2-萘磺酸/硫酸在弱碱性树脂上的吸附平衡研究

Experiments for single and bisolute competitive adsorption were carried out to investigate the adsorption behavior of β-naphthalenesulfonic acid(NSA and sulfuric acid from their solution at 25℃ onto weakly basic resin D301R,Adsorption affinity of sulfuric acid on D301R was found to be much higher than that of NSA.The data of single-solute adsorption were fitted to the Langmuir model and the Freundlich adsorption model.The ideal adsorbed solution theory(IAST) coupled with the single-solute adsorption models were used to predict the bisolute competitive adsorption equilibria.The IAST coupled with the Langmuir and the Freundlich model for sulfuric acid and NSA.Respectively,yields the favorable representation of the bisolute competitive adsorption behavior.     

弱碱性树脂处理β-萘磺酸废水的吸附分离热力学性能

研究了β-萘磺酸废水中β-萘磺酸、H₂SO₄、H₂SO₃ 单组分吸附平衡,并以Langmuir、Freundlich模型对其进行模拟.吸附过程的热力学计算及分析结果表明,吸附过程为放热的化学吸附过程,吸附量顺序为H₂SO₄>NSA>H₂SO₃,推动力大小顺序为H₂SO₄>NSA>H₂SO₃,吸附过程熵增加.以D301R弱碱性树脂为吸附剂,可有效地实现三者的分离.     

Sequential competitive sorption and desorption of chlorophenols in organoclay

Single- and bi-solute sorption and desorption of 2-chlorophenol (2-CP) and 2,4,5-trichlorophenol (2,4,5-TCP) in montmorillonite modified with hexadecyltrimethyl-ammonium (HDTMA) were investigated by sequential sorption and desorption. Effect of pH on the sequential sorption and desorption was investigated. As expected by the magnitude of octanol: water partition coefficient (K_ow), both sorption and desorption affinity of 2,4,5-TCP was higher than that of 2-CP at pH 4.85 and 9.15. For both chlorophenols, the protonated speciation (at pH 4.85) exhibited a higher affinity in both sorption and desorption than the predominant deprotonated speciation (about 80% and 99% of 2-chlorophenolate and 2,4,5-trichlophenolate anions at pH 9.15, respectively). Desorption of chlorinated phenols was strongly dependent on the current pH regardless of their speciation in the previous sorption stage. Freundlich model was used to analyze the single-solute sorption and desorption data. No appreciable desorption-resistant (or non-desorbing) fraction was observed in organoclays after several sequential desorptions. This indicates that sorption of phenols in organoclay mainly occurs via partitioning into the core of the pseudo-organic medium, thereby causing desorption nearly reversible. In bisolute competitive systems, sorption (or desorption) affinity of both chlorophenols was reduced compared to that in its single-solute system due to the competition between the solutes. The ideal adsorbed solution theory (IAST) coupled with the single-solute Freundlich model was positively correlated with the bisolute sequential competitive sorption and desorption equilibria.     

Sorption of Acid Dyes onto Silica Modified with Cetyltrimethylammonium Cations

The sorption behavior of acid dyes onto cetyltrimethylammonium bromide (CTAB)- modified silica as a function of pH in the aqueous medium was studied. Single- and multi-solute sorption equilibria of orange Ⅱ(OR), phenol red (PR) and Eriochrome Black T (EBT) were studied at pH 3, unbuffered water pH and pH 11. Sorption behavior of EBT could not be conducted at pH 3 due to its aggregation in acidic medium. All the reaction conditions, experimental protocols and techniques remained the same throughout the sorption process. Sorption isotherms for single-solute system were fitted by the Langmuir model, while Langmuir competitive model (LCM) and the ideal adsorbed solution theory (IAST) coupled with Langmuir model (IAST/Langmuir) were used for the prediction of multisolute competitive sorption. Sorption affinities influenced by the factors like physical interactive forces between the molecules of CTA on silica and sorbate, structural limitations of the dyes based on their geometrical arrangement were investiga     

Efficiently removing phenols from aqueous solution using amino acid functionalized D301 resins

ABSTRACT

Amino acid functionalized D301 resins (Tyr-D301, Phe-D301, and Ala-D301) are successfully prepared to remove phenols. The influences of adsorption condition on adsorption ability and the practical application value are investigated. The functionalized D301 resins possess strong adsorption ability toward phenol by ways of hydrogen bond interaction. The adsorption capacity of Tyr-D301, Phe-D301, and Ala-D301 is 388.2, 368.4, and 321.5 mg· g^?1 at 293 K and pH of 2, respectively. The adsorption process could be described satisfactorily by Lagergren-first-order model and Langmuir model. The rate constant is 0.057, 0.042, and 0.035 min^?1, respectively. The functionalized D301 can be used to dispose wastewater containing phenols.     

以弱碱性树脂去除废水中5-氨基-2-氯苯-4-磺酸和盐酸

This research deals with an investigation of the adsorption of two acids, namely, 5-amino- 2-chlorotoluene-4-sulfonic and chlorhydric acids from their solution onto weakly basic resin. The screening of resins, kinetics, and isotherm were studied. The results indicate that the D301R is more appropriate for the removal of acids from solution. The adsorption of acids obeys Langmuir isotherm and the first-order kinetics model. Sorptive affinity of the two acids on D301R was found to be in the order of 5-amino-2-chlorotoluene-4-sulfonic acid〉 chlorhydric acid. Thermodynamic parameters for the adsorption of acids were calculated and discussed. The maximum removal of acids was observed around 97% and 76% at 25℃ for 5-amino-2-chlorotoluene-4-sulfonic acid and chlorhydric acid, respectively.     

Competitive adsorption of protocatechuic acid and caffeic acid on C18 particles

Comparisons of protocatechuic acid (PA) and caffeic acid (CA) adsorption isotherm on C₁₈ column and competitive adsorption of the two compounds were investigated. By linear and nonlinear regression analysis, the experimental parameters in the equilibrium isotherms were estimated. Adsorption equilibrium data of the two compounds were investigated using six different models including linear, Langmuir, Freundlich, Langmuir-Freundlich, competitive Langmuir and Quadratic. In the moderate range of concentrations, the competitive Langmuir isotherm proved to be the best model for these experimental data. The regression coefficients of the competitive Langmuir adsorption isotherms were 0.9860 for PA and 0.9898 for CA, respectively. The coefficients obtained for the six isotherm models confirmed the superiority of the competitive Langmuir isotherm for analyzing the competitive adsorption data of solutes.     

A comparison of isotherm and kinetic models for binary-solute adsorption to affinity membranes

Single-solute isotherms for pepsin (EC 3.4.23.1) and chymosin (EC 3.4.23.4) adsorption to affinity membranes were fitted using five of the most popular isotherm models. It was found that the single-solute Langmuir isotherm was the best two-parameter model, although the three-parameter models gave even better fitting. Experimental binary-solute adsorption isotherms were compared with four different types of binary-solute Langmuir models using the single-solute parameters. The results showed that the difference in the saturation capacities affected the adsorption equilibrium. Furthermore, three types of binary-solute Langmuir models were converted into the kinetic form and used to calculate the association rate constants of pepsin and chymosin from experimental data. The best-fitted rate constant values were found to be identical for different kinetic models. However, the model predictions of association curves were significantly influenced when the values of association rate constants were changed.     

MODELLING OF PROTEIN ADSORPTION IN A FIXED-BED: SINGLE AND TWO-SOLUTE BREAKTHROUGH BEHAVIOUR

Single- and two-solute adsorption breakthrough curves of lysozyme and bovine serum albumin on the cation exchanger SP-Sepharose Fast Flow were studied in this paper. A simplified mathematical model was used to model these data. Input parameters of the model such as equilibrium and kinetic parameters were estimated from single-solute batch experiments. For single-component adsorption in a fixed-bed, the breakthrough behaviour of lysozyme was well modelled. In contrast, significant deviations were observed between the measured and theoretical breakthrough curves of albumin. It was shown that the equilibrium parameters measured from batch experiments failed to account for the behaviour of albumin in the fixed-bed. The bisolute system consisting of the simultaneous adsorption of lysozyme and albumin was also modelled using the same set of parameters derived from single-solute batch experiments. Deviations were observed between the measured and theoretical breakthrough curves for both proteins, indicating that the effects of multicomponent equilibria and kinetics must be taken into consideration in parameter estimation.     

Comparison of adsorption equilibrium of glycyrrhizic acid and liquiritin on C18 column

The adsorption isotherms of glycyrrhizic acid (GA) and liquiritin (LQ) on a C₁₈ column were compared and the competitive adsorption of the two compounds was investigated. The experimental parameters in the equilibrium isotherms were estimated by linear and nonlinear regression analyses. The adsorption equilibrium data were correlated into the linear, Langmuir, competitive Langmuir, Freundlich, and Langmuir–Freundlich isotherm models. Over a moderate concentration range, the competitive Langmuir isotherm provided the best fit to the experimental data. The regression coefficients of the competitive Langmuir adsorption isotherms were 0.9754 and 0.9855 for the mixtures of GA and LQ, respectively. The coefficients obtained for the five isotherm models confirmed the superiority of the competitive Langmuir isotherm for analyzing the adsorption data of solutes.     

Adsorption behavior of cesium and strontium onto chitosan impregnated with ionic liquid

We briefly studied the adsorption behavior of chitosan impregnated with an ionic liquid (1-ethyl-3-methyl imidazolium chloride) in solutions with Cs⁺ and Sr²⁺ ions. The impregnation of chitosan was realized by ultrasonication method. The impregnated chitosan was analyzed by FTIR, SEM, and EDX in order to show that the chitosan was impregnated with the studied IL. The adsorptive properties of ionic liquid-impregnated chitosan for the removal of Cs⁺ and Sr²⁺ ions from aqueous solutions were studied in a batch adsorption system. The adsorption kinetic was found to follow a pseudo-second-order kinetic model. The experimental data showed good fit to the Langmuir isotherm. The adsorption properties of the chitosan impregnated with the studied ionic liquid were determined in binary, tertiary, and quaternary systems. The adsorption capacity of the IL impregnated chitosan is not significant influenced in the binary systems. The adsorption capacity of the IL impregnated chitosan decreases with the increase of the number of the cation present in solutions. It was observed that the studied adsorbent has a higher affinity for Cs⁺ ions than for Sr²⁺ ions.     

水杨酸和磺基水杨酸在D201树脂上的共吸附行为

采用静态法和动态法研究了水溶液中水杨酸和磺基水杨酸在D201树脂上的共吸附行为和吸附选择性。同时竞争吸附、预负荷竞争吸附和等温吸附的结果均表明:水杨酸的存在对磺基水杨酸的吸附影响较小,而磺基水杨酸的存在则大大削弱了水杨酸的吸附2,种溶质在吸附位点上的竞争为主要作用机制。在双溶质(质量浓度比为1∶1)吸附体系中,初始质量浓度对吸附选择性的影响明显,初始质量浓度≤500 mg/L时,树脂对水杨酸或磺基水杨酸的吸附选择性均很小;初始浓度为1 000—2 000 mg/L时,树脂对磺基水杨酸有很高的吸附选择性,利于二者的选择吸附分离。对初始质量浓度均为2 000 mg/L的双溶质水溶液的动态吸附与脱附表明,以1.000 g树脂装柱,吸附出水在250 mL泄漏点内几乎只含水杨酸,磺基水杨酸被吸附于树脂上。室温下以质量分数5%NaCl+2%NaOH溶液作为脱附剂,可完全洗脱树脂上吸附的磺基水杨酸和水杨酸,其分离系数为300,磺基水杨酸的回收率为96%。应用D201树脂能有效实现磺基水杨酸与水杨酸的选择性吸附分离。     

An isotherm model describing concave-down scatchard curve for heterogeneous affinity adsorption

A new isotherm model, derived for a concave-down Scatchard curve, is presented to fit the experimental results for pepsin and chymosin adsorption to pepstatin A affinity membranes. The new model is converted into a kinetic expression and used for the fitting of association curves. The results from the new kinetic model show a better agreement with the experimental data than the Langmuir kinetic model. The new kinetic model is also used together with the affinity membrane model to predict the single-solute breakthrough curves, which performs well in matching the experimental curves. ©1997 SCI     

Removal of Chromium(VI) Using Surface Modified Superparamagnetic Iron Oxide Nanoparticles

This study describes the removal of Chromium(VI) from aqueous solutions using surface tailored superparamagnetic iron oxide nanoparticles (SPION) coated with bis(2,4,4-trimethylpentyl)dithiophosphinic acid (Cyanex-301). The synthesized Cyanex-301 coated SPION has been characterized by Transmission Electron Microscopy (TEM), Fourier-Transfer Infrared Spectroscopy (FT-IR), X-ray Photonic Spectroscopy (XPS), and Thermogravimetric Analysis (TGA). The adsorption mechanism was proposed to be via complexation between the thiol group on Cyanex-301 and Cr(VI) ions based on the XPS and FTIR analysis. It has been found that the equilibrium can be attained in less than 2 hr. The adsorption behavior of Cr(VI) on the Cyanex-301 coated SPION can be well described by the Langmuir model and the maximum adsorption capacity for Cr(VI) was estimated to be 30.8 mg/g. The selectivity of the Cyanex-301 coated SPION adsorbent towards Cr(VI) ions was found to be high and the maximum loading capacity obtained is up to an order of magnitude higher than that of other adsorbents reported in the literature. The desorption studies showed that more than 70% of Cr(VI) can be recovered using HNO₃ as eluting solution. Our findings suggest a high potential of the designed adsorbent material for the treatment of industrial wastewater containing Cr(VI).     

Removal atrazine using two anion-exchange resins supported nanohydrous metal-oxide particle

Hydrous iron oxide and hydrous aluminum oxide were loaded successfully onto a polymeric adsorbent (D301) to modify adsorbing materials (HIOD301 and HAOD301). The adsorptive equilibrium of atrazine was investigated in an aquatic environment using HIOD301 and HAOD301 under different experimental conditions. The results indi-cated that both HIOD301 and HAOD301 showed good adsorption capacities for atrazine at pH 4. The Langmuir and Freundlich isotherm equations were used to study the interactions between the adsorbate and adsorbent. The adsorption kinetics of atrazine at different concentrations was well described in terms of a pseudo-second-order equation in regard to the correlation coefficients and adsorption capacity. The removal percentages of atrazine for HIOD301 and HAOD301 were still more than 95%in the presence of sodium chloride.     

Treatment of DSD acid wastewater using a weak basic resin

The D301R resin was screened to separate DSD acid from DSD acid wastewater. The effect of pH, temperature and time on adsorption behavior was investigated. Batch experiments indicated that the COD removal ratio of DSD acid wastewater was over 86%, and the COD of treated wastewater was under 100 mg/L at appropriate operating conditions. The results of column dynamic adsorption and regeneration showed that COD could be efficiently removed by the D301R resin from DSD acid wastewater, and the resin was easily regenerated by NaOH stripping.     

以弱碱性树脂去除废水中5-氨基-2-氯甲苯-4-磺酸和盐酸：平衡及动力学

考察了废水中5-氨基-2-氯甲苯-4-磺酸（CLT）和盐酸（HCl）在弱碱性离子交换树脂D301R上的吸附。研究了吸附平衡及动力学行为。结果表明两种酸在D301R树脂上的吸附遵循Langmuir吸附平衡模型;CLT吸附动力学过程与二级反应模型相吻合;HCl与一级反应模型吻合得较好;吸附过程为孔扩散控制。CLT在树脂上的吸附度大于HCl。计算了吸附过程热力学参数并进行了讨论。     

D301大孔吸附树脂吸附甘氨酸

通过静态吸附法研究了树脂D301对水溶液中甘氨酸的吸附行为。采用单因素实验法确定了最佳吸附条件为pH 7.5,温度35℃,时间45 min,吸附剂用量为0.1 g,在此条件下最大平衡吸附量可达794.81 mg·g^-1。同时探究了D301对甘氨酸溶液吸附的热力学行为,测得了303.15～318.15 K温度范围内的吸附等温线数据,用Langmuir、Freundlich、Temkin方程对此进行拟合,并根据热力学原理计算得到吸附过程中ΔH^θ、ΔG^θ、ΔS^θ值和吸附表观活化能。结果表明等温吸附平衡符合Langmuir等温线模型,其ΔH^θ 134.75 kJ·mol^-1,ΔG^θ-6.312 kJ·mol^-1, ΔS^θ 450.806 J·mol^-1·K^-1,E_a为81.27 kJ·mol^-1。研究结果表明D301对甘氨酸的吸附为化学吸附和物理吸附共存且为自发进行的吸热过程。     

Competitive adsorption of two dissolved organics onto activated carbon—III: Adsorption kinetics in fixed beds

Adsorption breakthrough curves for bisolute systems of dissolved organics on activated carbon are measured in fixed beds.Results for strongly adsorbable species indicate that at low liquid concentrations (X<0.1 mmol/l.) only external mass transfer resistance is rate determining.However, at higher liquid concentrations internal mass transfer becomes increasingly significant. Breakthrough behaviour is predicted using alternatively three different models with different assumptions about diffusion in the liquid filled pores and diffusion on the surface in series with external film diffusion.Multi-solute adsorption equilibria are predicted from single-solute data using the ideal adsorbed solution theory developed by Myers and Prausnitz, while the single-solute equilibria are represented by Freundlich isotherms. The external mass transfer coefficient for each component is calculated by a general correlation for heat and mass transfer in fixed beds. The internal diffusion coefficient for each component is determined in batch reactor tests with the single-solute system.Systematic deviations between measured breakthrough curves and those calculated from different models using only single-solute data are observed in all experiments with mixed solutes if there is significant internal diffusional resistance and marked displacement of one component inside the carbon particles. The deviations may be due to mutual interference of diffusing molecules. A better agreement between calculated and observed breakthrough curves can be obtained using an extended model in which mixture data are required.     

Adsorption of Phenol and Nitrophenol Isomers onto Montmorillonite Modified with Hexadecyltrimethylammonium Cation

ABSTRACT

Single- and two-component competitive adsorptions were carried out in a batch adsorber to investigate the adsorption behavior of phenol and 2-, 3-, and 4-nitrophen-ols in aqueous solution at 25°C onto hexadecyltrimethylammonium (HDTMA)-treated montmorillonite. HDTMA cation was exchanged for metal cations on the montmorillonite to prepare HDTMA—montmorillonite, changing its surface property from hydrophilic to organophilic. Effective solid diffusivity of HDTMA cation in the montmorillonite particle was estimated to be about 3 × 10^?12 cm²/s by fitting the film-solid diffusion model to a set of HDTMA adsorption kinetic data onto mont-morillonite. Adsorption affinity on HDTMA—montmorillonite was found to be in the order 3-nitrophenol = 4-nitrophenol > 2-nitrophenol > phenol. The Langmuir and the Redlich—Peterson (RP) adsorption models were used to analyze the single component adsorption equilibria. The ideal adsorbed solution theory (IAST) and the Langmuir competitive model (LCM) were used to predict the multicomponent competitive adsorption equilibria. These models yielded favorable representations of both individ-ual and competitive adsorption behaviors.