• Journal of Soil and Groundwater Environment
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• v.18 no.1
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• pp.26-35
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• 2013

Outbreak of animal infectious diseases such as foot-and-mouth disease, avian influenza are becoming prevalent worldwide. For prevent the further infection, tremendous numbers of the infected or culled stocks are buried around farm. This burial method can generate a wide range of detrimental components such as leachate, nutrient, salt, and pathogenic bacteria, consequently. In this study, for the stabilization of livestock carcasses leachate, advanced oxidation processes utilizing the Fenton reaction was investigated in lab-scale experiments for the treatment for $COD_{Cr}$ of livestock carcass leachate. $COD_{Cr}$ reduction by the Fenton oxidation was investigated response surface methodology using the Box-Begnken methods were applied to the experimental results. A central composite design was used to investigate the effects of the independent variables of pH ($x_1$), dosage of $FeCl_2{\cdot}4H_2O$ ($x_2$) and dosage of $H_2O_2$ ($x_3$) on the dependent variables $COD_{Cr}$ concentration ($y_1$). A 1 M NaOH and $H_2SO_4$ was using for pH control, $FeCl_2{\cdot}4H_2O$ was used as iron catalyst and NaOH was used for Fenton reaction. The optimal conditions for Fenton oxidation process were determined: pH, dosage of $FeCl_2{\cdot}4H_2O$ and dosage of $H_2O_2$ were 3, 0.6 g (0.0151 M) and 7 mL(0.259 M), respectively. Statistical results showed the order of significance of the independent variables to be pH > initial concentration of ferrous ion > initial concentration of hydrogen peroxide.

• Composites Research
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• v.32 no.6
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• pp.355-359
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• 2019

The high efficient water splitting system should involve the reduction of high overpotential value, which was enhanced by the electrocatalytic reaction efficiency of catalysts, during the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) reaction, respectively. Among them, transition metal-based compounds (oxides, sulfides, phosphides, and nitrides) are attracting attention as catalyst materials to replace noble metals that are currently commercially available. Herein, we synthesized optimal monodisperse Co₃[Co(CN)₆]₂ PBAs by FESEM, and confirmed crystallinity by XRD and FT-IR, and thermal behavior of PBAs via TG-DTA. Also, we synthesized monodispersed Co₃O₄ nanocubes by calcination of Co₃[Co(CN)₆]₂ PBAs, confirmed the crystallinity by XRD, and proceeded OER measurement. Finally, the synthesized Co₃O₄ nanocubes showed a low overpotential of 312 mV at a current density of 10 mA·cm^-2 with a low Tafel plot (96.6 mV·dec^-1).

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.1
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• pp.26-34
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• 2010

The electrocatalystic prperties of Pt-Co and Pt-Ni with heteropolyacids (HPAs) entrapped in covalently cross-linked sulfonated poly(ether ether ketone) (CL-SPEEK)/HPA membranes were investigated for water electrolysis. The HP As, including molybdophosphoric acid (MoPA), and tungstophosphoric acid (TPA) were both used as membrane additives and electrocatalysts. The membrane electrode assembly (MEA) was prepared by a nonequilibrium impregnation-reduction (I-R) method. $Pt(NH_3)_4Cl_2$, $NiCl_2$ and $CoCl_2$ as electrocatalytic materials and $NaBH_4$ as reducing agent were used. I order to enhance electrocatalytic activity, the catalyst layer prepared above was electrodeposited (Dep) with HP A. Surface morphologies and physico-chemical properties of MEA were investigated by means of SEM, EDX and XRD. The electrocatalytic properties of composite membranes such as the cell voltage and coulombic charge in CV were in the order of magnitude: CL-SPEEK/MoPA40 (wt%) > CL-SPEEK/TPA30 > Nafion117. In the optimum cell applications for water electrolysis, the cell voltage of Pt/CL-SPEEK-MoPA40/Pt-Co (Dep-MoPA) and Pt/CL-SPEEK-TPA30/Pt-Co (Dep-TPA) was 1.75 Vat $80^{\circ}C$ and $1\;A/cm^2$ and voltage efficiency was 87.1%. Also, the observed activity of Pt-Co (84:16 atomic ratio by EDX) is a little higher than that of Pt-Ni (86: 14). The current density peak of electrodeposited electrodes were better a little than those of unactivated electrodes based on the same membranes.

• Korean Chemical Engineering Research
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• v.54 no.4
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• pp.574-581
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• 2016

In this study, CNT functionalized with pyrrolidine ring via 1,3-dipolar cycloaddition reaction with various amino acid and aldehyde was synthesized. Metallocene was subsequently immobilized on the functionalized CNT and CNT/polyethylene composite was prepared via in-situ ethylene polymerization. The polymerization activities of metallocene supported on CNT functionalized with glycine and benzaldehyde (Gly+BA-CNT) were similar to those of metallocene supported on CNT functionalized with N-benzyloxycarbonylglycine and paraformaldehyde (Z-Gly+PFA-CNT) although its Zr content was lower than that of Z-Gly+PFA-CNT. In the case of metallocene supported on Z-Gly+PFA-CNT, the even distribution of active sites hindered the diffusion of ethylene monomer and cocatalyst MAO due to steric hindrance during ethylene polymerization. Compared to polyethylene produced from homogeneous metallocene catalysts, CNT/PE composites had a higher initial degradation temperature ($T_{onset}$) and maximum mass loss temperature ($T_{max}$). It suggests that pyrrolidine functionalized CNT is uniformly dispersed and strongly interacted with the PE matrix, enhancing the thermal stability of PE.

• Membrane Journal
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• v.32 no.6
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• pp.411-426
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• 2022

Energy plays a significant role in modern lifestyle because of our extensive reliance over energy-operating devices. Therefore, there is a need for alternative and green energy resources that can fulfill the energy demand. For this, fuel cell (FCs) especially anion exchange membrane fuel cells (AEMFCs) have gained tremendous attention over the other (FCs) due to their fast reaction kinetics without using noble catalyst and allow to use of cheaper polymers with high performance. But lack of highly conductive, chemically, and mechanically stable anion exchange membrane (AEM) still main obstacle to the development of high performance AEMFCs. Therefore, graphene-based polymer composite membranes came into the existence as AEMs for the FCs. The exceptional properties of the graphene help to improve the performance of AEMs. Still, there are lot of challenges in the graphene derivatives based AEMs because of their high tendency of agglomeration in polymer matrix which reduced their potential. To overcome this issue surface modification of graphene derivatives is necessary to restrict their agglomeration and conserved their potential features that can help to improve the performance of AEM. Therefore, this review focus on the surface modification of graphene derivatives and their role in the fabrication of AEMs for the FCs.

• Journal of the Korean GEO-environmental Society
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• v.15 no.1
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• pp.63-68
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• 2014

In this study, it was found that determined the photocatalytic degradation of antibiotics (lincomycin, LM) with various catalyst composite of titanium dioxide ($TiO_2$), hydroxyapatite (HAP) and germanium (Ge) under UV-A irradiation. At first, various type of complex catalysts were investigated to compare the enhanced photocatalytic potential. It was observed that in order to obtain the removal efficiencies were $TiO_2/HAP/Ge$ > $TiO_2/Ge$ > $TiO_2/HAP$. The composition of $TiO_2/HAP/Ge$ using a statistical approach based on mixture analysis design, one of response surface method was investigated. The independent variables of $TiO_2$ ($X_1$), HAP ($X_2$) and Ge ($X_3$) which consisted of 6 condition in each variables was set up to determine the effects on LM ($Y_1$) and TOC ($Y_2$) degradation. Regression analysis on analysis of variance (ANOVA) showed significant p-value (p < 0.05) and high coefficients for determination value ($R^2$ of $Y_1=99.28%$ and $R^2$ of $Y_2=98.91%$). Contour plot and response curve showed that the effects of $TiO_2/HAP/Ge$ composition for LM degradation under UV-A irradiation. And the estimated optimal composition for TOC removal ($Y_2$) were $X_1=0.6913$, $X_2=0.2313$ and $X_3=0.0756$ by coded value. By comparison with actual applications, the experimental results were found to be in good agreement with the model's predictions, with mean results for LM and TOC removal of 99.2% and 49.3%, respectively.