Zang Yue, Yan Pan, Ren Tongtong, Ding Shaoxuan, Sun Shanshan, Shen Jian, Wang Xinze, He Shengbing
School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, PR China; Yunnan Dali Research Institute of Shanghai Jiao Tong University, Dali 671000, PR China.
School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, PR China.
Sci Total Environ. 2024 Dec 15;956:177327. doi: 10.1016/j.scitotenv.2024.177327. Epub 2024 Nov 6.
As the potential causes of eutrophication, nitrogen (N) and phosphorus (P) in sediments have received wide attention. However, few of the in-situ sediment remediation methods can achieve simultaneous N removal and P stabilization in sediments. In this study, different impacts on N, P and organic matter (OM) properties of sediments and overlying water with different proportions of calcium peroxide (CaO) coupling with zero-valent iron (ZVI) were explored through incubation experiments. Compared with CaO or ZVI alone, the total nitrogen (TN) removal ratios in the whole system at 0.6 g/kg CaO coupled with 40 g/kg ZVI increased by 167.91% and 152.04%, respectively. Due to the enhancement of oxidation, the removal efficiency of OM from sediments increased by 118.51%. Meanwhile, the genera related to denitrification (e.g., Anaerobacillus, Haloplasma, and Clostridium_sensu_stricto_8) were also enriched in this coupling group, which was due to the enhanced decomposition of OM and the electron donation of ZVI. In addition, CaO coupled with ZVI stabilized P through chemical precipitation, which converted organic phosphorus (Org-P) into more stable calcium bounded P (Ca-P) in sediments. Hence the coupling effectively increased total P (TP) content in sediments and reduced P concentration in water.
作为富营养化的潜在成因，沉积物中的氮（N）和磷（P）受到了广泛关注。然而，很少有原位沉积物修复方法能够实现沉积物中氮的去除和磷的稳定化。在本研究中，通过孵化实验探究了不同比例的过氧化钙（CaO）与零价铁（ZVI）耦合对沉积物及上覆水中氮、磷和有机质（OM）性质的不同影响。与单独使用CaO或ZVI相比，在0.6 g/kg CaO与40 g/kg ZVI耦合时，整个系统中的总氮（TN）去除率分别提高了167.91%和152.04%。由于氧化作用增强，沉积物中OM的去除效率提高了118.51%。同时，与反硝化作用相关的属（如厌氧芽孢杆菌属、盐质菌属和严格梭菌属8）在该耦合组中也得到了富集，这是由于OM分解增强和ZVI的电子供体作用。此外，CaO与ZVI通过化学沉淀使磷稳定化，将沉积物中的有机磷（Org-P）转化为更稳定的钙结合磷（Ca-P）。因此，这种耦合有效地增加了沉积物中的总磷（TP）含量并降低了水中的磷浓度。
