The synergy of Ca(NO) and CaO can effectively reduce the risks of secondary pollution caused by nitrate escape and release. However, the timing and suitable dosage of Ca(NO) and CaO during the synergistic interaction have not been fully investigated. In this work, we separated acid volatile sulfides (AVS) oxidation and ferrous iron oxidation by controlling the dosage of Ca(NO). Results indicated that at a low ratio, there was an obvious competitive relationship between AVS oxidation and ferrous iron oxidation, and sulfide was oxidized prior to ferrous iron. More efficient AVS and ferrous iron oxidation was achieved using Ca(NO) to oxidize AVS and CaO to oxidize ferrous iron. After the treatment with Ca(NO) and CaO, the anaerobic reduction environment of the sediment was modified, and the metabolic pathways dominated by sulfate respiration and methanogenic metabolism in the sediment were gradually converted to nitrate-reduction and dissimilatory iron reduction. The synergy of Ca(NO) and CaO could reduce 99.61 % CH compared with control check and could reduce 81.66 % NO compared with adding Ca(NO) only. Furthermore, the biodegradability of organic matter was improved due to the transformation of stubborn organic matter. These results provide valuable guidance for applying Ca(NO) and CaO in sediment remediation.

中文翻译：

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Ca(NO3)2-CaO2对沉积物微生态改善的协同作用：硫和二价铁的转化及改善机制


Ca(NO)和CaO的协同作用可以有效降低硝酸盐逃逸和释放造成的二次污染风险。然而，Ca(NO)3和CaO在协同相互作用过程中的时机和合适剂量尚未得到充分研究。在这项工作中，我们通过控制Ca(NO)的用量来分离酸性挥发性硫化物(AVS)氧化和亚铁氧化。结果表明，在低配比时，AVS氧化与二价铁氧化存在明显的竞争关系，且硫化物先于二价铁被氧化。使用 Ca(NO) 氧化 AVS 和 CaO 氧化二价铁，实现了更有效的 AVS 和二价铁氧化。经过Ca(NO)和CaO处理后，沉积物的厌氧还原环境得到改变，沉积物中以硫酸盐呼吸和产甲烷代谢为主的代谢途径逐渐转变为硝酸盐还原和异化铁还原。 Ca(NO)和CaO的协同作用与对照相比可以减少99.61%的CH，与单独添加Ca(NO)相比可以减少81.66%的NO。此外，由于顽固有机物的转化，有机物的可生物降解性得到提高。这些结果为Ca(NO)和CaO在沉积物修复中的应用提供了有价值的指导。