THE ADSORPTION BEHAVIORS OF 2,6-DICHLOROPHENOL ONTO HYPERCROSSLINKED RESINS

Experimental investigations were conducted on the adsorption characteristics of 2,6-dichlorophenol by two hypercrosslinked resin, ZH-01 and XAD-4. The static adsorption was studied. Within temperature range of 288K～313K, the equilibrium adsorption date was fitted to freundlich adsorption isotherm models to evaluate the model parameters. The enthalpies, free energy,entropy were indicative of an exothermic, a spontaneous and disorder decreasing process. The magnitudes for 2,6-dichlorophenol on ZH-01 showed a chemisorption's transitions while on XAD-4shows a physical adsorption process. The results showed that the ZH-01 adsorbents were better than the Amberlite XAD-4 for removing the 2,6-dichlorophenol in aqueous solutions.     

苯甲酰基修饰的吸附树脂对对甲苯胺的吸附机理研究

合成了用苯甲酰基修饰的新型吸附树脂ZH-03和ZH-04,同时研究了它们和AmberliteXAD-4对不同温度下水溶液中对甲苯胺的静态吸附和脱附性能,并对吸附机理进行了探讨。结果表明,经化学修饰后的树脂ZH-03和ZH-04对水溶液中对甲苯胺的吸附过程在合适温度时存在化学络合吸附作用,对吸附剂进行苯甲酰基修饰可以提高吸附剂对水溶液中对甲苯胺的吸附容量。     

ADSORPTION OF 4-METHYLANILINE IN AQUEOUS SOLUTION BY BENZOYL-CONTAINING POLYMERIC ADSORBENTS

New polymeric adsorbents (ZH-02, ZH-03) containing benzoyl group for adsorbing and removing 4-methylaniline from its aqueous solutions were prepared. Studies on the isotherms and the comparison of desorption conditions evidenced through the adsorption of 4-methylaniline in water onto ZH-02 and ZH-03, namely that there are chemisorption‘s transitions at a proper higher temperature. Mini-colunm adsorption studies of 4-methylaniline on XAD-4, ZH-02 and ZH-03 at 288 K show that the breakthrough capacities are 2.39, 2.99 and 3.19 mmol/g and the total capacities are 3.45, 3.92 and 4.35 mmol/g, respectively.     

乙酰苯胺修饰的吸附树脂对苯酚和对氯苯酚的吸附研究

通过Friedel-Crafts后交联及化学修饰反应,合成了乙酰苯胺基修饰的超高交联吸附树脂ZH-05,通过红外光谱(IR)和比表面及孔径分析(BET)对其结构进行表征.以Amberlite XAD-4树脂作为参照,通过等温吸附实验和吸附动力学实验探讨了ZH-05树脂对水溶液中苯酚和对氯苯酚的吸附性能和机理.结果表明,与XAD-4树脂相比,ZH-05树脂对苯酚和对氯苯酚均具有更佳的吸附性能.Langmuir和Freundlich方程均能较好拟合ZH-05树脂对苯酚和对氯苯酚的吸附等温线.ZH-05树脂对苯酚和对氯苯酚的吸附以焓推动的自发物理吸附过程为主,吸附过程放热;吸附符合准一级动力学吸附方程,颗粒内扩散是吸附过程的主要控制步骤.     

Adsorption behavior of phenolic compounds onto polymeric adsorbents modified with 2-carboxybenzoyl groups

<正>Two hypercrosslinked polymeric adsorbents(ZH-01 and Amberlite XAD-4 resin) were employed to remove three kinds of phenolic compounds including phenol,4-nitrophenol and 2,4-dinitrophenol from aqueous solutions.The study was focused on the static equilibrium adsorption behavior,the column dynamic adsorption and desorption profiles.The Freundlich model gave a perfect fitting to the isotherm data.The adsorbing capacities for these three compounds on ZH-01 were higher than those on Amberlite XAD-4 within the temperature range 288-318 K,which was attributed to the large micropore area and 2-carboxybenzoyl functional groups on the network of ZH-01 resin.The adsorption for phenol and 4- nitrophenol on ZH-01 was a physical adsorption process,while for 2,4-dinitrophenol it was a coexistence process of physical adsorption and chemisorption's transitions.The column test showed the advantages of ZH-01 in the dynamic adsorption processes of phenolic compounds.Being used as the desorption reagent,sodium hydroxide solution showed an excellent performance.     

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％.     

ADSORPTION OF 2,4-DICHLOROPHENOL IN AQUEOUS SOLUTION ONTO ADSORPTION RESIN MODIFIED BY N-ACETYLANILINE

A hypercrosslinked adsorption resin （ZH-05） modified by N-acetylaniline in the post crosslinking process was prepared. The adsorption properties of ZH-05 toward 2,4-dichlorophenol in comparison with granular activated carbon （GAC） and Amberlite XAD-4 were observed. The present study mainly focuses on the static equilibrium adsorption behaviors, desorption profiles and the proof of chemisorption. The results show that the Langmuir equation can give a perfect fitting to experimental data, and high temperature was favorable for adsorption of 2,4-dichlorophenol on ZH-05. A related equation was used to correlate the amount of chemisorption and the suppositionai chemisorption equilibrium concentration of adsorbate in aqueous solution. The adsorption capacities from different ranges of temperature and the static desorption experiment both reveal the same conclusion, i.e., the adsorption of 2,4-dichlorophenol from water on ZH-05 is a coexistent process of physical adsorption and chemical transition as on GAC.     

一种亲水的酚羟基修饰聚苯乙烯树脂对酚类化合物的吸附热力学

在283-323K和研究的浓度范围内,苯酚、对甲苯酚、对氯苯酚和对硝基苯酚在亲水性的酚羟基修饰聚苯乙烯树脂（AM-1）与大孔吸附树脂（Amberlite XAD-4)上平衡吸附数据符合Freundlich吸附等温方程。酚类化合物在AM-1上的吸附容量比在Amberlite XAD-4上的吸附容量增加20%以上,这主要得益于AM-1表面的酚羟基入树脂的微孔结构。在较稀的溶液中AM-1对苯酚的吸附量比AmberliteXAD-4对苯酚的吸附量增加60%,表明AM-1对苯酚有特殊的选择性。Freundlich吸附等温线、相对吸附容量以及等量吸附焓表明,四种酚在两种树脂上的吸附是物理吸附过程。对酚类化合物被两种树脂吸附的吸附焓、自由能、吸附熵也作了测试,并对吸附行为作了合理的解释。     

ADSORPTION CHARACTERISTICS OF CHLOROPHENOLS FROM AQUATIC SYSTEMS BY HYPERCROSSLINKED RESINS MODIFIED WITH BENZOYL GROUP

A hypercrosslinked polymeric adsorbent （ZH-03） for adsorbing and removing chlorophenolic compounds from their aqueous solutions was studied, including the static adsorption. The equilibrium adsorption data were fit to Freundlich adsorption isothermic models to evaluate the model parameters. Thermodynamic studies on the adsorption of chlorophenolic compounds on ZH-03 indicated that there were chemisorption transitions for 2,4,6-trichlorophenol and physical adsorption processes for 2-chlorophenol and 2,6-chlorophenol, and ZH-03 showed the homogeneous nature of the adsorbent surface. Column adsorption for chlorophenols wastewater shows the advantages of the ZH-03 adsorbent for adsorbing the following chlorophenolic compounds as 2-chlorophenol, 2,6-dichlorophenol and 2,4,6-trichlorophenol. Sodium hydroxide was used for desorpting chlorophenols from ZH-03 and showed excellent performance.     

2-噻吩乙酸在3种树脂上的吸附行为研究

通过静态吸附实验 ,研究了XAD 4、NDA 10 0和ND 90吸附树脂对水溶液中 2 噻吩乙酸的吸附热力学及动力学特性 ,结果表明 ,2 噻吩乙酸在XAD 4树脂上是单层吸附 ,符合Langmuir等温吸附方程 ,吸附过程符合准一级动力学吸附方程 .2 噻吩乙酸在NDA 10 0和ND 90树脂上的吸附也能用Langmuir等温吸附方程表示 ,但并不只是单层吸附而主要是由毛细管凝聚和微孔填充作用造成的 ,吸附过程可分为大孔和中孔区的吸附以及微孔区的吸附两个阶段 ,两个阶段都符合准一级动力学吸附方程     

新型吸附树脂对水中苯的吸附行为

研究表明,苯对人的毒性作用表现在中枢神经系统,65g／m^3的苯可引起广泛的出血导致死亡。反复暴露的低浓度苯主要对血液及造血组织产生毒性作用。根据苯吸入致白血病的流行病学研究数据,采用定量外推法计算出饮用水苯质量浓度为0．01mg/L时终身患癌的超额危险度为10^-5,因此饮用水中的苯的限值为0．01mg／L。因此,有效去除饮水中的苯具有重要的意义。     

ADSORPTION OF BENZOIC ACID AND P-NITROBENZOIC ACID ON A NEW HYPERCROSSLINKED PHENOL GROUP PST ADSORBENT

A comparison of the adsorption of benzoic acid and p-nitrobenzoic acid on the new hypercrosslinked polymeric adsorbent AM-I, with that by macroporous Amberlite XAD-4, including the equilibrium adsorption isotherms, the dynamic adsorption behaviors through column and the adsorption thermodynamics were studied. Results show that Freundlich equation gives a fitting adsorption isotherm. The specific surface of AM-l is only 67% of that of Amberlite XAD-4, but the adsorption capacities on AM-1 are much higher about 125%～166% than that on Amberlite XAD-4,which is contributed to the micropore mechanism and polarity. The negative values of the adsorption enthalpy are indicative of an exothermic process. Enthalpy and free energy changes of adsorption both manifest a physic-sorption process. The negative values of the adsorption entropy indicate that the adsorption is well consistent with the restricted mobilities and the configurations of the adsorbed benzoic acid molecules on the surface of studied adsorbents with superficial heterogeneity. Both adsorbents were used in mini-column experiments for adsorbing benzoic acid expecting to elucidate the higher breakthrough adsorption capacity of the new hypercrosslinked polymeric adsorbent AM-1 as compared with that of Amberlite XAD-4.     

ADSORPTION OF BENZOIC ACID AND P-NITROBENZOIC ACID ON A NEW HYPERCROSSLINKED PHENOL GROUP PST ADSORBENT

1.INTRODUCTIONThepolymericadsorbentAmberliteXAD-4isconsideredoneofthemostsuitablepolymericadsorbentsforremovingphenoliccompoundsfromwaterstreams[1,2]becauseitischemicallystable,notsolubleinsolventsandmoreselectiveforaromaticringsduetoitshydrophobicproperties.However,methanol,acetoneoracetonitrile,hastobeusedtoenhancethesurfacecontactbetweenadsorbentandthesolute.DavankovandTsyurupadescribedanewseriesofadsorbents[3,4].Thistechniqueyieldedpolystyrenesorbentsofunusualhypercrosslinkedstructu…     

THE ADSORPTION BEHAVIORS OF TOLUENE ON HYPERCROSSLINKED RESINS

Investigation of the adsorption characteristics of toluene on two hypercrosslinked resins. The static and the kinetic adsorption were studied. The equilibrium adsorption date was fitted to freundlich adsorption isotherm models to evaluate the model parameters. The enthalpy, free energy, entropy are indicative of an exothermic, a spontaneous and disorter decreasing process. Experimental results show that the two adsorbents are better than the Amberlite XAD-4 for removingthe toluene in aqueous solutions.     

THERMODYNAMIC STUDY OF ADSORPTION OF PHENOLIC COMPOUNDS FROM AQUEOUS SOLUTION BY A WATER-COMPATIBLE HYPERCROSSLINKED POLYMERIC ADSORBENT

Equilibrium data for the adsorption of phenolic compounds, i.e., phenol, p-cresol, p-chlorophenol and p-nitrophenol from aqueous solutions by a water-compatible hypercrosslinked polymeric adsorbent (NJ-8) within temperature range of 283-323 K were obtained and correlated with a Freundlich-type of isotherm equation, so that equilibrium constants KF and n were obtained. The capacities of equilibrium adsorption for all the four phenolic compounds on the NJ-8 from aqueous solutions are around 2 times as high as those of Amberlite XAD-4, which may be attributed to the unusual micropore structure and the partial polarity on the network. The values of the enthalpy (always negative) are indicative of an exothermic process, which manifests the adsorption of all the four phenolic compounds on the two polymeric adsorbents to be a process of physical adsorption. The negative values of free energy change show that the solute is more concentrated on the adsorbent than in the bulk solution. The absolute free energy values of adsorption for NJ-8 are always higher than those for Amberlite XAD-4, which indicates that phenolic compounds are preferentially adsorbed on NJ-8. The negative values of the adsorption entropy are consistent with the restricted mobilities of adsorbed molecules of phenolic compounds as compared with the molecules in solution. The adsorption entropy values of phenolic compounds for NJ-8 are lower than those for Amberlite XAD-4, which means the micropores of NJ-8 require more orderly arranged adsorbate.     

THE ADSORPTION BEHAVIORS OF TOLUENE ON HYPERCROSSLINKED RESINS

1. INTRODUCTION Toluene has been widely used for many industrial purposes. Owing to their toxicity and recalcitrance, the presence of toluene in the natural environment, especially in the groundwater, has been a great concern. The removal of toluene is of…     

超高交联吸附树脂吸附对硝基苯乙酮的热力学研究

比较两种超高交联聚苯乙烯吸附树脂NJ-8、AM-1与Amberlite XAD-4(以下简称XAD-4)对对硝基苯乙酮的静态吸附行为，根据吸附等温线研究了吸附热力学性质．在298～318K和研究的浓度范围内，NJ-8，AM-1、XAD-4对对硝基苯乙酮的吸附平衡数据符合Freundlich吸附等温方程．结果表明：吸附为放热过程，适当降低温度有利于吸附．计算了对硝基苯乙酮在NJ-8，AM-1、XAD-4树脂上的吸附焓变、自由能变，吸附熵变．对吸附行为作了合理的解释。     

A comparative adsorption study of β-naphthol on four polymeric adsorbents from aqueous solutions

Adsorptive removal of aromatic compounds from aqueous solutions by polymeric adsorbents has attracted many concerns in recent years. A comparative adsorption study including equilibria, kinetics and column dynamics of β-naphthol from aqueous solutions was carried out using two hypercrosslinked polymeric adsorbents (HJ-1 and TEPA) we developed and two commercial polymeric adsorbents (XAD-4 and XAD-7). The adsorption isotherms could be well described by the Freundlich equation, and the adsorption equilibrium capacities of β-naphthol followed an order of q(e)((TEPA))>q(e)((HJ-1))>q(e)((XAD-4))>q(e)((XAD-7)). The isosteric adsorption enthalpies on HJ-1 and TEPA decreased with increasing adsorption fractional loading, while a constant enthalpy was observed for XAD-4 and XAD-7, implying that HJ-1 and TEPA had a heterogeneous surface while XAD-4 and XAD-7 possessed a homogenous surface. The surface energetic heterogeneity of HJ-1 and TEPA could be well characterized by the Do's model. The adsorption kinetics were fitted by both pseudo-first-order and pseudo-second-order rate equations, and the intra-particle diffusion was found to be the rate-limiting step. The adsorption breakthrough data were well correlated by the Thomas and Clark models, and the dynamic capacities for TEPA, HJ-1, XAD-4 and XAD-7 adsorbents were calculated to be 341.7, 321.6, 268.0 and 173.8 mg/g dry resin, which were within 90% of the corresponding equilibrium capacities obtained in the batch experiments.     

超高交联吸附树脂对苯甲酸的吸附研究

用新合成的NJ－8超高交联吸附树脂吸附苯甲酸，并与Amberlite XAD-4进行比较。从静态平衡吸附行为及其热力学性质讨论吸附机理。动态穿透吸附实验进一步验证了NJ－8提高交联吸附树脂对苯甲酸的吸附能力约为Amberlite XAD-4的1.6倍。     

一种新型除酚吸附树脂的合成及性能研究

用二氯乙烷和硝基苯作溶剂,三氯化铝等作催化剂,使氯甲基化交联聚苯乙烯和苯酚在40—125℃进行Fricdel-Crafts反应。制成一种具有较高比表面和一定极性的吸附树脂。它对废水中苯酚的吸附能力是Amberlite XAD-4树脂的两倍,其动力学性能、应用范围和抗干扰能力也较好,经50次循环使用,性能无明显变化。