© 2020, Springer Nature Singapore Pte Ltd. PM2.5 can be purified by porous materials beds by the effect of van der Waals force and electrostatic force, but the materials become saturated when the pores in beds are filled. In that case, they lose the ability of cleaning. In relevant references, some methods are proved they can bring out the particles inside the pores including back blowing, heating and immersing the materials in liquid. In this chapter, an experiment system is made to find out the desorption regularity of these methods. At first, the materials in the column catch PM2.5, then desorption process (blowing, heating or immersing alone) begins, during which the pressure drop decreases from the maximum to residual pressure drop and this value reflects the extent of desorption. Results of experiments show that both methods are available. Back blowing and heating can reduce pressure drop of the column and the residual drop becomes lower when air quantity or heating temperature increases until a critical air quantity or temperature is arrived. For immersion, the results show acid liquid has a higher efficiency. According to these conclusions, the recycle of materials becomes realizable, and filters can be more economical.