海带浸泡液中碘离子的新型氧化工艺的研究

Study on new oxidation process for iodine ion in kelp soaking liquid

采用亚硝酸钠-过氧化氢混合氧化剂将海带浸泡液中的碘离子氧化为碘酸根离子,并以其为氧化剂进一步氧化海带浸泡液中的碘离子生成单质碘,达到回收碘的目的。研究了利用混合氧化剂制备碘酸根离子的反应条件,得到最佳反应条件为:100 mL的含碘量为498 mg/kg的海带浸泡液需要加入混合氧化剂的量分别为50μL 8%(质量分数)亚硝酸钠溶液、150μL 30%(质量分数)过氧化氢(过氧化氢与碘离子物质的量比为3.5∶1)。将制得的碘酸根离子作为氧化剂氧化碘离子,考察了pH、碘离子与碘酸根离子物质的量比、反应时间对海带浸泡液中碘离子氧化率的影响。结果表明,在pH为2.0、碘离子与碘酸根离子物质的量比为5∶1、反应时间为30 min的最优条件下,碘的氧化率为94.96%。

I- in the kelp soaking liquid was oxidized into IO3- by the mixed oxidant NaNO2-H2O2, and with the oxidant IO3-, I- in the soaking liquid was further oxidized into elemental iodine ,to achieve the purpose of recycling iodine. The reaction conditions of using mixed oxidant to prepare IO3- were studied.The optimum reaction conditions were as follows： the dosage of mixed oxidant was 50 μL, 8% （mass fraction） NaNO2 solution and 150 μL, 30% （mass fraction） H2O2 （the amount-of-substance ratio of H2O2 to I- is approximately 3.5：1）,in 100 mL of kelp soaking liquid with the iodine content of 498 mg/kg.The obtained IO3- was as the oxidant to oxidize I-.The effects of pH, amount-of-substance ratio of I- to IO3- and reaction time on I- conversation rate were investigated.Results showed that when the pH was 2.0, the amount-of-substance ratio of I- to IO3- was 5：1, and the reaction time was for 30 min, the iodine oxidation rate was 94.96%.