Basic Copper Carbonate Research Articles

Electrosynthesis and thermal characterization of basic copper carbonate nanoparticles

AbstractThe present study concerns the electrochemical synthesis of basic copper carbonate nanoparticles by oxidation of metallic copper on the anode in an aqueous bicarbonate solution. This simple and one-step preparation can be considered as green synthesis. The scanning electron microscopy (SEM) analysis indicates that average particle size of the product is in the range of about 70 nm. On the other hand, basic copper carbonate micro-powder has been prepared, by mixing solutions of copper(II) sulphate and sodiu bicarbonate. The SEM analysis showed that the size of particles prepared in the same way is in the range of about 1 µm. In another part of this study, the thermal decomposition of micro and nanoparticles of copper carbonate produced by various methods was studied in air using TG-DTA techniques. The results of thermal study show that the decomposition of both samples occurs in single step. Also, the TG-DTA analysis of the nanoparticles indicates that the main thermal degradation occurs in the temperature range of 245–315°C. However, microparticles of Cu(OH)2 · CuCO3 decomposed endothermally in the temperature range of 230–330°C.

Thermal characterization of individual and mixed basic copper carbonate and ammonium metavanadate systems

The thermal behaviour of individual and mixed solids, with different molar ratios, of basic copper carbonate and ammonium metavanadate was reported. The pure and mixed solids were thermally treated at 300, 500, 750 and 1000 °C. The thermal products at various calcination temperatures were characterized by means of thermal analyses (TG–DTG–DTA), X-ray diffraction (XRD) and electron spin resonance (ESR) techniques. The catalytic activity of all solids was measured using hydrogen peroxide decomposition at 30, 40 and 50 °C. The results revealed that pure basic copper carbonate decomposed to CuO at 300 °C and to Cu 2O at temperature above 950 °C, where as pure ammonium vanadate decomposed to (NH 4) 2V 6O 16 and NH 4V 4O 10 as an intermediate compound at 250 and 350 °C before the formation of V 2O 5 at 450 °C. CuO enhanced the formation of V 2O 5 at 300 °C. A series of copper vanadate phases were detected, Cu 5V 2O 10, Cu 2V 2O 7 and Cu 3V 5O 4, for the mixtures 3Cu:1V, 1Cu:1V and 1Cu:3V preheated at 750 °C, respectively. These phases were formed as a result of solid–solid interactions between copper and vanadium oxides. The calcination temperature and the composition of the Cu–V mixtures affect the degree of crystallinity and pattern intensities of different phases detected at treatment temperatures ranged between 300 and 1000 °C. The catalytic activity of mixed CuO–V 2O 5 was found to be greater than that of single oxides obtained at the same calcination temperatures. This might be attributed to increase in the concentration of active sites by creation of new ion pairs. No measurable catalytic activity was observed for all solids calcined at 750 and 1000 °C. This might be attributed to restriction of catalytically active constituents.

Deterioration of limestone structures associated with copper staining

Sixty limestone monuments in Central London, UK, with copper staining from brass or bronze attachments, were surveyed. Severe spalling was noted at some copper-stained sites. The survey suggests that copper initially protects the surface, but causes stone deterioration after around 70 years. Samples from four limestone monuments were analysed microbiologically and using ESEM/EDX. EDX analyses suggested the build-up of salts below a basic copper carbonate skin (salting) as the most probable explanation of the observed deterioration. Copper-stained stone was free of photosynthetic microorganisms and yielded relatively few other microorganisms. ESEM and EDX analyses of a well-conserved limestone monument surface free of copper showed the almost complete conversion of surface limestone to gypsum. The grey/brown biofilms consisted of actinomycetes and filamentous fungi. The results indicate that copper initially prevents and then enhances limestone deterioration, and that atmospheric pollutants are far less harmful than phototrophic biofilms, since surface areas completely converted to gypsum are well preserved after more than 100 years.

Production and characterization of pure and doped copper ferrite nanoparticles

The effects of calcination temperature and doping with either MgO or Al 2O 3 (2 and 6 mol %) on solid-state reactions between CuO and Fe 2O 3 have been investigated using DSC, XRD, IR, SEM and TEM techniques. The mechanical mixing of known amounts of basic copper carbonate and α-Fe 2O 3 were employed, however magnesium and aluminum were added as magnesium and aluminum nitrates. Pure and doped mixed solids were subjected to heat treatment at 800–1000 °C. The results obtained revealed that CuO underwent solid–solid interaction with Fe 2O 3 at temperatures starting from 800 °C producing nanocrystalline CuFe 2O 4. The degree of propagation of this reaction increases progressively by increasing both the calcination temperature and the amounts of dopant added. The promotion effect of MgO and Al 2O 3 towards the ferrite formation was attributed to an effective increase in the mobility of the various reacting cations. The activation energy of CuFe 2O 4 formation was evaluated to be 150, 100, and 115 kJ mol −1 for pure mixed solids and those doped with 6 mol % MgO and 6 mol % Al 2O 3, respectively.

Raman spectroscopic analysis of azurite blackening

AbstractAzurite is a basic copper carbonate pigment largely employed in painting realization. The areas painted with azurite are easily alterable and are often less resistant than the other parts of artworks. The azurite alteration in a black pigment, the copper oxide (tenorite), has been studied by micro‐Raman spectroscopy. The blackening can be due to thermal or chemical alterations: in the second case the alterations being due to the presence of alkaline conditions. Laser‐induced degradation of azurite has been studied as a function of the grain size. The results show that the temperature of the grains decreases as the size increases, and azurite degrades into tenorite only below the critical value of 25 µm. To study the chemical alteration of azurite, the pigment has been applied on the plaster of terracotta samples and analyzed at different pH values by micro‐Raman spectroscopy. As opposed to most part of the analytical techniques, it can detect the presence of both azurite and tenorite molecules in the same micro areas, and provides a valuable tool to determine azurite degradation. Copyright © 2008 John Wiley & Sons, Ltd.

Zu den Kristallstrukturen der Übergangsmetall(II)‐Dodekahydro‐closo‐Dodekaborat‐Hydrate Cu(H2O)5,5[B12H12]·2,5 H2O und Zn(H2O)6[B12H12]·6 H2O

AbstractOn the Crystal Structures of the Transition‐Metal(II) Dodecahydro‐closo‐Dodecaborate Hydrates Cu(H2O)5.5[B12H12]·2.5 H2O and Zn(H2O)6[B12H12]·6 H2OBy neutralization of an aqueous solution of the free acid (H3O)2[B12H12] with basic copper(II) carbonate or zinc carbonate, blue lath‐shaped single crystals of the octahydrate Cu[B12H12]·8 H2O (≡ Cu(H2O)5.5[B12H12]·2.5 H2O) and colourless face‐rich single crystals of the dodecahydrate Zn[B12H12]·12 H2O (≡ Zn(H2O)6[B12H12]·6 H2O) could be isolated after isothermic evaporation. Copper(II) dodecahydro‐closo‐dodecaborate octahydrate crystallizes at room temperature in the monoclinic system with the non‐centrosymmetric space group Pm (Cu(H2O)5.5[B12H12]·2.5 H2O: a = 768.23(5), b = 1434.48(9), c = 777.31(5) pm, β = 90.894(6)°; Z = 2), whereas zinc dodecahydro‐closo‐dodecaborate dodecahydrate crystallizes cubic in the likewise non‐centrosymmetric space group F23 (Zn(H2O)6[B12H12]·6 H2O: a = 1637.43(9) pm; Z = 8). The crystal structure of Cu(H2O)5.5[B12H12]·2.5 H2O can be described as a monoclinic distortion variant of the CsCl‐type arrangement. As characteristic feature the formation of isolated [Cu2(H2O)11]4+ units as a condensate of two corner‐linked Jahn‐Teller distorted [Cu(H2O)6]2+ octahedra via an oxygen atom of crystal water can be considered. Since “zeolitic” water of hydratation is also present, obviously both classical H–Oδ−···+δH–O and non‐classical B–Hδ−···+δH–O hydrogen bonds play a significant role for the stabilization of the structure. A direct coordinative influence of the quasi‐icosahedral [B12H12]2− anions on the Cu2+ cations has not been determined. The zinc compound Zn(H2O)6[B12H12]·6 H2O crystallizes in a NaTl‐type related structure. Two crystallographically different [Zn(H2O)6]2+ octahedra are present, which only differ in their relative orientation within the packing of the [B12H12]2− anions. The stabilization of the crystal structure takes place mainly via H–Oδ−···+δH–O hydrogen bonds, since again the hydrogen atoms of the [B12H12]2− anions have no direct coordinative influence on the Zn2+ cations.

Re-dispersion of metal carbonate powders in dispersive media of various chemical nature

Abstract The influence of dispersive medium on the aggregation–disaggregation processes during the preparation of the suspensions of basic nickel and copper carbonates and manganese and cobalt carbonates was investigated. Distilled water, isopropyl and isobutyl alcohol, 1,4-dioxane served as dispersive media. Obtained results are discussed within the framework of the model of the powder re-dispersion in liquid media. The factors that affect the powder re-dispersion and the aggregative stability of the investigated suspensions are analyzed. It was shown that two consecutive processes affect the re-dispersion degree of the powders: spreading of the liquid on the particle surface by permeating into open polydisperse pores, and permeation of the liquid into closed pores. The contribution of each of the process depends on the powder dispersity and on the surface tension at the liquid–air interface.

Mechanochemical reforming of powder and acidic properties of copper cyclo-tetraphosphates

Copper cyclo-tetraphosphate was synthesized from basic copper carbonate and phosphoric acid and then treated with the planetary mill for several minutes. The un-milled and milled samples were characterized by simultaneous thermogravimetry-differential thermal analyses, X-ray diffraction, and Fourier transform infrared spectroscopy. SEM images, particle size distribution, specific surface area, acidic properties of the materials were also used for the estimation. Furthermore, as their application, the adsorption ratio of trimethylamine was measured. The mechanochemical reforming of copper phosphates was clarified from the changes of some properties that were related with the refinement and cleavage of chemical bonding.

Synthesis and antiinflammatory activity of n-aryl anthranilic acid and its derivatives

N-aryl anthranilic acid and its derivatives (3a-f) have been synthesized via Ullmann condensation of o-chloro benzoic acid with various substituted anilines (2a-f) in the presence of cupric oxide and anhydrous potassium carbonate. All the synthesized compounds (3a-f) were characterized by mp, TLC, UV, IR, 1 H NMR and mass spectral analysis. All the synthesized compounds (3a-f) were screened for their antiinflammatory activity by carrageenan induced rat paw edema method. All the synthesized compounds (3a-f) showed significant antiinflammatory activity. Compounds 3a and 3c were found to be the most potent compounds.

Effect of Pb, Cu and Fe compounds on the germination and early seedling growth of tomato varieties

The germination and early seedling growth of two tomato seed varieties (NHLe 158-3 and ROMA VF) were investigated using five levels (0% 0.001% 0.01% 0.1% 1%) of lead acetate, cupric carbonate and ferric chloride respectively. The experiment was conducted under 12±2h photoperiodic laboratory condition in a laboratory germinator. The results showed that the aggregate germination percentage (AGP) as well as the coefficient of germination velocity (CGV) decreased with increase in the levels of metallic compounds on the two tomato varieties. The decreases in AGP and CGV were significant ( p

Co-removal of hexavalent chromium through copper precipitation in synthetic wastewater.

The mechanisms of hexavalent chromium [Cr(VI)] co-removal with copper [Cu(II)] during homogeneous precipitation were studied with batch tests using a synthetic solution containing Cr(VI) and Cu(II). Metal precipitation was induced by adding Na2CO3 stepwise to different pH, and the respective removals of Cu(II) and Cr(VI) were measured. At the same time, the relative quantities of Cu(II) and Cr(VI) in the precipitates were also analyzed to establish their stoichiometric relationship. The results indicated that, in a solution containing 150 mg/L Cu(II) and 60 mg/L Cr(VI), the initial co-removal of Cr(VII with Cu(II) began at pH 5.0 and completed at pH 6.2. At pH 5.0-5.2, coprecipitation took place through the formation of copper-chromium-bearing solids [such as CuCrO4 and/or CuCrO4 x 2Cu(OH)2]. Thereafter, the remaining soluble copper started to react with carbonate in a heterogeneous environment to form the negatively charged basic copper carbonate precipitates [CuCO3 x Cu(OH)2], which subsequently adsorbed additional Cr(VI) (or HCrO4-) at pH 5.2-6.2. The maximum Cr(VI) co-removal took place at pH 6.2. Between the two mechanisms, co-precipitation accounted for about 29% of the total chromium's co-removal while the remaining 71% was attributed to surface adsorption, mainly through electrostatic attraction and ligand exchange. When the solution pH was increased to beyond 7.5, a surface charge reversal took place on the basic copper carbonate solids, and this led to some Cr(VI) desorption. Thus, the extent of Cr(VI) adsorption is highly pH dependent.

Chemical Reactions Between Copper Pigments and Oleoresinous Media

study demonstrates that resin and fatty acids are able to extract copper(II) ions from verdigris (copper acetate) and verditer (basic copper carbonate). Ligand exchange reactions of basic copper carbonate with fatty acids and resin acids are much slower than is the case with copper acetate. The browning of paint layers is closely correlated with the relative ease of copper extraction; the copper diffuses in the form of fatty acid or resin carboxylic acid complexes. These complexes are formed in the painting layer during grinding of the pigment with binding media containing oleoresin acids, as well as being formed at the interface of this layer and organic upper layers, such as varnishes.

Formation of copper oxide through NaNO 3–KNO 3 eutectic melt and its catalytic activity in the decomposition of ammonium perchlorate

The decomposition of basic copper carbonate in the presence and absence of NaNO 3–KNO 3 eutectic melt has been studied by employing isothermal TG and dynamic TG/DSC techniques. The rate constants for the decomposition in the presence of eutectic melt were found to be higher than when carbonate was heated alone. In both the cases copper oxide was found to be the end product. Catalytic activity of copper oxide obtained by the two methods were tested for the decomposition of ammonium perchlorate.

Preparation of electrically conducting particles consisting of a polymer core and a metallic copper shell

Micron-sized composite particles consisting of spherical polymer cores and metallic copper shells were prepared. Basic cupric carbonate was coated on sulfonated polymer particles by pH-controlled hydrolysis of cupric nitrate. The thickness of the coating layer was controlled by the number of polymer particles. Addition of CO2 during aging increased the shell thickness. Electrically conducting particles were obtained by reduction with hydrogen of the composite particles obtained.

Crystal structure, ferromagnetostructural behavior and evidence of cooperative Jahn–Teller interactions of the complex [CuL]Cl·H 2O (L= N-glycyl-2(aminomethyl)benzimidazol), synthesized by a novel simple method of peptide bond formation.

[CuL]Cl·H 2O 1 (L= N-glycyl-2(aminomethyl)benzimidazol) compound crystallizes in the orthorhombic space group Pna2 1 with unit cell parameters a=7.140(5) A ̊ , b=17.621(5) A ̊ , c=9.941(5) A ̊ . Its structure shows that the copper(II) ion is tetra coordinated with a square planar geometry. The ligand acts as a tridentate and the chloride ion is the fourth ligand. Symmetry related units stack into helicoidal columns along the ā direction producing weakly bonded strips with dihedral angles of 2.6° between two consecutive molecular planes. UV/VIS spectrum of 1 shows one broad and weak band at 622 nm, characteristic of d–d transitions, indicative of low local Cu(II) symmetry. X band ESR spectra of 1 at 300 and 77 K are axial exchange narrow lines with g ∥=2.135 and g ⊥=2.028. However, the axial spectrum at 6.4 K shows an increment Δ g ∥=0.076(6) and Δ g ⊥=0.028(4) which suggests a cooperative Jahn–Teller interactions between complexes via the hydrogen-bonding network. Magnetic susceptibility data at 18–300 K and fitted to the modified Bleany–Bowers equation indicate a weak ferromagnetic coupling with 2J≅+17 cm −1, which is compatible with the helium temperature ESR results and with the helicoidal stacking into columns of the molecules along the a-axis with 78.9° Cu′–Cl′–Cu and 81.2° Cu′–N( 1)–Cu bonds angles. The synthesis is a novel, simple and efficient method: in aqueous conditions and heterogeneous phase with basic copper(II) carbonate, which carries out the formation of the stable peptide bond.

The verisimilitude of verdigris: a review of the copper carboxylates

Copper formates and copper acetates occur both as corrosion products on works of art and as pigments. Some of the characteristics of these compounds are reviewed, particularly in relation to their occurrence in works of art, the deterioration of associated materials, and historical pigment recipes for the preparation of verdigris [copper (II) hydroxyacetate hydrates] and related compounds. X-ray diffraction analysis is discussed at length and new sets of powder diffraction measurements are provided, for both the basic copper formates and the basic copper acetates, which represent reference data for the verdigris salts [copper (II) hydroxyacetate hydrates], not previously available as a comprehensive set of data, as no entries for them at present exist in the International Centre for Diffraction (Joint Committee on Powder Diffraction Standards) (ICDD (JCPDS)) files. The utility of this new data is reviewed and the optical characteristics of the different verdigris preparations examined. Many of the historical recipes were replicated in the laboratory, providing further insight into the complexity of these verdigris salts and their chemical constitution, some of which include the basic copper chlorides, citrates, carbonates and other copper compounds which are often difficult to identify. The chemical literature relating to the copper acetates, and some of the classical literature describing pigment preparations based on verdigris, is reviewed.

The verisimilitude of verdigris: a review of the copper carboxylates

Copper formates and copper acetates occur both as corrosion products on works of art and as pigments. Some of the characteristics of these compounds are reviewed, particularly in relation to their occurrence in works of art, the deterioration of associated materials, and historical pigment recipes for the preparation of verdigris [copper (II) hydroxyacetate hydrates] and related compounds. X-ray diffraction analysis is discussed at length and new sets of powder diffraction measurements are provided, for both the basic copper formates and the basic copper acetates, which represent reference data for the verdigris salts [copper (II) hydroxyacetate hydrates], not previously available as a comprehensive set of data, as no entries for them at present exist in the International Centre for Diffraction (Joint Committee on Powder Diffraction Standards) (ICDD (JCPDS)) files. The utility of this new data is reviewed and the optical characteristics of the different verdigris preparations examined. Many of the historical recipes were replicated in the laboratory, providing further insight into the complexity of these verdigris salts and their chemical constitution, some of which include the basic copper chlorides, citrates, carbonates and other copper compounds which are often difficult to identify. The chemical literature relating to the copper acetates, and some of the classical literature describing pigment preparations based on verdigris, is reviewed.

Crystal structure and magnetic behavior of Cu3(O2C16H23)6·1.2 C6H12. An unexpected structure and an example of spin frustration

Abstract A copper(II) carboxylate has been obtained from the reaction of basic copper carbonate, CuCO3·Cu(OH)2, with 2,4,6-triisopropylbenzoic acid. It contains a trinuclear Cu36+ core with three-fold symmetry, with each pair of copper atoms bridged by two carboxylate ligands. The Cu···Cu separations are 3.131(3) A, precluding any direct bonding. Magnetic susceptibility data from 1.8 to 380 K at 1 000 G indicate a doublet ground state, (g ≈ 2.1) between 10–50 K (μeff = 1.80 μB). Above 50 K, the magnetic moment increases to 2.69 μB at 380 K, as expected for an equilateral triangular system of CuII with antiferromagnetic interactions between spin carriers.

The Condition, after 31 Years Exposure, of Pine Stakes Treated with Ammoniacal Copper-Based Preservatives

Summary Pinus sylvestris sapwood stakes were treated with various copper–containing waterborne and oilborne preservatives and exposed in ground for 31 years at Walpeup, Australia. Most of the waterborne preservative treatments contained basic copper carbonate and one or more of the following additives: arsenic pentoxide, pyridine, sodium pentachlorophenate, tannin and benzoic, boric, chromic, salicylic and sorbic acids. Basic copper carbonate and sulphate, at 0.95 kg m−3 of copper, protected the stakes from significant subterranean termite attack at a site in Australia providing a moderate termite hazard. Three additives (arsenic pentoxide at 0.95 kg m−3, sodium pentachlorophenate at 0.93 kg m−3 and fluoride at 0.9 kg m−3) significantly improved the efficacy of basic copper carbonate when used at retentions of 1.7 to 2.0 kg m−3 of copper. The six waterborne preservative combinations that performed best (i.e. rating greater than 6.5 out of 8) against both the termite and decay hazards over the 31 year period contained basic copper carbonate (at least 1.79 kg m−3 of copper) plus arsenic pentoxide (at least 0.92 kg m−3). Three of the six combinations also contained chromic acid. The oilborne preservative combination performing best contained basic copper carbonate (1.33 kg m−3) and pentachlorophenol (6.64 kg m−3) in tall oil. A treatment containing a similar amount of pentachlorophenol in tall oil, but no basic copper carbonate was significantly less effective. Other treatments containing basic copper carbonate and pentachlorophenol in tall oil or the copper compound with sodium pentachlorophenate in oil emulsion performed well. The implications of these results for the current generation of copper-based preservatives are discussed.

Mediaeval cantorals in the Valladolid Biblioteca: FT-Raman spectroscopic study.

Raman spectroscopic studies of three mediaeval cantorals in the Biblioteca of the University of Valladolid has revealed information about the pigments used on these large manuscripts. Although executed in a simple colour palette, very pure cinnabar was used as the major colourant, offsetting the carbon black of the verses and script. A dark blue colour was achieved using a mixture of azurite (basic copper carbonate) and carbon, whereas a light blue colour was azurite alone. A grey colour was achieved using azurite, carbon particles and a calcareous 'limewash'. A yellow pigment, used sparely in the cantorals was ascribed to saffron; unusually, there was no evidence for the presence of the yellow mineral pigments orpiment, realgar and massicot. In several regions of the vellum specimens, evidence for biodeterioration was observed through the signatures of hydrated calcium oxalate. We report for the first time the Raman spectra of pigment in situ on a vellum fragment, which also shows evidence of substrate bands; comparison of black and red pigmented regions of vellum specimens has shown the presence of calcium oxalate in the black pigmented script but not in the red pigment regions, which suggests that the cinnabar in the red-pigmented regions acts as a toxic protectant for the vellum substrate against biological colonisation processes.