Impact of the duty cycle on the morphology and photocatalytic properties of S-TiO2 obtained by plasma electrolytic oxidation to treat real electaroplating wastewater contaminated with Cr6+

VARGAS-VILLANUEVA, STEVEN; VELÁSQUEZ-TAMAYO, JUAN PABLO; TORRES-CERÓN, DARWIN AUGUSTO; MERCADO, D. FABIO; TORRES-PALMA, RICARDO A.; RIASSETTO, DAVID; RIVA, JULIETA SOLEDAD; AMAYA-RONCANCIO, S.; CASTILLA-ACEVEDO, SAMIR FERNANDO; RESTREPO-PARRA, ELISABETH

Journal of Environmental Chemical Engineering

Elsevier

Año: 2023

2213-3437

his work reports S-TiO2 doped coatings to reduce Cr6+ to Cr3+ obtained from a Ti electrode through the Plasma Electrolytic Oxidation (PEO) process. The Ti sheets (20 x 20 x 1 mm) were submerged on 0.1 M H2SO4, and values of the duty cycle from 2% to 50% were applied to obtain various materials. SEM, XRD, AFM, XPS, and DRS techniques were used to characterize the resultant surfaces. It was observed that the duty cycle strongly influences the Journal Pre-proof 2 crystalline/amorphous ratio, anatase/rutile ratio, porosity density, pores size distribution, and surface roughness. Besides, it is explained that the introduction of SO4 2- into the TiO2 structure can take place either in the Ti or O places in the crystalline lattice. All materials showed photocatalytic properties to reduce Cr6+ to Cr3+ under UVC light (254 nm), decreasing the efficiency with the increase of the duty cycle. Additionally, the introduction of EDTA showed a positive synergy with the heterogeneous photocatalytic pr