• 공업화학
• /
• 제26권1호
• /
• pp.92-98
• /
• 2015

본 연구에서는 페놀계 활성탄소를 다양한 불소 분압(0.01~0.03 MPa)으로 불소화를 실시하였으며, 불소화된 활성탄소의 6가 크롬 흡착 특성을 조사하였다. BET와 XPS 결과로부터, 불소화 처리된 활성탄소는 비표면적 및 총 기공부피가 각각 24.7, 58.8% 증가되었으며, 활성탄소 표면에 불소 관능기가 도입됨을 알 수 있었다. 불소 분압이 0.02 MPa일 때, 크롬이온 흡착에 최적화된 표면처리 조건임을 확인하였다. 또한, 초기농도 300 mg/L에서 98%의 제거효율을 나타내었으며, 이러한 결과는 미처리 활성탄소와 비교하여 약 3배 증가됨을 알 수 있었다. 한편, 불소화된 활성탄소의 크롬이온 흡착은 미처리 활성탄소와 대조적으로 30 min 이내에 완료되었으며, 이러한 현상은 페놀계 활성탄소의 표면에서 크롬 이온과의 친화성 증가에 의한 것으로 판단되었다.

• 자원리싸이클링
• /
• 제17권2호
• /
• pp.63-69
• /
• 2008

폐알칼리망간전지 분말에 대한 $Ni^{2+}$의 흡착 거동을 살펴보기 위하여 흡착제의 양, 홉착질의 초기농도 및 반응온도를 변화시켜 가며 그 특성을 조사하였다. $Ni^{2+}$의 흡착반응은 유사이차반응속도를 잘 따르는 것을 알 수 있었으며 $Ni^{2+}$의 초기농도가 증가함에 따라 유사이차반응속도상수($k_2$)는 감소하는 것으로 나타났다. 흡착평형을 표현하는데 널리 이용되는 Langmuir와 Freundlich 흡착 모델에 평형흡착 결과를 적용하였으며 Freundlich isotherm모델에 적합한 것으로 나타났다. 반응온도가 증가함에 따라 평형흡착량이 증가하여 흡착반응은 흡열반응의 양상을 보였으며 온도의 변화에 대한 실험결과로부터 ${\Delta}H^{\circ},\;{\Delta}G^{\circ}$ 그리고 ${\Delta}S^{\circ}$ 열역학적 변수를 도출하였다.

• Nuclear Engineering and Technology
• /
• 제46권6호
• /
• pp.847-856
• /
• 2014

Spent resin waste containing a high concentration of $^{14}C$ radionuclide cannot be disposed of directly. A fundamental study on selective $^{14}C$ stripping, especially from the IRN-150 mixed bed resin, was carried out. In single ion-exchange equilibrium isotherm experiments, the ion adsorption capacity of the fresh resin for non-radioactive $HCO_3{^-}$ ion, as the chemical form of $^{14}C$, was evaluated as 11mg-C/g-resin. Adsorption affinity of anions to the resin was derived in order of $NO_3{^-}$ > $HCO_3{^-}{\geq}H_2PO_4{^-}$. Thus the competitive adsorption affinity of $NO_3{^-}$ ion in binary systems appeared far higher than that of $HCO_3{^-}$ or $H_2PO_4{^-}$, and the selective desorption of $HCO_3{^-}$ from the resin was very effective. On one hand, the affinity of $Co^{2+}$ and $Cs^+$ for the resin remained relatively higher than that of other cations in the same stripping solution. Desorption of $Cs^+$ was minimized when the summation of the metal ions in the spent resin and the other cations in solution was near saturation and the pH value was maintained above 4.5. Among the various solutions tested, from the view-point of the simple second waste process, $NH_4H_2PO_4$ solution was preferable for the stripping of $^{14}C$ from the spent resin.

• 분석과학
• /
• 제21권2호
• /
• pp.109-116
• /
• 2008

1%, 2%, 6% 및 12%의 가교도를 가진 스틸렌(제4류 위험물) 디비닐벤젠 공중합체에 1-aza-18-crown-6 거대고리 리간드를 치환반응으로 결합시켜 수지들을 합성하였다. 이들 수지의 합성은 염소 함량, 원소 분석, 열중량 분석, 전자 현미경, 그리고 IR-스펙트럼으로 확인하였다. 수지 흡착제에 의한 우라늄 이온의 흡착에 미치는 pH, 시간, 수지의 가교도 그리고 용매의 유전상수에 따른 영향들을 조사하였다. 우라늄 이온은 pH 3 이상에서 큰 흡착율을 보였으며, 금속 이온들의 흡착 평형은 2 시간 정도였다. 한편, 에탄올 용매에서 수지에 대한 흡착 선택성은 $UO{_2}^{2+}$ > $Zn^{2+}$ > $Lu^{3+}$ 이온이었고, 우라늄 이온의 흡착력은 1%, 2%, 6% 및 12%의 가교도 순 이었으며, 용매의 유전상수 크기에 반비례하였다.

• 공업화학
• /
• 제5권6호
• /
• pp.1024-1029
• /
• 1994

경북 감포지역에서 산출되는 천연 제올라이트를 각기 다른 농도의 HCl과 NaOH로 화학처리한 시료와 금속양이온 교환한 시료를 제조 하였다. 이들 시료에 대한 질소의 흡착특성을 $25^{\circ}C$, 100~760 torr의 범위에서 조사하였다. 산처리한 시료의 질소 흡착량은 처리하기 전보다 감소하였으며, 알칼리 처리한 시료는 많이 증가하였다. 0.5N-HCl 처리 후 0.5N-NaOH로 연속처리한 경우 약 200% 정도 흡착량이 개선되었으나, 알칼리 처리 후 산으로 연속처리한 경우에는 오히려 감소하였다. $Na^+$, $K^+$, $Cs^+$를 이온교환한 경우 이온의 크기가 증가할수록 흡착량은 감소했으며, $Mg^{2+}$, $Ca^{2+}$, $Ba^{2+}$를 이온교환한 경우는 이온의 크기가 증가할수록 흡착량이 증가하였다.

• 폴리머
• /
• 제25권1호
• /
• pp.49-55
• /
• 2001

비닐계 단량체인 아크릴로니트릴과 스티렌을 E-beam 전조사법에 의해 폴리프로필렌 섬유에 그라프트 반응시켜 PP-g-(AN/St) 공중합체를 제조한 후 아미드옥심기와 슬폰기를 도입하여 이관능성 이온교환섬유를 제조하였다. 그라프트율은 단량체 내에 아크릴로니트릴의 조성이 감소할수록 증가하였으며 최대 101.1%이었고 최대 아미드옥심화율은 7.2 mmol/g이었다. 또한 섬유상 이온교환체의 초기 열분해 온도는 120 ${\circ}C$ 이었고 함수율은 공중합체 내에 아미드옥심화율이 증가할수록 감소하였고 슬폰화율이 증가할수록 증가하는 경향을 나타냈다. APP-g-AN, SPP-g-St, ASPP-g-(AN/St) 이온교환체의 우라늄 흡착량은 각각 12.4, 34, 38mg/g이었으며 최적 흡착시간은 약 50시간이었다. 우라늄 흡착 실험결과, 본 실험에서 합성한 이온교환체 ASPP-g-(AN/St)는 $UO_2^{2+}$에 대하여 우수한 성능을 보였다.

• Food Science and Biotechnology
• /
• 제17권2호
• /
• pp.330-335
• /
• 2008

Water vapor adsorption kinetics of 3 different types of chitosan-based films, i.e., control chitosan, chitosan/montmorillionite (Na-MMT), and chitosan/silver-zeolite (Ag-Ion) nanocomposite films, were investigated at temperature range of $10-40^{\circ}C$. In all the films, water vapor is initially adsorbed rapidly and then it comes slowly to reach equilibrium condition. Reasonably good straight lines were obtained with plotting of 1/($m-m_0$) vs. l/t. It was found that water vapor adsorption kinetics of chitosan-based films was accurately described by a simple empirical model and the rate constant of the model followed temperature dependence according to Arrhenius equation. Arrhenius kinetic parameters ($E_a$ and $k_o$) for water vapor adsorption by chitosan-based films showed a kinetic compensation effect between the parameters with the isokinetic temperature of 315.52 K.

• 한국재료학회지
• /
• 제14권3호
• /
• pp.229-234
• /
• 2004

All the applications of natural zeolites make use of one or more of their physical and chemical properties: adsorption, ion-exchange and related molecular sieve properties, dehydration and rehydration, and siliceous composition. Accordingly, the applications of zeolite have been carried out in the various aspects because of its large cation exchange capacity and adsorption properties. In this paper, the adsorption effect of heavy metal ions in wastewater on zeolite mineral by batch adsorption process is studied. The amounts of adsorbed ions were variable by original pH and ionic concentration, especially original pH of solution had an important effect on the adsorption. In case of low pH solution, e.g. below 3.0, clinoptilolite adsorbed $Pb^{2+}$ ,$ Cd ^{2+ }$ , $Cu^{2+}$ and $Zn^{ 2+}$ , but mordenite almost did not adsorb except $Pb^{2+}$ . Under the same conditions, these ions were more adsorbed on clinoptilolite than on mordenite mineral. The velocity of adsorption was relatively fast and it was confirmed by shaking test that the equilibrium of adsorption could be attained in about one hour. The species of exchangeable cation of zeolite had an effect on its removing ability and zeolite of the sodium-exchanged type was the best.

• Membrane and Water Treatment
• /
• 제7권5호
• /
• pp.403-416
• /
• 2016

The possibility of using carica papaya leaf powder for removal of copper from wastewater as a low cost adsorbent was explored. Different parameters that affect the adsorption process like initial concentration of metal ion, time of contact, adsorbent quantity and pH were evaluated and the outcome of the study was tested using adsorption isotherm models. A maximum of 90%-94.1% copper removal was possible from wastewater having low concentration of the metal using papaya leaf powder under optimum conditions by conducting experimental studies. The biosorption of copper ion was influenced by pH and outcome of experimental results indicate the optimum pH as 7.0 for maximum copper removal. Copper distribution between the solid and liquid phases in batch studies was described by isotherms like Langmuir adsorption and Freundlich models. The adsorption process was better represented by the Freundlich isotherm model. The maximum adsorption capacity of copper was measured to be 24.51 mg/g through the Langmuir model. Pseudo-second order rate equation was better suited for the adsorption process. A dynamic mode study was also conducted to analyse the ability of papaya leaf powder to remove copper (II) ions from aqueous solution and the breakthrough curve was described by an S profile. Present study revealed that papaya leaf powder can be used for the removal of copper from the wastewater and low cost water treatment techniques can be developed using this adsorbent.

• 상하수도학회지
• /
• 제25권3호
• /
• pp.359-366
• /
• 2011

The feasibility of using volcanic ash for lead ion removal from wastewater was evaluated. The adsorption experiments were carried out in batch tests using volcanic ash that was treated with either NaOH or HCl prior to the use. Volcanic ash dose, temperature and initial Pb(II) concentration were chosen as 3 operational variables for a $2^3$ factorial design. Ash dose and concentration were found to be significant factors affecting Pb(II) adsorption. The removal of Pb(II) was enhanced with increasing volcanic ash dose and with decreasing the initial Pb(II) concentration. Pb(II) adsorption on the volcanic ash surface was spontaneous reaction and favored at high temperatures. Calculation of Gibb's free energy indicated that the adsorption was endothermic reaction. The equilibrium parameters were determined by fitting the Langmuir and Freundlich isotherms, and Langmuir model better fitted to the data than Freundlich model. BTV(base-treated volcanic ash) showed the maximum adsorption capacity($Q_{max}$) of 47.39mg/g. A pseudo second-order kinetic model was fitted to the data and the calculated $q_e$ values from the kinetic model were found close to the values obtained from the equilibrium experiments. The results of this study provided useful information about the adsorption characteristics of volcanic ash for Pb(II) removal from aqueous solution.