An analytical solution for VOCs sorption on dry building materials

Based on the diffusion within the material and the mass transfer through the air boundary layer, a VOCs sorption model with an arbitrary inlet concentration is proposed. With the use of Laplace transform and convolution theorem, a method to get the analytical solution has been developed, which helps to understand the mechanism of the sorption theoretically and makes the computation convenient. Experimental results on VOCs sorption in an environmental chamber are used to validate the present model and a good agreement has been obtained. Two cases of different inlet concentrations are discussed in detail. The patterns of the concentration distribution in the air vary with the inlet concentration. The influences of model parameters have been investigated. With the increase of the diffusion coefficient and the partition coefficient, the rate of the adsorption increases. Relatively, the partition coefficient plays a more important role in the sorption than the diffusion coefficient.