• Bulletin of the Korean Chemical Society
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• v.35 no.7
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• pp.1927-1928
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• 2014

• Carbon letters
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• v.9 no.1
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• pp.8-16
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• 2008

Oxidized activated carbons were prepared by reacting steam-activated carbon developed from pecan shells with nitric acid of varying strength (15, 30, 45 and 60%). The textural properties and the chemistry of the surface of the non-oxidized and of the oxidized carbons were determined from nitrogen adsorption and base neutralization capacities. The uptake of Pb(II) and Cd(II) from aqueous solution by these carbons was determined by kinetic and equilibrium experiments as well as by the column method. Treatment with nitric acid brought about drastic decrease in surface area and remarkable increase in the pore size of the carbon with these changes depending on the strength of nitric acid. Nitric acid increased the surface acidity by developing new surface oxygen functional groups of acidic nature. $HNO_3$-oxidized carbons exhibited high adsorption capacities for Pb(II) and Cd(II). The adsorption of these ions increased with the decrease of the surface pH of the carbon and with the increase of the solution pH from 2.5 to 6 and 7. The amount adsorbed from lead and cadmium was also related to the amount of surface acidity, the pH of the point of zero charge and on some metal ion parameters. Cadmium and lead uptake by the investigated carbons followed pseudo-second order model and the equilibrium sorption data fitted Langmuir adsorption model.

• Journal of the Ergonomics Society of Korea
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• v.15 no.2
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• pp.89-98
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• 1996

The objective of this study was to make comparison of the physical work capacities with different types and methods of tasks. To produce standard work loads, a bicycle ergometer and a treadmill were used for the purpose of two different types of tasks. Maximal oxygen uptake measurement tests are usually performen (1) continuously - with no rest between work load increments, or (2) discontinuously - with the subjects resting several minutes between work periods. Continuous test protocol with two different methods of work load increments, (1) ramp test- with 3 to 5 minutes of work period for each work load, and (2) incremental test - where exercise intensity was increased progressively in 2 minutes interval, were used. Predicted physicala work capacities (PWCs) were compared with the one by Kim(1990), and Lee(1995), and the NIOSH physiological criteria. For ergometer test, the PWC based on the ramp test was 89.65% of the one based on the incremental test. The PWC values were 2553.88 ml/min for the ramp test and 2848.82 ml/min for the incremental test. For treadmill test, the PWC based on the ramp test was 97.54% of the one based on the incremental test. The PWC values were 2786.89 ml/min for the ramp test and 2857.24 ml/min for the incremental test. The PWC obtained with a bicycle ergometer was 91.64% of the one obtained with a treadmill for the ramp test, and 99.71% for the incremental test.

• Carbon letters
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• v.10 no.4
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• pp.305-313
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• 2009

In this study, the adsorption of toxic pollutants onto cetyltrimethylammonium kaolin (CTAB-Kaolin) is investigated. The organo-kaolin is synthesized by exchanging cetyltrimethylammonium cations (CTAB) with inorganic ions on the surface of kaolin. The chemical analysis, the structural and textural properties of kaolin and CTAB-kaolin were investigated using elemental analysis, FTIR, SEM and adsorption of nitrogen at $-196^{\circ}C$. The kinetic adsorption and adsorption capacity of the organo-kaolin towards o-xylene, phenol and Cu(II) ion from aqueous solution was investigated. The kinetic adsorption data of o-xylene, phenol and Cu(II) are in agreement with a second order model. The equilibrium adsorption data were found to fit Langmuir equation. The uptake of o-xylene and phenol from their aqueous solution by kaolin, CTAB-kaolin and activated carbon proceed via physisorption. The removal of Cu(II) ion from water depends on the surface properties of the adsorbent. Onto kaolin, the Cu(II) ions are adsorbed through cation exchange with $Na^+$. For CTAB-kaolin, Cu(II) ions are mainly adsorbed via electrostatic attraction with the counter ions in the electric double layer ($Br^-$), via ion pairing, Cu(II) ions removal by the activated carbon is probably related to the carbon-oxygen groups particularly those of acid type. The adsorption capacities of CTAB-kaolin for the investigated adsorbates are considerably higher compared with those of unmodified kaolin. However, the adsorption capacities of the activated carbons are by far higher than those determined for CTAB-kaolin.

• Archives of Pharmacal Research
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• v.23 no.6
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• pp.620-625
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• 2000

The mechanisms of liver injury from cold storage and reperfusion are not completely under-stood. The aim of the present study was to investigate whether the inactivation of Kupffer cells (KCs) by gadolinium chloride ($GdCl_3$) modulates ischemia-reperfusion injury in the rat liver. Hepatic function was assessed using an isolated perfused rat liver model. In livers subjected to cold storage at $4^{\circ}C$ in University of Wisconsin solution for 24 hrs and to 20 min rewarm-ing ischemia, oxygen uptake was markedly decreased, Kupffer cell phagocytosis was stimulated, releases of purine nucleoside phosphorylase and lactate dehydrogenase were increased as compared with control livers. Pretreatment of rats with $GdCl_3$) , a selective KC toxicant, suppressed kupffer cell activity, and reduced the grade of hepatic injury induced by ischemia-reperfusion. While the initial mixed function oxidation of 7-ethoxycoumarin was not different from that found in the control livers, the subsequent conjugation of its meta-bolite to sulfate and glucuronide esters was suppressed by ischemia-reperfusion, CdCl$_3$restored sulfation and glucuronidation capacities to the level of the control liver. Our findings suggest that Kupffer cells could play an important role in cold/warm ischemia-reperfusion hepatic injury.