• Advances in environmental research
• /
• v.2 no.3
• /
• pp.167-177
• /
• 2013

We investigated that removal of aqueous U(VI) by nano-sized Zero Valent Iron (nZVI) and Fe(II) bearing minerals (controls) in this study. Iron particles showed different U(VI) removal efficiencies (Mackinawite: 99%, green rust: 95%, nZVI: 91%, magnetite: 87%, pyrite: 59%) due to their different PZC (Point of Zero Charge) values and surface areas. In addition, noticeable amount of surface Fe(II) (181 ${\mu}M$) was released from nZVI suspension in 6 h and it increased to 384 ${\mu}M$ in the presence of U(VI) due to ion-exchange of U(VI) with Fe(II) on nZVI surface. Analysis of Laser-Induced Breakdown Detection (LIBD) showed that breakdown probabilities in both filtrates by 20 and 200 nm sizes was almost 24% in nZVI suspension with U(VI), while 1% of the probabilities were observed in nZVI suspension without U(VI). It indicated that Fe(II) colloids in the range under 20 nm were generated during the interaction of U(VI) and nZVI. Our results suggest that Fe(II) colloids generated via ion-exchange process should be carefully concerned during long-term remediation site contaminated by U(VI) because U could be transported to remote area through the adsorption on Fe(II) colloids.

• Journal of Environmental Health Sciences
• /
• v.27 no.3
• /
• pp.107-112
• /
• 2001

This work reports the application of a hollow fiber module(HFM) for Cr(VI) extraction from heavy metal salts mixed solution by using microporous hydrophobic hollow fiber module. In HFM configuration, the organic extraction used for the extraction of Cr(VI) was di-(2-ethyl hexyl) phosphoric acid(D2EHPA) diluted with n-heptane. The study of HFM includes the influence of hydrodynamic and chemical condition, i.e., the flow rate of feed solution, the time of reactive extraction, the concentration of feed solution, and the pH of aqueous phase solutions. Several experiments with synthetic solution of different mixed components system of Cr(VI) solutions established optimum condition to achieve a clean separation of Cr(VI). It was possible to separate Cr(VI) in the presence of metal salts mixed solution, such as Zn(II), Ni(II), Cu(II), and Cd(II) using the HFM technique.

• Journal of Korean Society of Environmental Engineers
• /
• v.30 no.7
• /
• pp.729-734
• /
• 2008

The higher valence state of iron i.e., Fe(VI) was employed for the treatment of Cu(II)-EDTA in the aqueous/waste waters. The ferrate(VI) was prepared through wet oxidation of Fe(III) by sodium hypochlorite. The purity of prepared Fe(VI) was above 93%. The stability of Fe(VI) solution decreased as solution pH decreased through self decomposition. The reduction of Fe(VI) was obtained by using the UV-Visible measurements. The dissociation of Cu(II)-EDTA complex through oxidation of EDTA using Fe(VI) and subsequent treatment of organic matter and metal ions by Fe(III) reduced from Fe(VI) in bench-scale of continuous flow reactor were studied. The removal efficiencies of copper were 69% and 79% in pH control basin and reactor, respectively, at 120 minutes as retention time. In addition, Cu(II)-EDTA in the reactor was decomplexated more than 80% after 120 minutes as retention time. From this work, a continuous treatment process for the wastewater containing metal and EDTA by employing Fe(VI) as muluti-functional agent was developed.

• The Bulletin of The Korean Astronomical Society
• /
• v.43 no.2
• /
• pp.39.2-39.2
• /
• 2018

RR Tel is an interacting binary system in which a hot white dwarf (WD) accretes matter from a Mira variable via gravitational capture of the stellar wind. We present a high-resolution optical spectrum of RR Tel obtained with MIKE at Magellan-Clay telescope, Chile. We find broad emission features at 6825, 7082, 7023, and $7053{\AA}$, which are formed through Raman scattering of far-UV O VI ${\lambda}{\lambda}$ 1032 and $1038{\AA}$, C II ${\lambda}{\lambda}$ 1036 and $1037{\AA}$ with atomic hydrogen. Raman O VI 6825 and 7082 features are characterized by double-peaked profiles indicative of an accretion flow with a characteristic speed ~ 30km/s, whereas the Raman C II features exhibit a single Gaussian profile with FWHM ${\sim}10{\AA}$. Monte Carlo simulations for Raman O VI and C II are performed by assuming that the emission nebula around the WD consists of the inner O VI disk with a representative scale of 1 AU and the outer part with C II sphere. The best fit for Raman profiles is obtained with an asymmetric matter distribution of the O VI disk, the mass loss rate of the cool companion ${\dot{M}}{\sim}2{\times}10^{-6}M_{{\odot}/yr}$ and the wind terminal velocity v~10 km/s. We also find O VI doublet at 3811 and $3834{\AA}$, which are blended with other emission lines. Our profile decomposition shows that the O VI ${\lambda}{\lambda}$ 3811, 3834 doublet have a single Gaussian profile with a width ~ 25 km/s. A comparison of the restored fluxes of C II ${\lambda}{\lambda}$ 1036 and 1037 from Raman C II features with the observed C II ${\lambda}1335$ leads to an estimate of a lower bound of N(CII) > $9.87{\times}10^{13}cm^{-2}$ toward RR Tel, which appears consistent with the presumed distance D ~ 2.6 kpc.

• Journal of Life Science
• /
• v.7 no.1
• /
• pp.39-48
• /
• 1997

Cigarette is the risk factor of Lung cancer, chronic obstructive pulmonary disease and ischemic heart disease. So I have studied the effect of Macmoondongtang in rat exposed to cigarette smoke. Thirty-six healthy rat subjects were divided into 6 groups-the control group(sample I), the groups of administration of Platycodi Radix(sampleII), Adenophorae Radix(sampleIII), Liriopsis Tuber(sampleIV), Maximowicziae Fructus(sample V) and Macmoondongtang(sample VI), and expose to cigarette per day for 12 days. 1. On level of leckocyte are significant all the group of sampleII, sampleIII, sample IV, sample V, sample VI on 6th day and singificant the groups of sampleIV, sample V on 12th day. 2. On level of hemoglobin are singificant the groups of sample IV, sample V, sample VI, on 6th day, and significant sample II, sample III, sample IV, sample V, sample VI on 12th day. 3. On platelet level are significant all the group of sampleII, sample III, sample IV, sample V, sample VI on 12th day. 4. On SOD activity are significant all the groups of sample IV, sample VI, on 6th day, and significant sampleII, sample III, sample VI on 12th day. According to the results, Macmoondogtang is effective to risk of cigarette smoke.

• Environmental Engineering Research
• /
• v.20 no.1
• /
• pp.89-97
• /
• 2015

Remediation of wastewater contaminated with metal(II)-complexed species (Cu(II)-NTA (NTA: nitrilotriacetic acid), Cu(II)-EDTA (EDTA: ethylenediamine tetraacetic acid) and Cd(II)-EDTA is attempted using the potential applicability of ferrate(VI). Kinetics of pollutant degradation is obtained with the removal of ferrate(VI) studied at wide range of pH (8.0-10.0) and the concentration of metal(II)-complexed species (0.3 to 15.0 mmol/L) employing a constant dose of ferrate(VI) i.e., 1.0 mmol/L. Pseudo-first-order and pseudo-second-order rate constants were obtained in the reduction of ferrate(VI) which was then employed to obtain the overall rate constants of the pollutant degradation. The mineralization of NTA and EDTA was obtained with the change in TOC (total organic carbon) values collected by the ferrate(VI) treated pollutant samples. Decrease in pH and molar pollutant concentrations was greatly favored the percent mineralization of NTA or EDTA by the ferrate(VI) treatment. The treated pollutant samples were filtered and subjected for AAS (atomic absorption spectrophotometric) analysis to assess the simultaneous removal of copper and cadmium from aqueous solutions at the studied pH as well at the elevated pH 12.0. Results show that an enhanced removal of cadmium or copper was achieved at pH 12.0. Overall, ferrate(VI) possesses multifunctional application in wastewater treatment as it oxidizes the degradable impurities and removes metallic impurities by coagulation process.

• 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.

• Analytical Science and Technology
• /
• v.10 no.4
• /
• pp.282-290
• /
• 1997

The sorption and desorption properties of U(VI), Th(IV), Zr(IV), Cu(II), Pb(II), Ni(II), Zn(II), Cd(II) and Mn(II) ions on XAD-16-[4-(2-thiazolylazo)orcinol] (TAO) chelating resin were studied by elution method. The effect was examined with respect to overall capacity of each metal ion, separation of mixed metal ions, flow rate and concentration of buffer solution for optimum condition of sorption. The overall capacities of some metal ions on this chelating resin were 0.35nmol U(VI)/g resin, 0.49nmol Th(IV)/g resin, 0.41nmol Cu(II)/g resin, and 0.31nmol Zr(IV)/g resin, respectively. The elution order of metal ions obtained from breakthrough capacity and overall capacity at pH 5.0 was Th(IV)>Cu(II)>U(VI)>Zr(IV)>Pb(II)>Ni(II)>Zn(II)>Mn(II)>Cd(II). The group separation of mixed metal ions was possible by increasing pH in pH range 2~5 at a flow rate of 0.28mL/min. Characteristics of desorption were investigated with desorption agents such as $HNO_3$, HCl, $HClO_4$, $H_2SO_4$, and $Na_2CO_3$. It was found that 2M $HNO_3$ showed high desorption efficiency to most of metal ions except Zr(IV) ion. Also, desorption and recovery of Zr(IV) ion were successfully performed with 1M $H_2SO_4$. Recovery of trace amount of U(VI) ion from artificial sea water was over 94%. The chelating resin, XAD-16-TAO was successfully applied to group separation of rare earth metal ions from U(VI) by using 2M $HNO_3$ as an eluent.

• Analytical Science and Technology
• /
• v.17 no.3
• /
• pp.199-210
• /
• 2004

A new polystyrene-divinylbenzene chelating resin containing 4,5-dihydroxy-naphthalene-2,7-disulfonic acid (chromotropic acid : CTA) as functional group has been synthesized and characterized. The sorption and desorption properties of this chelating resin for Cr(III) ion and Cr(VI) ion including nine metal bloodstain. As a results, FOB test kit could be effectively applied to identification of human blood at chelating resin was stable in acidic and alkaline solution. The Cr(VI) ion is selectively separated from Cr (III) ion at pH 2 and the maximum sorption capacity of Cr(VI) ion is 1.2 mmol/g. In the presence of anions such as $F^-$, $SO{_4}^{2-}$, $CN^-$, $CH_3COO^-$, $NO{_3}^-$, the sorption of Cr(VI) ion was reduced but anions such as $PO{_4}^{3-}$ and $Cl^-$ revealed no interference effect. The elution order of metal ions obtained from breakthrough capacity and overall capacity at pH 2 was Cr(VI)>Sn(II)>Fe(III)>Cu(II)>Cd(II)${\simeq}Pb(II){\simeq}Cr(III){\simeq}Mn(II){\simeq}Ni(II){\simeq}Al(III)$. Desorption characteristics for Cr(VI) ion was investigated with desorption agents such as $HNO_3$, HCl, and $H_2SO_4$. It was found that the ion showed high desorption efficiency with 3 M HCl. As the result, the chelating resin, XAD-16-CTA was successfully applied to separation and preconcentration of Cr (VI) ion from several metal ions in metal finishing works.

• Journal of Welding and Joining
• /
• v.20 no.6
• /
• pp.746-747
• /
• 2002