The Importance of Humic Substances in Transporting “Chemicals of Emerging Concern” in Water and Sewage Environments

Abstract

In this study, we examined the sorption of selected “chemicals of emerging concern” (CEC) on humic substances commonly found in water and municipal wastewater. These were ibuprofen, diclofenac, caffeine, carbamazepine, estrone, triclosan, bisphenol A, and isoproturon. The humic substances (HSs) were synthetic and not contaminated by the tested organic substances. The elemental composition and content of mineral micropollutants, gravimetric curves, and the IR spectrum of HSs were determined. We determined a relationship between the process efficiency and the characteristics of a sorbent and sorbate using the properties of organic substances sorbed on HSs. This relationship was confirmed by sorption tests on the HS complex, i.e., the HS-organic micropollutant. It has been shown that the given complexes have a greater affinity for hydrophobic surfaces than hydrophilic surfaces. To confirm the nature of the sorbent surfaces, we determined their zeta potential dependence on the pH of the solution. Studies have shown that HSs are carriers of both mineral substances and CEC in water and sewage environments.