Xiaoping Lu

Study on degradation of dimethoate solution in ultrasonic airlift loop reactor

In this work, the degradation of dimethoate solution in ultrasonic airlift loop reactor (UALR) assisted with advanced oxidation processes was studied. The effects of O3 flow rate, ultrasonic intensity, pH value and reaction temperature on the degradation rate were investigated. UALR imposed a synergistic effect combining sonochemical merit with high O3 transfer rate. Under the optimal operation conditions: ultrasonic irradiation time was 4h, O3 flow rate was 0.41 m3h(-1), ultrasonic intensity was 4.64 W cm(-2), pH value was 10.0, reaction temperature was 25 degrees C, and initial concentration of dimethoate was 20 mg L(-1), degradation rate of dimethoate increased to 90.8%. The experimental results indicated that the method of UALR degradation of organic pollutants in the presence of gas could reduce reaction time and improve degradation rate. UALR was an advisable choice for treating organic waste waters and this device could be easily scale up. Thus this process has wide application prospect in industry.

Pulsed ultrasound assisted dehydration of waste oil.

A method to aid the separation of the oil phase from waste oil emulsion of refineries had been developed by using a pulsed ultrasonic irradiation technology. Compared with conventional continuous ultrasonic irradiation, it is found that pulsed ultrasonic irradiation is much better to make water drop coalescence and hence dehydration of waste oil. The effects of ultrasonic irradiation parameters on waste oil dehydration are further discussed. The orthogonal experiment is also designed to investigate the degrees of influence of ultrasonic parameters and the optimal technological conditions. Under the optimal experimental conditions, the water content of waste oil is decreased from 65% to 8%, which thereby satisfies the requirements of refineries on the water content of waste oil after treatment (<10%).