Effect of cyanide ions (CN-) extracted from cassava (Manihotesculenta Crantz) on Alveolar Epithelial Cells (A549 cells).

Cassava (Manihotesculenta Crantz) is one of the most important root crops in tropical countries. It is a major source of cyanogenic glycosides viz. linamarin and lotaustralin, and these on breakdown liberate HCN and ketone. Cassava cyanide extract (CCE) from cassava leaves and tuber rinds were formulated as a biopesticide against certain borer insect pests of horticultural crops. Adenocarcinomic human alveolar basal epithelial cells (A549) were treated with three different concentrations (100, 200, 400 ppm) of CCE. The MTT and NRU assays showed dose-dependent cytotoxicity. The DCFH-DA assay does not show any free radical scavenging activity, whereas the NRR assay showed a reduction in the nitrile radicals with an increase in the concentration of the bioactive compound. A negative correlation was found between the concentration of the bioactive principles and mitochondrial and lysosomal functions. Various cellular assays demonstrated the cellular response of the CCE, and it was found that at higher concentration (400 ppm), the CCE exert a significant necrotic cell death rather than apoptosis. The results of the study indicated that the CCE have a remarkable tendency of anti-proliferative ability.

Anodic oxidation of coke oven wastewater: Multiparameter optimization for simultaneous removal of cyanide, COD and phenol.

Anodic oxidation of industrial wastewater from a coke oven plant having cyanide including thiocyanate (280 mg L(-1)), chemical oxygen demand (COD - 1520 mg L(-1)) and phenol (900 mg L(-1)) was carried out using a novel PbO2 anode. From univariate optimization study, low NaCl concentration, acidic pH, high current density and temperature were found beneficial for the oxidation. Multivariate optimization was performed with cyanide including thiocyanate, COD and phenol removal efficiencies as a function of changes in initial pH, NaCl concentration and current density using Box-Behnken experimental design. Optimization was performed for maximizing the removal efficiencies of these three parameters simultaneously. The optimum condition was obtained as initial pH 3.95, NaCl as 1 g L(-1) and current density of 6.7 mA cm(-2), for which the predicted removal efficiencies were 99.6%, 86.7% and 99.7% for cyanide including thiocyanate, COD and phenol respectively. It was in agreement with the values obtained experimentally as 99.1%, 85.2% and 99.7% respectively for these parameters. The optimum conditions with initial pH constrained to a range of 6-8 was initial pH 6, NaCl as 1.31 g L(-1) and current density as 6.7 mA cm(-2). The predicted removal efficiencies were 99%, 86.7% and 99.6% for the three parameters. The efficiencies obtained experimentally were in agreement at 99%, 87.8% and 99.6% respectively. The cost of operation for degradation at optimum conditions was calculated as 21.4 USD m(-3).

Membrane-integrated physico-chemical treatment of coke-oven wastewater: transport modelling and economic evaluation.

A modelling and simulation study with economic evaluation was carried out for an advanced membrane-integrated hybrid treatment process that ensures reuse of water with recovery of ammoniacal nitrogen as struvite from coke-oven wastewater. Linearized transport model was developed based on extended Nernst-Plank and concentration polarization modulus equation. Effects of pH, transmembrane pressure and cross-flow rate of interest on membrane charge density, solute rejection and solvent flux were investigated. The membrane module was successful in yielding a pure water flux as high as 120 L m(-2) h(-1) removing more than 95 and 96% of the cyanide and phenol, respectively, while permeating more than 90% NH4 (+)-N at a transmembrane pressure of only 15 × 10(2) KPa and at a pH of 10 for a volumetric cross-flow rate of 800 L h(-1). The Fenton's reagents were used to degrade more than 99% of pollutants present in the concentrated stream. The developed model could successfully predict the plant performance as reflected in the very low relative error (0.01-0.12) and overall high correlation coefficient (R(2) > 0.96). Economic analysis indicated that such a membrane-integrated hybrid system could be quite promising in coke wastewater treatment at low cost i.e. $0.934/m(2) of wastewater.

Membrane-integrated hybrid system for the effective treatment of ammoniacal wastewater of coke-making plant: a volume reduction approach.

Nanofiltration (NF) of ammoniacal wastewater containing phenol and cyanide has been investigated for effective separation of these hazardous pollutants and for the subsequent downstream chemical treatment resulting in valuable by-product generation. Four different types of composite polyamide commercial NF membranes (Sepro, USA) were tested under different operating conditions including transmembrane pressure and recovery rate (RR). At a transmembrane pressure of 15 bar, the achieved rejection of cyanide and phenol were 95% and 93%, respectively (concentrated stream) when the permeate contained 85% of ammonium-N. A high flux of 120 L m-2 h-1 was achieved during NF at a concentrated mode, with a volumetric cross-flow rate of 800 L h-1 at a pH of 10.0. The RR was 60% for the NF 1 membrane. Fenton's reagents (7.0 and 3.75 g L-1 H202 and FeSO4 . 7H20, respectively) were used to degrade more than 99% of pollutants present in the concentrated stream. In the permeate side, 97% of NH4+ -N was precipitated out as struvite by using Mg2+ : NH4 : PO+4 in 1:1:1 molar ratio at pH 9.0.

Enantiomeric differentiation by synthetic helical polymers.

Recent advances in the synthesis of helical polymers and their applications as chiral materials, in particular chiral stationary phases (CSPs), for high-performance liquid chromatography (HPLC) are reviewed with an emphasis on the key role of the helical conformations with one-handedness for the prominent chiral recognition of enantiomers. The historical background of artificial optically active helical polymers is also briefly described.

Recovery of iron from cyanide tailings with reduction roasting-water leaching followed by magnetic separation.

Cyanide tailing is a kind of solid waste produced in the process of gold extraction from gold ore. In this paper, recovery of iron from cyanide tailings was studied with reduction roasting-water leaching process followed by magnetic separation. After analysis of chemical composition and crystalline phase, the effects of different parameters on recovery of iron were chiefly introduced. Systematic studies indicate that the high recovery rate and grade of magnetic concentrate of iron can be achieved under the following conditions: weight ratios of cyanide tailings/activated carbon/sodium carbonate/sodium sulfate, 100:10:3:10; temperature, 50 °C; time, 60 min at the reduction roasting stage; the liquid to solid ratio is 15:1 (ml/g), leaching at 60 °C for 5 min and stirring speed at 20 r/min at water-leaching; exciting current is 2A at magnetic separation. The iron grade of magnetic concentrate was 59.11% and the recovery ratio was 75.12%. The mineralography of cyanide tailings, roasted product, water-leached sample, magnetic concentrate and magnetic tailings were studied by X-ray powder diffraction (XRD) technique. The microstructures of above products except magnetic tailings were also analyzed by scanning electron microscope (SEM) and energy disperse spectroscopy (EDS) to help understand the mechanism.

The reaction of HOCl and cyanocobalamin: corrin destruction and the liberation of cyanogen chloride.

Overproduction of hypochlorous acid (HOCl) has been associated with the development of a variety of disorders such as inflammation, heart disease, pulmonary fibrosis, and cancer through its ability to modify various biomolecules. HOCl is a potent oxidant generated by the myeloperoxidase-hydrogen peroxide-chloride system. Recently, we have provided evidence to support the important link between higher levels of HOCl and heme destruction and free iron release from hemoglobin and RBCs. Our current findings extend this work and show the ability of HOCl to mediate the destruction of metal-ion derivatives of tetrapyrrole macrocyclic rings, such as cyanocobalamin (Cobl), a common pharmacological form of vitamin B12. Cyanocobalamin is a water-soluble vitamin that plays an essential role as an enzyme cofactor and antioxidant, modulating nucleic acid metabolism and gene regulation. It is widely used as a therapeutic agent and supplement, because of its efficacy and stability. In this report, we demonstrate that although Cobl can be an excellent antioxidant, exposure to high levels of HOCl can overcome the beneficial effects of Cobl and generate proinflammatory reaction products. Our rapid kinetic, HPLC, and mass spectrometric analyses showed that HOCl can mediate corrin ring destruction and liberate cyanogen chloride (CNCl) through a mechanism that initially involves α-axial ligand replacement in Cobl to form a chlorinated derivative, hydrolysis, and cleavage of the phosphonucleotide moiety. Additionally, it can liberate free Co, which can perpetuate metal-ion-induced oxidant stress. Taken together, these results are the first report of the generation of toxic molecular products through the interaction of Cobl with HOCl.

Cyanide uptake from wastewater by modified natrolite zeolite-iron oxyhydroxide system: application of isotherm and kinetic models.

A method for the removal of cyanides from wastewater is described. The method involves the adsorption of cyanides by a modified natural zeolite (natrolite) using batch technique. A new iron oxyhydroxide-natrolite system was used in this study. A combination of XRD, XRF and FTIR spectroscopies, as well as TG/DSC thermal analyses was used for characterization of zeolitic materials. Effects of parameters such as pH, amount of adsorbent and contact time on the cyanide removing yield are studied. It was observed that the yield increases by increasing dosage of adsorbent and contact time at a fixed pH 7.5. A yield of 82% was achieved at optimum conditions for removing cyanide from industrial wastewaters. The experimental data obtained for optimum conditions were selected for modeling the adsorption behavior of the materials using six isotherm equations (Freundlich, Langmuir, Langmuir-Freundlich, Dubinin-Radushkevich, Redlich-Peterson and Toth). The obtained modeling results indicated that, although the three-parameter models, taking into account the surface heterogeneity, provided the closest approach to the measurement data, the parameters estimates could be highly biased. The kinetic studies proved that the second-order kinetic was the applicable model.

Cyanide produced by human isolates of Pseudomonas aeruginosa contributes to lethality in Drosophila melanogaster.

Some Pseudomonas aeruginosa strains are cyanogenic, and cyanide may contribute to the bacterium's virulence. Using human isolates of P. aeruginosa, we have shown that Drosophila melanogaster suspended above cyanogenic strains become motionless and develop bradycardia and that flies injected with cyanogenic bacterial strains die more rapidly than those injected with noncyanogenic strains. Flies exposed to cyanogenic strains had high cyanide and low adenosine triphosphate (ATP) concentrations in body extracts, and treatment with a cyanide antidote equalized survival of flies injected with cyanogenic and noncyanogenic strains. P. aeruginosa PAO1 strain with a mutation in the hydrogen cyanide synthase gene cluster was much less toxic to flies than the parental cyanogenic strain or 2 knock-in strains. Transgenic flies overexpressing rhodanese, which detoxifies cyanide by converting it to thiocyanate, were resistant to cyanide and the increased virulence of cyanogenic strains. We conclude that D. melanogaster is a good model for studying cyanide produced by P. aeruginosa.

Separation and determination of metallocyanide complexes of Fe(II), Ni(II) and Co(III) by ion-interaction chromatography with membrane suppressed conductivity detection applied to analysis of oil refinery streams (sour water).

A separation and determination method for the analysis of cyanometallic complexes of Fe(II), Ni(II) and Co(III) was developed to be applied to the analysis of petroleum refinery streams (sour water). Ion-interaction chromatography was used employing an analytical column IonPac NS1 10 microm and a chromatographic system ICS 2500 equipped with a membrane conductivity suppression ASRS ultra 4mm, both supplied by Dionex Corporation. The mobile phase was composed of 2 mmol l(-1) TBAOH, 1 mmol l(-1) Na(2)CO(3), 0.1 mol l(-1) NaCN and ACN (77:23, v/v), flowing at 0.7 ml min(-1). At the optimized conditions, detection limits estimated by the calibration curve parameters and relative standard deviation were: 0.002 mg CNl(-1) and 3.1% for Fe(CN)(6)(4-); 0.003 mg CNl(-1) and 2.5% for Ni(CN)(4)(2-) and 0.003 mg CNl(-1) and 2.8% for Co(CN)(6)(3-). Sour water samples without any pretreatment (except membrane filtration) from a petroleum refinery in Brazil were analyzed successfully by external calibration method.

Treatment of praziquantel wastewater using the integrated process of coagulation and gas membrane absorption.

Praziquantel is an anti-schistosoma drug, its wastewater contains numerous cyanide and other colloid pollutant. A novel integrated treatment process was proposed in this study, i.e., using coagulation to eliminate colloid pollutant and using gas membrane absorption (GMA) to remove cyanide. The optimization of coagulation condition, determination of cyanide removal rate, elimination of membrane fouling, and overall evaluation of the integrated process for the treatment of praziquantel wastewater were investigated in this study. Good results were achieved: turbidity reduced from 700 NTU to 10-40 NTU, 92% COD was removed, cyanide concentration dropped from 3500 mg/L to below 0.5 mg/L, recovery rate of cyanide reached to 98%, and operation cost could be entirely compensated from the gain of recovered cyanide. The results demonstrate that the novel integrated process offers a number of advantages over alkaline chlorination method in the treatment of praziquantel wastewater: cyanide can be reused rather than destroyed, no secondary pollutants are produced, the operation cost is low and the equipment etching is avoided.

Iron(VI) and iron(V) oxidation of copper(I) cyanide.

Copper(Il) cyanide (Cu(CN)4(3-)) in the gold mine industry presentsthe biggest concern in cyanide management because it is much more stable than free cyanide. Cu(CN)4(3-) is highlytoxic to aquatic life; therefore, environmentally friendly techniques are required for the removal of Cu(CN)4(3-) from gold mine effluent. The oxidation of Cu(CN)4(3-) by iron-(VI) (FeVIO4(2-), Fe(VI)) and iron(V) (FeVO4(3-), Fe(V)) was studied using stopped-flow and premix pulse radiolysis techniques. The stoichiometry with Fe(VI) was determined to be 5HFeO(4-) + Cu(CN)4(3-) + 8H2O - > 5Fe(OH)3 + Cu2+ + 4CNO- +3/202 + 6OH-. The rate law for the oxidation of Cu(CN)4(3-) by Fe(VI) was found to be first-order with each reactant. The rates decreased with increasing pH and were mostly related to a decrease in concentration of reactive protonated Fe(VI) species, HFeO4-. A mechanism is proposed that agrees with the observed reaction stoichiometry and rate law. The rate constant for the oxidation of Cu(CN)4(3-) by Fe(V) was determined at pH 12.0 as 1.35 +/- 0.02 x 10(7) M(-1) s(-1), which is approximately 3 orders of magnitude larger than Fe(VI). Results indicate that Fe(VI) is highly efficient for removal of cyanides in gold mill effluent.

Characterization of the catalytic films formed on stainless steel anodes employed for the electrochemical treatment of cuprocyanide wastewaters.

Surface composition changes at stainless steel anodes in an electrochemical reactor applied for the electrochemical treatment of cuprocyanide-containing wastewaters operating under different hydrodynamic conditions were investigated. Under highly alkaline conditions in situ generation of a surface film on the anode with catalytic properties towards cyanide electrolysis was observed. X-ray photoelectron spectroscopy (XPS) results demonstrated that only copper oxi-hydroxide compounds constitute the surface film developed on the stainless steel anodes, as no traces of N- and C-containing compounds were observed. The collected XPS spectra revealed relevant details concerning the oxidation states of copper in the film, and the products Cu2O, CuO and Cu(OH)2 were identified on the surface of the anodes. However, the quantitative proportions of the individual products differ and depend on the type of mixing employed during reactor operation.

Cyanide removal from wastewater using gas membranes: pilot-scale study.

Results are presented for the removal of cyanide from four different wastewaters using hollow-fiber gas membranes. The pilot-scale membrane facility had a maximum treatment capacity of 1000 L using 10 hollow-fiber modules with a total membrane surface area of 180 m2. The results are in general agreement with previous laboratory-scale studies. However, different wastewaters contain different dissolved solutes. These dissolved solutes reduce the predicted efficiency of the cyanide removal process and the purity of the recovered cyanide. Other volatile species present in the wastewater could be removed with the cyanide into the strip solution. Further osmotic pressure differences between the wastewater and strip solution could lead to water vapor passing through the gas-filled pores of the microporous hollow-fiber membranes.

Melanocins A, B and C, new melanin synthesis inhibitors produced by Eupenicillium shearii. I. Taxonomy, fermentation, isolation and biological properties.

New melanin synthesis inhibitors, melanocins A, B and C, were isolated from the fermentation broth and mycelium extract of Eupenicillium shearii F80695. Melanocin A, an isocyanide compound, inhibited mushroom tyrosinase and melanin biosynthesis of B16 melanoma cells with IC50 value of 9.0 nM and MIC value of 0.9 microM, respectively. Melanocin A also inhibited growth of Streptomyces bikiniensis. While, the structurally very related but non-isocyanide compounds melanocins B and C did not show inhibitory activity in these assays. Melanocins A, B and C showed potent antioxidant activity with scavenging activity of DPPH radical and superoxide anion radical.