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1.
Dynamic adsorption behavior between Cu2+ ion and water‐insoluble amphoteric starch was investigated. The sorption process occurs in two stages: external mass transport occurs in the early stage and intraparticle diffusion occurs in the long‐term stage. The diffusion rate of Cu2+ ion in both stages is concentration dependent. In the external mass‐transport process, the diffusion coefficient (D1) increases with increasing initial concentration in the low‐ (1 × 10?3‐4 × 10?3M) and high‐concentration regions (6 × 10?3‐10 × 10?3M). The values of adsorption activation energy (kd1) in the low‐ and high‐concentration regions are 15.46–24.67 and ?1.80 to ?11.57 kJ/mol, respectively. In the intraparticle diffusion process, the diffusion coefficient (D2) increases with increasing initial concentration in the low‐concentration region (1 × 10?3‐2 × 10?3M) and decreases with increasing initial concentration in the high‐concentration region (4 × 10?3‐10 × 10?3M). The kd2 values in the low‐ and high‐concentration regions are 9.96–15.30 and ?15.53 to ?10.71 kJ/mol, respectively. These results indicate that the diffusion process is endothermic in the low‐concentration region and is exothermic in the high‐concentration region for both stages. The external mass‐transport process is more concentration dependent than the intraparticle diffusion process in the high‐concentration region, and the dependence of concentration for both processes is about equal in the low‐concentration region. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2849–2855, 2001 相似文献
2.
P. SenthilKumar S. Ramalingam R. V. Abhinaya S. Dinesh Kirupha T. Vidhyadevi S. Sivanesan 《加拿大化工杂志》2012,90(4):973-982
Cashew nut shell (CNS) is an agricultural waste was investigated as a new adsorbent for the removal of zinc(II) from aqueous environment. Effects of solution pH, CNS dose, contact time, initial zinc(II) concentration and temperature on removal efficiency were tested and optimum conditions were evaluated. The equilibrium data were fitted well with Langmuir isotherm model and pseudo‐second‐order kinetic model. Langmuir monolayer adsorption capacity of CNS was examined as 24.98 mg/g. Changes in standard Gibbs free energy (?G°), standard enthalpy (?H°) and standard entropy (?S°) showed that the sorption of zinc(II) ions onto CNS are spontaneous and exothermic at 303–333 K. Sorption process was found to be controlled by both surface and pore diffusion. A batch adsorber was designed for different CNS dose to effluent volume ratios using Langmuir equation. Effective diffusivity values were found to be 1.927 × 10?11 (10 mg/L), 2.135 × 10?11 (20 mg/L), 2.267 × 10?11 (30 mg/L), 2.305 × 10?11 (40 mg/L) and 2.362 × 10?11 (50 mg/L) m2/s. © 2011 Canadian Society for Chemical Engineering 相似文献
3.
This work is focused on the removal of Ni(II) from aqueous solutions by sorption onto newly developed magnetite‐loaded calcium alginate particles. The uptake of Ni(II) by these magnetite particles, with their mean geometrical diameter 84 and 508 μm, is best described by the Freundlich isotherm and the constants KF and 1/n were found to be 3.491 mg g?1, 0.731 and 0.793 mg g?1 and 0.907, respectively. The mean sorption energy, as determined by Dubinin‐Radushkevich isotherm for 508‐ and 84‐μm sized particles was evaluated to be 8.9 and 8.0 kJ mol?1, respectively, thus, suggesting the ion‐exchange mechanism for uptake process. Of the various kinetic models proposed, the kinetic Ni(II)‐uptake data were best interpreted by “Simple Elovich” and “Power function” as suggested by their higher regression values. The almost linear nature of plots of log(% sorption) versus log(time) was indicative of intraparticle diffusion. The values of intraparticle diffusion coefficients Kid were found to be 63.49 × 10?2 and 94.35 × 10?2 mg l?1 min0.5. The intraparticle diffusion was also confirmed by Bangham equation. Finally, various thermodynamic parameters were evaluated. The negative ΔG° indicated spontaneous nature of uptake process while positive ΔH° value suggested exothermic nature of the sorption process. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
4.
This work was focused on the removal of phosphate ions using polypyrrole‐coated sawdust as a novel cost‐effective sorbent. The phosphate uptake followed the Langmuir sorption isotherm, and the sorption capacity at 20, 35, and 50°C was found to be 17.33, 23.41, and 30.39 mg/g, respectively; this indicated favorable sorption at higher temperatures. The kinetic uptake data were modeled with the Lagergren equation, first‐order and second‐order kinetic models, and the simple Elovich model. The results indicated that the Lagergren model best described the uptake data. The intraparticle diffusion coefficient, as determined for 250–211‐ and 630–600‐μm sorbent particles at 20°C, was found to be 287.3 × 10?2 and 228.3 × 10?2 mg g?1 min?1, respectively. The intraparticle diffusion was also confirmed with the Bangham equation. The sorption mean free energy, calculated with the Dubinin–Radushkevich equation, was found to be 10.98 kJ/mol, thus confirming an ion‐exchange regulated sorption process. The positive value of the enthalpy change (i.e., 4.23 kJ/mol) confirmed the endothermic nature of the sorption process. The negative values of the change in the standard free energy were indicative of the spontaneous nature of the sorption process. Finally, the activation energy of the sorption process for 250–212‐μm particles, determined with the Arrhenius equation, was found to be 41.68 J/mol. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
5.
A. M. Al-Damkhi R. S. Al-Ameeri G. V. Jeffreys C. J. Mumford 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1987,37(4):215-228
A study has been made of the vapour-phase adsorptive separation of n-alkanes from Kuwait kerosene using zeolite molecular sieves (LMS-5A). The object was to identify the optimum operating conditions, in terms of flow rate, adsorption temperature and zeolite particle size for the separation of n-alkanes from kerosene, so that the remaining stock would also be of marketable quality. The effect of these conditions on the height of the mass transfer zone (HMTZ) and the dynamic capacity (Ad) of zeolite was also investigated. The adsorptive separation process comprised one cycle of adsorption using a fixed bed of zeolite type-5A. The bed was fed with kerosene vapour until equilibrium had been achieved, whereby the n-paraffins were adsorbed and the denormalized material excluded. The processes were carried out isobarically at one atmosphere. The optimum operating conditions were found to be a feed flow rate of 33.33 × 10?9 m3 s?1, an adsorption temperature of 643 K and a zeolite pellet fraction size of 1.0–2.0 × 10?3m. This yielded an HMTZ value of 0.206 m and an Ad of 9.653 × 10?2 kg n-paraffins kg?1 zeolite. The data will serve as a basis for the design of commercial plant. 相似文献
6.
Jiansheng Fan Wenbin Qian Xiqun Zhou Chen Qian Xiaohong Jin Lili Wang Jianxin Bai Hanjie Ying 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2012,87(7):924-931
BACKGROUND: Owing to the rapid depletion of petroleum fuel, the production of bio‐butanol has attracted much attention. However, low butanol productivity severely limits its potential industrial application. It is important to establish an approach for recovering low‐concentration butanol from fermentation broth. Experiments were conducted using batch adsorption mode under different conditions of initial butanol concentration and temperature. Batch adsorption data were fitted to Langmuir and Freundlich isotherms and the macropore diffusion, pseudo‐first‐ and second‐order models for kinetic study. RESULTS: The maximum adsorption capacity of butanol onto KA‐I resin increase with increasing temperature, ranged from 139.836 to 304.397 mg g?1. The equilibrium adsorption data were well fitted by the Langmuir isotherm. The adsorption kinetics was more accurately represented by the macropore diffusion model, which also clearly predicted the intraparticle distribution of the concentration. The effective pore diffusivity (Dp) was dependent upon temperature, but independent of initial butanol concentration, and was 0.251 × 10?10, 0.73 × 10?10, 1.32 × 10?10 and 4.31 × 10?10 m2 s?1 at 283.13, 293.13, 303.13 and 310.13 K, respectively. CONCLUSION: This work demonstrates that KA‐I resin is an efficient adsorbent for the removal of butanol from aqueous solutions and available for practical applications for future in situ product recovery of butanol from ABE fermentation broth. Copyright © 2012 Society of Chemical Industry 相似文献
7.
Changhua Liu Xun Dai Jianguang Chen Yanqing Chen Xiaoli Guo Yuming Huang 《应用聚合物科学杂志》2009,113(4):2339-2345
The grafting of 4‐vinyl pyridine (4‐VP) onto konjac glucomannan (KGM) by ammonium persulfate (APS) as the initiator was studied in an acid aqueous solution under an inert atmosphere. The grafting ratio (G%) and grafting efficiency (E%) were evaluated comparatively. The dependence of these parameters on the initiator concentration, sulfuric acid concentration, ratio of monomer to KGM, temperature, and reaction time was also investigated. Under conditions of [KGM] = 1.00 g/L, [APS] = 1.00 × 10?2 mol/L, [4‐VP] = 9.32 × 10?2 mol/L, [H+] = 5.00 × 10?2 mol/L, temperature = 35°C, and time = 120 min, the optimum G% and E% were 307.27 and 52.75%, respectively. The proof of grafting was obtained from thermogravimetric analysis and infrared spectra. Preliminary research of the graft's adsorption capacity for heavy‐metal ions [Cr(VI), Cu(II), Pb(II), and Cd(II)] was done. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
8.
Modeling multicomponent adsorption of monoclonal antibody charge variants in cation exchange columns
Yinying Tao Nianyun Chen Giorgio Carta Gisela Ferreira David Robbins 《American Institute of Chemical Engineers》2012,58(8):2503-2511
Transport models are developed for the adsorption of monoclonal antibody charge variants in cation exchange columns for two different matrices: UNOsphere S, which has a macroporous architecture, and Capto S, which contains charged dextran polymers grafted to an agarose matrix. The UNOsphere S protein adsorption kinetics is described by a macropore diffusion model with effective pore diffusivity De = 8.3 × 10?8 cm2/s, which successfully predicts resolution of charge variants by frontal analysis at residence times, L/u, between 0.9 and 5.4 min. The Capto S adsorption kinetics is very fast for individual charge variants and for coadsorption of their mixtures, but is dramatically slower for sequential adsorption, when a more strongly bound variant displaces a more weakly bound one. A Maxwell‐Stefan model assuming single‐file diffusion predicts, in agreement with experiments, poor resolution of charge variants by frontal analysis even at long residence times as a result of highly hindered counterdiffusion. © 2011 American Institute of Chemical Engineers AIChE J, 58: 2503–2511, 2012 相似文献
9.
S. Borthakur R. C. Srivastava 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1991,51(4):497-506
The removal of p-toluene sulphonic acid (p-TSA) from concentrated solution by granular activated carbon (GAC) was studied in batch experiments. The first order rate constant was found to be 5.5010 × 10?5 s?1 for a solution of 1000 mg dm?3. In order to establish the rate limiting step the pore and film diffusion coefficients were calculated from the half time equations. Film diffusion was found to be rate limiting. The average value of the external mass transport rate constant was 2.91 × 10?6 cm s?1. The adsorption isotherm was adequately described by the Langmuir model and belongs to type ‘H’ of Giles' classification. 相似文献
10.
Hong Yu Yang Xiu Mei Zhang Li Jie Duan Ming Yao Zhang Guang Hui Gao Hui Xuan Zhang 《Journal of Polymer Research》2012,19(9):1-7
An innovative spherical poly(vinyl alcohol)(PVA)/peat/clay porous composite bead was prepared and shown to be suitable for use as an adsorbent. The mass transport process for the adsorption of metal ions onto this composite bead in an aqueous system was investigated. In the external mass transport process, the diffusion coefficient (D1) of Cu+2 and Zn+2 ions increased with increasing initial metal ion concentration and the increasing effect was more pronounced in the initial metal ion concentrations range of 18?×?10-3 to 22?×?10-3?M. The diffusion rate of Zn+2 ions was faster than that of Cu+2 ions. In the intraparticle diffusion process, the diffusion coefficient (D2) decreased with increasing initial metal ion concentration in the initial concentration range of 1?×?10-3 to 4?×?10-3?M, and the value of D2 maintained an almost constant value in the initial concentration range of 8?×?10-3 to 22?×?10-3?M. The rate of ion diffusion within the adsorbent for Cu+2 ions was faster than that for Zn+2 ions. The adsorption mechanism was controlled by the intraparticle diffusion process. The adsorption followed the Langmuir adsorption isotherm model. The maximum amount of adsorbed metal ions for Cu+2 and Zn+2 ions were 22.57 and 13.62?mg/g composite bead, respectively. 相似文献
11.
This study describes dynamic uptake of antibiotic drug diclofenac sodium from aqueous solution using polyaniline as sorbent. The sorbent polyaniline was prepared by oxidative polymerization of aniline and characterized by FTIR spectrum analysis and TGA. The optimum sorbent/sorbate mg/mL ratio and pH range for maximum drug uptake have been found to be 2.0 and 5.5 to 10.5, respectively. Out of various kinetic models applied, the pseudo second‐order kinetic equation has been found to fit well on the kinetic uptake data. The pseudo second‐order rate constants for adsorption have been found to be 0.982 × 10?2, 7.24 × 10?2, and 18.09 × 10?2 min?1 mg?1 g for drug solutions with initial concentrations of 10, 20, and 30 mg L?1, respectively. The overall sorption process has been found to be governed by intraparticle diffusion.The sorptive removal of drug from aqueous solution has also resulted in enhancement in bacterial growth of Escherichia coli. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
12.
《分离科学与技术》2012,47(8):1793-1807
Abstract In the present work, a study of the kinetics of adsorption of Cs+, Co2+, and Sr2+ on four hydrous titanium oxides, prepared in different media, and designated as Ti‐I, Ti‐II, Ti‐III, and Ti‐IV, was carried out. In the aqueous medium, the internal diffusion coefficients, Di for Cs+ were found to be equal to 3.7×10?9, 3.7×10?9, 2.3×10?9, and 1.5?10?9 cm2/s, in Ti‐I, Ti‐II, Ti‐III, and Ti‐IV, respectively. For Co2+ and Sr2+, these values are equal to 0.96×10?9 and 0.64×10?9 cm2/s, respectively for Ti‐IV. In Ti‐IV, Di for all ions generally increases on adding methanol or propanol. This is probably due to greater dehydration, leading to faster ion diffusion, and, hence, to a decrease of ion mobility due to stronger interaction with the surface. In all media in Ti‐IV, the order: Di(Cs+)>Di(Co2+)≥Di(Sr2+) was found which is due to a stronger interaction of the bivalent ions with the exchange sites. 相似文献
13.
Metal‐chelating properties of poly(2‐hydroxyethyl methacrylate–methacryloylamidohistidine) membranes
Metal‐chelating membranes have advantages as adsorbents in comparison with conventional beads because they are not compressible and they eliminate internal diffusion limitations. The aim of this study was to explore in detail the performance of poly(2‐hydroxyethyl methacrylate–methacryloylamidohistidine) [poly(HEMA–MAH)] membranes for the removal of three toxic heavy‐metal ions—Cd(II), Pb(II), and Hg(II)—from aquatic systems. The poly(HEMA–MAH) membranes were characterized with scanning electron microscopy and 1H‐NMR spectroscopy. The adsorption capacity of the poly(HEMA–MAH) membranes for the selected heavy‐metal ions from aqueous media containing different amounts of these ions (30–500 mg/L) and at different pH values (3.0–7.0) was investigated. The adsorption capacity of the membranes increased with time during the first 60 min and then leveled off toward the equilibrium adsorption. The maximum amounts of the heavy‐metal ions adsorbed were 8.2, 31.5, and 23.2 mg/g for Cd(II), Pb(II), and Hg(II), respectively. The competitive adsorption of the metal ions was also studied. When the metal ions competed, the adsorbed amounts were 2.9 mg of Cd(II)/g, 14.8 mg of Pb(II)/g, and 9.4 mg of Hg(II)/g. The poly(HEMA–MAH) membranes could be regenerated via washing with a solution of nitric acid (0.01M). The desorption ratio was as high as 97%. These membranes were suitable for repeated use for more than three adsorption/desorption cycles with negligible loss in the adsorption capacity. The stability constants for the metal‐ion/2‐methacryloylamidohistidine complexes were calculated to be 3.47 × 106, 7.75 × 107, and 2.01 × 107 L/mol for Cd(II), Pb(II), and Hg(II) ions, respectively, with the Ruzic method. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1213–1219, 2005 相似文献
14.
Uranyl ion adsorption from aqueous solutions has been investigated by chemically cross-linked polyelectrolyte acrylamide/maleic acid (CAMA) hydrogels. CAMA hydrogels with various compositions were prepared from ternary mixtures of acrylamide (A), maleic acid (MA), and water by free radical polymerization in aqueous solution using multifunctional cross-linkers such as ethylene glycol dimethacrylate (EGDMA) and 1,4-butanediol dimethacrylate (BDMA). Uranyl ion adsorption from aqueous solutions was studied by batch sorption technique at 25°C. The effect of uranyl ion concentration and mass of adsorbent on the uranyl ion adsorption were examined. In the experiments of the sorption, L type sorption in the Giles classification system was found. Some binding parameters such as initial binding constant (K i ), equilibrium constant (K), monolayer coverage (n), site-size (u), and maximum fractional occupancy (Ô) for CAMA hydrogel-uranyl ion binding system were calculated by using Langmuir linearization method. Finally, the amount of sorbed uranyl ion per gram of dry hydrogel (q) was calculated to be 3.29 × 10?4 ? 15.87 × 10?4 mol uranyl ion per gram for CAMA hydrogels. Adsorption of uranyl ion was changed range 8.17–48.10%. 相似文献
15.
Pervaporation separation of ethanol/water mixture using modified zeolite filled PDMS membranes
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In this article, the composite polydimethylsiloxane (PDMS) membranes supported by cellulose acetate (CA) microfiltration membrane were successfully prepared by adding modified zeolite particles with a silane coupling agent, NH3–C3H6–Si(OC2H5)3. The sorption and diffusion behaviors of ethanol and water in the films were studied. The results showed that with the increase in the modified zeolite content, the solubility selectivity increased, but the diffusion selectivity first increased, then decreased. The effects of modified zeolite content and feed temperature on the pervaporation performance of the composite membranes in 10 wt % ethanol/water mixture were also investigated. When modified zeolite loading was 20 wt %, for 10 wt % ethanol/water mixture at 40°C, the permeate flux was 348.7 g·m?2·h?1, the separation factor was 14.1, and the permeate separate index was 4568, respectively. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41897. 相似文献
16.
Zhongwei Zhao Jing Liu Wentang Xia Caifang Cao Xingyu Chen Honggui Li 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2010,85(1):121-126
BACKGROUND: Mo is a harmful element that should strictly be limited in electrolytic manganese dioxide but can readily be removed by Mn3O4. However, as its adsorption mechanism is not yet clear the aims of this work are to clarify the absorption phenomena and specific reaction processes of Mo onto Mn3O4. RESULTS: Some theoretical parameters have been obtained: the total surface site density and protonation constants (NT = 6.84 × 10?3 mol g?1, , ) were obtained by non‐linear data fitting of acid‐base titrations. Distribution of soluble Mo species derived from thermodynamic calculations showed that the concentration of poly‐molybdenum acid ion was extraordinarily low and could be ignored when the concentration of soluble Mo was 1 mg L?1. The adsorption isotherm followed the Freundlich adsorption equation. Under the conditions V = 0.15 L, W = 2 g L?1, [Mo]T = 1.12 mg L?1, T = 80 °C, P = 1.013 × 105 Pa, 1.0 mol L?1 MnSO4 and pH range 1–6.5, the non‐electrostatic model (NEM) was used to quantify Mo adsorption. CONCLUSION: The surface adsorption complexation modeling of Mo onto Mn3O4 can be successfully applied to predict adsorption rates of Mo onto Mn3O4 at different pH values, with an absolute error less than 6%. Copyright © 2009 Society of Chemical Industry 相似文献
17.
Yi Liu Yuru Kang Dajian Huang Aiqin Wang 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2012,87(7):1010-1016
BACKGROUND: The adsorption of Cu2+ from aqueous solution using crosslinked chitosan hydrogels impregnated with Congo Red (CR) by ion‐imprint technology was systematically investigated with particular reference to the effects of contact time, pH, and initial concentration on adsorption. RESULTS: The adsorption capacity of the crosslinked chitosan without impregnation was only 68.68 mg g?1 for Cu2+. However, the adsorption capacity increased from 77.42 (without imprint ion) to 84.54 mg g?1 (imprint ion content 0.5 mmol) after the chitosan was impregnated with a ratio of 1/12 of CR to chitosan. The as‐prepared adsorbents were found to be pH‐dependent and the process of adsorption agreed well with the Freundlich isotherm. The loaded adsorbents could be regenerated and reused without the appreciable loss of capacity. CONCLUSION: Chitosan hydrogels impregnated with CR showed higher Cu2+ adsorption capacities compared with those prepared conventionally without imprint ion, and thus developed a good approach to increase Cu2+ adsorption efficiency in the treatment of waste‐water. Copyright © 2012 Society of Chemical Industry 相似文献
18.
M. Pérez‐Tello F. Rodríguez‐Felix M. M. Castillo‐Ortega V. M. Sánchez‐Corrales 《应用聚合物科学杂志》2012,124(2):1695-1706
A model for the adsorption of gold from I2/I? aqueous solutions onto a cellulose acetate (CA)‐polyaniline (PANI) porous membrane is presented. The adsorption of gold is represented by an ion‐exchange overall reaction in which AuI2? ions replace the Cl? ions at the active sites of the polyaniline matrix. The model incorporates the external mass transfer of AuI2? from the bulk solution to the membrane surface, followed by the pore diffusion of AuI2? to reach the active sites in the membrane. The overall ion‐exchange reaction was assumed to achieve local instantaneous equilibrium. Verification of the kinetic model with the experimental data showed that the effective diffusivity of AuI2? within the membrane is about 8.3 × 10?6 cm2/s. The potential applications of the present formulation are discussed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
19.
Arjumand A. Kittur Mahadevappa Y. Kariduraganavar Srikant S. Kulkarni Mrityunjaya I. Aralaguppi 《应用聚合物科学杂志》2005,96(4):1377-1387
ZSM‐5 zeolite‐incorporated poly(dimethyl siloxane) membranes were prepared, and the molecular dispersion of the zeolite in the membrane matrix was confirmed with scanning electron microscopy. After the swelling of the membranes was studied at 30°C, the membranes were subjected to the pervaporation separation of isopropyl alcohol/water mixtures at 30, 40, and 50°C. The effects of the zeolite loading and feed composition on the pervaporation performances of the membranes were analyzed. Both the permeation flux and selectivity increased simultaneously with increasing zeolite content in the membrane matrix. This was examined on the basis of the enhancement of hydrophobicity, selective adsorption, and the establishment of molecular sieving action. The membrane containing the highest zeolite loading (30 mass %) had the highest separation selectivity (80.84) and flux (6.78 × 10?2 kg m?2 h?1) at 30°C with 5 mass % isopropyl alcohol in the feed. From the temperature dependence of the diffusion and permeation values, the Arrhenius activation parameters were estimated. A pure membrane exhibited higher activation energy values for permeability (Ep) and diffusivity (ED) than zeolite‐incorporated membranes, and signified that permeation and diffusion required more energy for transport through the pure membrane because of its dense nature. Obviously, the zeolite‐incorporated membranes required less energy because of their molecular sieving action, which was attributed to the presence of straight and sinusoidal channels in the framework of the zeolite. For the zeolite‐incorporated membranes, the activation energy values obtained for isopropyl alcohol permeation were significantly lower than the water permeation values, and this suggested that the zeolite‐incorporated membranes had higher selectivity toward isopropyl alcohol. The Ep and ED values ranged between 21.81 and 31.12 kJ/mol and between 15.27 and 41.49 kJ/mol, respectively. All the zeolite‐incorporated membranes exhibited positive values of the heat of sorption, and this suggested that the heat of sorption was dominated by Henry's mode of sorption. sorption. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1377–1387, 2005 相似文献
20.
Behaviors of Chemically Crosslinked CAAMPS Hydrogels in Uptake of Uranyl Ions from Aqueous Solutions
Uranyl ion adsorption from aqueous solutions has been investigated by chemically crosslinked (C) polyelectrolyte acrylamide/2-acrylamido-2-methyl-1-propanesulfonic acid (CAAMPS) hydrogels. CAAMPS hydrogels with various compositions were prepared from ternary mixtures of acrylamide (A), 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS), and water by free radical polymerization in an aqueous solution using multifunctional crosslinkers such as ethylene glycol dimethacrylate (EGDMA) and 1,4 butanediol dimethacrylate (BDMA). The swelling equilibrium of polyelectrolyte copolymer gels containing of CAAMPS hydrogels has been studied as a function of copolymer composition. Swelling experiments were performed in water at 25°C, gravimetrically. The influence of AMPS content in hydrogels was examined. The weight-swelling ratio of CAAMPS hydrogels was increased up to 127.03 (for 300 mg AMPS and crosslinked by EGDMA) and 93.32 (for 300 mg AMPS and crosslinked by BDMA), while acrylamide hydrogels swelled up to 10.27 (crosslinked by EGDMA) and 10.06 (crosslinked by BDMA). Uranyl ion adsorption from aqueous solutions was studied by batch sorption technique at 25°C. The effect of uranyl ion concentration and mass of AMPS on the uranyl ion adsorption were examined. In the experiments of the sorption, L type sorption in the Giles classification system was found. Finally, the amount of sorbed uranyl ion per gram of dry hydrogel (q) was calculated to be 0.67 × 10?3–2.11 × 10?3 mol uranyl ion per gram for CAAMPS hydrogels. Removal effiency of uranyl ions (RE%) was changed range 9.05–29.92%. The values of partition ratio, (K d ) of uranyl ions was calculated to be 0.10–0.43 for CAAMPS hydrogels. 相似文献