• Journal of the Korean Chemical Society
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• v.28 no.6
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• pp.403-411
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• 1984

Amberlite XAD-7 and XAD-4 resins impregnated with DXHQ (5,7-dihalo-8-hydroxyquinoline) were prepared for the adsorption, separation and recovery of heavy metal ions from aqueous solutions. The characteristics of the impregnated resins, DXHQ (X : Cl, Br, I)-XAD were studied to find out the proper pairs of resin and DXHQ for the adsorption of metal ions. The increasing order of the impregnated amount of DXHQ onto XAD-7 resin was as follows: DCHQ < DBHQ < DIHQ. It was observed from the plot of log $K_d$ vs. pH that the optimum pH range for the adsorption of DIHQ onto XAD-4 resin was from 3.0 to 7.0. The stabilities of the DXHQ-XAD resins were investigated by measuring the amount of DXHQ remained on the XAD resin after shaking the DXHQ-XAD resins in various solutions of pH ranging from 2 to 12 and hydrochloric acid solutions. The impregnated resins were considerably stable in both acidic and neutral solutions. The amount of DIHQ leached from DIHQ-XAD-4 resin by eluting with various HCl solutions (1 ∼ 5M) was negligible, but in the case of XAD-7 resin it increases as the concentration of HCl solution increases. The optimum pH ranges, absorption mole ratio (M : DXHQ) and adsorption capacities (mmol metal per gram of resin) for the adsorption of metal ions onto the DXHQ-XAD resins were determined respectively. The stability of metal ion absorbed by the DXHQ-XAD resins was observed as the following order: M-DCHQ-XAD-7 < M-DBHQ-XAD-7 < M-DIHQ-XAD-7. The adsorbed metal ions were quantitatively recovered by eluting with HCl (0.5 ∼ 5M) and DXHQ-XAD resins could be reused over 5 times without re-impregnation of DXHQ.

• Journal of the Korean Chemical Society
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• v.27 no.5
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• pp.353-360
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• 1983

The adsorption behavior of 8-hydroxyquinoline (8HQ) on Amberlite XAD-4 and-7 resins was investigated by measuring its distribution coefficients under various experimental conditions, such as shaking time, pH and concentration of methanol in the medium. The application of 8HQ-impregnated-XAD resins for the absorption and separation of metal ions was studied. The maximum adsorption of 8HQ on XAD resins was observed in the 30% methanol solution having pH range from 6.0 to 9.0. The impregnation capacities of XAD resins for 8HQ were 3.81${\times}$10-2mmol, 8HQ/g, XAD-4 resins and 2.60${\times}$10-2mmol, 8HQ/g, XAD-7 resin, respectively. The 8HQ-impregnated-XAD resins were stable in pH range from 6.0 to 10.0 and the amount of 8HQ leached from XAD-4 resin by eluting with hydrochloric acid(above 5M) was negligible. The optimum pH range for the adsorption of metal ions on 8HQ-impregnated XAD resin was also 6.0 to 10.0, and the adsorption mole ratio of metal ion to 8HQ were 1 : 2 for Cu(II), Cd(II) and Ni(II), and 1 : 3 for Fe(III) at the above pH range. It was found that the absorbed metal ions on 8HQ-impregnated-XAD resins were recovered quantitatively with 5M HCl and 8HQ-impregnated-XAD-4 resin could be reusable over 5 times without decrease in its impregnation capacity.

• Analytical Science and Technology
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• v.6 no.5
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• pp.489-499
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• 1993

Some sorption behaviors of U(VI) ion on Arsenazo I-XAD-2 chelating resin were investigated. This chelating resin was synthesized by the diazonium coupling of Amberlite XAD-2 resin with Arsenzo I chelating reagent and characterized by elementary analysis method and IR spectrometry. The optimum conditions for the sorption of U(VI) ion were examined with respect to pH, U(VI) ion concentration and shaking time. Total sorption capacity of this chelating resin on U(VI) ion was 0.39mmol U(VI)/g resin in the pH range of 4.0~4.5. This chelating resin was showed increased sorption capacity on the increased pH value. It was confirmed that sorption mechanism of U(VI) ion on the Arsenazo I-XAD-2 chelating resin was competition reacting between U(VI) ion and $H^+$ ion. Breakthrough volume and overall capacity of U(VI) ion measured by column were was 600 ml and 0.38 mmol U(VI)/g resin, respectively. The desorption of U(VI) ion was showed recovery of 90~96% using 3M $HNO_3$ and 3M $Na_2CO_3$ as a desorption solution. The separation and concentration of U(VI) ion from natural water and sea water was performed successfully by Arsenazo I-XAD-2 chelating resin.

• Journal of the Korean Chemical Society
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• v.31 no.4
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• pp.308-314
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• 1987

The adsorption behavior of some chelating agents on the Amberlite XAD-7 resin was studied to obtain the optimum conditions for the preparation of chelating agent-XAD-7 resins. The chosen chelating agents are cupferron (CP), diphenylcarbazone (DPC), salicylaldoxime (SAO), thiosalicylic acid (TSA), and dimethylglyoxime (DMG), which have been well known chelating agents to Cu(Ⅱ) and Ni (Ⅱ) ions. Among the chelating agent-XAD-7 resins, SAO-XAD-7 and DMG-XAD-7 resins were evaluated as appropriate impregnated resins by investigating their stabilities in the wide pH range and high abilities to adsorb Cu(Ⅱ) and Ni(Ⅱ) ions. The selective adsorption of Cu(Ⅱ) from Ni(Ⅱ) was possible by changing pH condition by SAO-XAD-7 resin. The adsorption capacities of SAO-XAD-7 and DMG-XAD-7 for Cu(Ⅱ) were $7{\times}10^{-3}mmol$ Cu(Ⅱ) per gram of resin and $2{\times}10^{-3}mmol$ Cu(Ⅱ) per gram of resin, respectively. The quantitative recovery of Cu(Ⅱ) adsorbed by the resin was demonstrated. The adsorption behavior of Cu(Ⅱ) and Ni(Ⅱ) by the single and mixed bed of chelating agent-XAD-7 resin was discussed.

• Analytical Science and Technology
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• v.8 no.3
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• pp.397-404
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• 1995

Three Arsenazo I-XAD Chelating resins, with different surface areas and pore sizes were synthesized and characterized. The total sorption capacities of these chelating resins for Cu(II) at pH 5.0 by batch method decreased as follows, Arsenazo I-XAD-16(0.59mmol/g)>Arsenazo I-XAD-4(0.56mmol/g)>Arsenazo I-XAD-2(0.38mmol/g). The sorption and desorption properties of Arsenazo I-XAD-16 chelating resins for U(VI), Th(IV), Hf(IV), Zr(IV), Ni(II), Mn(II), Cd(II). and Cu(II) were studied by both batch and elution method. The Arsenazo I-XAD-16 chelating resin was successfully applied to the separation and concentration of trace U(VI) and Th(IV) in sea and waste waters.

• Journal of Environmental Science International
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• v.5 no.3
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• pp.369-376
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• 1996

The adsorption of the anionic surfactants, sodium lauryl sulfate (SLS) and sodium dodecylbenzene sulfonate (SDBS) anion surfactants form aqueous solutions with nonionic resins, Amberlite XAD-2, XAD-4 and XAD-7 at temperatures in 15~45$^{\circ}C$ range was studied. Several adsorption isotherm models were used to fit the experimental data, The best results were obtained with the Redlich-Peterson equation and the Freundlich model provided remarkably good fits. For a particular resin at a particular temperature, SDBS was more extensively adsorbed than SLS. The highest adsorption were obtained with XAD-4 resin and the specific surface area of the resins plays a major role in adsorption of the surfactants. Estimations of the isosteric heat of adsorption were indicative of an exothermic process, and their magnitudes manifested a physisorption process.

• Journal of the Korean Wood Science and Technology
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• v.44 no.3
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• pp.389-397
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• 2016

In this study, ethanol was produced from a biomass hydrolysate that had been treated by electrodialysis (ED) and Amberlite XAD resin to remove fermentation inhibitors. Most of the acetic acid (95.6%) was removed during the ED process. Non-ionizable compounds such as total phenolic compounds, 5-hydroxymethyl furfural, and furfural were effectively removed by the XAD resin treatment. Ethanol production was improved when the ED-treated hydrolysate was treated with XAD-4 resin for a short reaction time. The highest ethanol production from ED-treated hydrolysate was $6.16g/{\ell}$ (after 72 h of fermentation) when the treatment with XAD-4 resin was for 5 min. Among the lignin-derived fermentation inhibitors tested, syringaldehyde in low concentrations (1 and 2 mM) in the hydrolysate increased ethanol production, whereas a high concentration (5 mM) inhibited the ethanol production process. A synthetic medium containing syringaldehyde and ferulic acid was prepared to investigate the synergistic effect of inhibitors on ethanol fermentation. Ethanol production decreased in the mixture of 1 mM syringaldehyde and 1 mM ferulic acid, implying that the effect of ferulic acid on ethanol fermentation is comparable to that of syringaldehyde.

• Analytical Science and Technology
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• v.13 no.3
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• pp.323-331
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• 2000

Two chelating resins, XAD-16-TAC and XAD-16-TAO were synthesized by Amberlite XAD-16 macroreticular resin with 2-(2-thiazolylazo)-p-cresol (TAC) and 4-(2-thiazolylazo)-orcinol (TAO) as functional groups. The sorption behaviour of Zr(IV), Th(IV) and U(VI) with two chelating resins were examined with respect to the effect of pH and masking agent by batch methods. It was obtained that the optimum pH was in the range of 5-6, and two chelating resins showed good separation efficiency of Zr(IV) or Th(IV) by using $NH_4F$ as a masking agent. Characteristics of desorption were investigated with 0.1-2 M $HNO_3$ as desorption agent. It was found that 2 M $HNO_3$ showed high desorption efficiency to most of metal ions except Zr(IV). XAD-16-TAC resin is applied to separation and preconcentration of trace Zr(IV) from mixed metal ions. Also, Th(IV) ion can be successfully separated from U(VI) and Zr(IV) ion by using XAD-16- TAO resin.

• Analytical Science and Technology
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• v.8 no.4
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• pp.535-538
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• 1995

This study employs the variety of mixtures of XAD resin and active carbons as concentration base for solid phase extraction (SPE) which has been widely used to preconcentrate and purify phenol and chlorophenols in determination of environmental water samples. In this study, we employed variety of mixtures of copolymer based XAD-4 resin with active carbons. This cartridges shows advantages of both materials, such as better affinity to phenol by active carbon and better mechanical stabilities from XAD resin. The better enrichment factor, pretreatment time, recoveries and limit of detection (LOD) were achieved by the attempts to pack precolumns with both meterials for preconcentration.

• Analytical Science and Technology
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• v.17 no.6
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• pp.454-463
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• 2004

The sorption behavior of some metal ions on XAD-16-CTA chelating resin was investigated by batch method. The sorption of chelating resin was highly selective for Hf(IV), Zr(IV) and Th(IV) at pH 3.0 ~ 6.0 and the maximum sorption capacity of Zr(IV) ion was 0.81 mmol/g. It was successfully applied to the separation of several rare metal ions from mixed metal solutions by using CDTA, EDTA, NTA and $NH_4F$ as masking agent. The elution order of metal ions obtained from breakthrough capacity and the overall capacity at pH 4.0 was Zr(IV)>Th(IV)>Hf(IV)>U(VI)>Cu(II)>In(III)>Pb(II). Desorption characteristics for metal ions was investigated with desorption agents such as HCl, $HNO_3$, $HClO_4$. 2 M HCl showed high desorption efficiency. Th(IV) ion can be successfully separated from mixed metal ions by using XAD-16-CTA cheating resin.