D-101大孔吸附树脂对黄花蒿黄酮的吸附热力学和动力学研究

通过静态吸附实验,研究了D-101大孔吸附树脂对黄花蒿黄酮的吸附热力学和动力学过程。结果表明,当温度在298~318K和在实验研究浓度范围内,D-101大孔吸附树脂对黄花蒿黄酮的吸附符合Freundlich等温吸附方程;ΔG0,吸附过程能自发进行;ΔH0,为放热过程;ΔS0,D-101大孔吸附树脂吸附黄花蒿黄酮的作用大于水的解吸过程,导致熵减。分别采用准一级动力学方程、准二级动力学方程和粒内扩散动力学模型探讨其吸附特性,研究结果表明,吸附过程符合准二级动力学方程,粒内扩散与膜扩散交互控制黄花蒿黄酮在D-101大孔吸附树脂上的吸附。     

Mg/Al-NO_3 LDH吸附诺氟沙星的热力学和动力学研究

采用平衡吸附实验,研究了诺氟沙星在自制焙烧态镁铝水滑石(Mg/Al-NO_3 LDH)上的吸附热力学和动力学行为。结果表明,在固液比1∶500、p H=5.0、吸附温度25℃、离子强度0.1 mol/L的条件下,吸附1 h对诺氟沙星(20 mg/L)的吸附过程符合Langmuir等温线方程和准二级动力学,理论平衡吸附量达到32.05 mg/g。其热力学参数ΔG0 KJ/mol,ΔH0 KJ/mol,由此推断焙烧态镁铝水滑石对诺氟沙星的吸附是自发放热反应。     

四乙烯五胺功能化纳米高分子材料对Cr(VI)与磷酸盐共存体系的吸附机理

合成了四乙烯五胺功能化纳米高分子材料(TEPA-NP),采用傅里叶变换红外光谱分析(FTIR)、有机元素分析(EA)、X射线光电子能谱分析(XPS)等手段对其进行了表征,重点考察了其对水中Cr(VI)与磷酸根离子共存时的吸附机理.结果表明,溶液p H对TEPA-NP的吸附性能影响较大.对于Cr(VI)或磷酸盐单一体系,p H 2.5时TEPA-NP的吸附效果最佳;吸附热力学均符合Langmuir模型,吸附动力学均符合准二级速率方程.TEPA-NP对Cr(VI)的饱和吸附量为123.5 mg/g;吸附过程为吸热熵增的自发过程,ΔH为16.06 k J/mol,ΔS为59.02 J/(mol K),308 K时ΔG为-2.10 k J/mol;吸附活化能为30.28 k J/mol.TEPA-NP对磷酸盐的饱和吸附量为149.2 mg/g;吸附过程为放热熵增的自发过程,ΔH为-1.74 k J/mol,ΔS为1.91J/(mol K),308 K时ΔG为-2.32 k J/mol;吸附活化能为18.85 k J/mol.当磷酸盐的共存浓度小于100 mg/L时,磷酸盐对TEPA-NP吸附Cr(VI)几乎没有影响;而当Cr(VI)的共存浓度大于5 mg/L时,Cr(VI)对TEPA-NP吸附磷酸盐的影响已较为明显,可使TEPA-NP吸附磷酸盐的饱和吸附量减小17.3%;结合红外和XPS表征可以推测TEPA-NP对Cr(VI)的吸附涉及静电与配位相互作用,而对磷酸盐以静电吸附为主;Cr(VI)与磷酸盐共存时,TEPA-NP优先吸附Cr(VI).Cr(VI)可以通过竞争取代吸附在TEPA-NP上的磷酸根,且随着Cr(VI)初始浓度增大,TEPA-NP上吸附的总磷脱附的比例增大;而磷酸根对Cr(VI)的竞争吸附较难实现.     

磁性生物炭对As(Ⅲ)的吸附行为研究

以玉米秸秆和氯化铁为原材料,通过煅烧方法制备磁性生物炭,并研究其对As(Ⅲ)的等温吸附行为及吸附热力学特征,分析不同温度(288K、298K、308K)、不同初始p H值(4、6、7、8和10)及不同离子强度(PO_4~(3-),CO_3~(2-),Cl~-,浓度分别为0.01mmol/L、0.1mmol/L、1mmol/L)对吸附的影响。结果表明,磁性生物炭对As(Ⅲ)的吸附分为快速吸附,慢速吸附和吸附平衡3个阶段。不同温度条件下,磁性生物炭对As(Ⅲ)的等温吸附过程符合Freundlich模型,吸附热力学参数ΔH0,ΔS0,ΔG0,表明磁性生物炭对As(Ⅲ)的吸附是自发进行,吸附过程为吸热过程,温度升高,有利于磁性生物炭对As(Ⅲ)的吸附;在p H=7时,磁性生物炭对As(Ⅲ)的吸附效果最佳;吸附量随离子强度的增加而减小。     

D151阳离子交换树脂吸附Zwittermicin A的热力学

采用静态吸附法研究了D151阳离子交换树脂对Zwittermicin A的吸附过程的热力学性质。结果表明,在温度288、298和318 K和研究的浓度范围内,Zwittermicin A在D151阳离子交换树脂上吸附等温线均符合Freundlich吸附等温线方程。热力学参数表明,吸附过程是自发的、放热的优惠型吸附。     

松香基羧基化聚合物微球对Pb~(2+)的吸附研究

采用静态吸附法研究了松香基羧基化聚合物微球对Pb~(2+)的吸附性能。实验结果表明,在p H=6.0,固液比分别为0.5g/L和3g/L,初始浓度为100mg/L,293K条件下,松香基羧基化聚合物微球对Pb~(2+)的最大吸附量分别为15.28mg/g和10.73mg/g。吸附动力学研究表明,该吸附过程符合伪二级吸附动力学方程。吸附热力学研究表明,该吸附过程符合Langmuir等温吸附模型,ΔG0,ΔS0,ΔH0,表明该吸附过程是自发的放热过程。脱附再生实验表明,经过5次重复再生,其吸附量下降了29%,微球具有重复利用的潜质。XPS测试表明Pb~(2+)吸附在微球的表面上。     

聚(苯乙烯-二乙烯苯)树脂对聚乙二醇的吸附研究

制备了聚(苯乙烯-二乙烯苯)树脂NDA-150,并将其应用于聚乙二醇(PEG)模拟废水处理。研究了投加量、p H值、温度及时间对PEG去除效果的影响。实验结果表明,最佳投加量为0.4g/L,此时吸附量Qe为35mg/g;初始p H值对吸附过程的影响可忽略不计,最佳温度为293K,吸附等温线可使用Freundlich方程很好地拟合。PEG在NDA-150树脂上吸附的ΔH,ΔG以及ΔS的计算结果表明,吸附过程是自发的放热过程,且熵是增加的。整个吸附过程约在24h左右达到平衡,吸附动力学数据符合拟二级动力学方程。     

高容量咪唑型螯合树脂的制备及其对Cd(Ⅱ)和Zn(Ⅱ)的吸附性能

以氯甲基化交联聚苯乙烯树脂(CMCPS)为载体和大分子引发剂,1-乙烯基咪唑(VIM)为单体,溴化亚铜/2,2'-联吡啶为催化剂体系,采用表面引发原子转移自由基聚合技术(SI-ATRP),将1-乙烯基咪唑接枝到CMCPS树脂表面,制得新型咪唑型螯合树脂(VIM-CMCPS),并采用X射线光电子能谱、元素分析和扫描电镜对其进行表征。考察了该螯合树脂对Cd2+和Zn2+的吸附性能、动力学和热力学参数。该螯合树脂表面VIM接枝密度达1.008 mg/m2。结果表明,该树脂对Cd2+和Zn2+的吸附量随溶液初始浓度和温度的升高而增加,当p H值分别为3.6和2.4时,对Cd2+和Zn2+的吸附效果最佳,树脂的静态饱和吸附容量分别为653.1 mg/g和793.3 mg/g,Langmuir和Freundlich方程均呈现良好的拟合度。热力学平衡方程计算得ΔG0,ΔH=24.47 k J/mol,ΔS0,表明该吸附过程是自发、吸热、熵增加的过程。动力学研究表明,该过程符合准二级动力学模型。     

聚丙烯酰胺树脂的制备及其对2,4-二氯苯氧乙酸的吸附性能研究

以氯甲基化交联聚苯乙烯树脂(CMCPS)为载体和大分子引发剂,溴化亚铜/2,2’-联吡啶为催化剂体系,采用了表面引发原子转移自由基聚合技术(SI-ATRP),将丙烯酰胺接枝到CMCPS树脂表面,制得了新型聚丙烯酰胺树脂(PAM-CMCPS),并且用元素分析、扫描电镜和红外光谱对其进行了表征。考察了此树脂对2,4-二氯苯氧乙酸的吸附性能、动力学和热力学参数。结果表明,此树脂对2,4-二氯苯氧乙酸的吸附量随溶液初始浓度和温度的升高而增加,当初始浓度为8 mmol/L时吸附效果最佳,树脂的静态饱和吸附容量为111.0 mg/g,Langmuir和Freundlich方程都呈现良好的拟合度。热力学平衡方程计算得ΔG<0,ΔH=268.2 k J/mol,ΔS>0,表明此吸附过程是一个自发、吸热、熵增加的过程。动力学研究表明,准二级动力学方程能较好拟合动力学实验结果,该过程符合准二级动力学模型。此PAM-CMCPS树脂应用于柑橘样品中2,4-二氯苯氧乙酸的吸附,取得了较满意的结果。     

微波改性膨润土对水中PFOS的吸附热力学和动力学研究

以十六烷基三甲基溴化铵(CTMAB)微波改性膨润土(CTMAB-膨润土)作为吸附剂。在初始浓度为50~100mg/L,温度为288~308K时,研究了CTMAB-膨润土对PFOS的吸附热力学和动力学规律。结果表明,吸附反应2h后,CTMAB-膨润土对PFOS吸附量达到平衡吸附量的80%,随后吸附速率逐渐变缓并在吸附反应进行约4h后达到平衡;PFOS在CTMAB-膨润土上的吸附过程符合伪二级动力学方程和Langmuir等温吸附模型。通过热力学分析发现?H~00、?G~00、?S~00、E_a=26.7k J/mol,表明PFOS在CTMAB-膨润土上的吸附属于易于自发进行的物理吸附过程,吸附过程吸热,但吸附热较小,温度对吸附过程的影响较小。吸附饱和的CTMAB-膨润土可在NaOH溶液中脱附再生,经4次脱附后,PFOS的吸附量为140.6mg/g,具有良好的再生使用性,可以循环使用。     

锆、铁水合氧化物对磷酸根的吸附

将氯氧化锆、三氯化铁分别与双氧水和氨水反应,生成锆、铁水合金属氧化物。用这两种氧化物作为吸附剂对水中的磷进行吸附。讨论了吸附过程对吸附容量的影响因素(温度、pH、时间)及除磷机理。实验结果表明,在低的pH值下,吸附容量最大;该吸附过程主要是以离子交换反应进行的吸热过程;可以用Freundlich方程表示静态吸附的吸附等温线;吸附动力学符合一级反应方程。     

Non-destructive radioanalytical technique in characterization of anion exchangers Amberlite IRN78 and Indion H-IP

The present study deals with characterization of industrial grade anion exchange resins Amberlite IRN78 and Indion H-IP for which non-destructive radiotracer technique using ¹³¹I and ⁸²Br was used. The radioisotopes were used to trace the kinetics of iodide and bromide ion-isotopic exchange reactions taking place in the two resins. It was observed that under identical experimental conditions of 40.0 °C, 1.000 g of ion exchange resins and 0.003 M labeled iodide ion solution for iodide ion-isotopic exchange reaction, the values of specific reaction rate (min^?1), amount of iodide ion exchanged (mmol), initial rate of iodide ion exchange (mmol min^?1) and log K _d were 0.285, 0.544, 0.155 and 12.6 respectively for Amberlite IRN78 resin, which was higher than 0.093, 0.315, 0.029 and 4.9 respectively as that obtained by using Indion H-IP resins. Also at a constant temperature of 40.0 °C, as the concentration of labeled iodide ion solution increases 0.001–0.004 M, the percentage of iodide ions exchanged increases from 68.10 to 74.00 % for Amberlite IRN78 resin, which was higher than the increase of 40.20–42.80 % as observed for Indion H-IP resins. The identical trend was observed for the two resins during bromide ion-isotopic exchange reaction. The overall results indicate that that under identical experimental conditions Amberlite IRN78 resins shows superior performance over Indion H-IP resins.     

Adsorption of Promethazine hydrochloride with KSF Montmorillonite

Adsorption of Promethazine hydrochloride (PHCl) onto KSF Montmorillonite from aqueous solution has been investigated. Experiments were conducted at various pH values, ionic backgrounds and solution temperatures. The pseudo-second-order equation successfully predicted the adsorption among the tried kinetics models (pseudo-first-order, pseudo-second-order and intraparticle diffusion). Langmuir, Freundlich and DR adsorption models were used to describe equilibrium isotherms and the isotherm constants were obtained. The increase in solution temperature caused a decrease in the adsorption capacity values found from Freundlich and DR isotherm. The adsorption type can be explained by combined ion exchange and physisorption. Thermodynamic parameters of adsorption of Promethazine hydrochloride (PHCl) onto KSF were also evaluated. The surface morphologies of KSF and PHCl loaded KSF were examined using a scanning electron microscope (SEM). FTIR measurements of samples were also conducted.     

Determination of lead separated selectively with ion exchange method from solution onto BCW in Sirnak, East Anatolia of Turkey

There are approximately 82 million of tons asphaltites reserves in ?irnak, East Anatolia of Turkey. The present study was investigated to employ ashes of S?rnak BCW (burned coal waste) as an ion exchange in removal of important toxic metal, Lead (Pb), in high yields by adsorption. The ion exchange characteristics of lead onto BCW from aqueous solution were investigated with respect to the changes in pH of solution, adsorbent dosage, initial metal ion concentration, contact time and temperature of solution. For the adsorption of lead, the Langmuir isotherm model fitted to equilibrium data better than the Freundlich isotherm model. Thermodynamic functions, the change of free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) of adsorption were also calculated for lead. These parameters showed that the adsorption was feasible, spontaneous and exothermic at 293–333 K. Experimental data were also evaluated in terms of kinetic characteristics of adsorption. The batch kinetic data were correlated to the pseudo-first order and pseudo-second order models. The data fitted better to the pseudo-second order equation. The activation energy of systems was determined. Experimental data have shown that BCW that was used in unmodified form; as low cost, readily available ion exchange; can be used for removal of lead from industrial waste waters. Analysis was determined using Flame Atomic Absorption Spectrometry (FAAS).     

Film-Pore Diffusion Control for the Batch Sorption of Cadmium Ions from Effluent onto Bone Char

The sorption equilibrium and kinetics of cadmium ions from aqueous solution onto bone char have been studied. Equilibrium isotherms for the sorption system were correlated by Langmuir and bi-Langmuir equations. The application of the bi-Langmuir equation was developed because the mechanistic analysis in this research indicated that cadmium removal occurs ion exchange and physical adsorption onto different surface sites. The bi-Langmuir equation provides a better fit to the experimental data. In addition, the removal rates of cadmium ions based on the Langmuir models have been investigated. The effective diffusivity was calculated using the effects of initial metal ion concentration and bone char mass. Two mass-transport models based on film-pore diffusion control have been applied to analyze the concentration decay curves. The film and pore diffusion coefficients using an analytical equation are equal to 1.26x10(-3) cm/s and 5.06x10(-7) cm(2)/s, respectively. The pore diffusion coefficient obtained from the numerical method is 4.89x10(-7) cm(2)/s. A sensitivity analysis showed that the film-pore diffusion model and constant effective diffusivity could be used to describe the mass-transport mechanism of the sorption system with a high degree of correlation. Copyright 2001 Academic Press.     

Adsorption of fluoride, phosphate, and arsenate ions on a new type of ion exchange fiber

A new type of ion exchange fiber for the removal of fluoride, phosphate, and arsenate ions has been developed. A batch adsorption technique for investigating adsorption kinetic and equilibrium parameters and determining pH adsorption edges is applied. It is shown that the adsorption properties of the ion exchange fiber for fluoride, phosphate, and arsenate ions depend on the pH value and anion concentration. The adsorption of arsenate on the sorbent reaches a maximum of 97.9% in the pH value range of 3.5 to 7.0. The adsorption percentage of phosphate is more than 99% in the pH range of 3.0 to 5.5. The adsorption of fluoride on the ion exchange fiber is found to be 90.4% at pH 3.0. The Freundlich model can describe the adsorption equilibrium data of fluoride, arsenate, and phosphate anions. The sorption of the three anions on the ion exchange fiber is a rapid process, and the adsorption kinetic data can be simulated very well by the pseudo-second-order rate equation. The column performance is carried out to assess the applicability of the ion exchange fiber for the removal of fluoride, phosphate, and arsenate ions from synthetic wastewaters with satisfactory removal efficiency. The desorption experiment shows that fluoride ion sorbed by the fiber column can be quantitatively desorbed with 5 mL of 0.50 mol/L NaOH at elution rate of 1 mL/min, and 30 mL of NaOH is necessary for the quantitative recovery of phosphate and arsenate ions.     

63Ni在泥煤-水体系中的吸附动力学

应用同位素示踪技术,简要地研究了63Ni在泥煤中的静态吸附行为。结果表明,5 min后泥煤对63Ni的吸附率可达69%,60min后达到吸附平衡;第1吸附阶段内镍吸附量随时间的延长而增加,不易解吸;从泥煤-水液固体系中泥煤的电离平衡和镍离子-氢离子之间离子交换平衡,以及物料平衡关系推导出泥煤平衡时63Ni的吸附量和氢离子的浓度、平衡时镍离子的浓度有关。溶液的pH值对镍的吸附和解吸有很大影响,随着溶液pH值增大,63Ni由水分室向泥煤分室转移的速率常数也逐渐增大,而由泥煤分室向水分室转移的速率常数逐渐减小,二者比值逐渐增大,pH=4.624 6时,2种可逆传递速率常数相等,为2.51。即适宜pH值范围内的pH值升高吸附量增大,低pH值不利于吸附。63Ni在泥煤-水体系中的动态变化可用封闭二分室进行描述,经拟合后的理论值与实验数据点具有较好的一致性。     

金的离子交换与吸附化学 II: 大孔交联聚甲基丙烯酸酯MET-802对AuCl4^-的吸附及解吸动力学

研究了大孔交联聚甲基丙烯酸酯树脂(相当于Amberlite-XAD-7)吸附和解吸AuCl4^-的动力学. 结果表明, 两种过程均由液膜扩散转向粒内扩散主控. HCl浓度对吸附AuCl4^-过程影响甚微, 研究了HCl-硫脲为解吸剂时的动力学, 表明液膜扩散常数R和粒内扩散常数B对树脂半径r0的关系服从Boyd方程.     

LiTi2(PO4)3的Na/Li离子交换特征

锂离子传导材料LiTi₂(PO₄)₃能在LiCl水溶液中高选择性地与Na⁺进行离子交换. 研究了NaCl 溶液中LiTi₂(PO₄)₃上的Na/Li离子交换反应, 实验结果表明, 升高温度能显著提高LiTi₂(PO₄)₃上的Na/Li交换反应速率, 其离子交换动力学规律可近似由JMAK(Johnson-Mehl-Aurami-Kalmogorav)方程描述. 对LiTi₂(PO₄)₃在水和NaCl溶液中的溶解行为的研究结果表明, 升高温度能加快其在水中的溶解速率, pH值过大或过小及离子交换都会加剧LiTi₂(PO₄)₃的溶解.     

Selectivity study of strongly acidic cation exchange resin Amberlite IR-120

The thermodynamic measurements was carried out to study the selectivity of cation exchange resin Amberlite IR-120 in protonated form with respect to Mg²⁺, Ca²⁺, Sr²⁺ and Ba²⁺ ions in solution. The equilibrium constant K was calculated using the activity coefficients of ions in solution as well as in the resin. The K values calculated for the reacting systems increase with temperature that suggests the endothermic exchange reactions with estimated enthalpy values of 38.8, 20.6, 8.45, and 7.24 kJ mol⁻¹, respectively. On the basis of calculated parameters, the selectivity of ion exchange resin with respect to various bivalent ions in the solution was predicted. The method used in our experimental work provides a basis for characterization of ion exchange resins, which can be promising materials for efficient separation of ions from industrial waste effluents.