• Title/Summary/Keyword: $pCO_2$

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Effect of pH Adjustment by CO2 on Coagulation and Aluminum Elution in Water Treatment (CO2 주입에 의한 pH 조정이 정수장 응집효율 및 알루미늄 용출에 미치는 영향)

  • Lee, Gil-Seong;Kim, Min-Chai;Kwon, Jae-Kook;Seo, Gyu-Tae
    • Journal of Korean Society of Environmental Engineers
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    • v.35 no.1
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    • pp.17-22
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    • 2013
  • In this study, a pH control method by carbon dioxide ($CO_2$) was applied to coagulation process in water treatment plant (WTP) to investigate the coagulation efficiency and residual dissolved aluminum when high pH raw water is flowing into the plant during algal blooming. Existing coagulant dose (1 mg/L in raw water) resulted in the pH reduction of 0.0384 by LAS, 0.0254 by PAC, 0.0201 by A-PAC, and 0.0135 by PACS2, respectively. And then the concentration of dissolved aluminum was 0.02 mg/L at pH 7.44, 0.07 mg/L at pH 7.96, 0.12 mg/L at pH 8.16, 0.39 mg/L at pH 8.38 showing the concentration increase with pH in the coagulation process. It was noteworthy that rapid increase was observed at pH above 8.0 next the rapid mixing. Therefore it is necessarily required to control pH below 7.8 in the coagulation process in order to meet drinking water quality standard of aluminum for high pH raw water into WTP, $CO_2$ injection could control pH successfully at about 7.3 even for the raw water of high pH above 8.0. In addition it was found that the pH control by $CO_2$ injection was significantly effective for coagulation in terms of turbidity removal, coagulant dosage, and residual dissolved aluminum concentration.

P123-Templated Co3O4/Al2O3 Mesoporous Mixed Oxides for Epoxidation of Styrene

  • Jung, Mie-Won;Kim, Young-Sil
    • Korean Journal of Materials Research
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    • v.22 no.6
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    • pp.316-320
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    • 2012
  • $Co_3O_4$, $Al_2O_3$ and $Co_3O_4$/$Al_2O_3$ mesoporous powders were prepared by a sol-gel method with starting matierals of aluminum isopropoxide and cobalt (II) nitrate. A P123 template is employed as an active organic additive for improving the specific surface area of the mixed oxide by forming surfactant micelles. A transition metal cobalt oxide supported on alumina with and without P123 was tested to find the most active and selective conditions as a heterogeneous catalyst in the reaction of styrene epoxidation. A bBlock copolymer-P123 template was added to the staring materials to control physical and chemical properties. The properties of $Co_3O_4$/$Al_2O_3$ powder with and without P123 were characterized using an X-ray diffractometer (XRD), a Field-Emission Scanning Electron Microscope (FE-SEM), a Bruner-Emmertt-Teller (BET) surface analyzer, and $^{27}Al$ MAS NMR spectroscopy. Powders with and without P123 were compared in catalytic tests. The catalytic activity and selectivity were monitored by GC/MS, $^1H$, and $^{13}C$-NMR spectroscopy. The performance for the reaction of epoxidation of styrene was observed to be in the following order: [$Co_3O_4$/$Al_2O_3$ with P123-1173 K > $Co_3O_4$/$Al_2O_3$ with P123-973 K > $Co_3O_4$-973 K>$Co_3O_4$/$Al_2O_3$-973 K > $Co_3O_4$/$Al_2O_3$ with P123-1473 K > $Al_2O_3$-973 K]. The existence of ${\gamma}$-alumina and the nature of the surface morphology are related to catalytic activity.

Synthesis of Co Diffused Cu Matrix by Electroplating and Annealing for Application of Mössbauer Source (뫼스바우어선원적용을 위한 전기도금과 열처리기법을 이용한 Co가 확산된 Cu기지체 제조)

  • Choi, Sang Moo;Uhm, Young Rang
    • Journal of the Korean Magnetics Society
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    • v.24 no.6
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    • pp.186-190
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    • 2014
  • To establish the coating conditions for $^{57}Co$, non-radioactive Co ions are dissolved in an acid solution and electroplated on to a copper plate. Then, the thermal diffusion of electroplated Co into a copper matrix was studied to apply a $^{57}Co$ $M{\ddot{o}}ssbauer$ source. Nanocrystalline Co particles were coated on a Cu substrate using DC electro-deposition at a pH of 1.89 to 5 and $20{\sim}30mA/cm^2$. The average grain size was up to 54 nm as the pH increased to 5. The second phase of Co-oxide was formatted as the pH was increased above 4. The diffusion degree was evaluated by mapping using scanning electron microscopy (SEM). The influence of different annealing conditions was investigated. The diffusion depth of Co depends on the annealing temperature and time. The results obtained confirm that the deposited Co diffused almost completely into a copper matrix without substantial loss at an annealing temperature of $900^{\circ}C$ for 2 hours.

Effects of Operating Variables on Sorption Capacity of CO2 Absorbents for SEWGS Process (SEWGS 공정용 CO2 흡수제들의 흡수능력에 미치는 조업변수들의 영향)

  • Ryu, Ho-Jung;Kim, Hyo-Sung;Lee, Seung-Yong;Lee, Dong-Ho;Kim, Jae-Chang
    • Korean Chemical Engineering Research
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    • v.50 no.6
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    • pp.994-1001
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    • 2012
  • The Effects of operating variables on reactivity of two $CO_2$ absorbents (PKM1-SU and P4-600) for SEWGS process were investigated in a pressurized fluidized bed reactor. For both $CO_2$ absorbents, $CO_2$ sorption capacity decreased as the number of absorption-regeneration cycles increased. PKM1-SU absorbent represented higher $CO_2$ sorption capacity than that of P4-600 absorbent. However, P4-600 absorbent represented better performance than PKM1-SU absorbent from the view points of regeneration temperature and regeneration rate. For PKM1-SU absorbent, $CO_2$ sorption capacity increased as the steam concentration increased. However, $CO_2$ sorption capacity increased initially as the steam concentration increased from 5% to 10%, but maintained thereafter for P4-600 absorbent. For both $CO_2$ absorbents, $CO_2$ sorption capacity increased as the final regeneration temperature increased. For PKM1-SU absorbent, $CO_2$ sorption capacity increased as the pressure increased and the increment tendency was drastic at higher pressure than 15 bar.

Evaluation of buccal mucoadhesive [P(AA-co-PEGMM)] copolymer films containing butorphanol tartrate (Butolphanol tartrate 함유 구강점막 점착성 [P(AA-co-PEGMM)] 공중합체 필름의 평가)

  • Kim, Joun-Sik;Han, Kun
    • Journal of Pharmaceutical Investigation
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    • v.32 no.1
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    • pp.1-6
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    • 2002
  • The mucoadhesive characteristics of [P(AA-co-PEGMM)] films by estimating the glass transition temperature $(T_g)$, analyzing surface energy and studying FT-IR was previously reported. In this study, the possibility of buccal mucoadhesive dosage form of [P(AA-co-PEGMM)] films by mucoadhesive force measurements and dissolution tests were also investigated. Mucoadhesiveness of [P(AA-co-PEGMM)] films was compared with cr-PAA and cr-PEGMM films crosslinked with 3% ethyleneglycol dimethacrylate (EGDMA). The buccal mucoadhesive force of [P(AA-co-PEGMM)] films increased with increasing content of PEGMM. [P{AA-co-PEGMM (18 mole%)}] films showed a significantly greater mucoadhesiveness than cr-PAA and cr-PEGMM films. The mucoadhesive force measured in normal saline (pH 5.0) was higher than that measured in phosphate buffer (pH 6.8) because of the pH dependence of hydrogels with carboxyl ions within the PAA. Moreover, the mucoadhesive force of [P{AA-co-PEGMM (18 mole%)}] films was at maximum after 2 hr attachment of buccal mocosa and it was maintained over $1\;N/cm^2$ for up to 10 hr. In dissolution studies, the release of butorphanol tartrate from [P(AA-co-PEGMM)] films increased with increasing PEGMM content, and films prepared with 18 mole% PEGMM gave almost zero order release kinetics.

Synthesis, Characterization, and Catalytic Properties of Gp 6 Metal Complexes of 1-N,N-dimethylaminomethyl-$1^{\prime}$,2-bis(diphenylphosphino)ferrocene (FcNPP). X-ray Crystal Structure of W$(CO)_4({\eta}^2-FcNPP(O)-P,N)$

  • Kim, Tae-Jeong;Kim, Yong-Hoon;Kim, Eun-Jin;Oh, Sang-Ho;Kim, Hong-Seok;Jeong, Jong-Hwa
    • Bulletin of the Korean Chemical Society
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    • v.15 no.5
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    • pp.379-386
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    • 1994
  • Reactions of 1',2-bis(diphenylphosphino)-l-(N,N-dimethylaminomethyl)ferrocene (FcNPP) with $M(CO)_6$ (M=Cr, Mo, W) in the presence of TMNO (Trimethylamine oxide) in a stoichiometric ratio of 1 : 1.5 : 3.5 produced a series of Gp 6 metal carbonyl derivatives with a variety of coordination modes: M(CO)$_4({\eta}^2$-FcNPP-P,P) (M=Cr, Mo, W), $M(CO)_5({\eta}^1-FcNPP-P) (M=Mo, W)\;,\; M_2(CO)_9({\eta}^1\;,\;{\eta}^2-FcNPP-P,P,N) (M=Cr, Mo)\;,\;M_2(CO)_{10}({\eta}^1\;,\;{\eta}^1-FcNPP-P,P) (M=Cr, Mo, W)\;, and\;W(CO)_4({\eta}^2-FcNPP(O)-P,N)$. All these complexes were characterized by microanalytical and spectroscopic techniques. In one case, the structure of W(CO)$_4({\eta}^2$-FcNPP(O)-P,N) was determined by X-ray crystallography. Crystals are monocinic, space group P$2_{1/C}$, with a=10.147(2), b=19.902(3), c=19.821(4) ${\AA},\;{\beta}=96.88(2)^{\circ},\;V=3974(l){\AA}^3$, Z=4, and $D_{calc}=1.64 g cm^{-3}$. The geometry around the central tungsten metal is a distorted octahedron, with the nitrogen and phosphorus atoms being cis to each other. Some of these complexes exhibited catalytic activities in the allylic oxidation and epoxidation of cholesterly acetate. Other oxidation products were also formed with the different chemical yields and product distribution depending upon the ligand and the central metal.

Variations in electrode characteristics through simplification of phosphorus-doped NiCo2O4 electrode manufacturing process (인이 도핑된 NiCo2O4 전극 제조 공정의 간소화를 통한 전극 특성의 변화)

  • Seokhee-Lee;Hyunjin Cha;Jeonghwan Park;Young Guk Son;Donghyun Hwang
    • Journal of the Korean institute of surface engineering
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    • v.56 no.5
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    • pp.299-308
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    • 2023
  • In this study, phosphorus (P)-doped nickel cobaltite (P-NiCo2O4) and nickel-cobalt layered double hydroxide (P-NiCo-LDH) were synthesized on nickel (Ni) foam as a conductive support using hydrothermal synthesis. The thermal properties, crystal structure, microscopic surface morphology, chemical distribution, electronic state of the constituent elements on the sample surface, and electrical properties of the synthesized P-NiCo2O4 and P-NiCo-LDH samples were analyzed using thermogravimetric analysis-differential scanning calorimetry (TGA-DSC), X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). The P-NiCo2O4 electrode exhibited a specific capacitance of 1,129 Fg-1 at a current density of 1 Ag-1, while the P-NiCo-LDH electrode displayed a specific capacitance of 1,012 Fg-1 at a current density of 1 Ag-1. When assessing capacity changes for 3,000 cycles, the P-NiCo2O4 electrode exhibited a capacity retention rate of 54%, whereas the P-NiCo-LDH electrode showed a capacity retention rate of 57%.

Phosphorus Accumulation and Utilization Efficiency in Soybean Plant under Atmospheric CO2 Enrichment

  • Sa, Tongmin;Kim, Jong-Soo
    • Journal of Applied Biological Chemistry
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    • v.44 no.1
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    • pp.16-19
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    • 2001
  • Soybean plants(Glycine max [L.] merr.) inoculated with Bradyrhizobium japonicum MN110 were grown in growth chambers under 400 or $800{\mu}l{\cdot}l^{-1}$ atmospheric $CO_2$ and harvested at 25, 28, 32, and 35 DAT to examine the effect of $CO_2$ enrichment on phosphorus accumulation, uptake, and utilization efficiency during vegetative growth. Phosphorus concentration in leaf was lower in high $CO_2$ plant by 47% at 25 DAT and 34% at 35 DAT than those in the control plant but phosphorus concentrations in stem, root and nodule were not affected by $CO_2$ enrichment. Total phosphorus accumulation increased 3.9-fold in high $CO_2$ plant and 3.2-fold in the control plant between 25 and 35 DAT. Elevated $CO_2$ caused a decrease in the whole plant phosphorus concentration by 35%, which was due almost entirely to a decrease in the phosphorus concentration of leaves. $CO_2$ enrichment increased phosphorus utilization efficiency in the whole plant by 70% during the experimental period. Plants exposed to high $CO_2$ had larger root systems than under ambient $CO_2$, but high $CO_2$ plants had lower P-uptake efficiency. Averaged over four harvests, plants at high $CO_2$ had 38% larger root mass that was more than offset the 20% lower efficiency of P-uptake and accounted for increased phosphorus accumulation by high $CO_2$ plant. These results suggest that the reduced phosphorus concentration in soybean plant under $CO_2$ enrichment may be an acclimation response to high $CO_2$ concentration or enhanced starch accumulation, resulting in the plants to have a lower phosphorus requirement on a unit dry weight basis or a high phosphorus utilization efficiency under these conditions.

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Quantitative analysis of Spirulina platensis growth with CO2 mixed aeration

  • Kim, Yong Sang;Lee, Sang-Hun
    • Environmental Engineering Research
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    • v.23 no.2
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    • pp.216-222
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    • 2018
  • The growth characteristics of Spirulina platensis were investigated using four photo-bioreactors with $CO_2$-mixed air flows. Each reactor was operated under a specific condition: 3% $CO_2$ at 50 mL/min, 3% $CO_2$ at 150 mL/min, 6% $CO_2$ at 50 mL/min, and 6% CO2 at 150 mL/min. The 3% $CO_2$ at 150 mL/min condition produced the highest algal growth rate, while the 6% $CO_2$ at 150 mL/min conditioned produced the lowest. The algal growth performance was suitably assessed by the linear growth curve rather than the exponential growth. The medium pH decreased from 9.5 to 8.7-8.8 (3% $CO_2$) and 8.4-8.5 (6% $CO_2$), of which trends were predicted only by the pH-carbonate equilibrium and the reaction kinetics between dissolved $CO_2$ and $HCO_3{^-}$. Based on the stoichiometry between the nutrient amounts and cell elements, it was predicted that depleted nitrogen (N) at the early stage of the cultivation would reduce the algal growth rates due to nutrient starvation. In this study, use of the photobioreactors capable of good light energy distribution, proper ranges of $CO_2$ in bubbles and medium pH facilitated production of high amounts of algal biomass despite N limitation.

Neutralization of Alkaline Wastewater with CO2 in a Continuous Flow Jet Loop Reactor (연속흐름형 Jet loop reactor에서 CO2를 이용한 알칼리폐수의 중화)

  • Kang, Dae-Yeop;Kim, Mi-Ran;Lim, Jun-Heok;Lee, Tae-Yoon;Lee, Jea-Keun
    • Korean Chemical Engineering Research
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    • v.54 no.1
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    • pp.101-107
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    • 2016
  • This paper investigates the feasibility of applying the jet loop reactor for the neutralization of alkaline wastewater using carbon dioxide ($CO_2$). In this study, pH changes and $CO_2$ removal characteristics were examined by changing influent flow rate of alkaline wastewater (initial pH=10.1) and influent $CO_2$ flow rates. Influent flow rates of alkaline wastewater ($Q_{L,in}$) ranged between 0.9 and 6.6 L/min, and inlet gas flow rate ($Q_{G,in}$) of 1 and 6 L/min in a lab-scale continuous flow jet loop reactor. The outlet pH of wastewater was maintained at 7.2 when the ratio ($Q_{L,in}/Q_{G,in}$) of $Q_{L,in}$ and $Q_{G,in}$ was 1.1. However, the $CO_2$ removal efficiency and the outlet pH of wastewater were increased when $Q_{L,in}/Q_{G,in}$ ratio was higher than 1.1. Throughout the experiments, the maximum $CO_2$ removal efficiency and the outlet pH of wastewater were 98.06% and 8.43 at the condition when $Q_{G,in}$ and $Q_{L,in}$ were 2 L/min and 4 L/min, respectively.