Influence of Sulfuric Acid Concentration and Temperature on Gelatin Degradation in Copper Electrolytes

Dialysis was utilized to separate gelatin whose relative molecular mass is over 3500 from a simulated copper electrolyte,and the concentration of separated gelatin was determined with a bicinchoninic acid( BCA) method. The impact of H2SO4 concentration and temperature on gelatin degradation was investigated. It was found that Cu2 +hardly affected the stability of gelatin. Increases in electrolyte temperature and H2SO4 concentration exacerbated gelatin degradation. For constant temperature,when the H2SO4 concentration increased by 15 g·L-1in the range of 150 to 180 g·L-1,the reaction rate constant of gelatin degradation enlarged by 1. 2times. For constant H2SO4 concentration,raising the temperature by 5 ℃ in the range of 55 to 70 ℃ increased the reaction rate constant of gelatin degradation by 1. 5 times. For copper electrolysis production,when the concentration of H2SO4 in the copper electrolyte was 150 to 180 g·L-1and the temperature was 60 to 65 ℃,it could be estimated that the residence time of the electrolyte in the electrolytic cell was 3 to 4 h and the gelatin degradation rate in the electrolyte reached to 50% to 80%. A complete cycle of the electrolyte in the copper electrolysis system took about 6 h,and at this moment the gelatin degradation rate in the electrolyte reached to 70% to90%.