The optimization system, which was the subject of our study, is an autonomous chain for the automatic management of cyanide consumption. It is in the phase of industrial automation which made it possible to use the ma...The optimization system, which was the subject of our study, is an autonomous chain for the automatic management of cyanide consumption. It is in the phase of industrial automation which made it possible to use the machines in order to reduce the workload of the worker while keeping a high productivity and a quality in great demand. Furthermore, the use of cyanide in leaching tanks is a necessity in the gold recovery process. This consumption of cyanide must be optimal in these tanks in order to have a good recovery while controlling the concentration of cyanide. Cyanide is one of the most expensive products for mining companies. On a completely different note, we see huge variations during the addition of cyanide. Following a recommendation from the metallurgical and operations teams, the control team carried out an analysis of the problem while proposing a solution to reduce the variability around plus or minus 10% of the addition setpoint through automation. It should be noted that this automatic optimization by monitoring the concentration of cyanide, made use of industrial automation which is a technique which ensures the operation of the ore processing chain without human intervention. In other words, it made it possible to substitute a machine for man. So, this leads us to conduct a study on concentration levels in the real world. The results show that the analysis of the modeling of the cyanide consumption optimization system is an appropriate solution to eradicate failures in the mineral processing chain. The trend curves demonstrate this resolution perfectly.展开更多
Background: Cassava tuber crop is a staple food rich in carbohydrates and utilized in various forms by millions of Nigerians. The storage root of the cassava contains linamarin, a cyanogenic glycoside that is easily h...Background: Cassava tuber crop is a staple food rich in carbohydrates and utilized in various forms by millions of Nigerians. The storage root of the cassava contains linamarin, a cyanogenic glycoside that is easily hydrolyzed to release cyanide salt compounds which is toxic to the nervous system especially the optic nerve, sometimes leading to optic neuropathy and visual impairment. Aim: The aim of this study is to find out the impact of selected processing methods of high-level cyanide in cassava on optic neuropathy in Wistar albino rats. Methodology: Twenty-four Wistar albino rats were fed with different concentration and duration of predetermined high-cyanide content cassava root cultivar which was processed using different processing methods adopted by various communities in Rivers State, Nigeria (for human consumption). A control group of 3 Wistar albino rats was fed with normal “Growth Mesh” meals. The pre and post weights of the animals and the fundoscopic optic nerve status of the rats were evaluated after 30 and 60 days. SPSS Version 25 was employed for descriptive and inferential statistical analyses. A p-value of ≤0.05 was considered statistically significant. Results: The Cassava species available in Rivers State have high cyanide content (2336.79 mg CN<sup>-</sup>/kg dry weight of cassava). There was statistically significant reduction in the cyanide content (p = 0.000) depending on the various common processing methods (into garri for human consumption): 24 hours, 48 hours, fermentation;with and without red palm oil additive. The individual weights as well as the mean weight of the 24 rats in the experimental group increased gradually from the first week to the 9<sup>th</sup> week with a slight weight reduction on the third and fourth weeks which was not statistically significant (p = 0.092). However, there was a steady increase in the weights of the animals in the control group throughout the 9 weeks. Varying degrees of optic neuropathy occurred, worse with the rats that had 24-hour fermented cassava twice daily for 60 days. The intra and inter group differences in the optic disc changes was statistically significant (p = 0.000). Conclusion: Longer duration of processing cassava roots into garri for human consumption reduces its cyanide content and minimizes the adverse impact on the optic nerve.展开更多
Copolymerization of propylene oxide (PO) and ethylene oxide (EO) using double metal cyanide (DMC) complex as the catalyst was carried out. The structure of random copolymers was confirmed by 13C-NMR and IR spectra. 1H...Copolymerization of propylene oxide (PO) and ethylene oxide (EO) using double metal cyanide (DMC) complex as the catalyst was carried out. The structure of random copolymers was confirmed by 13C-NMR and IR spectra. 1H-NMR analysis shows that the EO content in the copolymer is the same as that in the initial monomer feed. Moderate molecular weight copolymers with various EO content were obtained and their values of molecular weight distribution (MWD) fell in the range of 1.21-1.55. It was found that the molecular weight of copolymers is controlled by the mass ratio ofEO + PO to initiator moles used. The reaction rate as well as polymer yield decrease with increasing EO content in the feed composition.展开更多
In order to verify the accuracy of ion chromatography for cyanide detection,optimization conditions were studied,and comparison was made for the detection results of cyanide between titration and isonicotinic acid pyr...In order to verify the accuracy of ion chromatography for cyanide detection,optimization conditions were studied,and comparison was made for the detection results of cyanide between titration and isonicotinic acid pyrazolone spectrophotometry. The results showed that ion chromatography has good linearity and reproducibility,with the recovery rate of 95%-105% and the limit of detection of 0. 001 mg/L. This method is simple,rapid,safe,selective,and suitable for the determination of cyanide in pollution-free livestock product breeding water.展开更多
Cyanide is a toxin and one of the most rapidly acting fatal poisons that human being is aware. If it is not treated promptly, encountering to cyanide poison will lead to die in minutes. Cyanide avoids cellular oxygen ...Cyanide is a toxin and one of the most rapidly acting fatal poisons that human being is aware. If it is not treated promptly, encountering to cyanide poison will lead to die in minutes. Cyanide avoids cellular oxygen usage by inactivating mitochondrial cytochrome oxidase thus inhibits cellular respiration. In this case, we represent a case report describing uncommon cyanide intoxication owing to consumption of a few portion of apricot kernels and its rapid treatment with dicobalt edetate after suspection of cyanide poisoning.展开更多
This paper reviews milestones in antidotal therapies for cyanide(CN) spanning early remedies,current antidotal systems and research towards next generation therapies.CN has been a part of plant defense mechanisms for ...This paper reviews milestones in antidotal therapies for cyanide(CN) spanning early remedies,current antidotal systems and research towards next generation therapies.CN has been a part of plant defense mechanisms for millions of years.It became industrially important in the nineteenth century with the advent of CN assisted gold mining and the use of CN as a pest control agent.The biochemical basis of CN poisoning was actively studied and key mechanisms were understood as early as 1929.These fundamental studies led to a variety of antidotes,including indirect CN binders that generate methemoglobin,direct CN binders such as hydroxocobalamin,and sulfur donors that convert CN to the less toxic thiocyanate.Research on blood gases at the end of the twentieth century shed new light on the role of nitric oxide(NO) in the body.The discovery of NO's ability to compete with CN for enzymatic binding sites provided a previously missed explanation for the rapid efficacy of NO generating antidotes such as the nitrites.Presently used CN therapies include:methemoglobin/NO generators(e.g.,sodium nitrite,amyl nitrite,and dimethyl aminophenol),sulfur donors(e.g.,sodium thiosulfate and glutathione),and direct binding agents [(e.g.,hydroxocobalamin and dicobalt salt of ethylenediaminetetraacetic acid(dicobalt edetate)].A strong effort is being made to explore novel antidotal systems and to formulate them for rapid administration at the point of intoxication in mass casualty scenarios.New antidotes,formulations,and delivery systems are enhancing bioavailability and efficacy and hold promise for a new generation of improved CN countermeasures.展开更多
The interface characteristics of cyanide tailings are different from those of the raw ore. In this study, valuable elements could not be thoroughly recovered via the flotation of cyanide tailings from Shandong, China....The interface characteristics of cyanide tailings are different from those of the raw ore. In this study, valuable elements could not be thoroughly recovered via the flotation of cyanide tailings from Shandong, China. The interface and floatability of these tailings were investig- ated by phase analysis and flotation tests. The chalcopyrite in the cyanide tailings was fine and had a porous surface. The floatability of 68% chalcopyrite was similar to that of galena in the presence of a collector. A layer of fine galena particles compactly wrapped the chalcopyrite. The chalcopyrite recovery sharply decreased as the nonpolar oil residue in cyanide tailings was extracted using alcohol;however, this removal had no effect on the galena. The remaining chalcopyrite in the flotation tailings was covered with an oxidation layer consisting of O, Fe, S, Pb, Cu, Zn, and Si.展开更多
The amount of cyanide in fresh and cooked tuber parenchyma (pulp) of three cultivars of sweet cassava from two local government areas (LGA) of Benue state was studied. Cassava tubers were collected and carefully peele...The amount of cyanide in fresh and cooked tuber parenchyma (pulp) of three cultivars of sweet cassava from two local government areas (LGA) of Benue state was studied. Cassava tubers were collected and carefully peeled to obtain the pulp. The fresh and boiled samples were adequately processed and treated with ninhydrin, Na2CO3 and NaOH and the absorbance of the reaction product measured using UV-Visible spectrometer after construction of a calibration graph using standard cyanide solutions. The amount of cyanide in the fresh pulp varied with differences in cultivars ranging from White Dan-Warri Cultivar: (19.87 to 28.81) mg/kg;Obasanjo cultivar: (17.23 to 28.81) mg/kg and Red Dan-Warri Cultivar (8.23 to 19.31) mg/kg. Also, the cyanide content of cultivars from Oju LGA was generally higher than that of the cultivars from Gwer-east LGA. Cyanide content varied with the period of the day harvested in the order: Afternoon > Evening > Morning for all cultivars. Furthermore, cooking greatly reduced the cyanide content of all the sweet cassava cultivars but boiling was more effective than roasting with the cyanide removal increasing with increase in cooking time. The cyanide content of the tuber parenchyma of the sweet cassava cultivars was very low (<30 mg/kg) which is in agreement with reported values for sweet cassava. However, cooking at a reasonable time interval will further reduce their cyanide levels to further safe limits.展开更多
In this research, adsorption of cyanide onto cata- lyst synthesized with activated carbon and γ- alumina used supported and cooper has been studied by means of batch technique. Percentage adsorption was determined fo...In this research, adsorption of cyanide onto cata- lyst synthesized with activated carbon and γ- alumina used supported and cooper has been studied by means of batch technique. Percentage adsorption was determined for this catalyst in function of pH, adsorbate concentration and temperature. Adsorption data has been interpret- ed in terms of Freundlich and Langmuir equa-tions. Thermodynamics parameters for the ad-sorption system have been determined at three different temperatures.展开更多
AIM: To demonstrate the potential of using 2-aminothiazoline-4-carboxylic acid(ATCA) as a novel biomarker/forensic biomarker for cyanide poisoning. METHODS: A sensitive method was developed and employed for the identi...AIM: To demonstrate the potential of using 2-aminothiazoline-4-carboxylic acid(ATCA) as a novel biomarker/forensic biomarker for cyanide poisoning. METHODS: A sensitive method was developed and employed for the identification and quantification of ATCA in biological samples, where the sample extraction and clean up were achieved by solid phase extraction(SPE). After optimization of SPE procedures, ATCA was analyzed by high performance liquid chromatographytandem mass spectrometry. ATCA levels following the administration of different doses of potassium cyanide(KCN) to mice were measured and compared to endogenous ATCA levels in order to study the significance of using ATCA as a biomarker for cyanide poisoning.RESULTS: A custom made analytical method was established for a new(mice) model when animals were exposed to increasing KCN doses. The application of this method provided important new information on ATCA as a potential cyanide biomarker. ATCA concentration in mice plasma samples were increased from 189 ± 28 ng/mL(n = 3) to 413 ± 66 ng/mL(n = 3) following a 10 mg/kg body weight dose of KCN introduced subcutaneously. The sensitivity of this analytical method proved to be a tool for measuring endogenous level of ATCA in mice organs as follows: 1.2 ± 0.1 μg/g for kidney samples, 1.6 ± 0.1 μg/g for brain samples, 1.8 ± 0.2 μg/g for lung samples, 2.9 ± 0.1 μg/g for heart samples, and 3.6 ± 0.9 μg/g for liver samples. CONCLUSION: This finding suggests that ATCA has the potential to serve as a plasma biomarker / forensic biomarker for cyanide poisoning.展开更多
Cyanidation is the main process for gold and silver recovery from its ores. In this study, a process is proposed to recover copper and cyanide from barren solutions from the Merrill-Crowe cementation process with zinc...Cyanidation is the main process for gold and silver recovery from its ores. In this study, a process is proposed to recover copper and cyanide from barren solutions from the Merrill-Crowe cementation process with zinc dust. This technology is based on inducing nucleated precipitation of copper and silver in a serpentine reactor, using sodium sulfide as the precipitator, and sulfuric acid for pH control. Results show that pH value has a significant effect on copper cyanide removal efficiency, and it was determined the optimal pH range to be 2.5 - 3. At this pH value, the copper cyanide removal efficiency achieved was up to 97 and 99%, when copper concentration in the influent was 636 and 900 ppm. respectively. In this process (sulphidization-acidification-thickening-HCN recycling), the cyanide associated with copper cyanide complexes, is released as HCN gas under weakly acidic conditions, allowing it to be recycled back to the cyanidation process as free cyanide. Cyanide recovery was 90%. Finally, this procedure was successfully run at Minera William in México.展开更多
The importance of gold recovery from low grade ores and flotation tailings is continuously increasing due to raising gold demand and thereby high gold prices. However, due to raising social awareness of the ecological...The importance of gold recovery from low grade ores and flotation tailings is continuously increasing due to raising gold demand and thereby high gold prices. However, due to raising social awareness of the ecological impacts of cyanidic gold extraction and environ-mental specifications, the development and the implementation of alternative hydrometallurgical extraction processes have been a focus for many research institutions in last decades. Present work gives a comparison between compatible extraction reagents, with focus on less harmful processes. The target of this review is to point out the best cyanide-free processes of following methods and reagents: Bioleaching, Chlorination, Aqua Regia, Bromine, Thiocyanate, Thiosulfate and Thiourea leaching. For this propose, the gold leaching reagents are described and discussed in terms of their environmental and economical points of view. As result of this comparison, thiourea stands out as the most promising alternative gold leaching reagent to cyanide.展开更多
Over the past decade the concern about toxic metals in freshwater has increased. Environmental laws such as the Clean Water Act have forced industries that produce metal containing wastewater to treat their wastewater...Over the past decade the concern about toxic metals in freshwater has increased. Environmental laws such as the Clean Water Act have forced industries that produce metal containing wastewater to treat their wastewater prior to discharge. The purpose of this study was to investigate the use of a novel method for the minimization of heavy metals in the wastewater from the mining industry. A very promising electrochemical treatment technique that does not require chemical additions is electrocoagulation (EC) and sulphide precipitation. The present study has been done for the recovery of gold and silver contained in pregnant solution from the cyanidation process using the electrocoagulation technology with iron electrodes;that is a developed alternative technology for the Merril-Crowe process. The average gold and silver content in pregnant solution was 4.27 and 283 ppm respectively and the recoveries were 92% for gold and 95% for silver, with optimum operating parameters of pH 10, residence time of 20 minutes and addition of sodium chloride of 4 gr/L. The results of precipitation process show that the elimination of lead, zinc, cooper and iron ions from the barren solution was successful, with optimum operating parameters of pH 3 and residence time of 15 minutes, and the recoveries were 99% of these ions. Finally the characterization of the solid products of gold and silver formed during the EC process with Scanning Electronic Microscope was performed. Results suggest that magnetite particles and amorphous iron oxyhydroxides (lepidocrocite) were present.展开更多
A stopped-flow reversed flow injection method for the determination of free cyanide is proposed. Pyridine-barbituric acid mixture is injected in the flow system as reagent to form the colour species with cyanide. The ...A stopped-flow reversed flow injection method for the determination of free cyanide is proposed. Pyridine-barbituric acid mixture is injected in the flow system as reagent to form the colour species with cyanide. The flow is stopped when the reagent zone comes in the flow cell, where absorbance-time data are collected at 580nm wavelength. The linear range of the determination is 0.1 -10μg/ml CN-. The sampling rate is 60h-1 and the relative standard deviation is 1.6% (n=16) at 5.0 μg/ml CN-1 level. With satisfactory results, the proposed method was applied to the determination of free cyanide in wastewater without sample pretreatment.展开更多
The samples of 25 nL of chloride and cyanide were determined with a kind of glass capillary indicating electrodes by potentiometry. Silver was deposited by the silvermirror reaction on the inner surface of the glass c...The samples of 25 nL of chloride and cyanide were determined with a kind of glass capillary indicating electrodes by potentiometry. Silver was deposited by the silvermirror reaction on the inner surface of the glass capillary with a volume of 25 nL. The AgCl film and the AgI film were formed by the treatment of the capillary with a FeCl 3 solution and further with a KI solution. The samples were collected automatically into the capillary by the capillary ascension. The procedure in the measurement was merely to place a reference electrode and a capillary indicating electrode vertically on a strip filter paper containing a 01 mol/L NaNO 3 solution. The various i.d. of the capillary electrodes were used to determine samples ranging from 25 nL to dozens of microliters. The ranges of the linear response to chloride and cyanide were 32×10 -4 —22×10 -1 mol/L and 10×10 -5 —10×10 -1 mol/L with an average slope of 552 and 52—62 mV/decade , respectively. The samples with various concentrations of chloride and cyanide were determined, and the relative standard deviations were less than 7%.展开更多
The synthesis, structure and characterization of a new one-dimensional cyanide-bridgedcomplex [Ni（pn）2Ni（CN）4]n’nH2O （where pn = 1,2-diaminopropane） are described. The structure ofthis complex consists of a one...The synthesis, structure and characterization of a new one-dimensional cyanide-bridgedcomplex [Ni（pn）2Ni（CN）4]n’nH2O （where pn = 1,2-diaminopropane） are described. The structure ofthis complex consists of a one-dimensional polymeric chain-Ni（pn）2-NC-Ni（CN）2-CN-Ni（pn）2- inwhich the Ni（II） centers are linked by two CN groups.展开更多
Thirty-two mongrel dogs were divided into 4 groups.24 dogs of the 3 therapeutic groupswere inflicted with mild,medium,and severe hemorrhage through right femoral artery bleeding untilthe arterial systolic pressure dro...Thirty-two mongrel dogs were divided into 4 groups.24 dogs of the 3 therapeutic groupswere inflicted with mild,medium,and severe hemorrhage through right femoral artery bleeding untilthe arterial systolic pressure dropped to 9.33,6.67 and 5.33 kPa,respectively,and then intoxicatedby intravenous NaCN 2.5mg/kg 3min after intoxication,intravenous 4-dimethylaminophenol(DMAP) 2 mg/kg was given.8 dogs of the control were inflicted with mild hemorrhage and similar-ly intoxicated,but no treatment was given.The changes of hemodynamics,blood gases andmethemoglobin were observed in the dogs.It was found that all the dogs of the control died with-in 5 min after administration of NaCN.DMAP could exert an excitatory effect on hemodynamicsand rescue the animals from death.The excitatory effect of DMAP became weaker whilehemorrhage became more severe.DMAP could further disturb the oxygen-caring capacity ofhemoglobin because of the formation of large amounts of methemoglobin when it was used as an anti-dote for cyanide intoxidation accompanied with acute hemorrhage.展开更多
The reaction of tricyanometallate precursor, Bu_4N[Fe(Tp)(CN)_3] and(Bu_4N)[(pzTp)Fe(CN)_3](Tp = tris(pyrazolyl)hydroborate, pzTp = tetrakis(pyrazolyl)borate) with Ni(ClO_4).26 H_2O in the presence of the monodentate ...The reaction of tricyanometallate precursor, Bu_4N[Fe(Tp)(CN)_3] and(Bu_4N)[(pzTp)Fe(CN)_3](Tp = tris(pyrazolyl)hydroborate, pzTp = tetrakis(pyrazolyl)borate) with Ni(ClO_4).26 H_2O in the presence of the monodentate N-methylimidazole ligand afforded two new cyano-bridged heterobimetallic {Fe2 Ni} trinuclear clusters, {[Fe(Tp)(CN)_3]_2[Ni(Mim)_4]}·8 H_2O(1) and {[Fe(pzTp)(CN)_3]_2[Ni(Mim)_4]}·2 CH_3OH·2H_2O(2). The molecular structure was determined by single-crystal X-ray diffraction. In the two compounds, the FeIII ions were coordinated by three cyanide carbon atoms and three nitrogen atoms of Tp(or pzTp) anions, whereas, the NiII ions were surrounded by two cyanide nitrogen atoms and four nitrogen atoms from four monodentate N-methylimidazole ligands, and they were bridged by tricyanometalate building block to form similar {Fe2Ni} trinuclear clusters. Cyclic voltammetry(CV) measurements indicated that compound 1 exhibited two quasireversible iron-centered reduction processes at –0.71 and –0.17 V and one quasireversible nickel-centered oxidation process at 0.92 V, while compound 2 showed two quasireversible iron-centered reduction processes at –0.66 and –0.09 V and one quasireversible nickel-centered oxidation process at 0.88 V. Magnetic measurements showed that compounds 1 and 2 exhibited strong intrachain ferromagnetic interaction between the low-spin Fe~Ⅲ(S = 1/2) and high-spin Ni~Ⅱ(S = 1) ions.展开更多
Convenient. efficient one-pot synthesis of ferrocenylcyanide, which is a very important intermediate in synthesis of chiral ferrocenyl ligands in asymmetric catalysis. is described. The chemical yield is up to 60%.
文摘The optimization system, which was the subject of our study, is an autonomous chain for the automatic management of cyanide consumption. It is in the phase of industrial automation which made it possible to use the machines in order to reduce the workload of the worker while keeping a high productivity and a quality in great demand. Furthermore, the use of cyanide in leaching tanks is a necessity in the gold recovery process. This consumption of cyanide must be optimal in these tanks in order to have a good recovery while controlling the concentration of cyanide. Cyanide is one of the most expensive products for mining companies. On a completely different note, we see huge variations during the addition of cyanide. Following a recommendation from the metallurgical and operations teams, the control team carried out an analysis of the problem while proposing a solution to reduce the variability around plus or minus 10% of the addition setpoint through automation. It should be noted that this automatic optimization by monitoring the concentration of cyanide, made use of industrial automation which is a technique which ensures the operation of the ore processing chain without human intervention. In other words, it made it possible to substitute a machine for man. So, this leads us to conduct a study on concentration levels in the real world. The results show that the analysis of the modeling of the cyanide consumption optimization system is an appropriate solution to eradicate failures in the mineral processing chain. The trend curves demonstrate this resolution perfectly.
文摘Background: Cassava tuber crop is a staple food rich in carbohydrates and utilized in various forms by millions of Nigerians. The storage root of the cassava contains linamarin, a cyanogenic glycoside that is easily hydrolyzed to release cyanide salt compounds which is toxic to the nervous system especially the optic nerve, sometimes leading to optic neuropathy and visual impairment. Aim: The aim of this study is to find out the impact of selected processing methods of high-level cyanide in cassava on optic neuropathy in Wistar albino rats. Methodology: Twenty-four Wistar albino rats were fed with different concentration and duration of predetermined high-cyanide content cassava root cultivar which was processed using different processing methods adopted by various communities in Rivers State, Nigeria (for human consumption). A control group of 3 Wistar albino rats was fed with normal “Growth Mesh” meals. The pre and post weights of the animals and the fundoscopic optic nerve status of the rats were evaluated after 30 and 60 days. SPSS Version 25 was employed for descriptive and inferential statistical analyses. A p-value of ≤0.05 was considered statistically significant. Results: The Cassava species available in Rivers State have high cyanide content (2336.79 mg CN<sup>-</sup>/kg dry weight of cassava). There was statistically significant reduction in the cyanide content (p = 0.000) depending on the various common processing methods (into garri for human consumption): 24 hours, 48 hours, fermentation;with and without red palm oil additive. The individual weights as well as the mean weight of the 24 rats in the experimental group increased gradually from the first week to the 9<sup>th</sup> week with a slight weight reduction on the third and fourth weeks which was not statistically significant (p = 0.092). However, there was a steady increase in the weights of the animals in the control group throughout the 9 weeks. Varying degrees of optic neuropathy occurred, worse with the rats that had 24-hour fermented cassava twice daily for 60 days. The intra and inter group differences in the optic disc changes was statistically significant (p = 0.000). Conclusion: Longer duration of processing cassava roots into garri for human consumption reduces its cyanide content and minimizes the adverse impact on the optic nerve.
文摘Copolymerization of propylene oxide (PO) and ethylene oxide (EO) using double metal cyanide (DMC) complex as the catalyst was carried out. The structure of random copolymers was confirmed by 13C-NMR and IR spectra. 1H-NMR analysis shows that the EO content in the copolymer is the same as that in the initial monomer feed. Moderate molecular weight copolymers with various EO content were obtained and their values of molecular weight distribution (MWD) fell in the range of 1.21-1.55. It was found that the molecular weight of copolymers is controlled by the mass ratio ofEO + PO to initiator moles used. The reaction rate as well as polymer yield decrease with increasing EO content in the feed composition.
文摘In order to verify the accuracy of ion chromatography for cyanide detection,optimization conditions were studied,and comparison was made for the detection results of cyanide between titration and isonicotinic acid pyrazolone spectrophotometry. The results showed that ion chromatography has good linearity and reproducibility,with the recovery rate of 95%-105% and the limit of detection of 0. 001 mg/L. This method is simple,rapid,safe,selective,and suitable for the determination of cyanide in pollution-free livestock product breeding water.
文摘Cyanide is a toxin and one of the most rapidly acting fatal poisons that human being is aware. If it is not treated promptly, encountering to cyanide poison will lead to die in minutes. Cyanide avoids cellular oxygen usage by inactivating mitochondrial cytochrome oxidase thus inhibits cellular respiration. In this case, we represent a case report describing uncommon cyanide intoxication owing to consumption of a few portion of apricot kernels and its rapid treatment with dicobalt edetate after suspection of cyanide poisoning.
基金Robert A.Welch Foundation(x-0011)at Sam Houston State University
文摘This paper reviews milestones in antidotal therapies for cyanide(CN) spanning early remedies,current antidotal systems and research towards next generation therapies.CN has been a part of plant defense mechanisms for millions of years.It became industrially important in the nineteenth century with the advent of CN assisted gold mining and the use of CN as a pest control agent.The biochemical basis of CN poisoning was actively studied and key mechanisms were understood as early as 1929.These fundamental studies led to a variety of antidotes,including indirect CN binders that generate methemoglobin,direct CN binders such as hydroxocobalamin,and sulfur donors that convert CN to the less toxic thiocyanate.Research on blood gases at the end of the twentieth century shed new light on the role of nitric oxide(NO) in the body.The discovery of NO's ability to compete with CN for enzymatic binding sites provided a previously missed explanation for the rapid efficacy of NO generating antidotes such as the nitrites.Presently used CN therapies include:methemoglobin/NO generators(e.g.,sodium nitrite,amyl nitrite,and dimethyl aminophenol),sulfur donors(e.g.,sodium thiosulfate and glutathione),and direct binding agents [(e.g.,hydroxocobalamin and dicobalt salt of ethylenediaminetetraacetic acid(dicobalt edetate)].A strong effort is being made to explore novel antidotal systems and to formulate them for rapid administration at the point of intoxication in mass casualty scenarios.New antidotes,formulations,and delivery systems are enhancing bioavailability and efficacy and hold promise for a new generation of improved CN countermeasures.
基金the National Key R&D Program of China(Nos.2018YFC1902002 and 2018YFC1902003)the Special Fund for the National Natur-al Science Foundation of China(No.U1608254)the En-terprise Research Program(No.2014-0-1-02129).
文摘The interface characteristics of cyanide tailings are different from those of the raw ore. In this study, valuable elements could not be thoroughly recovered via the flotation of cyanide tailings from Shandong, China. The interface and floatability of these tailings were investig- ated by phase analysis and flotation tests. The chalcopyrite in the cyanide tailings was fine and had a porous surface. The floatability of 68% chalcopyrite was similar to that of galena in the presence of a collector. A layer of fine galena particles compactly wrapped the chalcopyrite. The chalcopyrite recovery sharply decreased as the nonpolar oil residue in cyanide tailings was extracted using alcohol;however, this removal had no effect on the galena. The remaining chalcopyrite in the flotation tailings was covered with an oxidation layer consisting of O, Fe, S, Pb, Cu, Zn, and Si.
文摘The amount of cyanide in fresh and cooked tuber parenchyma (pulp) of three cultivars of sweet cassava from two local government areas (LGA) of Benue state was studied. Cassava tubers were collected and carefully peeled to obtain the pulp. The fresh and boiled samples were adequately processed and treated with ninhydrin, Na2CO3 and NaOH and the absorbance of the reaction product measured using UV-Visible spectrometer after construction of a calibration graph using standard cyanide solutions. The amount of cyanide in the fresh pulp varied with differences in cultivars ranging from White Dan-Warri Cultivar: (19.87 to 28.81) mg/kg;Obasanjo cultivar: (17.23 to 28.81) mg/kg and Red Dan-Warri Cultivar (8.23 to 19.31) mg/kg. Also, the cyanide content of cultivars from Oju LGA was generally higher than that of the cultivars from Gwer-east LGA. Cyanide content varied with the period of the day harvested in the order: Afternoon > Evening > Morning for all cultivars. Furthermore, cooking greatly reduced the cyanide content of all the sweet cassava cultivars but boiling was more effective than roasting with the cyanide removal increasing with increase in cooking time. The cyanide content of the tuber parenchyma of the sweet cassava cultivars was very low (<30 mg/kg) which is in agreement with reported values for sweet cassava. However, cooking at a reasonable time interval will further reduce their cyanide levels to further safe limits.
文摘In this research, adsorption of cyanide onto cata- lyst synthesized with activated carbon and γ- alumina used supported and cooper has been studied by means of batch technique. Percentage adsorption was determined for this catalyst in function of pH, adsorbate concentration and temperature. Adsorption data has been interpret- ed in terms of Freundlich and Langmuir equa-tions. Thermodynamics parameters for the ad-sorption system have been determined at three different temperatures.
基金Supported by NIH:NIAID/USAMRICD Interagency Agreements(W911NF-07-D-0001)the USAMRICD under the auspices of the US Army Research Office Scientific Services Program administered by Battelle(Delivery order 0557,Contract No TCN 08284)the Robert A.Welch Foundation at Sam Houston State University,Huntsville,TX,United States
文摘AIM: To demonstrate the potential of using 2-aminothiazoline-4-carboxylic acid(ATCA) as a novel biomarker/forensic biomarker for cyanide poisoning. METHODS: A sensitive method was developed and employed for the identification and quantification of ATCA in biological samples, where the sample extraction and clean up were achieved by solid phase extraction(SPE). After optimization of SPE procedures, ATCA was analyzed by high performance liquid chromatographytandem mass spectrometry. ATCA levels following the administration of different doses of potassium cyanide(KCN) to mice were measured and compared to endogenous ATCA levels in order to study the significance of using ATCA as a biomarker for cyanide poisoning.RESULTS: A custom made analytical method was established for a new(mice) model when animals were exposed to increasing KCN doses. The application of this method provided important new information on ATCA as a potential cyanide biomarker. ATCA concentration in mice plasma samples were increased from 189 ± 28 ng/mL(n = 3) to 413 ± 66 ng/mL(n = 3) following a 10 mg/kg body weight dose of KCN introduced subcutaneously. The sensitivity of this analytical method proved to be a tool for measuring endogenous level of ATCA in mice organs as follows: 1.2 ± 0.1 μg/g for kidney samples, 1.6 ± 0.1 μg/g for brain samples, 1.8 ± 0.2 μg/g for lung samples, 2.9 ± 0.1 μg/g for heart samples, and 3.6 ± 0.9 μg/g for liver samples. CONCLUSION: This finding suggests that ATCA has the potential to serve as a plasma biomarker / forensic biomarker for cyanide poisoning.
文摘Cyanidation is the main process for gold and silver recovery from its ores. In this study, a process is proposed to recover copper and cyanide from barren solutions from the Merrill-Crowe cementation process with zinc dust. This technology is based on inducing nucleated precipitation of copper and silver in a serpentine reactor, using sodium sulfide as the precipitator, and sulfuric acid for pH control. Results show that pH value has a significant effect on copper cyanide removal efficiency, and it was determined the optimal pH range to be 2.5 - 3. At this pH value, the copper cyanide removal efficiency achieved was up to 97 and 99%, when copper concentration in the influent was 636 and 900 ppm. respectively. In this process (sulphidization-acidification-thickening-HCN recycling), the cyanide associated with copper cyanide complexes, is released as HCN gas under weakly acidic conditions, allowing it to be recycled back to the cyanidation process as free cyanide. Cyanide recovery was 90%. Finally, this procedure was successfully run at Minera William in México.
文摘The importance of gold recovery from low grade ores and flotation tailings is continuously increasing due to raising gold demand and thereby high gold prices. However, due to raising social awareness of the ecological impacts of cyanidic gold extraction and environ-mental specifications, the development and the implementation of alternative hydrometallurgical extraction processes have been a focus for many research institutions in last decades. Present work gives a comparison between compatible extraction reagents, with focus on less harmful processes. The target of this review is to point out the best cyanide-free processes of following methods and reagents: Bioleaching, Chlorination, Aqua Regia, Bromine, Thiocyanate, Thiosulfate and Thiourea leaching. For this propose, the gold leaching reagents are described and discussed in terms of their environmental and economical points of view. As result of this comparison, thiourea stands out as the most promising alternative gold leaching reagent to cyanide.
文摘Over the past decade the concern about toxic metals in freshwater has increased. Environmental laws such as the Clean Water Act have forced industries that produce metal containing wastewater to treat their wastewater prior to discharge. The purpose of this study was to investigate the use of a novel method for the minimization of heavy metals in the wastewater from the mining industry. A very promising electrochemical treatment technique that does not require chemical additions is electrocoagulation (EC) and sulphide precipitation. The present study has been done for the recovery of gold and silver contained in pregnant solution from the cyanidation process using the electrocoagulation technology with iron electrodes;that is a developed alternative technology for the Merril-Crowe process. The average gold and silver content in pregnant solution was 4.27 and 283 ppm respectively and the recoveries were 92% for gold and 95% for silver, with optimum operating parameters of pH 10, residence time of 20 minutes and addition of sodium chloride of 4 gr/L. The results of precipitation process show that the elimination of lead, zinc, cooper and iron ions from the barren solution was successful, with optimum operating parameters of pH 3 and residence time of 15 minutes, and the recoveries were 99% of these ions. Finally the characterization of the solid products of gold and silver formed during the EC process with Scanning Electronic Microscope was performed. Results suggest that magnetite particles and amorphous iron oxyhydroxides (lepidocrocite) were present.
基金This study was supported by the National Natural Science Foundation of China
文摘A stopped-flow reversed flow injection method for the determination of free cyanide is proposed. Pyridine-barbituric acid mixture is injected in the flow system as reagent to form the colour species with cyanide. The flow is stopped when the reagent zone comes in the flow cell, where absorbance-time data are collected at 580nm wavelength. The linear range of the determination is 0.1 -10μg/ml CN-. The sampling rate is 60h-1 and the relative standard deviation is 1.6% (n=16) at 5.0 μg/ml CN-1 level. With satisfactory results, the proposed method was applied to the determination of free cyanide in wastewater without sample pretreatment.
基金Supported by the National Natural Science Foundation of China(No.2 9835110) .
文摘The samples of 25 nL of chloride and cyanide were determined with a kind of glass capillary indicating electrodes by potentiometry. Silver was deposited by the silvermirror reaction on the inner surface of the glass capillary with a volume of 25 nL. The AgCl film and the AgI film were formed by the treatment of the capillary with a FeCl 3 solution and further with a KI solution. The samples were collected automatically into the capillary by the capillary ascension. The procedure in the measurement was merely to place a reference electrode and a capillary indicating electrode vertically on a strip filter paper containing a 01 mol/L NaNO 3 solution. The various i.d. of the capillary electrodes were used to determine samples ranging from 25 nL to dozens of microliters. The ranges of the linear response to chloride and cyanide were 32×10 -4 —22×10 -1 mol/L and 10×10 -5 —10×10 -1 mol/L with an average slope of 552 and 52—62 mV/decade , respectively. The samples with various concentrations of chloride and cyanide were determined, and the relative standard deviations were less than 7%.
文摘The synthesis, structure and characterization of a new one-dimensional cyanide-bridgedcomplex [Ni（pn）2Ni（CN）4]n’nH2O （where pn = 1,2-diaminopropane） are described. The structure ofthis complex consists of a one-dimensional polymeric chain-Ni（pn）2-NC-Ni（CN）2-CN-Ni（pn）2- inwhich the Ni（II） centers are linked by two CN groups.
文摘Thirty-two mongrel dogs were divided into 4 groups.24 dogs of the 3 therapeutic groupswere inflicted with mild,medium,and severe hemorrhage through right femoral artery bleeding untilthe arterial systolic pressure dropped to 9.33,6.67 and 5.33 kPa,respectively,and then intoxicatedby intravenous NaCN 2.5mg/kg 3min after intoxication,intravenous 4-dimethylaminophenol(DMAP) 2 mg/kg was given.8 dogs of the control were inflicted with mild hemorrhage and similar-ly intoxicated,but no treatment was given.The changes of hemodynamics,blood gases andmethemoglobin were observed in the dogs.It was found that all the dogs of the control died with-in 5 min after administration of NaCN.DMAP could exert an excitatory effect on hemodynamicsand rescue the animals from death.The excitatory effect of DMAP became weaker whilehemorrhage became more severe.DMAP could further disturb the oxygen-caring capacity ofhemoglobin because of the formation of large amounts of methemoglobin when it was used as an anti-dote for cyanide intoxidation accompanied with acute hemorrhage.
基金partly supported by the NNSFC(Nos.21301023,21501021,11474045)the 2014 Program for Liaoning Excellent Talents in University(No.LJQ2014138)+2 种基金the Program for Dalian Excellent Talents(No.2017RQ148)the Fundamental Research Funds for the Central Universities(wd01157)the 2017 Training Program of Innovation and Entrepreneurship for Undergraduates in Dalian Minzu University(201712026150 and 201812026150)
文摘The reaction of tricyanometallate precursor, Bu_4N[Fe(Tp)(CN)_3] and(Bu_4N)[(pzTp)Fe(CN)_3](Tp = tris(pyrazolyl)hydroborate, pzTp = tetrakis(pyrazolyl)borate) with Ni(ClO_4).26 H_2O in the presence of the monodentate N-methylimidazole ligand afforded two new cyano-bridged heterobimetallic {Fe2 Ni} trinuclear clusters, {[Fe(Tp)(CN)_3]_2[Ni(Mim)_4]}·8 H_2O(1) and {[Fe(pzTp)(CN)_3]_2[Ni(Mim)_4]}·2 CH_3OH·2H_2O(2). The molecular structure was determined by single-crystal X-ray diffraction. In the two compounds, the FeIII ions were coordinated by three cyanide carbon atoms and three nitrogen atoms of Tp(or pzTp) anions, whereas, the NiII ions were surrounded by two cyanide nitrogen atoms and four nitrogen atoms from four monodentate N-methylimidazole ligands, and they were bridged by tricyanometalate building block to form similar {Fe2Ni} trinuclear clusters. Cyclic voltammetry(CV) measurements indicated that compound 1 exhibited two quasireversible iron-centered reduction processes at –0.71 and –0.17 V and one quasireversible nickel-centered oxidation process at 0.92 V, while compound 2 showed two quasireversible iron-centered reduction processes at –0.66 and –0.09 V and one quasireversible nickel-centered oxidation process at 0.88 V. Magnetic measurements showed that compounds 1 and 2 exhibited strong intrachain ferromagnetic interaction between the low-spin Fe~Ⅲ(S = 1/2) and high-spin Ni~Ⅱ(S = 1) ions.
文摘Convenient. efficient one-pot synthesis of ferrocenylcyanide, which is a very important intermediate in synthesis of chiral ferrocenyl ligands in asymmetric catalysis. is described. The chemical yield is up to 60%.
