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^-1 in the range of 150 to 180 g·L^-1,the reaction rate constant of gelatin degradation enlarged by 1.2 times. 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% to 90%.