▎ 摘　　要

NOVELTY - Preparing nitrogen-sulphur co-doped graphene gel involves dispersing ultrasonically oxidized graphene in de-ionized water, treating ultrasonic for 10-30 minutes, dispersing uniformly, adding L-cysteine and stirring to obtain mixed solution. The obtained mixed solution is heated under water bath at 95 degrees C for 2 hours. The obtained product is placed in the distilled water for 2-3 days. The obtained product is freezed and dried to obtain nitrogen-sulphur co-doped graphene gel. The obtained product gel is mixed with pre-formulated polyvinyl alcohol solution to form paste dispersion. USE - Method for preparing nitrogen-sulphur co-doped graphene gel for removing magnesium ions in water (claimed). ADVANTAGE - The method enables to prepare nitrogen-sulphur co-doped graphene gel in simple and eco-friendly manner and has high water adsorption efficiency that solves the problem of high hardness in the water. DETAILED DESCRIPTION - Preparing nitrogen-sulphur co-doped graphene gel involves dispersing ultrasonically oxidized graphene in de-ionized water, treating ultrasonic for 10-30 minutes, dispersing uniformly, adding L-cysteine and stirring to obtain mixed solution. The obtained mixed solution is heated under water bath at 95 degrees C for 2 hours. The obtained product is placed in the distilled water for 2-3 days. The obtained product is freezed and dried to obtain nitrogen-sulphur co-doped graphene gel. The obtained product gel is mixed with pre-formulated polyvinyl alcohol solution to form paste dispersion. The 0.1-0.4mL paste dispersion is uniformly applied to the cardboard. The obtained cardboard is freezed and dried to obtain nitrogen-sulfur co-doped graphene gel electrode. The magnesium ion is prepared. The magnesium ion solution amount is put in the electric absorbing container containing nitrogen-sulphur co-doped graphene gel electrode for electro-adsorption magnesium ion experiment. The electro-adsorption magnesium ion experiment is used three-electrode system, paper electrode as working electrode, platinum electrode as counter electrode, calomel electrode as reference electrode. The change of conductivity meter real-time is monitored of solution and measured conductivity. The conductivity is constant and is namely as paper electrode absorption. The electrode voltage is removed on the electrical conductivity of the solution after recovery to the initial and realized the desorption regeneration electrode.