This study investigates continuous fixed-bed adsorption and catalytic ozonation for the removal of diclofenac sodium from aqueous media using green-synthesized multi-walled carbon nanotubes (green-MWCNTs) as multifunctional adsorbent–catalyst materials. The environmentally friendly synthesized MWCNTs provide active adsorption sites through π–π interactions, structural defects, and oxygen-containing functional groups, enabling adsorption and catalytic activity. Fixed-bed columns composed of green-MWCNTs combined with glass microspheres and colloidal amorphous silica were applied to improve nanotube dispersion, hydraulic stability, and accessibility of active sites during continuous operation. Material characterization confirmed preservation of nanotube structure and successful incorporation into the surface of microspheres. Breakthrough curves were well described by the Dual Site Diffusion model, indicating the presence of heterogeneous adsorption sites. Beyond adsorption, green-MWCNTs promoted ozone decomposition and formation of reactive oxidative species, enhancing diclofenac degradation during catalytic ozonation. Under optimized conditions (O 3 concentration = 30 μg mL⁻¹, reaction time = 30 min, catalyst dosage = 2 g L⁻¹), a maximum degradation efficiency of 76% was achieved for an initial concentration of 0.2 mmol L⁻¹. These results demonstrate the effectiveness of green-MWCNTs as scalable multifunctional material for both adsorption and advanced oxidation processes for water treatment applications.
Spaolonzi et al. (2026) studied this question.