Preparation method of modified activated carbon for deeply removing trace phosphorus and boron impurities in electronic-grade chlorosilane

The invention provides a preparation method of modified activated carbon for deeply removing trace phosphorus and boron impurities in electronic-grade chlorosilane, which comprises the following steps: S1, oxidation modification: preparing activated carbon raw materials into formed activated carbon, and then putting the formed activated carbon into an oxidizing agent for full contact, so that the oxidizing agent fully enters the activated carbon and is subjected to oxidation reaction with the activated carbon components to obtain modified activated carbon; the inner structure of the activated carbon is adjusted, the specific surface area is increased, and the inner hole structure is improved; s2, reduction modification: putting the oxidized activated carbon obtained in the step S1 into a nitrogen-containing reducing agent for full contact, so that the nitrogen-containing reducing agent fully enters the activated carbon and is subjected to a reduction reaction with activated carbon components, the surface of t