Electro-oxidation by graphite anode for naphthenic acids degradation, biodegradability enhancement and toxicity reduction
| Autor: | Yanyan Zhang, Abdallatif Satti Abdalrhman, Mohamed Gamal El-Din |
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| Rok vydání: | 2018 |
| Předmět: |
Environmental Engineering
Graphite anode 010504 meteorology & atmospheric sciences Carboxylic Acids Fraction (chemistry) 010501 environmental sciences 01 natural sciences Waste Disposal Fluid Environmental Chemistry Reactivity (chemistry) Waste Management and Disposal Effluent Electrodes 0105 earth and related environmental sciences Chemistry Electrochemical Techniques Biodegradation Pollution Aliivibrio fischeri 6. Clean water Biodegradation Environmental 13. Climate action Toxicity Degradation (geology) Oil sands Graphite Oxidation-Reduction Water Pollutants Chemical Nuclear chemistry |
| Zdroj: | The Science of the total environment. 671 |
| ISSN: | 1879-1026 |
| Popis: | Electro-oxidation (EO) by using graphite anode and at relatively low current densities was successfully applied for the degradation of commercial naphthenic acids (NAs) mixture in water samples. At current densities of 0.5, 2.5, and 5 mA/cm2, acid extractable fraction (AEF) was removed by 42.2%, 57.0% and 67.9%, respectively, while classical NAs were degraded by 76.9%, 77.6% and 82.4%, respectively. EO reactivity towards NAs increased with increasing the carbon number (n) and was higher for cyclic NAs compared to the acyclic component. Oxidized NAs containing O3 and O4 were also degraded effectively during EO. The biodegradability of organics in the NA mixture was clearly improved by 1.7, 2.5 and 2.7 folds when the samples were pre-treated with EO at current densities of 0.5, 2.5, and 5 mA/cm2, respectively. The aromatic fraction in the commercial NA mixture consisted mainly of single-ring aromatics and was degraded effectively by EO. Biodegradation alone was able to reduce the toxicity of the commercial NA mixture towards Vibrio fischeri; however, the combination of EO with biodegradation resulted in a complete removal of the toxicity, showing a synergistic effect of combining these two processes. Coupling EO with aerobic biodegradation can result in an effective and energy-efficient treatment option for NA-bearing waters such as oil sands process water (OSPW) and refinery effluents. |
| Databáze: | OpenAIRE |
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