化学修饰的吸附树脂对2,4,6-三氯苯酚的吸附研究

合成了用邻羧基苯甲酰基或苯甲酰基修饰的新型聚苯乙烯-二乙烯苯吸附树脂ZH-01, ZH-02和ZH-03, 利用瓶点法研究了它们和Amberlite XAD-4对288～318 K下水溶液中2,4,6-三氯苯酚的静态吸附和静态脱附特征以证实吸附质与吸附剂之间存在化学吸附, 并利用半经验分子轨道法(AM1)计算的几种吸附剂和2,4,6-三氯苯酚的前线轨道近似能级进行了解释. 结果表明: 经邻羧基苯甲酰基或苯甲酰基化学修饰后的树脂ZH-01, ZH-02和ZH-03对水溶液中2,4,6-三氯苯酚的吸附过程在合适温度时会使酚羟基和吸附剂表面的羰基发生作用, 对吸附剂进行适当的化学修饰后, 对2,4,6-三氯苯酚的穿透吸附容量均为Amberlite XAD-4树脂的150%, 饱和吸附容量是Amberlite XAD-4树脂的114％～128％.     

RECOVERY OF p-AMINOPHENOL （PAP） FROM AQUEOUS SOLUTION BY HYPER-CROSS-LINKED RESIN AND ITS USE FOR WASTEWATER TREATMENT

p-Aminophenol （PAP）, a typical amphoteric compound, has been widely used as raw chemical material and important interrnediate in various fields. To study on the recovery of PAP, an experimental comparison of the adsorption and desorption properties of PAP onto three types of hyper-cross-linked resins in aqueous solutions was performed. This paper focuses on the static equilibrium adsorption and desorption behaviors, the adsorption thermodynamics, the column dynamic adsorption and desorption, and other influencing factors of adsorption, such as temperature and pH values. All the isothermal data fit well to the Freundlich model. The capacity of equilibrium adsorption for PAP on NG-10 is the highest within the temperature range 288K-318K, which may greatly contribute to the advantage in specific surface area, especially the micropore area, of the adsorbent. While in the desorption experiments, NG-9 achieved relative well regeneration efficiency whether by ethanol or by 4% hydrochloric acid. Furthermore, the results of column tests and field applications were also proved that NG-9 was an effective sorbent for the reclamation PAP from wastewater.     

Application of the Polanyi potential theory to phthalates adsorption from aqueous solution with hyper-cross-linked polymer resins

The adsorption equilibria of dimethyl phthalate (DMP) and diethyl phthalate (DEP) on two hyper-cross-linked polymer resins (NDA-99 and NDA-150) in aqueous solution were investigated at 298 K. And a coal-based granular activated carbon (AC-750) was chosen for comparison. All the adsorption equilibrium data of DMP were well fitted by the Polanyi-based isotherm modeling (Polanyi-Manes (PM) equation), and the characteristic curves of the three adsorbents were obtained. It is noteworthy that a reasonably good agreement was obtained between the combined micropore and mesopore volume of adsorbents and the corresponding adsorption volume capacity for phthalates. Compared to the granular activated carbon (AC-750), the greater adsorption performances of the two resins (NDA-99 and NDA-150) were assumed to result from their more abundant micro- and mesopore structure, where phthalates can be intensively adsorbed by pore-filling mechanism. According to the exponent b value of the PM equation, NDA-99 and NDA-150 show the more micro- and mesopore heterogeneity than AC-750. On the other hand, the functional groups on the adsorbent surfaces did not take a notable effect on the adsorption equilibria of phthalates. The theory equilibrium adsorption amounts of DEP, predicted by the specific characteristic curve of each adsorbent, agree well with the experimental ones, respectively. The characteristic curve of hyper-cross-linked polymer resins and its prediction of phthalates adsorption calculated by Polanyi-based isotherm modeling have a potential applicability for field applications.     

胺基化超高交联吸附树脂对苯酚和苯胺吸附行为的研究

在超高交联吸附树脂上负载不同胺基后,无论是在非水体系还是在水体系中,树脂对苯酚的吸附选择性大大增强.非水体系中,树脂对苯胺和苯酚的吸附是靠氢键作用,水体系中,树脂对苯酚的吸附是表面吸附和基团吸附综合作用的结果.动态吸附表明,树脂胺基化前(Rf18)树脂与季铵化后(Rs6 ) ,对苯胺和苯酚混合水溶液的动态吸附泄漏曲线差别较大.对Rf18树脂,苯酚首先在14 7BV(床体积)处泄漏,其泄漏液浓度上升很快,在2 12BV处达吸附饱和,苯胺在184BV处才开始泄漏,且其泄漏液浓度上升缓慢;在14 7～184BV之间可收集到苯酚溶液.对Rs6树脂,苯胺先泄漏(17BV处) ,其泄漏浓度很快趋于水平,在4 7BV处达吸附饱和;苯酚在4 4BV处开始泄漏,其泄漏曲线也上升很快,在79BV处趋于水平,在17～4 4BV之间可收集到苯胺水溶液.     

树脂填充聚醚砜纤维吸附剂对牛血清蛋白吸附性能的研究

重点研究树脂填充聚醚砜(PES)纤维吸附剂与模型蛋白质牛血清蛋白(BSA)之间的吸附与脱附行为.结果表明,蛋白质BSA在树脂填充PES纤维吸附剂中的平衡吸附过程较好地符合朗格缪尔吸附模型,树脂Lewatit CNP80ws填充PES吸附剂的最大吸附容量约为139mg BSA/g吸附剂.表面具有开孔结构的树脂填充PES纤维吸附剂的吸附速率较快,在不同结构纤维吸附剂中BSA的扩散系数在1·82×10-14~8·7×10-14m2/s范围内变化.另外,考察了BSA溶液的pH与洗脱剂等因素对吸附剂吸附与脱附性能的影响,研究结果对蛋白质的实际分离纯化具有重要的参考价值.     

Enhanced adsorption of puerarin onto a novel hydrophilic and polar modified post-crosslinked resin from aqueous solution

A novel of hydrophilic and polar N-vinylpyrrolidone modified post-crosslinked resin was synthesized and the adsorption behaviors toward puerarin from aqueous solution were investigated. The post-crosslinked adsorbent PNVP-DVBpc was prepared by Friedel-Crafts reaction of residual double bonds without external crosslinking agent. The specific surface area of precursor PNVP-DVB increased obviously after post-crosslinking modification. The synthesized adsorbents were characterized by BET surface area, Fourier transform infrared (FTIR), and scanning electron microscopy (SEM). The adsorption behaviors of puerarin from aqueous solution onto precursor PNVP-DVB and post-crosslinked adsorbent PNVP-DVBpc were thoroughly researched. Commercial polymeric adsorbents Amberlite XAD-4 and AB-8 were chosen as the comparison. Among the four media, PNVP-DVBpc presented the largest adsorption capacity of puerarin, which resulted from the synergistic effect of high specific surface area and polar groups (amide groups) onto the adsorbent matrix. Experimental results showed that equilibrium isotherms could be fitted by Freundlich model and the kinetic data could be characterized by pseudo-second order model reasonably. Column adsorption experiments indicated that the puerarin could be completely desorbed by 4.0 BV industrial alcohol. Continuous column adsorption-regeneration cycles demonstrated the PNVP-DVBpc without any significant adsorption capacity loss during operation.     

酚醛型吸附树脂对水体系中吡啶和N,N-二甲基苯胺的吸附性能研究

研究了酚醛型吸附树脂在水体系中对吡啶和N，N-二甲基苯胺的静态和动态吸附行为．结果表明，在水中树脂对吡啶和N，N-二甲基苯胺的吸附主要以疏水吸附机理进行；吸附吡啶和N．N-二甲基苯胺的初始阶段，即达到38．3～48．9％平衡吸附时，吸附速率数据和半经验速率方程很吻合：酚醛型吸附树脂等温吸附吡啶和N，N-二甲基苯胺的平衡吸附数据符合Langmuir方程，相关系数在0．99以上，酚醛型吸附树脂吸附吡啶和N，N-二甲基苯胺属单分子层吸附：用80％的乙醇溶液作洗脱剂来洗脱吸附吡啶已达饱和的JDW-2树脂，效果是很理想的．在3．6个床体积内洗脱率达91．52％，4．8个床体积内洗脱率达到94．85％。表明酚醛型吸附树脂具有优良的洗脱性能．     

大孔吸附树脂分离提取多杀菌素

采用大孔吸附树脂法分离提取多杀菌素.从11种大孔吸附树脂中筛选出DM11进行了静态、动态吸附性能实验,并考察了不同吸附、解吸条件的影响.结果表明,DM11的静态吸附容量为25.63mg/g(wet resin),其吸附等温线符合Langmuir吸附等温式.采用丙酮做洗脱剂,洗脱率为97.5%,动态吸附最佳吸附pH为9.5,吸附流速为6BV/h,穿透吸附容量为21.2mg/ml(wet resin),洗脱流速1.5BV/h.     

STUDIES ON THE ADSORPTION OF PHENOLIC COMPOUNDS ON A PS-BASED RESIN MODIFIED BY NITRO FUNCTIONAL GROUPS

A new adsorbent (JN-01) was prepared by modifying resin NDA-1800 with nitro functional groups.The adsorption capacities of resins XAD-4,NDA-1800 and JN-01 were investigated,and the results indicated that the modified resin JN-01 was much better in adsorbing phenol,p-nitrophenol and p-cresol.The adsorption capacities of the resin JN-01 were higher than those of the resins XAD-4 and NDA-1800 within a temperature range of 283-323 K,which might be attributed to the higher surface area and the partial polarit...     

THE TREATMENT OF SALICYLIC ACID MANUFACTURING WASTEWATER BY HYPERCROSSLINKED POLYMERIC ADSORBENT (NDA-100)

1. INTRODUCTION China is a major producing country of salicylic acid. Salicylic acid is an important intermediate in the manufacture of medicine, food, perfume, dye and so on. Generally, phenol is used as a raw material to manufacture salicylic acid throu…     

氨基酸螯合吸附树脂对Cu2+的吸附行为

合成了一种Ｌ-酪氨酸修饰的螯合吸附树脂（ＡＪＳ-０２）,并与超高交联树脂ＮＤＡ-１５０作对比,研究了其 对Ｃｕ^２＋的吸附和脱附行为。静态实验结果表明,在研究的浓度范围内,吸附平衡数据符合Ｌａｎｇｍｕｉｒ等温吸附方程。Ｃｕ^２＋在ＡＪＳ-０２上的吸附量大于其在ＮＤＡ-１５０上的吸附量。Ｃｕ^２＋在２种树脂上的吸附过程为物理和化学作用的共同结果。吸附动力学符合液膜扩散方程,液膜扩散为吸附速率的主要控制步骤。动态吸附-脱附实验表明,动态穿透吸附量和总吸附量分别为４.０５×１０^－３和６.４４×１０^－３ ｍｏｌ/Ｌ,使用5%HCl进行脱附,脱附率达到90％以上。     

超高交联树脂对苯胺的吸附机理研究

在静态条件下，研究了水溶液中超高交联树脂AM－1和NJ－8及大孔吸附树脂Amberlite XAD－4吸附苯胺的热力学特性，测定了不同温度下的吸附等温线。结果表明，在稀溶液中3种树脂吸附苯胺都符合Langmuir和Freundlich模型，其中AM－1和NJ－8对苯胺的吸附是一个吸热过程；由于AM－1和NJ－8的微孔结构和表面存在酸性基团的吸附中心，对苯胺的吸附是物理吸附和化学吸附共同作用的结果。     

Kinetics of salicylic acid adsorption on activated carbon

The adsorption and desorption of salicylic acid from water solutions was investigated in HPLC microcolumns packed with activated carbon. The adsorption isotherm was obtained by the step-up frontal analysis method in a concentration range of 0-400 mg/L and was well fitted with the Langmuir equation. The investigation of rate aspects of salicylic acid adsorption was based on adsorption/desorption column experiments where different inlet concentrations of salicylic acid were applied in the adsorption phase and desorption was conducted with pure water. The concentration profiles of individual adsorption/desorption cycles data were fitted using several single-parameter models of the fixed-bed adsorption to assess the influence of different phenomena on the column behavior. It was found that the effects of axial dispersion and extraparticle mass transfer were negligible. A rate-determining factor of fixed-bed column dynamics was the kinetics of pore surface adsorption. A bimodal kinetic model reflecting the heterogeneous character of adsorbent pores was verified by a simultaneous fit of the column outlet concentration in four adsorption/desorption cycles. The fitted parameters were the fraction of mesopores and the adsorption rate constants in micropores and mesopores, respectively. It was shown that the former rate constant was an intrinsic one whereas the latter one was an apparent value due to the effects of pore blocking and diffusional hindrances in the micropores.     

Adsorption affinity of certain biomolecules onto polymeric resins: Interpretation from molecular orbital theory

Molecular interactions have been studied for adsorption of certain biomolecules in aqueous solutions using two different types of polymeric resins as adsorbents. Molecular modeling study is based on molecular orbital theory. Adsorption affinity expresses as the slope of the linear region of the isotherm for a solute is found to be different for different adsorbents, and this difference can be interpreted from the differences in sorbent surface chemistry and morphological structure. The adsorptive interaction on the polymeric resins computed on the basis of frontier orbital theory seems to correlate well with the experimentally measured adsorption affinity. Electronic states of adsorbent and adsorbate were calculated using the semiempirical molecular orbital (MO) method from which energy of adsorption in aqueous solution was estimated. It was found that charge transfer interaction plays an important role in the adsorption of certain biomolecules on aqueous solution. The experimentally measured enthalpy of adsorption seems to correlate well with the adsorptive interaction energy computed from molecular orbital theory.     

Hydroxyapatite-coated carboxymethyl chitosan scaffolds for promoting osteoblast and stem cell differentiation

This study investigated the potential of MIEX resin as the adsorbent for the removal of phosphate from aqueous solutions. In our batch experiments, we studied the effect of some parameters on the removal of phosphate. It was observed that uptake of phosphate was mainly affected by initial phosphate concentration, adsorbent dosage, initial pH of solution, and coexistent anions. The adsorption equilibrium data at 288 K fitted well to Freundlich and Koble-Corrigan isotherm models. The kinetics studies displayed that the adsorption process followed the pseudo-second-order model. The diffusion studies showed that the intra-particle diffusion was not the only rate-controlling step and, the diffusion process of phosphate from solution to MIEX resin was controlled by film diffusion. The thermodynamics parameters were evaluated. The results showed that the adsorption process was spontaneous thermodynamically, endothermic, and entropy driven. These results have established a good potentiality for MIEX resin to be used as an adsorbent for the removal of phosphate from aqueous solutions. This work will deepen our understanding of the adsorptive characteristics of phosphate by MIEX resin and provide a better way to remove phosphate from wastewater.     

Kinetic modeling of liquid-phase adsorption of reactive dyes on activated carbon

In this paper, adsorption equilibrium and kinetics of three reactive dyes from their single-component aqueous solutions onto activated carbon were studied in a batch reactor. Effects of the initial concentration and adsorbent particle size on adsorption rate were investigated Adsorption equilibrium data were then correlated with several well-known equilibrium isotherm models. The kinetic data were fitted using the pseudo-first-order equation, the pseudo-second-order equation, and the intraparticle diffusion model. The respective characteristic rate constants were presented. A new adsorption rate model based on the pseudo-first-order equation has been proposed to describe the experimental data over the whole adsorption process. The results show that the modified pseudo-first-order kinetic model generates the best agreement with the experimental data for the three single-component adsorption systems.     

Removal of uranium(VI) from aqueous solution using citric acid modified pine sawdust: batch and column studies

This study described adsorption of uranium(VI) by citric acid modified pine sawdust (CAMPS) in batch and fixed-bed column modes at 295 K. The equilibrium adsorption data were analyzed by Langmuir, Freundlich, Koble–Corrigan and Dubinin–Radushkevich isotherm models. The results indicated that the Langmuir and Koble–Corrigan models provided the best correlation of the experimental data. The Elovish model was better to fit the kinetic process, which suggested that ion exchange was one of main mechanism. The effective diffusion parameter D _i values indicated that the intraparticle diffusion was not the rate-controlling step. In fixed-bed column adsorption, the effects of bed height, feed flow rate, and inlet uranium (VI) concentration were studied by assessing breakthrough curve. The Thomas, the Yan and the bed-depth/service time (BDST) models were applied to the column experimental data to determine the characteristic parameters of the column adsorption. The results were implied that CAMPS may be suitable as an adsorbent material for adsorption of uranium (VI) from an aqueous solution.     

Phenol removal from aqueous solution by adsorption and ion exchange mechanisms onto polymeric resins

The removal of phenol from aqueous solution was evaluated by using a nonfunctionalized hyper-cross-linked polymer Macronet MN200 and two ion exchange resins, Dowex XZ (strong anion exchange resin) and AuRIX 100 (weak anion exchange). Equilibrium experimental data were fitted to the Langmuir and Freundlich isotherms at different pHs. The Langmuir model describes successfully the phenol removal onto the three resins. The extent of the phenol adsorption was affected by the pH of the solution; thus, the nonfunctionalized resin reported the maximum loading adsorption under acidic conditions, where the molecular phenol form predominates. In contrast both ion exchange resins reported the maximum removal under alkaline conditions where the phenolate may be removed by a combined effect of both adsorption and ion exchange mechanisms. A theoretical model proposed in the literature was used to fit the experimental data and a double contribution was observed from the parameters obtained by the model. Kinetic experiments under different initial phenol concentrations and under the best pH conditions observed in the equilibrium experiments were performed. Two different models were used to define the controlling mechanism of the overall adsorption process: the homogeneous particle diffusion model and the shell progressive model fit the kinetic experimental data and determined the resin phase mechanism as the rate-limiting diffusion for the phenol removal. Resins charged after the kinetic experiments were further eluted by different methods. Desorption of nonfunctionalized resin was achieved by using the solution (50% v/v) of methanol/water with a recovery close to 90%. In the case of the ion exchange resins the desorption process was performed at different pHs and considering the effect of the competitive ion Cl⁻. The desorption processes were controlled by the ion exchange mechanism for Dowex XZ and AuRIX 100 resins; thus, no significant effect for the addition of Cl⁻ under acidic conditions was observed, while under alkaline conditions the total recovery increased, specially for Dowex XZ resin.     

Thermodynamic and kinetic parameters of ofloxacin adsorption from aqueous solution onto modified coal fly ash

Batch adsorption experiments were carried out for the removal of ofloxacin from aqueous solution using modified coal fly ash as adsorbent. The effects of various parameters such as contact time, initial solution concentration and temperature on the adsorption system were investigated. The optimum contact time was found to be 150 min. The adsorption isotherm data fit well with the Langmuir model, and the kinetic data fit well with the pseudo-second order and the intra-particle diffusion model. Intra-particle diffusion analysis demonstrates that ofloxacin diffuses quickly among the particles at the beginning of the adsorption process, and then the diffusion slows down and stabilizes. Thermodynamic parameters such as ΔG, ΔH, and ΔS were also calculated. The negative Gibbs free energy change and the positive enthalpy change indicated the spontaneous and endothermic nature of the adsorption, and the positive entropy change indicated that the adsorption process was aided by increased randomness.     

Investigation into adsorption mechanisms of sulfonamides onto porous adsorbents

The presence of sulfonamide antibiotics in aquatic environments poses potential ecological risks and dangers to human health. In this study, porous resins as adsorbents for the removal of two sulfonamides, sulfadiazine and sulfadimidine, from aqueous solutions were evaluated. Activated carbon F-400 was included as a comparative adsorbent. Despite the different surface properties and pore structures of the three resins, similar patterns of pH-dependent adsorption were observed, implying the importance of sulfonamide molecular forms to the adsorption process on the resins. Sulfonamide adsorption to the three resins exhibited different ionic strengths and temperature dependence consistent with sulfonamide speciation and the corresponding adsorption mechanism. Adsorption of sulfadiazine to F-400 was relatively insensitive to pH and ionic strength as micropore-filling mainly contributed to adsorption. The adsorption mechanism of sulfadiazine to the hypercrosslinked resin MN-200 was similar to that of the macroporous resin XAD-4 at lower pH values, whereas it was almost identical to the aminated resin MN-150 at higher pH. This work provided an understanding of adsorption behavior and mechanism of sulfonamide antibiotics on different adsorbents and should result in more effective applications of porous resin for antibiotics removal from industrial wastewater.