Abstract
Granulated coal ash (GCA) is an alkaline material made from fly ash, which mainly comprised of SiO2, Al2O3, and CaO. It has been reported that scattering GCA on sea bottom sediment can suppress the release of nutrient salts from the sediment into bottom water. This study is aiming at revealing mechanisms of phosphate immobilization by GCA through laboratory experiments. The results showed that phosphate immobilization occurred when pH was higher than 10. Therefore, it is thought that phosphate immobilization occurs at the GCA surface or in the scattered-GCA layer. The dissolution of GCA components may continuously invoke the high pH of surrounding environment of GCA, leading to the phosphate immobilization.
