Contaminants of emerging concern (CECs) adsorption on superfine activated carbon

Contaminants of emerging concern (CECs) adsorption on superfine powdered activated carbon (S-PAC) (0.6 μm mean size) at conventional water treatment plants (WTP), where feasible contact time is usually shorter than 2 hours, was analyzed. Laboratory-scale experiments were carried out having deionized water (DW) and raw water (RW) samples fortified for atrazine (ATZ), 17β-estradiol (E2), and 17α-ethinylestradiol (EE2). Adsorption diminished due to natural organic matter, but in a smaller extension for S-PAC. Multi-solute removal efficiencies kept the same ranking for DW and RW, i.e., E2 > EE2 > ATZ, following compounds' hydrophobicity and molecular size. Hydrophobic and H-bonding interactions were the main adsorption mechanisms. For all target compounds the adsorption process was controlled by film diffusion. S-PAC presented higher adsorption as well as lower desorption as compared to powdered activated carbon, achieving similar efficiencies for half dosage and same contact time or at half contact time and same dosage. Physicochemical processes at WTP are capable to remove contaminated S-PAC particles.