• Korean Chemical Engineering Research
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• 제61권1호
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• pp.97-108
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• 2023

Two carbonaceous adsorbents CAT and CARBOPAL were tested for reducing the concentration of the three herbicides in water: 2,4-D (2,4-dichlorophenoxyacetic acid), TCP (2,4,6-trichlorophenol) and metolachlor. Textural and chemical characterization of the adsorbents include nitrogen isotherms, FTIR, titration and thermogravimetric analyses. Adsorption was studied in discontinuous adsorption experiments at different pH values. The experimental adsorption isotherms data were fitted to four theoretical models. Adsorbent characterization reveals that CAT has higher micropore area, lower pore diameter and lower acidity than CARBOPAL. The adsorption is a second-order process and the isotherms best fitted to Sips model. The efficiency of the process depends mainly on the charge of the adsorbate for TCP and 2,4-D, but it depends on the charge of the surface for metolachlor. Adsorption capacity is higher on CAT for 2,4-D and TCP (small molecules), and it is higher on CARBOPAL for metolachlor (large molecules). Theoretical calculations clearly support this assumption.

• 상하수도학회지
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• 제37권6호
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• pp.395-408
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• 2023

This study presents a novel method for addressing the issue of high-concentration contaminants (ammonium, phosphate, antibiotics) in leachate arising from decomposing livestock carcasses. Antibiotics, developed to eliminate microorganisms, often have low biodegradability and can persist in the ecosystem. This research proposes design elements to prevent contamination spread from carcass burial sites. The adsorbents used were low-grade charcoal (an industrial by-product), Alum-based Adsorbent (ABA), and Zeolite, a natural substance. These effectively removed the main leachate contaminants: low-grade charcoal for antibiotics (initial concentration 1.05 mg/L, removal rate 73.4%), ABA for phosphate (initial concentration 2.53 mg/L, removal rate 99.9%), and zeolite for ammonium (initial concentration 38.92 mg/L, removal rate 100.0%). The optimal mix ratio for purifying leachate is 1:1:10 of low-grade charcoal, ABA, and zeolite. The average adsorbent usage per burial site was 1,800 kg, costing KRW 2,000,000 per ton. The cost for the minimum leachate volume (about 12.4 m³) per site is KRW 2,880,000, and for the maximum volume (about 19.7 m³) is KRW 4,620,000. These findings contribute to resolving issues related to livestock carcass burial sites and suggest post-management strategies by advocating for the effective use of adsorbents in leachate purification.

• Preventive Nutrition and Food Science
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• 제3권4호
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• pp.374-378
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• 1998

The objectives of this study are to determine the optimum process conditions of Korean beeswax and discuss the parameter of adsorption . Purification conditions, such as time, temperature and the type of adsorbents were investigated using the relationship between the properties of refined products and process conditions and theiptimum bleaching condition of Korean beeswax were determined for the first time. The various bleaching conditions were examined by observing the result of Lovibond color, photometric color, methods provided by the American Oil Chemists '(A.O.C.S).The iptimum bleaching temperature was 8$0^{\circ}C$ and the bleaching agents (5% of the weight of beeswax) which consisted of activated clay and activated carbon and a vacuum system were also necessary.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1997년도 Proceedings of the 12th KACG Technical Meeting and the 4th Korea-Japan EMGS (Electronic Materials Growth Symposium)
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• pp.67-71
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• 1997

Activated carbons are the microporous carbonaceous adsorbents which are prepared from carbon-containing source materials such as wood, coal, lignite, peteroleum and sometimes synthetic high polymers. [1-2] Activated carbons shows an ability to adsorbe hydrocarbons of the gas phase. Activated carbons are used in the purification of many kinds of gas phases like hexane, benzene, toluene, gasoline, phenol etc.[3] In this study, cokes from bitminous coal were activated for the purpose of preparing the activated carbons by steam activation. The effect of the activation temperature, time, steam concentration and flow rate on the n-butane adsorption, burn off, surface area and average pore size of the activated carbons, were investigated. The adsorption characteristics of the activated carbons for gasoline are indirectly estimated by n-butane adsorption.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.568-573
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• 2011

Carbon dioxide concentration of railroad passenger cabin is obliged to be kept lower than guideline values of 'Indoor air quality guideline for public transportations', but actual carbon dioxide concentration frequently exceeds this guideline value. Ventilation is most desirable to lower carbon dioxide concentration but there are some cases when the ventilation is not applicable. In this study, carbon dioxide concentration control method using adsorbents was presented. The cation of zeolites were exchanged with various kinds of cations, and the carbon dioxide adsorption performance of the zeolites were studied. The various kinds of cations, solvents, and zeolites were introduced, and it was found that some cation-exchanged zeolites showed good carbon dioxide adsorption performances. It is expected that the obtained results will be used to lower carbon dioxide concentration of railroad passenger cabin.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.138-141
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• 2011

Carbon dioxide concentration of railroad passenger cabin is obliged to be kept lower than guideline values of 'Indoor air quality guideline for public transportations', but actual carbon dioxide concentration frequently exceeds this guideline value during the morning and evening rush hours. For improving comfortability and satisfaction of passengers, concentration control method using $Al_2O_3$ adsorbents was presented. The adsorbent is made from $Al_2O_3$ and LiOH. $Al_2O_3$ perform as a frame and LiOH as a chemical adsorbent. The adsorbent performance experiment was carried out by measuring concentration change of Carbon dioxide in terms of flow, initial concentration and amount of adsorbent. It is expexted that the obtained results will be used to lower carbon dioxide concentration of railroad passenger cabin.

• 한국대기환경학회지
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• 제9권1호
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• pp.101-106
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• 1993

In order to separate the Freon-12 and air mixture$(CF_2Cl_2/Air=0.1/99.9 vol.%)$ by pressure swing adsorption (PSA), the breakthrough curve was experimentally observed in a fixed bed adsorption column. A single adsorber was packed with various adsorbents such as, the activated carbon(S-AC, W-AC) and the molecular sieve(MS-5A, MS-13X). The order of appearance of breakthrough curve is MS-5A > MS-13X > W-AC > S-AC. The activated carbon was found to be more effective adsorbent for separating Freon-12 from the mixture than the molecular sieve was. From the experimental data obtained by the separation of Freon-12 gas out of the air stream in the steady-state PSA process cycle, whose size is the same one of column used for the breakthrough curve observation, it has been confirmed that Freon-rich gas could be obtained from the purge step of PSA and Freon-free air could be obtained from the adsorption step of PSA cycle.

• 약학회지
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• 제39권4호
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• pp.395-400
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• 1995

The sorption and desorption properties of four adsorbents were evaluated for the trace enrichment of clobazam from biological samples. Graphitized carbon black(GCB) gaved the highest dynamic adsorption coefficient. Among the six organic solvents examined, acetone gave the highest desorption coefficient for the clobazam adsorbed on GCB. Using the GCB column, the optimum elution volume of the eluting solvent was evaluated from the on-line monitored breakthrough curve for clobazam. When GCB as the solid adsorbent and acetone as the eluting solvent were used for the solidphase extraction of clobazam from serum, the recoveries were higher than 83% with good reproducibility in the concentration range of 20-50 $\mu\textrm{g}$/ml.

• 한국환경과학회지
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• 제2권4호
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• pp.357-365
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• 1993

This study was conducted for the efficient utilization of biomaterials such as starch residue, tangerine skin, and green tea residue, which are agricultral by-products discarded in Cheju Province annually, as adsorbents and biomaterials were examined for their removal ability of heavy metal ions in waste water by batch adsorption experiments. The removal efficiency of biomaterials for heavy metal ions was above 80-90% and almost similar to activated carbon and the adsorption ability of those treated with 포르말린 was improved in the green tea residue only for $Pb^{2+}$, $Cu^{2+}$, and $Zn^{2+}$. In the conditions of pH, the removal efficiency of heavy metal ions was high in the range of 5-7. In the solutions which heavy metal ions were mixed, the removal efficiency was similar at $Ag^+$, $Pb^{+2}$ and reduced to about 10% at the other ions, as compared with the solutions they were not mixed. Adsorption isotherm of biomaterials was generally obeyed to Freundlich formular than Langmuir formular and Freundlich constant, 1/n were obtained in the range of 0.1-0.5.

• 한국환경보건학회지
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• 제24권3호
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• pp.87-91
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• 1998

The removal effect of phosphate by sludge from wastewaters prior to discharge into natural waters is an essential measure to prevent eutrophication in receiving waters. There is need for developing low cost, easily and abundantly available, efficient adsorbents for the removal of phosphorus (P as orthophosphate) during the tertiary treatment of wastewaters. The adsorbent carbon which is prepared with fisheries wastes on a laboratory scale has been used to evaluate its performance for phosphate adsorption. Phosphate removal increase with increasing adsorbent dose and temperature, but shows no changes at an adsorbent dose over 8 g/l.