Three-Dimensional-Alumina-Supported Activated Carbon for Water Treatment and In Situ Regeneration Through Catalytic Wet Peroxide Oxidation

Conventional wastewater treatment processes are often ineffective at removing micropollutants, which pose risks to aquatic ecosystems and human health. To address this, a novel method was developed to immobilise activated carbon (AC) onto three-dimensional alumina spheres, enabling easier operation and regeneration while enhancing sustainability and efficiency in treating organic micropollutants.

The immobilisation process involved thermal decomposition of commercial AC (AC_com) with urea in water. Pristine AC_com and urea were also treated similarly for comparison. The adsorption performance was evaluated in batch and continuous flow systems using venlafaxine (VFX) as a model contaminant. Regeneration was studied via catalytic wet peroxide oxidation (CWPO), using hydrogen peroxide (H₂O₂) to restore adsorbent functionality.

Batch experiments showed that AC_com removed >99% of VFX, while AC/U₅₀ achieved 67.1% removal in 60 minutes. Immobilisation onto alumina spheres was only successful via thermal treatment with urea, forming S-AC/U₅₀. In a continuous flow, S-AC/U₅₀ removed 70% of the VFX in 60 minutes, with saturation after five days.

Introducing H₂O₂ activated CWPO, boosting the VFX removal to 99% and maintaining >97% efficiency over five days, preventing adsorbent saturation. The H₂O₂ consumption ranged from 9% to 45%, confirming catalytic activity and regeneration potential.

In summary, AC was successfully immobilised onto alumina spheres via thermal treatment with urea. The resulting S-AC/U₅₀ material demonstrated a high adsorption and regeneration performance, especially under CWPO conditions, offering a promising strategy for sustainable micropollutant removal in water treatment systems.