Preparation and adsorption properties of PAA-grafted cellulose adsorbent for low-density lipoprotein from human plasma

A new low-density lipoprotein (LDL) adsorbent with good adsorption performance has been obtained by use of a simple preparation procedure. Graft copolymerization of acrylic acid (AA) on to macroporous cellulose beads was performed with cerium ammonium nitrate (CAN) as a redox initiator. The effects of initiator concentration, monomer concentration, and reaction time on grafting were examined. In adsorption tests, several factors affecting adsorption of lipoproteins were investigated in detail. In-vitro study showed that this adsorbent could remove total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C), and triglyceride (TG) at levels of 5.55, 4.46, and 2.48 mg g⁻¹, respectively, from human plasma without substantially affecting high-density lipoprotein-cholesterol (HDL-C) and total proteins (TP). The adsorbent prepared in this work might be further studied for potential clinical application.     

一种新型低密度脂蛋白吸附剂的制备

通过在环氧化的交联聚乙烯醇球上固载多乙烯多胺和磺酸基团的方法制备一种新型的低密度脂蛋白吸附剂.环氧化的交联聚乙烯醇球首先与乙二胺或二乙烯三胺、三乙烯四胺及四乙烯五胺等多乙烯多胺进行胺化反应,由此获得不同长度悬臂,而后将胺化的环氧化的交联聚乙烯醇球与DMF/ClSO₃H反应,从而固载磺酸基团.磺酸基团的固载量随交联度的减小和聚乙烯醇浓度的增大而增大.初步研究证实,该类吸附剂具有较大的吸附量和较好的选择性.     

A heparin modified polypropylene non‐woven fabric membrane adsorbent for selective removal of low density lipoprotein from plasma

In the present work, a new porous low density lipoprotein (LDL) adsorbent membrane is prepared by ⁶⁰Co γ‐ray irradiation‐induced grafting copolymerization of polypropylene (PP) non‐woven fabric with acrylic acid, followed by immobilizing heparin covalently. The amount of carboxyl group and heparin on the resultant PP non‐woven fabric is determined by titration and colorimetry, respectively. The new adsorbent membrane is characterized by attenuated total reflection Fourier transform infrared spectroscopy, scanning electron microscope, and contact angle microscopy. Static adsorption and hemoperfusion tests indicate this new adsorbent can efficiently and selectively remove LDL from human plasma. Meanwhile, good adsorption of triglyceride (TG) is also obtained. The best result is achieved by the adsorbent membrane P_0.45‐A₁₅‐H, where 33.3 ± 2.9 µg of LDL‐C, 14.7 ± 1.9 µg of high density lipoprotein cholesterol (HDL‐C), 64.9 ± 4.3 µg of total cholesterol (TC), and 202.4 ± 5.7 µg of TG are removed from human plasma per square centimeter. Hemocompability and toxicity tests show this new adsorbent membrane has good blood compatibility and low toxicity. Considering the adsorbent performance, safety, low cost, and simple preparation, this new adsorbent membrane has potential clinical application for removal of LDL. Copyright © 2013 John Wiley & Sons, Ltd.     

A Modified Chitosan Adsorbent for Selective Removal of Low Density Lipoprotein

A modified chitosan adsorbent was synthesized through a simple preparation procedure,and it demonstrated good adsorption performance for selective removal of low density lipoprotein in human plasma. Phase inversion technique was employed to form chitosan beads, to which epoxy groups were then introduced by reacting with ethyleneglycol diglycidylether, and tryptophan was subsequently coupled to the epoxy-activated beads.     

磺化羟乙基化交联壳聚糖对血清中低密度脂蛋白的吸附性能研究

磺化羟乙基化，交联壳聚糖，低密度脂蛋白，高密度脂蛋白，总蛋白，高脂蛋白血症     

Ellipsometry Studies of Lipoprotein Adsorption

The adsorption of a number of lipoproteins, i.e., low-density lipoprotein (LDL), oxidized LDL (oxLDL), high-density lipoprotein (HDL), and lipoprotein (a), at silica and methylated silica as well as at the latter surface modified through adsorption of proteoheparan sulfate, was investigated with in situ ellipsometry at close to physiological conditions. It was found that LDL, oxLDL, HDL, and lipoprotein (a) all adsorbed more extensively at silica than at methylated silica. Upon exposure of the methylated silica surface to proteoheparan sulfate, this proteoglycan adsorbs through its hydrophobic moiety, thereby forming a layer similar to that in the biological system, with the polysaccharide chains forming brushes oriented toward the aqueous solution. Analogous to the biological system, both lipoprotein (a) and LDL were found to deposit at such surfaces, the latter particularly in the simultaneous presence of Ca(2+). After HDL pre-exposure, however, no LDL deposition was observed, even at high LDL and Ca(2+) concentrations. These findings correlate well with those obtained from clinical investigations on risk factors for atherosclerosis. Copyright 2000 Academic Press.     

一种新型低密度脂蛋白吸附剂的制备

研究表明,人体血浆中低密度脂蛋白(LDL)的含量过高会引起动脉硬化,进而诱发各种心脑血管疾病^[1].近年来,采用血液净化吸附剂去除LDL受到了广泛的关注^[2～10].目前临床上使用的吸附剂主要有固载LDL抗体的琼脂糖吸附剂及固载肝素或磺化葡聚糖的纤维素吸附剂,它们虽有较好的吸附效果,但由于存在配基昂贵、吸附剂成本高及机械强度差等问题,这些吸附剂的应用受到了很大的限制.本文以具有良好机械强度和血液相容性的聚乙烯醇(PVA)大孔珠状树脂为载体,以廉价易得的吲哚-3-乙酸(IAA)为配基,分别以不同长度的多胺为悬臂,制备了一种新型LDL吸附剂,并初步考察了其对LDL的吸附性能.     

Application of poly(dimethylsiloxane)/glass microchip for fast electrophoretic separation of serum small,dense low-density lipoprotein

Due to the mounting evidence of altered low-density lipoprotein (LDL) size in several disease states, there has been an increasing interest in developing new analytical methods for small, dense low-density lipoprotein (sdLDL) for diagnosis. The present report demonstrates that sdLDL analysis can be performed in a poly(dimethylsiloxane) (PDMS/glass) microchannel. n-Dodecyl β-d-maltoside (DDM) was utilized to alter channel surface to make it become hydrophilic and nonionic, thus reducing the interaction between the protein and the surface. Moreover, hydroxypropylcellulose (HPC) was added into the running buffer to suppress the adsorption of analytes and also to serve as a sieving matrix. Under optimal conditions, two baseline separations of lipoproteins including high-density lipoprotein (HDL), sdLDL, and lLDL were achieved with different selectivity. LDL particles shown on the electropherogram were also identified by several procedures. This method affords high separation speed and high reproducibility. The intraassay and interassay RSDs of lipoprotein migration times were in the range of 2.01–2.45%. The variation of serum sdLDL of a patient between prior treatment and post-treatment was assessed by this method. This system has the potential for rapid and sensitive detection of different LDL forms, and thus will be applicable to clinical diagnosis.     

Efficient Removal of Pb(II) from Aqueous Medium Using Chemically Modified Silica Monolith

The adsorptive removal of lead (II) from aqueous medium was carried out by chemically modified silica monolith particles. Porous silica monolith particles were prepared by the sol-gel method and their surface modification was carried out using trimethoxy silyl propyl urea (TSPU) to prepare inorganic–organic hybrid adsorbent. The resultant adsorbent was evaluated for the removal of lead (Pb) from aqueous medium. The effect of pH, adsorbent dose, metal ion concentration and adsorption time was determined. It was found that the optimum conditions for adsorption of lead (Pb) were pH 5, adsorbent dose of 0.4 g/L, Pb(II) ions concentration of 500 mg/L and adsorption time of 1 h. The adsorbent chemically modified SM was characterized by scanning electron microscopy (SEM), BET/BJH and thermo gravimetric analysis (TGA). The percent adsorption of Pb(II) onto chemically modified silica monolith particles was 98%. An isotherm study showed that the adsorption data of Pb(II) onto chemically modified SM was fully fitted with the Freundlich and Langmuir isotherm models. It was found from kinetic study that the adsorption of Pb(II) followed a pseudo second-order model. Moreover, thermodynamic study suggests that the adsorption of Pb(II) is spontaneous and exothermic. The adsorption capacity of chemically modified SM for Pb(II) ions was 792 mg/g which is quite high as compared to the traditional adsorbents. The adsorbent chemically modified SM was regenerated, used again three times for the adsorption of Pb(II) ions and it was found that the adsorption capacity of the regenerated adsorbent was only dropped by 7%. Due to high adsorption capacity chemically modified silica monolith particles could be used as an effective adsorbent for the removal of heavy metals from wastewater.     

聚(丙烯酸-co-丙烯酰胺)/蒙脱土/腐殖酸钠复合物对Pb2+的吸附性能

用制备的聚(丙烯酸-co-丙烯酰胺)/蒙脱土/腐殖酸钠复合吸附剂,研究了溶液pH值、吸附时间和Pb2+溶液初始浓度等因素对重金属Pb2+的吸附性能,探讨了复合吸附剂对Pb2+的吸附机理。结果表明,在pH值为6.0、吸附时间2 h、Pb2+溶液初始浓度0.01 mol/L和吸附剂用量0.10 g的条件下,复合吸附剂对Pb2+的吸附量达到364.05 mg/g,平衡所需的时间为15 min。与蒙脱土相比,复合吸附剂具有更高的吸附容量和更快的吸附速率。     

A study of the alumina-silica gel adsorbent for the removal of silicic acid from geothermal water: increase in adsorption capacity of the adsorbent due to formation of amorphous aluminosilicate by adsorption of silicic acid

Two kinds of adsorbents (Si adsorbent and Al adsorbent) for the removal of silicic acid from geothermal water to retard the formation of silica scales were prepared using silicic acid contained in geothermal water. The Si adsorbent was prepared by evaporating geothermal water, and the Al adsorbent was prepared by evaporating geothermal water after the addition of aluminum chloride. The specific surface area of the Si adsorbent was small and it's adsorption capacity of silicic acid was low. Although the specific surface area of the Al adsorbent was also small, it was significantly increased by the adsorption of silicic acid and it's adsorption capacity was high. Based on the change in the local structure of aluminum ion by the adsorption of silicic acid, the Al adsorbent was considered to be silica particles covered with crystalline aluminum hydroxide. Moreover, it was concluded that the increase in the specific surface area of the Al adsorbent and the decrease in the zeta potential were due to the formation of an amorphous aluminosilicate with a large surface area and a negative charge (one 4-coordinated Al) by the reaction between aluminum ions and silicic acids.     

响应面法优化巴旦木壳对废水Pb、Cu和Cd的吸附及同时测定

研究废弃巴旦木壳对模拟废水中Pb、Cu和Cd的去除率。在单因素试验的基础上,采用响应面法对吸附剂投加量、吸附时间和pH值3因素进行优化。实验结果表明,最佳吸附条件为Pb：为吸附剂投加量0.4g、吸附时间49.38min、pH值为9.96;Cu：吸附剂投加量0.4g、吸附时间49.91min、pH值为10.13;Cd：吸附剂投加量0.4g、吸附时间49.83min、pH值为10.42;在此条件下,Pb、Cu和Cd的去除率分别为87.42%、73.49%和85.11%。采用偏最小二乘法(PLS)对Pb、Cu和Cd模拟混合试样吸附后的溶液进行同时测定,计算得出吸附剂对Pb、Cu和Cd的去除率分别为83.2%、66.0%和83.3%。     

Recovery of Th(IV) from aqueous solution by reassembled collagen-tannin fiber adsorbent

A novel adsorbent, collagen immobilized tannin adsorbent (CITA), was prepared and its adsorption behaviors to Th(IV) were investigated. CITA was in fibrous state due to the reassembly of collagen molecules by the inducement of tannin. This adsorbent loaded a greater amount of tannin and exhibited higher adsorption capacity to Th(IV) than the tannin immobilized adsorbent prepared from collagen fiber. The adsorption of CITA to Th(IV) is mainly attributed to surface complexation, which is a pH- rather than an ionic strength-dependent process. The adsorption kinetics and isotherms were described by pseudo-second-order rate model and Freundlich equation, respectively. Column adsorption studies indicated that CITA is available for effectively recovering Th(IV) from aqueous solution.     

CO2 capture by polyethylenimine-modified fibrous adsorbent

This work focuses on developing a novel adsorbent for CO2 capture, by coating polyethylenimine (PEI) on glass fiber matrix and using epichlorohydrin (ECH) as cross-linking agent. The physicochemical properties of the fibrous adsorbent were characterized. The CO2 adsorption capacity was evaluated. Factors that affect the adsorption capacity of the fibrous adsorbent were studied. The experimental results show that this fibrous PEI adsorbent exhibits a much higher adsorption capacity for CO2 compared with another PEI fiber prepared in our previous work, which employed epoxy resin as the cross-linking agent. A CO2 adsorption capacity as high as 4.12 mmol CO2/g of adsorbent was obtained for this fibrous PEI adsorbent at 30 degrees C, equal to 13.56 mmol CO2/g of PEI, with a PEI/ECH ratio of 20:1. The adsorbent can be completely regenerated at 120 degrees C.     

The downsizing of a TSA system for an air purification unit using a high flow rate method

A high flow rate type air purification unit to reduce the size of adsorption vessel was developed. The setting area of air purification unit and the cost of adsorption vessel were reduced to 65% and 70% respectively. The downsizing was achieved by the way that a mass transfer zone (MTZ) was formed in the whole region of adsorbent layer and by the development of adsorbent for the high flow rate process. As regards the adsorbent, the adsorption performance to realize the process was investigated. Then the adsorbent which has larger size and higher adsorption performance was developed and TSA process experiment was carried out. As the result, the realization of the high flow rate process was made sure experimentally.     

磷酸铝吸附除水中氟的研究

采用静态吸附法研究了比表面为308m2/g的无定形磷酸铝吸附除氟性能,研究了接触时间、pH值、吸附剂量等对吸附的影响。结果表明,磷酸铝吸附除氟高效、迅速,30min内可以接近最大吸附量。对含氟50mg/g的溶液,优化条件下的最大除氟率约93%。研究了吸附与溶液pH的关系,得到了优化pH值并解释了吸附机理。吸附的最佳pH值约为5.5。用拟二级动力学方程描述了吸附速率并计算了速率常数。用Langmuir方程拟合了吸附等温线,计算的饱和吸附量为53.5mg/g。吸附剂量对分配系数的影响表明吸附剂表面是不均匀的。     

Synthesis and Properties of Surface Molecular Imprinting Adsorbent for Removal of Pb<Superscript>2+</Superscript>

A new chitosan imprinting adsorbent using diatomite as core material was prepared by using the surface molecular imprinting technology with the Pb²⁺ as imprinted ion. The preparation process conditions of the surface molecular imprinting adsorbent were studied. The adsorbent was characterized by using Fourier transform infrared (FTIR) spectrum. FTIR spectrum indicated that it was cross-linked by epichlorohydrin. The new imprinting adsorbent could provide a higher adsorption capacity for Pb²⁺, which reached 139.6 mg/g increasing 32.3% compared with cross-linking chitosan adsorbent (the initial Pb²⁺ concentration of 600 mg/L). The adsorption velocity was quick and the equilibration time of the imprinting adsorbent for Pb²⁺ was 3 h that shortened about 40% compared with cross-linking chitosan adsorbent. It had a more wide pH range of 5–7 than that of cross-linking chitosan adsorbent. The new imprinting adsorbent can be reused for up to ten cycles without loss of adsorption capacity. In the kinetics and isotherm study, the pseudosecond order model and Langmuir model could represent the adsorption process.     

聚对羟基苯乙烯吸附树脂的合成及对咖啡因的吸附机理研究

用正庚烷／正丁醇、正庚烷／环己醇等混合溶剂为致孔剂合成了一系列具有不同比表面积的对羟基苯乙烯－二乙烯苯共聚物,并研究了这些共聚物对咖啡因的吸附性能。结果表明：凝胶型树脂吸附量小,而大孔型树脂吸附量大且比表面积对树脂的吸附量影响不明显。ＩＲ证实这类树脂吸附咖啡因时,氢键起了非常重要的作用。     

Diethylenetriamine-grafted poly(glycidyl methacrylate) adsorbent for effective copper ion adsorption

Amine-functionalized adsorbents have attracted increasing interest in recent years for heavy metal removal. In this study, diethylenetriamine (DETA) was successfully grafted (through a relatively simple solution reaction) onto poly(glycidyl methacrylate) (PGMA) microgranules to obtain an adsorbent (PGMA-DETA) with a very high content of amine groups and the PGMA-DETA adsorbent was examined for copper ion removal in a series of batch adsorption experiments. It was found that the PGMA-DETA adsorbent achieved excellent adsorption performance in copper ion removal and the adsorption was most effective at pH>3 in the pH range of 1-5 examined. X-ray photoelectron spectroscopy (XPS) revealed that there were different types of amine sites on the surfaces of the PGMA-DETA adsorbent but copper ion adsorption was mainly through forming surface complexes with the neutral amine groups on the adsorbent, resulting in better adsorption performance at a higher solution pH value. The adsorption isotherm data best obeyed the Langmuir-Freundlich model and the adsorption capacity reached 1.5 mmol/g in the case of pH 5 studied. The adsorption process was fast (with adsorption equilibrium time less than 1-4 h) and closely followed the pseudo-second-order kinetic model. Desorption of copper ions from the PGMA-DETA adsorbent was most effectively achieved in a 0.1 M dilute nitric acid solution, with 80% of the desorption being completed within the first 1 min. Consecutive adsorption-desorption experiments showed that the PGMA-DETA adsorbent can be reused almost without any loss in the adsorption capacity.     

Adsorption behavior of Pd(II) ions from aqueous solution onto pyromellitic acid modified-UiO-66-NH2

A new adsorbent was successfully fabricated by chemically linking pyromellitic acid onto a zirconium-based metal-organic framework composite for selective adsorption of Pd(II) from an aqueous solution. The adsorbent was characterized by Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller equation and scanning electron microscope. The adsorption capacity, selectivity and repeatability of the adsorbent were tested by batch experiments. The optimum pH was 2.0, and the maximum adsorption capacity at room temperature was 226.1 mg/g. In the kinetic experiments, the adsorption process achieved equilibrium within 5 h and generally conformed to the quasi-second kinetics and Freundlich isotherm model. The N-H and OH groups on the adsorbent interacted with Pd(II) by electrostatic and coordination action. The adsorbent maintained excellent adsorption capacity after at least 5 cycles. At the same time, the selectivity of the adsorbent in aqueous solution is excellent from interfering ions. Therefore, the new adsorbent will have an obvious application prospect on the recovery of palladium.