▎ 摘　　要

NOVELTY - Method for preparing silica using graphene oxide waste liquid involves (i) collecting waste liquid after preparing graphene oxide, (ii) adding an organic chelating agent, chelating manganese ions, adding petroleum ether, stirring and layering to obtain an organic layer and an inorganic layer and removing the organic layer, where the obtained inorganic layer is a first acid solution, (iii) adding granular graphene obtained by reducing graphene oxide by hydrazine hydrate to the first acid solution, adsorbing manganese ions and removing the graphene adsorbed with the manganese ions to obtain a second acid solution, (iv) preparing a sodium silicate aqueous solution, dripping concentrated sulfuric acid and stirring, (v) raising the temperature, dripping the second acid solution while stirring, aging, dripping and stirring and (vi) filtering and washing and filtering, placing the filtered and washed first precipitate in an oven, drying at 100 degrees C and calcining. USE - The method is useful for preparing silica using graphene oxide waste liquid. ADVANTAGE - The method realizes the reuse of graphene oxide waste liquid, protects the environment and provides better quality of the prepared silica product. DETAILED DESCRIPTION - Method for preparing silica using graphene oxide waste liquid involves (i) collecting waste liquid after preparing graphene oxide, where the waste liquid contains potassium ions, manganese ions, sulfate ions and hydrogen ions, (ii) adding an organic chelating agent to the waste liquid, chelating manganese ions in the waste liquid, adding petroleum ether, stirring, leaving still and layering to obtain an organic layer and an inorganic layer, and removing the organic layer, where the obtained inorganic layer is a first acid solution, (iii) adding granular graphene obtained by reducing graphene oxide by hydrazine hydrate to the first acid solution, adsorbing the manganese ions in the first acidic solution using the graphene and removing the graphene adsorbed with the manganese ions using a filtering method to obtain a second acid solution, (iv) preparing an aqueous sodium silicate aqueous solution, slowly dripping concentrated sulfuric acid under continuous stirring and maintaining stirring for 15 minutes after reaction to reaches pH of 10, (v) raising the temperature to 70-90 degrees C, dripping the second acid solution to the sodium silicate solution while stirring, when the reaction reaches pH of 6-7, aging for 60-100 minutes, continuously dripping until the pH is 4-5 and stirring for 60-120 minutes to obtain a third acidic solution containing a first precipitate and (vi) filtering the first precipitate from the third acid solution and washing the first precipitate repeatedly and filtering by clean water, placing the filtered and washed first precipitate in an oven, drying at 100 degrees C and calcining.