摘要
亚硝酸在冰晶中存在以下平衡:NO2-H+HONOH+H2ONO+H2O+NO+,导致冰晶中的亚硝酸以4种形式的N(Ⅲ):NO2-,HONO,H2ONO+和NO+存在.实验发现,四种N(Ⅲ)在冰晶中分数与pH值有很大关系:pH>3,主要以NO2-和HONO形式存在;pH<3,主要以HONO,H2ONO+和NO+形式存在.冰晶中的N(Ⅲ)借助以上平衡不断产生HONO并释放到大气中,导致冰晶中N(Ⅲ)不断损失.实验还发现,冰晶中N(Ⅲ)损失率随pH值的升高先升高后下降,随N(Ⅲ)初始浓度升高而升高.紫外光能使冰晶中N(Ⅲ)发生光解,但光解速率很慢,加入.OH猝灭剂也不能提高冰晶中N(Ⅲ)的光解率.
The equilibrium equation of nitrous acid in ice：NO2^-H^＋=HONO H^＋=H2ONO^＋=H2O＋NO^＋ has demonstrated that nitrous acid （HONO） was present in ice in four different N （ Ⅲ ） species： NO2^-, HONO, H2ONO^＋ and NO^＋, the mole fraction of which has a strong dependence on pH. At pH 〉3, N（Ⅲ） species＇mainly included NO2 and HONO, while N （ Ⅲ ）existed by means of HONO, H2ONO^＋ and NO^＋ at pH 〈 3. HONO released from above dissociation equilibrium contributed to the loss of N （ Ⅲ ） in ice. The experiment results also showed that the loss percentage of N （Ⅲ ） first increased then decreased with the increasing pH, and increased with the increase of initial concentration of N（ Ⅲ ） Moreover, we studied the photolysis of N （Ⅲ） in ice and found photolysis reaction took place under UV light, but the rate of photolysis appeared to be very slow. Addition of · OH scavenger did not enhance its photolysis rate in lee.
出处
《环境化学》
CAS
CSCD
北大核心
2009年第5期621-625,共5页
Environmental Chemistry
基金
国家自然科学基金(项目号20577006)资助项目
