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High Adsorption Capacity (high + adsorption_capacity)
Selected AbstractsSynthesis of Core/Shell Colloidal Magnetic Zeolite Microspheres for the Immobilization of TrypsinADVANCED MATERIALS, Issue 13 2009Yonghui Deng Magnetic zeolite microspheres are synthesized by combining sol-gel synthesis and vapor-phase transport. The microspheres, which have magnetite cores and crystalline zeolite shells (see figure), exhibit super-paramagnetism and a high adsorption capacity for trypsin. Trypsin-adsorbed microspheres digest proteins very efficiently (in only 15,s) in the presence of microwave radiation. [source] Preparation and adsorption behavior of a cellulose-based, mixed-mode adsorbent with a benzylamine ligand for expanded bed applicationsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Dong Gao Abstract A novel mixed-mode expanded bed adsorbent with anion-exchange properties was explored with benzylamine as the functional ligand. The cellulose composite matrix, densified with stainless steel powder, was prepared with the method of water-in-oil suspension thermal regeneration. High activation levels of the cellulose matrix were obtained with allyl bromide because of the relative inertness of the allyl group under the conditions of the activation reaction. After the formation of the bromohydrin with N -bromosuccinimide and coupling with benzylamine, the activated matrix was derived to function as a mixed-mode adsorbent containing both hydrophobic and ionic groups. The protein adsorption capacity was investigated with bovine serum albumin as a model protein. The results indicated that the prepared adsorbent could bind bovine serum albumin with a high adsorption capacity, and it showed salt tolerance. Effective desorption was achieved by a pH adjustment across the isoelectric point of the protein. The interactions between the cell and adsorbent were studied, and the bioadhesion was shielded by the adjustment of the salt concentration above 0.1M. Stable fluidization in the expanded bed was obtained even in a 2% (dry weight) yeast suspension. The direct capture of target proteins from a biomass-containing feedstock without extra dilution steps could be expected with the mixed-mode adsorbent prepared in this work, and this would be especially appropriate for expanded bed adsorption applications. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Production of activated carbon from agricultural by-productsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2008Panagiota Paraskeva Abstract The production of activated carbon from agricultural by-products is a research field of increasing interest as it deals with the problem of the disposal of agro-residues, at the same time producing an added-value product that can be used in a number of environmental applications. The paper presents an overview of the latest developments in processes for the production of activated carbon from agricultural by-products, with emphasis on the methodology applied, the effect of critical process parameters such as retention time, temperature, chemical to material ratio, as well as the adsorbing capacity of the activated carbons produced in removing select compounds from synthetic and real wastewaters. Agricultural by-products can be a source for activated carbon production with high surface areas and high adsorption capacity. Copyright © 2008 Society of Chemical Industry [source] Behaviour and mechanism of Zn(II) adsorption on Chinese loess at dilute slurry concentrationsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 5 2008Xiaowu Tang Abstract BACKGROUND: Zn(II) is commonly present in mining drainage in developing countries. Since loess is abundant and always located near mining sites in China, it would be useful to investigate the possibility and efficiency of using loess to remove Zn(II) from aqueous solution. RESULTS: The Zn(II) adsorption capacity of Chinese loess was determined as 215.9 mg g,1. The adsorption followed pseudo-second-order kinetics and took place mainly by surface diffusion. Generally, higher initial pH and solute concentration resulted in higher % Zn(II) removal, while higher temperature and slurry concentration led to lower % Zn(II) removal. A thermodynamic study revealed that the adsorption process was exothermic, with the predicted enthalpy change ranging from ,20.87 to ,4.06 kJ mol,1. With the assistance of X-ray photoelectron spectroscopy and X-ray diffraction, the high adsorption capacity was ascribed to the growth of micro-organisms and mineral constituents such as kaolinite and goethite. CONCLUSION: Chinese loess proved effective for Zn(II) adsorption in this study. The optimal adsorption conditions included pH > 3.0, temperature ,15 °C and contact time , 400 min. As an abundant natural soil in arid areas with very low population density, it would be appropriate to develop this material into a wastewater-purifying agent. Copyright © 2008 Society of Chemical Industry [source] Adsorption Kinetics and Thermodynamics of Acid Dyes on a Carboxymethylated Chitosan-Conjugated Magnetic Nano-AdsorbentMACROMOLECULAR BIOSCIENCE, Issue 3 2005Yang-Chuang Chang Abstract Summary: The monodisperse chitosan-conjugated Fe3O4 nanoparticles with a mean diameter of 13.5 nm were fabricated by the carboxymethylation of chitosan and its covalent binding onto Fe3O4 nanoparticles via carbodiimide activation. The carboxymethylated chitosan (CMCH)-conjugated Fe3O4 nanoparticles with about 4.92 wt.-% of CMCH had an isoelectric point of 5.95 and were shown to be quite efficient as anionic magnetic nano-adsorbent for the removal of acid dyes. Both the adsorption capacities of crocein orange G (AO12) and acid green 25 (AG25), as the model compounds, decreased with increasing pH, and the decreasing effect was more significant for AO12. On the contrary, the increase in the ionic strength decreased the adsorption capacity of AG25 but did not affect, obviously, the adsorption capacity of AO12. By the addition of NaCl and NaOH, both AO12 and AG25 could desorb and their different desorption behavior could be attributed to the combined effect of pH and ionic strength. From the adsorption kinetics and thermodynamics studies, it was found that both the adsorption processes of AO12 and AG25 obeyed the pseudo-second-order kinetic model, Langmuir isotherm, and might be surface reaction-controlled. Furthermore, the time required to reach the equilibrium for each one was significantly shorter than those using the micro-sized adsorbents due to the large available surface area. Also, based on the weight of chitosan, the maximum adsorption capacities were 1,883 and 1,471 mg,·,g,1 for AO12 and AG25, respectively, much higher than the reported data. Thus, the anionic magnetic nano-adsorbent could not only be magnetically manipulated but also possessed the advantages of fast adsorption rate and high adsorption capacity. This could be useful in the fields of separation and magnetic carriers. Acid dyes adsorption onto the CMCH-conjugated Fe3O4 nanoparticles. [source] Development of Cellulose-DNA ImmunoadsorbentARTIFICIAL ORGANS, Issue 2 2002Deling Kong Abstract: The aim of this study was to prepare a DNA immunoadsorbent for the specific, extracorporeal removal of anti-DNA antibodies from the blood of patients with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Two kinds of cellulose beads were applied as a carrier. Calf thymus DNA was covalently coupled to the carrier using the epichlorohydrin method. Efforts were focused on optimization of conditions for activation and coupling, trying to couple as much DNA as possible to a certain amount of carrier. It was found that the activation level increased with the increase of NaOH concentration and the amount of epichlorohydrin used. The mole of epichlorohydrin must be in excess of that of NaOH because excess NaOH could react further with the epoxy groups in the beads resulting in a decrease of activation level. High activation level could be obtained in a medium of 3.0 M NaOH. The DNA coupling was found to be mainly temperature and pH dependent. Using 0.1 M Tris-HCl buffer, pH 8 at a temperature of 50,90°C, more than 3 mg of DNA could be coupled to 1 ml of wet beads. Prolonging the coupling reaction under 50°C to 72 h resulted in the same coupling capacity as that obtained under 90°C. To evaluate the adsorption ability for anti-DNA of this immunoadsorbent, batch and circulation tests were applied using SLE patient plasma. The immunoadsorbents showed excellent adsorption capacity, especially the cellulose with smaller size (200,300 ,m). The incubation of 20 ml of patient's plasma with 1 ml of adsorbent resulted in an 80% decline in the anti-DNA antibody level. In the circulation tests, 30 ml of plasma was circulated through a column containing 3 ml of adsorbent. The maximum decline in anti-DNA level, 80%, was obtained after 60 min. Such high adsorption capacity and high adsorption rate suggest this immunoadsorbent may be used for treatment. For comparison, 1,4-butanediol diglycidyl ether activation method and other DNA sources were tested with the same protocol. [source] Equilibrium and heat of adsorption of phosphine on CaCl2 -modified molecular sieveASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 5 2009Qiongfen Yu Abstract Adsorption characteristics of the virgin and CaCl2 -immersed molecular sieves at 298 K were investigated to select the adsorbent with high adsorption capacity to phosphine. Adsorption isobars and adsorption isotherms over the phosphine partial pressure and temperature ranged 0 , 1000 Pa and 298 , 343 K were measured. The adsorption equilibrium data for phosphine at various temperatures were fitted to Langmuir and Freundlich isotherm models and their isosteric heats of adsorption were determined by the Clausius-Clapeyron equation. It was found the Freundlich was more suitable for description of phosphine adsorption process through calculating average absolute relative error, and the fitted result about Langmuir model showed the heterogeneous characteristics of modified adsorbent. The isosteric heat of adsorption was about 15 kJ/mol, which indicated adsorptive phosphine removal performance may be a dominant of physical adsorption being easy for desorption. The isosteric heat of adsorption decreased with an increase of the surface loading on CaCl2/5A, which means that CaCl2/5A molecular sieve had an energetically heterogeneous surface. The present study confirmed that the CaCl2/5A molecular sieves would be one of the candidates for separation and recycle of phosphine. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Removal of Copper-phthalocyanine from Aqueous Solution by Cationically Templated MCM-41 and MCM-48 Nanoporous AdsorbentsCHINESE JOURNAL OF CHEMISTRY, Issue 11 2008Mansoor ANBIA The effect of cationic template on the adsorption of copper-phthalocyanine-3,4,,4,,,4,,,-tetrasulfonic acid tetrasodium salt [Cu(tsPc),4·4Na+] in MCM-41 and MCM-48 mesoporous materials was investigated, using cetyltrimethylammonium bromide (CTAB) as the cationic template and tetraethyl-orthosilicate as the silica source for synthesis of mesoporous materials. The properties of synthesized samples were characterized with XRD-low angle and scanning electron microscopy. The as-synthesized mesoporous samples were used for the separation of Cu(tsPc),4·4Na+ from aqueous solution, which showed very high adsorption capacity for it. [source] | |||||||||||||