Chunhua Xiong

Evaluation of D113 cation exchange resin for the removal of Eu(III) from aqueous solution

Batch adsorption experiments were conducted for the adsorption of Eu(III) ions from aqueous solution by D113 resin. The results indicated that D113 resin could adsorb Eu(III) ion effectively from aqueous solution. The adsorption was strongly dependent on pH of the medium with enhanced adsorption as the pH turned from 3.50 to 7.00 and the optimal adsorption condition was in HAc-NaAc medium with pH value of 6.50. The maximum uptake capacity of Eu(III) ions was 290.9 mg/g D113 at 298 K, at an initial pH value of 6.50. The overall adsorption process was best described by Lagergren-first-order kinetics. When Freundlich and Langmuir isotherms were tested, the latter had a better fit with the experimental data. The thermodynamic parameters such as free energy (?G) which were all negative, indicated that the adsorption of Eu(III) ions onto D113 resin was spontaneous and the positive value of enthalpy (?H) showed that the adsorption was endothermic in nature. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design. Furthermore, Eu(III) could be eluted by using 3.0 mol/L HCl solution and the D113 resin could be regenerated and reused.

Enhanced adsorption behavior of Nd(III) onto D113-III resin from aqueous solution

Abstract An enhanced adsorption and desorption procedure of Nd(III) onto D113-III resin were prepared with various chemical methods. Batch studies were carried out with various pH, contact time, temperature and initial concentrations, and then column studies were conducted. The results showed that the optimal adsorption condition was at pH value of 6.90. The process was fast initially and arrived equilibrium within 60 h. The resin exhibited a high Nd(III) uptake as 232.56 mg/g at 298 K. The adsorption data fitted well with pseudo-second-order kinetic model. Thermodynamic parameters were studied, which indicated that the adsorption process was spontaneous and endothermic. Thomas model was delineated here to predict the breakthrough curves based on the experimental column study data. In the elution test, 1 mol/L HCl solution could achieve a satisfactory elution rate, which indicated that D113-III resin could be regenerated and reused. Finally, the IR spectroscopic technique was undertaken, and a novel adsorption mechanism was proposed.

Effect of pH on sorption for RE(III) and sorption behaviors of Sm(III) by D152 resin

Abstract The pH dependent sorption of rare earth ions (La(III), Ce(III), Pr(III), Nd(III), Y(III), Sm(III), Eu(III), Gd(III), Tb(III), Dy(III), Ho(III), Er(III), Lu(III), and Yb(III)) from HAC-NaAC buffer solution at 298 K by D152 resin containing -COOH function groups were presented. The sorption behaviors of D152 resin for Sm(III) were discussed as an example. The effects of operational conditions such as pH, temperature, and contact time were studied. The statically saturated sorption capacity was 510 mg/g resin at pH 6.70 in HAc-NaAc medium at 298 K. The sorption behaviors obeyed the Freundlich isotherm. The capacity value for column study was obtained by graphical integration as 495 mg/g resin. Thomas model was applied to experimental data to predict the breakthrough curve and to determine the characteristic parameters of the column useful for process design.

Adsorption of erbium(III) on D113-III resin from aqueous solutions: batch and column studies

Abstract The adsorption and desorption behaviors of Er(III) ion on D113-III resin were investigated. Batch adsorption studies were carried out with various Er(III) ion concentrations, pH, contact time and temperature, indicating that D113-III resin could adsorb Er(III) ion effectively from aqueous solution. The loading of Er(III) ion onto D113-III resin increased with increasing the initial concentration. The adsorption was strongly dependent on pH of the medium with enhanced adsorption as the pH turned from 3.45 to 6.75. In the batch system, the D113-III resin exhibited the highest Er(III) ion uptake as 250 mg/g at 298 K, at an initial pH value of 6.04, calculated from the Langmuir isotherm model. The adsorption kinetics was in agreement with Lagergren-first-order kinetics among the Lagergren-first-order model, pseudo-second-order model, liquid film diffusion model and intraparticle diffusion model. The adsorption data gave good fits with Langmuir isotherms. The thermodynamic parameters such as Δ G , which were all negative, indicated that the adsorption of Er(III) ion onto D113-III resin was spontaneous and the positive value of Δ H showed that the adsorption was endothermic in nature. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design. Er(III) ion could be eluted by using the 4.0 mol/L HCl solution. The characterization of both before and after adsorption of Er(III) ion on D113-III resin was undertaken with IR spectroscopic technique. Moreover, the surface characterization of D113-III resin was described by scanning electron micrographs (SEM).

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

Abstract 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 (ΔH), standard entropy change (ΔS) and standard free energy change (ΔG) 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.

Optimization of conditions for Cu(II) adsorption on 110 resin from aqueous solutions using response surface methodology and its mechanism study

Abstract An experimental study on removal of Cu(II) from aqueous solutions using 110 resins was carried out in a batch system. The effects of various operating parameters such as temperature, pH, and initial concentration were analyzed using response surface methodology (RSM). The results showed that the optimal adsorption condition of 110 resin for Cu(II) were 35°C, pH = 5.28, and initial Cu(II) concentration of 0.34 mg/mL. At optimum adsorption conditions, the adsorption capacity of Cu(II) was 336 mg/g, well in close agreement with the predicted value by the model. The apparent activation energy E a and adsorption rate constant k 298K values were 11.80 kJ/mol and 3.92 × 10−5 s−1, respectively. The adsorption isotherms data fitted well with the Langmuir model. Thermodynamic parameters (ΔG, ΔS, ΔH) suggested that the adsorption process was endothermic and spontaneous in nature. Desorption study revealed that Cu(II) can be eluted using 1.0 mol/L HCl solution, which indicated that Cu(II) in aqueous solution...

Study on the adsorption of Pb2+ from aqueous solution by D113-III resin

Abstract The adsorption and desorption behaviors of Pb2+ on D113-III resin were investigated with various chemical methods. The influence of operational conditions such as contact time, initial concentration, initial pH of solution, and temperature on the adsorption of Pb2+ has also been examined. The results show that the maximum uptake capacity of Pb2+ is 476.2 mg/g on D113-III resin at 298 K at pH = 4.5 in HAc–NaAc medium. The adsorption of Pb2+ fitted the Langmuir isotherm better than the Freundlich isotherm. And kinetics on the adsorption of Pb2+ has been studied. The apparent activation energy E a and adsorption rate constant k 298 values are 5.22 kJ/mol and 5.82 × 10−5 s−1, respectively. The data of thermodynamic parameters whose ΔS value is 0.255 kJ/mol K and ΔH value is 45.29 kJ/mol indicate the endothermic nature of the adsorption process. And the negative value of ΔG showed that the adsorption of Pb2+ ions onto D113-III resin was spontaneous. The Thomas model was applied to experimental data ob...

Study on sorption of D155 resin for gadolinium

The sorption behavior and mechanism of a Macroporous weak acid resin, D155 resin,for Gd(III) were investigated. The statically saturated sorption capacity is 283 mg/g resin at 298 K in HAc-NaAc medium. The Gd(III) adsorbed on macroporous weak acid resin, D155 resin,could be reductively eluted with the mixed solution of HCl and NaCl, and the elution percentage was as high as 100%. The resin could be regenerated and reused without remarkable decrease in sorption capacity. The apparent sorption rate constant was k298=1.98 × 10−5 s−1. The apparent activation energy was Ea=2.78 kJ/mol. The sorption behavior of D155 resin for Gd(III) obeyed the Langmuir isotherm. The thermodynamic sorption parameters were ΔH=33.0 kJ/mol, ΔS=192 J/mol/K, and ΔG298=-24.3 kJ/mol. The sorption mechanism of D155 resin for Gd(III) was examined by using chemical method and IR spectrometry. The coordination compound was formed between oxygen atoms in the functional group of D155 resin and Gd (III).