【摘要】 研究了清洁高效的氧化剂H2O2对海藻酸钠的降解,探讨了溶液pH值、反应温度、H2O2用量及金属离子浓度对降解速度的影响。结果表明,随着溶液pH值的降低、反应温度的升高及H2O2用量的增加,降解速度加快。当反应pH=5.3、反应温度50℃、H2O2用量0.5%时,反应2 h即可降低海藻酸钠的分子量。4 mg/L的Cu2+或Fe2+可明显加快降解速度,反应30 min的粘度变化相当于不加Cu2+或Fe2+时300 min的变化。GPC结果表明,海藻酸钠被氧化降解后,分子量下降,分布变宽;FTIR显示降解前后海藻酸钠的糖环结构没有改变,主要是糖苷键的断裂。更多还原

【Abstract】 The clean and effective oxidant,hydrogen peroxide,was used to degrade alginate in order to prepare its low molecular products,and the effects of pH,temperature,amount of H2O2 and metal ions on the degradation were investigated.The degradation rate increased with the decrease of solution pH,and the increases of reaction temperature and oxidant dosage.Low molecular alginate could be obtained effectively with pH of 5.3,temperature of 50 ℃ and H2O2 of 0.5% for 2 h reaction.The reaction could be also significantly accelerated by 4 mg/L Cu2+ or Fe2+.GPC analysis showed that the average molecular mass of alginate was decreased and the molecular mass distribution was broadened.It can be inferred from FTIR that the degradation was caused by OH radicals produced by hydrogen peroxide,which resulted in the breakage of the glycosidic C(1)—O—C(4) bond.更多还原