Removal of Cr (Vi) from aqueous solution by adsorption on the natural and activated fluorapatite

Abstract

The present paper to study the immobilization of chromium ions Cr(VI) in an aqueous solution by adsorption on a natural phosphate (PN) and activated (PA).The natural phosphate whose main component is fluorapatite Ca 10 (PO 4 ) 6 F 2 . The study of the retention of chromium (VI) ions on natural and activated flourapatite is conditioned by several parameters namely the pH. The initial concentration of metals and the contact time. Results obtained showed that after 40 minutes of contact. The results obtained showed that after 40 minutes of contact, the elimination of chromium (VI) was maximum with a yield of 67.4% for the natural flouraptite and 75.9% for the activated phosphate. Increasing the adsorbent dose (0.5 to 1 g/l) makes it possible to improve the chromium removal efficiency with an initial concentration (10 mg/l) / l. The efficiency of removing chromium (VI) by each adsorbent decreases with the increases of the initial chromium content (2 to 10 mg / l). PH has a significant effect on the retention rate of chromium (VI). The efficiency of removing Cr (VI) is interesting for acid pH. Moreover, the adsorption of this compound we described by the kinetic models of Langmuir and Freundlich.