Surface‐Engineered 2D Bimetallic FeNi‐MOFs Derived from Layered Double Hydroxides for Photocatalytic Membranes with Enhanced Dye Fixation in Wastewater Treatment

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 21; no. 6; pp. e2409133 - n/a
• Main Authors: Karthikeyan, Gayathri, Mohan, Sakar, Austeria, P. Muthu, Balakrishna, R. Geetha
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.02.2025
• Subjects: Bimetals; Charge efficiency; Charge transfer; Density functional theory; DFT computational modeling; Dyes; Hydrogen bonds; Hydroxides; layered double hydroxide; Leaching; membrane; Membranes; Metal-organic frameworks; metal‐organic framework; Photocatalysis; Photodegradation; Polysulfone resins; Rejection rate; Rhodamine; Terephthalic acid; Wastewater treatment; Water treatment; metal‐organic framework; membrane; layered double hydroxide; photocatalysis; DFT computational modeling; wastewater treatment
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.202409133

FeNi‐based layered double hydroxides (LDHs) are used as precursors to derive bimetallic FeNi‐metal organic frameworks (D‐FeNi MOFs) with terephthalic acid ligands, offering enhanced properties compared to conventionally prepared FeNi‐MOFs (C‐FeNi MOFs). D‐FeNi MOFs exhibited superior structural, surface, and electrochemical features, confirmed by density functional theory (DFT) studies, which also predicted their catalytic mechanism. Band edge potential calculations through Mott–Schottky analysis revealed their favorable redox potential, enhanced charge transfer, and reduced recombination resistance, explaining their superior photocatalytic efficiency. D‐FeNi MOFs degraded 91% of rhodamine B (RhB) and 89% of Congo red (CR), outperforming C‐FeNi MOFs, which degraded 84% and 77%, respectively. These MOFs are incorporated (3, 5, and 7 wt%) into polysulfone (PSU) membranes to develop photocatalytic membranes. The 7 wt% membranes (FNM7) exhibited high water flux (54.4 L m−2h−1) and dye flux (≈51.1 and 41.6 L m−2h−1) with rejection rates of ≈88% and 90% for RhB and CR, significantly surpassing bare membranes. FNM7 demonstrated superior anti‐fouling and photocatalytic regeneration (12.9% RhB, 9.6% CR degradation under sunlight) across three cycles. DFT studies showed FeNi centers weaken dye molecule bonds, aiding degradation, while carboxyl groups in MOFs formed robust hydrogen bonds with PSU, ensuring no particle leaching. This highlights D‐FeNi MOF‐membranes as an efficient system for wastewater treatment. The study explores FeNi‐MOFs derived from LDH precursors and their advantages over conventional methods, focusing on synthesis, structural and photocatalytic properties. It highlights the superior dye degradation efficiency and catalytic mechanism of LDH‐derived FeNi MOFs, analyzed through both experimental and theoretical (DFT) studies, and their incorporation into polysulfone membranes, demonstrating improved flux, rejection, anti‐fouling, and stability for wastewater treatment applications.