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.

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.

Prediction of long-term leaching potential of preservative-treated wood by diffusion modeling

Holzforschung ◽  
2005 ◽  
Vol 59 (5) ◽  
pp. 581-588 ◽  
Author(s):  
Levi Waldron ◽  
Paul A. Cooper ◽  
Tony Y. Ung
Keyword(s):  
Diffusion Coefficient ◽  
Treated Wood ◽  
Free Water ◽  
Wood Preservative ◽  
Copper Component ◽  
Equilibrium Dissociation ◽  
Disodium Octaborate Tetrahydrate ◽  
Alkaline Copper Quaternary ◽  
Copper Azole ◽  
Copper Amine

Abstract An approach to modeling leaching and leaching impacts of preservative components from treated wood is presented based on three simple laboratory determinations: the amount of preservative component available for leaching (Le), equilibrium dissociation of preservative into free water in wood (Di) and diffusion coefficients for component leaching in different wood directions (D). In this study, the following inorganic wood preservative systems were investigated: chromated copper arsenate (CCA), the copper component of copper azole (CA) and alkaline copper quaternary (ACQ), and boron in disodium octaborate tetrahydrate (DOT). Aggressive leaching of finely ground wood showed that amounts of preservative compounds available for leaching were highest for borates, followed by copper in copper amine systems and arsenic in CCA, copper in CCA and chromium in CCA. The equilibrium dissociation or solubility of components in free water in the wood was much higher for borates and copper amine, followed by copper and arsenic in CCA and chromium in CCA. Use of the applicable diffusion coefficient (D) and Di or Le values in a diffusion model allows the prediction of total amount leached and emission or flux rate at different times of exposure for products with different dimensions and geometries. The approach was tested and generally validated through application of the model to results of laboratory water spray leaching of full-size lumber samples. The approach explains the rapid leaching of boron compounds (large diffusion coefficient and high initial dissociated concentration) compared to other preservative components and predicts that ACQ will have higher initial leaching rates compared to CCA and CA, but the latter preservatives will continue to leach copper at a measurable rate for a much longer time. The practical implications and limitations of the approach are discussed.

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 Enhancement of Wood Biological Resistance and Fire Retardant Properties after Laccase Assisted Enzymatic Grafting

Forests ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1102
Author(s):  
Cristian Bolaño ◽  
Sabrina Palanti ◽  
Luigi Benni ◽  
Diego Moldes
Keyword(s):  
Silver Nanoparticles ◽  
Flame Retardant ◽  
Toxic Substance ◽  
Treated Wood ◽  
Fire Retardant ◽  
Wood Preservative ◽  
Decay Resistance ◽  
Kraft Lignin ◽  
Fire Retardant Properties ◽  
Wood Surfaces

Several treatments of wood, based on laccase assisted grafting, were evaluated in this paper. Firstly, the efficacy of lignosulfonate and kraft lignin from Eucalyptus spp. as a wood preservative was assessed. Both ligno products were anchored to wood surfaces via laccase treatment in order to avoid leaching. Moreover, some of these wood preservative treatments were completed with the addition of silver nanoparticles. For comparison, a commercial product was also analyzed in terms of its fungal decay resistance during surface application, in accordance to use class 3, CEN EN 335. Secondly, the anchoring of a flame retardant based on tetrabromobisphenol-A (TBBPA) was attempted, to limit the dispersion of this toxic substance from treated wood. In both cases, kraft lignin and lignosulfonate showed an improvement in wood durability, even after leaching. However, the addition of silver nanoparticles did not improve the efficacy. On the other hand, the efficacy of TBBPA as a flame retardant was not improved by grafting it with laccase treatment or by adding O2, a co-factor of laccase.

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 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.

Effect of Polyvinyl Alcohol on Copper Leaching from Treated Wood

2009 ◽  
Vol 59 (10) ◽  
pp. 28-30
Author(s):  
P. Vasishth ◽  
D. D. Nicholas ◽  
W. P. Henry ◽  
T. P. Schultz
Keyword(s):  
Polyvinyl Alcohol ◽  
Treated Wood ◽  
Copper Leaching

Determination of the accessible hydroxyl groups in heat-treated Styrax tonkinensis (Pierre) Craib ex Hartwich wood by hydrogen-deuterium exchange and 2H NMR spectroscopy

Holzforschung ◽  
2007 ◽  
Vol 61 (5) ◽  
pp. 488-491 ◽  
Author(s):  
Le Xuan Phuong ◽  
Masato Takayama ◽  
Satoshi Shida ◽  
Yuji Matsumoto ◽  
Tetsuo Aoyagi
Keyword(s):  
Nmr Spectroscopy ◽  
Treated Wood ◽  
Deuterium Exchange ◽  
Fungal Resistance ◽  
Lower Amount ◽  
Hydroxyl Groups ◽  
Hydrogen Deuterium Exchange ◽  
Oh Groups ◽  
Heat Treated ◽  
Hydrogen Deuterium

Abstract A new approach based on hydrogen-deuterium exchange is proposed for measuring accessible OH groups in wood. The deuterium (D) exchanged for hydrogen in OH groups in wood was converted to D2O by combustion in oxygen gas then diluted in deionized water, and subsequently determined by 2H NMR spectroscopy. The amount of accessible OH groups in Styrax tonkinensis wood is approximately 6.8 mmol g-1. This measurement is very accurate, with an error of approximately 0.2 mmol g-1. Heat-treated wood has a lower amount of accessible OH groups than non-treated wood. This finding is in agreement with the decreased hygroscopicity of heat-treated wood and explains, at least partially, its increased fungal resistance.

Conjugated Polyrotaxanes Incorporating Mono- or Divalent Copper Complexes

1999 ◽  
Vol 38 (19) ◽  
pp. 4203-4210 ◽  
Author(s):  
Pierre-Louis Vidal ◽  
Bernadette Divisia-Blohorn ◽  
Gérard Bidan ◽  
Jean-Marc Kern ◽  
Jean-Pierre Sauvage ◽  
...  
Keyword(s):  
Copper Complexes ◽  
Divalent Copper
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