硫氰根的γ射线辐照降解研究

Radiolysis of Aqueous Solution of Thiocyanate by γ-Rays

研究了60Co源γ射线辐照降解SCN-.在溶液pH=1、pH=3时,25 mg/L的SCN-在6 kGy下基本能够得到降解,降解率分别达到98.11%、95.97%,pH=7时,在9 kGy下,SCN-的降解率为99.33%;但在碱性条件下,18 kGy的剂量下,才能得到降解,达99.64%(pH=10)和99.93%(pH=12).在高浓度下,SCN-溶液的降解则需要更大的剂量.通过对辐照后的SCN-溶液TOC和TN的测定可知:辐照法对SCN-溶液除去TOC和TN效果不明显,不同剂量辐照后溶液中SO42-和NO3-浓度的变化表明,SCN-在γ射线辐照过程中可能的反应历程为:硫元素首先被除去,转变成SO42-,而氮元素则很少转变成NO3-,主要是以其它形式的氮存在.

Radiolysis of aqueous solution of thiocyanate by^60Co γrays was studied.In condition of pH=1 and pH=3,25mg/L SCN^-was decomposed under the dose of 6 kGy,with decomposition rate of 98.11%（pH=1） and 95.97%（pH=3） respectively.25（mg/L） SCN^-（pH=7） was decomposed under the dose of 9 kGy and the decomposition rate is 99.33%.In the alkaline condition,pH=10 and pH=12,the dose of 18 kGy was need,and the decomposition rate is 99.64%and 99.93% respectively.High SCN^-concentration means that more radiation dose is need.From the comparison of before radiolysis and after radiolysis＇s TOC（total organic carbon） and TN（total nitrogen） of SCN^-solution,little TOC and TN was removed.The determination of SO4^2- and NO3^- concentration indicated that sulfur element was removed and converted to SO4^2-,and nitrogen element rarely converted to NO3^-,but converted to other forms of nitrogen.