The thermal desorption is on the basis of pollutant’s volatility and heat the contaminated soil using
steam, microwave, infrared radiation to make the pollutant (e.g. Hg, As) volatile. The volatile heavy
metals are then collected using the vacuum negative pressure or carrier gas and achieve the aim of
removing the heavy metals [9]. According to the temperatures, the traditional thermal desorption can be
classified into high temperature desorption (320~560°C) and low temperature desorption (90~320°C).
This technology has advantages of simple process, devices with mobility and the remediated soil being
reused. A company of mercury collection and service in USA has used this technology for in-situ
remediation and developed commercial service. However, the limited factors, such as the expensive
devices, long desorption time, limit its application in the soil remediation [10].