Relationship between copper species in solution and leaching from alkaline copper quat (ACQ) treated wood

Holzforschung ◽  
2012 ◽  
Vol 66 (4) ◽  
Author(s):  
Sedric Pankras ◽  
Paul A. Cooper ◽  
Stephen Wylie
Keyword(s):  
Copper Complexes ◽  
Treated Wood ◽  
Exchange Capacity ◽  
Molar Ratio ◽  
Complex Species ◽  
Speciation Model ◽  
Copper Leaching ◽  
Effects Of Ph ◽  
Alkaline Copper Quat ◽  
Solution Formulation

Abstract The effects of pH and Cu:Mea ratio in alkaline copper quat (ACQ) solution formulation on the distribution of copper-monoethanolamine (Cu-Mea) complex species and Cu precipitation, and its influence on copper leaching from treated southern pine samples were investigated. Distribution of Cu in ACQ solution was studied by means of an equilibrium speciation model for aqueous systems (MINTEQA2). Conditions that favored a higher proportion of monovalent cationic complex, [Cu(Mea)2-H]1+, and precipitated copper as CuCO3(s), resulted in higher leach resistance in treated wood compared to conditions that favored the neutral copper complexes, [Cu(Mea)2-2H]0, and higher ligand copper complexes, [Cu(Mea)3]2+, [Cu(Mea)4]2+. Monovalent cationic Cu complex is maximized at a pH close to 9 with a Cu:Mea molar ratio of 1:4. Amounts of Cu leached at pH 9 were low compared to those at pH 12, where most of the Cu is present as neutral complex. Reduction of pH from 9 to 8 did not reduce Cu leaching, because of the lower cation exchange capacity of wood at the lower pH. Changing the Cu:Mea molar ratio to 1:3 at pH 9 significantly reduced the higher ligand complexes in the formulation and resulted in the majority of the copper being distributed as monovalent cationic complexes and some CuCO3(s) precipitation. These changes in 1:3 formulation significantly reduced copper leaching compared to Cu:Mea ratios of 1:4 and 1:10.

Effect of ammonia addition to alkaline copper quaternary wood preservative solution on the distribution of copper complexes and leaching

Holzforschung ◽  
2012 ◽  
Vol 66 (3) ◽  
Author(s):  
Sedric Pankras ◽  
Paul A. Cooper
Keyword(s):  
Copper Complexes ◽  
Treated Wood ◽  
Wood Preservative ◽  
Exchange Capacity ◽  
Lower Amount ◽  
Divalent Copper ◽  
Copper Leaching ◽  
Ammonia Addition ◽  
Alkaline Copper Quaternary ◽  
High Ligand

Abstract The effects of ammonia (NH3) addition to monoethanolamine (Mea)-based alkaline copper quaternary (ACQ) on the predicted distribution of cupric (Cu2+) species in solution and copper leaching from treated wood were investigated. Addition of ammonia in higher proportions reduced the amount of neutral copper-Mea complex at high pH and increased the amounts of divalent copper-NH3 complexes. At lower pH, the amounts of high-ligand copper-Mea complexes were reduced. These effects should promote better fixation and diminish copper leaching. However, ammonia addition also reduced the monovalent copper-Mea complex and the amount of copper fixed by precipitation at lower pH. This effect could, potentially, reduce fixation and leach resistance. Ammonia addition to the ACQ formulation from a Cu:Mea:NH3 ratio of 1:4:0 (normal Mea formulation, pH=9) to 1:4:2 (pH 10–10.2) and 1:4:4 (pH 10.4–10.5) did not significantly affect the amount of copper leached. However, a further increase in ammonia to 1:4:6 (pH 10.6–10.7) resulted in a significant reduction in copper leaching. At pH 9, an increase in the proportional amount of ammonia increased the amount of copper leached by reducing the amount of monovalent copper-Mea complex and increasing the divalent copper-NH3 complexes. Ammonia addition with a lower amount of Mea, 1:2.5:4 formulation (pH 10.5–10.7), significantly reduced copper leaching as a result of higher amounts of divalent copper-NH3 complexes adsorbed at higher pH (higher cation exchange capacity) without compromising the amount of copper precipitated at lower pH.

The effects of pH on copper leaching from wood treated with copper amine-based preservatives

Holzforschung ◽  
2020 ◽  
Vol 74 (9) ◽  
pp. 891-897
Author(s):  
Jeong-Joo Oh ◽  
Gyu-Hyeok Kim
Keyword(s):  
Photoelectron Spectroscopy ◽  
Treated Wood ◽  
Brown Rot ◽  
Wood Preservative ◽  
Radiata Pine ◽  
Practical Applications ◽  
Copper Loss ◽  
Effects Of Ph ◽  
Alkaline Copper Quat ◽  
Copper Amine

AbstractAs pH of leaching medium is an important factor in the leaching of wood preservative components, its effects on leaching should be quantified to ensure environmentally safe use of treated wood. In this study, the effects of pH on leaching of copper from wood treated with copper amine-based preservatives [alkaline copper quat (ACQ)-2, bis-(N-cyclohexyldiazeniumdioxy)-copper (CuHDO)-3, and copper azole (CUAZ)-3] were evaluated in comparison with wood treated with chromated copper arsenate (CCA)-3. Radiata pine sapwood blocks treated with these preservatives were leached at five pH levels (3.0, 3.5, 4.0, 4.5, and 6.5). The leached blocks were subjected to laboratory-scale decay tests using two brown-rot fungi. The blocks treated with copper amine-based preservatives leached significant amounts of copper at pH levels below 4.0. At all pH levels, the CuHDO-3-treated samples generally leached the most copper, followed by the samples treated with ACQ-2, CUAZ-3, and CCA-3. When the treated blocks were leached at pH 3.0, the degradation of hemicelluloses, which can chemically adsorb copper, was confirmed through Fourier transform infrared attenuated total reflectance (FTIR-ATR) analysis. Moreover, X-ray photoelectron spectroscopy (XPS) analysis indicated that the ratio of precipitates of the remaining copper in the treated wood severely decreased after leaching at pH levels below 4.0. Subsequent reduction in the biological effectiveness of wood treated with copper amine-based preservatives was not hardly observed after leaching at pH levels 4.0 or above. These results indicate that copper loss at pH levels 4.0 or above is not great enough to cause public concern about environmental problems and reduction of biological efficacy in practical applications.

Consideration on modeling of Nb sorption onto clay minerals

2020 ◽  
Vol 108 (11) ◽  
pp. 873-877
Author(s):  
Tetsuji Yamaguchi ◽  
Saki Ohira ◽  
Ko Hemmi ◽  
Logan Barr ◽  
Asako Shimada ◽  
...  
Keyword(s):  
Distribution Coefficient ◽  
Clay Minerals ◽  
Safety Assessment ◽  
Distribution Coefficients ◽  
Surface Species ◽  
Complex Species ◽  
Intermediate Depth ◽  
Speciation Model ◽  
Surface Phases ◽  
High Distribution Coefficient

AbstractSorption distribution coefficient (Kd) of niobium-94 on minerals are an important parameter in safety assessment of intermediate-depth disposal of waste from core internals etc. The Kd of Nb on clay minerals in Ca(ClO4)2 solutions were, however, not successfully modeled in a previous study. The high distribution coefficients of Nb on illite in Ca(ClO4)2 solutions were successfully reproduced by taking Ca–Nb–OH surface species into account. Solubility of Nb was studied in Ca(ClO4)2 solutions and the results were reproduced by taking an aqueous Ca–Nb–OH complex species, CaNb(OH)6+, into account in addition to previously reported Nb(OH)6− and Nb(OH)72−. Based on this aqueous speciation model, the Ca–Nb–OH surface species responsible for the sorption of Nb on illite in Ca(ClO4)2 solutions was presumed to be X_OCaNb(OH)6. Although uncertainties exist in the speciation of aqueous Ca–Nb–OH species, the result of this study proposed a possible mechanism for high distribution coefficient of Nb on illite in Ca(ClO4)2 solutions. The mechanism includes Ca–Nb–OH complex formation in aqueous, solid and surface phases.

Effects of pH and ionic strength on the cation exchange capacity of soils with variable charge

Soil Research ◽  
1981 ◽  
Vol 19 (1) ◽  
pp. 93 ◽  
Author(s):  
GP Gillman
Keyword(s):  
Ionic Strength ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Surface Soils ◽  
Ph Values ◽  
Variable Charge ◽  
Effects Of Ph ◽  
Variable Charge Soils

The cation exchange capacity of six surface soils from north Queensland and Hawaii has been measured over a range of pH values (4-6) and ionic strength values (0.003-0.05). The results show that for variable charge soils, modest changes in electrolyte ionic strength are as important in their effect on caton exchange capacity as are changes in pH values.

Appearance, corrosion properties, and leach resistance of spruce and pine wood treated with Mea modified micronized copper preservative (MCu)

Holzforschung ◽  
2014 ◽  
Vol 68 (4) ◽  
pp. 477-486 ◽  
Author(s):  
Myung Jae Lee ◽  
Sedric Pankras ◽  
Paul Cooper
Keyword(s):  
Wood Species ◽  
Wood Preservative ◽  
Molar Ratio ◽  
Corrosion Properties ◽  
Pine Wood ◽  
Molar Ratios ◽  
Copper Leaching ◽  
Mold Resistance ◽  
Refractory Wood

Abstract Canadian refractory wood species treated with micronized copper (MCu) wood preservative become mottled and streaky in appearance. To overcome this issue, the MCu system was modified by adding small amounts of monoethanolamine (Mea). The modified systems were evaluated to clarify the role of Mea in terms of leaching, corrosion, and mold resistance of MCu systems. The mottled and streaky surface on treated spruce was prevented at Mea/Cu molar ratios between 0.7 and 1.5. Copper leaching remained modest and was only slightly higher than that of MCu alone up to a Mea/Cu molar ratio of 1.2. However, adding even a small amount of Mea to the MCu formulation increased fastener corrosion compared with MCu. Protonated Mea increased as more Mea was added and was identified as the main corrosion-causing electrolyte in the system.

scholarly journals Synthese und Struktur diastereomerer, zweikerniger Kupferkomplexe [1] / Synthesis and Structure of Diastereomerie Dinuclear Copper Complexes [1]

1994 ◽  
Vol 49 (10) ◽  
pp. 1410-1414 ◽  
Author(s):  
Rolf W. Saalfrank ◽  
Oliver Struck ◽  
Karl Peters ◽  
Hans Georg von Schnering
Keyword(s):  
Structure Analysis ◽  
Copper Complexes ◽  
Molar Ratio ◽  
Dinuclear Copper ◽  
X Ray ◽  
Dark Green ◽  
2D Polymer ◽  
Light Green

Abstract Depolymerisation of a copper(II)/pyrrolidine-based 2D -polymer 2 by 4,4′-bipyridyl [molar ratio: 2 (CuL2) : 1 (Bipy)] and recrystallisation of the reaction product leads to two visually distinguishable crystal charges, composed of dark green octahedra meso-4 and light green rod-shaped crystals racem-5. Separation of the conglomerate of the morphologically different crystals is accomplished by pick out. The structure of the dinuelear complex racem-5 has been established unambigously by X-ray structure analysis. EPR and susceptibility measurements of mixtures of complex meso-4 and racem-5 indicate that there is no interaction be­tween the two copper(II) centres.

scholarly journals Preparation and Study of Sulfonated Co-Polynaphthoyleneimide Proton-Exchange Membrane for a H2/Air Fuel Cell

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5297
Author(s):  
Ulyana M. Zavorotnaya ◽  
Igor I. Ponomarev ◽  
Yulia A. Volkova ◽  
Alexander D. Modestov ◽  
Vladimir N. Andreev ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Proton Exchange Membrane ◽  
Maximum Output Power ◽  
Exchange Capacity ◽  
Proton Exchange ◽  
Molar Ratio ◽  
Disulfonic Acid ◽  
Membrane Electrode ◽  
Maximum Output ◽  
Practical Applications

The sulfonated polynaphthoyleneimide polymer (co-PNIS70/30) was prepared by copolymerization of 4,4′-diaminodiphenyl ether-2,2′-disulfonic acid (ODAS) and 4,4’-methylenebisanthranilic acid (MDAC) with ODAS/MDAC molar ratio 0.7/0.3. High molecular weight co-PNIS70/30 polymers were synthesized either in phenol or in DMSO by catalytic polyheterocyclization in the presence of benzoic acid and triethylamine. The titration reveals the ion-exchange capacity of the polymer equal to 2.13 meq/g. The membrane films were prepared by casting polymer solution. Conductivities of the polymer films were determined using both in- and through-plane geometries and reached ~96 and ~60 mS/cm, respectively. The anisotropy of the conductivity is ascribed to high hydration of the surface layer compared to the bulk. SFG NMR diffusometry shows that, in the temperature range from 213 to 353 K, the 1H self-diffusion coefficient of the co-PNIS70/30 membrane is about one third of the diffusion coefficient of Nafion® at the same humidity. However, temperature dependences of proton conductivities of Nafion® and of co-PNIS70/30 membranes are nearly identical. Membrane–electrode assemblies (MEAs) based on co-PNIS70/30 were fabricated by different procedures. The optimal MEAs with co-PNIS70/30 membranes are characterized by maximum output power of ~370 mW/cm2 at 80 °C. It allows considering sulfonated co-PNIS70/30 polynaphthoyleneimides membrane attractive for practical applications.

Electron Paramagnetic Resonance Spectroscopic (EPR) Study of Copper Amine Treated Southern Pine in Wood Preservation

Holzforschung ◽  
2000 ◽  
Vol 54 (4) ◽  
pp. 343-348 ◽  
Author(s):  
J. Zhang ◽  
D. P. Kamdem
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Copper Complexes ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Treated Wood ◽  
Wood Preservation ◽  
Resonance Spectroscopy ◽  
Paramagnetic Resonance ◽  
Electronic Parameters ◽  
Electron Paramagnetic ◽  
Copper Amine

Summary The structure of copper complexes in copper amine treated wood samples were elucidated by the application of electron paramagnetic resonance spectroscopy (EPR). EPR axial spectra were observed for all Cu-amine treated samples irrespective of the formulations. The values of A∥ and g∥ of the axial spectra indicate that the stereo-structure of copper complexes in copper amine treated wood was either tetragonal-based octahedral or square-based pyramidal. Comparison of electronic parameters of A∥ and g∥ in Cu-amine treated wood with those of the Cu-amine treating solution and the values in literature suggests that the interaction of wood with copper amine is through complexation in which wood functional groups are complexed with copper amine perpendicularly. The copper complexes in both treating solution and treated wood are in the form of CuN2O2, where copper is ligated with 2 nitrogen and 2 oxygen.

scholarly journals Effects of pH and Ca/P molar ratio on the quantity and crystalline structure of calcium phosphates obtained from aqueous solutions

2009 ◽  
Vol 89 (3-4) ◽  
pp. 301-316 ◽  
Author(s):  
Omar Mekmene ◽  
Sophie Quillard ◽  
Thierry Rouillon ◽  
Jean-Michel Bouler ◽  
Michel Piot ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Crystalline Structure ◽  
Calcium Phosphates ◽  
Molar Ratio ◽  
Effects Of Ph

scholarly journals Peroxide Post-Treatment of Wood Impregnated with Micronized Basic Copper Carbonate

Coatings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1213
Author(s):  
Rod Stirling ◽  
Gabrielle Boivin ◽  
Adnan Uzunovic ◽  
Stacey Kus ◽  
John N. R. Ruddick
Keyword(s):  
Color Change ◽  
Treated Wood ◽  
Post Treatment ◽  
Fungal Resistance ◽  
Copper Carbonate ◽  
Photo Degradation ◽  
Color Changes ◽  
Copper Leaching ◽  
The Impact ◽  
Increased Susceptibility

Wood is vulnerable to significant color changes when used in exterior applications. Some copper-based wood preservatives use colorants to minimize this color change. This paper examines the ability of a peroxide post-treatment to turn wood impregnated with micronized basic copper carbonate (CuCO3·Cu(OH)2) (MBCC) a stable brown color. MBCC-treated wood, with and without peroxide post-treatment, along with associated controls were evaluated for color change, erosion and black-stain fungal resistance after exposure to artificial photo-degradation. The impact of the peroxide treatment on copper leaching was assessed in a laboratory experiment, and the impact on copper reactivity was assessed by electron parametric resonance (EPR) spectroscopy. Peroxide post-treatment of wood pressure impregnated with MBCC was shown to reduce color change by more than 50% compared to controls. Erosion due to photo-degradation and colonization by black-stain fungi were lower in samples treated with MBCC than in untreated controls and were relatively unaffected by peroxide post-treatment. The peroxide post-treatment was associated with increased amounts of mobile copper. This led to increased susceptibility to leaching and to a more than 60% increase in the amount of copper than had reacted with the wood.

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