Methods for preparation of absorbent microspherical tannin resin

Tannin beads formed by reaction of Mimosa tannin (condensed-type tannin) with formaldehyde in nonpolar polybutenous medium were microspherical resins. Resins prepared with 37.5% tannin concentration were porous spherical resins with 139.22 m²/g of surface area (adsorption method of iodine in n-hexane, 2.1 m²/g for the dried beads by the Braunauer-Emett-Teller (BET) method) and were strong enough to withstand use on a column. The spherical resin adsorbed 3.7 mmol of Cr⁶⁺ ions per one gram dry weight of resin (by batch method), this adsorption being comparable to commercial adsorbent.     

Adsorption behavior of L-tryptophan on ion exchange resin

A batch method was applied to investigate the adsorption behavior and mechanisms of L-tryptophan (L-trp) on ion exchange resins. HZ-001 and JK006 were proved to be ideal adsorbents due to their large loading capacityand favorable selective adsorption for L-trp. Langmuir, Freundlich, and Dubinin-Radushkevich equations were appliedto simulate the experimental data to describe the adsorption process of L-trp onto HZ-001 and JK006. The maximumloading capacity (at pH 5.0, 30 °C), determined by the Langmuir and Dubinin-Radushkevich models, was close to eachother (833 mg/g vs. 874 mg/g) for HZ-001, while discrepant (833 mg/g vs. 935 mg/g) for JK006. Three diffusion-controlled kinetic models were utilized to analyze the results in order to identify the adsorption mechanism. The adsorptionkinetics of L-trp onto cation exchange resins was investigated under different experimental conditions, including initialsolution pH, temperature, initial L-trp concentration, and adsorbent dosage. Moreover, the diffusion process of L-trponto HZ-001 and JK006 was evaluated at different initial adsorbate concentrations. The thermodynamic parameters, obtained from the kinetic data, demonstrated that L-trp could be adsorbed spontaneously onto both resins.     

SCD-120阳离子交换树脂对镁离子的吸附及基础热力学性质

采用静态吸附法,研究了SCD-120阳离子交换树脂对镁离子的吸附,考察了氯化镁、溶液p H、温度、吸附时间对镁离子吸附量的影响,并对SCD-120树脂吸附镁离子的类型、速率及吸附过程的各热力学参数进行分析。结果表明,树脂用量5 g,氯化镁溶液浓度22.5%,吸附时间120 min,p H值6.1,吸附温度60℃时,树脂对镁离子的吸附容量最佳,为2.71 mmol/g。吸附动力学及热力学分析表明,SCD-120树脂对镁离子的吸附为单分子层化学吸附,符合Langmuir型吸附,吸附反应速度是由液膜扩散和颗粒扩散等多个控制步骤决定,并且吸附的过程是一个吸热、自发的熵增过程。     

SCD-120阳离子交换树脂对镁离子的吸附及基础热力学性质

采用静态吸附法,研究了SCD-120阳离子交换树脂对镁离子的吸附,考察了氯化镁、溶液p H、温度、吸附时间对镁离子吸附量的影响,并对SCD-120树脂吸附镁离子的类型、速率及吸附过程的各热力学参数进行分析。结果表明,树脂用量5 g,氯化镁溶液浓度22.5%,吸附时间120 min,p H值6.1,吸附温度60℃时,树脂对镁离子的吸附容量最佳,为2.71 mmol/g。吸附动力学及热力学分析表明,SCD-120树脂对镁离子的吸附为单分子层化学吸附,符合Langmuir型吸附,吸附反应速度是由液膜扩散和颗粒扩散等多个控制步骤决定,并且吸附的过程是一个吸热、自发的熵增过程。     

大孔离子交换树脂吸附氢化丁腈橡胶胶液中的铑和钌

研究了大孔离子交换树脂对氢化丁腈橡胶(HNBR)氯苯胶液中铑和钌贵金属的吸附能力,考察了温度对树脂吸附率的影响,并采用焚烧法回收了树脂上的金属铑和钌。结果表明,R 02、A 40、R 01树脂对铑和钌具有很好的吸附能力;当吸附温度为90℃时,A 40树脂的饱和工作吸附量(以干树脂计)为铑7.86 mg/g和钌1.09 mg/g;升高温度有助于提高树脂对铑和钌的吸附率,而且对铑的吸附效果更明显;高温焚烧回收树脂上的铑和钌,回收率可超过98.0%。     

亚胺基二乙酸树脂对镨的吸附性能及其机理

研究了镨离子在亚胺基二乙酸树脂(D401)上的吸附行为,在pH5.73时吸附最佳。测得静态饱和吸附容量为162mg·g~(-1)(树脂);用0.1～3.0mol·L~(-1)_HCl可定量洗脱;表观速率常数k_(298)=2.96×10~(-5)s~(-1);表观活化能E_a=7.18kJ·mol~()-1;等温吸附服从Freundlich经验式;吸附热力学参数△H=10.4kJ·mol~(-1),△S=45.4J·mol~(-1)·K~(-1),△G=-3.10kJ·mol~()-1;树脂功能基与镨离子的配位摩尔比为3:1;用化学和红外光谱等方法探讨了吸附机理。     

阴离子交换树脂吸附柠檬酸中的硫酸根离子

采用动态法研究阴离子交换树脂吸附柠檬酸(CA)中硫酸根离子,通过分析溶液相和树脂相中柠檬酸与SO24-的变化趋势,确立了阴离子离交树脂上柠檬酸与硫酸根离子的交换机理。研究表明,强碱性阴离子交换树脂中吸附的CA-不能被柠檬酸液中SO24-置换出;反之,弱碱性离子交换树脂所吸附的CA-可被柠檬酸液中SO24-置换出,且功能基团为树脂吸附柠檬酸液中硫酸根离子的重要因素。     

单宁改性酚醛树脂胶粘剂研究进展

在介绍可再生的绿色环保型生物质原料单宁的基础上,综述了黑荆树栲胶、落叶松栲胶以及马占相思栲胶等富含缩合单宁的生物质原料改性PF(酚醛树脂)胶粘剂的研究进展,并指出了单宁改性PF胶粘剂存在胶液黏度过大、单宁/甲醛的反应活性过高和胶液适用期过短等缺点。最后对单宁改性PF胶粘剂的研究方向进行了展望,指出利用单宁与改性木质素、玉米淀粉和生物油等生物质原料复配改性PF胶粘剂将成为重要的研究方向。     

木材防腐剂用单宁树脂的研究进展

简单介绍了单宁及木材防腐剂,综述了国内外木材防腐剂用单宁树脂的研究进展。最后对国内单宁木材防腐剂的发展前景进行了展望。     

氧化改性橡椀单宁对铜离子溶液的吸附性

以橡椀栲胶为原料,通过双氧水氧化降解改性,研究水解类橡椀单宁改性后对铜离子溶液的吸附沉淀以及pH值、金属溶液初始浓度对铜离子吸附沉淀容量的影响和规律。结果表明,氧化橡椀单宁对Cu2+的吸附平衡符合Freundlich方程。改性后吸附沉淀容量受初始浓度影响较大,初始浓度为20 mg/L时基本不发生吸附沉淀,试验最大初始浓度100 mg/L时吸附量达到39.300 mg/g。     

Adsorption of bismuth(III) by bayberry tannin immobilized on collagen fiber

The adsorption behavior of collagen fiber‐immobilized bayberry tannin towards Bi(III) at acidic pH values was investigated. The adsorption capacity of the adsorbent towards Bi(III) was 0.348 mmol g^?1 at 303 K, and increased with the rise in temperature. The adsorption isotherms of Bi(III) were in the shape of so‐called type II isotherms and could be described by an empirical equation, ln q_e = k + (1/n)C_e, which implies that chemical adsorption is predominant at lower concentrations of Bi(III) and that physical adsorption is involved at higher concentrations. The adsorption kinetics of Bi(III) on the immobilized bayberry tannin could be well described by the pseudo‐second‐order rate model, and the adsorption capacities calculated by the model were almost the same as those determined by actual measurements. The adsorbent could be regenerated by using 0.02 mol dm^?3 ethylenediaminetetraacetic acid (EDTA) solution after adsorption of Bi(III). The adsorption selectivity of the immobilized bayberry tannin towards Bi(III) in a Cu(II)–Bi(III) binary solution in acidic medium was remarkable. Therefore, it is strongly suggested that the immobilized bayberry tannin could be applied to the removal of Bi(III) from crude Cu(II) samples under proper conditions. Copyright © 2006 Society of Chemical Industry     

Adsorption behavior of metal ions by amidoxime chelating resin

The adsorption properties of poly(acrylamidoxime) chelating resin for Cu(II), Cd(II), Hg(II), Zn(II), Pb(II), Cr(III), and U(VI) are investigated by the batch technique. Based on the research results of the binding capacity effect of the pH value on sorption kinetic experiments, it is shown that this resin has higher binding capacity to uranyl ions, fast kinetics, and very good selectivity from binary metal ion mixtures with Cu(II) and Pb(II). The uranyl ion sorption strongly depends on the pH value of the solution. The highest value of 99% is at pH 5, but at pH 1 there is no retention. The adsorbed UO can be eluted by sulfuric acid and sodium carbonate. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1994–1999, 2000     

Adsorption of rubidium ion from aqueous solution by surface ion imprinted materials

A new type of rubidium ion-imprinted polymer has been synthesized by the surface-imprinting technique using methacrylic acid as the functional monomer, the rubidium ion as the template, methanol as the solvent, and silica as a carrier. Ethylene glycol dimethacrylate and 2,2-azobisisobutyronitrile were used as acrosslinker and an initiator, respectively. In addition, based on the macrocyclic effect of crown ethers, the 18-crown-6 ligand was introduced as a ligand to fix the template ions better. ...     

Mechanism of polyphenolic tannin resin hardening by hexamethylenetetramine: CP–MAS 13C-NMR

Polyflavonoid tannins have been shown by ¹³C-NMR to react with hexamethylenetetramine (hexamine) at considerably higher rates than with phenol with the formation of both benzylamine and methylene crosslinks to form hardened resins. Predominantly prodelphinidintype tannins appear to present a much higher proportion of benzylamine bridges than of methylene bridges, while in procyanidin-type tannins the proportion of the two types of crosslinks appear to be comparable. The greater the nucleophilicity of the flavonoid tannin A-rings, the greater is the proportion of benzylamine bridges which appear to form. At parity of the type of tannins, the faster the reaction with hexamine, the higher the proportion of benzylamines which appear to form. © 1995 John Wiley & Sons, Inc.     

离子交换树脂去除水中硝酸盐的研究

对比研究了国内生产的5种阴离子交换树脂(D201、D301、D407、330、717)对水中NO3-的吸附解吸情况。动态吸附饱和曲线表明,717和D407对NO3-的吸附较好,饱和吸附量分别为82.8mg/mL和54.8mg/mL,其他3种树脂效果很差;717和D407对NO3-的吸附速率也相对较快。5种树脂吸附等温线与经验公式拟合的线性相关性显著,其中330树脂符合BET经验公式,另外4种树脂符合Langmuir经验公式;再生试验表明5种树脂再生率均能达到85%以上。综合研究结果认为,强碱性苯乙烯系阴离子交换树脂717和螯合树脂D407对NO3-具有较好的吸附解吸性能,可作为去除硝酸盐的选用树脂。     

离子交换树脂铁中毒的处理

分析了离子交换树脂表面被污染的原因,介绍了污染程度的检测和树脂再生处理的方法,并讨论了污染的预防措施.     

如何更换离子交换树脂塔树脂

介绍了以机械替代人工更换离子交换树脂塔树脂的新方法。     

Inhibitory mechanism of low-carbon steel corrosion by mimosa tannin in sulphuric acid solutions

Mimosa tannin was investigated as inhibitor of low-carbon steel sulphuric acid corrosion in concentrations from 10^–5 to 10^–1 mol L^–1, at the temperature of 298 K in the solutions of pH 1, 2 and 3. The inhibitor effectiveness increases with increase in concentration. The adsorptive behaviour of mimosa tannin in solutions of pH 1 and 2 may be approximated, both by Temkin and Frumkin type isotherms, probably due to the chemisorption of tannin molecules on the metal surface. The free energies of adsorption are in the range from –35.1 to –39.5 kJ mol^–1. At pH 3, a Freundlich type isotherm is obeyed, probably due to the physisorption of ferric-tannate that forms at this pH, both on the metal surface and in the bulk electrolyte. The free energy of adsorption at pH 3 is –11.8 kJ mol^–1. The activation energy of the iron dissolution process at pH 1 was found to be 51.4 kJ mol^–1 and decreased to 48.0 kJ mol^–1 on the addition of 1.25 × 10^–2 mol L^–1 mimosa tannin. The addition of the same amount of mimosa tannin into solutions of pH 2 and 3, increased the activation energy of iron dissolution from 15.6 to 34.3 kJ mol^–1 and from 12.0 to 19.2 kJ mol^–1, respectively.     

Kinetic studies on radio-selenium uptake by ion exchange resin

Kinetic studies on the sorption of radioactive Se (IV) ion on Amberlite MB9L have been carried out under a wide range of temperature, pH, initial concentration, and resin weight. Analyses of the experimental data by two theoretical models commonly used to explain the ion exchange kinetics and shrinking core model (SCM), and homogeneous diffusion model (HDM) against exponential diffusion decay model (EDM) show a greater preference of EDM over HDM and SCM at all reaction conditions. The obtained regression coefficient values in case of HDM and SCM are in general not high enough to give a satisfactory fit for the experimental data. The estimated values for EDM parameters provides a good satisfactory fit for the yielded adsorption results as the corresponding linear regression values are high. The sorption process is found to be accompanied with fast film diffusion and slow diffusion between the reacted layer and the shrinking un-reacted core within the ion exchange resin. It also shows that ion exchange as the controlling step offers the lowest probability due to the highest obtained diffusion parameters over the normal tested reaction conditions.     

Adsorption of Ni(II) on ion exchange resin: Kinetics, equilibrium and thermodynamic studies

This article describes the ion exchange of a heavy metal Ni(II) from aqueous solutions onto a Dowex HCR-S, cationic resin. Batch adsorption studies were conducted to evaluate the effect of various parameters such as pH, resin dose, stirring speed, temperature, contact time and initial Ni(II) concentration on the removal of Ni(II). Adsorption rate increased with the increase in initial nickel concentration, stirring speed and temperature. Equilibrium adsorption isotherms were measured for the single component system, and the experimental data were analyzed by using Langmuir, Freundlich, Elovich, Temkin, Khan, Sips, Toth, Koble-Corrigan and Radke-Prausnitz isotherm equations. The Sips equation appears to fit the equilibrium data. Different models were tested for their applicability. Adsorption kinetic data were modeled using the Lagergren pseudo-first-order, Ho??s pseudo-second-order and Elovich models. It was found that Ho??s pseudo-second-order model could be used for the prediction of the system??s kinetics. Thermodynamic activation parameters such as ??G*, ??S* and ??H* of the adsorption of Ni(II) on Dowex HCR-S cationic resin were also calculated.