Adsorption behavior and mechanism of sulfonamides on phosphonic chelating cellulose under different pH effects.

• PCCSF was synthesized successfully through the chelating modification. • PCCSF exhibited excellent adsorption capacities of SD, SMM and SMZ. • Adsorption behavior and mechanisms depended on various pH values. • Electrostatic repulsion and hydrophobic interactions decreased adsorption capacity. • Lewis acid-base interaction, EDA and CAHB were favor for adsorption. Phosphonic chelating fiber (PCCSF) as a novel adsorbent was produced through alkalization, etherification, amination and phosphonation, and then it was applied to adsorb sulfonamides (SAs), such as sulfadiazine (SD), sulfamonomethoxine (SMM) and sulfamethoxazole (SMZ). Specially, their adsorption behavior at different pH values was studied. As a result, PCCSF was provided with amino (NH 2 or NH) and PO(OH) 2 (P O) groups, and its equilibrium data were generally represented by both Langmuir and Freundlich models. Combining adsorbent-to-solution distribution coefficients (K d) values and the effect of pH, the primary mechanism suggested that adsorption capacity of PCCSF was lower in strong acid and alkali solution, due to the electrostatic repulsion and hydrophobic interactions. By contrast, its adsorption affinity became more excellent at 3 < pH < 9 owing to the π-π electron-donor-acceptor (EDA) charge-assisted H-bond, Lewis acid-base interaction and charge-assisted H-bond (CAHB). [ABSTRACT FROM AUTHOR]