The effect of the novel composite material LiNbO3@Fe3O4 on the nitrate removal, and Mn2+ oxidation efficiency by autotrophic denitrification strain Achromobacter sp. A14 was investigated in this study. The optimum conditions were tested by using five levels of initial Mn2+ concentrations (40, 60, 80, 100 and 120 mg/L), initial pH (5.0, 6.0, 7.0, 8.0 and 9.0) and temperature (20, 25, 30, 35 and 40°C). A maximal nitrate removal ratio of nearly 100% and a maximal Mn2+ oxidation ratio of 71.59% were simultaneously achieved at pH 7.0, 80 mg/L Mn2+ and 30°C by bacteria A14 with 300 mg/L LiNbO3@Fe3O4 as catalytic material. Biomaterial cycle testing indicated that the denitrification efficiency of bacteria A14 with LiNbO3@Fe3O4 remained steady after 10 batches.
Keywords: Denitrification; LiNbO3@Fe3O4 biomaterial; Mn(II) oxidation; biomaterial cycle.