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Fungal degradation of wood treated with metal-based preservatives. Part 2: Redox states of chromium
1996 - IRG/WP 96-10164
Concerns have arisen about the leaching of heavy metals from wood treated with metal-based preservatives, such as chromated copper arsenate (CCA). Of particular concern is the toxic redox state of chromium and arsenic in aging and decayed CCA-treated wood. Generally, hexavalent chromium is more toxic than trivalent chromium and trivalent arsenic is more toxic than pentavalent arsenic. The desired outcome from treating wood with CCA is total change of Cr(VI) to Cr(III) and As(III) to As(V). As part of an on-going study to determine the fate of copper, chromium and arsenic during aging and decay of CCA-treated wood, we detected Cr(III) and Cr(VI) in situ in CCA-treated southern yellow pine lumber. The redox states of Cr were determined using synchrotron X-ray fluorescence spectroscopy (SXRF). An SXRF microprobe was used to to detect Cr redox states by measuring X-ray absorption near-edge structure (XANES). The ratio of Cr(III) to Cr(VI) was determined (1) on the surface and interior of lumber two years after CCA treatment and (2) in lumber during decay by a CCA-tolerant fungus, Meruliporia incrassata TFFH-294. The XANES spectrum for Cr(VI) has a strong pre-edge feature that is not present in the spectrum for Cr(III). Only the Cr(III) XANES spectrum was detected on the surface and in the interior of the wood, indicating total reduction of Cr(VI). The XANES spectrum for Cr(III) was detected in wood after 12 week decay by Meruliporia incrassata TFFH-294, indicating that the fungus does not oxidize Cr(III) to Cr(VI) during the decay process. We are currently using XANES spectroscopy to detect and map in situ redox states of As in CCA-treated wood.
B Illman, S Bajt, T L Highley

A study of salt imbalances observed in recycled copper/chrome/arsenic preservative solutions in commercial practice
1987 - IRG/WP 3461
The study reported monitored tank solutions, sludge and other by-products using a standard CCA solution, when recycled. This recycling of the CCA solution is quite usual in between any commercial treatment schedules. Salt imbalances were observed and the possible reasons for such phenomena were studied. The paper discusses the procedure followed, the method of sampling the liquid after the charge and the analysis, to arrive finally at an aggregation and conclusion from the data.
V R Sonti, S Sonti, B Chatterjee

The variability of preservative distribution in test blocks
1973 - IRG/WP 220
The techniques for the assessment of likely effectiveness of preservative systems have long been the subject of much discussion. The whole field has recently been reviewed by Hilditch and Hamblyn (1971) who described in detail many of the laboratory test procedures used, but who also indicated the deficiencies in many of these techniques. It has long been the view of many associated with the wood preservation industry that laboratory tests can only serve as a preliminary method of screening and that final approval by both the company marketing the development and independent authorities, on whom the burden of approval rests, can only be given after detailed testing in the field. The aim of the simple piece of work described in this paper, is to lok at the variability which one might expect in the distribution of preservative in test blocks destined for laboratory fungal evaluation.
F W Brooks, M R Gayles, R W Watson

Photo-discoloration and Degradation of Wood and its Stabilisation by Modification with Benzoyl Chloride
2004 - IRG/WP 04-40274
Photo degradation of Pinus roxburghii (chir pine) and Hevea brasiliensis (rubber wood) was studied under artificial accelerated weathering conditions in a Xenon test chamber. The irradiated samples were analyzed for color changes and chemical changes. Analysis of colour changes in wood surfaces by UV-Vis. irradiation was carried out using a colour measuring (CIELAB) system and chemical changes were monitored using FTIR and fluorescence spectroscopy. Irradiation modified physical and chemical characteristics of wood surfaces and resulted in rapid colour changes, reduction in lignin content and increased concentration of chromophoric groups on the wood surfaces. Colour changes were correlated with formation of carbonyl groups and lignin decay rate determined by FTIR measurements. Fluorescence emission spectra measured from un-weathered wood shows excitation wavelength dependence. Photo irradiation leads to a rapid reduction in the emission intensity, broadening of spectra and a significant red shift in the emission maximum. Photo stability of wood surfaces esterified with benzoyl chloride was also assessed. The modification was characterized and analyzed by fluorescence and FTIR spectroscopy and photo-stability of modified wood was assessed. Esterification of wood by benzoyl chloride suppressed the colour changes (photo-discoloration) and also reduced the lignin degradation and generation of carbonyl groups on irradiated wood surfaces. Results show esterification of wood with benzoyl chloride was effective at inhibiting photo-degradation of wood polymers.
K K Pandey

Correlation between changes in colour and chemical composition during photo-degradation of wood surfaces
2005 - IRG/WP 05-40301
Changes in colour of wood (yellowing) during photo degradation or weathering reflect chemical changes in wood. Therefore, the relationship between changes in chemical composition and CIELAB colour parameters is very important to characterize photodegradation of lignocellulosic surfaces. In this study, the changes in chemical composition and yellowing due to photo-degradation was studied by exposing wood surfaces of Pinus roxburghii (chir pine) to a xenon source. Changes in chemical composition were monitored by measuring IR and fluorescence spectra and were correlated with colour changes. A linear correlation between degradation of lignin and total colour change (E) was observed.
K K Pandey

Laboratory evaluation of chlorothalonil against the Formosan subterannean termite
1992 - IRG/WP 92-1559
The fungicide chlorothalonil was evaluated as a wood preservative to prevent attack by the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). Southern yellow pine wafers treated with chlorothalonil (CTL) in P9 oil, CTL + chlorpyrifos in P9 oil, or CTL in xylene were conditioned by evaporative aging at 40° C for 4 weeks and exposed to termite attack in a modified ASTM D3345 4-week laboratory test. Actual CTL retentions were assayed post-test by X-ray fluorescence, and an approximate 50% decrease in CTL concentration found from the pretest nominal CTL retentions. With all three treatments, termite feeding on wood with actual retentions of 0.05-0.10 pcf (corresponding to 0.10-0.21 pcf nominal) did not differ significantly from the respective solvent controls. CTL retentions of 0.13-0.15 pcf (0.41-0.45 pcf nominal) limited wood weight loss from termite feeding to 6-13%, and retentions of 0.26-0.39 pcf (0.81-0.94 pcf nominal) CTL resulted in only 3-4% wood weight loss. Termite mortality was correlated with CTL retention. These results demonstrate that chlorothalonil is toxic to termites, and at the appropriate retention will deter Coptotermes formosanus from feeding on treated wood.
J K Grace, P E Laks, R T Yamamoto

Application of energy dispersive X-ray fluorescence spectrometry to the quantitative analysis of organotin preservative solutions and treated wood
1978 - IRG/WP 3125
One technique frequently used for the quantitative analysis of material containing inorganic compounds is energy dispersive X-ray fluorescence spectrometry. It has been shown previously that this technique can be readily used to determine the retentions of chromated copper arsenate and ammoniacal copper arsenate treated wood. This paper reports the results of a preliminary study to determine whether energy dispersive spectrometry may be used to assay both organotin treated wood and also the preservative in solution. Five objectives were established for the study and they were (i) Assessment of the instrumental error; (ii) Determination of the error due to sample preparation; (iii) Selection of a suitable live data accumulation time; (iv) Preparation of a calibration graph using tributyltin acetate; and (v) To initate studies on interelement interference effects.
J N R Ruddick

Basidiospore structure and germination of Serpula lacrymans and Coniophora puteana
1988 - IRG/WP 1340
Using a nuclear staining technique and fluorescence microscopy, the basidiospores of Serpula lacrymans were shown to be uninucleate whereas those of Coniophora puteana were binucleate. The germination rate of the Serpula lacrymans spores, which was considerably lower than that of Coniophora puteana, decreased further after storage or heat treatment. Transmission electron micrographs indicate that the majority of Serpula lacrymans spores have a disorganised internal cellular structure and are filled mainly with lipidic material; these spores lack a nucleus. Germination of viable Serpula lacrymans spores occurs through the spore apiculus or through the spore apex. In contrast, Coniophora puteana spores can produce two germ tubes and germinate simultaneously through the apiculus and the apex.
B M Hegarty, U Schmitt

A comparison of analytical techniques
1995 - IRG/WP 95-20061
This paper compares carefully-controlled weight retentions and analysis by XRF, ICP, combustion methods and a new extraction procedure for the new preservative, Copper(II) Dimethyldithiocarbamate (CDDC). Various experimental parameters such as particle size and drying conditions were investigated. In general, the correlations between and among the procedures are very high. The extraction-colorimetric procedure developed for assay of CDDC was verified by comparison to AWPA Standard analytical techniques.
A C Gallacher, C R McIntyre, M H Freeman, D K Stokes, W B Smith

The use of low cost X-ray fluorescence instruments in the determination of copper chromium and arsenic in preservative treated wood
1987 - IRG/WP 2278
Internal quality control in timber treatment plants can be pursued by analysis of preservative treatment solutions and treated timber. Treaters must proceed with costly and lengthy analyses through analytical laboratories. An alternative approach for the timber treater, is to use low cost analysers (L.C.A.'s) based upon x-ray fluorescence. Detailed comparisons have been made between standard methods (Atomic Absorption Spectrophotometry) and L.C.A.'s for the analysis of CCA treated timber. Results indicated that no difference was found between different formulations. One L.C.A. tested provided more consistent results than those generated by standard methods. Average results provided by the L.C.A.'s were both higher and lower than standard methods. This finding may be related to the retention of preservative being tested. The results indicate that L.C.A.'s promise to be extremely useful to the timber treatment industry.
J Norton, L E Leightley

Evaluation of rapid methods for detecting wood preservatives in waste wood
1994 - IRG/WP 94-50024
For the disposal of wood waste under ecological sound conditions information about its hazardous potential is required. Several analytical methods are available for the detection of most elements in wood preservatives. Industrial process conditions, however, demand methods with very short turn around times. In this research several methods of analysis were judged on their speed and accuracy. A number of inorganic wood preservatives and organic preservatives containing detectable elements were studied (i.e. CCA, CCB, ZKF, CC, PCP [Cl]). Both solutions and treated wood samples were analyzed with energy dispersive X-ray fluorescence (EDXRF), laser-ablation ICP and coulometry. The coulometrical methods provided very precise analyses of solid wood in a turn around time of approximately 10 minutes. With laser-ablation ICP the results were unreliable. This is caused by the solid sample preparation procedure. EDXRF can provide reliable analyses in approximately 30 seconds. This method is not suitable, however, at low levels of concentration (< 50 ppm).
W J Homan, H Militz

Assaying Pentachlorophenol-treated Wood Using XRF
2007 - IRG/WP 07-20362
A study was conducted to evaluate the effect of oil type on the performance of test posts treated with oil-penta and exposed in DeQueen, AR for forty years in ground contact. The original assays for the poles were done by lime ignition, a practice used sparingly today in treating plants or by independent inspectors, in part due to the complicated analysis procedure and chances for error. XRF instruments for chlorine analysis have become commonplace. The question put forward by many inspectors, agencies, and treaters is ‘Will XRF accurately predict lime ignition results?’. This study encompassed seven different oil systems. Regression analysis yielded an R2 value over 97% when using XRF to predict lime ignition values. The only caveat was that a proper calibration standard was required for the XRF analysis. Users should be confident that properly derived XRF values will match lime ignition values within 5%.
H M Barnes, C R McIntyre, D W Bullock , M H Freeman, G B Lindsey

Use of X-Ray Fluorescence (XRF) Spectroscopy to Determine 4,5-Dichloro-2-n-Octyl-4-Isothiazolin-3-one (DCOIT) in Wood
2007 - IRG/WP 07-20373
Organic preservative based systems are being developed as replacements for the metal based systems. Typically the chemical actives of organic preservative systems are analyzed using HPLC or GC. However, these analytical techniques require complex sample processing and involve relatively long analysis times. In addition the equipment requires maintenance and a skilled operator. One organic preservative that is currently being developed for a range of uses in wood preservation, 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT), contains both sulfur and chlorine functionality, providing the potential for the use of XRF for its analysis in both treating solutions and in wood. In this study the applicability of XRF to determine the concentration of DCOIT using the chlorine and sulfur x-ray emissions was determined.
P Walcheski, J Ashmore, D M Laganella

Wood biodeterioration monitoring using molecular fluorescence
2016 - IRG/WP 16-20589
Wood is an extremely complex and heterogeneous biological material, susceptible to biodeterioration by wood-destroying organisms. This process can be evaluated by natural resistance tests or non-destructive techniques, such as molecular fluorescence. The fluorescence of wood can be attributed to the presence of fluorophores groups or extractives, as a characteristic of some species. This study aimed to assess emitted fluorescence by Simarouba amara and Eucalyptus saligna woods after Trametes versicolor and Gloeophyllum trabeum decay fungi. The results showed that the molecular fluorescence was efficient to detect and discriminate previously the decay fungi in both wood species.
E Meneses Oliveira, A Florian da Costa, J W Batista Brag

Preparation of Calibration Standards for the Analysis of Pentachlorophenol in Treated Wood by X-ray Fluorescence
2016 - IRG/WP 16-20591
The primary purpose of this project was to develop a method for preparing calibration standards that can be used by the wood treating industry to calibrate X-ray fluorescence instrumentation. Calibration standards of penta/P9-oil in southern yellow pine that cover the retention range of 0.2 to 0.9 pcf (0.6 to 1.9 %) were successfully prepared. A detailed procedure for mixing penta in treating solution with ground southern pine is described. Users can choose to reference the penta concentration in the standards based on lime ignition analysis of the treating solution or lime ignition analysis of each standard. XRF measurements of penta concentrations are 5-8% higher than the values of penta in wood measured by the lime ignition or the values of penta in wood calculated on the bases of lime ignition measured penta concentration in treating solution. Standards stored at ambient temperature were stable over a period of 1 to 1.5 years during the time of this study. This study focused on preparation of standards and does not include the effects of boring collection, storage, drying, and grinding on analytical error.
L L Ingram Jr, H M Barnes, R Shmulsky, D Jeremic

Measurement of copper concentration in Cu-HDO treating solutions by handheld XRF
2022 - IRG/WP 22-20685
Copper based preservatives diluted in water dominate the wood preservative industry around the world. Periodically measurements and adjustments of the concentration of treating solutions must be performed as a part of the quality control at the treatment plant to achieve desired quality of the preservative treated wood. Many analytical methods are time consuming and must be performed under laboratory conditions, while others that are rapid and easy to apply at industry sites can be sensitive to impact from impurities, etc. The aim of this study was to evaluate handheld X-ray fluorescence (XRF) spectrometry as a tool for measuring copper concentration in CuHDO treating solutions. The material used in the study comprised samples of Wolmanit CX-8 (CuHDO) diluted in distilled water and samples from Wolmanit CX-8 treating solutions from Norwegian impregnation plants. All the preservative solution samples were analysed with a handheld Niton XL5 Plus XRF Analyzer. Atomic absorption spectrophotometry (AAS) was used as a reference method. The major advantages of portable handheld XRF spectrometry include: on-site immediate availability of analytical results, non-destructive analysis, a multielement capability, speed of operation and access to valuable/unique samples that otherwise would be unavailable or had to be transported to a laboratory for chemical analysis. The results from this study show that there is a good linear correlation with the XRF data and the corresponding laboratory results and that it is possible to use data measured with a handheld energy dispersive XRF-analyser for accurate calibrations and predictions of the copper concentration of treating solutions of Wolmanit CX-8.
P O Flaete