TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: The step (b) involves mixing graphene oxide solution and sulfur dopant in a mass ratio of 1:10-10:1 uniformly, adding obtained mixture to pressure reactor, allowing hydrothermal reduction reaction to occur at 120-200 degrees C for 3-24 hours, washing obtained product, freezing washed product at -80 degrees C to -10 degrees C, and lyophilizing sulfur-doped graphene foam at -60 degrees C to -40 degrees C and 2-10 Pa for 6-24 hours. The step (a) involves adding and mixing suitable amount of graphite powder, potassium persulfate, concentrated sulfuric acid and phosphorus pentoxide, reacting obtained mixture in water bath, cooling obtained product to room temperature, diluting the product using deionized water, filtering solution, washing filtrate, drying washed filtrate to obtain pre-oxidized graphite powder, adding concentrated sulfuric acid to the pre-oxidized graphite powder, stirring obtained solution, adding potassium permanganate, deionized water and hydrogen peroxide to the solution, washing product using diluted hydrochloric acid, filtering solution to obtain graphene oxide, performing dialysis using water, and subjecting obtained solution to ultrasonication to obtain graphene oxide solution. The washing is performed using detergent. The method further involves adding an aqueous solution of reducing agent to the sulfur-doped graphene foam, allowing reaction to occur at 70-90 degrees C for 3-24 hours, washing obtained product, freezing washed product at -80 degrees C to -10 degrees C, and lyophilizing the product at -60 degrees C to -40 degrees C and 2-10 Pa for 6-24 hours. Preferred Process: The recycling is performed using washing agent chosen from aqueous solution of thiourea, aqueous solution of sodium edetate, ethanol, acetone and hydrochloric acid. Preferred Components: The graphene oxide solution is a monodispersion of graphene oxide, where pH and ionic strength of the monodispersion are not adjusted. The reducing agent is chosen from hydrazine hydrate, vitamin C and sodium thiosulfate. The filter material is 50-300 meshes filter screen, filter paper, filter membrane or gauze.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The sulfur dopant is small molecular compounds containing mercapto group chosen from cysteine, cystine, thioglycolic acid, mercaptoethanol and mercaptopropionic acid. The detergent is chosen from water, ethanol and acetone.