces. The texture property test reveals that the activated carbons displayed different texture properties, especially the micropore size distribution. The adsorption capacities of the activated carbons were investigated by adsorbing CH4, CO2, N2 and O2 at 25 ?C in the pressure range of 0-200 kPa. The results reveal that all the activated carbons had high CO2 adsorption capacity, one of which had the highest CO2 adsorption value of 2.55 mmol/g at 200 kPa. And the highest adsorption capacity for CH4 of the activated carbons can reach 1.93 mmol/g at 200 kPa. In the pressure range of 0-200 kPa, the adsorption capacities for N2 and O2 were increased linearly with the change of pressure and K-AC is an excellent adsorbent towards the adsorption separation of greenhouse gases.     

Study of CO adsorption on perfect and defective pyrite(100)surfaces by density functional theory

First-principles calculations based on density functional theory (DFT) and the generalized gradient approximation (GGA) have been used to study the adsorption of CO molecule on the perfect and defective FeS 2 (100) surfaces. The defective Fe 2 S(100) surfaces are caused by sulfur deficiencies. Slab geometry and periodic boundary conditions are employed with partial relaxations of atom positions in calculations. Two molecular orientations, Cand O-down, at various distinct sites have been considered. Total energy calculations indicated that no matter on perfect or deficient surfaces, the Fe position is relatively more favored than the S site with the predicted binding energies of 120.8 kJ/mol and 140.8 kJ/mol, respectively. Moreover, CO was found to be bound to Fe atom in vertical configuration. The analysis of density of states and vibrational frequencies before and after adsorption showed clear changes of the C–O bond.     

壳聚糖对酸性艳橙GS的吸附平衡与动力学研究

研究了壳聚糖(CS)对水溶液中的酸性艳橙GS(ABO)染料的吸附性能,考察了温度、pH值、壳聚糖分子量对吸附性能的影响.不同温度下的动力学数据分别采用拟一级、拟二级、内扩散方程进行关联;不同温度下壳聚糖对酸性艳橙GS的吸附平衡数据分别用1angmuir、Freundlich、Tempkin模型拟合.结果表明:该吸附过程...     

左氧氟沙星印迹聚合物微球及其特异吸附研究

以甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,采用沉淀聚合法制备了左氧氟沙星印迹聚合物(MIP)微球,用SEM和IR分别对微球形貌和结构进行表征,用静态吸附法和Scatchard分析考察了聚合物微球对模板及其结构类似物的吸附行为和选择性识别能力.结果表明,MIP对模板分子的吸附平衡速度快,40min即可达到吸附...     

介孔L材料CMK-3对甲基紫的吸附性能

合成了高度有序的具有二维六方(P6mm)结构的介孔碳材料CMK-3;利用X射线衍射分析了CMK-3的晶体结构,利用氮气吸脱附(BET)试验测定了孔体积;测定了CMK-3对水溶液中甲基紫的吸附行为,考察了不同pH、温度及浓度下水溶液中甲基紫的静态吸附行为,并分析了酸性、中性、碱性条件下吸附剂对甲基紫和罗丹明B混合溶液的竞...