Ethylenediamine-modified activated carbon photocatalyst with the highest TiO2 attachment/dispersion for improved photodegradation of sulfamethazine

Due to the high pollution caused by several molecules, it is necessary to develop efficient materials to degrade these contaminants. Activated carbons (ACs) are exceptional and versatile adsorbents, and titanium dioxide (TiO2) has remarkable photocatalytic properties. The combination of activated carbon (AC) and TiO2 provides a system capable of simultaneously adsorbing and degrading several emerging contaminants. This study presents a new absorbent/photocatalyst material by modifying the AC with ethylenediamine (ET) and impregnated with TiO2 (AC-ET/TiO2). AC modified with amine groups keeps the TiO2 nanoparticles more bound onto its surface. A study exploring the dispersion onto the surface of unmodified AC revealed that the material lacked stability, releasing TiO2 particles into the solution. The characterization by nitrogen adsorption/desorption isotherms showed a mesoporous material that can have a synergic effect between the adsorption and photocatalysis. The photocatalyst was analyzed by field emission gun scanning electron microscopy (FEG-SEM) and demonstrated the presence of TiO2 dispersed on the surface. The AC-ET/TiO2 exhibited an improved photodegradation of sulfamethazine (SMT), superior to the commercial TiO2 – P25, by removing more than 90% of the SMT in 2 h of UV light irradiation. The reuse of the AC-ET/90TiO2 showed that this material is active after three photoreactions. In conclusion, amino groups insertion into AC is essential for the stability of the TiO2 on the surface. Besides, this material has increased photocatalytic activity with speedy degradation of SMT.