New developed framework for breakthrough curve prediction at typical indoor levels of concentration and relative humidity

Adsorption-based granular activated carbon (GAC) filters are commonly used to purify indoor air by removing indoor air pollutants. The pollutants' concentrations that typically encounter in indoor environment are very low thus increases the role of humidity on the filter performance. The existing standard recommends the tests to be carried out at 100 ppm (accelerated tests), which is much higher than the actual contaminant concentrations in buildings. Therefore, there is a need to develop a framework to evaluate the performance of these technologies at low concentration. The method is based on the application of a set of isotherm and breakthrough models as a tool for extracting the data from higher concentrations and translating them into the low level concentrations. Results show that stoichiometric breakthrough times, the adsorption rate constants (in Wheeler-Jonas equation) and product constants (in Yoon-Nelson equation) are not strongly dependent on concentration, demonstrating some indicators for simulating the experiments at indoor air level conditions. Also, the overall mass transfer coefficient in the Wheeler-Jonas equation and the proportionality constant in the Yoon-Nelson equation (both as a function of adsorption capacity) are a function of humidity level