Biodegradability enhancement of azo dye Direct Orange-26 using UV/Fenton-like process: optimization using response surface methodology

Abstract

a b s t r a c tIn the present study, the enhancement of biodegradability of Direct Orange-26 (azo dye) in aqueous solution by photo-Fenton-like process and nano-Fe 2 O 3 as catalyst was investigated. The effects of initial pH, reaction time, initial concentration of nano-Fe 2 O 3 , and H 2 O 2 dosage on the biochemical oxygen demand (BOD 5 )/chemical oxygen demand (COD) ratio were studied in batch process using response surface methodology. The analysis of variance suggested that the optimal conditions for enhancement of biodegradability of azo dye solution to be counted as a biodegradable effluent are as follows: nano-Fe 2 O 3 concentration of 0.23 g L −1 , H 2 O 2 concentration of 64 mM, pH of 7.5, and the reaction time of 21.66 min. The BOD 5 /COD ratio at optimal condition was predicted to be 0.50 and confirmed by the experimental study. A good agreement between the model prediction and experimental results confirms the reliability of the developed model for BOD 5 /COD ratio.

Dynamic Modelling, Process Control, and Monitoring of Selected Biological and Advanced Oxidation Processes for Wastewater Treatment: A Review of Recent Developments

“…However, some studies affirm the effectiveness of AOPs in diminishing chronic daily intake (CDI) and hazard quotient (HQ) linked to specific recalcitrant pollutants [22,23]. Additionally, numerous studies have proven that AOPs enhance the biodegradability of low-biodegradability wastewater [14,[22][23][24][25] and produce low-toxicity, biodegradable by-products compared to the original pollutants. In some cases, even the complete mineralization of contaminants has been reported [25].…”

Comparative Study on Enhanced Photocatalytic Activity of Visible Light-Active Nanostructures for Degradation of Oxytetracycline and COD Removal of Licorice Extraction Plant Wastewater

“…Due to this, large quantities end up in water, wastewater, and soil as residues. Environmental pollution with licorice causes serious problems for the ecosystem [11][12][13].…”

“…1. Since the BOD 5 /COD ratio of raw LEPW was 0.19 and the minimum BOD 5 /COD ratio, as an acceptable factor for the wastewater to be biodegradable, was 0.4 [12,13] raw LEPW was considered non-biodegradable. All photocatalysts were prepared by the sol-gel method [27].…”

Modelling and Optimization Study on Biodegradability Enhancement of PVA-Contained Wastewater in a Continuous UV/H2O2 photoreactor

“…The best criterion to represent the biodegradability of the wastewater is its BOD5/COD content ratio. Studies show that the biological treatment of the wastewater is applicable and efficient only if BOD5/COD ratio is equal to or greater than 0.4-0.5 [5].Therefore, in this study, in a continuous UV/H2O2 process, the influence of PVA inlet concentration, H2O2 inlet concentration, and hydraulic retention time on the increasing of BOD5/COD ratio of the PVA-contained wastewater will be studied. A mathematical model will be presented to predict the enhancement of wastewater BOD5/COD ratio based on the aforementioned process operating variables.…”

“…The best criterion to represent the biodegradability of the wastewater is its BOD5/COD content ratio. Studies show that the biological treatment of the wastewater is applicable and efficient only if BOD5/COD ratio is equal to or greater than 0.4-0.5 [5].…”