Removal of phenol by enzymatic oxidation and flotation

Abstract

This work presents a process for phenol removal comprising a reaction step in which phenol is polymerized in the presence of an enzyme followed by a separation step involving dissolved air flotation (DAF). A crude preparation from horseradish roots was used as a low purity source of the enzyme horseradish peroxidase (HRP). The technical feasibility of the process was studied at bench scale using 1 to 10 mM synthetic phenol solutions. Experimental results showed the potential of the proposed technique. A phenol conversion higher than 99 % was observed at the polymerization step and an efficiency higher than 94 % was achieved at the separation stage. Despite the use of a low purity source of HRP, which increases the input of organic matter, the chemical oxygen demand (COD) decreased by 50 %.