Search

The catalytic membrane, which combines the physical barrier and peroxymonosulfate (PMS)/visible light (Vis)-induced catalytic oxidation functionalities while minimizing biofouling, exhibits great promise as a material for the removal of persistent organic pollutants from wastewater. In this study, three catalytic membranes composed of 2D/2D hybrid g-C 3 N 4 /kaolinite with nitrogen vacancies and modified with different iron species (γ-FeOOH nanosheets, Fe 2 O 3 quantum dots, and Fe single atoms) were prepared via vacuum filtration. Evaluation of the catalytic performance demonstrated that γ-FeOOH nanosheets-modified sample exhibited a relatively higher water flux (258.13 L m-2 h-1). In contrast, Fe single atom-modified sample achieved improved bisphenol A removal efficiency (97.39%) under the PMS/Vis synergetic system. Interestingly, the Fe 2 O 3 quantum dots-modified sample exhibited the highest rate constant based on the retention time. Furthermore, the Fe single atom-modified sample showed consistent removal of bisphenol A, reaching nearly 100% during continuous-flow operation for 180 min, while maintaining a flux of approximately 200 L m-2 h-1. Quenching experiments suggested that •O 2 −, 1O 2 , and h+ were the most important oxidizing species involved in the reaction of the three membranes. Statistical analysis indicated that variations in the average pore size of the membranes were key factors influencing the catalytic activity. Overall, this study offers an in-depth insight into the systematic and quantitative assessment of 2D/2D hybrid g-C 3 N 4 /layered clay-based catalytic membranes for wastewater treatment. [Display omitted] • The catalytic performance of three iron species-based membranes for bisphenol A removal were compared. • Fe single atom modified membrane showed more superior catalytic performance. • Fe 2 O 3 quantum dots modified membrane possessed the largest rate constant. • The catalytic performance was significantly correlated with surface area and average pore size. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel γ-FeOOH/g-C 3 N 4 /kaolinite composite was fabricated via two-step strategy. • Efficient electron transfer induced by γ-FeOOH and N vacancies promote the separation and migration of photo-generated carriers. • γ-FeOOH/g-C 3 N 4 /kaolinite catalyst possessed good bisphenol A removal efficiency. • The potential synergistic enhancement mechanism was well proposed. A novel ternary composite with the flower-like structure was synthesized by integrating of γ-FeOOH and g-C 3 N 4 /kaolinite containing N vacancies (FNGK). The FNGK-10 composite exhibited the superiority of bisphenol A (BPA) degradation in the presence of peroxymonosulfate (PMS) under the visible-light irradiation with the outstanding reusability and universal applicability, in which the degradation rate constant of FNGK-10/PMS/Vis system was about 3.25 and 8.42 times higher than that of FNGK-10/PMS and FNGK-10/Vis system, respectively. Moreover, the introduction of kaolinite leads to the accelerated consumption of PMS. The FTIR, EPR and XPS spectra proved that the formation of Fe-N and cyano (C≡N) bonds induced the enhancement of the efficiency of electron transfer. The photo-generated carriers could be trapped by N vacancies and γ-FeOOH, which was favorable for the separation potency of photoexcited charge carriers and reduction efficiency of Fe(III) to Fe(II). This paper gave a new perspective on the coupling application of PMS activation and photocatalytic technology to efficiently degrade organic contaminants. [ABSTRACT FROM AUTHOR]