Adsorption separation performance of H_2/CH_4 on ETS-4 by concentration pulse chromatography

To exploit an effective adsorbent to separate hydrogen and methane, microporous titanium silicate molecular sieve NaETS-4 was synthesized and modified by strontium. The adsorption characteristics and diffusion behaviors of the prepared titanosilicate molecular sieve were studied by concentration pulse chromatography. And the effects of ion-exchange and dehydration temperature on adsorbent structure and gas diffusion were also discussed. The results showed that the thermal stability and Henry＇s Law constants were enhanced and micropore diffusivity decreased after exchanging Na＋ with Sr2＋. With the increase of dehydration temperature, Henry＇s Law constant and micropore diffusivity of CI-I4 decreased in both NaETS-4 and SrETS-4. While for 1-12 in SrETS-4, the increase of Henry＇s Law constant and the decrease of diffusion rate can be attributed to the shrinks of pore diameter resulting from the relocation of Sr2＋. Correspondingly, the kinetic selectivity of H2/CH4 reached 8.91 indicating its potentiality in separating H2 and CH4.

THE DETERMINATION OF ADSORPTION ISOTHERMS AND SOLID DEFFUSION COEFFICIENTS OF MANNITOL AND SORBITOL BY LIQUIDCHROMATOGRAPHY TECHNIQUE

The Parameter identification model is proposed for determining the linear adsorptionisotherms and the solid diffusion coefficients by using adsorption chromatography. Axialdispersion coefficients is firstly determined by pulse-respond experiment technique with aninert substance as tracer then the elution curves of chromatography separating the isomermannitol and sorbitol are determined by the chromatographic measuring technique, andfinally the adsorption isotherms and the solid diffusion coefficients of mannitol andsorbitol on Ca2+ resins are estimated by using this model. The results show that the axialdispersion coefficients increase with fluid velocity increasing, the adsorption equilibriumconstants decrease with temperature rising;and the solid diffusion coefficients increasewith temperature rising. The theoretical elution curves are good agreement with theexperimental elution curves of the liquid adsorption chromatography separating themannitol and the sorbitol. The model provides a simple and reliable procedure to estimatethe kinetic and thermodynamic parameters of the adsorption.

ISOLATION AND PURIFICATION OF ALKALOIDS FROM PLUMULA NELUMBINIS BY DOUBLE-COLUMN ADSORPTION CHROMOTOGRAPHY

The performance of adsorption and separation for liensinine, isoliensinine and neferine was studied by double-column adsorption chromatography using macroporous adsorption and cation exchange resins. The alkaloid extract with 49.2% total contents by mass representing 10.6% liensinine, 10.6% isoliensinine and 28.0% neferine respectively was prepared by D72 cation exchange resins, in which most of the impurities were water-soluble alkaloids. Furthermore,the alkaloid extract with 82.6% total contents by mass containing 33.1%, 15.0% and 34.5% of the three adsorbates respectively was prepared by double-column adsorption chromatography using AKS-W macroporous adsorption and D72 cation exchange resins. As a result, the content of single and total alkaloids has been greatly increased by the double-column adsorption chromatography.

Adsorption behaviors of avian immunoglobulins and purification of immunoglobulin Y from chicken serum with mixed-mode resins

The importance of immunoglobulin Y(IgY) as a specific antibody equivalent to mammalian immunoglobulin G(IgG) is well recognized. However, production of highly purified IgY is still difficult due to the lack of specific purification methods. In this study, adsorption behaviors of Ig Y on four mixed-mode resins with functional ligands of 4-mercatoethyl-pyridine(MEP), 2-mercapto-1-methyli-midazole(MMI), 5-aminobenzi-midazole(ABI) and tryptophan-5-aminobenzi-midazole(W-ABI) were evaluated. The results showed that high adsorption ratio were found at p H 6.0–7.0 with little adsorption under acidic conditions. The resin with ABI ligand was then used to separate IgY from immunized chicken serum. An efficient process with Ig Y purity of 95% and recovery of 90% was developed after optimization of loading and elution p H and injection volume. The biological activity of the purified Ig Y was fully maintained. These results indicated that mixed-mode chromatography with specially-designed ligands has great potential for the separation of Ig Y from crude feedstock.

Adsorbents for Expanded Bed Adsorption： Preparation and Functionalization

Expanded bed adsorption(EBA),a promising and practical separation technique,has been widely studied in the past two decades.The development of adsorbents for EBA process is a challenging course,with the special design and preparation according to the target molecules and specific expanded bed systems.Many types of supporting matrices for expanded bed adsorbents have been developed,and their preparation methods are being consummated gradually.These matrices are activated and then coupled with ligands to form functionalized adsorbents,including ion-exchange adsorbents,affinity adsorbents,mixed mode adsorbents,hydrophobic charge induction chromatography adsorbents and others.In this review,the preparation of the matrices for EBA process is summa-rized,and the coupling of ligands to the matrices to prepare functionalized adsorbents is discussed as well.

Protein adsorption onto diethylaminoethyl dextran modified anion exchanger:Effect of ionic strength and column behavior

Our previous studies on bovine serum albumin(BSA) adsorption to diethylaminoethyl dextran(DEAE dextran,DexD, grafting-ligand) and DEAE(D, surface-ligand) modified Sepharose FF resins found that all the grafted resins(FF-DexD and FF-D-DexD) exhibited extremely fast uptake rate(effective diffusivity, D_e, D_e/D_O> 1.4),which was six times greater than the ungrafted resins(D_e/D_O < 0.3). In this work, the influence of ionic strength(IS) on 6 typical DEAE dextran-grafted resins was investigated. Bath adsorption equilibria and kinetics, breakthrough, and linear gradient elution experiments were conducted. Commercial DEAE Sepharose FF was used for comparison. It is found that protein adsorption capacities on DEAE dextran-FF resins and the commercial resin decreased with increasing IS, but DEAE dextran-FF resins exhibited much higher capacity sensitivity to salt concentration. Besides, steeper decrease of adsorption capacities could be obtained at higher graftingligand or surface-ligand density. It is worth noting that the facilitating role of surface-ligand to the "chain delivery" effect was weakened after adding salt, leading to the less improvement in uptake rate by increasing surface-ligand density at higher IS. Although the uptake rates of the DEAE dextran-FF resins increased first and then decreased with increasing IS, they kept the extremely high level of De values(D_e/D_O > 1.1) at the their working/binding IS range. Moreover, the DEAE dextran-FF resin displayed much higher adsorption capacities and De values than commercial ungrafted resin in their working condition. Furthermore, the column results of DEAE dextran-FF resins presented higher dynamic binding capacities than and similar elution ISs with DEAE Sepharose FF to achieve similar(or even higher) recoveries suggest the excellent chromatographic column performance of the DEAE dextran-FF resins. Finally, both high recovery and purity of BSA and γ-globulin could be easily achieved using the typical DEAE dextran-FF column, FF-D60-DexD160, to separate their binary mixtures,by step gradient elution. The research has provided new insights into the practical application of the series of DEAE-dextran grafted resins in protein chromatography and proved their superiority.

Comparison of Adsorption Isotherms of Methylxanthines on C_(18) Column

A comparison of the adsorption isotherms of caffeine, theophylline and theobromine and the competitive adsorption of the three compounds on a C18 column were investigated. The experimental parameters of the equilibrium isotherms were estimated by linear and nonlinear regression analyses. The linear equation as a function of the adsorption concentration of the single compound in its solution and the competitive adsorption of a single compound in a mixed solution were then determined. The adsorption equilibrium data were then correlated to the linear, Langmuir, Freundlich, Langmuir-Freundlich and stoichiometric displacement theory for adsorption（SDT-A） isotherm models. The mixed compounds of the three compounds were competitively adsorbed on the C18 particles. The expression of stoichiometric displacement theory for adsorption was found to be more suitable for adsorption of methylxanthines on a C18 column.

Experimental Adsorption and Modelisation of CO<SUB>2</SUB>on Adsorbents Collected from Elborma Field in South Tunisia

In order to select the best adsorbant for CO2 sequestration, this study deals the interaction between clay, Triassic sandstone and Jurassic evaporate and CO2. These materials have been used as sorbents. To choose the adequate geological layers for sequestration and with minimum risk of leakage, adsorbent characterizations were investigated using X-ray diffraction, SEM and surface area analysis, structural and textural shapes of these materials have been investigated too. The elution chromatography in gaseous phase has been employed to determine the adsorption isotherms of adsorbed CO2 for each adsorbent. Then, the treatment of the experimental data allowed us to compare each CO2/adsorbent couple. The adsorption isotherms were modeled using the Langmir and Freundlich models. A thermodynamic comparison between the different adsorbents will also be provided. Experimental results show that clay and Triassic sandstone have the highest rate of adsorption amount. It has been also found that the Langmuir model is the most appropriate one to describe the phenomenon of CO2 adsorption on clay. However, for the other adsorbents (i.e. Triassic sandstone and Jurassic evaporates) the two-models are adequate.

Adsorption and Transfer Properties for Toluene and pDichlorobenzene in Dense CO_2/Silica Gel Packed Bed System by Moment Method and Time-Domain Analysis

Based on chromatographic theory, the moment method and the time-domain fitting analysis were applied to measure and evaluate the adsorption equilibrium constant and mass transfer properties (axial dispersion coefficient and effective intra-particle diffnsivity) for toluene and p-dichlorobenzene on silica gel adsorbent in the subcritical and supercritical CO2. An apparatus based on supercritical fluid chromatography was established and the experiments were performed at temperatures of 298.15-318.15 K and pressures of 7.5-17.8 MPa. The two methods have been compared. The results show that for the systems studied here the moment method can give reasonable values for both adsorption equilibrium constant and mass transfer properties, but the time-domain analysis only can obtain the adsorption equilibrium constant. The dependence of adsorption equilibrium constant and mass transfer properties on temperature and pressure was investigated.

Study on the Adsorption of Preservatives by Eyeliner Pen Packaging Materials

In order to study adsorption of preservatives by eyeliner pen package,the chemical compositions of the commercially available Eyeliner package were analyzed by infrared spectrometer.It was found that these package components were PP,PET,modified PP,modified PET,ABS,nylon,PU and so on.The adsorption effects of these components on three preservatives,i.e.phenoxyethanol,Methyl paraben and Propyl paraben have been further studied by high performance liquid chromatography.The results demonstrated that the four chemical materials PET,PP,modified PP and ABS had no adsorption on the above three preservatives.However,the component named of water diversion core which was composed of modified PET,and nylon-made cotton head have been observed of slight adsorption in this study.And components as the function of preventing liquid leakage,which was made of PU,have presented the most serious adsorption on these three preservatives,with the adsorption order as Propyl Paraben>Methyl Paraben>phenoxyethanol.

Comparison of Frontal Analysis and Elution-Curve Method for Determining Adsorption Isotherms

Adsorption isotherm is the most fundamental information related to chromatography. To calculate the parameters of Langmuir ad-sorption isotherm of thymidine, frontal analysis (FA) and elution-curve method (ECM) were adopted in reversed-phase high performance liguid chromatography (RP-HPLC). In FA, the concentration of stationary phase was measured from the elution curves and the isotherm was deter-mined by regression analysis, while the parameters by ECM were obtained by parameter optimization. The adsorption isotherms of thymidine from the two methods were very similar. The superiority of ECM over FA was that the consumption of sample was less and only one or two in-jections of sample were required.

CTA中空纤维亲和色谱的制备及其吸附性能

为探究三醋酸纤维素(CTA)中空纤维亲和色谱的吸附性能,以CTA中空纤维膜为基膜,通过水解、1,4-丁二醇二缩水甘油醚(EGDE)交联活化、接枝1,6-己二胺(HMDA)作为间隔臂对膜表面进行改性,然后以亚氨基二乙酸(IDA)为配基,螯合Cu^(2+)制备了改性CTA中空纤维亲和色谱.对于γ-球蛋白的静态吸附研究表明:当吸附液γ-球蛋白质量浓度为1 mg/mL、离子浓度为0.2 mol/L和pH=8时,有最大静态吸附容量2.4 mg/cm^(3).且其吸附过程符合Langmuir等温吸附模型.对于γ-球蛋白的动态吸附研究表明:在实验研究的范围内,不同流速下的穿透曲线都呈现出类似“S”型,流速并不影响CTA中空纤维亲和色谱上γ-球蛋白的结合能力;γ-球蛋白的动态吸附容量随其初始浓度的增加而增加.

LN树脂对溶液中钐和钆的静态吸附和色层柱分离

探究LN树脂对Sm(Ⅲ)和Gd(Ⅲ)的吸附效果,考察了时间、酸度和温度对树脂吸附量的影响,对吸附过程的吸附动力学和吸附热力学进行了研究,并测定了相关热力学参数ΔH、ΔS以及ΔG。结果表明,LN树脂在298 K下对Sm(Ⅲ)和Gd(Ⅲ)的吸附可在2 min后达到平衡,酸度越小平衡吸附量越大,且随温度升高平衡吸附量也逐渐升高。使用LN树脂色层柱进行了钐和钆的分离试验,Sm(Ⅲ)在0.75 mol/L HNO_(3)酸度下洗脱,Gd(Ⅲ)在1.0 mol/L HNO_(3)酸度下洗脱,不同洗脱液流速对柱分离效果的影响结果表明,流速为0.53 mL/min时分离效果最好。

含氟富氮多孔有机聚合物的合成及其对水中全氟辛酸的去除

全氟辛酸(PFOA)在自然环境中难以降解,会通过富集渗透污染水体和土壤,从而对自然环境和人体健康造成影响。开发成本低、效率高、环保的吸附剂实现环境水体中PFOA的高效吸附去除是解决PFOA污染的有效途径之一。本研究采用无溶剂一锅法设计、制备了一种含氟富氮多孔有机聚合物(POP-3F),通过引入氟原子增加了材料的疏水性,增加了主客体分子间的疏水作用、氟-氟相互作用,提升了材料对PFOA的吸附效果。使用扫描电子显微镜(SEM)、傅里叶变换红外光谱(FT-IR)、X-射线衍射仪(XRD)、固体核磁(ssNMR)、X射线光电子能谱仪(XPS)、热分析系统(TGA)等对POP-3F进行了表征。结合液相色谱-串联质谱法(LC-MS/MS),研究了POP-3F在不同pH、盐浓度和腐植酸条件下对PFOA的吸附性能。在pH值为2时,POP-3F对PFOA的去除率最高达到98.6%,可用于去除酸性工业废水中的PFOA。并且POP-3F对于PFOA的去除率几乎不受NaCl和腐植酸浓度的影响,在加入NaCl后,POP-3F表面会形成双电层,可以削弱POP-3F与PFOA之间的静电相互作用,去除率仅下降了1%。腐植酸与PFOA存在竞争吸附,在高浓度腐植酸条件下,POP-3F对PFOA的去除率仅下降了0.73%。在最佳pH条件下考察了吸附等温线和吸附动力学,通过数学模型拟合了实验结果,探究了吸附机理。结果显示,POP-3F的理论容量为191 mg/g,高于活性炭和其他多数吸附剂,表现出较高的吸附容量。此外,POP-3F对PFOA的吸附去除几乎不受基质种类的影响,在模拟自然水中吸附效果略有降低(仅降低0.1%),经过5次吸附-解吸循环后,对PFOA的去除率仅微幅下降(降低0.67%),表明其具有循环使用和可再生性,在实际PFOA污染废水处理中具有广阔的应用前景。

混合型离子交换反相吸附固相萃取-超高效液相色谱-三重四极杆质谱法测定水中23种非甾体抗炎药的残留

非甾体抗炎药(NSAIDs)作为一种新型有机污染物,在环境水体中普遍检出,对生态系统及人体健康造成潜在的威胁,开发准确、可靠的测定水中痕量非甾体抗炎药的检测方法至为重要.本文采用Oasis MCX固相萃取柱对水样进行富集,建立测定水中23种非甾体抗炎药的超高效液相色谱-三重四极杆质谱分析方法.采用酸性条件(pH=4)萃取水样,上样的流速为2 mL·min^(−1),用4 mL甲醇-4 mL5%氨水甲醇进行洗脱,浓缩定容后用ACQUITY UPLCTM BEH C18柱(2.1 mm×100 mm,1.7μm),以2 mmol·L^(−1)乙酸铵+0.05%(V/V)甲酸水溶液-乙腈作为流动相进行梯度洗脱,多反应选择离子监测(MRM)模式进行检测,内标法定量.23种NSAIDs在相关线性范围内线性良好(r=0.9951—0.9992),回收率为80.2%—120%,相对标准偏差为0.4%—12.5%,方法检出限为0.20—4.84 ng·L^(−1).将该方法应用于10份地表水的检测,结果显示有10种NSAIDs检出,质量浓度在ND—83.5 ng·L^(−1)之间.该方法简单、灵敏、高效,可应用于环境水体中NSAIDs的检测.

金属有机框架富集-高效液相色谱法测定预包装果蔬制品中双酚A含量

目的:建立金属有机框架富集-高效液相色谱法测定预包装果蔬制品中双酚A的方法。方法:基于QuEChERS处理技术,通过优化提取和净化条件,利用金属有机框架材料富集果蔬样品中的双酚A,采用高效液相色谱法测定。结果:在优化条件下,双酚A在10~1000μg·L^(-1)具有良好的线性关系,相关系数(R^(2))大于0.9990,检出限为0.1μg·kg^(-1),定量限为0.3μg·kg^(-1)。不同果蔬基质的加标回收率在80.5%~105.2%,相对标准偏差为9.6%。不同果蔬基质效应对定量检测影响不显著(|ME|<10%)。结论:该方法灵敏度高,不需要内标和固相萃取装置,操作简便,可满足果蔬中双酚A的检测需求,为食品中双酚A的检测提供了一种经济、便捷的新思路。

新型碳分子筛在工业源挥发性有机物测定中的应用

制备新型碳分子筛Scalpha 1500,并采用Scalpha 1500代替进口碳分子筛Carboxen 1000组合成新的吸附管(CB1500吸附管)。采用扫描电子显微镜(SEM)、X射线能谱法(EDS)、氮气吸附-脱附等温线法和X射线衍射法(XRD)对两种碳分子筛的表观形貌、元素组成、孔隙结构以及晶相构成进行表征。利用热脱附-气相色谱-质谱法(TD-GC-MS),比较CB1500吸附管与HJ 734-2014推荐组合三吸附管(Carbon 300吸附管)对挥发性有机物(VOCs)的测试性能。吸附管的最优解吸参数为解吸温度300℃、解吸时间6 min、解吸流量50 mL·min^(−1),在该条件下,两种吸附管具有相近的本底值、解吸性能及穿透性能。结果表明,CB1500及Carbon 300吸附管中24种VOCs的质量在5~100 ng内与对应的峰面积呈线性关系,检出限(3S/N)分别为0.4~4.8μg·m^(−3)和0.4~4.6μg·m^(−3)。按照标准加入法进行回收试验,CB1500及Carbon 300吸附管中24种VOCs的回收率分别为93.0%~107%和92.0%~113%,除乳酸乙酯外其他23种VOCs测定值的相对标准偏差(n=7)均小于5.0%。采用两种吸附管对广州某工业园区固定污染源废气进行采样分析,CB1500及Carbon 300吸附管中24种VOCs均有检出,检出量分别为2.3~21.1μg·m^(−3)和2.4~21.3μg·m^(−3)。上述结果说明新型碳分子筛Scalpha 1500可代替进口碳分子筛Carboxen 1000组合成新的吸附管采集VOCs,可极大降低采样成本。

温度梯度相互作用色谱在聚烯烃表征中的应用

研究了高温-温度梯度相互作用色谱(HT-TGIC)在聚烯烃表征中的应用,并与结晶分级技术进行了对比,同时分析了实验条件对HT-TGIC曲线的影响。实验结果表明,相比结晶分级技术,HT-TGIC在表征结晶度较低或完全无定形树脂时具有明显优势。HT-TGIC可用于定量表征聚烯烃树脂及其共混物的化学组成分布,并具有良好分辨率。优化的操作条件为:尽可能快的冷却速度、升温速率/淋洗流量的比值在一定范围内、动态降温、较小的动态吸附流量、冷却循环最终温度高于结晶温度。利用辛烯含量差与HT-TGIC淋洗峰偏离值呈线性关系,可快速确定共聚单体含量,包括高共聚单体含量树脂。

CL-Cyanex272萃取色层法深度净化钴溶液

以苯乙烯为单体,二乙烯苯为交联剂,Cyanex272为萃取剂,采用乳液悬浮聚合法制备CL-Cyanex272萃淋树脂。采用静态吸附法探究了Co浓度、温度、pH、皂化度、时间等因素对CL-Cyanex272萃淋树脂吸附Co、Ni、Mg的影响;采用萃取色层法探究了连续动态过程中萃淋树脂对含Co溶液净化的影响。结果表明:当料液pH=6、皂化度为100%时,CL-Cyanex272萃淋树脂对Co的吸附量达21.4 mg g;控制皂化度≥70%、料液pH≥5时,Co与Ni、Co与Mg的分离效果较好,其分离系数分别达到1697和18;动态吸附试验中CL-Cyanex272萃淋树脂可将料液中Co的浓度从80.15%提纯到99.9996%。本研究为CL-Cyanex272萃淋树脂用于工业纯化Co溶液提供良好的依据。

竞争性吸附法降低林可霉素B组分的工艺研究

生产林可霉素的传统工艺为萃取法,该方法不能有效去除B组分杂质,目前较新颖的树脂法虽能将B组分去除,但效率不够高。本文以竞争性吸附原理为指导,通过连续上柱的方式,放大树脂对产品与杂质的分离能力,从而实现了B组分的高效去除。本研究也为竞争性吸附法在其他生化产品分离领域的应用提供了借鉴。