• Applied Chemistry for Engineering
• /
• v.7 no.1
• /
• pp.83-90
• /
• 1996

The changing shape of absorption and fluorescence spectra will increasing S/D in AO-AOT system decreases and then increases again. The aggregation and disaggreation in AO-AOT system occurres. According to increasing temperature, the absorbance increases in pure AO system. But it gradually decreases in premicellar range(S/D = 10, 20, 50 and 80). The disappearance degree of metachromasy according to the concentration of added salt to AO-AOT system is increased. However, the case of $NaNO_3$is reversed. The order of disappearance degree of metachromasy on cationic salts is $Li^+$, $Na^+$ > $Mg^{2+}$ > $Ca^{2+}$, and the order of it on anionic salts is $Cl^-$ > $SO_4{^{2-}}$ > $NO_3{^-}$.

• Journal of Korean Society of Environmental Engineers
• /
• v.30 no.7
• /
• pp.712-720
• /
• 2008

Sediment and interstitial water samples from ten lagoons in the Northeastern coastal part of South Korea were analyzed to obtain the concentrations of metals and inorganic ligand. These data, coupled with pH and ionic strength, were used to compute the aqueous speciation of the metals in the interstitial water using the MINTEQA2 equilibrium program. The K and Na were almost entirely present as the free aqua ions, but Co, Cd, Ni, Pb and Zn were existed as various metal-ligand complexes. Metals such as Al, As, and Cr formed 3$\sim$4 metal-ligand complexes. In the interstitial water with high chloride concentrations, almost all of the metals were dominated by free aqua ions. Metals of Cd, Co, Ni, Pb and Zn were bound as chloride-metal complexes of the type M$^{x+}$ + xCl$^-$, and Fe, Mn and Mg were dominated by sulfate equilibria(M$^{2+}$ + SO$_4{^{2-}}$). Hg(II) was speciated as HgCl$_2$(aq), HgCl$_3{^-}$ and HgCl$_4{^-}$. However, in the interstitial water with low chloride concentrations, Hg(II) and Cd(II) were existed as chloride-metal complexes, metals of Cu, Mg, Mn, Ni, Pb and Zn were dominated by sulfate equilibria, and the speciation of Fe(II) was bound as Fe(OH)$_2{^+}$, Fe(OH)$_3$(aq). However, Al, As and Cr were dominated by hydroxy-metal and oxide-metal species in nearly all of the lagoons.

• Membrane Journal
• /
• v.27 no.5
• /
• pp.449-457
• /
• 2017

In this study, the 10 stages stacked module was designed by increasing the number of unit cells in the membrane capacitive deionization(MCDI) process. The aminated polysulfone and sulfonated poly(ether ether ketone) were synthesized and coated on porous carbon electrode by casting method. The salt removal efficiency was measured for the 10 stage stacked module under the operation conditions of adsorption voltage and time, desorption voltage and time, flow rate and concentration of feed water, and di-valent solutions including $CaSO_4$, $MgCl_2$ and tap water. Typically, when 100 mg/L of NaCl as the feed was used, the salt removal efficiency was 98.3% at a flow rate of 100 mL/min, the adsorption condition of 1.2 V/3 min and desorption condition of -0.5 V/5 min.

• Analytical Science and Technology
• /
• v.17 no.3
• /
• pp.217-224
• /
• 2004

A taste sensor system composed of mini electrode array was built in a flow cell. Potentiometric signals from 9 electrodes were collected for drinking waters and alcoholic beverages which were diluted in a low concentration buffer solution (0.005 M Tris-$H_2SO_4$ pH 7.2) for the measurement. The measured results were treated with the principal component analysis (PCA), and grouped on a two or three dimensional PCA coordinate to discriminate the tastes of each beverage. It is demonstrated that the taste sensor system of this work may be used for the quality control of beverages in production or the examination of their taste variation in the market.

• Journal of Korean Society of Environmental Engineers
• /
• v.30 no.3
• /
• pp.302-313
• /
• 2008

The purposes of this study are to investigate the concentration levels of fine particles, so called PM$_{2.5}$, to identify the affecting sources, and to estimate quantitatively the source contributions of PM$_{2.5}$. Ambient air sampling was seasonally carried out at two sites in Pohang(a residential and an industrial area) during the period of March to December 2003. PM$_{2.5}$ samples were collected by high volume air samplers with a PM$_{10}$ Inlet and an impactor for particle size segregation, and then determined by gravimetric method. The chemical species associated with PM$_{2.5}$ were analyzed by inductively coupled plasma spectrophotometery(ICP) and ion chromatography(IC). The results showed that the most significant season for PM$_{2.5}$ mass concentrations appeared to be spring, followed by winter, fall, and summer. The annual mean concentrations of PM$_{2.5}$ were 36.6 $\mu$g/m$^3$ in the industrial and 30.6 $\mu$g/m$^3$ in the residential area, respectively. The major components associated with PM$_{2.5}$ were the secondary aerosols such as nitrates and sulfates, which were respectively 4.2 and 8.6 $\mu$g/m$^3$ in the industrial area and 3.7 and 6.9 $\mu$g/m$^3$ in the residential area. The concentrations of chemical component in relation to natural emission sources such as Al, Ca, Mg, K were generally higher at both sampling sites than other sources. However, the concentrations of Fe, Mn, Cr in the industrial area were higher than those in the residential area. Based on the principal component analysis and stepwise multiple linear regression analysis for both areas, it was found that soil/road dust and secondary aerosols are the most significant factors affecting the variations of PM$_{2.5}$ in the ambient air of Pohang. The source apportionments of PM$_{2.5}$ were conducted by chemical mass balance(CMB) modeling. The contributions of PM$_{2.5}$ emission sources were estimated using the CMB8.0 receptor model, resulting that soil/road dust was the major contributor to PM$_{2.5}$, followed by secondary aerosols, vehicle emissions, marine aerosols, metallurgy industry. Finally, the application and its limitations of chemical mass balance modeling for PM$_{2.5}$ was discussed.

• Journal of Environmental Science International
• /
• v.25 no.5
• /
• pp.715-726
• /
• 2016

This study investigates the characteristics of metallic and ionic elements concentration, concentration according to transport path, and factor analysis in $PM_{10}$ at Guducsan in Busan in the springtime of 2015. $PM_{10}$ concentration in Guducsan and Gwaebeopdong were $59.5{\pm}9.04{\mu}g/m^3$ and $87.5{\pm}20.2{\mu}g/m^3$, respectively. Contribution rate of water-soluble ions and secondary ion in $PM_{10}$ concentration in Guducsan were 37.0% and 27.8% respectively. [$NO_3{^-}/SO{_4}^{2-}$] ratio and contribution rate of sea salt of $PM_{10}$ in Guducsan and Gwaebeopdong were 0.91 and 1.12, 7.0% and 5.3%, respectively. The results of the backward trajectory analysis indicates that $PM_{10}$ concentration, total inorganic water-soluble ions and total secondary ions were high when the air parcels moved from Sandong region in China than non-Sandong and northen China to Busan area. The results of the factor analysis at Guducsan indicates that factor 1 was anthropogenic source effects such as automobile emissions and industrial combustion processes, factor 2 was marine sources such as sea salts from sea, and factor 3 was soil component sources.

• Journal of the Korean Geosynthetics Society
• /
• v.19 no.2
• /
• pp.23-33
• /
• 2020

This study determines the basic properties and acid rock drainage generation capacity of Pohang tertiary mudstone through laboratory experiments. According to X-ray fluorescence (XRF) analysis results, the mudstone of this area mostly comprised of SiO₂ with a proportion of approximately 60%, followed in order by Al₂O₃ and Fe₂O₃. As such, it is clear that there is an abundance of aluminosilicates with a high probability of generating acid rock drainage. The XRD analysis showed that the mudstone contains pyrite (FeS₂), it is highly likely to generate acid rock drainage, and inductively coupled plasma atomic emission spectroscopy (ICP-AES) analysis results showed that the mudstone samples contained a high amount of Fe²⁺ ions. As a result of anion analysis measured by ion chromatography (IC), all mudstone samples were measured to have high SO^2-₄ concentrations. According to elemental analysis, the total sulfur (S) content was high, which in turn indicates a high risk of acid rock drainage generation reflected by a maximum potential acidity (MPA) higher than 1%. All in all, although there were slight deviations between the tertiary mudstone samples, overall, the samples exhibited high acid rock drainage generation capacities.

• Clean Technology
• /
• v.28 no.1
• /
• pp.38-45
• /
• 2022

CuCl₂-loaded V₂O₅-WO₃/TiO₂ catalyst showed excellent activity in the catalytic oxidation of elemental mercury to oxidized mercury even under SCR condition in the presence of NH₃, which is well known to significantly inhibit the oxidation activity of elemental mercury by HCl. Moreover, it was confirmed that, when SO₂ was present in the reaction gas together with HCl, excellent elemental mercury oxidation activity was maintained even though CuCl₂ supported on the catalyst surface was converted to CuSO₄. This is thought to be because not only HCl but also the SO₄ component generated on the catalyst surface promotes the oxidation of elemental mercury. However, in the presence of SO₂, the total mercury balance before and after the catalytic reaction was not matched, especially as the concentration of SO₂ increased. In order to understand the cause of this, further studies are needed to investigate the effect of SO₂ in the SnCl₂ aqueous solution employed for mercury species analysis and the effect of sulfate ions generated on elemental mercury oxidation. It was confirmed that SO₂ also promotes NO_x removal activity, which is thought to be because the increase in acid sites by SO₄ generated on the catalyst surface by SO₂ facilitates NH₃ adsorption. The composition change and structure of the components present on the catalyst surface under various reaction conditions were measured by XRD and XRF. These measurement results were presented as a rational explanation for the results that SO₂ enhances the oxidation activity of elemental mercury and the NO_x removal activity in this catalyst system.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.33 no.5
• /
• pp.448-454
• /
• 2000

This study was to examine the physicochemical characteristics of coagulation reaction between ignited oyster shell powder (IOSP) and red tide organisms (RTO), and its feasibility, in developing a technology for the removal of RTO bloom in coastal sea,IOSP was made from oyster shell and its physicochemical characteristics were examined for particle size distribution, surface characteristic by scanning electron microscope, zeta potential, and alkalinity and pH variations in sea water. Two kinds of RTO that were used in this study, Cylindrotheca closterium and Skeletonema costatum, were sampled in Masan bay and were cultured in laboratory. Coagulation experiments were conducted using various c(Incentrations of IOSP, RTO, and a jar tester. The supernatant and RTO culture solution were analyzed for pH, alkalinity, RTO cell number, IOSP showed positive zeta potentials of $11.1{\~}50.1\;mV\;at\;pH\;6.2{\~}12.7$, A positive zeta potential of IOSP slowly decreased with decreasing pNa 4,0 to 2,0. When pNa reached zero, the zeta potential approached zero, When a pMg value was decreased, the positive zeta potential of IOSP increased until pMg 3.0 and decreased below pMg 3.0. IOSP showed 4.8 mV of positive zeta potential while RTO showed -9.2 mV of negative zeta potential in sea water. A positive-negative EDL (electrical double-layer) interaction occurred between $Mg(OH)_2$ adsorption layer of IOSP and RTO in sea water so that EDL attractive force always worked between them. Hence, their coagulation reaction occurred at primary minimum on which an extreme attractive force acted because of charge neutralization by $Mg(OH)_2$ adsorption layer of IOSP. As a result, the coagulation reaction was rapidly processed and was irreversible according to DLVO (Deriaguin-Landau-Verwey-Overbeek) theory. Removal rates of RTO were exponentially increased with increasing both IOSP concentration and G-value. The removal rates were steeply increased until 50 mg/l of IOSP and reached $100{\%}\;at\;400\;mg/l$ of IOSP. Removal rates of RTO were $70.5,\;70.5,\;81.7,\;85.3{\%}$ for G-values of $1,\;6,\;29,\;139\;sec^(-1)$at IOSP 100 mg/l, respectively. This indicated that mixing (i.e., collision among particles) was very important for a coagulation reaction.

• Journal of Bio-Environment Control
• /
• v.14 no.3
• /
• pp.203-211
• /
• 2005

The experiment was conducted to investigate the nutrition absorption pattern in the growth stages and develope the optimal nutrient solution hydroponically grown the tomato in closed substrate culture system with the nutrient solution of National Horticultural Research Station in Japan into 1/2S, 1 S, and 2S. When plant was grown in 1/2 S, the growth and yield were high and the pH and EC in the rooting zone were stable. Suitable composition of nutrient solution for tomato was $NO_3-N$ 7.1, $PO_{4}$-P 2.1, K 4.0, Ca 3.1, Mg 1.2, and $SO_{4}-S\;1.2\;me{\cdot}L^{-1}$ in the early growth stage and $NO_3-N$ 6.5, $PO_4-P$ 2.3, K 3.4, Ca 3.1, Mg 1.1, and $SO_4-S\;1.1\;me{\cdot}L^{-1}$ in the late growth stage by calculating a rate of nutrient and water uptake. To estimate the suitability for the nutrient solution of tomato in a development of optimum nutrient solution of tomato developed by Wonkwang university in korea (WU), plant was grown in perlite substrate supplied with different solution and strengths(S) by research station for greenhouse vegetable and floricultuin in the Netherlands (Proefstation voor tuinbouw onder glas te Naaldwijk; PTG) of 1/2 S, 1 S and 2 S, respectively, The growth was good at the PTG and WU of 2 S in early growth stage, and at the WU 2S in late growth stage. The highest yield of tomato obtained in the WU of 2 S, although blossom-end rot was appeared in all treatments. pH and EC in root zone of WU of 2 S were stable during the early and late growth stage. Therefore when plant was grown in WU of 2 S, N and P content in the nutrient solution need to low, according N and P content of their leaves were high in WU of 2 S.