SELENIUM-DOPED NANO SILICA SOL USED FOR PRODUCING SELENIUM-ENRICHED RICE AND CAPABLE OF SUPPRESSING ABSORPTION AND ACCUMULATION OF HEAVY METALS IN PADDY RICE AND PREPARATION METHOD THEREFOR

摘要

Selenium-doped nano silica sol used for producing selenium-enriched rice and capable of suppressing absorption and accumulation of heavy metals and a preparation method therefor. The selenium-doped nano silica sol has a special structure and a special function and is formed by using nano silica sol as a carrier, sodium selenite and the like as raw materials, vitamin C and the like as reducing agents, and polyvinylpyrrolidone and the like as emulsifiers, and doping and dispersing selenium into the silica sol according to a particular proportion. The prepared selenium-doped nano silica sol has high stability and high concentration, and is uniform and clear; and the silicon dioxide content can reach 20% or more, the selenium content can reach 1% or more, and the content of impurities is low. The pH of the selenium-doped nano silica sol is close to neutral; selenium is dispersed into silicon dioxide colloid in the form of nano particles; the particle diameter of the colloid is smaller than 50 nm. After being sprayed to leaf surfaces, the selenium-doped nano silica sol can significantly promote the growth of crops, suppress absorption and accumulation of arsenic and cadmium by the crops, and increase the selenium content of the crops. The selenium-doped nano silica sol has no toxic or side effects on the crops and is safe to use.