著者

Isao SHITANDA Kengo KUMAGAI Chihomi TAKAMI Yoshinao HOSHI Masayuki ITAGAKI

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.89, no.1, pp.54-58, 2021-01-05 (Released:2021-01-05)

参考文献数

22

被引用文献数

1 2

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Tin-plated copper tubes have been widely used in cold and hot water service systems. However, leakage accidents caused by pitting corrosion can occur in such tubes; therefore, it is necessary to evaluate the effects of major environmental factors on the occurrence of local corrosion to ultimately suppress this corrosion. In the present study, the anodic polarization curves of a tin-coated copper electrode were measured in simulated freshwater containing Cl−, SO42−, and HCO3−. The anodic current increased suddenly and sharply due to the breakdown of the passive layer and the initiation and growth of pitting generation at the pitting potential. The pitting potential shifted to a more negative direction with increasing Cl− and SO42− concentrations. In contrast, the pitting potential shifted to more noble potentials upon increasing the HCO3− concentration, indicating that HCO3− has an inhibitory effect on pitting attack by Cl− and SO42−. The quantitative relationship between each anion concentration and the pitting potential was determined by multiple regression analysis. A plot of the pitting potential predicted from the created regression equation and the measured values of the pitting potential showed a positive linear relationship.

著者

Keisuke KIKUCHI Tomohiro YASUE Rie YAMASHITA Satoshi SAKURAGAWA Masao SUDOH Masayuki ITAGAKI

出版者

The Electrochemical Society of Japan

雑誌

Electrochemistry (ISSN:13443542)

巻号頁・発行日

vol.81, no.10, pp.828-832, 2013-10-05 (Released:2013-10-05)

参考文献数

26

被引用文献数

4 14

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Large amounts of spent coffee grounds (SCGs) are generated all over the world. Since SCGs contain a lot of carbon and inherently has a porous structure, SCGs are considered to be a valuable industrial resource by carbonization. According to our previous research, it was apparent that the specific surface area of SCGs-derived carbon was greatly improved by potassium hydroxide (KOH) activation. In this research, we prepared an electric double layer capacitor (EDLC) using SCGs-derived carbon activated with KOH, and compared them to phenol resin-derived activated carbon (MSP-20, Kansai Coke and Chemicals Co., Ltd.), which is commonly used as a reference material in EDLC research. Electrodes were prepared by mixing 80 wt% activated carbon, 10 wt% carbon black and 10 wt% polytetrafluoroethylene (PTFE) and the electrolyte used was 1 M triethylmethylammonium-tetrafluoroborate (TEMA-BF4)/propylene carbonate (PC). The capacitive performance was evaluated by a constant current charge-discharge cycle measured with various electrical current loads from 5 to 150 mA/cm2. Although the capacitance of SCGs-derived carbon activated with KOH was inferior to that of MSP-20 at low current load density, it had high capacitance in high rate charge-discharge cycles. This suggests that the EDLC consisting of SCGs-derived activated carbon electrodes is superior to MSP-20 in capacitance retention rate when used at a high electric current density.

著者

Isao Shitanda Tasuku Yamaguchi Yoshinao Hoshi Masayuki Itagaki

出版者

(社)日本化学会

雑誌

Chemistry Letters (ISSN:03667022)

巻号頁・発行日

pp.130681, (Released:2013-08-24)

被引用文献数

17

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A fully screen-printed electrode chip was fabricated for glucose detection. The utility of the screen-printed electrode chip based on a Japanese paper was demonstrated through the determination of glucose using the reaction of glucose oxidase with tetrathiafulvalene. The calibration curve showed good linearity in the concentration range 10 to 100 mM, with a slope of 0.055 μA mM−1. The paper-based electrode chip is potentially applicable for point-of-care monitoring because it is easy to use, inexpensive, and readily disposable.