Boosting Fe(III)/Fe(II) cycling under visible-light-driven TiO2-based membrane with electron-deficient center for wastewater decontamination

The advanced oxidation process (AOP) based on hydroxyl radical ( • OH) has garnered increasing attention in water purification and wastewater treatment . However, producing • OH by activating hydrogen peroxide (H 2 O 2 ) encounters the challenges associated with the sluggish kinetics of Fe(II) regeneration. Herein, we developed a carambola-like catalyst of boron (B)-doped TiO 2 mesocrystals-based iron catalyst (Fe-B-MST), which served as a photocatalyst to modulate the regeneration of Fe(II) in photo Fenton-like systems. We successfully used the electrospinning method to gain membrane and realised the remediation of different industrial wastewater. The Fe-B-MST catalyst exhibits excellent efficiencies in the oxidative degradation of 4-chlorophenol (4-CP) pollutants, effectively facilitating the production of • OH while minimising the formation of toxic byproducts, with the first-order kinetic constant ( k = 2.372 min −1 ) being approximately 6.1 times greater than that without B doping, and 19.8 times greater than that observed with commercial TiO 2 . Theoretical calculations and related physicochemical characterisation reveal that B occupies an interstitial site in titania, conferring a sufficiently high valence band potential, making it thermodynamically favourable for H 2 O 2 oxidation and weakening its interaction with • OH, consequently increasing higher reactivity toward the targeted organic pollutant . The B doping facilitates electron transfer , promotes rapid reduction of Fe(III) to Fe(II), and further enhances • OH production via a photo Fenton-like reaction. The oxidation reaction stoichiometry efficiencies were quantified for different organics and calculated to be in the range of 7.70–24.20 % in Fe-B-MST/H 2 O 2 vis. system, representing an enhancement of 1.18–1.54 times compared to Fe-MST/H 2 O 2 vis. , alongside the utilisation efficiency of H 2 O 2 ( η ) of Fe-B-MST/H 2 O 2 vis. is 1.37–1.67 fold greater than that of Fe-MST/H 2 O 2 vis. after 30 min of reaction. This study expands our understanding and provides valuable insights into applying photocatalysis for enhanced wastewater treatment . The boron doping facilitates electron transfer , promotes the rapid reduction of Fe(III) to Fe(II), and further enhances hydroxyl radical production through a Fenton-like reaction, resulting in higher stoichiometric efficiency and improved utilisation efficiency of hydrogen peroxide. • Fe-B-MST efficiently photo-catalyzes H 2 O 2 for organic pollutant removal. • Fe and B lower the band gap and extend visible light absorption. • B regulates Fe(II) regeneration in photo-Fenton-like systems. • The membrane device shows long-term stable wastewater remediation performance.