Valorization of Drinking Water Treatment Residuals to High-Performance Adsorbents

Abstract

This thesis develops a circular valorization pathway that converts drinking water treatment residuals (WTR) into high-performance adsorbents and evaluates performance, regeneration, and system feasibility. WTR was transformed into porous materials via ZnCl₂-assisted thermal activation, with synthesis optimized to enhance porosity while retaining reactive surface sites. The adsorbents were tested for aquaculture antibiotics and representative anionic and cationic dyes, with adsorption interpreted using kinetic, equilibrium, and thermodynamic analyses to identify contaminant-dependent mechanisms. To assess practical applicability, pelletized materials were evaluated in continuous fixed-bed systems, where breakthrough behavior was described using column models and linked to operating conditions. Regeneration using chemical and electrochemical methods demonstrated partial capacity recovery over multiple cycles. Techno-economic analysis identified thermal energy and chemical use as key cost drivers, while life cycle assessment showed that optimized valorization can reduce environmental burdens relative to landfilling. Overall, this work establishes an integrated framework for scalable circular deployment of WTR-derived adsorbents.