Reducing nitrate in groundwater by denitrifying bacteria combined with nanoiron-based materials
纳米铁系材料与反硝化细菌复合去除地下水硝酸盐氮研究

Three nanoiron-based particles, Fe, Fe/Ni and sodium oleate-coated Fe, were synthesized by liquid-phase reduction methods and then integrated with denitrifying bacteria to remove nitrate from groundwater. Batch experiments were carried out to examine the removal rate of nitrate and the final nitrogen transfomation products in these particle-bacteria systems. Also, the total RNA content in these systems was measured to evaluate the toxicity of nanoiron-based particles on the integrated bacteria. The results showed that almost 100% removal of nitrate was reached within 6 days in the Fe/Ni nanoparticle-bacteria system, and the ratio of ammonium to TN was 69% in the final products. Both nano-scale Fe and sodium oleate-coated Fe particle-bacteria systems took 9 days to complete 100% removal of nitrate, producing 52% and 16% ammonium, respectively. The total RNA of the integrated bacteria decreased in content by 93%, 40% and 34% in the Fe/Ni, Fe and sodium oleate-coated Fe nanoparticle-bacteria systems respectively, which suggested the toxicity of these nanoparticles to denitrifying bacteria should be in the sequence: nano-scale Fe/Ni > nano-scale Fe > sodium oleate-coated Fe.