Laccase-Carrying Electrospun Fibrous Membranes for Adsorption and Degradation of PAHs in Shoal Soils

Abstract

The removal of polycyclic aromatic hydrocarbons (PAHs) from soil is costly and time-consuming. The high hydrophobicity of PAHs makes PAH diffusion from soil particles by hydraulic flow difficult. The phase transfer of PAHs from soil to another available mediator is crucial for PAH removal. This study focuses on the remediation of PAH-contaminated shoal soil, located in Yangtze, China, using three types of laccase-carrying electrospun fibrous membranes (LCEFMs) fabricated via emulsion electrospinning. These LCEFMs were composed of core-shell structural nanofibers (for PAH adsorption), with laccase in the core (for PAH degradation) and pores on the shell (for mass transfer). The LCEFMs with strong adsorptivity extracted the PAHs from the soil particles, resulting in an obvious enhancement of PAH degradation. The removal efficiencies in 6 h for phenanthrene, fluoranthene, benz[a]anthracene and benzo[a]pyrene were greater than 95.1%, 93.2%, 79.1%, and 72.5%, respectively. The removal half-lives were 0.003-1.52 h, much shorter than those by free laccase (17.9-67.9 h) or membrane adsorption (1.25-12.50 h). The third-order reaction kinetics suggested that the superficial adsorption and internal diffusion were the rate-limiting steps of the overall reaction. A synergistic effect between adsorption and degradation was also proposed on the basis of the triple phase distribution and kinetics analyses.

Laccase Immobilization on Poly(p-Phenylenediamine)/Fe3O4 Nanocomposite for Reactive Blue 19 Dye Removal

“…The activity of immobilized Lac was clearly stabilized compared with that of free Lac. Similar results have been reported for other nanobiocatalysts [37,38].…”

“…Similar results have been reported for catalase covalently bound to electrospun nanofiber meshes filled with carbon nanotubes [40]. It was also reported that the conducting carbon nanotubes were able to promote direct electron transport from redox enzymes such as ascorbate oxidase, peroxidase, and Lac [38,[40][41][42][43][44][45][46]. Therefore, PpPD/Fe3O4 nanocomposite may also be suitable for enzyme immobilization, especially for redox enzymes.…”

Fabrication of a novel immobilization system and its application for removal of anthracene from soil

“…The ANT removal by immobilized mycelia was a thirdorder reaction indicating that the process could be affected by multiple factors. Similar results were observed by a recent report with respect to the removal of PAHs by laccase-carrying electro spun fibrous membranes [33]. Compared with the immobilized mycelia in CA/PCL and CA beads, the removal rate of ANT by the immobilized mycelia in CA/PCL/corn-cobs was much faster.…”

“…It has been reported that the immobilized laccase in most hydrophobic matrices showed the lowest retained activity as the hydrophobic matrices might undermine the conformation stability of laccase [33]. The results confirmed that CA/12% PCL bead was a suitable immobilization system for laccase.…”

“…The kinetic rate constant (k), the reaction half-life (t 1/2 ) can be calculated by the Eqs. (2)-(4) [33]. The ANT removal by the indigenous microorganisms and free mycelia followed the first-order reaction model (Eq.…”