• Korean Chemical Engineering Research
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• 제46권4호
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• pp.783-791
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• 2008

Li-X 제올라이트 흡착탑에서의 $H_2/CO_2$(80:20 vol%), $H_2/CO$(90:10 vol%), $H_2/CH_4$(90:10 vol%)의 이성분계 기체의 흡착 동특성을 연구하였다. 각 계에서 공급유속(6.24~10.24 LPM), 흡착압력(6.1~10.1 bar)에 대한 영향을 살펴보았다. 동특성 실험 결과 파과시간은 공급유속이 적을수록, 흡착압력이 높을수록 증가하였으며 탑 내부 온도의 영향으로 tailing 현상이 발생하였다. Li-X 제올라이트 흡착탑에서 공급 유량과 압력의 확산계수에 의한 LDF식을 사용하여 예측하였다. 본 연구에서는 비등온과 비단열상태, Dual-site langmuir 등온식과 고려하여 해석하였으며 실험 데이터와 비교하였다.

• 한국농림기상학회지
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• 제2권4호
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• pp.190-197
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• 2000

산성비와 같은 요인에 의해 토양으로 유입되는 C $l^{-}$, N $O_3$$^{-}$, S $O_4$$^{2-}$ , P $O_4$$^{3-}$ 그리고 유기산 등의 음이온은 점토광물의 결정구조에 포함되지 않기에 관심 대상이다. 본 논문에서는 포화 또는 불포화 상태의 청원통 Bt 층 토양에 특정 또는 비특정적으로 흡착된 음이온을 혼입치환시킴으로서 토양내 자연 황산이온의 용탈과 파쇄곡선을 조사하였다. 시험결과 파쇄곡선 모양과 형태는 토양입자 표면에서의 치환과 흡착에 따라 영향을 받은 것을 알 수 있었다. 포화와 불포화토양분 조건에서 조사된 옥살릭 이온의 파쇄곡선은 토양 자체의 황산이온을 치환시키는데 작은 공극 수량이 필요하였으며 최대 감지한계에 도달은 불포화보다 포화조건에서 더 빨리 도달하였다. 그리고 오른쪽으로 치우친 파쇄곡선은 비록 토양내 유속변화 순에 따라 영향을 받았지만 주로 각각의 음이온의 서로 다른 흡착 특성에 의해 영향을 받았다고 판단된다. 교호상태의 조건에서 얻어진 파쇄곡선과 용출특성은 C/Co가 0보다는 1에 빨리 도달하였다. 이와 같이 음이온의 비대칭형 형태의 용출 특성은 토양을 통과하는 토양수내의 음이온이 전회를 띠고 있는 토양입자 표면과의 선택적 반응에 기인한다. 그리고 토양을 통과하는 용출수의 pH 변화를 조사한 결과 토양 내의 치환과 흡착반응이 진행되는 6 공극수량 까지는 pH가 7까지 증가되나 이 이후 점진적으로 4까지 감소됨을 알 수 있었다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1998년도 총회 및 춘계 학술발표회 논문집
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• pp.43-49
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• 1998

Retardation effect of heavy metals in soils caused by adsorption onto the surfaces of solids particles is well known phenomena. The adsorption of metal ions has been recognized more strong in clay mineral and organic matter contents rather than sands and gravels. In this study, we investigated the retardation effect in two sandy soils by conducting batch and column tests. The column tests were conducted to obtain the relationship between concentration and time known as breakthrough curve (BTC). We applied pulse type injection of ZnCl$_2$solution on the inlet boundary and monitored the effluent concentration at the exit boundary under steady state condition using EC-meter and ICP-AES. Batch test consisted of an equilibrium procedure for fine fractions collected from two sandy soils for various initial ZnCl$_2$concentrations, and analysis of Zn ions in equilibrated solution using ICP-AES. The results of column test showed that i) the peak concentration of Zn analyzed by ICP was far less than that detected by EC-meter for both soils and ii) travel times for peak concentration were more less identical for two different monitoring techniques. The first result can be explained by ion exchange between Zn and other cations initially present in the soil particles since ICP analysis showed a significant amount of Ca, Mg ions in the effluent. From the second result, we found that retardation effect was not present in these soils due to strong cation exchange capacity of Zn ion over other cations since we did not apply a solution containing more adsorptive cations such as Al. The result of batch test also showed high distribution coefficients (K$_{d}$) for two soils supporting the dominant ion exchange phenomena. Based on the retardation factor obtained from the Kd, we predicted the BTC using CDE model and compared with the BTC of Zn concentration obtained from ICP The predicted BTC, however, disagreed with the monitored in terms of travel time and magnitude of the peak concentrations. The only way to describe the prominent decrease of Zn ion was to introduce decay or sink coefficient in the CDE model to account for irreversible decrease of Zn ions in liquid phase.e.

• 한국토양비료학회지
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• 제32권4호
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• pp.412-420
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• 1999

하수오니 처리 석회질 토양에서의 Cd, Cu 및 Zn의 수송 특성을 조사하기 위하여 하수오니 무처리 토양, 하수오니 50과 100 ton $ha^{-1}$ 처리 토양 및 하수 오니를 대상으로 용출현상 (elution development)과 혼성치환 (miscible displacement) 기술을 이용하여 실험을 수행하였다. 하수오니 50과 100 ton $ha^{-1}$처리 토양의 Cd, Cu 및 Zn 의 용출곡선 (elution curve)과 출현곡선 (breakthrough curve)은 하수오니 무처리 토양의 Cd, Cu 및 Zn의 용출곡선 및 출현곡선과 거의 비슷하였다. Cd, Cu, 및 Zn 10 mg을 처리한 Cd, Cu 및 Zn의 용출곡선은 Cd, Cu 및 Zn을 처리하지 않았을 때의 용출곡선과는 거의 비슷하였으나, Cd, Cu 및 Zn의 50 mg을 처리한 용출곡선과는 크게 달랐다. Cd, Cu 및 Zn 혼합용액 500과 $1000mg\;L^{-1}$을 이용한 Cd, Cu 및 Zn의 출현곡선은 서로 비슷하였으나, Cd, Cu 및 Zn 혼합용액 $100mg\;L^{-1}$을 이용한 출현곡선과는 크게 달랐다. 실험에 사용한 석회질 토양에서 하수오니 50과 100 ton $ha^{-1}$ 처리량은 Cd, Cu 및 Zn의 수송특성에 큰 영향을 주지 못하였으며, Cd와 Zn의 수송특성은 서로 비슷하였으나 Cu의 수송특성은 Cd 과 Zn의 수송 특성과는 크게 달랐다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.337-341
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• 2001

A new method to extract gold from pyrite roster cinder, which combines ultra-fine-grinding with resin-in-pulp, has been studied in this paper. Compared with traditional leaching technology, it can short leaching time, avoid complex filter process, lower sodium cyanide consumption and increase gold recovery by 35%. During leaching, aluminium oxide ball was used as stirred medium, hydrogen peroxide as leaching aid and sodium hexametaphosphate as grinding aid. With the high efficiency and chemistry effect of ultra-fine-grinding, the leaching process was developed and the gold leaching rate may reach 88%. With AM-2 Б resin as abosorber and sulfocarbamide (TU) as eluent, gold was recovered from cyanide pulp by resin-in-pulp. AM-2 Б resin has good adsorbability in cyanide solution(pH=10). It was easy to elude gold from the loaded resin with 0.1㏖/L cholhydric acid and 1㏖/L sulfocabamide. The effect of contact time, temperature and acidity etc. on the gold absorption had been examined with static methods. The results showed that the adsorption and desorption of gold could both reach over 98%. The effects of flow rate of solution on dynamic adsorption and elution of gold had been examined with dynamic methods. Breakthrough curve and elution curve had been drawn in this paper. A mild condition was determined through a number of experiments: leaching time 2 hours, liquid solid ratio 4:1, sodium cyanide 3kg/t, hydrogen peroxide 0.05%, sodium hexametaphosphate 0.05%; adsorption time 30 minutes, temperature 10-3$0^{\circ}C$, resin($m\ell$) solid(g) ratio 1:10, eluent resin ratio 10-20:1, velocity of eluent $1.5m\ell$/min. Under the mild condition, the gold recovery may reach 85%.

• 한국지하수토양환경학회지:지하수토양환경
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• 제26권1호
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• pp.1-7
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• 2021

Air-water interfacial area is of great importance for the analysis of contaminant mass transfer processes occurring in the soil systems. Capillary bundle model has been proposed to estimate the specific air-water interfacial areas in unsaturated soils. In this study, the measured air-water interfacial areas of a soil (loam) using the gaseous interfacial tracer technique were compared to those from capillary bundle model. The measured values converged to the specific solid surface area (7.6×104 ㎠/㎤) of the soil. However, the simulated air-water interfacial areas based on the capillary bundle model deviated significantly from those measured. The simulated values were substantially over-estimated at low end of the water content range, whereas the model under-estimated the air-water interfacial area for the most of the water content range. This under-estimation is considered to be caused by the nature of the capillary bundle model that replaces the soil pores with a bundle of glass capillaries and thus no surface roughness at the inner surface of the capillaries is taken into account for the estimation of the air-water interfacial area with the capillary bundle model. Subsequently, appropriate correction is necessary for the capillary bundle model to estimate the air-water interfacial area in soils. Since the soil-moisture release curve data is the basis of the capillary bundle model, the model can be of use due to its simplicity, while the gaseous tracer technique requires complicated experimental equipment followed by moment analysis of the breakthrough curves. The size distribution profile of the pores filled with gas estimated by the water retention curve was found to be similar to that of particle size at different size range. The shifted distribution of gas-filled pores toward smaller size side compared to the particle size distribution was also found.

• 상하수도학회지
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• 제10권1호
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• pp.121-130
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• 1996

Adsorption isotherms of three trihalomethanes(THMs: $CHCl_3$, $CHBrCl_2$ and $CHBr_2Cl$) and the other organics(p-chlorophenol and sucrose)on activated carbon fibers(ACFs) were measured. Adsorption capacities of the ACFs for these THMs were found to be comparable with or slightly larger than those of granular activated car bons(GACs) which have been widely used for trihalomethanes control in drinking water. Also, the breakthrough curve prediction was successfully carried out using a mathematical model on basis of the assumption that the adsorption equilibrium is instantaneously established when a THM solution contacts the ACF. In practice, THM removal from drinking water was investigated at water works using benchscale ACF adsorptJOn columns. The volume of water treated at a space velocity(SV) of about $100h^{-1}$ was approximately 40 l/g-ACF. The practical adsorption capacities of PCP and sucrose in column adsorption were in good agreement with those of theoretically calculated results using the batch adsorption measurments. And the saturation time model of these substrates in the columns was also agreed succesfully with practical measurments.

• Membrane and Water Treatment
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• 제7권5호
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• pp.403-416
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• 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
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• 제22권2호
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• pp.251-257
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• 2008

Food compost, having a higher organic contents than soil, could be an alternative material to prevent the proliferation of heavy metals contamination in soil. In this study we used a convection-dispersion local equilibrium sorption model(CDE) and a two-site non-equilibrium sorption model to find the effects on the adsorption and transportation of Pb by mixing food compost with soil and we also tried to find the effect of velocity and concentration of the injected solution on the characteristics of Pb. We measured Pb concentrations in injection-liquid and in effluent, and then applied them to CXTFIT program. As a result of column experiments, some parameters(D, R, ${\beta}$, ${\omega}$) used in two-site non-equilibrium adsorption model were obtained. Characteristics of Pb adsorption and transport were analyzed using the parameters(D, R, ${\beta}$, ${\omega}$) obtained from the CXTFIT program, We could know that mixed soil with food compost showed a higher adsorption capacity from the retardation factor(R) calculated from the breakthrough curve(BTCs) of Pb. Rs of soil and mixed soil are 20.45, 37.45 respectively, indicating that the adsorption and the transportation characteristics could be accessed quantitatively by using of two-site non-equilibrium adsorption model.

• Carbon letters
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• 제15권3호
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• pp.203-209
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• 2014

The adsorption of volatile organic compounds (VOCs) was carried out using an activated carbon fiber (ACF) filter in an automobile. The adsorption capacities of formaldehyde, toluene, and benzene on an ACF filter were far better than those of a polypropylene (PP) mat filter and combined (PP+activated carbon) mat filter by batch adsorption in a gas bag. In a continuous flow of air containing toluene vapor through an ACF packed bed, the breakpoint time was very long, the length of the unused bed was short, and sharp "S" -type breakthrough curve was plotted soon after breakpoint, showing a narrow mass transfer zone of toluene on the ACF. The adsorption amount of toluene on the ACF filter was proportional to the specific surface area of the ACF; however, the development of mesopores 2-5 nm in size on the ACF was very effective with regard to the adsorption of toluene. The ACF air clarifier filter is strongly recommended to remove VOCs in newly produced automobiles.