• Journal of the Mineralogical Society of Korea
• /
• v.28 no.2
• /
• pp.173-185
• /
• 2015

Janggun mine (longitude $129^{\circ}$ 03'38.91" Latitude $36^{\circ}$ 51'31.59") had been operated as an underground mine for last few decades. As the part of the remediation process, the surface of tailing dump was covered with uncontaminated soil about 20 cm in depth and acacia trees were planted. Heavy metal uptake of acacia from tailing soil has continued for the past 15 years. Heavy metal concentration ranges of tailing soil that contaminated with As (66.43-9325.34 mg/kg), Cd (0.96-1.09 mg/kg), Cu (16.90-57.60 mg/kg), Pb (57.33-945.67 mg/kg), and Zn (154.48-278.61 mg/kg) have higher than those of control soil As (38.98 mg/kg), Cd (0.42 mg/kg), Cu (10.26 mg/kg), Pb (8.21 mg/kg), Zn (46.74 mg/kg). The As, Cd, Cu, Pb and Zn concentrations of leaf of acacia in highly contaminated tailing dump were 165.95, 0.04, 10.68, 3.18, 48.11 mg/kg, respectively. The metal contents of leaf of acacia tree that obtained from uncontaminated control soil are 1.31 of As, 3.90 of Cu, 0.22 of Pb and 11.01 mg/kg of Zn. It was investigated that in the acacia tree, heavy metals such as As, Cu, Pb and Zn tend to be more highly concentrated in bark and leaf, compared with sapwood and heartwood.

• Journal of the Korean Chemical Society
• /
• v.35 no.6
• /
• pp.645-652
• /
• 1991

The stability constants$(K_f)$ of the complexes of some transition and post-transition metal ions (Co(Ⅱ), Ni(Ⅱ), Cu(Ⅱ), Zn(Ⅱ), Cd(Ⅱ), Pb(Ⅱ), Hg(Ⅱ)) with $N_2O_3$-donor macrocyclic ligand, 1,15-diaza-3,4 : 12,13-dibenzo-5,8,11-trioxacyclooctadecane ($NtnOdienH_4$), have been determined by potentiometry in aqueous solution at $25^{\circ}C$. Log $K_f$ values of the complexes were : Co(Ⅱ): 3.83, Ni(Ⅱ) : 4.56, Cu(Ⅱ) : 7.74, Zn(Ⅱ) : 4.98, Cd(Ⅱ) : 3.91, Pb(Ⅱ) : 6.65, and Hg(Ⅱ) : 14.87. The order of stabilities of transition metal complexes was the same as the natural order of stability proposed by Williams-Irving. In post-transition metal complexes, the order of stabilities was Cd(Ⅱ) < Pb(Ⅱ) < Hg(Ⅱ), and the covalent character in metal ion-donor atoms bonds appeared a dominant factor in the stability. In methanol solution, each metal ion forms 1 : 1 complex, while Ni(Ⅱ) ion forms both 1 : 1 and 1 : 2 complexes. It was confirmed by $^1H-$ and $^{13}C-$NMR spectral study that the nitrogen atoms in the ligand were major contributors for the complexation of post-transition metal ions with the ligand. It was shown, by elementry analysis, electrical conductivity and magnetic susceptibility measurements, and spectral analysis, that solid Cu(Ⅱ)-and Zn(Ⅱ)-complexes have a distorted octahedral and a tetrahedral structure, respectively.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.4 no.2
• /
• pp.55-62
• /
• 1996

The purpose of this study is the evaluation of adsorption capacity of casts for heavy metals comparing with the activated carbon. The casts was obtained from vermicomposting of the mixed organic sludges which were generated from the treatment facilities for leather wastewater and cattle wastewater. The physico-chemical characteristics of cast was investigated. Also, the batch adsorption experiments of cast and activated carbon for heavy metals were carried out, and the results were analyzed by Freundlich isotherm. The buffering capacity to the acidic wastewater was founded in the cast, and the cation exchange capacity of cast impling adsorption capacity for soluble substances was evaluated as about 55me/100g. Those were implied that the cast have a large potential as a good adsorbent for soluble pollutants in wastewater. From the results of batch experiments, the removal efficiencies of tested various heavy metals including Pb, Cu, Cd, and Cr were very high value as 89-98% for the activated car-bon, and 80~95% for the casts except for Zn. The adsorption equilibriums for the two materials were achieved within 90 minutes. The order of preferable metals in the adsorption was found to be Pb>Cu>Cd>Cr>Zn on the cast and to be Pb>Cd>Cu>Cr>Zn on the activated carbon, respectively. From the above results, it might be con-cluded that cast is effectively available as a good adsorbent to treating the heavy metal bearing wastewater.

• Journal of Chitin and Chitosan
• /
• v.23 no.4
• /
• pp.234-243
• /
• 2018

In this study, the physicochemical properties of freeze dried (FD) and spray dried powders (SD-MD10, SD-MD20, SD-CD10, SD-CD20) from green coffee bean extract were investigated. Yields were 91.46% for FD powder and 71.63~87.98% for SD powders, respectively. The moisture content of SD powders (1.39~1.86%) was lower than that of FD powder (3.19%). L, a and b value of SD powders were higher than of FD powder. The particle size of the FD powder ($147.67{\mu}m$) was higher than that of the SD powders ($54.23{\sim}66.07{\mu}m$). The water absorption index of the SD powders (0.51-0.59) were lower than that of the FD powder (0.72). The water solubility index of the SD powders, 77.26-90.07%, was higher than that of the FD powder (70.07%). The total phenolic and flavonoid contents of SD-CD10 were 20.67 g/100 g and 8.92 g/100 g, respectively. The chlorogenic acid content of SD-CD10 (12.04 g/100 g) was higher than other SD powders. The DPPH and superoxide radical scavenging activities of SD-CD10 at $1,000{\mu}g/mL$ were 88.02% and 86.89%, respectively. The SD-CD10 was better than other SD powders on protective effects against oxidative stress in L-132 cells (87.33%). In conclusion, we provided experimental evidence that spray-dried powder of green coffee bean extracts have potential as functional food materials.

• Journal of the Korean Society of Mineral and Energy Resources Engineers
• /
• v.55 no.6
• /
• pp.588-595
• /
• 2018

This study has focused on evaluation of heavy metal contamination in seepage from 23 mine waste dumping sites in Korea. Seepage samples from the sites were taken and analyzed for heavy metals. The maximum levels (mg/L) in the samples were Al 53.98, As 16.19, Cd 1.15 Cu 37.30, Fe 28.64, Mn 39.00, Ni 0.097, Pb 0.750, and Zn 80.18. Among the sites, six mines were selected as continuous monitoring sites. As results of three months' monitoring of the sites, over the water guidelines for As, Cd, Cu, Fe, Mn, Zn and Al in seepage samples were found at two abandoned Au-Ag mines, Cd, Mn, Zn and Al at two Pb-Zn mines, and As, Fe and Mn at two other Fe-W mines. Therefore, those six mines need continuous monitoring on contamination assessment of seepage due to mining activities.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.16 no.4
• /
• pp.187-192
• /
• 2023

This paper deposited CdTe thin films on ITO glass substrates using sputtering equipment while changing RF power. As a result of measuring the thickness of the thin film, 1481Å at 100W, 2985Å at 150W, and 4684Å at 200W. And the mobility was measured as 8.43 cm2/Vs for 100W, 7.91 cm2/Vs for 150W, and 6.57 cm2/Vs for 200W. It can be seen that the thickness and mobility of the thin film are inversely proportional. As a result of confirming the transmittance, the transmittance was 84% at 905nm for 100W, the transmittance was 71% at 825nm for 150W, and 77% at 874nm for 200W. At 100 W, the thickness of the thin film was thin, so the transmittance was measured to be high. In other words, the correlation between transmittance and thickness can be seen. As a result of measuring the FHWM and particle size by changing the RF Power, 100W was calculated as 0.18, 150W was calculated as 0.19, and 200W was calculated as 0.73. The size of the particles was formed at 8.47Å at 100W, 7.98Å at 150W, and 8.7Å, which is the largest at 200W. In conclusion, it was found that the FHWM and particle size were inversely proportional.

• Journal of Environmental Science International
• /
• v.12 no.6
• /
• pp.627-633
• /
• 2003

The PM$_{10}$ concentration and chemical composition in an western area of Busan were surveyed between March, 2001 and February, 2002. The mean concentration was 98.2 $\mu\textrm{g}$/㎥ with a range of 18.1 to 330.6 $\mu\textrm{g}$/㎥. The magnitude of metallic elements in PM$_{10}$ is as follows in decreasing order: K>Ca>Na>Al>Fe. The mean values of crustal enrichment factors for four elements (Cd, Ni, Pb and Zn) were all higher than 10, which presumably resulted from the effect of anthropogenic origin. Moreover, the wintertime values were higher than springtime and summertime values, possibly due to emissions westerly transported from industries around this area. The contribution of soil particle to airborne particle in the study area was estimated to be 9.5%.

• Bulletin of the Korean Chemical Society
• /
• v.25 no.7
• /
• pp.969-976
• /
• 2004

Cassava peelings waste, which is both a waste and pollutant, was chemically modified using mercaptoacetic acid (MAA) and used to adsorb $Cu^{2+}\;and\;Cd^{2+}$ from aqueous solution over a wide range of reaction conditions at $30^{\circ}C$. Acid modification produced a larger surface area, which significantly enhanced the metal ion binding capacity of the biomass. An adsorption model based on the $Cu^{2+}/Cd^{2+}$ adsorption differences was developed to predict the competition of the two metal ions towards binding sites for a mixed metal ion system. The phytosorption process was examined in terms of Langmuir, Freundlich and Dubinin-Radushkevich models. The models indicate that the cassava waste biomass had a greater phytosorption capacity, higher affinity and greater sorption intensity for $Cu^{2+}\;than\;Cd^{2+}$. According to the evaluation using Langmuir equation, the monolayer binding capacity obtained was 127.3 mg/g $Cu^{2+}$ and 119.6 mg/g $Cd^{2+}$. The kinetic studies showed that the phytosorption rates could be described better by a pseudo-second order process and the rate coefficients was determined to be $2.04{\times}10^{-3}\;min^{-1}\;and\;1.98{\times}10^{-3}\;min^{-1}\;for\;Cu^{2+}\;and\;Cd^{2+}$ respectively. The results from these studies indicated that acid treated cassava waste biomass could be an efficient sorbent for the removal of toxic and valuable metals from industrial effluents.

• Mycobiology
• /
• v.45 no.2
• /
• pp.73-83
• /
• 2017

The ability of dead cells of endophytic Drechslera hawaiiensis of Morus alba L. grown in heavy metals habitats for bioremoval of cadmium ($Cd^{2+}$), copper ($Cu^{2+}$), and lead ($Pb^{2+}$) in aqueous solution was evaluated under different conditions. Whereas the highest extent of $Cd^{2+}$ and $Cu^{2+}$ removal and uptake occurred at pH 8 as well as $Pb^{2+}$ occurred at neutral pH (6-7) after equilibrium time 10 min. Initial concentration 30 mg/L of $Cd^{+2}$ for 10 min contact time and 50 to 90 mg/L of $Pb^{2+}$ and $Cu^{2+}$ supported the highest biosorption after optimal contact time of 30 min achieved with biomass dose equal to 5 mg of dried died biomass of D. hawaiiensis. The maximum removal of $Cd^{2+}$, $Cu^{2+}$, and $Pb^{2+}$ equal to 100%, 100%, and 99.6% with uptake capacity estimated to be 0.28, 2.33, and 9.63 mg/g from real industrial wastewater, respectively were achieved within 3 hr contact time at pH 7.0, 7.0, and 6.0, respectively by using the dead biomass of D. hawaiiensis compared to 94.7%, 98%, and 99.26% removal with uptake equal to 0.264, 2.3, and 9.58 mg/g of $Cd^{2+}$, $Cu^{2+}$, and $Pb^{2+}$, respectively with the living cells of the strain under the same conditions. The biosorbent was analyzed by Fourier Transformer Infrared Spectroscopy (FT-IR) analysis to identify the various functional groups contributing in the sorption process. From FT-IR spectra analysis, hydroxyl and amides were the major functional groups contributed in biosorption process. It was concluded that endophytic D. hawaiiensis biomass can be used potentially as biosorbent for removing $Cd^{2+}$, $Cu^{2+}$, and $Pb^{2+}$ in aqueous solutions.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.50 no.1
• /
• pp.85-92
• /
• 2008

This study was carried out to estimate heavy metal loads at plain area of the rural watersheds during farming season in 2006. The experimental area was belonging to Geum River watershed. That was located at the center of South Korea. Water samples were corrected at two kinds of aspects. One is regular sampling(every two month) and the other is irregular sampling(every rainfall event). The result showed that heavy metal properties of regular samples were highest at May and June with lively agricultural activities. Heavy metal concentration of irregular samples was lower than that of regular samples. But the heavy metal loads of irregular samples were high. The correlation between each heavy metals of regular samples was following as Mn-Cd > Mn-Fe > Mn-Al > Fe-Al > Al-Cd. The correlation of irregular samples was following as Fe-AI > Zn-Mn > Fe-Cd > Cd-Al. Loading rates of daily discharge the plain area of designed rural watershed during farming season were Al 3.070 kg/day, Cu 0.526 kg/day, Fe 0.745 kg/day, Zn 0.314 kg/day, Cd 0.010 kg/day, Cr 0.055 kg/day, Mn 0.140 kg/day and Pb 0.098 kg/day. Loading rate of discharge with heavy metals during the survey period was Al(577.23 kg) > Fe(140.08 kg) > Cu(98.93 kg) > Zn(58.99 kg) > Mn(26.34 kg) > Pb(18.51 kg) > Cr(10.34 kg) > Cd(1.93 kg).