Ferrous modified selenium sol for inhibiting accumulation of cadmium and arsenic in rice and preparation method and application thereof

A method of preparing a ferrous modified selenium sol for inhibiting accumulation of cadmium and arsenic in rice, comprising:

• (1) adding an iron-containing compound and a selenium-containing compound to water, and stirring and dissolving to obtain a mixed solution containing iron and selenium;
• (2) adding a reductant to the mixed solution containing iron and selenium obtained in step (1) under the condition of a water bath at 35° C. to 85° C., stirring for 5-15 minutes, adding carbonate when no more precipitation is generated, continuing to stir for 5-15 minutes until no more precipitation is generated, filtering, taking the precipitation, and washing to obtain the precipitation of elemental selenium and ferrous carbonate;
• (3) adding an emulsifier to a citric acid buffer solution to obtain an emulsified citric acid buffer solution;
• (4) adding the precipitation of the elemental selenium and ferrous carbonate obtained in step (2) to the emulsified citric acid buffer solution obtained in step (3) under the condition of a water bath at 25° C. to 55° C., and stirring to obtain a sol system;
• and
• (5) evaporating to concentrate the sol system obtained in step (4), and adjusting the pH to 4.5-8.5 to obtain a ferrous modified selenium sol for inhibiting the accumulation of cadmium and arsenic in rice, wherein the content of selenium in the ferrous modified selenium sol is 0.25% to 2.5% (w/v), and the content of iron is 2.5% to 7.5% (w/v).