▎ 摘　　要

NOVELTY - Recycling waste acid resources comprises (i) adding concentrated sulfuric acid and concentrated phosphoric acid to reaction kettle, stirring, adding potassium permanganate, adding flake graphite, stirring, intercalating graphene oxide precursor, cooling, adding water, stirring, adding hydrogen peroxide, and stirring, (ii) placing the graphene oxide slurry into a ceramic membrane filtration device, turning on pump circulation filtration, collecting the waste liquid at the filter end of the ceramic membrane to obtain spent acid 1 and graphene concentrated slurry 1, adding concentrated hydrochloric acid to the graphene concentrated slurry 1, mixing, filtering the slurry through a ceramic membrane filtration device, and collecting acid-containing wastewater, (iii) spray-drying the graphene concentrated slurry 2, (iv) heating the spent acid solution 1, distilling, crystallizing, and (v) detecting the mass ratio of sulfuric acid to phosphoric acid in the mixed concentrated acid. USE - The method is useful for preparing graphene oxide (claimed). DETAILED DESCRIPTION - Recycling waste acid resources (i) adding concentrated sulfuric acid and concentrated phosphoric acid to reaction kettle in a mass ratio of 10-15:1, stirring at 0 degrees C, adding potassium permanganate to the kettle, uniformly stirring at less than 10 degrees C, where the mass ratio of concentrated sulfuric acid to potassium permanganate is 25-30:1, adding flake graphite to the kettle, stirring at 30-60 degrees C for 15-20 hours, intercalating graphene oxide precursor, where the mass ratio of the potassium permanganate to the flake graphite is 2-4:1, cooling the intercalated graphene oxide precursor to room temperature, adding 5 degrees C water, uniformly stirring, adding hydrogen peroxide, and stirring until the color of the slurry changes from brown to bright yellow to obtain graphene oxide slurry, (ii) placing the graphene oxide slurry into a ceramic membrane filtration device, turning on pump circulation filtration, where the concentrated volume is about 1/4-1/3 of the volume of the original solution, collecting the waste liquid at the filter end of the ceramic membrane to obtain spent acid 1 and graphene concentrated slurry 1, adding concentrated hydrochloric acid to the graphene concentrated slurry 1, uniformly mixing, continuously raising purified water or recycle water, filtering the slurry through a ceramic membrane filtration device, where the conductivity to the waste end reaches below 100 mu S/cm, and collecting acid-containing wastewater to obtain spent acid 2 and graphene concentrated slurry 2, (iii) centrifugally spray-drying the graphene concentrated slurry 2 to obtain graphene oxide powder, (iv) heating the spent acid solution 1 at 100-150 degrees C under -0.08 MPa, distilling to a concentration of 80% by weight of sulfuric acid, cooling and crystallizing, draining the solid-liquid mixture to obtain filtrate 1 and crystal 1, heating the filtrate 1 at 180-220 degrees C under -0.08 MPa, distilling to a concentration of 93% by weight of sulfuric acid, cooling and crystallizing, draining the solid-liquid mixture to obtain filtrate 2 and crystal 2, where the filtrate 2 is a mixed concentrated acid, concentrating the spent acid solution 2 to the concentration of the spent acid solution 1, and distilling, concentrating and crystallizing by distillation and crystallization of waste acid solution 1, and (v) detecting the mass ratio of sulfuric acid to phosphoric acid in the mixed concentrated acid, adding concentrated sulfuric acid and concentrated phosphoric acid, adjusting to a mass ratio of concentrated sulfuric acid to concentrated phosphoric acid of 10-15:1, uniformly mixing at 0 degrees C, using in the step (i), and carrying out remaining steps as same as steps (i)-(iii).