Study on the simultaneous removal of fluoride, heavy metals and nitrate by calcium precipitating strain Acinetobacter sp. H12.

The removal properties and mechanisms of fluoride (F-) and nickel (Ni2+) were studied by biomineralizing bacteria (Acinetobacter sp. H12). The results showed that the removal ratio of F-, Ca2+ and Ni2+ reached 75% (0.031 mg·L-1·h-1), 84.96% (2.123 mg·L-1·h-1), and 56.67% (0.024 mg·L-1·h-1) after 72 h, respectively. The removal ratio of nitrate (NO3-) reached 100% (0.686 mg·L-1·h-1) after 24 h. SEM and XRD images indicated that bioprecipitation of CaF2, Ca5(PO4)3F, Ca5(PO4)3(OH), NiCO3, CaCO3 and Ni were formed, and some of these precipitation used bacteria as nucleation sites to form biological crystal seeds. N2 was the primary product in gas chromatography analysis. Meanwhile, both the fluorescence spectroscopy and fourier transform near-infrared spectroscopy analysis proved that strain H12 had good ability to remove fluoride and nickel ions simultaneously.