Application And Mechanism Of Microwave Remediation Of Volatile Organic Compounds Contaminated Soil

Soil is one of the important resources for human survival.In recent years,with the implementation of the Stockholm Convention and the adjustment of the structure of chemical companies,a large number of heavily polluting chemical companies have successively relocated and closed down to form many polluted organic contaminated sites in China.However,the development of soil remediation technologies,engineering applications,and equipment for organic-contaminated sites in China started late.At present,China's soil remediation technology has the problems of single technology types,severe lack of technical equipment,lack of industries,lack of technical specifications,lack of engineering restoration cases,lack of innovative enterprises,and low investment.In this experiment,the soil contaminated with toluene was repaired by microwave desorption technique.The effects of pollutant concentration,soil moisture content,soil thickness and microwave power on the removal rate were investigated.Orthogonal experiments and kinetic experiments were carried out on the technology of microwave desorption of volatile organic compounds in soil.The experimental results are as follows:1)In the laboratory repair process,the pollutant content is 10g·kg^-1,the water content is 15%,the soil layer thickness is 0.5cm,and the pollutant removal rate reaches 100%when the power is 1500W for 20min.2)An orthogonal experiment of four factors and three levels is designed.The optimal level combination is:time 30min,moisture content 25%,power 1000W,soil layer thickness 0.5cm,pseudo-second-level reaction kinetic equation can better describe microwave desorption The reaction process of toluene in soil,and the control process of toluene desorption from soil is mainly inter-particle diffusion.3)The engineering repair experiment shows that the water content is an important factor affecting the soil desorption of organic matter by microwave desorption.It is a microwave radiation desorption-decomposition technology system,including microwave soil desorption equipment,organic gas microwave decomposition equipment and microwave irradiation desorption-decomposition.Provide data support by running process parameters and the like.4)In the engineering application,the exhaust gas adopts a microwave catalytic combustion device,and its purification efficiency reaches 93%.