A joint research by Professor Can Wang from Tianjin University and Professor Zhurui Shen from Nankai University has shown that the newly synthesized material, TiO2/monolayer Ti3C2Tx (T/mT), holds great potential in highly efficient and environmentally friendly bioaerosol disinfection.
The research team prepared monolayer Ti3C2Tx by etching and exfoliating Ti3AlC2, and then synthesized T/mT through a one-step solvothermal method. The abundant functional groups on the surface of Ti3C2Tx enhance the hydrophilicity and surface free energy of the composite material. The Schottky heterojunction formed between Ti3C2Tx and TiO2 generates a built-in electric field, which prolongs the lifetime of photogenerated electrons and significantly boosts the photocatalytic reaction activity. The research, by means of various testing methods, has confirmed the advantages of T/mT in terms of structure, photoelectric properties, etc. The synthesized material was loaded onto a soft polyurethane sponge and placed in a photoreaction chamber. The constructed device enables effective contact between microorganisms and photocatalyst particles. Under the strong oxidation of ultraviolet light and ROS, T/mT can achieve a sterilization efficiency of 3.3 log in just 12.8 seconds, far exceeding the 1.12 log of TiO2, and it conforms to pseudo-first-order reaction kinetics.
Due to the short quenching time of ROS, the reaction between microorganisms and the photocatalyst depends on physical adsorption, and the monolayer Ti3C2Tx helps with their combination. The monolayer Ti3C2Tx promotes the combination of the photocatalyst with the biological structure. T/mT binds tightly to Escherichia coli cells and has a high affinity for the proteins in the cell membrane. Molecular docking calculations indicate that 2MHL outer membrane proteins are more likely to bind to T/mT. It contains various interactions (Hydrogen bonding, metal-acceptor interactions, etc) that promote the adsorption of the material onto the cell membrane, which is beneficial for further oxidation reactions.
The two-phase of TiO2/monolayer Ti3C2Tx generates a space-charge layer under the action of an electric field, facilitating the separation and transfer of photogenerated electrons and holes. ·O2⁻ and ·OH drive the disinfection process. Photocatalysis damages key structures such as proteins, phospholipids, and polysaccharides in Escherichia coli, gradually mineralizing it. ATR-FTIR, Raman and XPS spectra show that the adsorbed bacterial cells suffer severe physical damage under photocatalysis.
This research achievement not only paves the way for the molecular-level structural design of photocatalytic air disinfection technology, but also serves as a cornerstone for the in-depth exploration of interfacial reactions in photocatalytic disinfection processes. It vividly showcases the remarkable potential of advanced oxidation technologies in effectively handling bioaerosol. Moreover, it holds far-reaching significance in propelling the continuous progress and innovation of air disinfection technologies, opening up new horizons for the development of this field.
Author Introduction:
Can Wang, male, is a professor and doctoral supervisor at Tianjin University, and the head of the Department of Environmental Engineering at Tianjin University. He has long been engaged in research on the utilization and control of environmental microorganisms.
Research Team Introduction:
The Gas Utilization and Control Team of Tianjin University focuses on environmental microorganisms and develops highly efficient biological purification technologies for environmental pollutants and biological control technologies for harmful microorganisms. The research directions of the team members include: biological purification technology for organic waste gases, detection and control of bioaerosols, water and air disinfection technologies, the fundamentals of catalytic reactions and their applications in biological control, and wastewater reuse technologies (membrane-based/electrochemical). It mainly involves basic and applied research in various fields such as environment, biology, chemistry, chemical engineering, materials, and medicine. Team members have published over 100 SCI-indexed papers and undertaken more than 30 scientific research projects, including national science and technology major projects, National Natural Science Foundation projects, Doctoral Program Foundation of the Ministry of Education, and the Beiyang Scholar Program. The team currently has 4 faculty members and over 40 master's and doctoral students.
