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Recent Advancements in the Application of Microbial Desalination Cells for Water Desalination, Wastewater Treatment, and Energy Production
Published in Iqbal M. Mujtaba, Thokozani Majozi, Mutiu Kolade Amosa, Water Management, 2018
Adewale Giwa, Vincenzo Naddeo, Shadi W. Hasan
Since MDC technology is still a fairly new approach to desalination, researchers are constantly developing new methods to modify and configure MDCs for better performance and to overcome the technical challenges in conventional MDCs. Currently, about twelve different configurations of MDCs have been developed (Saeed et al., 2015). Conventional MDC uses ferricyanide as a catholyte, and although it exhibits an excellent performance, ferricyanide is considered a toxic and expensive compound. To overcome this problem, an air cathode was designed, where oxygen is the terminal electron acceptor because of its high reduction potential (Kokabian et al., 2013). Oxygen is also more sustainable, because it is abundant in the atmosphere. A more favorable approach is the biocathode, which has proven to be more sustainable and self-generating than the other cathodes used in MDCs. A biocathode uses microorganisms found on the cathode to carry out the reduction reactions in the cathodic chamber.
Cyanide Control in Petroleum Refineries
Published in Bell John W., Proceedings of the 44th Industrial Waste Conference May 9, 10, 11, 1989, 1990
Joseph M. Wong, Patrick M. Maroney
Cyanide toxicity is primarily attributable to HCN.5,6,7 HCN predominates (> 90%) in aqueous solutions at pH < 8.3 and is about two-thirds of the free cyanide at pH 9.O.5 The toxicity of metal-cyanide complexes is largely due to HCN released upon dissociation. Stable cyanide complexes such as ferricyanide and ferrocyanide generally do not produce significant toxicity. However, upon exposure to sunlight or ultraviolet (UV) light, part of the ferrocyanide may dissociate to liberate HCN, which could cause toxicity to fish.2,5 The rate of dissociation depends on exposure to ultraviolet radiation, and is therefore slow in deep, turbid, or shaded waters. Loss of HCN to the atmosphere and the bacterial and chemical destruction that occur at the same time as cyanide production tend to prevent increases of HCN concentrations to harmful levels.5
The Leaching of Palladium from Polymetallic Oxide Ores using Alkaline Ferricyanide Solutions
Published in Mineral Processing and Extractive Metallurgy Review, 2023
Huan Li, Elsayed Oraby, G. A. Bezuidenhout, Jacques Eksteen
Moreover, Zhai, Zhai, and Dong (2009) used ferricyanide to leach Au nanoparticles by releasing free cyanide (Equation 12). In the system, ferricyanide functioned as both an oxidant and a source of free cyanide. However, the behavior of nanoparticles in ferricyanide solution may be different from that of ores in this study. Ferricyanide has been reported as a highly stable complex and is very hard to decompose to release free cyanide unless under certain conditions (highly acidic or reducing environment and/or UV light exposure) (Arellano and Martínez 2010; Ašpergěr 1952; Fernanda Caicedo, Schadach Brum, and Betancourt Buitrago 2020; Yu, Peng, and Wang 2011). Under the conditions of the present study (pH 11 and oxidizing environment), it can be considered that ferric/ferrocyanide was not likely to decompose to an obvious extent.
Silver nanoparticles decorated eggshell membrane as an effective platform for interference free sensing of dopamine
Published in Journal of Environmental Science and Health, Part A, 2018
Sudeshna Datta, Baishali Kanjilal, Priyabrata Sarkar
CV of glassy carbon electrode was performed at different stages of electrode modifications to observe effect of AgNPs on electron transfer. At the onset of the experiment, cyclic voltammetry of ferricyanide was done as it was an effective and convenient method to understand the surface status and the barrier of the modified electrode during each step of modifications. Ferricyanide Fe [(CN)6]3+ is a traditional electro active chemical which is often used as a mediator in various electrochemical sensors. In this work, 5 mM K3Fe (CN) 6/K4Fe (CN)6 in 0.1 M KCl solution was used as a typical system to determine whether the modification on the working electrode blocked or enhanced the diffusion of ferricyanide on the electrode. The bare glassy carbon electrode showed a typical oxidation reduction peak with a good peak separation due to electrochemical reaction of Fe(CN)4−/3−(Fig. 3a). When ESM without nanoparticles was fixed on the working electrode, a remarkable decrease in both the peak heights was observed. This was due to the fact that ESM, being non conducting on its own, had slowed down the electron transfer between the electrolyte and the electrode during the reaction and as a result intensity of redox peaks was decreased. But in the next step when the ESM loaded with AgNPs was used on the working electrode, well defined redox peaks were observed, the amplitude of which were 1.5 times higher than the peaks obtained without nanoparticles. This confirmed that AgNPs had successfully improved the conductivity of working electrode with high surface area. In Fig. 3(b), the results showed that peak intensity increased with scan rate and the plots of anodic (Ipa) and cathodic peak current (Ipc) vs square root of scan rate exhibited a linear relation with high coefficient of 0.997 for both Ipa and Ipc as predicted theoretically for redox species and also established the fact that modified membrane on the electrode did not create any hindrance in the standard diffusion control reaction.