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Adsorption Experiments (adsorption + experiment)
Kinds of Adsorption Experiments Selected AbstractsAdsorption of SO2 on Activated Carbon for Low Gas ConcentrationsCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 5 2007P. Zhang Abstract Adsorption experiments of SO2 on activated carbon has been carried out for low concentrations (about 100,ppm) at room temperature (15 to 33,°C) with varying humidity in the air. The breakthrough curves show that at high relative humidity or relative higher SO2 concentration, the load capacity increases with respect to temperature. The humidity of the air is also of benefit to the load capacity of SO2. When an adsorption process is interrupted and the activated carbon is kept closed for a while, the SO2 concentration at the exit of a fixed-bed adsorber is similar to that of the fresh activated carbon and begins at a very low value. It appears that the sorption potential has been refreshed after the storage period. Analysis of desorption experiments by simultaneous thermal analysis combined with mass spectrometry (MS) after loading, shows that the physisorbed SO2 and H2O are desorbed at low temperatures. At higher temperatures, the MS peak of SO2 and H2O occur at the same time. Compared with desorption immediately after loading, after one day, the desorption peak due to the physisorbed SO2 disappears. From this, it can be concluded that the refreshment of the loading capacity of the activated carbon after storage is mainly due to a change in the nature of the SO2 from a physisorbed state to a chemisorbed form. The same mechanism leads to a continuous refreshment of the sorption potential by means of a chemical reaction during the adsorption process. [source] Moisture adsorption by milk whey protein filmsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 3 2002C. M. P. Yoshida Edible films, using whey protein as the structural matrix, were tested for water vapour diffusion properties. Whey protein films were prepared by dispersing 6.5% whey protein concentrate (WPC) in distilled water with pH kept at 7.0. Glycerol was the plasticizer agent. Film slabs (13.5 × 3.5 cm) were put in a chamber at 25 °C and 75% relative humidity, being held in vertical planes for different periods of time. The mass gain was determined throughout the experiment. We show that moisture adsorption by milk whey protein films is well described by a linear diffusion equation model. After an adsorption experiment was performed the solution of the diffusion equation was fitted to the data to determine the diffusion coefficient of the material. [source] The effects of surface lactone hydrolysis and temperature on the specific and nonspecific interactions between phenobarbital and activated carbon surfacesJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 7 2006Dale Eric Wurster Abstract The effect of hydrolyzing lactone functional groups on the surfaces of different activated carbons upon the specific and nonspecific interactions between phenobarbital and activated carbon surfaces was studied. The effect of temperature on both specific and nonspecific interactions was also studied. The increase in OH groups on the surfaces of activated carbons, as a result of hydrolyzing surface lactone groups, caused an increase in the specific adsorption capacity (K2) for phenobarbital without having a significant effect on the hydrophobic bonding capacity (KHB). Increasing the temperature at which the adsorption experiment was carried out, on the other hand, resulted in a decrease in KHB without having a significant effect on K2. The decrease in KHB per unit temperature increase was the same regardless of the activated carbon. These results are in very good agreement with the modified-Langmuir-like equation (M-LLE). © 2006 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 95: 1540,1548, 2006 [source] Insulin transport across porous charged membranes: Effect of the electrostatic interactionBIOTECHNOLOGY PROGRESS, Issue 5 2009Shaoling Zhang Abstract Insulin transport phenomena across a series of porous charged membranes were studied at two pH conditions (pH 3.3 and pH 7.4) in this article. The membranes were prepared by pore-surface modification of porous poly(acrylonitrile) (PAN) membranes by grafting with weak acidic and basic functional groups. The insulin partition coefficient K between the membrane and solution was estimated from the equilibrium adsorption amount in the batch adsorption experiment. The insulin effective diffusion coefficient D inside the membrane was determined as a fitting parameter by matching the diffusion model with the experimental data of the diffusion measurement. Both K and D correlated well with the charge properties of the insulin and membrane: when the insulin and membrane carried opposite net charge, the partition coefficient showed relatively larger values, while the effective diffusion coefficient was reduced. The insulin permeability coefficient P obtained from the experimental results agreed with that estimated from the partition coefficient and effective diffusion coefficient. These results suggested that the combined effects of the solubility and diffusivity on the permeability coefficient complicated the relationship between the permeability and the charge properties of the insulin and membrane. Additionally, our calculation supported that insulin permeability was reduced by the boundary layer between the membrane and solution. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] Preparation and adsorption characteristic of polymeric microsphere with strong adsorbability for creatinineJOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY, Issue 3 2008Baojiao Gao Abstract Cross-linking terpolymer microspheres (HEMA/NVP/MBA; it can also be designated as HEMA/NVP because HEMA and NVP are main components) with an average diameter of 180 µm, were prepared via inverse suspension copolymerization by using 2-hydroxyethyl methacrylate (HEMA) and N -vinylpyrrolidone (NVP) as monomers and N,N,-methylene bisacrylamide (MBA) as cross-linked agent. The microsphere HEMA/NVP was chemically modified with 3,5-dinitrobenzoyl chloride (DNBC), and the functional microsphere DNBZ-HEMA/NVP, on which a great number of 3,5-dinitrobenzoate group (DNBZ) were bound, was obtained. The functional microsphere DNBZ-HEMA/NVP were characterized with FTIR and the chemical analysis method. The adsorption characteristics and mechanism of the absorption of DNBZ-HEMA/NVP for creatine was mainly studied. The results of static adsorption experiments show that the functional microsphere DNBZ-HEMA/NVP has very strong adsorption ability for creatinine, and the saturated adsorption amount is 25 mg/g. The adsorption capacity of the functional microsphere DNBZ-HEMA/NVP for creatinine is enhanced 20 times as against unmodified microsphere HEMA/NVP. The adsorption capacity is smaller, at lower and higher pH, and has a maximum as pH 8.5. The higher the salinity of the medium, the smaller the adsorption capacity. The adsorption capacity decreases with increasing temperature. The study results show that the adsorption of the microsphere DNBZ-HEMA/NVP for creatinine is ascribed to a chemical adsorption by driving of electrostatic interaction. © 2008 Wiley Periodicals, Inc. J Biochem Mol Toxicol 22:166,174, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20221 [source] The removal of reactive azo dyes by natural and modified zeolitesJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2003B Arma Abstract The adsorption mechanism of three reactive dyes by zeolite has been examined with the aim of identifying the ability of zeolite to remove textile dyes from aqueous solutions. Towards this aim, a series of batch adsorption experiments was carried out, along with determination of the electrokinetic properties of both natural and modified zeolites. The adsorbent in this study is a clinoptilolite from the Gördes region of Turkey. The reactive dyes CI Reactive Black 5, Red 239 and Yellow 176 are typical azo dyes extensively used in textile dyeing. Adsorption tests were carried out as a function of mixing time, solids concentration, dye concentration and pH. The adsorption results indicate that the natural zeolite has a limited adsorption capacity for reactive dyes but is substantially improved upon modifying its surfaces with quaternary amines. An electrostatic adsorption mechanism involving the formation of a bilayer of amine molecules on the clinoptilolite surface onto which anionic dye molecules adsorb, depending on their polarities, is proposed. The results are also supported by electrokinetic measurements. The adsorption data were fitted to the Langmuir isotherm and it was found that the modified sepiolite yields adsorption capacities (qe) of 111, 89 and 61 mg g,1 for Red, Yellow and Black, respectively. These results are comparable to a popular adsorbent, activated carbon. Copyright © 2003 Society of Chemical Industry [source] Adsorption separation of terpene lactones from Ginkgo biloba L. extract using glass fiber membranes modified with octadecyltrichlorosilaneJOURNAL OF SEPARATION SCIENCE, JSS, Issue 11 2005I-Fang Su Abstract In this study porous glass fiber membranes were modified by reaction with octadecyltrichlorosilane to form C18 hydrophobic membranes. The contact angle and the CH2 vibration bands at 2855 and 2920 cm,1 found by FTIR measurements verified the successful immobilization of C18 groups on the glass fiber membranes. The resulting C18 hydrophobic membranes were used to adsorb terpene lactones from crude Ginkgo biloba L. extracts. In batch adsorption processes, the modified C18 membranes exhibited a better adsorption performance than commercial C18 solid phase extraction adsorbents. Different desorption solvents were tested and ethyl acetate was found to preferentially desorb terpene lactones from the modified C18 membranes. In flow adsorption experiments at 1 mL/min, terpene lactone contents higher than 6 wt% (the standardized content) could be achieved in the elution step using ethyl acetate. [source] Equilibrium and kinetic study for the removal of malachite green using activated carbon prepared from Borassus flabellofer male flowerASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2010P. E. Jagadeesh Babu Abstract Activated carbon was prepared from dried Borassus flabellofer male flower and batch adsorption experiments were conducted to study its potential to remove malachite green (MG) dye. The process was further optimized by studying the operating variables like initial pH of the stock solution, activation temperature, initial dye concentration, adsorbent loading and contact time. The optimized pH and activation temperatures were found to be 7.55 and 450 °C respectively, where further analysis was made using these optimal variables. Linear, Freundlich and Langmuir isotherms were studied and it was found that the Langmuir isotherms have the highest correlation coefficients compared to the others. Further, the sorption kinetics were analysed using pseudo-first-order and pseudo-second-order kinetic models. The data showed that the second-order equation was the more appropriate, which indicate that the intra-particle diffusion is the rate limiting factor. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Adsorption properties of microwave synthesized inorgano,organo montmorilloniteASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 2 2010Miray Emreol Abstract The aim of this study is to determine the adsorption properties of microwave synthesized inorgano,organo montmorillonites. Microwave irradiation is preferred because of its low time and energy consumption properties, forming an advantage in industrial applications. In addition to the intercalation of Keggin and hexadecyltrimethylammonium (HDTMA+) cations, the aging process of pillaring solution was also carried out through the microwave irradiation. Both inorgano clays, namely the parents, and their inorgano,organo derivatives, were prepared by using the same amounts of aluminum by keeping the OH,/Al3+ and Al3+/clay ratios constant. The HDTMA+/clay ratio was changed in inorgano-organo clays (IOCs) during the preparation. The effects of these parameters on the surface properties and adsorption behaviors of the samples were investigated by conducting X-ray diffraction (XRD), Fourier transform infrared (FTIR) and simultaneous thermal analyses (STA), as well as batch adsorption experiments, in which phenol was used as a model pollutant. The results of XRD analyses reveal that the intercalation is successfully achieved. The existence of the Keggin and HDTMA+ cations was observed in FTIR spectra of the samples. Through the STA, it was determined that the existence of organic layer increases the dehydroxylation temperature and the thermal behavior of inorgano-organo montmorillonites strongly depends on the structure of the parent clay. An increase in the adsorption efficiencies with increasing HDTMA+/clay ratio was observed, except with the highest ratio. The behavior of this sample was explained by the formation of the second HDTMA+ layer leading to the hydrophilic surface formation. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Insulin adsorption into porous charged membranes: Effect of the electrostatic interactionBIOTECHNOLOGY PROGRESS, Issue 4 2009Shaoling Zhang Abstract Insulin adsorption into a series of porous charged membranes was investigated by batch adsorption experiments, and the experimental results were analyzed by the homogeneous diffusion model. The membranes used in this study were prepared by pore-surface modification of porous poly(acrylonitrile) (PAN) membranes by grafting with weak acidic and basic functional groups. The amount of insulin adsorbed into the membrane was determined from the material balance of insulin. The insulin partition coefficient K between the membrane and solution was estimated from the equilibrium adsorption amount, and the effective diffusion coefficient D was estimated by matching the model with the experimental data as a fitting parameter. The dependence of K and D on the charge properties of the insulin and membrane is observed and discussed. The partition coefficient K increased when the insulin and the membrane carried opposite charges, on the other hand, the effective diffusion coefficient D was reduced. These results indicate that the electrostatic interaction between the insulin and the membranes played an important role in the insulin adsorption. © 2009 American Institute of Chemical Engineers Biotechnol. Prog. 2009 [source] | ||||||||||