3种树脂对水溶液中单宁吸附性能的比较研究

通过静态吸附实验,研究了大孔吸附树脂NG-8、胺基化大孔吸附树脂NG-9和胺基化超高交联大孔吸附树脂NDA-99对水溶液中单宁的吸附行为特性.结果表明,3种树脂对单宁的吸附均符合Langmuir等温吸附方程,树脂对单宁的吸附容量NG-9＞NG-8＞NDA-99;吸附过程符合准二级动力学方程,吸附速率常数NG-8＞NG-9＞NDA-99.树脂的孔结构与表面化学性质是影响树脂吸附性能的重要因素.     

硫辛酸在3种不同树脂上的吸附热力学和动力学研究

研究了硫辛酸在3种不同树脂上的吸附热力学和动力学。研究结果表明,硫辛酸在NG-16树脂上的吸附等温线符合Langmuir等温吸附方程,是单分子层吸附,吸附过程符合一级动力学吸附方程。硫辛酸在NDA-100和ND-90树脂上的吸附等温线符合Langmuir等温吸附方程,但并不只是单分子层吸附,对于中高浓度(大于400mg/L)的硫辛酸溶液更重要的是微孔填充作用。硫辛酸在NDA-100和ND-90树脂上的吸附过程分为大孔、中孔区的表面吸附和微孔区的微孔填充两个阶段,两个阶段都符合一级动力学吸附方程。     

多胺型阴离子交换纤维吸附铬(VI)的动力学

以聚丙烯腈纤维为原料, 采用化学改性法, 制备了多胺型阴离子交换纤维. 研究该纤维对Cr(VI)的吸附特性. 在研究的温度及浓度范围内, 该纤维对Cr(VI)吸附的平衡数据符合Langmuir和Freundlich吸附等温方程, 对Cr(VI)有较强的亲和力, 吸附反应易于进行. 重点研究了该纤维对Cr(VI)的吸附动力学特性, 分别采用Lagergren一级动力学方程、修正伪一级动力学方程、伪二级动力学方程和颗粒内扩散方程进行拟合, 计算相应的速率常数. 研究表明, 该吸附是一个快速吸附过程, 20 min即可接近吸附平衡, 吸附过程符合伪二级动力学方程, 以化学吸附为主, 该纤维能够多次反复对Cr(VI)进行吸附.     

不同基团修饰的吸附树脂对芳香两性化合物的吸附等温线研究

研究了带有不同功能基团的超高交联吸附树脂NG-10和NJ-99对水溶液中芳香两性化合物氨基苯甲酸的静态吸附性能,并与不带功能基团的吸附树脂CHA-111和XAD-4进行了比较.研究结果表明,树脂NJ-99对水溶液中氨基苯甲酸的吸附能力高于其他树脂.邻氨基苯甲酸在4种树脂上的吸附量均大于对氨基苯甲酸,主要原因是其溶解度小.吸附等温线采用经验的Freundlich方程和理论的Langmuir吸附方程来拟合,在实验所研究的浓度范围内,方程的拟合相关性均很好.     

N-乙烯吡咯烷酮/甲基丙烯酸-β-羟乙酯无规共聚物凝胶对蛋白质吸附机理的研究

用紫外分光光度法研究了牛血清白蛋白(BSA)在N-乙烯吡咯烷酮(NVP)/甲基丙烯酸-β-羟乙酯(HEMA)共聚物水凝胶上的吸附量.结果表明,BSA在凝胶上的吸附关系既可用Langmuir方程描述,又可用计量置换吸附Freundlich方程描述,且用Langmuir方程描述更为优越.研究了凝胶对BSA的吸附动力学行为,建立牛血清白蛋白的吸附动力学模型,发现用Bangharm方程对BSA吸附动力学曲线拟合程度较好,Bangharm方程可以较好地描述BSA在NVP/HEMA凝胶上的吸附动力学行为.     

花生壳吸附水中Cr6+的研究

研究了花生壳对Cr6+吸附的动力学特点,探讨了Cr6+,初始浓度、溶液的pH值及温度对Cr6+吸附效果的影响.结果表明,在Cr6+初始浓度＜100mg/L,溶液的pH值≤2.0,温度＜40℃的操作条件下,该方法具有实际应用的可能性.此吸附过程符合Lagergren准二级动力学方程,吸附等温线符合Langmuir和Freundlich模式.     

2-噻吩乙酸在三种不同树脂上的吸附热力学和动力学研究

通过静态吸附实验,研究了XAD-4,NDA-100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-100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,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.     

大孔树脂对茄尼醇吸附行为的研究

从6种大孔树脂中筛选出用于茄尼醇分离较好的树脂NKA,并进一步研究了其对茄尼醇吸附行为,结果表明,吸附等温线服从Langmuir方程和Freundlich方程,且吸附过程表现为优惠吸附.在温度为283～313K,吸附量为15～35mg/g的条件下,吸附焓变为-16.20～16.57kJ/mol,自由能变为.3.142～3.459kJ/mol,吸附熵变为-47.43～41.17J/mol.K.NKA树脂对茄尼醇吸附速率较快,吸附过程符合一级吸附动力学方程,吸附过程主要受液膜扩散控制.     

离子交换纤维吸附去除As(Ⅲ)

制备了一种新型的离子交换纤维RPFA-I,用于去除水体中亚砷酸根离子的研究.在研究的范围内,Fre-undlich型吸附等温方程能够很好地描述等温吸附平衡数据;吸附动力学数据符合Lagergren二级速度方程;pH=6.22时,吸附量达到最大;用0.1mol/L的NaOH溶液可以实现纤维的再生,再生性能优良.     

大孔螯合树脂HZ401吸附去除废水中的铅

通过静态吸附实验,研究了大孔螯合树脂HZ401吸附去除废水中铅的性能.探究了时间、树脂用量、废水中铅的初始浓度、p H、温度、转速等条件对树脂吸附铅效果的影响,分析了吸附等温线和吸附动力学过程.结果表明:在研究范围内,HZ401树脂对铅的吸附率可以达到95%以上,返洗率几乎达到100%.树脂对铅的吸附符合Langmuir和Freundlich等温吸附方程,同时符合准一级动力学Lagergren方程和准二级动力学Lagergren方程.HZ401树脂可以用于废水中痕量铅的去除.     

EQUILIBRIUM AND KINETIC ADSORPTION OF A REACTIVE BLACK KNB DYE ON POLYDIVINYLBENZENE AND STYRENE-DIVINYLBENZENE COPOLYMER RESINS

In this study, two polymeric resins with different pore sizes were synthesized to study comparative adsorption of reactive black KNB dye. Styrene-divinylbenzene copolymer resin NG-8 has an average pore size of 3.82 nm, about half of that of polydivinylbenzene resin NG-7 （6.90 nm）. NG-8 also has a surface acidity about 4 times that of NG-7, resulting in a much more negative surface of the former resin as compared to the latter at pH 6.05. Equilibrium adsorption of KNB was significantly influenced by the surface functionality of the resins, as evidenced by the observations that NG-8 adsorbed constantly less KNB than NG-7 and that the presence of CaCl2 enhanced the adsorption by both resins. The intra-particle diffusion appears to be the primary rate-limiting process. While the pores of both resins are accessible to KNB, the slower adsorption by NG-8 than by NG-7 suggests that the smaller pores of NG-8 further retard the intra-particle diffusion of KNB.     

ADSORPTION OF TANNIN ACID ONTO AN AMINATED MACROPOROUS RESIN FROM AQUEOUS SOLUTIONS

A macroporous polymeric adsorbent NG-8 was synthesized with divinylbenzene using conventional suspension polymerization technique.Its aminated product NG-9 was prepared by introducing tertiary amino groups into NG-8 for removal of tannin acid from aqueous solutions.NG-9 could be used directly without a wetting process and had higher adsorption capacity than NG-8,which might be attributed to the enhanced adsorbent-adsorbate interaction due to the tertiary amino groups on the polymeric matrix.The Langmuir equation was successfully employed to describe the adsorption process.The adsorption enthalpy change further validated the uptake of tannin acid on NG-9 to be an enhanced physical adsorption because of the Lewis acid-base interaction.In addition,adsorption kinetic studies testified that the tertiary amino groups on the polymer matrix could decrease the adsorption rate maybe for the hindrance of the tertiary amino groups and water clusters built up.     

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.     

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.     

Studies on Thermodynamic Properties of Adsorption of Theophylline by Phenolic Resin Adsorbents

In the present work, the equilibrium adsorption of theophylline was studied by phenolic resin adsor-bents: JDW-2 (made by ourselves) and Duolite S-761 within a temperature range of 303--323 K. The experi-mental results show that the Freundlich adsorption law is applicable to the adsorption of theophylline on thetwo adsorbents, the exponents n＞l indicate that they are favorable to the adsorptions; the negative values ofall the isosteric adsorption enthalpies for the theophylline indicate the exothermic process of the adsorption,while the range(10—40 kJ/mol) of their magnitudes manifests the physisorption process; other thermody-namic properties, the free energy changes and the entropy change associated with adsorption have been calcu-lated from the Gibbs adsorption equation and the Gibbs-Helmholtz equation.     

STUDY ON THE THERMODYNAMIC PROPERTIES OF ADSORPTION OF ETHYL BENZOATE AND DIETHYL PHTHALATE BY PHENOLIC RESIN ADSORBENTS

This paper presents experimental observations on the adsorption of individual solutes by a simple thermodynamic framework, and the equilibrium adsorption of ethyl benzoate and diethyl phthalate on phenolic resin adsorbent in hexane solutions within the temperature range of 293-313 K. The experimental results show that the Freundlich adsorption law is applicable to the adsorption of ethyl benzoate and diethyl phthalate on the adsorbent, since all the correlative factors R‘are larger than 0.99. The negative values of all the isosteric adsorption enthalpies for ethyl benzoate and diethyl phthalate indicate that they undergo exothermic processes, while their magnitudes (19-28 kJ/mol) manifest a hydrogen bonding sorption process. Other thermodynamic properties: the free energy changes and the entropy change associated with the adsorption have been calculated from the Gibbs adsorption equation and the Gibbs-Helmholtz equation.     

Interaction of isoniazid drug with the pristine and Ni-doped of (4, 4) armchair GaNNTs: a first principle study

In this research, the interaction of isoniazid drug (INH) with the pristine and Ni-doped Gallium nitride nanotubes (GaNNTs) is investigated by using density function theory. The adsorption energy, deformation energy, natural bond orbital (NBO), quantum parameters, molecular electrostatic potential (MEP) and thermodynamic parameters of all adsorption models are calculated from optimized structures. The values of adsorption energy, enthalpy and Gibbs free energy of all adsorption models are negative and all adsorption process are favorable in view of thermodynamic points. It is notable that Ni-doped decrease adsorption strength and it is not suitable for INH adsorption on the GaNNTs surface. The MEP, NBO and maximum amount of electronic charge ΔN results demonstrate that the negative potential are localized around adsorption position and the positive potential are localized around INH molecule. The calculated results indicate that the GaNNTs is a good candidate to making absorber and sensor for detecting INH drug.