Abstract K2S2O8 was prepared in K2SO4-H2SO4 aqueous solution as the electrolyte. Based on the reaction principle between K2SO4 and H2SO4 and the solubility of KHSO4, the preparation method of the electrolyte was improved in this paper. After improvement, the experiment takes the advantages of short time and easy operation. Moreover, the effects of the ratio of K2SO4 to H2SO4, time, current density, and temperature on the preparation of K2S2O8 were investigated using microscale experiments and single factor experiments. The results showed that the amount of drugs was reduced to at least one-fifth of the original in microscale experiments, and the microscale experiments were easily available in instruments, energy-saving and environmentally friendly with good results. The optimal conditions for preparing K2S2O8 were: 50% K2SO4 and H2SO4 ratio, and 1.0 h electrolysis time, current density 1.0 A/cm2 and electrolyte temperature -4 ℃. In optimal conditions, the yield was 20.7%, and the purity was 92.4%. After the teaching reform, students’ experimental interests and initiative have greatly increased. The concept of green chemistry is deepened, while the ability to design experiments and inquiry, and team awareness have been enhanced.
DAI Xiao-Min, FENG Ling-Zhu. Miniature Experimental Study on Electrolytic Preparation of Potassium Persulfate[J]. Chinese Journal of Chemical Education, 2021, 42(2): 41-44.