热化学法降解农药废盐中的有机物

Degradation of organics in pesticide waste salts by thermochemical method

利用热重/微分热重确定热化学法降解农药废盐中有机物的温度范围。以总有机碳(TOC)为评价指标,通过正交、单因素实验考察了在空气、氮气及氧气气氛中,温度、停留时间、升温速率、气体流速对TOC去除率的影响。利用傅立叶变换红外光谱、气相色谱—质谱、X射线衍射和扫描电子显微镜分析了热化学处理前后有机物和无机物的变化情况。结果表明:热化学法降解农药废盐中有机物的适宜温度为300~900℃。各因素的影响程度表现为温度>停留时间>升温速率>气体流速,最佳处理条件为空气气氛、温度900℃、停留时间45 min、升温速率20℃/min、气体流速200 mL/min,此条件下TOC去除率达到99.51%。处理后农药废盐有机物含量大量减少,无机物晶体结构不变。

Thermogravimetric/differential thermogravimetric analysis was used to investigate the temperature range for the thermochemical degradation of organic compounds in pesticide waste salts with total organic carbon(TOC)as an evaluation indicator.Influences of temperature,residence time,heating rate and gas flow rate on removal efficiency of TOC in different atmosphere like air,nitrogen and oxygen were investigated through orthogonal and single-factor experiments.The composition changes of organic and inorganic compounds before and after the thermochemical treatment were also analyzed by Fourier transform infrared spectrometer,gas chromatography-mass spectrometry,X-ray diffraction and scanning electron microscope.Results showed that the best temperature range for thermochemical treatment of pesticide waste salts was 300-900℃.And the optimum treatment conditions were as follows:air atmosphere,temperature 900℃,residence time 45 min,heating rate 20℃/min and gas flow rate 200 mL/min,the TOC removal rate reached 99.51%under those conditions.After treatment,organic compounds in the pesticide waste salts were greatly reduced and the crystal structure of inorganic compound remained unchanged.