Biogas and calcite handling in calcium fluoride precipitation from aqueous solution guided by thermodynamic simulation with PHREEQC.

In this innovative study, biogas has been associated with calcium carbonate [CaCO] to promote the precipitation of fluorite, aiming at the treatment of wastewater with high content of fluoride. The work associates distinct sources of calcium and CO for the precipitation of fluorite according to previous simulation with the free software PHREEQC. Considering the reaction at equilibrium, the minimal predicted Ca dosage was 215 mg/L, lower than the 430 mg/L that was experimentally determined, independent of Ca source.

Cow bones char as a green sorbent for fluorides removal from aqueous solutions: batch and fixed-bed studies.

Cow bone char was investigated as sorbent for the defluoridation of aqueous solutions. The cow bone char was characterized in terms of its morphology, chemical composition, and functional groups present on the bone char surface using different analytical techniques: SEM, EDS, N-BET method, and FTIR. Batch equilibrium studies were performed for the bone chars prepared using different procedures.