Detoxification of Cyanide Wastewater by Cyanotrophic Organisms: the case of Phanerochaete chrysosporium
| Autor: | G. Ofori-Sarpong, A. S. Adam, R.K. Amankwah |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Lixiviant
biology Cyanide 02 engineering and technology 010501 environmental sciences biology.organism_classification Pulp and paper industry 01 natural sciences 020501 mining & metallurgy chemistry.chemical_compound Hydrolysis 0205 materials engineering chemistry Wastewater Phanerochaete Hydrogen peroxide Effluent Gold extraction 0105 earth and related environmental sciences |
| Zdroj: | Ghana Mining Journal. 20:34-44 |
| ISSN: | 0855-210X |
| DOI: | 10.4314/gm.v20i1.4 |
| Popis: | Cyanide, a carbon-nitrogen radical, is a major building block in many industries including pharmaceuticals, petrochemical and gold processing. In the gold extraction industry, cyanide has been the universal lixiviant for over a century due to better understood process chemistry, among others. Industries that discharge cyanide-laden effluents are mandated to keep concentrations below 0.2 mg/L to prevent death by cyanide-intoxification, which occurs when cyanide binds to key iron-containing enzymes and prevent them from supplying oxygen-containing blood to the tissues. Techniques used to attenuate cyanide in wastewater can broadly be grouped into chemical, physical and biological methods. In recent times, attention has been placed on biotechnological methods, which make use of cyanotrophic microorganisms to clean up cyanide-contaminated environments. This paper reports on studies set out to assess the ability of Phanerochaete chrysosporium to degrade cyanide under different conditions including changes in cyanide concentration, culture mass, time, closed system and open system. At the end of 24-hour contact in an open agitated system with initial pH of 11.5, a control experiment using 100 mg/L cyanide revealed a natural attenuation of 15% with pH decreasing to 9.88, while the best myco-detoxification of 85% was achieved by contacting 100 mg/L cyanide with 0.5 g culture mass, translating into degradation capacity of 17.2 mg/g (milligram of cyanide per gram of culture) with pH reducing to 8.4 in 24 hours. The degradation could be based on a number of mechanisms including hydrolysis to HCN, oxidation to cyanyl radical and cyanate due to natural attenuation through atmospheric contact, and secretion of organic acid, oxidative enzymes, and hydrogen peroxide by the fungus. Keywords: Cyanotrophic Organism, Myco-Detoxification, Cyanide-Laden Effluents, pH |
| Databáze: | OpenAIRE |
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