Youichi Sakuta*, Nobuhiro Nagano*, Keiichi Tomita*, Motoomi Wakasugi*, Takayuki Saitoh*, Kazuyoshi Shimakage** and Toshimori Kitazaki***

* Hokkaido Industrial Research Institute
** Muroran Institute of Technology
*** Saneiriko Co., Ltd

+ Correspondence should be addressed to Youichi Sakuta:
(Kita 19-jo, Nishi 11-chome, Kita-ku, Sapporo 060-0819 Japan)

Abstract

Cadmium elimination from the waste products of scallop processing, which are below the regulation content is necessary to reuse these wastes as feed and fertilizer materials. In this experiment, influences of various factors on cadmium removal efficiency were examined, to decide the most suitable conditions using an electrochemical treatment method. This method consists of a cadmium leaching process from the mid-gut gland by soaking in a sulfuric acid solution, and a cadmium electrodeposition process on the cathode surface by passing an electric current through it. We have obtained the following results by using this method.

1) The grain size of the mid-gut gland has a great influence on the cadmium leaching rate, as expected. Therefore, drying and crushing the scallop waste is useful for shortening the cadmium removal treatment time, to about half as many hours as when not crushed.

2) Ti plates coated with iridium oxide and coated Pt group oxides are most suitable for anode materials when using this electrolysis method.

3) A minimum electrolytic voltage of 3.2V is required for deposition of cadmium when using this electrolysis method. Consequently, in cases of electrolysis below this electrolytic voltage, cadmium does not deposit, and conversely remelting of deposited cadmium on the cathode surface is caused.

Key words: mid-gut gland, cadmium, removal technology, feed, fertilizer, electrodeposition