Caiping Yao

Preparation of a novel chloromethylated polystyrene-2-amino-1,3,4-thiadiazole chelating resin and its adsorption properties and mechanism for separation and recovery of Pt(IV) from aqueous solutions

A novel chelating resin, chloromethylated polystyrene beads (PS-Cl) 2-amino-1,3,4-thiadiazole (PS-ATD), with an efficient methodology was synthesized simply by the reaction of chloromethylated polystyrene with 2-amino-1,3,4-thiadiazole. The effects of reaction parameters of PS-ATD resin (reaction solvent, reaction temperature and the molar ratio of reagents and different times) were monitored to specify the best synthesis conditions. The functional group capacity (the content of the functional group) and the percentage conversion of the functional group of PS-ATD resin prepared under optimum conditions were 3.65 mmol g−1 and 88.6%, respectively. The structure of PS-ATD resin was characterized by elemental analysis, FTIR, TGA, SEM, and energy dispersive X-ray spectroscopy (EDS). Meanwhile, the adsorption properties of the resin for Pt(IV) were investigated by batch and column experiments. The results suggested that the resin possessed much better adsorption capability for Pt(IV) than for other metal ions and the maximum saturated adsorption capacity was 222.2 mg g−1 at 308 K, estimated from the Langmuir model. Furthermore, the resin could be regenerated through the desorption of the Pt(IV) anions using the mixture of 1 wt% thiourea and 0.1 M HCl. Finally, the PS-ATD resin could provide a potential application for an efficient process of Pt(IV) recovery from aqueous solutions.

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.

Adsorption and desorption properties of D151 resin for Ce(III)

Abstract The present research is aimed at the development of D151 resin as an adsorbent that it can be used in the adsorption of Ce(III) ions. The adsorption and desorption behaviors of Ce(III) on D151 resin have been investigated by chemistry analysis. The influence of operational conditions such as contact time, initial concentration of Ce(III), initial pH of solution and temperature on the adsorption of Ce(III) had also been examined. The results show that the optimal adsorption condition of D151 for Ce(III) was achieved at pH=6.50 in HAc-NaAc medium. The maximum uptake capacity of Ce(III) was 392 mg/g resin at 298 K. The adsorption of Ce(III) followed both the Langmuir isotherm and Freundlich isotherm, and the correlation coefficients had been evaluated. Even kinetics on the adsorption of Ce(III) had been studied. The adsorption rate constant k 298 K valued was 1.3×10 −5 s −1 . The calculation data of thermodynamic parameters which Δ S 0 value of 91.34 and Δ H 0 value of 7.07 kJ/mol indicate the endothermic nature of the adsorption process. While, a decrease of Gibbs free energy (Δ G 0 ) with increasing temperature indicated the spontaneous nature of the adsorption process. Finally, Ce(III) could be eluted by using 0.5 mol/L HCl solution and the elution percentage was as high as 100%. Adsorption mechanism was also proposed for the adsorption of Ce(III) ions onto D151 resin using infrared spectroscopy technique.

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).

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...

Adsorption of Neodymium(III) on Acrylic Resin (110 Resin) from Aqueous Solutions

A feasibility of using 110 resin as an adsorbent for Nd(III) was examined with various chemical methods. Batch studies were carried out to determine the influence of operational conditions, such as initial pH of solution, temperature, contact time, and initial concentrations. The optimal conditions in terms of initial pH and equilibrium time was 6.0 (HAc–NaAc system) and 72 h, respectively. The maximum adsorption capacity was estimated to 308 mg/g at 298 K calculating from the Langmuir isotherm. Nd(III) ions could be well eluted by using 3.0 mol/L HCl solution and the absorbent could be regenerated and reused. Thermodynamic and kinetics parameters were studied, from which the adsorption process was spontaneous and the adsorption was endothermic in nature. The Thomas model based on the experimental column study data was used to predict the breakthrough curves and to determine the characteristics parameters of the column useful for process design. Moreover, the adsorption mechanism was proposed by the IR spectroscopic technique.

Removal of Co(II) from aqueous solutions by NKC-9 strong acid resin

Abstract A strong acidic ion exchange resin (NKC-9) was used as a new adsorbent material for the removal of Co(II) from aqueous solutions. The adsorption isotherm follows the Langmuir model. The maximum adsorption capacity of the resin for Co(II) is evaluated to be 361.0 mg/g by the Langmuir model. It is found that 0.5 mol/L HCl solution provides effectiveness of the desorption of Co(II) from the resin. The adsorption rate constants determined at 288, 298 and 308 K are 7.12×10 −5 , 8.51×10 −5 and 9.85×10 −5 s −1 , respectively. The apparent activation energy ( E a ) is 12.0 kJ/mol and the adsorption parameters of thermodynamic are Δ H Θ =16.1 kJ/mol, Δ S Θ =163.4 J/(mol·K), Δ G Θ 298 K =-32.6 kJ/mol, respectively. The adsorption of Co(II) on the resin is found to be endothermic in nature. Column experiments show that it is possible to remove Co(II) ions from aqueous medium dynamically by NKC-9 resin.

Adsorption of ytterbium (III) from aqueous solution by SQD–85 resin

Abstract Adsorption and desorption behavior of Yb (III) by SQD-85 resin was investigated by various chemical methods and IR spectrometry. The adsorption capacity of SQD–85 resin for Yb (III) was studied as a function of solution pH, initial concentration of Yb(III), temperature and contact time. The optimal pH for the adsorption was 5.50 in the HAc-NaAc system, and the maximum adsorption capacity was estimated to be 347.6 mg/g at 308 K. The isotherms adsorption data fit well with Langmuir model. The adsorption kinetics data are in agreement with pseudo-second-order model. Thermodynamic parameters indicate that Yb (III) adsorption by SQD–85 resin is endothermic and spontaneous in nature. Thomas model is reasonably accurate in predicting experimental column results. The dynamic desorption rate of Yb(III) can increase to 97.3% when the elution agent is 1.0 mol/L HCl. These results suggest that Yb(III) in aqueous solution can be removed and recovered by SQD–85 resin efficiently.