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

Modified TiO₂/chitosan-based hydrogel beads for the photocatalytic degradation of dyes and heavy metals for water treatment

Ebtesam A. Mohamad, Esraa M. Sakr, Salma A. Mohammed, Victoria Sotee John, and Haitham S. Mohammed

Radiology and Medical Imaging Department, College of Applied Medical Sciences, Prince Sattam Bin Abdul-Aziz University, Al-Kharj, Saudi Arabia

E-mail: imohamed@sci.cu.edu.eg

Received: 14 April 2024  Accepted: 26 September 2024

Abstract:

Photocatalytic degradation has gained significant attention in treating water as an eco-friendly method and cost-effective solution. Titanium dioxide (TiO₂) is one of the most efficient and non-toxic photocatalysts used in water treatment. The main obstacle facing TiO₂ being applied on a large scale is requiring high light energy, mainly in the ultraviolet region (only 5% of sunlight), to activate the photocatalysts. Lowering the band gap of TiO₂ nanoparticles makes them easily activated by sunlight. Oxygen vacancies (OVs) or Ti³⁺-rich TiO₂ can have a lower band gap and enhance performance. Titanium hydroxide was calcinated in a vacuum to obtain modified TiO₂ and then immobilized in chitosan hydrogel as a great self-healable supporter with high availability and antimicrobial behavior. Characterization was done by using XRD and UV–visible absorbance spectroscopy. Photocatalytic studies were constructed on C.I. Acid Blue 324 as a model for dyes and on Pb, Cu, Cd, and Ni as models for heavy metals using modified-TiO₂ and white-TiO₂ encapsulated in chitosan beads separately under sunlight. The modified TiO₂\chitosan composite has a higher degrading ability than the white one. The study is considered a first step toward making a lifelong solution for water treatment with no power consumption.

Keywords: Photocatalysis; Modified-TiO2; White-TiO2; Oxygen vacancy; Chitosan beads

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-024-03863-y

Chemical Papers 79 (3) 1417–1425 (2025)