文章基本信息

标题：Photocatalytic Advanced Oxidation Processes for Neutralizing Free Cyanide in Gold Processing Effluents in Arequipa, Southern Peru
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作者：David C. Vuono ; Johan Vanneste ; Linda A. Figueroa 等
期刊名称：Sustainability
印刷版ISSN：2071-1050
出版年度：2021
卷号：13
期号：17
页码：9873
DOI：10.3390/su13179873
语种：English
出版社：MDPI, Open Access Journal
摘要：Cyanide (CN−) from gold processing effluents must be removed to protect human health and the environment. Reducing the use of chemical reagents is desirable for small centralized and decentralized facilities. In this work, we aimed to optimize the use of ultraviolet (UV) radiation coupled with hydrogen peroxide (H2O2) to enhance the rate and extent of CN− removal in synthetic and actual gold processing effluents, from one centralized and one decentralized facility in southern Peru. Bench-scale studies conducted using H2O2 and ambient UV showed no significant effects on CN− destruction; however, experiments with higher UV intensity and H2O2 accelerated free CN− degradation. When a 1:1 stoichiometric ratio of CN−:H2O2 was tested, the highly concentrated effluent (1 g CN−/L) had a slower pseudo first-order rate constant (k = 0.0066 min−1) and took ~5 h longer to reach 99% destruction, compared with the low concentration effluent (100 mg CN−/L; k = 0.0306 min−1). Lastly, a TiO2 photocatalyst with low stoichiometric CN−:H2O2 ratios (1:0.1 and 1:0.2), in a compound parabolic solar concentrator, was tested to investigate the degradation of a high concentration effluent (1.28 g CN−/L). These results show a significant improvement to degradation rate within a 20 min period, advancing treatment options for mineral processing facilities.