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Copper to quat ratio in alkaline copper quat (ACQ) wood preservative - Effects on fixation and leaching of preservative components in red pine
2009 - IRG/WP 09-30496
This study investigates the effect of the relative proportion of copper oxide (CuO) to didecy dimethyl ammonium carbonate (DDACb) in an alkaline copper quat (ACQ) formulation on the rate of copper fixation or stabilization and the resistance of treated wood to leaching of copper and quat (DDACb). Red pine samples were treated with ACQ, having CuO to DDACb ratios of 2:1 (the normal ratio for ACQ-D), 1:1 and 1:2, at concentrations of 0.6%, 1% and 1.5%. Treated samples were wrapped in plastic and post treated at 500C. Samples were squeezed to express solution, which was analyzed for copper to measure the percentage copper fixed at different times during post treatment conditioning. Conditioned samples were subjected to AWPA E11 laboratory leaching experiments and the amounts of copper and DDACb leached from the samples were analyzed. A decrease in relative proportion of copper in the ACQ formulation from a CuO to DDACb ratio of 2:1 to 1:1 and 1:2 resulted in a substantial reduction in the time required for the fixation of copper. There was a significant decrease in the amount of copper leached from the species studied with reduction of relative proportion of copper in the ACQ formulation. The reduction in leaching was higher for samples treated with concentrations of 1% and 1.5% ACQ compared to the sample treated with 0.6% ACQ. Formulation having 1:1 CuO to DDAC ratio appears to be the most promising, considering the positive effects of reduced copper ratio on copper leaching and fixation time and the minimal effect on DDAC leaching.
S Pankras, P A Cooper, T Ung, L Awoyemi
Laboratory evaluation of borate amine: Copper derivatives in wood for fungal decay
2010 - IRG/WP 10-30543
The aims of this study were to evaluate borate: amine: copper derivatives in wood for fungal decay protection as well as the permanence of copper and boron in wood. Wood treated with each of four derivatives of borate:amine:copper prevented fungal decay. Disodium tetraborate ecahydrate (Borax):amine:copper derivatives with retentions of 0.61 to 0.63% after water leaching prevented decay by Gloeophylum trabeum (Gt) and 0.64% by Trametes versicolor (Tv). Leaching did not decrease decay resistance to both Gt and Tv. Disodium octaborate tetrahydrate(DOT):amine:copper derivatives with retentions of 1.14 to 2.93% after water leaching prevented decay by Gt and 0.54 to 1.19 % by Tv. Leaching decreased decay resistance to Gt but not to Tv. Higher copper and boron in disodium borax:amine:copper derivatives contributed to more decay resistance to Gt and Tv than that of DOT:amine:copper derivatives as evidenced by elemental analysis. Infrared spectra (IR ) of wood treated with 5% borate: amine: copper derivatives after water leaching showed that increased absorption at 1632-1635 cm-1 compared with the control. The increased absorption at 1632-1635 cm-1 was partly attributable to carbonyl of copper carboxylates from oxidation of hemiacetals of hemicelluloses and cellulose by copper (II) ions, and carbonyls of copper (II) quinone methides by oxidation of guaicyls by copper (II) ions. It was also partly attributable to carbonyls of copper carboxylates from hemicelluloses and phenolates from lignin through ion exchange reactions. The above oxidation and ion exchange reactions of copper with wood components may account for their efficacy and long term performance.
Influence of different fixation and ageing procedures on the leaching behaviour of copper from selected wood preservatives in laboratory trials
2003 - IRG/WP 03-20264
The paper focuses on the role of different parameters, such as fixation, sample size, wood species, and leaching in internationally standardized ageing procedures for wood preservatives from Europe, Japan and the United States. The leaching protocols used were EN 84, JIS K 1571 and AWPA E11 protocols. The wood species were Scots pine, Sugi and Southern Yellow Pine respectively. Three types of commercially important copper-based wood preservatives were used as model formulations, namely copper/copper-HDO, ammoniacal copper/quat and CCA. The most important factors determining the extent of copper leaching in the different lab trials were the sample size (volume/surface ratio) and the fixation conditions prior to leaching. On the other hand, the wood species and the leaching protocol itself were found to have only minor influence on the copper leaching rate in the test methods included in this study.
J Habicht, D Häntzschel, J Wittenzellner
Problems of fixation of CCA-preservatives in palm-wood
1985 - IRG/WP 3338
Palm-wood may be used for posts and poles where it needs proper treatment for long time use. Based on observations by W. Killmann on low CCA-fixation in palm-wood, samples of Jubaea-palm grown in a Greenhouse at Hamburg, have been treated in two different series with a 4% solution of CCA-type B. After 1-16 weeks of storage the blocks were split into sticks of 1-2 mm² and leached. In all series 50% of the chromium and copper content of the individual blocks was leached independent of the time of storage, whereas simultaneously treated pinewood samples showed complete fixation after 4 weeks of storage.
H Willeitner, K Brandt
Copper binding capacity of modified wood flour
1992 - IRG/WP 92-3709
Wood flour was modified by reaction with oxidising agents and CCA preservative. The copper chromium and arsenic were removed from the CCA treated wood flour by an acid leaching procedure. The modified wood flours were allowed to react with copper acetate solution and the level of copper fixation achieved was determined. The modified wood flours had greater affinity for copper ions present in solution than unmodified wood flour.
N C Milowych, W B Banks, J A Cornfield
Literature survey on the permanence and distribution of salt-type wood preservatives
1969 - IRG/WP III 1B
The objective of this survey is generally to review some of the more important published work dealing with the distribution and permanence of salt-type waterborne wood preservatives in treated timber. The survey is limited to the major chrome-containing formulations and the classification system proposed by Becker (1964) has been adopted throughout. CK - chromium, copper (copper, chrome); CKA - chromium, copper, arsenic (copper, chrome, arsenate); CKB - chromium, copper, boron (copper, chrome, boron); CFK - chromium, fluorine, copper (copper, chrome, fluorine); CFA - chromium, fluorine, arsenic (fluor, chrome, arsenate); CF - chromium, fluorine (fluor, chrome). The literature compilation covers the performance of these preservatives assessed from laboratory tests, field tests and practical experience; their application and distribution in the treated wood; and their influence on materials such as glues, paints or metals and the wood itself. It is not the purpose of this survey to draw conclusions regarding the relative merits of the various formulations, the choice of a formulation in a given situation depending upon many factors outside the terms of reference of this review, and not all of a technical nature. In general, there is insufficient directly comparable data for a definitive assessment and in the few comparisons available special factors frequently apply.
Contribution of wood components on the absorption of copper amine
2000 - IRG/WP 00-30216
The contribution of wood components on the absorption of copper amine was investigated. Holocellulose, lignin and xylan absorbed significant amount of copper. The amount of copper absorbed by cellulose was almost negligible. The removal of extractive also decreased the amount of copper absorption. This study clearly indicates the importance of lignin, hemicellulose in the absorption of copper amine in wood.
D P Kamdem, Jun Zhang
EPR investigations of interactions between ammoniacal Cu(II) octanoate and wood
1996 - IRG/WP 96-30110
Ammoniacal solutions of copper(II) octanoate [ C u . h l f . 2 . r h l f.(O2CC7H15)4], interactions of these solutions with wood and wood components, and leaching of copper(II) octanoate from impregnated wood samples, have been studied by electron paramagnetic resonance (EPR) method. It is still not clear if in the Cu(II) octanoate - water - ammonia system, Cu(II) remains in a (copper(II) octanoate - ammonia) complex. The majority of leached Cu(II) with distilled water and a solution simulating acid precipitations was washed out in the first five hours of leaching procedure (up to 35% of initial Cu(II)). Time dependence studies of interactions of ammoniacal Cu(II) octanoate with wood, cellulose and brown rotted lignin showed, that the fastest and most significant was the reaction with lignin. Cu(II) is immobilised also on cellulose. A significant contribution of ammonia evaporation to the fixation mechanism of the preservative was observed as well.
F Dagarin, M Petric, F Pohleven, M Sentjurc
The course of fixation of Cu-Cr-As wood preservatives
1972 - IRG/WP 307
Copper-chrome-arsenic (CCA) preservatives in contact with wood result in an instant extensive increase of pH, because of ion-exchange and adsorption reactions with the wood. During precipitation of the active elements the pH continuously increases but reaches a maximum, when all chrome is consumed. Some of the early reaction products are unstable and slowly convert via dissolution into stable compounds. The conversion proceeds by proton liberating as well as proton consuming reactions. The pH therefore alternatively decreases and increases until the reactions cease after several months. The final equilibrium fixation products are: ion-exchange fixation of Cu to the wood CrAsO4, Cu(OH)CuAsO4 and Cr(OH)3. The chrome fixation is 2nd order with respect to hexavalent chrome in the liquid phase, four regions with distinct chrome fixation rate constants were found. A hypothesis is given for the mechanism of fixation.
Fixation of chromated copper arsenate (CCA) wood preservative in Australian hardwoods: A comparison of three Eucalyptus species
1996 - IRG/WP 96-30107
New environmental guidelines for the management of CCA treatment plants were released in Australia in 1995. This has stimulated interest in techniques for controlling or accelerating the fixation of CCA in freshly treated timber products. The ability to understand, then effectively control and/or accelerate fixation of CCA in treated timber products can be an economic, technical and environmental advantage. Data available on fixation of CCA in timber commodities however, is mainly on softwood not hardwood species. In this paper, the rate of fixation of CCA Type C Oxide in poles of three species of Australian Eucalyptus was monitored over a six week period following treatment. These results will assist in the design of adequate drip pad and undercover storage area for pole treaters in South East Queensland.
Leaching Characteristics of Copper in Copper Treated Wood
2003 - IRG/WP 03-30316
The leaching characteristics of copper in copper treated bamboo and other wood species such as slash pine and poplar has been conducted in this paper according to AWPA M11-87 standard, the result indicates that: --Copper fixation rate of salts from organic acids such as citrate and oxalate and malate is less than other non-organic acid formulations. --Copper fixation rate of oven-dried bamboo samples is less than air-dried bamboo samples for all formulations containing copper. --Copper fixation rate of bamboo treated with ACQ containing dimethyl didecyl ammonium chloride (DDAC) is higher than other type of ACQ formulation containing benzalkonium chloride. Copper fixation rate of ammonia-based ACQ-B treated bamboo is higher than amine-based ACQ-D while in the same retention level. --Copper fixation rate in some formulations containing phosphate is higher than non-phosphate ones.
Mingliang Jiang, Junliang Liu, Daochun Qin, Yamei Wang, Zehui Jiang
Determination of fixation properties by bioassays - A proposal for the assessment of safety indexes in wood protection
1990 - IRG/WP 3566
In the determination of environmental effects of chemicals tests with fishes, daphnia and algae have proved to be practicable. With respect to wood protection such bioassays are suitable to control effects of treated timber against aquatic organisms. By using the fish-acute-toxicity-test the development of a laboratory test method is described for the checking of the fixation rate of a copper-chromium wood preservative. By this the importance of the observation of a proper fixation period is demonstrated for the use of treated wood in water contact. Estimating ecotoxicological effects of leachable compounds using sensitive bioindicators allows a differentiated determination of environmental risks of impregnated timber. The comparison with the toxic effects of the compounds of a wood preservative are a first step in the assessment of safety indexes in wood protection.
Leaching and fixation characteristics of chrome-copper-fluoride-zinc (CCFZ) treated wood
1996 - IRG/WP 96-30096
The leaching characteristics of radiata pine sapwood blocks treated with CCFZ were evaluated by the AWPA standard leaching test. The rate of fixation of the preservative components in CCFZ treated radiata pine were also evaluated by quantitative analysis of solution expressed from the treated wood. Both leaching and fixation characteristics of CCFZ were compared with CCA-Type C treated wood samples. The permanence of CCFZ is excellent and comparable to that of CCA-Type C, and the rates of CCFZ fixation were similar to those found for CCA-Type C. These results suggest that CCFZ has a potential as alternative preservative for the replacement of CCA-Type C.
Gyu-Hyeok Kim, Jong-Bum Ra
Applications of the shower test. Part B: Results from CC and CCB treated wood: influence of fixation process
1993 - IRG/WP 93-50010
This report outlines the results of shower tests conducted on CC and CCB treated wood. The results indicate the fairly good fixation of chromium and the reasonable fixation of copper in CC and CCB formulations, as judged by the leaching limits within the Environmental Regulations. In general boron leaches to a higher extent than chromium and copper. The shower test has proven to be a useful quality control and research test. It determines reasonably accurately the leaching under simulated conditions and, admittedly from a limited number of tests, it can determine differences between various fixation cycles. Natural fixation, controlled climate room fixation and steam fixation were compared. Overall the sleam fixation process gave the lowest leaching figures although the selection of an appropriate fixation facility is a question for individual companies, taking into account capital, customer base, throughput etc.
W J Homan, H Militz
A comparison of the leaching resistance of diammine-copper complexes and copper carbonate precipitated in wood
1997 - IRG/WP 97-30158
Previous studies have shown that during treatment of wood with ammoniacal copper solutions, both simple copper precipitates and diammine-copper complexes are formed. The objective of the present study is to determine the relative importance of both forms of copper, on such aspects as preservative leachability and biological performance. In the current experiment, the leachability of copper carbonate precipitated in wood is compared with that of diammine-copper complexes. The results confirmed that both forms of copper resisted leaching by distilled water. However, when exposed to the more aggressive leaching conditions using the sodium citrate buffered solution, the diammine-copper complexes were significantly more ressistant to removal from the wood. Further studies are planned to examine the diammine-copper complexes present in the wood as well as the efficacy of these complexes against wood decay fungi.
Xiao Jiang, J N R Ruddick
Determination of ethanolamine in impregnated wood
2000 - IRG/WP 00-20198
Leaching of copper based preservatives from wood is usually prevented by adding chromium compounds to copper containing formulations. It seems that suitable substitutes for chromium fixation agents may be amines. In this paper, we report our results on interactions between copper(II) octanoate and ethanolamine (C2H7NO, 2-aminoethanole) with wood or its components. A part of ethanolamine from a wood preservative chemically reacts with wood and does not evaporate from it. This can be seen from retentions and from the changes of FTIR spectra of treated wood. We assume that ethanolamine mainly reacts with hemicelluloses and lignin complex. The unevaporated part of ethanolamine is even higher (for 2%) in the presence of copper(II) octanoate. We think that this difference originates from ethanolamine, which is complexed to copper(II) octanoate. Ethanolamine in wood can be easily determined with the indicator bromphenol blue in ethanol/acetic acid aqueous solution. Wood with ethanolamine turns blue while wood without ethanolamine remains yellow.
M Humar, M Petric
Applications of the shower test. Part A: Results from CCA type C treated wood: influence of fixation process
1993 - IRG/WP 93-50009
This report outlines the results of shower tests conducted on CCA type C treated wood. The results indicate the inherent good fixation of CCA type C, as judged by the leaching limits within the Environmental Regulations. The shower test has proven to be a useful quality control and research test. It determines reasonably accurately the leaching under simulated conditions and, admittedly from a limited number of tests, it can determine differences between various fixation cycles. Natural fixation, controlled climate room fixation and steam fixation were compared. Overall the steam fixation process gave the lowest leaching figures although the selection of an appropriate fixation facility is a question for individual companies, taking into account capital, customer base, throughput etc.
W J Homan, H Militz, D A Lewis
Incomplete fixation of chromium in the pre-treated wood with a solution of copper and arsenic compounds
1995 - IRG/WP 95-50052
Ponderosa pine wood thin sections were treated with a combination of chromium, copper, and arsenic chemicals. The wood sections was analyzed by electron spin resonance spectrometry (ESR) and X-ray photoelectron spectrometry (XPS) to elucidate the mechanism of fixation of the chromated-copper preservatives. The wood subjected to the two-step treatment with copper and arsenic followed by chromium exhibited a strong Cr(V) ESR signal. However both Cr(III) and weak Cr(V) signals were observed in wood subjected to the one-step treatment containing chromium, copper, and arsenic. XPS spectra also supported the Cr(V) formation in the former treatment. The further chromium reduction from Cr(V) to Cr(III) for samples treated in two steps did not proceed very well during the fixation period of 3 months. Copper arsenate formed in the wood could disturb the interaction of chromium with the wood. These results indicate that re-treatment of wood with chromium containing preservatives may result in incomplete fixation of chromium.
J N R Ruddick, K Yamamoto, F G Herring, P C Wong, K A R Mitchell
Tests with ammoniacal copper and alkyl ammonium compounds as wood preservatives
1984 - IRG/WP 3299
Formulations based on copper and alkyl ammonium compounds in ammonia solution have been tested in a fungus cellar on Pinus radiata and Fagus sylvatica. This type of products gives promising results as wood preservatives, especially on hardwood and are safe to destroy by e.g. combustion. The best results were achieved with a dialkyl ammonium compound, Cu/octyldecyl dimethyl ammonium chloride (NH3). The optimal weight ratio of Cu/AAC is for Pinus radiata = 0.2-0.4 and Fagus sylvatica = 1.0 based on cost-effectiveness. Fixation and leaching of coppertetrammine are discussed in detail. The leaching of active components from the Cu/AAC/NH3-systems is very low.
A laboratory study on effect of coating materials on leaching of copper from CCA treated wood
2001 - IRG/WP 01-50176
Components of CCA preservatives can leach into surrounding soil and water and have some effect on germination and growth of some plants. In this report, the effect of coating materials in reducing chemical concentration in the leachate were evaluated. Rubber wood blocks (Hevea brasiliensis) treated with CCA were fixed at room temperature at high humidity. After air dried, they were painted with coating materials, then followed by leaching procedure. The concentration of copper in the leachate was analysed by atomic absorption spectrophotometry. The results showed that coating materials could reduced the concentration of copper in leaching water. In addition, the resistance of treated wood against destroying fungi was studied. After painted with coating materials, wood specimens were exposed to fungi for the periods of time and results were discussed.
A Veenin, T Veenin
Dimensional stabilization and decay resistance of wood treated with brown-rotted lignin and copper sulfate
1990 - IRG/WP 3608
The objective of this study was to evaluate the potential usefulness of brown-rotted lignin (BRL) as a dimensional stabilization and copper complexing agent for wood treatment. For dimensional stabilization, aqueous solutions of the lignin extract were combined with either copper sulfate, glyoxal or other additives. Anti-shrink efficiency (ASE) values as high as 42% were obtained with wood treated with a BRL/Cu combination. By treating wood with a 6% solution of the lignin extract prior to treatment with copper sulfate, a two-fold increase in fixation of copper was attained. Soil block tests were also performed on wood treated with BRL and copper sulfate individually as well as in combination; it was found that the BRL increased the activity of Cu against Poria placenta.
L Jin, D D Nicholas, T Schultz
Laboratory Evaluation and Field Trial of Chlorothalonil and Copper-based Preservatives and Leaching Performance of Copper in Copper Treated Wood
2002 - IRG/WP 02-30279
Soil block test and field trial of some Chinese plantation wood species pine and poplar treated with chlorothalonil formulations and copper-based preservatives such as ACQ-B and copper citrate (CC) were conducted. The results of soil block test indicated that chlorothalonil formulations and ACQ-B as well as CC are very effective for controlling the 2 fungi species Corious versicolor and Poria placenta at different retention. There is no significant difference of weight loss among retention level range 2.54-23.1 kg/m3 of ACQ-B and CC in our test. The durability of wood treated with chlorothalonil oil formulation is better than that of treated with emulsion formulation. ACQ-B and CC treated wood at different retention level are effectively resistant to decay and termite after 36 monthr field trial at Guangzhou, south China. Leaching rate of copper of CC treated wood is much higher than that of CCA and ACQ-B treated wood by the 2 wood species Pinus massoniana and Eucalyptus urophylla according to AWPA standard M11-87.
Mingliang Jiang, Ping Wang, Chungen Piao, Zhaobang Li, Quan Lu, Lei Liu
Oxidation of wood components during CCA-C fixation
1993 - IRG/WP 93-30024
Pre-extracted radial sections of southern yellow pine sapwood were treated with CCA-C and analyzed by X-ray photoelectron spectroscopy (XPS). The ratio of C1 (carbon bonded to carbon and/or hydrogen) to C2 (carbon bonded to one oxygen) in XPS Cls spectra was taken as a measure of the progress of oxidation of wood components during CCA fixation. This ratio was 0.82 before CCA treatment and increased to 0.85 after 10 minutes soaking, to 1.0 after 1 hour soaking and decreased to 0.5 after 3 hours soaking. Oxidation of C2 to C3 (carbon bonded to two oxygens or a carbonyl group) was demonstrated by in situ trapping of C3 with ethylene glycol as they were formed. Further oxidation of C3 to C4 (carboxylic carbon: O-C=O) was not observed in the XPS spectra, as found by others. The hypothesis that rapid decarboxylation results in loss of C4 as evolved CO2 is supported by the observation that the C4 component of untreated wood was reduced by more than 90% after 10 minutes of CCA soaking followed by accelerated fixation and by the observation of CO2 evolution during early stages of accelerated fixation. The Cr(2p) spectra of CrVI and CrIII were established at 580.2 and 577.8 eV respectively. Accelerated fixation of CCA-C treated specimens resulted in complete reduction of CrVI to CrIII.
M Kaldas, P A Cooper
Rapid fixation of Chromated Copper Arsenate (CCA) wood preservatives by microwave treatment
2000 - IRG/WP 00-40184
Rapid microwave heating of freshly chromated copper arsenate (CCA) treated timber indicates that rapid preservative fixation is possible within approximately 40 seconds. The leaching of CCA was evaluated using simulated rainfall. Cost analyses indicates that microwave fixation using an on-line conveyor belt fixation process with an output of 4m3/hour using a microwave power supply of 230 kW costs approximately AU$ 16/m3 for electricity costs of AU$ 0.077/kW-h. When electricity cost are AUS$ 0.017/kW-h the treatment costs are reduced to AU$ 10/m3.
G Torgovnikov, P Vinden, E Mapanda, P R S Cobham
Microwave treatment to Accelerated fixation of copper-ethanolamine (Cu-EA) treated wood
2004 - IRG/WP 04-40271
This study evaluated the use of microwave post-treatment to accelerate fixation of copper-ethanolamine (Cu-EA) treated 19 mm southern yellow pine sapwood cubes. Cubes were pressure treated at 3.2 and 6.4 kg/m3 Cu retention target, after which they were microwave post treated during different duration periods. An accelerated AWPA leaching test was conducted during 300 hours to determine the amount of copper leached after the microwave treatment. The amount of copper leached was reduced 40 % after 5-min microwave treatment. The moisture content and the temperature of the cubes were monitored during the microwave treatment. This study clearly demonstrated that post-microwave treatment could be used effectively to reduce the amount of copper leached after 300 hours accelerated leaching test. Further work is needed to determine the effect of the sample size, the power and duration of the microwave treatment on copper leachability.
Jinzhen Cao, D P Kamdem