Abstract:

With the ongoing developments in the graphene industry, the discharge of wastewater is increasing. It has the characteristics of strong acidity and high concentration of fluoride and metal ions. In this experiment, graphene simulated wastewater were treated by four methods, including single coagulation, neutralization coagulation, coagulation flocculation, and neutralization coagulation and flocculation. These methods were compared to remove contaminants such as fluoride and metal ions. The ion content and sediment in the wastewater were analyzed using ion chromatography and X-ray powder diffraction. The results show that the combination of sodium hydroxide, calcium hydroxide, and flocculant has the best fluoride removal effect. The removal rates of fluoride and metal ions reached 98% and 99.5%, respectively. Compared with the traditional process, the sediment is reduced by over 50%. The experiment was easily operated and observed. The experimental content highlights that combining practice and theory methods enriches the teaching design of experimental courses and guides students to understand the current situation of industrial production, improve their awareness of environmental protection, and master the usage of chemical software and ability of data analysis and processing. This satisfies the requirements of cultivating students' comprehensive ability in applied undergraduate colleges.

Key words: Graphene wastewater, Coagulation sedimentation, Flocculent sedimentation, Comprehensive experiment