ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Oxygen deficiency induction and boundary layer modulation for improved adsorption performance of titania nanoparticles

Kingsley Igenepo John, Malachy Obu, Aderemi Timothy Adeleye, Victor Ebiekpe, Abraham Abdul Adenle, Haibo Chi, Orege Joshua Iseoluwa, and Martins O. Omorogie

Department of Pure and Applied Chemistry, College of Natural and Applied Sciences, Veritas University, Abuja, Nigeria

E-mail: omorogiem@run.edu.ng

Received: 2 December 2021  Accepted: 9 February 2022

Abstract:

The use of titania (TiO₂) nanoparticles as adsorbents for the adsorption of organic pollutants has attracted the attention of researchers over the years due to their stability, innocuousness, and economic cost. However, their adsorption performance has been limited, and various strategies are being explored to improve this. Herein, we demonstrated the induction of oxygen deficiency and modulation of the boundary layer of TiO₂ through high-temperature treatment as a strategy for enhancing its adsorption performance. The high-temperature-treated samples denoted that HT-TiO₂ was prepared by subjecting commercial Degussa P25 TiO₂ to calcination at 700 ℃ for 2 h. Pristine samples designated Pr-TiO₂ was utilized for comparison. The morphology, crystallinity, bulk elemental composition, and surface area of the samples were investigated using scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD), electron diffraction spectroscopy (EDS), and Brunauer–Emmett–Teller (BET), respectively. Except for the morphology and porosity (obtained from nitrogen adsorption–desorption isotherm), both samples displayed varying characteristics. Experimental results reveal better adsorption performance of metronidazole (MNZ) on HT-TiO₂ (q_max = 25.6937 mg/g) compared to Pr-TiO₂ (q_max = 17.9856 mg/g). This phenomenon is attributed to oxygen deficiency and a smaller boundary layer on HT-TiO₂ deduced from the EDS and intra-particle diffusion model.

Keywords: Titanium dioxide; Nanomaterials; Adsorption; Metronidazole

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02126-y

Chemical Papers 76 (6) 3829–3840 (2022)