Dowex50W-X树脂吸附硫酸溶液中的锶

In this study,strontium adsorption from sulfuric acid solution by different Dowex 50W-X ion exchange resins was investigated.Among these resins,Dowex 50W-X8 resin showed the maximum sorption of strontium from the aqueous solutions.The effect of pH,contact time,mass of resin,temperature,and concentration of interfering ions on strontium adsorption were evaluated to determine the optimum conditions of strontium sorption process.The kinetic models of sorption were analyzed using pseudo-first and pseudo-second order models.The results indicated that the pseudo-second order kinetic model was more appropriate than the other one.Moreover,the data obtained in this study were fitted into several sorption isotherm models and it was found that the Langmuir sorption isotherm shows the best fitting to the experimental data.     

Removal of zinc ions from aqueous solution using a cation exchange resin

The present study is concerned with the mass transfer and kinetics study of zinc ions removal from aqueous solution using a cation exchange resin packed in a rotating cylindrical basket reactor. The effect of various experimental parameters on the rate of zinc ion removal, such as initial zinc ion concentration, packed bed rotation speed and temperature has been investigated. In addition to find a suitable equilibrium isotherm and kinetic model for the zinc ion removal in a batch reactor. The experimental isotherm data were analyzed using the Langmuir, Freundlich and D–R equations. The equilibrium data fit well in the Langmuir isotherm. The experimental data were analyzed using four sorption kinetic models, pseudo-first and second-order equations, the Elovich and the intraparticle diffusion model equation, to determine the best fit equation for the biosorption of zinc ions onto purolite C-100 MH resin. Results show that the Elovich equation provides the best correlation for the biosorption process.     

Removal of copper ions from aqueous solution by adsorption using LABORATORIES-modified bentonite (organo-bentonite)

Equilibrium, kinetic and thermodynamic aspects of the adsorption of copper ions from an aqueous solution using linear alkylbenzene sulfonate (LABORATORIES) modified bentonite (organo-bentonite) are reported. Modification of bentonite was performed via microwave heating with a concentration of LABORATORIES surfactant equivalent to 1.5 times that of the cation exchange capacity (CEC) of the raw bentonite. Experimental parameters affecting the adsorption process such as pH, contact time and temperature were studied. Several adsorption equations (e.g., Langmuir, Freundlich, Sips and Toth) with temperature dependency were used to correlate the equilibrium data. These models were evaluated based on the theoretical justifications of each isotherm parameter. The Sips model had the best fit for the adsorption of copper ions onto organo-bentonite. For the kinetic data, the pseudo-second order model was superior to the pseudo-first order model. Thermodynamically, the adsorption of copper ions occurs via chemisorption and the process is endothermic (ΔH⁰>0), irreversible (ΔS⁰>0) and nonspontaneous (ΔG⁰>0).     

油页岩灰渣合成Na-A沸石用于去除水溶液中Cu2+（英文）

Na-A zeolite was synthesized using oil shale ash （OSA）, which is a solid by-product of oil shale proc- essing. The samples were characterized by various techniques, such as scanning electron microscopy, X-ray diffrac- tion and Brunaner Emmet Teller method. The batch isothermal equilibrium adsorption experiments were performed to evaluate the ability of Na-A zeolite for removal of Cu （II） from aqueous solutions. The effects of operating pa- rameters, such as concentration of copper solutions, adsorbent dosages, pH value of solutions and temperature, on the adsorption efficiency were investigated. The equilibrium adsorption data were fitted with Langmuir and Freundlich models. The maximum adsorption capacity of Na-A zeolite obtained from the Langmuir adsorption iso- therm is 156.7 mg.g-t of Cu （lI）. The increase of pH level in the adsorption process suggests that the uptake of heavy metals on the zeolite follows an ion exchange mechanism. The batch kinetic data fit the pseudo-second order equation well. The thermodynamic parameters, such as changes in Gibbs free energy （AG）, enthalpy （AH） and en- tropy （AS）, are used to predict the nature of the adsorption process. The negative AG values at different tempera- tures confirm that the adsorption processes are spontaneous.     

Batch adsorptive removal of copper ions in aqueous solutions by ion exchange resins: 1200H and IRN97H

The removal of copper from aqueous solution by ion exchange resins, such as 1200H and IRN97H, is described. Effect of initial metal ion concentration, agitation time and pH on adsorption capacities of ion exchange resins was investigated in a batch mode. The adsorption process, which is pH dependent, shows maximum removal of copper in the pH range 2–7 for an initial copper concentration of 10 mg/L. The experimental data have been analyzed by using the Freundlich, Langmuir, Redlich-Peterson, Temkin and Dubinin-Radushkevich isotherm models. The batch sorption kinetics have been tested for a first-order, pseudo-first order and pseudo-second order kinetic reaction models. The rate constants of adsorption for all these kinetic models have been calculated. Results showed that the intraparticle diffusion and initial sorption into resins of Cu(II) in the ion exchange resins was the main rate limiting step. The uptake of copper by the ion exchange resins was reversible and thus has good potential for the removal/recovery of copper from aqueous solutions. We conclude that such ion exchange resins can be used for the efficient removal of copper from water and wastewater. This paper is dedicated to Professor Hyun-Ku Rhee on the occasion of his retirement from Seoul National University.     

Aqueous Phase Adsorption of Cephalexin onto Bentonite and Activated Carbon

The adsorption of cephalexin in aqueous solution has been investigated using bentonite and activated carbon as the adsorbents. Batch kinetics and isotherm studies were carried out to evaluate the effect of contact time, adsorbent dosage, pH, particle size, and temperature. Adsorption equilibrium data were well represented by the Langmuir and Freundlich isotherm models. The adsorption intensity was found to be increased as the aqueous phase pH increased, and had a maximum at pH = 6.1. The pseudo-first order, pseudo-second order, and intraparticle diffusion kinetic models were used to describe the kinetic data. The experimental data fitted very well with the pseudo-second-order kinetic model and also followed the simple external and intraparticle model.     

Removal of nickel from effluents by chelating ion exchange

BACKGROUND: Nickel is a highly toxic metal which is discharged into receiving waters by several industries, in particular, electroplating, PCB and electronics manufacturers. In the present study, a new ion exchanger has been assessed for its ability to remove nickel from solution. RESULTS: By comparing the SSE of different models in the nickel metal ion system, it seems that Redlich‐Peterson isotherm was the best fit model for the three metal ions. But the Langmuir was of a very similar magnitude. The equilibrium sorption capacity has been determined as 2.18 mmol/g and the batch contact time studies have been analyzed and compared using three kinetic models. The rate data were best correlated using the Elovich kinetic model. CONCLUSION: The batch sorption system is a well developed system for the application in the field of water pollution collected in small scale plants. The suitability of a sorbent is determined by the cost, sorption performance and regeneration efficiency. The sorption capacity of resin for nickel metal ions was determined as 2.18 mmol/g. In order to develop a treatment system design it is also important to determine the best kinetic model, Elovich kinetic model, to describe the rate of nickel removal. Copyright © 2008 Society of Chemical Industry     

Application of Aqai Stalks as Biosorbents for the Removal of the Dye Procion Blue MX-R from Aqueous Solution

The aqai palm stalk (Euterpe oleracea) is a food residue used in its natural form (AS) and also protonated (AAS) as biosorbents for the removal of the textile dye Procion Blue MX-R from aqueous solutions. This biosorbent was characterized by infrared spectroscopy, scanning electron microscopy, and nitrogen adsorption-desorption curves. The effects of pH, biosorbent dosages, and shaking time on the biosorption capacities were studied. In the acidic pH region (pH 2.0) the biosorption of the dye was favorable. The minimum contact time to obtain the equilibrium was 8 hours for AS and AAS biosorbents. The general order kinetic model provided the best fit to the experimental data compared with the pseudo-first order and pseudo-second order kinetic adsorption models. The equilibrium data were fitted to the Langmuir, Freundlich, and Sips isotherm models. For both dyes the equilibrium data were best fitted to the Sips isotherm model. The enthalpy and entropy of adsorption of PB were obtained from adsorption equilibrium experiments ranging from 298 to 323 K. Simulated dyehouse effluent was used to check the applicability of the proposed adsorbents for effluent treatment.     

Adsorption isotherms,kinetic, and desorption studies on removal of toxic metal ions from aqueous solutions by polymeric adsorbent

Adsorption of Cd(II), Co(II), and Ni(II) on aminopyridine modified poly(styrene‐alt‐maleic anhydride) crosslinked by 1,2‐diaminoethane as an ion exchange resin has been investigated in aqueous solution. Adsorption behavior of these metal ions on the resin was studied by varying the parameters such as pH (2–6), adsorbent dose (0–4.0 g/L), contact time (0–240 min), and metal ions concentration (20–300 mg/L). Adsorption percentage was increased by increasing each of these parameters. The isotherm models such as: Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich were used to describe adsorption equilibrium. The results showed that the best fit was achieved with the Langmuir isotherm equation, yielding maximum adsorption capacities of 81.30, 49.02, and 76.92 mg/g for Cd(II), Co(II), and Ni(II), respectively. The pseudo‐first‐order, pseudo‐second‐order, and intra‐particle diffusion kinetics equations were used for modeling of adsorption data and it was shown that pseudo‐second‐order kinetic equation could best describe the adsorption kinetics. The intra‐particle diffusion study revealed that external diffusion might be involved in this case. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41642.     

不同分子质量的腐殖酸对溴离子在MIEX树脂上吸附行为的影响

采用静态吸附法研究了不同分子量的腐殖酸对溴离子(Br?)在MIEX树脂上吸附行为的影响. 结果表明,pH为中性时,4种腐殖酸(分子量分别为小于1000, 1000?5000, 5000?10000, 大于10000)使MIEX树脂对Br?的去除率从80.05%分别降至75.39%, 26.32%, 42.67%和49.03%,而酸性(pH<5.0)或碱性(pH>9.0)时,各种腐殖酸则会促进Br?去除,pH为11.0时去除效率增加最明显. 分子量大于10000的腐殖酸可将吸附平衡时间由60 min缩短至20 min,分子质量1000?5000和5000?10000的腐殖酸可将吸附平衡时间缩短至40 min. 但不论有无腐殖酸,MIEX树脂对Br?的吸附过程均符合拟二级反应动力学模型. 不同分子量的腐殖酸均能明显降低Br?在MIEX树脂上的吸附平衡容量,分子量大于10000的腐殖酸影响最大,但均不改变吸附平衡模型类型,吸附平衡规律用Langmuir与Freundlich模型均可很好描述. 不同分子量的腐殖酸对MIEX树脂去除Br?的影响与溶液pH值密切相关,腐殖酸会加速Br?在树脂上的吸附过程,但不改变吸附平衡及动力学模型类型.     

Adsorption studies of Cr(III) ions from aqueous solutions by DEHPA impregnated onto Amberlite XAD7 – Factorial design analysis

The present paper investigates the adsorption of Cr(III) ions using the SIR, prepared by impregnation of Amberlite XAD7 with di-(2-ethylhexyl)-phosphoric acid (DEHPA), which has been chosen as an extractant for the purpose of this study. The Amberlite XAD7–DEHPA resin was impregnated with DEHPA and ethylic alcohol as solvent trough dynamic column impregnation method. The influence of different physicochemical parameters (pH, resin dosage, initial concentration of Cr(III) ions, contact time and temperature) upon the adsorption capacity of XAD7–DEHPA, in the Cr(III) ions removal process from aqueous solution, has been investigated. The pH for Cr(III) ions adsorption was found as 3.0 for this material. The results showed that the adsorption equilibrium was reached after 45 min. The adsorption process is best described by the pseudo-second order kinetic model. Langmuir adsorption isotherm gave a satisfactory fit of the equilibrium data. The maximum adsorption capacity is ∼3 mg Cr(III) ions/g SIR. The thermodynamic studies allowed us to determine the thermodynamic parameters ΔG°, ΔH° and ΔS°. In this paper the factorial design of experiments was used to study the performance of the adsorption process.     

Removal Of methylene blue dye from simulated wastewater by alginic acid fiber as adsorbent: Equilibrium,kinetic, and thermodynamic studies

Alginic acid fiber was used as a novel adsorbent to remove methylene blue from aqueous solution, and adsorption mechanisms were investigated. System variables, including contact time, pH, temperature, and initial concentration were examined to investigate the effect on adsorption in batch experiments. The results showed that equilibrium reached in less than 20 min and pH significantly influenced the equilibrium value. Langmuir, Freundlich, and Temkin isotherm models were employed to analyse the isotherm behaviours. It was found the isotherm behaviours conform to Freundlich and Temkin models well, indicating a chemisorption process. Pseudo‐first‐order, pseudo‐second‐order, and intraparticle diffusion models were employed to investigate kinetic behaviours. The kinetic behaviour is best described by pseudo‐second‐order model. Thermodynamic parameters indicate that the process is spontaneous and exothermic.     

Adsorption of lithium ions on lithium-aluminum hydroxides: Equilibrium and kinetics

The rapid development of rechargeable lithium batteries has promoted the demand of primary lithium products obtained from lithium-bearing resources, especially salt lakes. Layered lithium-aluminum hydroxides connecting with ion exchange resin were used for the adsorption of lithium ions from aqueous resources. Batch experiments were conducted to determine the effects of pH, initial lithium concentration, and contact time on lithium adsorption. The optimal conditions for lithium adsorption were found to be pH = 7, and the equilibrium time is approximately 600 minutes. The selectivity experiment indicated that the adsorbent showed selectivity toward lithium ion, so the adsorbent could be used in the separation of lithium ion with other metal ions, especially the divalent magnesium ions. The experiment showed that the existence of the magnesium chloride enhanced the lithium adsorption onto the adsorbent greatly. The kinetic data were analyzed by several kinetic models, and the best result was achieved with a pseudo-second-order model. The commonly used adsorption isotherms were used to fit the experimental data by nonlinear regression. Both Langmuir and Temkin isotherm models could describe the isotherm well. The thermodynamic parameters (ΔG, ΔS, and ΔH) were also calculated subsequently and the results showed the lithium adsorption process is exothermic with the decrease of randomness. Breakthrough curves demonstrated the cyclic stability of the adsorbent and the influence of the feed flow rate. Lithium ions were effectively adsorbed from the aqueous solution by the adsorbent, demonstrating its feasibility for lithium recovery and providing the fundamental data for further column design.     

Adsorption of Cr(III), Ni(II), Zn(II), Co(II) ions onto phenolated wood resin

In this study, phenolated wood resin was used an adsorbent for the removal of Cr(III), Ni(II), Zn(II), Co(II) ions by adsorption from aqueous solution. The adsorption of metal ions from solution was carried at different contact times, concentrations and pHs at room temperature (25°C). For individual metal ion, the amount of metal ions adsorbed per unit weight of phenolated wood resin at equilibrium time increased with increasing concentration and pH. Also, when the amounts of metal ions adsorbed are compared to each other, it was seen that this increase was order of Cr(III) > Ni(II) > Zn(II) > Co(II). This increase was order of Cr(III) > Ni(II) > Co(II) > Zn(II) for commercial phenol–formaldehyde resin. Kinetic studies showed that the adsorption process obeyed the intraparticle diffusion model. It was also determined that adsorption isotherm followed Langmuir and Freundlich models. Adsorption isotherm obtained for commercial phenol–formaldehyde resin was consistent with Freundlich model well. Adsorption capacities from Langmuir isotherm for commercial phenol–formaldehyde resin were higher than those of phenolated wood resin, in the case of individual metal ions. Original adsorption isotherm demonstrated the monolayer coverage of the surface of phenolated wood resin. Adsorption kinetic followed the intraparticle diffusion model. The positive values of ΔG° determined using the equilibrium constants showed that the adsorption was not of spontaneous nature. It was seen that values of distribution coefficient (K_D) decreasing with metal ion concentration in solution at equilibrium (C_e) indicated that the occupation of active surface sites of adsorbent increased with metal ions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2838–2846, 2006     

除镍离子交换树脂的优选及其效能的研究

为优选除Ni~(2+)交换树脂,采用电镀镍废水(Ni~(2+)的质量浓度为80 mg/L)研究了5种阳离子交换树脂对Ni~(2+)的吸附等温式和吸附动力学,考察了其对电镀镍废水中Ni~(2+)的吸附交换容量、吸附交换速率、再生性能以及废水中共存离子对树脂处理电镀镍废水效能的影响。结果表明,在120 min内5种阳离子树脂对Ni~(2+)的吸附基本达到平衡,吸附等温线均符合Freundlich吸附,吸附动力学均遵循准二级动力学方程;KP752和CH-90树脂对Ni~(2+)吸附交换容量分别为22.421和22.831 mg/g,吸附效果最好,并且2种树脂对Ni~(2+)的回收率都可达80%以上;共存的Ca~(2+)、Mg~(2+)会显著影响CH-90树脂吸附Ni~(2+)的效果,而对KP752树脂的影响较小。     

Boron removal from aqueous solutions by ion-exchange resin: Batch studies

In this study, boron removal from aqueous solutions was examined using Dowex 2 × 8 anion exchange resin. The sorption behaviour of resin was investigated as a function of pH, contact-time and temperature, initial boron concentration of solution, resin dosage and effect of other ions. The maximum sorption value for boron was observed at pH 9. The percent removal of boron decreased as temperature and initial boron concentration increased. The presence of other ions in solutions affected the sorption of boron significantly. The Langmuir isotherm was used to describe observed sorption phenomena. The maximum sorption capacity of Dowex 2 × 8 was determined as 16.98 mg B/g at pH 9 and 25°C. The quantitative stripping of boron from resin was obtained with 0.5 M H₂SO₄ or 0.5 M HCl solutions at 25°C. A generalised ion exchange kinetic model was applied to fit the kinetic data obtained by using the Dowex 2 × 8 and the rate-determining step is determined as film-intraparticle diffusion.     

Toxic metal ion removal by terpolymer ion-exchanger from aqueous environments: synthesis,thermal degradation,batch separation,kinetic and isotherm studies

A novel chelating resin was synthesized and characterized by elemental, physico-chemical, GPC, NMR, and SEM analyses. Batch separation was adopted to study the recovery of selected metal ions with respect to the pH, time, concentrations, and electrolytes. From the results, it was observed that the order of the rate of metal ion uptake by the resin was Fe³⁺ > Cu²⁺ > Zn²⁺ > Ni²⁺ > Co²⁺ > Pb²⁺ ions. The adsorption kinetics follows first order, and isotherm models were also found to fit each other. The resin showed three-step thermal degradation, and its kinetic and thermodynamic parameters were also evaluated.     

Investigation of adsorption of lead,mercury and nickel from aqueous solutions onto carbon aerogel

Recently a new form of activated carbon has appeared: carbon aerogel (CA). Its use for the removal of inorganic (and especially metal ions) has not been studied. In the present study, the adsorption of three metal ions, Hg(II), Pb(II) and Ni(II), onto carbon aerogel has been investigated. Batch experiments were carried out to assess adsorption equilibria and kinetic behaviour of heavy metal ions by varying parameters such as agitation time, metal ions' concentration, adsorbent dose and pH. They facilitated the computation of kinetic parameters and maximum metal ion adsorption capacities. Increasing the initial solution pH (2–10) and carbon concentration (50–500 mg per 50 cm³) increases the removal of all three metal ions. A decrease of equilibrium pH with an increase of metal ion concentration led us to propose an adsorption mechanism by ion exchange between metal cations and H⁺ at the carbon aerogel surface. Carboxylic groups are especially involved in this adsorption mechanism. Langmuir and Freundlich isotherm models were used to analyse the experimental data of carbon aerogel. The thermodynamics of the metal adsorption was also investigated for the practical implementation of the adsorbent. The sorption showed significant increase with increase of temperature. Kinetics models describing the adsorption of Hg(II), Pb(II) and Ni(II) ions onto carbon aerogel have been compared. Kinetics models evaluated include the pseudo‐first order and second order model. The parameters of the adsorption rate constants have been determined and the effectiveness of each model assessed. The result obtained showed that the pseudo‐second order kinetic model correlated well with the experimental data and better than the pseudo‐first order model examined in the study. Mass transfer coefficients obtained can be useful in designing wastewater treatment systems or in the development of environmental technologies. Copyright © 2005 Society of Chemical Industry     

短孔道介孔二氧化硅SBA-15对铀的吸附性能

以短孔道介孔二氧化硅SBA-15为铀吸附剂,考察吸附时间、初始液pH、初始浓度对吸附性能的影响,并分析了吸附动力学和吸附等温线以及吸附前后红外光谱变化。结果表明,初始液pH对吸附具有重要的影响,最佳吸附的pH值为6; 吸附在30 min即可达到平衡; 当初始浓度为100 mg·L^-1时,饱和吸附量为311 mg·g^-1;吸附量随铀溶液初始浓度的增大而增大,而吸附百分数则相反;吸附等温线符合Langmuir和Freundlich吸附模型,吸附动力学符合准二级动力学方程;吸附过程中起主要作用的基团是Si-OH和Si-O-Si。     

Cleaning Water Contaminated with Heavy Metal Ions Using Pyrolyzed Biochar Adsorbents

The extraction of pollutants from water using activated biochar materials is a low cost, sustainable approach for providing safe water in developing countries. The adsorption of copper ions, Cu(II), onto pyrolyzed and activated dried banana peel was studied and compared with the adsorption of copper ions onto a commercial activated carbon, F-400. Both the physical and chemical properties of the banana peel and activated carbon were measured. Pyrolysis of dried banana peels resulted in the formation of a large, porous surface area adsorbent with strongly negative surface charges.

Screening studies, which were designed to evaluate the effect of the mass of the adsorbent, pH of the solution, tumbling time, and initial Cu(II) concentration were conducted for each adsorbent. Equilibrium adsorption data were also analyzed, and the Freundlich isotherm resulted in a better fit than the Langmuir isotherm. The degree of favorability of adsorption of Cu(II) ions and adsorption capacity were 1.25 and 351.1 mg/g for pyrolyzed banana peel, respectively. The sorption kinetics fit a pseudo-second order equation. The mechanism of adsorption of metal ions on pyrolyzed banana peel followed ion exchange and electrostatic interactions resulting in the complexation of adsorbed ions.