The Experts below are selected from a list of 300 Experts worldwide ranked by ideXlab platform
Toshihiko Imato - One of the best experts on this subject based on the ideXlab platform.
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Continuous monitoring for Cyanide in waste water with a galvanic hydrogen Cyanide sensor using a purge system
Talanta, 1999Co-Authors: Hitoshi Hachiya, Yoshito Fushinuki, Takashi Masadome, Satoshi Ito, Yasukazu Asano, Toshihiko ImatoAbstract:A continuous monitoring system for Cyanide with a galvanic hydrogen Cyanide sensor and an aeration pump for purging was developed. Hydrogen Cyanide evolved from Cyanide solution using a purging pump was measured with the hydrogen Cyanide sensor. The system showed good performance in terms of stability and selectivity. A linear calibration curve was obtained in the concentrating range from 0 to 15 mg dm3of Cyanide ion with a slope of - 0.24 μA mg-1dm-3. The lower detection limit was 0.1 mg dm-3. The 90% response time of the sensor system was within 3.5 min for a 0.5 mg dm-3Cyanide solution, when the flow rate of the purging air was 1 dm3min-1. The system maintained the initial performance for 6 months in the field test. The developed galvanic sensor system was not subject to interference from sulfide and residual chlorine, compared with a potentiometric sensor system developed previously. The analytical results obtained by the present system were in good agreement with those obtained by the pyridine pyrazolone method. The correlation factor and regression line between both methods were 0.979 and Y = 2.30 x 10-4+ 1.12X, respectively. This system was successfully applied for a continuous monitoring of Cyanide ion in waste water.
Dirk Freese - One of the best experts on this subject based on the ideXlab platform.
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Uptake of ferroCyanide in willow and poplar trees in a long term greenhouse experiment
Ecotoxicology, 2015Co-Authors: Tsvetelina Dimitrova, Frank Repmann, Thomas Raab, Dirk FreeseAbstract:Phytoremediation of sites contaminated with iron Cyanides can be performed using poplar and willow trees. Poplar and willow trees were grown in potting substrate spiked with ferroCyanide concentrations of up to 2,000 mg kg^−1 for 4 and 8 weeks respectively. Soil solution and leaf tissue of different age were sampled for total Cyanide analysis every week. Chlorophyll content in the leaves was determined to quantify Cyanide toxicity. Results showed that Cyanide in the soil solution of spiked soils differed between treatments and on weekly basis and ranged from 0.5 to 1,200 mg l^−1. The maximum Cyanide content in willow and poplar leaves was 518 mg kg^−1 fresh weight (FW) and 148 mg kg^−1 FW respectively. Cyanide accumulated in the leaves increased linearly with increasing Cyanide concentration in the soil solution. On the long term, significantly more Cyanide was accumulated in old leaf tissue than in young tissue. Chlorophyll content in poplar decreased linearly with increasing Cyanide in the soil solution and in leaf tissue, and over time. The inhibitory concentration (IC_50) value for poplars after 4 weeks of exposure was 173 mg l^−1 and for willow after 8 weeks of exposure—768 mg l^−1. Results show that willows tolerate much more Cyanide and over a longer period than poplars, making them very appropriate for remediating sites highly contaminated with iron Cyanides.
David Dreisinger - One of the best experts on this subject based on the ideXlab platform.
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A Review on Recovery of Copper and Cyanide From Waste Cyanide Solutions
Mineral Processing and Extractive Metallurgy Review, 2013Co-Authors: David Dreisinger, Fiona M DoyleAbstract:The mainstream technology for leaching gold from gold ore is still leaching in aqueous alkaline Cyanide solution. However, when copper minerals are present in the gold ore, high levels of free Cyanide must be maintained during leaching because many common copper minerals react with Cyanide, forming copper Cyanide complexes that deplete the solution of free Cyanide. This results in a significant economical penalty through excessive Cyanide consumption and loss of valuable copper in tails. Environmental constraints controlling the discharge of Cyanide from mining industry are being tightened by local governments worldwide. The solution chemistry of copper in Cyanide solution and various technologies for the recovery of copper and Cyanide from barren gold Cyanide solutions were reviewed in the paper. Direct recovery methods are mainly based on the acidification–volatilization–reneutralization (AVR) process or its modifications. These processes are not very efficient for treating low Cyanide solutions and hig...
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studies on solvent extraction of copper and Cyanide from waste Cyanide solution
Journal of Hazardous Materials, 2009Co-Authors: David DreisingerAbstract:Abstract The recovery of copper and Cyanide from waste Cyanide solution with the guanidine extractant (LIX 7950) and the modified amine extractant (LIX 7820) has been investigated. Copper can be effectively extracted from alkaline Cyanide solutions by both extractants. The free Cyanide remains in the aqueous phase due to the preferential extraction of Cu(CN)32− over Cu(CN)43− and CN− by the extractants. The selectivity of the metals with the extractants under different Cyanide levels has been examined. High Cyanide levels tend to depress extraction of copper and silver Cyanides, but exhibit insignificant effect on extraction of gold, zinc, nickel and iron Cyanides. A possible solution to the separation of copper Cyanides and free Cyanide in Cyanide effluents has been suggested, by which copper can be concentrated into a small volume of solution and the barren Cyanide solution recycled to the cyanidation process.
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copper solvent extraction from waste Cyanide solution with lix 7820
Solvent Extraction and Ion Exchange, 2009Co-Authors: David DreisingerAbstract:The use of a solvent mixture of a quaternary amine and nonylphenol (LIX 7820) to extract copper Cyanide from waste Cyanide solution has been studied. Copper extraction is favorable at low pH, whereas a high Cyanide‐to‐copper ratio tends to suppress copper loading. The preferential extraction of Cu(CN)3 2− over Cu(CN)4 3− and CN− has been confirmed by the examination of both the extraction of copper and Cyanide by the solvent mixture under different experimental conditions. The solvent mixture also strongly extracted zinc and nickel from the Cyanide solution, but it exhibits weak affinity for iron Cyanide complex and free Cyanide. The important findings suggested the potential application of the solvent mixture for the recovery of copper and Cyanide from waste Cyanide solutions, by which copper can be extracted and concentrated into a small volume of solution and the barren Cyanide solution recycled to the cyanidation process.
Tim Mansfeldt - One of the best experts on this subject based on the ideXlab platform.
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long term ferroCyanide application via deicing salts promotes the establishment of actinomycetales assimilating ferroCyanide derived carbon in soil
Microbial Biotechnology, 2016Co-Authors: Silvia Gschwendtner, Tim Mansfeldt, Evangelia Touliari, Franz Buegger, Susanne Kublik, Michael SchloterAbstract:Summary Cyanides are highly toxic and produced by various microorganisms as defence strategy or to increase their competitiveness. As degradation is the most efficient way of detoxification, some microbes developed the capability to use Cyanides as carbon and nitrogen source. However, it is not clear if this potential also helps to lower Cyanide concentrations in roadside soils where deicing salt application leads to significant inputs of ferroCyanide. The question remains if biodegradation in soils can occur without previous photolysis. By conducting a microcosm experiment using soils with/without pre-exposition to road salts spiked with 13C-labelled ferroCyanide, we were able to confirm biodegradation and in parallel to identify bacteria using ferroCyanide as C source via DNA stable isotope probing (DNA-SIP), TRFLP fingerprinting and pyrosequencing. Bacteria assimilating 13C were highly similar in the pre-exposed soils, belonging mostly to Actinomycetales (Kineosporia, Mycobacterium, Micromonosporaceae). In the soil without pre-exposition, bacteria belonging to Acidobacteria (Gp3, Gp4, Gp6), Gemmatimonadetes (Gemmatimonas) and Gammaproteobacteria (Thermomonas, Xanthomonadaceae) used ferroCyanide as C source but not the present Actinomycetales. This indicated that (i) various bacteria are able to assimilate ferroCyanide-derived C and (ii) long-term exposition to ferroCyanide applied with deicing salts leads to Actinomycetales outcompeting other microorganisms for the use of ferroCyanide as C source.
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Long‐term ferroCyanide application via deicing salts promotes the establishment of Actinomycetales assimilating ferroCyanide‐derived carbon in soil
Microbial Biotechnology, 2016Co-Authors: Silvia Gschwendtner, Tim Mansfeldt, Evangelia Touliari, Franz Buegger, Susanne Kublik, Michael SchloterAbstract:Summary Cyanides are highly toxic and produced by various microorganisms as defence strategy or to increase their competitiveness. As degradation is the most efficient way of detoxification, some microbes developed the capability to use Cyanides as carbon and nitrogen source. However, it is not clear if this potential also helps to lower Cyanide concentrations in roadside soils where deicing salt application leads to significant inputs of ferroCyanide. The question remains if biodegradation in soils can occur without previous photolysis. By conducting a microcosm experiment using soils with/without pre-exposition to road salts spiked with 13C-labelled ferroCyanide, we were able to confirm biodegradation and in parallel to identify bacteria using ferroCyanide as C source via DNA stable isotope probing (DNA-SIP), TRFLP fingerprinting and pyrosequencing. Bacteria assimilating 13C were highly similar in the pre-exposed soils, belonging mostly to Actinomycetales (Kineosporia, Mycobacterium, Micromonosporaceae). In the soil without pre-exposition, bacteria belonging to Acidobacteria (Gp3, Gp4, Gp6), Gemmatimonadetes (Gemmatimonas) and Gammaproteobacteria (Thermomonas, Xanthomonadaceae) used ferroCyanide as C source but not the present Actinomycetales. This indicated that (i) various bacteria are able to assimilate ferroCyanide-derived C and (ii) long-term exposition to ferroCyanide applied with deicing salts leads to Actinomycetales outcompeting other microorganisms for the use of ferroCyanide as C source.
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Charakterisierung von Cyaniden in Böden und industriellen Abfällen mit der Fourier-Transformations-Infrarot-Spektrometrie
Umweltwissenschaften und Schadstoff-Forschung, 2002Co-Authors: Birgit Jannusch, Tim Mansfeldt, Jürgen SpecoviusAbstract:Soils on sites of former coking and manufactured gas plants as well as on those of blast furnaces are frequently contaminated with Cyanides (CN). For assessing the possible risk arising from these hazardous compounds, it is necessary to analyze a considerable number of samples quickly as well as at low costs. Fourier transform infrared (FTIR) spectroscopy has the advantage of being much easier in handling compared to conventional wet-chemical methods for analyzing Cyanides. For testing FTIR spectroscopy in the application mentioned above, pure Cyanide compounds as well as contaminated purifier waste, blast furnace sludge, and spiked soils were investigated by the reflexion and the transmission techniques. Applicability of the attenuated total reflexion (ATR) technique was limited, since the absorption bands of the crystal used (diamond) overlapped in the range of the Cyanide-specific absorption. Although the environmental samples investigated have unfavorable optical properties, results obtained by the transmission technique (KBr pressed pellets) were much better than those obtained by the reflexion technique. Pure Cyanide compounds could be distinguished by their IR spectra because their absorption bands of the Cyanide-valence vibration differed in position, shape and intensity. The soil matrix did not interfere with either the intensity or the shape and position of the absorption maxima, as concluded from the IR spectra of spiked soil samples. Applying the transmission technique, Cyanides are detected at concentrations larger than 500 mg kg^−1 CN. However, the signal was low when the Cyanide concentration was below 1,000 mg kg^−1 CN. The FTIR spectroscopy is capable of detecting Cyanide compounds in soils and industrial wastes. Additionally, the method provides information about the Cyanide species, which is important in toxicological assessments. FIIR spectroscopy is a suitable method for a first survey and environmental assessment of Cyanide contaminated areas. Böden ehemaliger Kokereien, Stadtgasproduktionsstätten und Hochofenstandorte sind häufig mit Cyaniden (CN) belastet. Zur Prüfung einer möglichen Gefährdung, die von solchen Altlasten ausgeht, sind oft eine beträchtliche Anzahl von Proben schnell und kostengünstig zu untersuchen. Die Fourier-Transformations-Infrarot-(FTIR)-Spektrometrie hat den Vorteil, ohne den Aufwand konventioneller nasschemischer Analyseverfahren auszukommen. Um die FTIR-Spektrometrie für den genannten Einsatzbereich zu testen, wurden reine Cyanidverbindungen, Gasreinigungsmassen, Hochofengasschlämme und mit bekannten Cyanidmengen aufgestockte Böden sowohl mit der Reflexions- als auch mit der Transmissionstechnik untersucht. Die abgeschwächte Totalreflexion (ATR) war für die Untersuchung von Cyanidverbindungen nur bedingt geeignet, da sich Eigenabsorptionen des eingesetzten ATR-Kristalls (Diamant) mit den Spektralbereichen überschnitten, in denen Cyanidverbindungen charakteristische Absorptionen aufwiesen. Mit der Transmissionsmethode (KBr-Pressling) ließen sich trotz der ungünstigen optichen Eigenschaften der belasteten Substrate im Vergleich zur ATR-Technik bessere Ergebnisse erzielen. Cvanidverbindungen in reiner Form konnten unterschieden werden, da sowohl Lage als auch Form und Intensität ihrer Absorptionsspektren voneinander abwichen. Versuche, bei denen unbelastete Bodenproben mit Cyaniden versetzt wurden, haben gezeigt, dass sich die Bodenmatrix weder auf die Intensität noch auf die Lage und Form der Absorptionsmaxima auswirkt. Mit der Transmissions-methode konnten Cyanidkonzentration über 500 mg kg^−1 CN nachgewiesen werden, wobei unter 1000 mg kg^−1 CN jedoch nur sehr schwache Signale erhalten wurden. Mit der FTIR-Spektrometrie ist es möglich, Cyanidverbindungen in Böden und industriellen Abfällen nachzuweisen. Neben Aussagen über Cyanidbindungsverhältnisse, dies ist für eine toxikologische Bewertung wichtig, sind bei hohen Cyanidbelastungen quantitative Bestimmungen möglich. Die FTIR-Spektrometrie kann daher zur ersten Erfassung und Gefährdungsabschätzung von cyanidbelasteten Altlastverdachtsflächen eingesetzt werden.
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Cyanide in paper de‐inking sludge used as a soil amendment
Journal of Plant Nutrition and Soil Science, 2001Co-Authors: Tim MansfeldtAbstract:Paper de-inking sludge is processed during the recycling of paper, and is sometimes used as a soil amendment. In this study the effect of a compost application on the Cyanide (CN) status in soils of a public park was investigated. The compost was a mixture of chipped limbs and paper de-inking sludge. Furthermore, the Cyanide solubility was studied by conducting batch experiments with different pH levels. Total Cyanide in the amended soils ranged from 540 to 740 mg CN kg—1, and water soluble Cyanide from 170 to 370 μg CN l—1 as determined by means of an aqueous extract. Easily-liberatable Cyanides, which include the toxic free Cyanide (HCN and CN—) and weak metal-Cyanide complexes, were not present in the soil. From this result and the fact that iron blue pigments are used during paper printing, it can be inferred that Cyanides occurring here were exclusively stable iron-Cyanide complexes [Fe(CN)6]. With increasing pH the solubility of Cyanide increased. In contrast to soils of coking plants, in which Cyanide occur as Berlin blue, Fe4[Fe(CN)6]3, the Cyanide solubility in the paper de-inking sludge amended soils was substantially lower, especially in the neutral and alkaline range. Thus, Cyanides in paper de-inking sludge could be present as sparingly soluble metal-Cyanide compounds with the general formula A2B[FeII(CN)6] with A = K+, Na+ and B = Ca2+ or divalent transition metals and B2[FeII(CN)6] with B = divalent transition metals. Pollution exposure by the pathways soil human, and soil air human can be neglected. However, since leaching of iron-Cyanide complexes into the ground water cannot be excluded, and since they are decomposed to HCN when exposed to day light, environmental hazards by the pathway soil ground water surface water are possible. This is the risk arising from paper de-inking sludge applications to soils. Cyanid im als Bodenverbesserungsmittel eingesetzten Papier-Deinkingschlamm Papier-Deinkingschlamm ist ein Ruckstand der Altpapieraufbereitung und wird manchmal als Bodenverbesserungsmittel eingesetzt. In dieser Arbeit wurde der Einfluss einer Kompostapplikation auf den Cyanid-Status in Boden eines offentlichen Parks untersucht. Der Kompost war eine Mischung aus Rindenmulch und Papier-Deinkingschlamm. Weiterhin wurde die Cyanid-Loslichkeit in Schuttelversuchen bei unterschiedlichen pH-Werten getestet. Die Gesamtcyanidgehalte in den behandelten Boden reichten von 540 bis 740 mg CN kg—1, und die der gelosten Gesamtcyanid-Konzen-trationen im wassrigen Extrakt von 170 bis 370 μg CN l—1. Leicht freisetzbare Cyanide, welche die toxischen freien Cyanide (HCN und CN—) und schwachen Metallcyankomplexe umfassen, konnten nicht nachgewiesen werden. Aus diesem Ergebnis und der Tatsache, dass wahrend des Papierdrucks Eisenblau-Pigmente verwendet werden, kann gefolgert werden, dass die Cyanide ausschlieslich als stabile Eisencyankomplexe, [Fe(CN)6], vorlagen. Mit steigendem pH nahm die Loslichkeit der Cyanide zu. Im Gegensatz zu Kokereiboden, die mit Berliner Blau, Fe4[Fe(CN)6]3, belastetet sind, war die Cyanid-Loslichkeit in diesen Boden wesentlich geringer, besonders im neutralen bis alkalischem Bereich. Cyanide im Papier-Deinkingschlamm konnten in Form schwer loslicher Metallcyanverbindungen mit der allgemeinen Formel A2B[FeII(CN)6] mit A = K+, Na+ und B = Ca2+ oder ein zweiwertiges Ubergangsmetall und B2[FeII(CN)6] mit B = ein zweiwertiges Ubergangsmetall vorliegen. Gefahrdungen uber den Pfad Boden Mensch und Boden Luft Mensch konnen ausgeschlossen werden. Da aber ein Eintrag von Eisencyankomplexen in das Grundwasser moglich ist und diese im Tageslicht Blausaure freisetzen, ist eine Umweltgefahrdung uber den Pfad Boden Grundwasser Oberflachenwasser denkbar. Hierin liegt ein Risiko in der Anwendung von Papier-Deinkingschlamm als Bodenverbesserungsmittel.
Xiaoqiang Chen - One of the best experts on this subject based on the ideXlab platform.
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a near infrared fluorescent sensor for detection of Cyanide in aqueous solution and its application for bioimaging
Chemical Communications, 2010Co-Authors: Xiaoqiang Chen, Nari Song, Yongsuk Jeong, Injae Shin, Sungsu Park, Juyoung YoonAbstract:A new NIR fluorescent sensor based on an amine-substituted heptamethine cyanine dye displayed a highly selective fluorescence enhancement with Cyanide in aqueous solutions, and was applied for the imaging of anthropogenic and biogenic Cyanide.
