Performance evaluation of particulate matter removal by surfactant foams

Abstract

Surfactant foams can be repeatedly formed and ruptured, providing an extensive surface area which can be utilized for the contaminant removal. In order to mitigate the expenses associated with filter maintenance in the filter-equipped device, the particulate matter removal was attempted by the surfactant foam in this study, aiming to assess the feasibility as an alternative technology for improving air quality. Two types of particulate matter (Arizona test dust (ATD) and incense stick) and two types of surfactants (SLS-30 and LAO) were adopted to evaluate the removal efficiency of particulate matter under different surfactant concentrations (0.05, 0.1, and 0.2 wt%) and different flow systems (with and without internal airflow). Overall, ATD were better removed than incense stick due to the larger size which resulted in the greater sedimentation and subsequent contact with foams. Also, SLS-30 showed better removal performance than LAO as the surfactant concentration increased from 0.05 wt% to 0.2 wt%. These findings can be attributed to foam generation properties, in which SLS-30 demonstrated superior foam generation capabilities as the surfactant concentration increased, providing a larger surface area for PM adsorption as well as suppressing the remaining headspace in the chamber. The findings in this study presents the advantageous utilization of foams as an adsorbent for PM as well as a filling material in the limited space, thereby enabling enhanced PM removal capabilities.