MWCNTs/Ag-ZnO nanocomposite for efficient photocatalytic degradation of congo red

Amogne W. Yibeltal,Shimelis Admassie,Abi M. Taddesse,Belete B. Beyene

doi:10.4314/bcse.v34i1.5

Abstract

Three nanomaterials namely, zinc oxide (ZC), silver-doped zinc oxide (AZ) and multi-walled carbon nanotubes coupled with silver doped zinc oxide nanocomposite (MWAZ) were synthesized, characterized and employed for photo degradation of an organic pollutant, congo red (CR). The photocatalytic activity study showed efficient degradation of CR upon irradiation with UV and visible light in the order of MWAZ > AZ > ZC > Commercial ZnO (ZCO). Percentage photodegradation of 99% and a pseudo 1st order rate constant of 2.3 x 10-2 min-1 were achieved by MWAZ as a catalyst under visible light irradiation, implying photo- sensitizing ability of MWCNTs and the capability of MWCNTs to hinder recombination of photogenerated holes and electrons. The control experiment in the dark condition gave only 7.9% of degradation efficiency and 5.56 x 10-4 min-1 rate constant, implying the significant role of light source for catalytic degradation of CR.  Bull. Chem. Soc. Ethiop. 2020, 34(1), 55-66. DOI: https://dx.doi.org/10.4314/bcse.v34i1.5

Highlights

Due to chemical industry and agricultural revolution of 21st century, wide varieties of organic pollutants have been discharged into water systems
This suggests that Ag and multi walled carbon nanotubes (MWCNTs) are incorporated into ZnO lattice, respectively
The X-ray diffraction (XRD) results indicate that all the compositions of nanomaterials give pure hexagonal wurtzite crystalline structure

Summary

Introduction

Due to chemical industry and agricultural revolution of 21st century, wide varieties of organic pollutants have been discharged into water systems. We employed co-precipitation technique to grow the silver-doped ZnO on the surface of MWCNTs. The as-synthesized materials such as zinc oxide (ZC), silver-doped zinc oxide (AZ) and multi-walled supported silver-doped zinc oxide (MWAZ) were employed for photocatalytic degradation of an organic pollutant (congo red) up on irradiation of UV and Visible light sources.

Results

Conclusion