Sequential photocatalysis and biological treatment for the enhanced degradation of the persistent azo dye methyl red

Tatoba R. Waghmode, Mayur B. Kurade, Ramchandra T. Sapkal, Chandrakant H. Bhosale, Byong Hun Jeon, Sanjay P. Govindwar

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

A combination of photocatalysis and biodegradation is a promising approach for the removal of xenobiotic organic compounds from wastewater, since photocatalysis cleaves the molecules into simpler intermediates that are later mineralized by microorganisms. Sequential photocatalytic and biological treatment (SPABT) consisting of ZnO as a photocatalyst and a microbial consortium (Galactomyces geotrichum and Brevibaccilus laterosporus) enhanced the degradation of a model textile dye, methyl red (MR). SPABT completely decolorized 500 mg MR/L within 4 h. Biotreatment alone required 6 h for 100% decolorization. A maximum of 70% decolorization was achieved with the photocatalytic treatment but reductions in COD and toxicity were not adequate. Significant elevated activities of enzymes, including azo reductase, laccase and veratryl alcohol oxidase, were observed in the microbial consortium after exposure of MR. The degradation pathway and products of MR varied with treatment applied. The persistent azo bond was cleaved by following photocatalytic treatment with the microbial biotreatment. Tests with Sorghum vulgare and Phaseolus mungo indicated the products obtained by SPABT were non-phytotoxic.

Original languageEnglish
Pages (from-to)115-122
Number of pages8
JournalJournal of Hazardous Materials
Volume371
DOIs
StatePublished - 2019 Jun 5

Keywords

  • Decolorization
  • Degradation
  • Integrated treatment
  • Microbial consortium
  • Photocatalysis

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