TiO2 Sol-Gel Coated PAN/O-MMT Multi-Functional Composite Nanofibrous Membrane Used as the Support for Laccase Immobilization: Synergistic Effect between the Membrane Support and Enzyme for Dye Degradation

Abstract

Removal of a triphenylmethane dye (crystal violet, CV) by a simultaneous enzymatic-photocatalytic-adsorption treatment was investigated in this work. A desirable synergistic effect on dye treatment was achieved by decorating laccase (Lac) onto the surface of TiO2 sol-gel coated polyacrylonitrile/organically modified montmorillonite (PAN/O-MMT) nanofibers prepared by electrospinning. The assembly of Lac on the surface of PAN/O-MMT/TiO2 nanofibers was confirmed by confocal laser scanning microscope (CLSM). In comparison with free Lac, the immobilized Lac showed better pH, temperature and operational stabilities, reaching highest relative activity at an optimum pH of 3 and optimum temperature of 50 °C. Therefore, the immobilized Lac displayed a higher degradation efficiency of CV at an initial dye concentration of 100 mg/L, an optimum pH of 4.5 and temperature at 60 °C. Under UV illumination, the CV removal efficiency was further improved by ~20%. These results demonstrated that the Lac-immobilized PAN/O-MMT/TiO2 composite nanofibers with a combined effect between the immobilized enzyme and the polymeric support have potential for industrial dye degradation.

Catalytic and Physicochemical Evaluation of a TiO2/ZnO/Laccase Biocatalytic System: Application in the Decolorization of Azo and Anthraquinone Dyes

“…40% of its initial activity. Similar results were obtained when different supports based on TiO 2 and ZnO were used for enzyme immobilization [40][41][42].…”

“…The results (presented in Table 2) show that the immobilization process was carried out with high efficiency (99.4%). Similar effects were received by Wang et al [42], who used TiO 2 sol-gel coated PAN/O-MMT (polyacrylonitrile/organically modified montmorillonite) as a laccase support. In that case, 342 mg of laccase was immobilized on 1 g of support.…”

“…Other publications show that biocatalytic systems based on TiO 2 or ZnO and laccase can also be efficiently applied in the removal of organic dyes (Alizarin Red S, Reactive Black, Malachite Green, Remazol Brilliant Blue R, etc.) from aqueous systems [40][41][42][43][44].…”

An Integrative Approach to Study Bacterial Enzymatic Degradation of Toxic Dyes

“…Paenibacillus glucanolyticus and Bacillus amyloliquefaciens laccase produce non-blue laccases, which have been shown to work in acidic conditions, but the optimum temperature of non-blue laccases was less as compared with present research findings (Chen et al, 2015;Mathews et al, 2016). Recently, a very advanced and innovative technique of immobilizing laccase on the surface of the poly-3 hydroxybutyrate and nanofibers and its effect on the dye degradation were observed by Gil et al (2018) and Wang et al (2020). The molecular structure of laccases has the presence of four copper atoms, which are differentiated according to their properties in the catalytic mechanism into three types: copper I, copper II, and copper III.…”

Facile Synthesis of Lacunary Keggin-Type Phosphotungstates-Decorated g-C3N4 Nanosheets for Enhancing Photocatalytic H2 Generation

“…According to the energy band structures of the reported Keggin-type phosphotungstates and g-C 3 N 4 NSs, the LUMO position is a little higher than the valence band (VB) position of the g-C 3 N 4 NSs, as illustrated in the inset of Figure 5 B. Thus, when the PW 9 /g-C 3 N 4 heterojunction NSs is excited by simulated sunlight that contains the photon energies in both UV and visible light regions, the photoinduced electron-hole pairs are generated on the LUMO and VB of the PW 9 and g-C 3 N 4 hetero-components, respectively [ 41 , 42 ]. Owing to the potential difference between the LUMO of PW 9 and the VB of g-C 3 N 4 , the photoinduced electrons on the LUMO of PW 9 could transfer to the VB of g-C 3 N 4 in the heterojunction NSs, thereby extending the lifetimes of the photoinduced electrons on the CB of g-C 3 N 4 for implementing the photocatalytic H 2 generation [ 43 ].…”