• Nano
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• v.13 no.10
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• pp.1850123.1-1850123.9
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• 2018

The cetyltrimethyl ammonium bromide (CTAB)-modified montmorillonite (MMT) was synthesized via a novel "dissolution and reassembly" method. To determine the optimal formula, the adsorption of C.I. Reactive Red 2 (X3B) with CTAB/MMT was investigated. The optimal CTAB/MMT nanocomposite was used to remove 2,6-dichlorophenol and p-nitrophenol from aqueous solutions. The adsorption results can be described by Langmuir isotherm, and the adsorption capacities were 200 mg/g and 125 mg/g for 2,6-dichlorophenol and p-nitrophenol, respectively. To realize the quick separation and recycle, the magnetic CTAB/MMT was further strategized and synthesized. The adsorption equilibrium time was 15 min for both contaminants; the ions' strength showed a little bit of influence on the adsorption performance. In addition, compared with acidic condition, neutral condition was more beneficial to the adsorption reaction. Due to the addition of $Fe_3O_4$, the adsorption capacities of this magnetic nanocomposite for 2,6-dichlorophenol and p-nitrophenol were a little bit decreased, which were 170 mg/g and 91 mg/g, respectively. However, the magnetic nanocomposite can be separated within 30 s under an external magnetic field, which would be useful in the practical application.

• Applied Chemistry for Engineering
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• v.32 no.1
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• pp.15-19
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• 2021

In this study, we studied a facile method for the synthesis of stable and nearly spherical gold nanoparticles using a tyrosine-rich peptide, Tyr-Tyr-Gly-Tyr-Tyr (YYGYY), as both the reducing and capping agent. The peptide coated spherical and polycrystalline gold nanoparticles with diameters from 3 to 15 nm were successfully synthesized by varying the concentration of the peptide and metal precursor under UV irradiation. The nanoparticles were then characterized by transmission electron microscopy (TEM), UV-Vis spectroscopy, scanning transmission electron microscopy-energy dispersive X-ray spectroscopy (STEM-EDS), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). Furthermore, the catalytic activity of gold nanoparticles was confirmed by the reduction of 4-nitrophenol to 4-aminophenol, in which the catalytic reaction rate constant was 7.3 × 10-3 s-1.

• YAKHAK HOEJI
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• v.40 no.4
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• pp.449-455
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• 1996

Betaine is one of the major water-soluble components in Lycii Fructus. In the present study the effect of repeated betaine treatment on the hepatotoxicity and the cytochrome P-4 50-dependent enzyme system was examined in adult female rats. Administrations of betaine (100 or 1,000mg/kg/day, ip) to rats repeatedly for 4 or 9 days did not evoke hepatotoxic response as determined by increases in glutamic pyruvic transaminase(GPT) and glutamic oxaloacetic transaminase(GOT) activities measured 24 hours following the final dose of betaine. The activities of aminopyrine N-demethylase, p-nitroanisole O-demethylase and p-nitrophenol hydroxylase as well as the contents of cytochrome P-450 were determined in hepatic microsomes of rats treated with betaine(1,000mg/kg/day, ip) for 4 or 9 days. Repeated treatment of rats with betaine for a period of 4 days induced a marginal decrease in the contents of cytochrome P-450, but did not influence the activities of p-nitrophenol hydroxylase, p-nitroanisole O-demethylase, or aminopyrine N-demethylase. Extension of the betaine treatment to 9 consecutive days failed to alter the parameters for hepatic drug metabolizing activity determined in the present study. Since repeated large doses of betaine were demonstrated to be tolerated by rats without showing any toxicity or changes in drug metabolizing enzyme activities in the liver, this compound appears to be relatively safe to animals upon long-term ingestion.

• Bulletin of the Korean Chemical Society
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• v.33 no.6
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• pp.2023-2027
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• 2012

An efficient and practical synthesis of MBH adducts of aryl vinyl ketones was developed using DABCO and 4-nitrophenol as a proton donor. Addition of a proton donor and the use of excess amounts (3.0 equiv) of aldehydes were highly beneficial for the yields of MBH adducts of aryl vinyl ketones.

• Journal of Environmental Health Sciences
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• v.30 no.3
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• pp.214-220
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• 2004

The microcosm type wetland systems were constructed in order to treat wastewater contaminated with parathion. The microcosm reactor consisted of marsh and pond type. The experiment was carried out using batch (marsh or pond) and continuous (marsh-pond and pond-marsh type) systems. In the batch reactor, marsh-type wetland completely removed parathion in water within 8 days, while pond reactor removed 97% of parathion during the same period. During parathion degradation, the amount of 4-nitrophenol production, one of the metabolites from parathion degradation, was higher in marsh-type batch reactor. In the continuous systems, both marsh-pond and pond-marsh combination systems effectively removed parathion from water, and the production of 4-nitrophenol was also minimal. In the extraction experiment, the parathion and its metabolite were not found in the wetland soil and the plant. In order to achieve both aerobic and anaerobic conditions, the continuous wetland system combining marsh and pond type can be the alternative for the non-point source pollutants such as parathion pesticide.

• Bulletin of the Korean Chemical Society
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• v.33 no.9
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• pp.3009-3016
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• 2012

This study evaluated the use of iron-impregnated SBA-15 (Fe/SBA-15) as a catalyst for the oxidative degradation of persistent phenol analogues, such as 2-chlorophenol (2-CP), 4-chlorophenol (4-CP), 2-nitrophenol (2-NP), 4-nitrophenol (4-NP) and 2,4,6-trichlorophenol (2,4,6-TCP) in water. The oxidation reactions were carried out with reaction time, concentration of the phenols, amount of the catalysts, reaction temperature, pH of the reaction mixture as the process variables with or without using hydrogen peroxide as the oxidizing agent. The conversion achieved with Fe/SBA-15 at 353 K for 2-CP, 4-CP, 2-NP, 4-NP, 2,4,6-TCP was 80.2, 71.2, 53.1, 62.8, 77.3% in 5h with a reactant to $H_2O_2$ mole ratio of 1:1, and 85.7, 65.8, 61.9, 63.7, 78.1% in the absence of $H_2O_2$, respectively. The reactions followed pseudo first order kinetics. The leachability study indicated that the catalyst released very little iron into water and therefore, the possibility of secondary pollution is negligible.

• Environmental Engineering Research
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• v.25 no.2
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• pp.186-196
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• 2020

Pillared clays with Zr and Fe/Cu/Zr polycations have been prepared from natural clays found in large deposits of Kazakhstan and assessed as catalysts for the catalytic wet peroxide oxidation (CWPO), using 4-nitrophenol (4-NP) as model compound. The performance of the catalysts was followed by measuring the concentration of 4-NP, H₂O₂ and the total organic carbon (TOC), considering C_4-NP = 5 g L^-1, $C_{H_2O_2}$ = 17.8 g L^-1, C_cat = 2.5 g L^-1, initial pH = 3.0 and T = 50℃. At those selected conditions, the pillared clays showed higher activity than natural clays in the CWPO of 4-NP. The conversion of the model pollutant was complete when Fe/Cu/Zr-PILCs were used, with the TOC removal reaching 78.4% after 24 h with the best Fe/Cu/Zr-PILC. The H₂O₂, 4-NP and TOC time-evolution was well described by a kinetic model based on TOC lumps in three blocks, considering the initial TOC (corresponding to 4-NP), the production of oxidizable intermediates and the formation of refractory products.

• Journal of the Korean Chemical Society
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• v.1 no.1
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• pp.20-22
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• 1949

最近 2-Amino-1-nitrophenol 및 Alkyl ether의 甘味에 對한 News가 傳하여지고 있어 特히 n-Propylether는 의 4,000培의 甘味를 가졌다고한다. 本報에서는 그 合成條件을 檢사하였다. 同時에 2-Amino-4-nitro-toluene 2-Amino-4-nitro benzoic acid를 合成하여 그 甘味를 試驗하였다.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.3981-3986
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• 2012

Anatase nanocrystalline and its tungsten-doped (0.4, 2, and 4 mol %) powders have been synthesized by microwave irradiation through hydrolysis of titanium tetra-isopropoxide (TIP) in aqueous solution. The materials are characterized by XRD, Raman, SEM-EDX, TEM, FT-IR and UV-vis techniques. The nanocrystalline $TiO_2$ particles are 30 nm in nature and doping of tungsten ion decreases their size. As seen in TEM images, the crystallites of W (4 mol %) doped $TiO_2$ are small with a size of about 10 nm. The photocatalytic activity was tested on the degradation of 4-nitrophenol (4-NP). Catalytic activities of W-doped and pure $TiO_2$ were also compared. The results show that the photocatalytic activity of the W-doped $TiO_2$ photocatalyst is much higher than that of pure $TiO_2$. Degradation decreases from 96 to 50%, during 115 min, when the initial 4-NP concentration increases from 10 to 120 ppm. Maximum degradation was obtained at 35 mg of photocatalyst.

• Bulletin of the Korean Chemical Society
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• v.33 no.3
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• pp.906-910
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• 2012

Hollow gold-silver bimetallic nanoparticles (AuAg-HNPs) have been synthesized and their optical and structural properties were characterized. Initially Ag nanoparticles (Ag-NPs) were prepared using poly(ethylenimine) (PEI) as a reducing and a stabilizing agent simultaneously. AuAg-HNPs could then be synthesized via galvanic replacement reaction in a PEI aqueous solution by reacting sacrificial Ag template with a precursor compound of Au, i.e., $HAuCl_4$. Due to the presence of abundant amine functional groups in PEI, which could act as the dissolving ligand for AgCl, the precipitation problem of $Ag^+$ in the presence of Cl from $HAuCl_4$ salt was avoided. On this basis, the relatively high concentrations of $HAuCl_4$ and PEI-stabilized Ag nanoparticles could be used for the fabrication of AuAg-HNPs. Because of their increased surface areas and reduced densities, the AuAg-HNPs were expected and confirmed to outperform their solid counterparts in applications such as catalysis for the reduction of 4-nitrophenol in the presence of $NaBH_4$.