Tao Tian,Jie Zhang,Lijiang Tian,Sijie Ge,Zhenyu Zhai
Visible-light-enhanced TiO2nanocatalysts doped with Cu and Fe were synthesized using the sol–gel method to investigate their performance in degrading gaseous benzene. The structure and morphology of mono- and co-doped TiO2(i.e., Cu/Fe-TiO2, Cu-Fe-TiO2) were characterized using SEM, EDS, XRD, BET, Raman, UV-vis-DRS, and XPS techniques. The results indicated that the presence of Cu/Fe mono- and co-doped TiO2leads to the formation of an anatase phase similar to pure TiO2. Furthermore, the introduction of Cu/Fe enhanced the presence of lattice defects and increased the specific surface area of TiO2. This enhancement can be attributed to the increase in oxygen vacancies, especially in the case of Cu-Fe-TiO2. Additionally, Cu-Fe-TiO2showed a higher concentration of surface-bound hydroxyl groups/chemically adsorbed oxygen and a narrower bandgap than pure TiO2. Consequently, Cu-Fe-TiO2exhibited the highest photocatalytic performance of 658.33 μgC6H6/(g·h), achieving a benzene degradation rate of 88.87%, surpassing that of pure TiO2(5.09%), Cu-TiO2(66.92%), and Fe-TiO2(59.99%). Reusability tests demonstrated that Cu-Fe-TiO2maintained a high benzene degradation efficiency of 71.4%, even after five experimental cycles, highlighting its exceptional stability and reusability. In summary, the addition of Cu/Fe to TiO2enhances its ability to degrade gaseous benzene by prolonging the catalyst’s lifespan and expanding its photoresponse range to include visible light.
Jieyu Sui,Ruixuan Zhou,Kunyan Sui,Pengfei Qi,Wenxin Fan
The high-efficiency removal of harmful and persistent polycyclic aromatic hydrocarbon (PAH) pollutants from natural water is critical for safeguarding human health. A major challenge lies in the absence of effective technologies to accelerate the transfer of chemically inert and electroneutral PAHs from contaminated water to nano-adsorbents or nano-catalysts. Herein, we present a novel TiO 2 /polycation composite hydrogel membrane featuring dual gradients of positively charged groups and TiO 2 nano-catalysts for the deep and high-efficiency removal of PAH pollutants. The gradient polycation hydrogel matrix facilitates the spontaneous absorption of PAHs through cation-π interactions, while driving the directional migration of PAHs towards the high-density side via enthalpy-driven force induced by the positive charge gradient. Consequently, irradiating the high-density side of the dual-gradient composite hydrogel, enriched with PAHs and TiO 2 nano-catalysts, enables rapid and deep photocatalytic degradation of PAHs (e.g., naphthalene and phenanthrene). Furthermore, a mathematical model based on the Flory-Rehner theory is firstly developed to precisely control the distribution of PAHs within the composite hydrogels. Our findings provide a robust framework for the design of advanced composite catalysts with substantially enhanced removal efficiency for PAH pollutants.
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