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Enhanced Photocatalytic Activity using Layer‐by‐Layer Electrospun Constructs for Water Remediation
Author(s) -
Lee Jung Ah,
Nam Yoon Sung,
Rutledge Gregory C.,
Hammond Paula T.
Publication year - 2010
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201000418
Subject(s) - materials science , photocatalysis , bisphenol a , chemical engineering , oxidizing agent , nanoparticle , anatase , reaction rate constant , nanofiber , colloid , catalysis , nanotechnology , kinetics , organic chemistry , chemistry , composite material , physics , quantum mechanics , epoxy , engineering
Endocrine disruptors such as bisphenol A (BPA) are environmental pollutants that interfere with the body's endocrine system because of their structural similarity to natural and synthetic hormones. Due to their strong oxidizing potential to decompose such organic pollutants, colloidal metal oxide photocatalysts have attracted increasing attention for water detoxification. However, achieving both long‐term physical stability and high efficiency simultaneously with such photocatalytic systems poses many challenges. Here a layer‐by‐layer (LbL) deposition approach is reported for immobilizing TiO 2 nanoparticles (NPs) on a porous support while maintaining a high catalytic efficiency for photochemical decomposition of BPA. Anatase TiO 2 NPs ≈7 nm in diameter self‐assemble in consecutive layers with positively charged polyhedral oligomeric silsesquioxanes on a high surface area, porous electrospun polymer fiber mesh. The TiO 2 LbL nanofibers decompose approximately 2.2 mg BPA per mg of TiO 2 in 40 h of illumination (AM 1.5G illumination), maintaining first‐order kinetics with a rate constant ( k ) of 0.15 h −1 for over 40 h. Although the colloidal TiO 2 NPs initially show significantly higher photocatalytic activity ( k ≈ 0.84 h −1 ), the rate constant drops to k ≈ 0.07 h −1 after 4 h of operation, seemingly due to particle agglomeration. In the BPA solution treated with the multilayered TiO 2 nanofibers for 40 h, the estrogenic activity, based on human breast cancer cell proliferation, is significantly lower than that in the BPA solution treated with colloidal TiO 2 NPs under the same conditions. This study demonstrates that water‐based, electrostatic LbL deposition effectively immobilizes and stabilizes TiO 2 NPs on electrospun polymer nanofibers for efficient extended photochemical water remediation.