Retention and Transport of Bisphenol A and Bisphenol S in Saturated Limestone Porous Media

The release of bisphenols such as bisphenol A (BPA) and its alternative bisphenol S (BPS) into the subsurface environment may cause serious pollutions to soil and groundwater. However, only few works have examined their fate and transport in porous media. In this work, batch and column experiments and mathematical modeling were conducted to study the transport behaviors of BPA and BPS in water-saturated limestone porous media. The effects of contaminant input concentration, solution ion type, and solution ionic strength on the retention and transport of BPA and BPS in the columns were investigated. BPS had higher mobility in limestone porous media than that of BPA. With its input concentration decreased, BPA showed lower mobility, while the transport of BPS in the media was not affected by the input concentration perturbations. The retention of both BPA and BPS was higher in divalent calcium ion solution than that in monovalent sodium solution in limestone porous media. Ionic strength showed little effect on the retention and transport of BPA and BPS except that high concentration of Ca2+ inhibited the migration of BPS in the media. Because of its relatively high mobility and toxicity, BPS may present a great risk to groundwater quality and thus may not be an environmentally friendly bisphenol alternative.