• 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.

• 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.

• Membrane and Water Treatment
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• v.6 no.6
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• pp.439-449
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• 2015

Carbolic Acid which is called phenol is one of the important starting and/or intermediate materials in various industrial processes. However, its excessive release into environment poses a threat to living organisms, as it is a highly carcinogens and hazardous pollutant even at the very low concentration. Thus removal of phenol from polluted environments is very crucial for sustainable remediation process. We developed a low cost adsorption method for separating phenol from a model aqueous solution. The phenol adsorption was studied using two adsorbents i.e., Amber lite XAD-16 and Amber lite XAD-7 HP with a constant amount of resin 0.1 g at varying aqueous phenol concentrations ($50-200mgL^{-1}$) at room temperature. We compared the efficacy of two phenol adsorbents for removing higher phenol concentrations from the media. We investigated equilibrium and kinetics studies of phenol adsorption employing Freundlich, Temkin and Langmuir isotherms. Amberlite XAD-16 performed better than Amberlite XAD-7 HP in terms of phenol removal efficiency that amounted to 95.52%. Pseudo second order model was highly fitted for both of the adsorption systems. The coefficient of determination ($R^2$) with Langmuir isotherm was found to be 0.98 for Amberlite XAD-7 HP. However, Freundlich isotherm showed $R^2$ value of 0.95 for Amberlite XAD-16, indicating that both isotherms could be described for the isotherms on XAD-7 HP and Amberlite XAD-16, respectively.

• 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 the Korean Chemical Society
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• v.34 no.3
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• pp.267-279
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• 1990

The adsorption mechanisms of phenols on XAD-2 and XAD-7 resins were studied by using the distribution coefficient(log Kd) measured in the optimum adsorption conditions. It was observed that the Langmuir adsorption isotherm, indicating a molecular size-dependent adsorption, was appropriate for characterizing the adsorption behaviors of phenols on XAD-2 and XAD-7 resins. The adsorption energies of phenols on XAD resins were calculated by Lennard-Jones potential equation. In the calculation of the adsorption energy, the molecular radii and dipole moments of the resins and phenols were calculated by their van der Waals volumes and Debye equation, respectively. The stacking factor (F) were determined from the radio of the equilibrium distance to the stacking distance of molecules. In order to explain the adsorption energy calculated from the stacking factor it was compared with the adsorption enthalpy for each of phenols which was experimentally determined by batch adsorption shake method. It was observed that the adsorption enthalpy of phenolate ions on the XAD resins was likely to be more seriously affected by dispersion interaction than by a dipole or a charge interaction.

• 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.

• Bulletin of the Korean Chemical Society
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• v.27 no.1
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• pp.77-81
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• 2006

The commercially available Amberlite XAD-2 and XAD-4 resins were modified with macrocyclic protoporphyrin IX (PPIX) or tetrakis(p-carboxyphenyl) porphyrin (TCPP) to enhance the adsorption capacity for phenol and chlorophenols. The chemically modified polymeric adsorbents (XAD-2+PPIX, XAD-2+TCPP, XAD-4+PPIX, and XAD-4+TCPP) were applied to the solid phase extraction as an adsorbent material for the preconcentration of phenol and chlorophenols in environmental waters. Generally, the synthesized adsorbents showed higher recoveries than underivatized adsorbents, XAD-2 and XAD-4, without matrix interferences. Especially, XAD-4+PPIX showed more than 90% recoveries for all compounds used in this study including hydrophilic phenol. The major factor for the increase of the adsorption capacity was the increase of $\pi$-$\pi$ interaction between adsorbents and samples due to the introduction of the porphyrin molecule. However, the breakthrough volumes and recovery values of the XADs+TCPP columns were slightly decreased for the bulky chlorophenols such as TCP and PCP. Using molecular mechanics methods, the structures of TCPP and PPIX were compared with that of porphine, the parent molecule of porphyrin. Four bulky p-carboxyphenyl groups of TCPP were torsional each other, thus the molecular plane of TCPP were not on the same level. In conclusion, the decrease of breakthrough volumes and recovery values of XADs+TCPP columns for bulky phenols can be explained by the steric hindrance of the $\pi$-$\pi$ interaction between porphyrin plane and the phenols.

• Analytical Science and Technology
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• v.9 no.3
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• pp.279-291
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• 1996

The new chelating resins, XAD-2, 4, 16-TAC and XAD-2, 4, 16-TAO were synthesized by Amberlite XAD-2, XAD-4, and XAD-16 macroreticular resins with 2-(2-thiazolylazo)-p-cresol(TAC) and 4-(2-thiazolylazo)orcinol(TAO) as functional groups and were characterized by elemental analysis and FT-IR spectrometry. It was found that the content of functional group in chelating resin was 0.60mmol/g in XAD-16-TAC and 0.68mmol/g in XAD-16-TAO respectively. The chelating resins were stable in acidic and alkaline solution and can be reused over 10 times. The sorption behavior of some metalions to two chelating resins was investigated by batch method, which included batch equilibrium, effect of pH, coexisting ions and masking agent. For the optimum condition of sorption, the time required for equilibrium was about 1 hour and optimum pH was 5. In the presence of anions such as ${SO_4}^{2-}$ and $CH_3COO^-$, the sorption of U(VI) ion was slightly reduced but other anions such as $Cl^-$ and $NO{_3}^-$ revealed no interference effect. Also, sorption capacity of U(VI) ion was decreased by addition of $CO{_3}^{2-}$ ion because of complex formation of $[UO_2(CO_3)_3]^{4-}$, but alkali metals and alkali earth metals including Na(I), K(I), Mg(II), and Ca(II) were not affected for the sorption extent. Masking agent, NTA showed better separation efficiency of U(VI) ion from coexisting metal ions such as Th(IV), Zr(IV), Hf(IV), Cu(II), Cd(II), Pb(II), Ni(II), Zn(II) and Mn(II) than EDTA, CDTA.

• 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.