Adsorption behavior and mechanism of D113 resin for lanthanum

The sorption properties of macroporous weak acid resin （D113） for La^3＋ ion were studied by chemical analysis and IR spectra. Experimental results indicate that the D113 resin has a good adsorption ability for La^3＋ at pH = 6.0 in the HAc-NaAc medium. The statically saturated adsorption capacity is 273.3 mg/g. Separation coefficients of βLa^3＋/Ce^3＋, βLa^3＋/Gd^3＋, βLa^3＋/Er^3＋, and βLa^3＋/Y^3＋ are 2.29, 3.64, 4.27, and 0.627, respectively. The apparent activation energy of adsorption, Ea is 18.4 kJ/mol, the thermodynamics parameters AH, AS, and AG of sorption are 4.53 kJ/mol, 61.8 J/（mol·K）, -13.9 kJ/mol, respectively. The adsorption behavior of D113 for La^3＋ obeys the Freundlich isotherm. La^3＋adsorbed on resin can be eluted by 2.0 mol/L HCl quantitatively.

Sorption Behaviour and Mechanism of Lanthanum (Ⅲ) on HD-2 Resin

La(Ⅲ) was quantitatively adsorbed by macroporous weak acid resin (HD-2) in the medium of pH=6.16. The statically saturated sorption capacity is 231 mg·g -1(resin). 3.0 mol·L -1 HCl can be used as an eluant. The elution percentage is 100%. The sorption rate constant is k_ 298=3.04×10 -5 s -1. The apparent sorption activation energy of HD-2 for La(Ⅲ) is 31.2 kJ·mol -1. The sorption behavior of HD-2 for La(Ⅲ) obeys the Freundlich isotherm. The adsorption parameters of thermodynamic are ΔH=9.56 kJ·mol -1, ΔS=35.7 J·mol -1·K -1, ΔG=-1.08 kJ·mol -1, respectively.

Adsorption behavior of benzenesulfonic acid by novel weakly basic anion exchange resins

Two novel weakly basic anion exchange resins（SZ-1 and SZ-2） were prepared via the reaction of macroporous chloromethylated polystyrene-divinylbenzene（Cl-PS-DVB） beads with dicyclohexylamine and piperidine, respectively. The physicochemical structures of the resulting resins were characterized using Fourier Transform Infrared Spectroscopy and pore size distribution analysis. The adsorption behavior of SZ-1 and SZ-2 for benzenesulfonic acid（BA） was evaluated, and the common commercial weakly basic anion exchanger D301 was also employed for comparison purpose. Adsorption isotherms and influence of solution p H, temperature and coexisting competitive inorganic salts（Na2SO4and Na Cl） on adsorption behavior were investigated and the optimum desorption agent was obtained.Adsorption isotherms of BA were found to be well represented by the Langmuir model.Thermodynamic parameters involving ΔH, ΔG and ΔS were also calculated and the results indicate that adsorption is an exothermic and spontaneous process. Enhanced selectivity of BA sorption over sulfate on the two novel resins was observed by comparison with the commercial anion exchanger D301. The fact that the tested resins loaded with BA can be efficiently regenerated by Na Cl solution indicates the reversible sorption process. From a mechanistic viewpoint, this observation clearly suggests that electrostatic interaction is the predominant adsorption mechanism. Furthermore, results of column tests show that SZ-1possesses a better adsorption property than D301, which reinforces the feasibility of SZ-1for potential industrial application.

离子排斥色谱用于厌氧消化处理的水中脂肪族羧酸的分析(英文)

The analysis of seven aliphatic carboxylic acids(formic,acetic,propionic,iso-butyric,n-butyric,iso-valeric and n-valeric acid) in anaerobic digestion process waters for biogas production was examined by ion-exclusion chromatography with dilute acidic eluents(benzoic acid,perfluorobutyric acid(PFBA) and sulfuric acid) and non-suppressed conductivity/ultraviolet(UV) detection.The columns used were a styrene/divinylbenzene-based strongly acidic cation-exchange resin column(TSKgel SCX) and a polymethacrylate-based weakly acidic cation-exchange resin column(TSKgel Super IC-A/C).Good separation was performed on the TSKgel SCX in shorter retention times.For the TSKgel Super IC-A/C,peak shape of the acids was sharp and symmetrical in spite of longer retention times.In addition,the mutual separation of the acids was good except for iso-and n-butyric acids.The better separation and good detection was achieved by using the two columns(TSKgel SCX and TSKgel Super IC-A/C connected in series),lower concentrations of PFBA and sulfuric acid as eluents,non-suppressed conductivity detection and UV detection at 210 nm.This analysis was applied to anaerobic digestion process waters.The chromatograms with conductivity detection were relatively simpler compared with those of UV detection.The use of two columns with different selectivities for the aliphatic carboxylic acids and the two detection modes was effective for the determination and identification of the analytes in anaerobic digestion process waters containing complex matrices.

Adsorption behavior of ytterbium (Ⅲ) on gel-type weak acid resin

The adsorption and desorption behaviors of Yb（Ⅲ） on gel-type weak acid resin （110） were investigated. The influence of operational conditions such as contact time,initial concentration of Yb（Ⅲ）,initial pH of solution and temperature on the adsorption of Yb（Ⅲ） were also examined. The results showed that the optimal adsorption condition of 110 resin for Yb（Ⅲ） was achieved at pH=5.5 in HAc-NaAc medium. The maximum uptake capacity of Yb（Ⅲ） was 265.8 mg/g at 298 K. Yb（Ⅲ） could be eluted by using 3.0 mol/L HCl solution and the 110 resin could be regenerated and reused. The adsorption of Yb（Ⅲ） followed the Langmuir isotherm,and the correlation coefficients were evaluated. Various thermodynamic parameters such as standard enthalpy change （△H）,standard entropy change （△S） and standard free energy change （△G） were evaluated. The adsorption of Yb（III） on the 110 resin was found to be endothermic in nature. Thomas model was successfully applied to experimental data to predict the breakthrough curves and to determine the characteristics parameters of the column useful for process design. And the resin sample both before and after adsorption was described by IR spectroscopy.