• Carbon letters
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• 제12권2호
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• pp.112-115
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• 2011

The scope of this work investigates the relationship between the amount of oxygen-functional groups and hydrogen adsorption capacity with different concentrations of phosphoric acid. The amount of oxygen-functional groups of activated carbons (ACs) is characterized by X-ray photoelectron spectroscopy. The effects of chemical treatments on the pore structures of ACs are investigated by $N_2$/77 K adsorption isotherms. The hydrogen adsorption capacity is measured by $H_2$ isothermal adsorption at 298 K and 100 bar. In the results, the specific surface area and pore volume slightly decreased with the chemical treatments due to the pore collapsing behaviors, but the hydrogen storage capacity was increased by the oxygen-functional group characteristics of AC surfaces, resulting from enhanced electron acceptor-donor interaction at interfaces.

• 한국물환경학회지
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• 제23권2호
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• pp.216-221
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• 2007

The adsorption characteristics of malachite green on waste garnet have been investigated for its treatment from aqueous solution by employing waste garnet which is generated from the abrasive production process as an adsorbent. The influential factors examined were the initial concentration of malachite green in solution, reaction temperature, and the amount of adsorbent. Also, the effect of the modification of the surface of adsorbent on adsorption was examined. As the initial malachite green was increased with reaction temperature and the color removal of malachite green-containing solution was promoted with the amount of adsorbent. Finaly, increased adsorption of malachite green could be attained when the surface of glass was modified by hexamethyldisilazane.

• Korean Chemical Engineering Research
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• 제56권1호
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• pp.14-23
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• 2018

The effect of dodecylbenzene sulfonic acid (DBSA) with different addition amount of DBSA ($M_{DBSA}$), temperatures and solvent-to-oil ratio (SOR, v/v) on asphaltene aggregation in a solvent deasphalting system was investigated. Increasing the $M_{DBSA}$ at SOR 10 and $55^{\circ}C$ caused the asphaltene removal ratio (ARR) to increase first, then maximize at 1 wt% of $M_{DBSA}$ and then decrease continuously. Based on the SARA (saturate, aromatic, resin, asphaltene) composition, the adsorption amount of DBSA on the asphaltene surface and the self-aggregation of the DBSA, the reason for the change in ARR with $M_{DBSA}$ was found due to the adsorption mechanism. In addition, the asphaltene-resin-DBSA colloidal size confirmed the change of adsorption behavior between the asphaltene and DBSA. Based on the results of this study, a hypothetical adsorption mechanism of DBSA on asphaltene aggregation in the solvent deasphalting system was conceived of and proposed.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.148.2-148.2
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• 2013

We prepared hydrophobic PDMS-coated porous silica as pre-concentration adsorbent for chemical warfare agents (CWAs). Since CWAs can be harmful to human even with a small amount, detecting low-concentration CWAs has been attracting attention in defense development. Porous silica is one of the promising candidates for CWAs pre-concentration adsorbent since it is thermally stable and its surface area is sufficiently high. A drawback of silica is that adsorption of CWAs can be significantly reduced due to competitive adsorption with water molecule in air since silica is quite hydrophilic. In order to solve this problem, hydrophobic polydimethylsiloxane (PDMS) thin film was deposited on silica. Adsorption and desorption of chemical warfare agent (CWA) simulants (Dimethylmethylphosphonate, DMMP and Dipropylene Glycol Methyl Ether, DPGEM) on bare and PDMS-coated silica were studied using temperature programed desorption (TPD) with and without co-exposing of water vapor. Without exposure of water vapor, desorbed amount of DMMP from PDMS-coated silica was twice larger than that from bare silica. When the samples were exposed to DMMP and water vapor at the same time, no DMMP was desorbed from bare silica due to competitive adsorption with water. On the other hand, desorbed DMMP was detected from PDMS-coated silica with reduced amount compared to that from the sample without water vapor exposure. Adsorption and desorption of DPGME with and without water vapor exposing was also investigated. In case of bare silica, all the adsorbed DPGME was decomposed during the heating process whereas molecular DPGME was observed on PDMS-coated silica. In summary, we showed that hydrophobic PDMS-coating can enhance the adsorption selectivity toward DMMP under humid condition and PDMS-coating also can have positive effect on molecular desorption of DPGME. Therefore we propose PDMS-coated silica could be an adequate adsorbent for CWAs pre-concentration under practical condition.

• 한국물환경학회지
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• 제38권2호
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• pp.82-94
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• 2022

In this study, chemically modified biochar (NSBP500, KSBP500, OSBP500) derived from starfish was utilized to improve the adsorption ability of the SBP500 (Starfish Biochar Pyrolyzed at 500℃) in a solution contaminated with heavy metals. According to the biochar modification performance evaluation batch tests, the removal rate and adsorption amount of NSBP500 increased 1.4 times for Cu, 1.5 times for Cd, and 1.2 times for Zn as compared to the control sample SBP500. In addition, the removal rate and adsorption amount of KSBP500 increased 2 times for Cu, 1.8 times for Cd, and 1.2 times for Zn. The removal rate and adsorption amount of OSBP500 increased 5.8 times for Cu. The FT-IR analysis confirmed the changes in the generation and movement of new functional groups after adsorption. SEM analysis confirmed Cu in KSBP500 was in the form of Cu(OH)₂ and resembled the structure of nanowires. The Cd in KSBP500 was densely covered in cubic form of Cd(OH)₂. Lead(Pb) was in the form of Pb₃(OH)₂(CO₃)₂ in a hexagonal atomic layer structure in NSBP500. In addition, it was observed that Zn was randomly covered with Zn₅(CO₃)₂(OH)₆ pieces which resembled plates in KSBP500. Therefore, this study confirmed that biochar removal efficiency was improved through a chemical modification treatment. Accordingly, adsorption and precipitation were found to be the complex mechanisms behind the improved removal efficiency in the biochar. This was accomplished by electrostatic interactions between the biochar and heavy metals and ion exchange with Ca²⁺.

• 농약과학회지
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• 제2권1호
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• pp.70-78
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• 1998

토양에 살포된 양이온성 농약인 paraquat가 점토광물, 유기물 및 토양 시료에서의 흡착량, 흡착 특성, 흡착 형태 및 탈착간의 상호관계에 관하여 조사하였다. 점토광물에 의한 paraquat의 흡착 시간은 유기물 및 토양 시료에 비하여 빠르게 나타났다. 팽창형 점토광물인 montmorillonite에 의한 흡착은 총흡착량 뿐만 아니라 CEC에 대한 흡착 비율에서도 다른 흡착제에 비하여 높게 나타났다. Humic acid와 fulvic acid는 점토광물인 kaolinite와 토양 시료보다도 많은 양의 paraquat을 흡착하였다. 토양 시료에 의한 흡착은 CEC의 약 21% 정도로 점토광물에 비하여 25-50% 수준인 것으로 나타났다. Paraquat의 흡착 형태별 분포 시험에서 점토광물 및 토양 시료에서는 tightly bound type의 비율이 가장 높았으나, humic acid및 fulvic acid에서는 loosely bound type의 비율이 높게 나타났다. 유기물을 제거한 토양 시료의 paraquat 흡착량은 유기물을 제거하지 않은 토양의 85.1-95.5% 정도이며, unbound 및 loosely bound type의 비율이 감소한 반면 tightly bound type의 비율이 증가하였다. 용액중에 경쟁 양이온이 공존하는 경우, paraquat의 흡착은 유기물에서 약 35%정도 감소하였으나 montmorillonite에서는 감소 효과가 나타나지 않았으며, 경쟁 양이온의 종류에 따른 차이는 나타나지 않았다. 흡착제가 양이온으로 포화되어 있는 경우 paraquat의 흡착은 유기물에서 75% 정도, 토양 시료에서 65% 정도 감소하였으나 montmorillonite에서는 약 30% 정도만이 감소하였다. 흡착 형태에 따른 paraquat의 탈착 시험에서 tightly bound type은 흡착제의 종류에 관계없이 pH 조절, 초음파처리, 양이온의 첨가에 의하여서는 탈착되지 않았다. Loosely bound type의 paraquat는 흡착제의 종류 및 탈착방법에 따라 탈착율이 다르게 나타났으나, 양이온 첨가나 pH조절과 같은 화학적 변화 또는 초음파처리와 같은 물리적 충격에 의하여 탈착될 수 있는 것으로 나타났다.

• 상하수도학회지
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• 제26권3호
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• pp.431-442
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• 2012

The purpose of this study, is to separate magnetic separation devices using permanent magnets by using magnetization characteristics remaining in treated water after adsorption and synthesizing phosphorus adsorbent capable of magnetic separation for efficient removal of phosphorus. The synthesis of the adsorbent which set Zirconium(Zr) having high friendly features for phosphorus as an element, and by synthesizing Iron Oxide($Fe_3O_4$, another name of $Fe_3O_4$ is magnetite) being able to grant magnetism to Zirconium Sulfate($Zr(SO_4)_2$), zirconium magnetic adsorbent(ZM) were manufactured. In order to consider the phosphorus adsorption characteristics of adsorbent ZM, batch adsorption experiment was performed, and based on the results, pH effect, adsorption isotherm, adsorption kinetics, and magnetic separation have been explore. As the experiment result, adsorbent ZM showed a tendency that the adsorption number was decreased rapidly at pH 13; however, it was showed a high amount of phosphorus removal in other range and it showed the highest amount of phosphorus removal in pH 6 of neutral range. In addtion, the Langmuir adsorption isotherm model is matched well, and D-R adsorption isotherm model is ranged 14.43kJ/mol indicating ion exchange mechanism. The result shown adsorption kinetics match well to the Pseudo-second-order kinetic model. The adsorbent ZM's capablility of regenerating NaOH and $H_2SO_4$, was high selectivity on the phosphorus without impacts on the other anions. The results of applying the treated water after adsorption of phosphorus to the magnetic separation device by using permanent magnets, shows that capture of the adsorbent by the magnetization filter was perfect. And they show the possibility of utilization on the phosphorus removal in water.

• 공업화학
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• 제5권6호
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• pp.1024-1029
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• 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.

• 대한화장품학회지
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• 제45권2호
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• pp.105-116
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• 2019

두발이나 인체 세정 과정에서 일어나는 오일 흡착은 내부 성분량 변화와 컨디셔닝 기능에 큰 영향을 준다. 본 연구에서는 오일을 흡착재에서 직접 검출하여 편리하게오일량을 정량할 수 있는 흡수 분광 평가법을 개발하였다. 먼저, 오일 흡착량에 영향을 미치는 코아세르베이트 함량을 판단하기 위해서 음이온과 양쪽성 계면 활성제간 몰비율에 따른 코아세르베이트 함량을 조사하였다. 이 데이터를 활용하여 오일 흡착량 평가에 가장 적합한 오일 점도값을 확보하였고 세정제의 계면활성제간 몰비 조정 등을 통해 모발 대체 흡착재와 흡착 및 용출에 필요한 가장 최적의 방법을 확립하였다. 이렇게 확립한 평가법으로 자외선 흡광도가 있는 오일을 자외선 흡광도가 없는 실리콘 같은 오일 대신 배합해서 흡착시키고 용출시킨 후 흡수 분광법으로 오일 흡착량을 정량 계산해 본 결과를 HPLC의 질량분석과 AFM을 이용한 점착력 결과와 비교하였다. 오일 흡착에 영향을 미치는 요인인 양이온 폴리머를 다르게 하고 복합 폴리머를 사용해 본 결과 본 평가법이 모든 오일의 흡착량 평가에 적용할 수 있음을 입증하였다.

• 자원리싸이클링
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• 제12권3호
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• pp.13-24
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• 2003

폐호도껍질을 원료로 활성탄을 제조하는 과정에서 활성화 온도, 활성화 시간, 활성화제의 양, 그리고 활성화제의 종류 등을 변수로 하여 활성화 특성을 조사하였다. 인산을 활성화제로 사용하여 제조된 활성탄은 그 흡착능이 온도가 증가함에 따라 증가하여 약 $550^{\circ}C$부근에서 최대 흡착능을 보였으며 그 수율은 온도 상승에 따라 지속적으로 감소하였다. 활성화 시간은 약 2시간 정도에서 최적의 조건을 보였으며 시간이 증가함에 따라 활성탄의 수율은 계속 감소하였다. 활성화제의 농도 증가에 따라 수율은 지속적으로 상승하였으며 흡착능 또한 증대되다가 약 1.5M $H_3PO_4$ 이상의 조건에서는 오히려 흡착능이 감소하였다. SEM으로 관찰한 조건에 따른 활성탄의 미세구조의 변화는 조건별 흡착능의 변화와 잘 일치되었으며 활성화제의 종류는 활성화 과정에서 중요한 영향을 미치는 것으로 조사되었다. 제조된 활성탄의 흡착특성을 파악하기 위해 $Cu^{2+}$ 이온을 흡착질로 하여 흡착반응을 조사한 결과, 흡착반응은 전체적으로 2차식을 따르는 것으로 관찰되었으며 흡착질의 초기 농도가 감소함에 따라 반응상수는 점차 증가하였다. 평형흡착량은 Freundlich Model 을 잘 따르는 것으로 나타났으며 온도별 흡착반응을 검토한 결과, 중금속 이온의 흡착은 흡열반응의 특성을 나타내었다. 흡착에 따른 Activation Energy는 약 13.07kcal/mol로 산출되었으며 van't Hoff Equation을 이용하여 흡착반응의 열역학적 인자들을 계산하였다.