Preparation method and application of eutrophic water body sediment phosphor in-situ passivating agent

The invention discloses a preparation method and an application of a eutrophic water body sediment phosphor in-situ passivating agent. The method comprises the following steps: uniformly mixing the sodium bentonite to modified substrate with mass ratio of 1-5:1, configuring to mixed liquor or directly and uniformly sprinkling on the surface of the water body. The passivating agent can rapidly absorb dissolved inorganic phosphorus (DIP) and suspended matters through the surface sorption of the passivating agent during a settlement process, and can increase the transparency of water body; on the other hand, the passivating agent settles to the sediment surface for forming a masking layer, a physical insulation effect and a chemisorption effect can prevent the sediment from releasing phosphor in the sediment to overlying water, the purpose of in-situ controlling the releasing of sediment phosphor can be reached, thereby the phosphor content in overlying water can be minimized, and the water body eutrophication can be inhibited. The application of the passivating agent can minimize more than 80% of phosphor releasing amount, the application scope is wide, and the passivating agent is suitable for controlling and treating the release of the sediment endogenous phosphor in lake, reservoir and the like, and has the advantages of simple operation, low cost , good environmental protection benefit and the like.