Solar Light-Induced Methylene Blue Removal over TiO/AC Composites and Photocatalytic Regeneration.

TiO-containing photocatalysts, which combine TiO with carbon-based materials, are promising materials for wastewater treatment due to synergistic photodegradation and adsorption phenomena. In this work, TiO/AC composites were produced by the in situ immobilization of TiO nanoparticles over activated carbon (AC) derived from spent coffee grains, using different TiO/AC proportions. The TiO/AC composites were tested as adsorbents (dark) and as photocatalysts in a combined adsorption+photocatalytic process (solar irradiation) for methylene blue (MB) removal from ultrapure water, and from a secondary effluent (SecEf) of an urban wastewater treatment plant.