Contrasting Perfluorooctanoic Acid Removal by Calcite Before and After Heat Treatment

Le résumé fourni par la source

Calcites before and after calcination at 1000 °C were evaluated for their potential removal of perfluorooctanoic acid (PFOA) from water. After heat treatment, the PFOA sorption capacity increased by 25%, from 3.2 to 3.9 mg g−1, and the affinity increased by 2.7 times, from 0.03 to 0.08 L mg−1. Kinetically, the initial rate, rate constant, and equilibrium sorption were 8.7 mg g−1 h−1, 2.6 g mg−1 h−1, and 1.8 mg g−1 for heat treated calcite, in comparison to 6.4 mg g−1 h−1, 3.1 g mg−1 h−1, and 1.4 mg g−1 for calcite without heat treatment. X-ray diffraction analyses showed phase changing from calcite to calcium oxide after calcination. However, after contact with PFOA solutions for 24 h, the major phase changed back to calcite with a minute amount of Ca(OH)2. These results suggest that using raw cement materials derived from heat treatment of limestone may be a good option for the removal of PFOA from water. Thus, further studies are needed to confirm this claim.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.