Enhancement of TiO2 activity under visible light by N,S codoping for Pb(II) removal from water

Abstract

This paper deals with a systematic study on the co-doping N,S on TiO2 photocatalyst to improve its activity under visible light on the removal of Pb(II) from the aqueous media. The co-doping TiO2 by N,S atoms was conducted in an autoclave by one-step hydrothermal of TiO2 mixed with nitric and sulfuric acids as the sources of N and S, respectively. The mole ratio of TiO2:nitric acid:sulfuric acid was varied as 1:1:0.5, 1:1:1, and 1:1:1.5 to find the best ratio toward the activity. The co-doped photocatalysts obtained were characterized by specular reflectance UV/Vis (SRUV), X-ray diffraction (XRD), and fourier transform infrared (FTIR) instruments. A batch experiment was carried out for oxidation of Pb(II), driven by a combination of visible light and TiO2-N,S photocatalyst. The research results attribute that co-doping N,S into TiO2 has remarkably narrowed the gap in the TiO2 structure, emerging in the visible region. It was also proven that the co-doped in TiO2 can considerably enhance its activity in the removal of Pb(II) under visible light, and the highest activity was owned by TiO2-N,S (1:1:1). Furthermore, the most effective removal of Pb(II) 10 mg/L (98%) could be reached by employing 500 mg L-1 of the TiO2-N,S (1:1:1) dose, 45 min of the time, and the solution pH at 7. The Pb(II) removed is due to the photo-oxidation induced by OH radicals to form the handleable PbO2.

Adsorción de iones de Pb2+ empleando CaCO3 biogénico en soluciones acuosas

“…Diversos sistemas de tratamientos se han desarrollado para la eliminación de estos contaminantes metálicos del agua; entre ellos se encuentran la floculación, la coagulación, la oxidación química, la precipitación química, la ozonización, la filtración por membranas, el método de ósmosis inversa y la adsorción (Gupta et al, 2021;Wahyuni et al, 2022). Esta última es considerada como una de las técnicas más efectivas y económicamente viables para el tratamiento de aguas residuales contaminadas por compuestos tóxicos orgánicos e inorgánicos, incluidos los iones de metales pesados, si se utiliza el adsorbente adecuado (Hernandez-Eudave et al, 2016;Reynel-Avila et al, 2015).…”