• Analytical Science and Technology
• /
• v.26 no.1
• /
• pp.11-18
• /
• 2013

Perchlorate ($ClO{_4}^-$) is the material that is used as propellants of rockets and material of explosive as a form of ammonium perchlorate salts. Ammonium perchlorate solution of high concentration is recovered from expired rocket through demilitarization process by the water-jet method. If people take perchlorate in food and water, it interferes with adsorption of iodide which is the substance needed to synthesize thyroid hormone in the thyroid gland. It has an bad influence upon disturbing pregnancy and synthesis of growth hormone. So the effective method is necessary to remove perchlorate anion in water. By considering economic aspect, we studied effective desorption (regeneration) of perchlorate anion from adsorbent with studies on removal and adsorption of perchlorate anion. Desorption experiment was conducted as batch type. Depending on various conditions (concentration, pH, cation anion form) elution, we evaluated amount, efficiency of desorption(amount of adsorption/desorption ${\times}$ 100). Also, research confirmed the efficiency of mixed resins between anion exchange resin and activated carbon and expected synergic effect from advantages of both adsorbents.

• Resources Recycling
• /
• v.30 no.4
• /
• pp.54-63
• /
• 2021

Vanadium and tungsten can be obtained by separating/recovering the leaching solution from a spent SCR DeNO_X catalyst using the soda roasting-water leaching process. Therefore, in this study, the adsorption/desorption mechanism of vanadium and tungsten in an ion-exchange column was investigated using Lewatit MonoPlus MP 600, a strong basic anion exchange resin. The operating conditions for the separation of vanadium and tungsten in the ion-exchange column was intended to present. By conducting a continuous adsorption experiment in a pH 8.5 solution, the adsorption capacity of vanadium and tungsten was found to be 44.75 and 64.92 mg/(g of resin), respectively, which showed that the adsorption capacity of tungsten was larger than that of vanadium because of the difference in ion charge. Vanadium has a higher affinity for MP 600 than tungsten. Consequently, as the vanadium-containing solution is eluted through the ion exchange resin onto which tungsten is adsorbed, the adsorbed tungsten is exchanged with vanadium and desorbed. A continuous experiment was performed with a solution of vanadium and tungsten prepared at the same concentration as the spent SCR DeNO_X catalyst leachate. The adsorption capacity of vanadium was found to be 48.72 mg/(g of resin) and 80% of the supplied vanadium was adsorbed; in contrast, almost no tungsten was adsorbed. Therefore, vanadium and tungsten were separated effectively. The ion exchange resin was treated with 2 M HCl at 15 mL/h, and 97.7% of the vanadium(99% purity) could be desorbed. After desorption, NH₄Cl was added to precipitate ammonium polyvanadate at 90℃ and recover 93% of the vanadium.

• Journal of the Korea Institute of Building Construction
• /
• v.20 no.1
• /
• pp.1-9
• /
• 2020

Chloride ion, which penetrates into the cement composites from the outside, generally diffuses by the concentration gradient. Chloride ions are adsorbed by the chemical reaction with cement hydrates. Recent studies have shown that anion exchange resin (AER) powder can effectively adsorb the chloride ion in the cement composites, and thus, the cement composites containing AER have a high chloride adsorption capacity and a good resistance for chloride penetration. In this study, the chloride adsorption ability of the AER powder was investigated under the conditions of distilled water and calcium hydroxide saturated solution to determine if the AER powder is less effective to increase the chloride adsorption ability after grinding process. The chloride adsorption ability of AER powder was compared with the previous research about the chloride adsorption of AER bead. In addition, the compressive strength, chloride diffusion coefficient (using NT Build 492 method), and the chloride profile of cement mortar substituted with AER powder were investigated. There was no decrease in the chloride adsorption capacity of AER powder but increase in the kinetic property for chloride adsorption after the grinding process. The AER powder could absorb the chloride ion in the mortar quickly, and showed better chloride ion adsorption ability than the cement hydrates.

• Resources Recycling
• /
• v.29 no.5
• /
• pp.38-47
• /
• 2020

In this study, factors affecting the adsorption reaction for the separation/recovery of V and W using Lewatit monoplus MP 600, a strong basic anion exchange resin, from the leachate obtained through the soda roasting-water leaching process from the spent SCR DeNO_X catalyst investigated and the adsorption mechanism was discussed based on the results. In the case of the mixed solution of V and W, both ions showed a high adsorption ratio at pH 2-6, but the adsorption of W was greatly reduced at pH 8. In the adsorption isothermal experiment, both V and W were fitted well at the Langmuir adsorption isotherm, and the reaction kinetics were fitted well at pseudo-second-order. As a result of conducting an adsorption experiment by adjusting the pH with H₂SO₄ to remove Si, which inhibits the adsorption of V and W from the leachate, the lowest W adsorption ratio was shown at pH 8.5. Desorption of W was hardly achieved in strongly acidic solutions, and desorption of V was well performed in both strongly acidic and strongly basic solutions.

• Journal of the Korean Chemical Society
• /
• v.42 no.2
• /
• pp.172-176
• /
• 1998

An anion exchange resin which has Alizarin Red S (ARS) as functional group was prepared by batch method. The resin is stable in acidic solutions below 0.5 M hydrochloric acid, nitric acid and sulfuric acid and adsorption capacity of Fe(Ⅱ) ion on the resin was larger than other metal ions. The preconcentration and the separation of Fe(Ⅱ) ion from the mixture solution were carried out with the pH 4.5 buffer solution and 0.1 M $HNO_{3}$ as eluents.

• Clean Technology
• /
• v.12 no.1
• /
• pp.37-44
• /
• 2006

The effectiveness of inorganic oxides (DT-30), anionic exchange resin (DT-60) and carbon absorbent (DT-80, DT-90) on the equilibrium and continuous separation characteristics and removal of cobalt, cesium and iodide ion in the waste water was investigated. As a result, DT-30, DT-80 or DT-90, and DT-60 showed excellent separation properties on the cesium, cobalt and iodide respectively. In the equilibrium experiment, the adsorption amount of cesium for DT-30 increased with temperature, but increasd largely with pH. In case of DT-80, adsorption of cobalt was depended on pH but was not influenced by temperature. In the continuous system by passing a heavy metal ion solution through the ion exchange tower, DT-30, DT-90 and DT-60 showed good separation characteristic for cesium, cobalt and iodide respectively. In this case, separation characterization of DT-30 on the cesium and of DT-60 on the iodide were better than that of DT-90 on the cobalt. From the experiment on the effect of impurities on the ion exchange characteristics, impurities such as surfactant and oil did not influence the efficiency of DT-90. In the mean while, ion separation capacity of DT-30 were decreased largely by impurities such as surfactant and oil. Also, surfactant had a strong influence on the effectiveness of DT-60. Accordingly, it turned out to be very important thing that impurities should be removed in the preprocessing stage.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.5 no.3
• /
• pp.221-227
• /
• 2007

Fenton's reagent is applied to directly decompose the ion-exchange resins, IRN-78 and the mixed resin with IRN-77. The newly applied procedures is to dry the resin first and the catalyst solution is completely absorbed into the resin, then a limited dose of $H_2O_2$ is introduced for an effective reaction between the reagents within the resin. As a characteristic on the decomposition of IRN-78, the resin mixture should be heated to $40^{\circ}C$ to induce the initial reaction and lag time is also needed for about 20 minutes until the main reaction occurs. The effectiveness of the decomposition is investigated using $CuSO_4,\;Cu(NO_3)_2\;and\;FeSO_4$ as a catalyst and the decomposition rate is compared depending on the concentration of each catalyst and the amount of $H_2O_2$. The most effective catalyst was found to be $FeSO_4$ for IRN-78 alone and the mixed resin with IRN-77, and $FeSO_4$ showed a special effect that the reaction was initiated without heating and a lag time. Furthermore, the optimum concentration of the catalyst for each resin and the mixed one is suggested in the view point of the amount of $H_2O_2$ needed and the stability of the decomposition reaction.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2008.11a
• /
• pp.423-427
• /
• 2008

지하수 중에 함유된 불소이온을 제거하기 위한 흡착제로 상용의 음이온교환수지(PA), 란탄산화물(La) 및 수산화아파타이트(HAp)를 선정하고 각각의 흡착특성을 회분식 실험을 통해 검토하였다. 그 결과를 요약하면 다음과 같다. 1) PA, La 및 HAp의 불소흡착은 Fruendlich isodtherm model 및 Pseudo-second-order kinetics model과 일치하는 거동을 보였다. 2) D-R model로부터 구한 흡착에너지는 9.66$\sim$12.90 kJ/mol로 이온교환메커니즘을 나타내는 흡착에너지 6$\sim$16 kJ/mol의 범위에 속하였다. 3) Van't Hoff 식에 이용하여 구한 ${\Delta}H^{\circ}$ 및 ${\Delta}G^{\circ}$값은 각각 3.40$\sim$89.28 kJ/mol과 -12.26$\sim$-13.76 kJ/mol의 범위를 보여 모두 흡착과정이 발열반응이며 자발적으로 일어나는 조건임을 알 수 있었다. 4) PA는 pH 6$\sim$8인 중성영역에서 가장 높은 불소 제거율을 보였으며, La과 HAp는 산성영역으로 갈수록 불소 제거율이 증가하는 특성을 나타내었다. 5) 불소에 대한 흡착선택성은 La$\geq$HAp>PA 순으로 높았으며, La의 경우 불소를 제외한 모든 음이온에 대한 흡착능이 없을 정도로 불소에 대한 흡착 특이성을 보였다.

• Proceedings of the Membrane Society of Korea Conference
• /
• 1996.10a
• /
• pp.80-81
• /
• 1996

일반적으로 고분자전해질은 고유의 독특한 특성으로 고분자 분리막, 이온교환수지, 의료용고분자등에 널리 응용이 되고 있다. 이러한 고분자전해질은 음이온성과 양이온성이 있으며, 그 이온적성질으로 인하여 반대의 전하를 띄는 고분자전해질들끼리 결합하는 성질을 가지고 있다. 이러한 고분자전해질 착체는 고분자전해질과는 또 다른 고유한 특성을 나타내고 있으며, 특히 고분자분리막과 의료용재료 분야에 응용가능성이 큰 물질이다. 특히 양이온성과 음이온성을 동시에 보유하고 있는 구조적 특성에 의하여 산성과 염기성 모두에서 감응성을 나타낼 수 있다. 일반적으로 고분자 겔의 경우 산성 또는 염기성 영역에서 해리되는 특성에 의하여 pH 감응성을 나타내지만 한쪽 영역에서만 특성을 나타내고 있다. 본 실험에서는 키토산과 폴리아크릴산으로 제조된 고분자전해질착체를 이용하여 pH변화에 따른 함수거동을 관찰함으로써 양쪽의 pH 감응성을 고찰해보고자 하였다.

• Journal of Conservation Science
• /
• v.22
• /
• pp.99-108
• /
• 2008

This research aimed to provide a scientific methodology for removing white and black/brown coloured stains on the wall paintings of tombs of Jinpari No 1 and No 4. in the Democratic People's Republic of Korea. For the analysis of chemical composition of stains of the samples from the wall paintings, a microscope and SEM/EDX were used. The analysis confirmed that the fomula of white coloured stains should be $CaSO_4$ or $CaCO_3$ and the black/brown coloured stains should be $CaSO_4$ or $CaCO_3$ with soil deposition. Because of the difficulties of testing several cleaning solutions on sample patches of large area of the painting, the author considered a risk-free cleaning solution as being the most appropriate one, with Ammonium bicarbonate and Anion exchange resin showing satisfactory cleaning effect without visible side effects. For the removal of dense layer of stains, the research suggested that physical cleaning should be followed by applying a cleaning solution.