Photocatalytic process augmented with micro/nano bubble aeration for enhanced degradation of synthetic dyes in wastewater

Abstract

This research combines TiO2 nanopowder photocatalyst (TNP) with micro/nano bubble aeration (MNBA) to enhance the dye degradation of the photocatalytic process treating synthetic dye wastewater. The experimental synthetic dyes were indigo carmine (IC) and reactive black 5 (RB5). The dye degradation performance of the photocatalytic process without MNBA (TNP ​+ ​UVA) and with MNBA (TNP ​+ ​UVA ​+ ​MNBA) under various initial dye concentrations were evaluated. The results showed that, given the initial IC and RB5 dye concentrations of 2 ​μM, the degradation efficiency of TNP ​+ ​UVA and TNP ​+ ​UVA ​+ ​MNBA were 100%. With higher dye concentrations (4–10 ​μM), the degradation efficiency of TNP ​+ ​UVA and TNP ​+ ​UVA ​+ ​MNBA were between 84.05-98.20% and 90.64–100%. The kinetics of the photodegradation reaction of both dyes were described by the Langmuir-Hinshelwood kinetic model. The pseudo first order degradation rate constants of the photocatalytic process with MNBA were 1.44 and 1.66 times higher than those without MNBA for IC and RB5.

Keywords

• Dissolved oxygen
• Indigo carmine
• Langmuir-Hinshelwood
• Photooxidation
• Reactive black 5