Removal of Azo Dyes Reactive Black from Water by Zero-Valent Iron: The Efficiency and Mechanism

Abstract

The removal kinetics and mechanism of active black removal by zero-valent iron were investigated. The experimental results showed that the rate of reactive black removal by zero-valent iron increased with the decreasing of pH and initial dye concentration, and increased with the increasing of temperature and ZVI dosage. SO42- promoted the removal rate of reactive black. Ca2+ had an inhibitory effect on the removal of reactive black in the early stage by zero-valent iron and promoted it in the later stage, while Mg2+, CO32-, ClO4-, NO3-, PO43- and HCO3- all inhibited the removal rate of reactive black by zero-valent iron. The activation energy was 26.38 KJ mol-1 by using the Arrhenius formula, indicating that this reaction was easy to occur. The degradation process was further analysed by UV-Vis, SEM and XRD, and the main reaction product was Fe2O3.

Keywords

• azo dyes, reactive black, zero-valent iron, removal kinetics