Degradation of 2,4-diclorophenol via coupling zero valent iron and hydrodynamic cavitation for sulfite activation: A turbulence modeling

Abstract

The 2,4-dichlorophenol (2,4-DCP) is an important chemical precursor that can affect human endocrine system and induce pathological symptoms. This research reports the degradation of 2,4-DCP using lab-scale hydrodynamic cavitation (HC) approach, which is considered a green and effective method. To promote the degradation efficiency, the zero-valent iron (Fe0) as the catalyst for sulfate radical (SO4•−) generation via activation of sulfite (SO32−) salts was simultaneously used. Degradation efficiency was favorable in acidic pH than the alkaline pH due to higher production of active radicals and was dependent on the dose of Fe0 and SO32−. Under optimal condition, degradation efficiency by Fe0/HC/sulfite (96.67 ± 2.90%) was considerably enhanced compared to HC alone (45.37 ± 2.26%). Quenching experiments suggested that SO4•−, •OH, 1O2, and O2•− radicals were involved in the degradation of 2,4-DCP by Fe0/HC/sulfite process, but the dominant role was related to •OH (70.09% contribution) and SO4•− (29.91% contribution) radicals. From the turbulence model, turbulent pressure at venturi throat decreased from −0.42 MPa to −2.02 MPa by increasing the inlet pressure from 1.0 to 4.0 bar and increase in pressure gradient has intensified bubble collapse due to higher turbulence tension.