Synergistic effects of Ti3C2 MXene and ZIF-8 for efficient photocatalytic degradation of tetracycline in wastewater

Abstract

Antibiotics in water sources pose increasing risks to human health, highlighting the need for effective and efficient degradation methods. This study focused on improving the degradation of tetracycline (TC) by decorating Ti<inf>3</inf>C<inf>2</inf> MXene nanolayers with zeolitic imidazolate framework (ZIF-8) nanoparticles. The Ti<inf>3</inf>C<inf>2</inf>/ZIF-8 nanocomposites, with several Ti<inf>3</inf>C<inf>2</inf> MXene/ZIF-8 ratios were synthesized using an in-growth technique ensuring ZIF-8 deposition on the surface of Ti<inf>3</inf>C<inf>2</inf> layers. The photocatalytic performance of the samples under UV light irradiation was evaluated. The best results were obtained for the nanocomposite TZ0.1, which degraded to 76 % of TC within one hour, significantly improving degradation efficiency compared to pure ZIF-8 (42 %). Radical scavenging experiments, corroborated by electron paramagnetic resonance (EPR) spectroscopy, revealed that superoxide radical anions (O<inf>2</inf>•¯) and holes (h+) dominated the degradation process. Mott-Schottky analysis confirmed favorable band alignment and the formation of a Schottky junction, supporting the proposed charge transfer mechanism. In addition, the hydrophilic nature of Ti<inf>3</inf>C<inf>2</inf> mitigated the hydrophobicity of ZIF-8, as further supported by contact angle measurements, enhancing dispersibility of composite in aqueous environment and pollutant accessibility. The nanocomposite exhibited high stability over multiple runs and retained more than 64 % degradation efficiency after 10 cycles. This approach presents a promising avenue for improving the photocatalytic activity of metal-organic frameworks by combining them with MXenes to degrade organic pollutants from water.