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Review

Recent Developments in the Photocatalytic Treatment of Cyanide Wastewater: An Approach to Remediation and Recovery of Metals

1
Escuela de Ingeniería Química, Universidad del Valle, Calle 13 #100-00. Cali A.A. 25360, Colombia
2
Facultad de Ciencias Químicas, Universidad Autónoma de Nuevo León, San Nicolás de los Garza 64570, Mexico
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Department of Chemical Engineering, Universidad de Cartagena, Sede Piedra de Bolívar, Avenida del Consulado 48-152, Cartagena A.A. 130001, Colombia
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Graduate Programs in Environmental Applied Science and Management, and School of Occupational and Public Health, Ryerson University, 350 Victoria Street, Toronto, ON M5B 2K3, Canada
5
Department of Chemical and Biochemical Engineering, Thompson Engineering Building, Western University, London, ON N6A 5B9, Canada
*
Author to whom correspondence should be addressed.
Processes 2019, 7(4), 225; https://doi.org/10.3390/pr7040225
Received: 6 March 2019 / Revised: 10 April 2019 / Accepted: 15 April 2019 / Published: 20 April 2019
(This article belongs to the Special Issue Application of Advanced Oxidation Processes)
For gold extraction, the most used extraction technique is the Merrill-Crow process, which uses lixiviants as sodium or potassium cyanide for gold leaching at alkaline conditions. The cyanide ion has an affinity not only for gold and silver, but for other metals in the ores, such as Al, Fe, Cu, Ni, Zn, and other toxic metals like Hg, As, Cr, Co, Pb, Sn, and Mn. After the extraction stage, the resulting wastewater is concentrated at alkaline conditions with concentrations up to 1000 ppm of metals. Photocatalysis is an advanced oxidation process (AOP) able to generate a photoreaction in the solid surface of a semiconductor activated by light. Although it is well known that photocatalytic processes can remove metals in solution, there are no compilations about the researches on photocatalytic removal of metals in wastewater with cyanide. Hence, this review comprises the existing applications of photocatalytic processes to remove metal and in some cases recover cyanide from recalcitrant wastewater from gold extraction. The use of this process, in general, requires the addition of several scavengers in order to force the mechanism to a pathway where the electrons can be transferred to the metal-cyanide matrices, or elsewhere the entire metallic cyanocomplex can be degraded by an oxidative pathway. View Full-Text
Keywords: UV-LED; photoreactors; mining wastewater; cyanide; metal removal UV-LED; photoreactors; mining wastewater; cyanide; metal removal
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MDPI and ACS Style

Betancourt-Buitrago, L.A.; Hernandez-Ramirez, A.; Colina-Marquez, J.A.; Bustillo-Lecompte, C.F.; Rehmann, L.; Machuca-Martinez, F. Recent Developments in the Photocatalytic Treatment of Cyanide Wastewater: An Approach to Remediation and Recovery of Metals. Processes 2019, 7, 225. https://doi.org/10.3390/pr7040225

AMA Style

Betancourt-Buitrago LA, Hernandez-Ramirez A, Colina-Marquez JA, Bustillo-Lecompte CF, Rehmann L, Machuca-Martinez F. Recent Developments in the Photocatalytic Treatment of Cyanide Wastewater: An Approach to Remediation and Recovery of Metals. Processes. 2019; 7(4):225. https://doi.org/10.3390/pr7040225

Chicago/Turabian Style

Betancourt-Buitrago, Luis A., Aracely Hernandez-Ramirez, Jose A. Colina-Marquez, Ciro F. Bustillo-Lecompte, Lars Rehmann, and Fiderman Machuca-Martinez. 2019. "Recent Developments in the Photocatalytic Treatment of Cyanide Wastewater: An Approach to Remediation and Recovery of Metals" Processes 7, no. 4: 225. https://doi.org/10.3390/pr7040225

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