▎ 摘　　要

NOVELTY - Removal of iron ion in water by nitrogen and sulfur-modified graphene electrode involves adding L-cysteine to a dispersion of graphene oxide and deionized water, homogeneously dispersing, heating, soaking the product in distilled water, freeze-drying, dispersing with a pre-formulated polyvinyl alcohol solution, coating the mixture on a hard paper, freeze-drying to obtain a nitrogen-sulfur co-doped graphene aerogel paper electrode, preparing a heavy metal ion solution, placing the paper electrode into the solution, and carrying out adsorption of iron ion by the electrode. USE - Removal of iron ion in water by nitrogen and sulfur-modified graphene electrode (claimed). ADVANTAGE - The method enables simple and rapid removal of iron ion in water by nitrogen and sulfur-modified graphene electrode, which has high adsorption efficiency. The nitrogen and sulfur-modified graphene electrode is prepared by a simple and environmentally-friendly method. DETAILED DESCRIPTION - Removal of iron ion in water by nitrogen and sulfur-modified graphene electrode involves ultrasonically dispersing graphene oxide in deionized water for 10-30 minutes, adding L-cysteine, homogeneously dispersing, stirring the dispersion evenly, heating the mixture in a water bath at 95 degrees C for 2 hours, soaking the reaction product in distilled water for 2-3 days, freeze-drying to obtain a nitrogen-sulfur co-doped graphene aerogel material, mixing the nitrogen-sulfur co-doped graphene aerogel material with a pre-formulated polyvinyl alcohol solution, dispersing to obtain a paste-like dispersion, removing 0.1-0.4 mL dispersion, evenly coating on a hard paper, freeze-drying to obtain a nitrogen-sulfur co-doped graphene aerogel paper electrode, preparing a heavy metal ion solution, adding the solution into an electric adsorption vessel, placing the paper electrode into the vessel, carrying out adsorption of iron ion on the paper electrode, monitoring the conductivity by a conductivity meter, removing the voltage on the electrode after adsorption of heavy metal ions, restoring the conductivity of the solution to near the initial value and regenerating desorption of the electrode. The adsorption of heavy metal iron ion is carried out in a three-electrode system. The three-electrode system comprises a paper electrode as the working electrode, a platinum sheet electrode as a counter electrode and a calomel electrode is a reference electrode. The adsorption of the paper electrode is in equilibrium state, when the conductivity is constant.