Fabrication of a ZGTPM nanocomposite membrane for the synergistic removal of tetracycline via size selective sieving and photocatalytic degradation

This study synthesized a multifunctional ZGTPM nanocomposite membrane (ZIF-8/graphene oxide/Ti₃C₂ MXene/TiO₂ photocatalytic membrane), which combined ZIF-8 (zeolitic imidazolate framework 8), graphene oxide (GO), Ti₃C₂ MXene (two dimensional transition metal carbide), and TiO₂ quantum dots, for the ultraeffective removal of tetracycline (TC) from polluted water. Comprehensive characterization confirmed the formation of TiO₂ quantum dots (3–5 nm) which enhanced membrane properties. Incorporating hybrid nanofillers increased specific surface area from 41.3 to 126.8 m2 g⁻1 and improved hydrophilicity, reducing water contact angle from 78.5° to 43.2°. Consequently, the pure water flux increased by approximately 80%, from 216 to 389 L·m⁻2·h⁻1 at an operating pressure of 1 bar, due to structural and surface improvements which enhanced separation performance and interaction with tetracycline molecules. Performance evaluation showed a tetracycline removal efficiency of over 99.5%, with an adsorption capacity of 82.4 mg g⁻1 at 298 K, following the Langmuir isotherm and pseudo second order kinetics. Photocatalytic tests under simulated solar irradiation achieved a degradation efficiency of 68% within 120 min. Thermodynamic analysis revealed the process was spontaneous, endothermic, and entropy driven, indicating favorable interactions between tetracycline molecules and the membrane surface. Mechanistic studies indicate that adsorption is the primary process in the dark, while photocatalytic degradation is significant under light due to reactive oxygen species from TiO₂ quantum dots and MXene charge transfer pathways. The ZGTPM membrane showed over 97% removal efficiency after five reuse cycles, demonstrating its efficiency and sustainability for treating antibiotic contaminated wastewater.