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MnO2/graphene supported on Ni foam: an advanced electrode for electrochemical detection of Pb(II)
Liu Rui,Zhang Chao-Jun,Han Xue,Wu Tian-Heng,Liu Ri-Jia,Sun Yuan,Jin Shuang 한국탄소학회 2023 Carbon Letters Vol.33 No.3
Graphene-derived materials are an excellent electrode for electrochemical detection of heavy metals. In this study, a MnO2/graphene supported on Ni foam electrode was prepared via ultrasonic impregnation and electrochemical deposition. The resulting electrode was used to detect Pb(II) in the aquatic environment. The graphene and MnO2 deposited on the Ni foam not only improved active surface area, but also promoted the electron transfer. The electrochemical performance towards Pb(II) was evaluated by cyclic voltammetry (CV) and square wave anodic stripping voltammetry (SWASV). The prepared electrode exhibited lower limit of detection (LOD, 0.2 μM (S/N = 3)) and good sensitivity (59.9 μAμM−1) for Pb(II) detection. Moreover, the prepared electrodes showed good stability and reproducibility. This excellent performance can be attributed to the strong adhesion force between graphene and MnO2, which provides compact structures for the enhancement of the mechanical stability. Thus, these combined results provide some technical considerations and scientific insights for the detection of heavy metal ions using composite electrodes.
Photocatalytic degradation of tetracycline with Fe3O4/g-C3N4/TiO2 catalyst under visible light
Liu Rui,Zhang Xin,Han Xue,Sun Yuan,Jin Shuang,Liu Ri-jia 한국탄소학회 2024 Carbon Letters Vol.34 No.1
Fe3O4/g-C3N4/TiO2 catalyst has been fabricated using a simple ultrasonic method with high photocatalytic activity. The morphology, structure and optical properties of Fe3O4/g-C3N4/TiO2 were systematically investigated by a variety of characterization techniques. The optimum degradation conditions were investigated by degrading tetracycline (TC) under visible light irradiation. The results showed that the degradation efficiency was the highest when the initial TC concentration was 5.0 mg/L, the pH value was 11 and the catalyst dosage was 1.0 g/L. After 100 min of visible light irradiation, the degradation efficiency of TC achieved at 73.61%, which was 1.64 and 1.19 times that of g-C3N4 and Fe3O4/g-C3N4, respectively. Moreover, Fe3O4/g-C3N4/TiO2 had good stability and recyclability. The results of capture experiments showed that ‧O2− and ‧OH were the main active species during the photocatalytic process, and a possible photocatalytic reaction mechanism of Fe3O4/g-C3N4/TiO2 catalyst was proposed. This study provides a new way to improve the photocatalytic performance of g-C3N4, which has great potential in degrading pollutants such as antibiotics in wastewater.
식용 해조류 톳(Hizikia fusiformis) 유래 항산화 활성분획물의 산화적 손상이 유도된 인간피부섬유아세포 보호 효과
Yong Ri Cui,김현수,제준건,Lei Wang,오재영,Liu Jia,전유진 한국수산과학회 2019 한국수산과학회지 Vol.52 No.1
We investigated the protective effects of antioxidant fractions from a 70% ethanolic extract of Hizikia fusiformis in human dermal fibroblasts (HDFs). Powdered H. fusiformis was extracted with 70% ethanol and then partitioned into three fractions according to polarity using n-hexane (HFH), chloroform (HFC), and ethyl acetate (HFEA). Antioxidant activity was observed in HFEA at 0.66 mg/mL based on the half maximal inhibitory concentration (IC50) of 1,1-diphenyl-2-picrylhydrazyl (DPPH), and at 0.24 mg/mL based on alkyl radical scavenging. The protective effects of the HFEA antioxidant fraction against 2,2-azobis-(2-amidinopropane) dihydrochloride (AAPH)-damaged HDFs and the expression of Type I procollagen in HDFs were examined. HFEA caused the proliferation of HDFs with and without AAPH treatment and protected against AAPH damage to HDFs in a dose-dependent manner (50-200 μg/mL). This implies that the antioxidant properties of the fractions depended on their proliferative and protective effects. The HFEA antioxidant fraction had significant effects and caused the dose-dependent expression of Type I procollagen, an important anti-wrinkle protein, in HDFs. In conclusion, antioxidant substances in H. fusiformis were found in the ethyl acetate fraction, and the resulting HFEA may have cosmetic applications.