Photocatalytic and Magnetic Porous Cellulose-Based Nanocomposite Films Prepared by a Green Method

Abstract

The present work expands our previous studies related to cellulose processing with room-temperature ionic liquids and simultaneous integration of functional nanoparticles toward photocatalytically active and easily recyclable nanocomposite porous films based on a renewable matrix material. Porosity can be tuned by the selection of phase separation conditions for the films obtained from the casting solutions of cellulose in ionic liquids or their mixture with an organic cosolvent. TiO 2 nanoparticles confer to the nanocomposite photocatalytic activity, while Fe 3 O 4 nanoparticles make it magnetically active. The photocatalytic activity of the cellulose film containing 10 mg of TiO 2 was 1 order of magnitude lower than that of the same amount of pure TiO 2 nanopowder, due to the reduction of the active catalytic surface which can be reached by UV irradiation after embedment in the polymer matrix. However, this fixation in a solid polymer support allows facile recovery of the catalyst after use. The rate constant when using the cellulose nanocomposite doped with TiO 2 and Fe 3 O 4 (k ≈ 0.0019 min −1 ) is very close to that for the corresponding composite containing only TiO 2 (k ≈ 0.0017 min −1 ), suggesting that co-doping with Fe 3 O 4 nanoparticles did not diminish the photocatalytic activity of the final composite, which can be easily separated from solution with a magnet. Additionally, by Fe 3 O 4 doping, the composite material's temperature can be homogeneously increased by ∼12 K via exposure to a high-frequency alternating magnetic field (AMF) for 5 min. For an optimal thermal response to AMF, the magnetite nanoparticles have to be homogeneously dispersed within the polymer matrix. The preparation method for the casting solution has been found to play an essential role for the one-step fabrication of multifunctional cellulose-based nanocomposite materials.

Green and Economical Strategy for Spinning Robust Cellulose Filaments

“…Figure a illustrates the FTIR spectra of the wood pulp and NCF-1.8. The peak of wood pulp at 1432 and 1120 cm –1 assigned to the cellulose I crystal exhibited a sharp drop in NCF-1.8. , The wood pulp exhibited three crystal peaks (Figure b) of 14.8, 16.3, and 22.6°corresponded to crystal planes (11̅0), (110), and (020) of cellulose I . The regenerated cellulose fibers displayed three crystal peaks at 12.1, 19.8, and 22.0° assigned to the crystal planes (11̅0), (110), and (020) of cellulose II. , These results demonstrated that the crystal structure of the cellulose fibers transformed from cellulose I to cellulose II during the filament production process.…”

“…The peak of wood pulp at 1432 and 1120 cm −1 assigned to the cellulose I crystal exhibited a sharp drop in NCF-1.8. 39,40 The wood pulp exhibited three crystal peaks (Figure 5b) of 14.8, 16.3, and 22.6°corresponded to crystal planes (11̅ 0), (110), and (020) of cellulose I. 41 The regenerated cellulose fibers displayed three crystal peaks at 12.1, 19.8, and 22.0°assigned to the crystal planes (11̅ 0), (110), and (020) of cellulose II.…”

Magnetic cellulose: does extending cellulose versatility with magnetic functionality facilitate its use in devices?

“…In situ incorporation Ex situ incorporation Iron oxide Co-precipitation in cellulose matrix: cellulose suspension, 47,48,51 cellulose solution 49,50,[56][57][58] Preformed particles: added to cellulose solution; 49,[52][53][54][55][59][60][61][62] surface modification of cellulose prior; 63 using a retention aid 71 Hydrothermal methods 68…”

“…56,57 Cellulose xanthate, that is a soluble intermediate in viscose production and can be regenerated to cellulose, was functionalized with iron oxide particles by adding premade particles as well as in a one-step synthesis by adding an iron source into the xanthate solution. 49 Furthermore, ionic liquids are a rather new class of cellulose solvents, which are already being used in preparing magnetically functional cellulose: ionic liquids have been used to dissolve the cellulose and iron salts for co-precipation, 58 mixing together, [59][60][61][62] or grafting 63 the cellulose and magnetic component. Ionic liquids were also used as a solvent for dissolution and regeneration in the sol-gel transition method to produce cellulose-chitosan magnetic composites.…”

Polivinil borat/TiO2 Nanokompozitlerin Fotokataliz Uygulaması

“…Son yıllarda atıksu arıtımında boya giderimi üzerine yapılan çalışmalarda, TiO 2 fotokatalizörün polimer matrikse tutturularak kullanımının önemine dikkat çekilmiştir. Literatürde, polidisiklopentadien/TiO 2 [8], düşük yoğunluklu polietilen/TiO 2 ve yüksek yoğunluklu polietilen/TiO 2 [7], selüloz/TiO 2 [9], poli(metil metakrilat)/TiO 2 [5], hidroksiapetit/poliakrilat/ TiO 2 [10], politetrahidrofuran-üretan dimetakrilat/TiO 2 [11], polipirol/TiO 2 [12] ve poli (3-heksiltiyofen)/TiO 2 [13] kompozit sistemlerinin fotokatalitik etkinliği çalışılmıştır. Belirtilen polimer matrikslerindeki TiO 2 fotokatalizörünün fotokatalitik etkinliği, model boyanın su ortamında bozunması ile tespit edilmiştir.…”