Effect of the presence of inorganic ions and operational parameters on free cyanide degradation by ultraviolet C activation of persulfate in synthetic mining wastewater

Cyanide is one of the most potent and toxic chemicals produced by industry. The jewellery industry of Córdoba (Spain) generates a wastewater (residue) that contains free cyanide, as well as large amounts of cyano–metal complexes. Cyanide is highly toxic to living systems because it forms very stable complexes with transition metals that are essential for protein function. In spite of its extreme toxicity, some organisms have acquired mechanisms to avoid cyanide poisoning. The biological assimilation of cyanide needs the concurrence of three separate processes: (i) a cyanide-insensitive respiratory chain, (ii) a system for iron acquisition (siderophores) and (iii) a cyanide assimilation pathway. Siderophores are low-molecular-mass compounds (600–1500 Da) that scavenge iron (Fe3+) ions (usually with extremely high affinity) from the environment under iron-limiting conditions. There are two main classes of siderophores: catechol and hydroxamate types. The catechol-type siderophores chelate ferric ion via a hydroxy group, whereas the hydroxamate-type siderophores bind iron via a carbonyl group with the adjacent nitrogen. In the presence of cyanide, bacterial proliferation requires this specific metal uptake system because siderophores are able to break down cyano–metal complexes. Pseudomonas pseudoalcaligenes CECT5344 is able to use free cyanide or cyano–metal complexes as nitrogen source. A proteomic approach was used for the isolation and identification, in this strain, of a protein that was induced in the presence of cyanide, namely CN0, that is involved in siderophore biosynthesis in response to cyanide. An overview of bacterial cyanide degradation pathways and the involvement of siderophores in this process are presented.

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Natural Removal of Cyanide in Gold Milling Effluents - Evaluation of Removal Kinetics

Water Quality Research Journal ◽

10.2166/wqrj.1985.023 ◽

1985 ◽

Vol 20 (2) ◽

pp. 120-135 ◽

Cited By ~ 2

Author(s):

L. Simovic ◽

W.J. Snodgrass

Keyword(s):

Order Reaction ◽

Coefficient Of Determination ◽

Mixed Solution ◽

Free Cyanide ◽

First Order ◽

Model Predictions ◽

Cyanide Degradation ◽

Cyanide Complexes ◽

Cyanide Removal ◽

Cyanide Solutions

Abstract Research using synthetic solutions was conducted to examine factors influencing the natural removal of cyanides from gold mill lagoons. Factors examined included: pH, temperature, ultraviolet irradiation and degree of aeration. Temperature was the principal factor affecting the rate of cyanide loss from solution. UV irradiation had some effect while the effect of aeration was limited. The dominant mechanism for cyanide removal from solution was volatilization. Cyanide degradation was found to follow a first order reaction with respect to free cyanide and metallo-cyanide complexes of Zn, Ni, Cu and Fe. Data from each single metallo-cyanide solution were fitted to a mathematical model which considered volatilization of free cyanide, dissociation of the metallo-cyanide species, and one cyanide complex per metal. The best estimates of the rate constants found for the single metallo-cyanide solutions were used to simulate the removal characteristics of cyanide in a synthetic mixed solution of four metals. The coefficient of determination ranged from 0.93 to 0.99 for model predictions fitted to data from single metallo-cyanide solutions. Estimates for volatilization coefficients varied widely with some of the variation resulting from data which did not completely describe the decay process. The simulation of cyanide removal from the synthetic mixed solution suggested the need to recalibrate the model or to examine the formation of more than one metallo-cyanide species.

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Free Cyanide Degradation Kinetics of Cyanide Degrading Bacteria

ASETH-18,ACABES-18 & EBHSSS-18 Nov. 19-20 2018 Cape Town (South Africa) ◽

10.17758/eares4.eap1118251 ◽

2018 ◽

Keyword(s):

Degradation Kinetics ◽

Free Cyanide ◽

Degrading Bacteria ◽

Cyanide Degradation ◽

Kinetics Of

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Kinetic Study of Cyanide Degradation from Gold mining wastewater Using Photocatalysis

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/844/1/012011 ◽

2020 ◽

Vol 844 ◽

pp. 012011

Author(s):

R.R. Correa-Turizo ◽

R.M. Mestre-Martinez ◽

I Marrugo-Pautt ◽

I Baldiris-Navarro ◽

Carlos Severiche

Keyword(s):

Kinetic Study ◽

Gold Mining ◽

Cyanide Degradation ◽

Mining Wastewater

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Scanning Tunneling Microscopy and Atomic Force Microscopy of Enzymes and Enzyme Complexes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100158418 ◽

1990 ◽

Vol 48 (3) ◽

pp. 174-175

Author(s):

Ronald D. Edstrom ◽

Xiuru Yang ◽

Mary E. Gurnack ◽

Marcia A. Miller ◽

Rui Yang ◽

...

Keyword(s):

Cell Biology ◽

Inorganic Ions ◽

Bulk Liquid ◽

Soluble Form ◽

Scanning Tunneling ◽

Tunneling Microscopy ◽

Metabolic Channeling ◽

Simplistic Notion ◽

Soluble Enzymes

Many of the questions in biochemistry and cell biology are concerned with the relationships of proteins and other macromolecules in complex arrays which are responsible for carrying out metabolic sequences. The simplistic notion that the enzymes we isolate in soluble form from the cytoplasm were also soluble in vivo is being replaced by the concept that these enzymes occur in organized systems within the cell. In this newer view, the cytoplasm is organized and the “soluble enzymes” are in fact fixed in the cellular space and the only soluble components of the cell are small metabolites, inorganic ions etc. Further support for the concept of metabolic organization is provided by the evidence of metabolic channeling. It has been shown that for some metabolic pathways, the intermediates are not in free diffusion equilibrium with the bulk liquid in the cell but are passed along, more or less directly, from one enzyme to the next.

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Electron sources: Past, present, and future

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100149659 ◽

1993 ◽

Vol 51 ◽

pp. 764-765

Author(s):

David C Joy

Keyword(s):

Glass Tube ◽

Source Size ◽

Electron Gun ◽

Operating Parameters ◽

Operational Parameters ◽

Electron Sources ◽

Difficult Decision ◽

Probe Size ◽

Wide Range ◽

Overall Performance

The electron source is the most important component of the Scanning electron microscope (SEM) since it is this which will determine the overall performance of the machine. The gun performance can be described in terms of quantities such as its brightness, its source size, its energy spread, and its stability and, depending on the chosen application, any of these factors may be the most significant one. The task of the electron gun in an SEM is, in fact, particularly difficult because of the very wide range of operational parameters that may be required e.g a variation in probe size of from a few angstroms to a few microns, and a probe current which may go from less than a pico-amp to more than a microamp. This wide range of operating parameters makes the choice of the optimum source for scanning microscopy a difficult decision.Historically, the first step up from the sealed glass tube ‘cathode ray generator’ was the simple, diode, tungsten thermionic emitter.

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IONIC EFFECTS ON THE UPTAKE OF CHLOROMERCURIBENZENE-p-SULPHONIC ACID BY PANCREATIC ISLETS

Acta Endocrinologica ◽

10.1530/acta.0.0860552 ◽

1977 ◽

Vol 86 (3) ◽

pp. 552-560 ◽

Cited By ~ 3

Author(s):

Monica Söderberg ◽

Inge-Bert Täljedal

Keyword(s):

Pancreatic Islets ◽

Islet Cell ◽

Choline Chloride ◽

Inorganic Ions ◽

Sulphonic Acid ◽

Cell Uptake ◽

Β Cells ◽

Sulphydryl Groups ◽

Microdissected Pancreatic Islets ◽

Ionic Effects

ABSTRACT Effects of inorganic ions on the uptake of chloromercuribenzene-p-sulphonic acid (CMBS) were studied in microdissected pancreatic islets of non-inbred ob/ob-mice. Na2SO4 stimulated the total islet cell uptake of CMBS but decreased the amount of CMBS remaining in islets after brief washing with L-cysteine. CaCl2 stimulated both the total and the cysteine-non-displaceable uptake; the stimulatory effect of CaCl2 on the cysteine-non-displaceable CMBS uptake was counteracted by Na2SO4. NaCl, KCl or choline chloride had no significant effect on the total islet cell uptake of CMBS, whereas LiCl was stimulatory. It is concluded that β-cells resemble erythrocytes in having a permeation path for CMBS that is inhibited by SO42−. By analogy with existing models of the erythrocyte membrane, it is suggested that the SO42−-sensitive path leads to sulphydryl groups controlling monovalent cationic permeability in β-cells.

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