Title: The caesium and strontium adsorption properties of bamboo charcoal-containing concrete blocks

Authors: Soichiro Matsubara; Shingo Hayakawa; Yusuke Sumi; Syo Yamamoto; Norihisa Kawamura; Toru Nonami

Addresses: Department of Information Science, Graduate School of Chukyo University, 101-2, Yagotohonmachi, Nagoya Showa-ku, Aichi, Japan ' Department of Information Science, Graduate School of Chukyo University, 101-2, Yagotohonmachi, Nagoya Showa-ku, Aichi, Japan ' Department of Mechanical and Systems Engineering, Chukyo University, 101-2, Yagotohon-machi, Nagoya-shi Showa-ku, Aichi, Japan ' Institute Advanced Studies in Artificial Intelligence, Chukyo University, 101 tokodachi, kaizu-cho, Toyota-shi, Aichi, Japan ' Institute Advanced Studies in Artificial Intelligence, Chukyo University, 101 tokodachi, kaizu-cho, Toyota-shi, Aichi, Japan ' Department of Information Science, Graduate School of Chukyo University, 101-2, Yagotohonmachi, Nagoya Showa-ku, Aichi, Japan

Abstract: The Fukushima Daiichi Nuclear Power Plant accident was caused by the Great East Japan Earthquake that occurred in March 2011 in Japan. Large amounts of radioactive materials (radioactive caesium, radioactive strontium, radioactive tritium and radioactive iodine.) were released from the power plant into ecosystem components such as air, soil, and water. One way to use bamboo is to produce bamboo charcoal, which is used to purify water and condition soil. Its minerals and adsorption properties are also used for soil conditioning, humidity regulation, water purification, and as electromagnetic shield material. It has also been discovered that bamboo charcoal has a high capacity to adsorb caesium and strontium. The objective of the research described herein was to develop materials that can efficiently recover radioactive substances that exist in water. It is because caesium and strontium are scattered a lot and bamboo is inexpensive, a ubiquitous and harmless material and excellent in adsorption performance. We fabricated concrete blocks mixed with bamboo charcoal and assessed their capacity to adsorb caesium and strontium. Bamboo charcoal and cement were mixed at a 1 : 1 weight ratio and water was added to the mixture. After drying for a day, the hardened mixture was formed into concrete blocks containing bamboo charcoal. Scanning electron microscopy was performed, and factors such as pH and thermal change of the samples were investigated. To study the adsorption capacity of the samples, 1.00 g of the samples was immersed in 100 mL of a 10.0 mg/L caesium solution and strontium solution. After an hour, the concentration of caesium dropped by 40.3% and strontium by 83.1%, indicating that concrete blocks containing bamboo charcoal had a high capacity to adsorb caesium and strontium. Furthermore, the results of thermal analysis showed that the bamboo charcoal-contained in the concrete blocks burned at approximately 400°C. The boiling point of caesium is 670°C and that of strontium is 1381 °C, which suggests that weight can be reduced by burning away the bamboo charcoal at 400°C without the caesium, etc. volatilising. In addition, because the concrete blocks can be formed in various shapes, it holds promise for application in rivers, lakes, sewers.

Keywords: bamboo charcoal; concrete block; caesium; strontium; adsorption.

DOI: 10.1504/IJNT.2018.098440

International Journal of Nanotechnology, 2018 Vol.15 No.8/9/10, pp.721 - 728

Available online: 13 Mar 2019 *

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