Solar sewage purification aerogel based on waste paper and graphite, and preparation method thereof

The invention discloses a preparation method of a solar sewage purification aerogel based on waste paper and ball-milled graphite. The preparation method comprises the following steps: (1) adding graphite powder, N-methylpyrrolidone (NMP) and a ball milling ball into a ball-milling tank, and obtaining ball-milled graphite by a ball-milling method; (2) adding the obtained ball-milled graphite and concentrated sulfuric acid into a container, and heating for acid treatment to obtain acidified ball-milled graphite; (3) adding waste paper scraps into a mixed solution of water, NaOH and thiourea, and carrying out ball milling and freeze drying to obtain ball-milled cellulose; and (4) adding cellulose and alcohol into the obtained acid-treated ball-milled graphite dispersion, carrying out ultrasonic treatment, and carrying out freeze casting and freeze drying to obtain the ball-milled graphite/cellulose composite aerogel. The ball-milled graphite/cellulose aerogel prepared by the invention has excellent hydrophilic performance, extremely low density, extremely high porosity, extremely low thermal conductivity and controllable aerogel size and thickness, and can be used as an efficient photo-thermal water treatment material for purifying sewage and desalinating seawater.