Date of Award

5-21-2020

Publication Type

Master Thesis

Degree Name

M.A.Sc.

Department

Civil and Environmental Engineering

First Advisor

Nihar Biswas

Second Advisor

Keith E. Taylor

Keywords

Azo-bond cleavage, Azo-dyes, Mass spectrometry, Soybean peroxidase, Textile industry, Wastewater treatment

Rights

info:eu-repo/semantics/openAccess

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Abstract

Removal of dyes released in water by textile industries presents a major challenge for the researchers. Soybean peroxidase (SBP) has been widely explored for removal of a variety of toxic aromatics consisting of phenolic or anilino functional groups. Also, it has been known to possess the ability of azo-bond cleavage. This thesis was aimed to investigate azo-bond cleavage by SBP in the presence of hydrogen peroxide, if possible, in the absence of these functional groups. Direct Yellow 12 and azobenzene were chosen as a model compounds for this study. Experiments were conducted at a range of pHs, SBP and hydrogen peroxide to investigate the hypothesis. Enzymatic removal of p-anisidine and Methyl Orange (MO) and azo-bond cleavage of MO were also studied. Optimization of pH, hydrogen peroxide-to-substrate ratio and SBP activity were performed to achieve ≥95% removal of these substrates in 3 hours, analyzed using high-performance liquid chromatography. A time course study was conducted to calculate pseudo-first-order rate constants and half-lives for degradation of these compounds. Mass spectrometry analysis showed oligomerization of p-anisidine and for MO, evidence of azo-bond cleavage was obtained after the enzymatic treatment.

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