两种声波协同臭氧、紫外清洗与降解蔬果药残的机理研究

This project focuses on the mechanism research and parameter optimization of the ultrasonic cleaning and degradation of pesticide residues in vegetables and fruits via the synergistic effect of two kinds of ultrasound, ozone and UV. First, we develope an analytical design theory on the cleaning and degradation reactor, which is aimed to establish the resonance frequency equation of cavitation enhancement effect depended on these factors. Second, based on the obtained equation, simulation design is carried out and experimental apparatus is built. The dependency relations of ultrasonic cleaning, degradation efficiency, ultrasonic transducer, liquid whistle, ozone aeration head aperture, UV, reactor's geometry parameter are investigated. The effects of sound frequency, sound power, sound intensity, ozone concentration, gas flow rates, UV power, types and the initial concentration of pesticides, treatment time, temperature on pesticide residues treatment are performed. Since the current experimental results on acoustic cavitation are difficult to repeat due to the unknown acoustic condition, we propose an intelligent three-dimensional measuring method based on time difference and image. The theoretical and experimental data on sound power, sound intensity, sound field distribution, the cavitation bubble distribution is tested to facilitate the optimizing of the cleaning and degradation design. These treatments ensure a wide application of the proposed technology.

为探明蔬果农药残留的超声清洗与废水降解机理，拟通过液哨声波、压电超声、臭氧和紫外协同作用，进行蔬果清洗与废水降解的机理和参数优化研究。首先从理论上探讨此类清洗与降解反应器的解析设计理论，建立超声与液哨、臭氧、紫外、反应器之间形成空化增强效应的共振频率方程。进而基于所得理论方程进行仿真设计、设备研制与声处理实验研究，探讨超声清洗和降解的效率与超声换能器、液哨、臭氧曝气头孔径、紫外光、反应器的几何参数的依赖关系，研究声频率、声功率、声强、臭氧浓度、气体流速、紫外光功率、农药种类和初始浓度、处理时间、温度等对蔬果农药残留处理效果的影响。针对当前因为缺少声参数的检测手段，导致声空化成果报道中声学条件交待不明、他人重复困难的研究现状，拟提出基于时差、图像、智能三维等测量方法，并检测声处理试验中的声功率、声强、声场分布、空化泡分布，提供可推广运用、指导优化设计清洗与降解的理论与实验数据。

为探明蔬果农药残留的超声清洗与废水降解机理，本课题围绕超声核心技术进行了超声协同臭氧蔬果药残清洗降解实验平台的研制,开展了蔬果清洗与农药降解实验，并进行了空化泡溃灭过程建模、声场分布、清洗效果和降解产物方面的研究：（1）对蔬果药残清洗实验用的超声电路进行了优化与设计；（2）对实际蔬果清洗时的声场进行了测量，分别研究了果蔬被中心辐射式声源和侧壁式声源辐照时的声强分布测量图像；（3）开展了超声协同臭氧降解有机磷农药乙酰甲胺磷的实验研究，分析结果表明，乙酰甲胺磷经处理后被分解生成NH4+、NO3-、SO42-、 CO2、 H3PO4等易溶解于水的低毒或无毒产物；（4）进行了表面含毒死蜱蔬菜的农药清洗与降解实验，研究了超声频率与降解率之间的关系，通过质谱图分析得出，降解后生成的产物为低毒的TCP(3,5,6-三氯-2-羟基吡啶)。本课题的研究，为基于功率超声的蔬果药残清洗技术研究奠定了一定的实验基础，通过联合企业开展设备研制，促进了这一极具发展前景的新型清洗技术走向实际生产应用。