Aluminum-salt inactivating agents are extensively applied to the restoration of lakes polluted by internal phosphorus (hereinafter referred to as "P"). However, there is a lack of micromechanism information regarding the sediment P cycle and its interactions with aluminum salts, which has restricted the engineering applications of aluminum salts. In this study, a sediment core incubation system was used to simulate the influence of aerobic and anaerobic conditions on the effectiveness and stability of aluminum-modified clay (AMC). This study also investigated the millimeter-scale dynamics of P across the sediment-water interface (SWI) using the HR-Peeper and DGT techniques. According to the results, sediment P release mainly occurred under anaerobic conditions. When the incubation system was in an anaerobic state, AMC effectively reduced the internal-P loading. In pore water, there was a positive correlation between soluble Fe and SRP, suggesting that the reductive dissolution of Fe-P constituted the main mechanism of sediment P release. After with dosing AMC, the concentrations of SRP and labile P in the capping layer both dropped abruptly to low levels and the content of Al-P in surface sediments rose, suggesting that AMC had strongly adsorbed phosphates, formed inert Al-P and blocked the phosphate exchange between pore water and overlying water. This study elaborated on the micromechanism of the control of sediment internal P input by AMC and revealed that Al-P precipitation constituted the main mechanism of the inhibition of sediment P release by aluminum-salt inactivating agents. The research findings have a great significance for guiding field applications of aluminum-salt inactivating agents. (C) 2018 Elsevier Ltd. All rights reserved. Publication name | CHEMOSPHERE, 215 657-667; 10.1016/j.chemosphere.2018.10.095 JAN 2019 | Author(s) | Wang, Jingfu; Chen, Jingan; Chen, Quan; Yang, Haiquan; Zeng, Yan; Yu, Pingping; Jin, Zuxue | Corresponding author(s) | WANG Jingfu wangjingfu@vip.skleg.cn Chinese Acad Sci, Inst Geochem, State Key Lab Environm Geochem, Guiyang 550002, Guizhou, Peoples R China. | View here for the details
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