Efficient phenol degradation by laccase immobilized on functional magnetic nanoparticles in fixed bed reactor under high‐gradient magnetic field

Enzymatic degradation of emerging contaminants has gained great interest for the past few years. However, free enzyme often incurs high costs in practice. The immobilized laccase on the polyethylenimine (PEI)‐functionalized magnetic nanoparticles (Fe(3)O(4)–NH(2)–PEI–laccase) was fabricated to efficiently degrade phenolic compounds continuously in a newly fixed bed reactor under a high‐gradient magnetic field. The degradation rate of continuous treatment in the bed after 18 h was 2.38 times as high as that of batch treatment after six successive operations with the same treatment duration. Under the optimal conditions of volume fraction of nickel wires mesh, flow rate of phenol solution, phenol concentration, and Fe(3)O(4)–NH(2)–PEI–laccase amount, the degradation rate of phenol kept over 70.30% in 48 h continuous treatment. The fixed bed reactor filled with Fe(3)O(4)–NH(2)–PEI–laccase provided a promising avenue for the continuous biodegradation of phenolic compounds for industrial wastewater in practice.