Sonochemical degradation of organophosphorus pesticide in dilute aqueous solutions
超声波降解在农药水溶液的有机磷
Robina farooq , lin feng kai , S.F.shaukat , HUANG jian jun Abstract :ultrasonic irradiation was found to accelerate the rate of omethoate in aqueous solution over the pH range of 2-12 process parameters studied include pH, steady-state temperature, concentration, and the type of gases.
超声波照射发现，加快了工艺参数的pH值2-12范围内的氧乐果率在水溶液中，研究包括pH值，稳态温度，浓度和气体的类型。
Greater than 96%hydrolysis was observed in 30 minutes through this process and the rate of destruction o,，and the rate of destruction increas ed with the help of more soluble and low thermal inert gas .So with Krypton, omethoat was found to undergo rapid destruction as compared with Argon．
大于96％，水解，观察在30分钟内通过这一进程，并销毁率，以及提高与破坏与更多的可溶性和低的热惰性气体帮助编率。与氪因此，氧化乐果，发现接受迅速销毁氩比较。
In the presence of ultrasound．the observed first一0rder rate of hydrolysis of omethoate is found to be independent of pH．
在超声普雷塞罗富国教育学院，所观察到的第一个一氧化乐果水解0rder率被发现是独立的pH值The formation of transient super critical water(SCW)appears to be an important factor in the acceleration of chemical reactions in the presence of ultrasound．超临界水的瞬间（SCW）的王蕊，ARS的形成是一个
都是最重要的化学反应研究加速度吨因子在超声波的存在。
Keyword：sonochemical degradation声化学降解。；omethoate pesticide 氧化乐果农药;sonolysis超声降解符合；role of inert gases惰性气体的作用
1 Experimental实验
Ultrasonic irradiation of aqueous solutions of omethoate，the organophosphorous pesticides were carried out with a vibra cell model VC-250 direct immersion ultrasonic horn(sonics and materials)operated at the frequency of 20kHz with a constant power density of 50W／cm2．超声波对氧化乐果水溶液照射下，有机磷农药进行了一个弯扭耦合振动的细胞模型的VC - 250直接浸泡变幅杆（超音速队和材料）在20kHz的具有恒功率密度的50W/cm2频率操作。Reactions were conducted in a glass sonication cel1．The horn titani um tip was immersed about 3cm into the solution．反应是在一个玻璃超声波细胞进行，喇叭铁但这个尖端浸泡约3公分到该解决方案。The bottom of the glass reactor
had a 1cm indentation in the center for reflection of sound waves and for even distribution of cavitation bubbles in the solution．在玻璃反应器底部有一对声波反射中心1cm的缩进和空化气泡甚至分布在溶液中。The reaction volume was 100m1．The upper part of the cell is modified by the addition of gas dispersion and sampling tubes．反应体积为100毫升，单元格的上半部分是由气体扩散和取样管除了修改。
2 Analytical methods分析方法
Different parameters in liquid were determined according to standard methods(1992Peter,1992)：(1)total phosphorus(TP)was determined by persulphate digestion method followed by ascorbic acid method；(2) inorganic phosphorus(OP) was determined by ascorbic acid(molybdenum blue)method and(3)organic phosphorus(OP) was calculated by: OP=TP—IP．液体在不同的参数，确定根据（，1992年的标准方法；彼得，1992年）：（1）总磷（TP）的测定方法过硫
酸盐消化其次抗坏血酸酸法（2）无机磷（IP）的测定抗坏血酸（钼蓝）方法
（3）有机磷（OP）的计算方式: OP=TP—IP
3 Results and discussion结果与讨论
Exposure of omethoate solutions in the presence of dissolved gas Kr results in a decrease of the [omethoate] in the solutions曝光中溶解气体氪结果存在，一对[在溶液氧化乐果]减少氧化乐果的解决方案。．Fig．1shows the plot of[omethoate]versus sonication time at two initial [omethoate]，greater than 96％removal efficiency is observed in the current experiment．显示[氧化乐果]阴谋与超声时间在两个初始[氧化乐果]，大于96％的去除率实验观察到武珊妹Initial [omethoate] as high as 200mg／L and 50mg／L dropped to about 6.2 mg ／L and 0.4mg／L respectively after 30 minutes of irradiation．初步[氧化乐果]如为200mg / L和50mg / L的下降/ L和0.4mg / L的分别照射后30分钟，高约6.2毫克。This enhanced rate of hydrolysis is considered due to two reasons．is that during sonolysis，within the collapsing cavitation bubbles，the conditions of temperature and pressure exceeding the critical point of water．So there is supercritical water around the collapsing cavitation bubbles．Hydrolysis is accelerated in part，by a higher concentration of 0H at the hot bubbles interface, which result from the high ion product of water．这种增强的水解率被认为是基于两个原因。在超声降解符合，在倒塌的空化气泡，温度和压力超过了水的临界点的条件。
4 Mechanism and model development机理和模型开发Considering the major plausible elementary reactions of water and organics．考虑到主要的水和有机物可能的基本反应。The reactions are initiated by the dissociation of water molecules in the collapsing cavitation
holes．Atomic hydrogen(H。) and hydroxyl (。OH) are formed through this reaction．的反应都是由水分子离解在倒塌的汽蚀孔。原子氢（H。）和羟基（。俄亥俄州）是通过这种反应形成的。These two radicals recombine to form water or hydrogen molecules(H2)，or they react with oxygen molecules(O2) to yield hydroperoxide (HO2) or hydrogen peroxide(H202;Eqs．(2—6))．These radicals further react with the H2O2produced in these reactions to form hydrogen molecules(H2)，water or other radicals(Eqs．(7—10))．这两个自由基重组形成水或氢分子（H2）的，或者他们与氧分子（O2的反应）产生过氧化物（过氧）或过氧化氢。这些自由基进一步与这些反应产生的氢分子组成（氢的过氧化氢反应），水或其他激进分子.
5 Conclusions结论
Ultrasonic irradiation process is a promising and effective process for the destruction of omethoate in water．超声辐照过程是一个在水中的氧乐果销毁前景和有效的过程。More than 98％rate of hydrolysis is achieved through this process．超过98％的水解率是通过这一进程。The major reactions are the destruction inside the cavitation bubbles because the rate of reaction increases by subjecting more soluble and low thermal conductive gas that results the increase of temperature inside the collapsing bubble．主要的反应是空化气泡内部的破坏，因为遭受更多的可溶性和低导热气体，结果泡沫崩溃内的温度升高，反应速率增加。The rate of hydrolysis is almost unaffected by increasing the temperature of reactor 翻译
the bulk liquid．该水解率几乎增加了散装液体温度不受影响。This shows that a few secondary reactions of omethoate take place in the
solution．这表明，氧化乐果采取的解决方案中的二次反应发生数Decreasing the concentration increases the rate of hydrolysis，so this ultrasonic irradiation is a valuable tool to hydrolyze those solutions，which contain low concentration of organics．降低浓度增加，水解率，所以这是一个有价值的超声波照射水解这些解决方案的工具，它包含的有机物浓度低pH value of the irradiation solution is found to have a little effect upon the omethoate destruction．在照射溶液的pH值被发现后，氧化乐果销毁的影响不大。This is an advantage over other methods where the adjustment of pH is a problem，so solution having any pH can result efficient hydrolysis．这是一个优势在那里的pH值调整是一个问题的其他方法，使溶液pH值的结果有任何有效的水解。

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