硫酸根自由基(SO₄^－ · )是选择性小、氧化还原电位高的自由基，和羟基自由基(OH· )一样能够被运用于难降解有机污染物的去除．文中对热激活过硫酸钠产生 SO₄^－ · 降解典型农药敌草隆进行了研究，通过实验考察了反应温度、敌草隆浓度、过硫酸钠投加量、初始pH 值以及地下水中几种典型阴离子(CO₃^2－、HCO₃^－ 和Cl^－)对降解效果的影响．结果表明:热激活过硫酸盐对敌草隆的降解符合准一级动力学模型(r² ＞0．95)， 且温度对敌草隆降解速率的影响符合阿伦尼乌斯模型(r² ＞0．95);当温度在 50 ～70 ℃时，产生的活化能为(166．7 ±0．8)kJ/mol;准一级反应速率随过硫酸盐投量增加而增大， 随初始底物浓度增大而减小;最大反应速率发生在 pH 值为 6．3 时(准一级反应速率常数 k_obs =0．003min－1 );地下水中3 种典型阴离子对降解过程的抑制程度为 CO₃^2－＞HCO₃^－＞Cl^－．由此可见，热激活过硫酸盐氧化法可作为降解敌草隆和其他地下水中关注较多的有机污染物的一种有效途径．

Sulfate radical (SO₄^－ · )，a kind of radical with low selectivity and high oxidation reduction potential,can be applied to the removal of nondegradable organics,just like hydroxyl radical (OH·).In this paper,the deg-radation of a typical pesticide diuron by the sulfate radical produced by heat- activated persulfate was investigated,and the effects of temperature,diuron concentration,sodium persulfate dosage,initial pH value and some commonanions (CO₃^2－,HCO₃^－ and Cl^－) in groundwater on diuron degradation were analyzed by experiments.The resultsshow that (1) the degradation of duiron by heat- activated persulfate follows a pseudo first- order kinetic model (r² ＞0.95); (2) the effect of temperature on duiron degradation rate well accords with the Arrhenius model (r²＞0. 95); (3) the apparent activation energy achieves (166.7 ±0.8)kJ/mol when the temperature ranges from 50 to70℃; (4) the pseudo first- order degradation rate increases with the increase of persulfate dosage but with the decreaseof the initial diuron concentration; (5) the observed rate constant achieves the maximum (k_obs =0.003min－1 ) atpH 6/3; and (6) the degradation inhibition by anions follows the order of CO₃^2－＞HCO₃^－＞Cl^－.It is thus concludedthat the heat- activated persulfate oxidation is suitable for the degradation of organic pollutants such as diuron ingroundwater.