• Economic and Environmental Geology
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• v.39 no.2 s.177
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• pp.103-109
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• 2006

Batch adsorption experiments were performed to adsorb cadmium [Cd(II)], copper [Cu(II)], and lead [Pb(II)] onto sphagnum peat moss. According to the results, 10-50 mg/L of Cd(II), Cu(II), and Pb(II) were effectively adsorbed and removed within 1 h by 1.0 g/L of sphagnum peat moss. The amounts of Cd(II), Cu(II), and Pb(II) adsorbed on sphagnum peat moss increased with increasing the initial concentrations. The kinetics for the adsorption of Cd(II), Cu(II), and Pb(II) on sphagnum peat moss was described well using the pseudo-second order model at different initial concentrations. The maximum adsorption capacities calculated from the Langmuir isotherm for Cd(II), Cu(II), and Pb(III) were 33.90, 29.15, and 91.74 mg/g, respectively. Experimental results showed that sphagnum peat moss was a very effective adsorbent on the adsorption of Cd(II), Cu(II), and Pb(II).

• Analytical Science and Technology
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• v.21 no.4
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• pp.326-331
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• 2008

Distribution coefficients (Kd) of uranyl ion onto divinylbenzene amidoxime resins were measured in sodium carbonate solution and the Kd values were increased up to about 70 as the resin bead size was decreased. At a condition of 0.0044 M $Na_2CO_3$, the adsorption capacity for uranium was $3.4{\mu}mole$ U/g-resin. The Kd values in the 0.5 M $Na_2CO_3-NaHCO_3$ solution, ranging from pH 9 to pH 11, revealed that they were increased as the pH increased and revealed lower values than those in the pure sodium carbonate solution. The amidoxime resins were characterized by FTIR-ATR showing the absorption bands of the amidoxime functional groups. A species of the uranyltricarbonate complex, $UO_2(CO_3)_3^{-4}$, was confirmed by UV-Vis spectroscopy, revealing four absorption peaks between 400 and 500 nm. Uranium was separated from some fission products by a column operation. However, most of the uranium and fission products were eluted before an adsorption and only a small amount of uranium was adsorbed onto the resin due to the low capacity of the resin.

• Applied Chemistry for Engineering
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• v.19 no.5
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• pp.533-538
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• 2008

In order to enhance the adsorption capacity of $CO_2$, a commercial zeolite and coal fly ash were chemically modified with alkali cations (Li, K) and alkaline-earth cations (Ca, Mg). Adsorbents containing Ca and Mg showed slightly lower surface areas. The adsorption capacity at the ambient temperature was highest with Ca, then in order of Mg, Li, and K. On the contrary, regeneration efficiency of the adsorbents with Ca and Mg was relatively low, because Ca and Mg cations had stronger affinity of carbon dioxide. The affinity between cations and $CO_2$ molecule also may improve the selectivity in favor of $CO_2$ adsorption.

• Analytical Science and Technology
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• v.12 no.2
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• pp.159-165
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• 1999

The adsorption and separation behaviors of transition metal ions using a merrifield resin bound 1,12-diaza-3,4:9,10-dibenzo-5,8-dioxacyclopentadecane (NTOE) and 1,12,15-triaza-3,4:9,10-dibenzo-5,8-dioxacycloheptadecane(NDOE) were investigated in aqueous solution. The orders of adsorption degree(E) and distribution ratio(D) of transition metal ions were Cu(II)$t_R$) of metal ions were affected by adsorption degree(E) and distribution ratio(D). This results showed good separation efficiency of Ag(I) from mixed metal solution.

• Horticultural Science & Technology
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• v.19 no.2
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• pp.174-178
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• 2001

Absorption potential of oak charcoal was estimated using simulated static and dynamic systems to establish a model for practical application of the charcoal in modified atmosphere (MA) packaging and during the storage of 'Fuji' apples. Practical MA packaging was performed using $60{\mu}m$ PE film zipper bags in which five apples were placed. Absorption potential of oak charcoal was $58.4{\mu}L/100g$ charcoal for ethylene and 583 mg/100 g charcoal for carbon dioxide. Effects of enclosing a 100 g-charcoal packet inside a MA package seemed not to last long enough for quality maintenance of 'Fuji' apples stored at $0^{\circ}C$ for three months. During extended storage, ethylene and $CO_2$ levels were not significantly reduced by charcoal treatment. Nevertheless, absorption of carbon dioxide appeared to alleviate the incidence of $CO_2$-related internal browning disorder. Modelling study of practical storage and marketing procedure indicates that 0.19 kg charcoal/day is required to offset $CO_2$ production from 15 kg of apples at $0^{\circ}C$. The amount of charcoal should be increased to 3.10 kg/day if ethylene is a target gas. From the practical point of view, the results suggest that charcoal could be used only for small unit packages for a short period.

• Applied Chemistry for Engineering
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• v.1 no.2
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• pp.215-223
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• 1990

The effects of sulfur on the catalytic reaction between CO and NO on polycrystalline Pt surface, which is very important in the development of catalyst for automobile exhaust gas control, have been studied using thermal desorption spectrometry(TDS) under ultra-high vacuum(UHV) conditions. Sulfur weakened both the adsorptions of CO and NO by direct site blocking and indirect electronic effect. S(a) desorbing below 800 K gave little effect on reaction activity whereas S(a) desorbing above 800 K, which adsorbs as an atomic state, gave much effect on it. The adsorbed sulfur existed on the surface of platinum in the form of islands, and also reduced the adsorption energies of adsorbates by the long-ranged electronic effect. The platinum catalyst in the reaction between CO and NO was poisoned selectively by S(a), poisoning firstly the active sites of this reaction.

• Applied Chemistry for Engineering
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• v.22 no.5
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• pp.555-561
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• 2011

The objective of this study is the development of carbon recycle technology which converts $CO_2$ captured from flue gas to CO or carbon and reuse in industrial fields. Since $CO_2$ is very stable and difficult to decompose, metal oxide was used as an activation agent for the decomposition of $CO_2$ at low temperature. Metal oxides which convert $CO_2$ to CO or carbon at $500^{\circ}C$ were prepared using Zn-ferrite by the solid state reaction and hydrothermal synthesis. The behaviors of $CO_2$ decomposition were studied using temperature programmed reduction/oxidation (TPR/TPO) and thermogravimetric analyzer (TGA). Zn-ferrite containing 5 wt% ZnO showed the largest reduction and oxidation. Reduction by $H_2$ was 26.53 wt%, oxidation by $CO_2$ was 25.73 wt% and 96.98% of adsorbed $CO_2$ was decomposed to $CO_2$ and carbon with excellent oxidation-reduction behaviors.

• Polymer(Korea)
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• v.24 no.1
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• pp.1-7
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• 2000

The ACF/PP-g-AAc copolymers were synthesized by the irradiational grafting of acrylic acid onto ACF/PP fabric. The synthesis of copolymer was evidenced by the bands at 1720, 3600~3100 $cm^{-1}$ / on FT-IR spectrum. After the adsorption of metal ions on ACF/PP-g-AAc copolymers, the morphology with the small deposits on the fiber surface were observed by SEM. The optimal time for the metal ion adsorption equilibrium on ACF/PP-g-AAc copolymers was 24 hrs and their adsorption capacities increased in the order of Mn$^{2+}$>Cu$^{2+}$>Co$^{2+}$>Ni$^{2+}$. The adsorption capacities of ACF/PP-g-AAc copolymers were invariable after more than 10 times of regeneration.eration.

• Korean Journal of Materials Research
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• v.8 no.2
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• pp.120-125
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• 1998

CO$_{2}$gas중에서 산화된 활성탄소섬유를 77K에서 질소흡착에 의해 흡착등온곡선을 구하였다. 미세공부피와 외부표면적은 t-법으로 구하였으며, 평균기공크기와 기공분포는 Dubinin-Astakhov법으로 구하여 기공발당과정을 고찰하였다. 산화반응 초기(약 40% burn-off까지)에 섬유내부에 발달하는 미세공은 burn-off가 40%를 넘으면 서서히 큰 미세공으로 성장하며, burn-off가 약 60%이상되면 미세기공은 확대 또는 합체되어 점차 중기공으로 성장하는 것으로 관찰되었다. 또한 고온산화반응으로 발달한 기공은 저온에서 생성된 기공보다 크다.

• Economic and Environmental Geology
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• v.51 no.2
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• pp.99-111
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• 2018

In this study three target radionuclides ($^{60}Co$, $^{137}Cs$, and $^{125}Sb$) were reacted with solid samples collected from the nuclear facility sites to investigate their sorption and mobility behaviors for preparing unexpected nuclear accidents. The highest sorption distribution coefficients ($K_{ds}$) of target radionuclides ($^{60}Co=947mL/g$, $^{137}Cs=2105mL/g$, $^{125}Sb=81.3mL/g$) were found in topsoil layer under groundwater condition, and the $K_d$ values of three radionuclides decreased in the order of fractured rock and bedrock samples under the same groundwater condition. High $K_d$ values of $^{60}Co$ in topsoil layer and fracture rock resulted from the clay minerals present, and the $K_d$ values decreased 58-69 % under seawater condition due to high ionic strength. $^{137}Cs$ sorption was controlled by the ion exchange reaction with $K^+$ on flayed edge sites (FES) of mica. The $^{137}Cs$ sorption was the most affected by seawater (89-97 % decrease), while $^{125}Sb$ sorption was not much affected by seawater. As the results of column and batch experiments, the retardation factors (R) of $^{137}Cs$, $^{60}Co$, and $^{125}Sb$ were determined about 5400-7400, 2000-2500, and 250-415, respectively, indicating no significant transport for these radionuclides even in fractured zone with groundwater. These results suggest that even in the case of severe nuclear accident at the nuclear facilities the mobility of released radionuclides ($^{60}Co$, $^{137}Cs$, and $^{125}Sb$) can be significantly retarded by the topsoil layer and fractured rock. In addition, the results of this study will be used for the safety and environmental performance assessment of nuclear facilities.