离子交换树脂法高效提取水中硝酸盐研究

硝酸盐是水体中重要的污染物之一,硝酸盐中的稳定氮氧同位素组成可用于有效识别其污染来源,而水体中硝酸盐的高效提取是其氮氧同位素测试的前提和关键步骤。阴离子树脂交换法提取硝酸盐是目前普遍采用的方法,但对于提取效率的影响因素还缺乏深入研究。文章通过室内实验,探讨了国产717型阴离子树脂对硝酸盐的吸附效率,以及不同洗脱剂的洗脱效率,系统研究了水体中硝酸盐高效提取过程影响因素。结果表明:12.56 mL体积的国产717型树脂对NO3-的吸附量高达200 mg以上;40 mL 4 mol/L的KCl溶液对4 cm长的吸附树脂柱(直径2 cm)的洗脱效率可达95%以上;SO42-的对NO3-的吸附和洗脱具有显著的影响。

Study of Effectively Extracting Nitrate by Anion Exchange Column

Nitrate is one of the important sources of pollution in the water.Nitrogen and oxygen isotope ratios of nitrate provide a powerful tool to investigate nitrate sources.However,the δ15N and δ18O analysis is based on concentrating nitrate from fresh waters.Every step for collection and preparation of nitrate would affect the concentration efficiency.Anion exchange column technique is the most widespread use,but the influence factors of extract nitrate is still need to be further research.The results indicated that the sorption efficiency of domestic 717 anion exchanging resin(12.56 mL) was higher than 99.9% for solutions with nitrate capacity of 200 mg.During the removal of dissolved organic carbon,the activated carbon would absorb the nitrate,and when the concentration was lower,the absorb ration was higher.The elution recovery was higher than 95% when resin column was 4 cm in length and eluted by 40 mL 4 mol/L KCl solution.A significantly decrease of nitrate adsorption efficiency and elution recovery can be caused by the sulfate.