Dual role of coal fly ash in copper ion adsorption followed by thermal stabilization in a spinel solid solution.

Coal fly ash is usually used as a cost-effective adsorbent for heavy metal removal, accumulating large amounts of spent coal fly ash that requires further disposal. In this study, fly ash that adsorbs copper with a maximum copper adsorption capacity of 48.8 mg g was further sintered at 900-1050 °C, and it was found that the copper is thermally incorporated in a spinel structure in aluminum- and iron-containing ceramic matrices provided by the fly ash.