Cosorption of organic chemicals with different properties: Their shared and different sorption sites

Abstract

Complementary sorption of different chemicals was expected and investigating the relationship between the sorption inhibition of primary sorbate (Δ Q pri) and sorption of secondary sorbate ( Q sec) could provide a new angle to understand coadsorption of different chemicals. This study used bisphenol A (BPA) as the primary adsorbate, sulfamethoxazole (SMX) as the competitor, and carbon nanotubes as model adsorbents to study their complementary and competitive adsorption. At low BPA concentrations, the sorption of SMX ( Q sec) exceeded BPA sorption inhibition (Δ Q pri), indicating that these two chemicals complementarily adsorbed on their respectively preferred sorption sites. At high BPA concentrations, higher Δ Q pri was observed in comparison to Q sec, which may be resulted from different packing efficiencies of the adsorbed SMX and BPA. This study emphasized that both competitive and complementary sorption should be discussed in binary sorption system.