• Journal of the Korean Chemical Society
• /
• v.54 no.5
• /
• pp.533-540
• /
• 2010

An activated carbon was tested for its ability to remove transition metal ions from aqueous solutions. Physical, chemical and liquid-phase adsorption characterizations of the carbon were done following standard procedures. Studies on the removal of Ni(II), Cu(II) and Fe(III) ions were attempted by varying adsorbate dose, pH of the metal ion solution and time in batch mode. The equilibrium adsorption data were fitted with Freundlich and Langmuir and the isotherm constants were evaluated, equilibrium time of the different three metal ions were determined. pH was found to have a significant role to play in the adsorption. The processes were endothermic and the thermodynamic parameters were evaluated. Desorption studies indicate that ion-exchange mechanism is operating.

• Korean Journal of Materials Research
• /
• v.9 no.8
• /
• pp.798-803
• /
• 1999

This study has been focused on the influence of Fe(III) incorporation into framework of SAPO-34(FeAPSO-34s;/su/Fe = 40,20 and 5) on the catalytic performance of methanol conversion. By rapid crystallization method, the XRD,SEM,ICP,TG-DTA, and BET sufrace areas. With an increase in the Fe content incorporated to the framework, the crystallinity identified from the intensity of XRD peaks slightly decreased and the particle size observed from SEM photographs decreased also. On the other hand, the acid sites in crystal decreased kin the Fe-incorporated samples, and the selectivity to ethylene for FeAPSO-34 catalyst on methanol conversion was enhanced compared with the nonmetal incorporated(SAPO-34)

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.285-285
• /
• 2013

수산화인회석(Hydroxyapatite, HAP)은 인체 내 뼈와 치아의 주성분으로서 칼슘과 인산염으로 구성된 물질이다. 암모늄을 이용하여 pH를 조절함으로서 hexagonal 형태의 HAP를 수열합성법으로 합성하였다. XRD pattern을 통하여 수산화인회석의 결정구조를 확인하였으며, 전이금속 중의 하나인 Fe(III) 이온을 이온교환반응을 통하여 수산화인회석 표면에 도입하였다. ICP 측정을 통해 Fe 함량을 정량하였고 SEM과 TEM image를 통하여 크기와 형태를 관찰하였다.

• Journal of Korea Soil Environment Society
• /
• v.4 no.2
• /
• pp.11-31
• /
• 1999

Removal of hexavalent chromium from artificial groundwater (AGW) by granular activated carbon (GAC) was investigated in batch and continuous-flow column studies. Experimental parameters that were examined included solution pH, presence of dissolved oxygen (DO), and GAC pretreatment with Fe(II). As the solution pH increased from 4 to 7.5, the amount of Cr(VI) removed by both GACs decreased significantly. Exclusion of DO from the experimental systems resulted in greater removal of Cr(VI) from solution, possibly as a result of reduction to Cr(III). However, pretreatment of the GAC with a reductant (Fe(II)) did not improve Cr(VI) removal. Equilibration With 0.01 M $K_2$$HPO_4$[to extract adsorbed Cr(VI)] followed by a wash with 0.02 N $K_2$$HPO_4$[to remove precipitated/sorbed Cr(III)] proved to be a viable approach for the regeneration of carbons whose Cr(VI) removal capacities had been exhausted. The performance of the regenerated carbons exceeded that of the virgin carbons, primarily because of the favorable adsorption of Cr(VI) at lower pH values and the reduction of Cr(VI) to Cr(III), The presence of Cr(III) in acid wash solutions provides direct evidence that Cr(VI) is reduced to Cr(III) in GAC systems under relatively acidic conditions. GAC performance over five complete cycles was consistently high, which suggests that such a system will be able to function over many operation cycles without deleterious effects.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.27 no.6
• /
• pp.625-633
• /
• 2014

Mark III CCS plate is considered in this paper to perform its strength assessment. Mark III CCS plate is designed and constructed by stacking various non-metallic engineering materials such as plywood, triplex and reinforced PU foam that are supported by series of mastic upon inner steel hull structure. From the viewpoint of structural analysis, this plated structure is treated as a laminated anisotropic structure. Commercially available general purpose finite element analysis programs such as MSC PATRAN and MARC are used to develop the finite element (FE) model of the Mark III CCS plate. Because of the characteristics of LNG cargo that the Mark III CCS plate deals with, it is subjected to a wide range of temperature variations, i.e. about $-163^{\circ}C$ to $20^{\circ}C$. Different material properties of the Mark III CCS plate at these temperature levels are considered in the FE model. Using the developed FE model, strength assessment procedure is developed incorporating various anisotropic failure criteria such as Hashin, Hill, Hoffman, Maximum stress and Tsai-Wu. The strength assessment is performed within the initial failure state of the Mark III CCS plate and, as a result, failure details such as failure locations and loads are identified.

• Journal of the Korean Chemical Society
• /
• v.33 no.6
• /
• pp.662-668
• /
• 1989

The decomposition reaction of hydrogen peroxide was carried out by using metal-4,4',4",4"'-tetraaminophthalocyanine [Mt-$PcNH_2$, Mt = Fe(III), Co(II)] supported on poly (styrene-co-methacrylic acid), in heterogeneous aqueous system. These catalysts showed a catalse-like activity and Fe(III)-$PcNH_2$ supported on the copolymer was particularly effective for the decomposition of hydrogen peroxide. It was found that the rate of decomposition increased smoothly in the higher pH region and catalytic reaction was interfered by adding $CN^-,\;CNS^-,\;{C_2O_4}^{-2},\;I^-$ ions. The kinetics of the catalytic reaction was also investigated and the reaction proceeds according to the Michaelis-Menten type mechanism.

• KSBB Journal
• /
• v.9 no.3
• /
• pp.279-286
• /
• 1994

A mathematical model has been derived and used to describe phosphoprotein partitioning in Fe(III) IDA-PEG/dextran two-phase systems. This model includes the inhibitory effects of hydrogen and hydroxyl ion concentrations on protein partitioning. For aqueous two-phase partitioning experiments, the Al and A2 subcomponents of ovalbumin carrying two and one surface phosphoryl group(s) were purified using an immobilized metal ion affinity chromatography (IMAC). The ratio of partition coefficients in the presence and absence of Fe(III)IDA-PEG, K/Ko, increased in the pH range of 3.0 to 5.0 due to deprotonation of the second oxygen of the phosphoryl group, and above pH 5.0 declined steeply by the inhibitory binding of hydroxyl ions to the metal ion. This partitioning behavior was well described by the mathematical model. The binding constants for formation of the complex between the phosphoryl group and the Fe(III)IDA-PEG were found to be $6.1{\times}10^3M^{-1} and 2.3{\times}10^4M^{-1}$ in the top and bottom phases, respectively. These values are 3-5 times those for interaction of Cu(II)IDA-PEG with a single surface-accessible histidine.

• Analytical Science and Technology
• /
• v.10 no.6
• /
• pp.427-432
• /
• 1997

A selective method for the determination of iron(III) ion with a sodium dodecyl sulfate(SDS) modified glassy carbon electrode was proposed. It was based on the electrostatic attraction and complexation of the SDS modifier, $(DS^-)_n-Fe^{3+}$. The determination of iron(III) ion was performed by a differential pulse voltammetry(DPV), and the reduction peak potential of $(DS^-)_n-Fe^{3+}$ was +0.466(${\pm}0.002$)V vs. Ag/AgCl. For the determination of iron(III) ion, a linear calibration curve was obtained within the iron(III) ion concentration range of $0.50{\times}10^{-5}{\sim}10{\times}10^{-5}mol/L$, and the detection limit was $0.14{\times}10^{-5}mol/L$. $Cu^{2+}$, $Ni^{2+}$, $Co^{2+}$, $Pb^{2+}$, $Zn^{2+}$, and $Mn^{2+}$ showed little or no effect on the determination of iron(III) ion, respectively. But, ion such as each $CN^- $ and $SCN^-$ interfered seriously.

• Journal of Microbiology and Biotechnology
• /
• v.31 no.11
• /
• pp.1519-1525
• /
• 2021

Hexavalent chromium (Cr(VI)) is recognized to be carcinogenic and toxic and registered as a contaminant in many drinking water regulations. It occurs naturally and is also produced by industrial processes. The reduction of Cr(VI) to Cr(III) has been a central topic for chromium remediation since Cr(III) is less toxic and less mobile. In this study, fermentative Fe(III)-reducing bacterial strains (Cellu-2a, Cellu-5a, and Cellu-5b) were isolated from a groundwater sample and were phylogenetically related to species of Cellulomonas by 16S rRNA gene analysis. One selected strain, Cellu-2a showed its capacity of reduction of both soluble iron (ferric citrate) and solid iron (hydrous ferric oxide, HFO), as well as aqueous Cr(VI). The strain Cellu-2a was able to reduce 15 μM Cr(VI) directly with glucose or sucrose as a sole carbon source under the anaerobic condition and indirectly with one of the substrates and HFO in the same incubations. The heterogeneous reduction of Cr(VI) by the surface-associated reduced iron from HFO by Cellu-2a likely assisted the Cr(VI) reduction. Fermentative features such as large-scale cell growth may impose advantages on the application of bacterial Cr(VI) reduction over anaerobic respiratory reduction.

• Journal of the Korean Chemical Society
• /
• v.12 no.2
• /
• pp.47-50
• /
• 1968

Two methods for separation of the impurities from bismuth metal have been found by the use of Dowex $1{\times}4,$ anion exchange resins. The first method is that Dowex $1{\times}4$ resins are packed into the two stage columns (height of under stage is 22cm and upper stage is 3cm, and diameter of columns are 1.5cm), and the impurities of Pb(II), Ag(I) and Cu(II) are separated by the eluent of 7.5M HCl soln, Zn(II), Fe(III) by 0.5M HCl solns, and Te(IV) in the upper stage by 2M NaOH soln. Remained Au(III) in the upper stage is determined by the ignition with resins. The 2nd method is that for the separation of all the impurities simultaneously the same resins are packed into single stage column(height is 10cm and diameter is 1.5cm), and all the impurities of Pb(II), Zn(II), Cu(II), Fe(III) and Ag(I) are eluted by the eluent of 0.5M HCl soln. Separated impurities are determined by the colorimetry.