Modified Crushed Oyster Shells for Fluoride Removal from Water.

ABSTRACT: Elevated concentrations of fluoride ions (F-) in natural groundwater are a worldwide problem. Discarded oyster shells were ground to ?100?µm particle size to produce oyster shell powder (OS). A subset of the OS was heated to produce calcined oyster shell (COS). A subset of the COS was further treated with 1?M phosphoric acid to produce phosphoric-acid-treated oyster shell (POS). OS and COS were combined with phosphoric acid (1.6?mM and 3.2?mM) to produce OS?+?P (oyster shell with phosphoric acid) and COS?+?P (calcined oyster shell with phosphoric acid). OS and COS removed 46% and 50% (10?g/L of sorbent dose) but POS, OS?+?P and COS?+?P removed 96%, 100% and 76% (1?g/L of sorbent dose) when the initial concentration of fluoride was 10?mg/L. The sorption kinetics of POS, OS?+?P and COS?+?P followed second-order reaction rates, and sorption isotherms of all sorbents were well-described by the Freundlich sorption isotherm. These results indicate that oyster shells can be an effective sorbent for fluoride removal, with the added benefit of re-use of a waste product.

SUBMITTER: Kim W 

PROVIDER: S-EPMC7113297 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature