Self-sensitized photodegradation and adsorption of aqueous malachite green dye using one-dimensional titanium oxide nanofilaments

Adam D Walter; Hiba Benamor; Lucas M Ferrer; Treesa Reji; Tracey Curran; Gregory R Schwenk; Mohamed Hadji; Megan A Creighton; Michel W Barsoum

doi:10.1016/j.isci.2024.110647

Self-sensitized photodegradation and adsorption of aqueous malachite green dye using one-dimensional titanium oxide nanofilaments

iScience. 2024 Aug 3;27(9):110647. doi: 10.1016/j.isci.2024.110647. eCollection 2024 Sep 20.

Authors

Adam D Walter¹, Hiba Benamor², Lucas M Ferrer¹, Treesa Reji¹, Tracey Curran³, Gregory R Schwenk¹, Mohamed Hadji², Megan A Creighton⁴, Michel W Barsoum¹

Affiliations

¹ Department of Materials Science and Engineering, Drexel University, Philadelphia, PA, USA.
² Laboratoire d'Etudes et Recherche en Technologie Industrielle, Université of Saad Dahlab Blida 1, Blida, Algeria.
³ Academy of Natural Sciences of Drexel University, Philadelphia, PA, USA.
⁴ Department of Chemical and Biological Engineering, Drexel University, Philadelphia, PA, USA.

Abstract

Truly one-dimensional titanium oxide nanofilaments with a lepidocrocite structure (1DLs) were explored in the adsorption and photocatalytic degradation of aqueous malachite green (MG), a toxic polluting dye. Decolorization is monitored by ultraviolet-visible spectroscopy, and mineralization is confirmed by total organic carbon analysis. The 1DL/MG flocs are characterized by scanning electron microscopy and X-ray diffraction. 1DLs, a colloidal nanomaterial, exhibit flocculating behavior while demonstrating high affinity for MG, with a maximum uptake of >680 mg/g rapidly via ion exchange. Additionally, 1DLs decolorize MG under visible light only, unlike most available titania products, via a self-sensitization effect. MG is decolorized by 1DLs by >70% in 30 min under 1 sun exposure of visible light. Counterintuitively, dye adsorption increases as the normalized concentration by mass of 1DL decreases. Demonstrating high adsorption capacity and dye mineralization supports the use of 1DLs in water treatment and self-sensitization for photoelectrochemical devices, like solar cells.

Keywords: Materials science; Nanotechnology; Physics.