Photothermal catalytic degradation of textile dyes by laccase immobilized on Fe3O4@SiO2 nanoparticles

Efficient and convenient degradation of industrial organic pollutants are of great importance for green chemical schemes and cost-effectiveness. This work introduced the immobilization of laccase on Fe3O4@SiO2 nanoparticles (Fe3O4@SiO2-laccase) for photothermal catalytic degradation of textile dyes. The Fe3O4@SiO2-laccase presented excellent reusability, improved thermal and pH stabilities, and remarkable organic compounds, inhibitors and metal ions tolerance. Batch experiments indicate that the maximum loading amount and activity recovery for laccase were about 10.5 mg/g and 109.7%, respectively. Meanwhile, the immobilized laccase was employed for photothermal catalytic degradation of textile dyes. The degradation assays revealed that the initial removal efficiencies were 99.6%, 99.5%, 94.6%, 94.2%, 89.4% and 79.3% for high concentrations of malachite green (MG), brilliant green (BG), reactive blue 19 (RB19), azophloxine, procion red MX-5B and alizarin red in 30–60 min illumination, respectively. Even after 10 recycling cycles, the photothermal catalytic degradation rates of the textile dyes were observed at 98.7%, 99.3%, 88.8%, 79.0%, 78.7% and 64.4%, respectively. The outstanding photothermal catalytic performances demonstrated that the Fe3O4@SiO2-laccase has a technical application in wastewater treatment.