Acknowledgements

The authors are deeply indebted to Shonan Factory of Tanaka Kikinzoku Kogyo Co. Ltd. and Western Mongolian Metals Co. Ltd. for the kind donation of the samples of printed circuit boards of spent mobile phones and Mongolian gold ore, respectively. We also indebted to Miss Kumiko Kajiyama, Miss Miyuki Matsueda, Miss Sayaka Yamada, Mr. Minoru Abe, Jun-ichi Inoue for their assistance in adsorption and recovery tests.

Elements of Bioeconomy
