Removal of Copper

The removal of copper from the pregnant nickel solution in the Sherritt-Gordon process is an example of purification by precipitation of a fairly insoluble compound. First, in the copper boil step, ammonia is driven off by heating the solution, and some copper sulfide precipitates. The residual copper is removed by a dding hydrogen sulfide for the chemical precipitation of mote copper sulfide. 

Reaction of Bisglycinatocopper(II). Bisglycinatocopper(II) [13479-54-4] condenses with ahphatic aldehydes. Removal of copper from the condensate results in P-hydroxy-a-amino acid. This is a classical synthetic method of DL-threonine, but the formation of i //o-isomer is unavoidable. 

A classic example of cementation is the removal of copper from solution by elemental iron. 

Note that the brackets, [ ], refer to the concentration of the species. K,p is the solubility product constant hence [Cu " ] and [OH] are equal to the molar concentrations of copper and hydroxyl ions, respectively. The K p is commonly used in determining suitable precipitation reactions for removal of ionic species from solution. In the same example, the pH for removal of copper to any specified concentration can be determined by substituting the molar concentration into the following equation ... 

Hydrochloric acid/thiourea [thiocarbamide, CS(NH2)2], The procedure for cleaning iron oxides containing copper and copper oxides is the same as for cleaning iron oxides alone. A typical formulation is 5% HC1 with 2% thiourea, plus corrosion inhibitor, wetting agent, and antifoam. A complete removal of copper is required because the passivation process otherwise will not be effective. 

The first STM evidence for the facile transport of metal atoms during chemisorption was for oxygen chemisorption at a Cu(110) surface at room temperature 10 the conventional Langmuir model is that the surface substrate atoms are immobile. The reconstruction involved the removal of copper atoms from steps [eqn (1)], resulting in an added row structure and the development of a (2 x 1)0 overlayer [eqn (2)]. The steps present at the Cu(llO) surface are... 

The sulfur liberated is involved in a complicated sequence of reactions which lead to almost complete removal of copper from the matte as very insoluble CuS(S).101-103... 

The use of GSNO in vasodilator research is particularly unsafe as the effect of copper ions, as determined by in vitro studies, is much more complex than with SNAP. Briefly, Cu(I) ions complex not only with GSNO but also with glutathione disulfide (a reaction product) and this means that the concentration of Cu(l) ions falls as the reaction proceeds, killing the reaction when all the Cu(I) ions have been complexed [22]. The absence of any observed effect when GSNO is used as a vasodilator may be due to removal of copper ions by complexation with glutathione disulfide. 

Takada and Ishimatari [20] extracted alkylbenzenes with normal C10-C14 and branched Cn-C13 alkyl chains from marine and coastal sediment and suspended matter in benzene methanol. The extract in benzene was then applied to a Florisil column for removal of copper sulphide and polar materials, and then subjected to silica gel column chromatography. Alkyl benzenes were quantified and identified using gas chromatography with flame ionization detection. The recoveries of alkyl benzenes were 81-94%. 

Nami Kartal, S. (2003). Removal of copper, chromium, and arsenic from CCA-C treated wood by EDTA extraction. Waste Management, 23(6), 537-546. 

Cementation is the process of recovery of metals from dilute aqueous solution by reductive precipitation using another metal with a more negative electrode potential, e.g., Cu + Fe° Cu° + Fe. The product, in this case cement copper, is relatively impure because of iron contamination. However, cementation can be used in conjunction with a solvent extraction flow sheet to remove small amounts of a metallic impurity, for example, removal of copper from a nickel solution by cementation with nickel powder. Here the dissolved nickel conveniently augments the nickel already in solution. 

When the sulfide ore carroUite, CuS C02S3, is the starting material, first sulfides are separated by flotation with frothers. Various flotation processes are applied. The products are then treated with dilute sulfuric acid producing a solution known as copper-cobalt concentrate. This solution is then electrolyzed to remove copper. After the removal of copper, the solution is treated with calcium hydroxide to precipitate cobalt as hydroxide. Cobalt hydroxide is filtered out and separated from other impurities. Pure cobalt hydroxide then is dissolved in sulfuric acid and the solution is again electrolyzed. Electrolysis deposits metallic cobalt on the cathode. 

An anion exchange resin (e.g. Amberlite R-120) was treated with protonated dithiooxamine, H2NC(S)C(S)NH2 Using the supported ligand, quantitative removal of copper, cadmium, and lead ion solutions at neutral or slightly alkaline solutions of deionized or tap water, but poor results were obtained with sea water [22]. 

The results of the study are summarized in part in Table 2 and demonstrate two useful consequences. The first result was an effective removal of nuisance transition metal ions 98% removal of zinc ion, 93% removal of nickel(II), 73% removal of copper(II) species. The second result, as a consequence, was the ability to reduce the fresh water intake by recycling reducing water usage by 67%. 

Pearson, F., "Removal of Copper from Acidic Water in a Flume Packed with Crushed Limestone, Proceedings of Hazardous Materials Management Conference and Exposition, Disneyland Hotel, April 5-7, 1988, Sponsored by Association of Bay Area Governments, Oakland, Calif, pp. 431-441, 1988. 

Ribeiro, A.B. and Mexia, J.T. (1997) A dynamic model for the electrokinetic removal of copper from a polluted soil.f. Hazardous Mat., 56, 257-271. 

Work has also been conducted on the removal of copper from milk. Thiosuccinylated aminoethyl cellulose has been used to remove more than 90% of the copper from milk (Roh et al., 1976). Glass-bound trypsin has been used to inhibit metal-induced lipid oxidation (Shipe et al., 1972). Further work by Gregory and Shipe (1975) showed that ageing milk before exposure to a metal catalyst reduced the extent of lipid oxidation and... 

Robertson, G.L. 1993. Food Packaging—Principles and Practice. Marcel Dekker, New York. Roh, J.K., Bradley, R.L., Richardson, T., Weckel, K.G. 1976. Removal of copper from milk.. / Dairy Sci. 59, 382-385. 

We believe that Cu(II) binding to the DNA bases alters the DNA conformation in such a way that a gross alteration occurs in the packing of the DNA molecules. The addition and subsequent removal of copper make this a reversible process. 

Surface topography of Kapton polyimide as-received, seeded with copper, after the 450°C heat treatment, and after removal of copper oxide by acid etching was examined by scanning electron microscopy. Cross-sectional analysis of Kapton seeded with copper and after 450°C heat treatment was carried out by transmission electron microscopy. 

Isabel, V., Nuria, R, Maria, M., Nuria, M., Jordi, R, and Joan, S. 2004. Removal of copper and nickel ions from aqueous solutions by grape stalks wastes. Water Research, 38 992-1002. 

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