ZnO Nanorods Grown on Flexible Polyurethane Foam Surfaces for Photocatalytic Azo Dye Treatment

Abstract

A flexible photocatalyst hybrid structure made up of aligned ZnO nanorods and three-dimensional networks of polyurethane (PU) foam struts was fabricated. The surfaces of the PU struts were first functionalized by the two-step chemical solution treatment method. The functional groups of the PU foam and the nanohybrid structure were characterized using Fourier transmission infrared spectroscopy (FTIR). Their crystal structures and morphologies were examined by using X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The adequacy of the chemical surface modification process was examined by analyzing the differences in the −N � C � O and O−H regions of the FTIR spectrum. The hybrid photocatalyst samples were also tested in terms of their structural integrities under ultrasonic irradiation. It was observed that the ZnO layers remained intact and adherent on the surfaces even after 1 h of sonication. The optical properties of the samples were also characterized by ultraviolet−visible (UV−vis) and photoluminescence (PL) spectroscopies. Aqueous Acid Red 88 (AR88) azo dye solutions were prepared and used to assess both the color and the total organic carbon (TOC) removal efficiencies of the samples utilizing the laboratory-scale photoreactor. The maximum color removal of 97% was reached in 180 min under UVA light irradiation as a consequence of simultaneous adsorption and photocatalysis mechanisms.

FTIR Monitoring of Polyurethane Foams from Acid-Liquefied and Base-Liquefied Derived Polyols

“…The carbonyl peak has its maximum absorbance at 1710 cm -1, which is associated to hydrogenbonded urethane carbonyl, while free urethane absorbs at 1730 cm -1 [40][41][42]. The shoulder at 1670 cm -1 is due to urea carbonyl [43].…”

The Evolution of Sonochemistry: From the Beginnings to Novel Applications

“…[160] The morphology of the NPs is not limiting for the preparation of nanocomposites; for example, Kardeş et al (2023) coated ZnO nanorods with polyurethane employing USI. [161] Sonochemistry presents a noticeable potential for the fabrication of NMs with optimal properties at reasonable costs and minimum environmental impacts. The main limitation of the nanomaterials' synthesis with sonochemistry is the energy efficiency of the high ultrasonic irradiation.…”

Metal and Metal Oxide Nanoparticle Incorporation in Polyurethane Foams: A Solution for Future Antimicrobial Materials?

“…Besides antimicrobial applications (including water disinfection), the developed PU foam composites were tested for use as sensors, in electromagnetic shielding [49] and in pollutant removal [50,53]. Cu (either as a metal or as metal oxide nanoparticles), Zn (in its oxidized form) or silver ions or salts are also widely presented as PU foam reinforcements [12,14,[54][55][56][57][58][59][60][61][62][63][64][65][66][67][68], either for antimicrobial applications [54][55][56][57][61][62][63][64], environmental protection applications [14,54,56,60,64,66,68], as flame retardants [57,65], in electromagnetic shielding [58] or other miscellaneous applications [59,67]. Other forms of ex situsynthesized NPs, such as MgO, Au, W, TiO 2 , Pd, Fe 3 O 4 , Al 2 O 3 , SiO 2 or Ni, have been explored in the literature for incorporation in PU foams [26,31,65,[69]…”