The protection of wood against biodeteriorating agents like termite during processing or in service has call for serious possible approach using new safer, environmental friendly preservatives hence ...this study therefore evaluated Azadirachta indica seed oil against termite attack on Gmelina arborea and Triplochiton scleroxylon wood. The seed oil was obtained using a soxhlet apparatus and N-hexane as the solvent. The wood was dimensioned into 20x20x20 mm and the seed oil was applied by brushing, dipping and soaking and exposed to termitarium while the absorption rate and weight loss to termite attack were determined. Data collected was analyzed using simple statistics and analysis of variance at α0.05. The antimicrobial properties of the need seed oil are due to the availability of phytochemicals which promote antimicrobial activity. The maximum wood protection against termite of all the methods of application was obtained from soaking. The absorption and weight loss ranged from 11.20 - 43.88 % and 56.50 -61.58 % for G. arborea and T. scleroxylon respectively. However, all the application methods used for the wood treatment proved to be effective over the untreated wood.
Keywords: phytochemicals, seed oil, wood species, wood preservation, wood termite
This review compiles various literature studies on the environmental impacts associated with the processes of thermal modification of wood. In wood preservation field, the wood modification by heat ...is considered as an ecofriendly process due to the absence of any additional chemicals. However, it is challenging to find proper scientific and industrial data that support this aspect. There are still very few complete studies on the life cycle assessment (LCA) and even less studies on the environmental impacts related to wood heat treatment processes whether on a laboratory or on an industrial scales. This comprehensive review on environmental impact assessment emphasizes environmental categories such as dwindling of natural resources, cumulative energy intake, gaseous, solid and liquid emissions occurred by the thermal-treated wood industry. All literature-based data were collected for every single step of the process of wood thermal modification like resources, treatment process, transport and distribution, uses and end of life of treated wood products.
The possibility of using coffee silverskin, an industrial waste from the coffee roasting process, as an antifungal feedstock in wood preservative formulations was investigated. Silverskin hot water ...extract and its antifungal properties in vitro against Rhodonia (Poria) placenta, Gloeophyllum trabeum, and Trametes versicolor were characterized, and its in vitro effects on wood decay caused by Coniophora puteana were analyzed. A kinetic luminescent bacteria test was performed using Aliivibrio fischeri to measure the acute ecotoxicity of the silverskin extracts. The antifungal test showed 60–70% growth inhibition of the studied fungi at higher concentrations—3%—but did not meet the high inhibition—100%—of the commercial wood preservative. The phenolic compounds, such as chlorogenic acid and its derivatives, and caffeine derivatives, were the main constituents of the silverskin extracts and considered the responsible compounds of the fungal inhibition. The silverskin extracts were significantly less toxic than the commercial copper-based wood preservative. Revalorization of silverskin from industrial residues does not perform as a wood preservative but it remains a potential source of antifungal chemicals for wood preservative formulations.
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•Extracts were assessed for antifungal activity, decay resistance and ecotoxicity.•Coffee silverskin extracts can inhibit decay fungi.•Silverskin extracts had lower acute ecotoxicity than the commercial preservative.•Coffee silverskin waste is a potential feedstock for antifungal chemicals recovery.
Impregnation with biocides is an efficient approach to prolong the service life of wood materials, but most biocides pose a toxic threat to human health and the environment. This study presents a ...novel and green system for protecting Masson pine and pond cypress against the brown-rot fungus Gloeophyllum trabeum through a combination of 4,5-dichloro-2-n-octyl-3-isothiazolinone (DCOI) and chelators with high iron affinity. As results, both diethyltriaminepentaacetic acid (DTPA) and tetrasodium iminodisuccinate (IDS) reduced the mass losses of Masson pine and pond cypress, but neither chelator inhibited the growth of G. trabeum at a low concentration. The compound system was more efficient in reducing the mass loss of Masson pine compared to DCOI alone. Moreover, the DCOI degradation rate decreased significantly by IDS, suggesting that chelators with high iron affinity can protect organic biocides from degradation. All data supported that the chelators were able to enhance the organic biocide in improving wood decay resistance, and the involved mechanism was mainly due to the restriction on iron-based Fenton chemistry deployed by brown-rot fungi. This study provides valuable insight into the development of environmentally benign techniques to preserve wood.
Chitosan (C) is a natural antimicrobial compound that has been widely explored for wood protection, but its application is limited by its high leachability. Genipin is a biobased crosslinking agent ...that can crosslink with chitosan under mild conditions. This study aims at examining the decay resistance and leachability of genipin-crosslinked chitosan (GC) treated wood against common wood-decaying fungi. GC formation was confirmed using Fourier transform infrared spectroscopy and Thermogravimetric analysis. The antifungal efficacy of GC against two brown-rot fungi, Gloeophyllum trabeum (G.t.) and Rhodonia placenta (R.p.) and two white-rot fungi, Trametes versicolor (T.v.) and Irpex lacteus (I.l.) was first determined using malt-gar as substrate, which revealed that GC exhibited similar efficacy as C treatments in inhibiting the growth of all fungi studied. Micrographs of light and fluorescence microscopy showed changes in fungi morphology and nuclei deformation due to the effect of GC. GC-treated wood samples show an increased retention and mass gain as the function of treating concentrations, which were as high as 21 kg/m2 and 3.6%, respectively. However, upon leaching test, the mass gain of 3% GC treated softwood and hardwood was reduced to 1.6% and 0.9%, respectively, indicating cross-linking chitosan with genipin did not reduce the leaching rate of chitosan. In terms of durability testing, GC treated wood samples showed significantly lower mass loss ranging from 11 to 15% than those of the control groups of ≥30% regardless of the leaching test.
•Chitosan can crosslink with genipin with improved thermal stability.•Genipin crosslinked chitosan has similar antifungal properties against common wood decaying fungi.•Genipin crosslinked chitosan treatment caused morphological changes and nuclei deformation of all the tested fungi.•Genipin crosslinked chitosan treated wood has limited improved leachability.
Fungi and microbes can remarkably degrade the appearance and durability of organic materials, such as wood. The inhibitory effects of natural phenolics may offer more sustainable alternatives to ...preserve wood than the toxic biocides that are currently used. Although pure caffeine has been proven to have antibacterial properties, the applicability of spent coffee in wood preservation has not been determined. This work conducted in vitro tests with three brown rot and one white rot fungi and demonstrated the potential of spent coffee-derived cinnamates, analyzed with high-performance liquid chromatography, as antimicrobial agents. Spent coffee at concentrations of 1% and above in the growing media caused significant growth suppression of all of the fungi. This was not only because of the caffeine, but also the other chemicals present in the residue extracts, which demonstrated that spent coffee could be used as a source of green chemicals in wood preservative formulations.
A simple, one-step and one-pot method was used to synthesize amphiphilic self-assembling chitosan-g-PMMA nanoparticles (∼100nm diameter by SEM, but ∼150–200nm in water by DLS), containing ∼25–28wt.% ...(∼82–93% capture efficiency) of the fungicide tebuconazole. The matrix composition was selected to be environmentally low impact, while the nanoparticle preparation conditions were designed to ensure the nanoparticles were sufficiently small to be able to penetrate the pit pairs of solid wood. These nanoparticles were delivered into southern pine sapwood blocks at target fungicide retentions of 0.2, 0.4 and 0.8kg tebuconazole/m3wood. SEM analysis of a 19mm×19mm×455mm nanoparticle-treated wooden stake confirmed penetration throughout the interior of the treated stake. Leaching studies confirmed that biocide introduced into sapwood via nanoparticle carriers leached only about 9% as much fungicide as solution-treated controls, while soil jar tests showed the nanoparticle-treated wood blocks effectively protected the wood from biological decay when tested against G. trabeum, a brown rot fungus.
A need exists to develop new organic, environmentally benign wood preservatives for industrial applications to replace the older creosote and pentachlorophenol systems. In this study the performance ...of creosote at three retentions was compared to a new wood preservative candidate formulated with Polymeric Xylenol Tetrasulfide (PXTS) in an E7 AWPA field study using two sets of southern pine and yellow poplar field stakes treated with three creosote retentions or five retentions of PXTS. The stakes were installed at two test sites and evaluated after 3,5 years, 6 years, and 14 years exposure. After six years of exposure at both sites, which is double the minimum recommended exposure period of three years’ field data for AWPA submission of a proposed new preservative system, the average decay ratings data for southern pine stakes after three years exposure was not sufficient to definitively determine which system provides superior protection against decay and termite attack (Creosote at the AWPA UC4B pole retentions versus pine stakes treated with much lower PXTS levels). However, after a longer exposure time of 14 years the data conclusively shows that pine stakes treated to the utility pole AWPA UC4B creosote retention performed poorer at both sites against decay and termite degradation than pine stakes treated with 26 Kg/m3 PXTS. Similar results were obtained with the yellow poplar stakes. We conclude that: 1) much longer E7 exposure times are necessary then the minimum recommended three years in the AWPA GDA Standard for submission of new systems to definitively determine the efficacy of a proposed oil borne system compared to the efficacy of a traditional organic preservative for commercial applications, and 2) long term field PXTS performance against decay and termite deterioration is equal or greater than that obtained with creosote at about four times the PXTS retention
In-depth knowledge of the interaction effects of wood and preservative chemicals on surface adhesion characteristics is crucial for developing pathways to improve the adhesive bonding of treated ...woods. Therefore, this study investigated fundamental changes in the surface adhesion-related chemical characteristics of E. grandis sapwood and heartwood impregnated with copper azole (CA) and disodium octaborate tetrahydrate (DOT) wood preservatives. The characterization techniques employed include scanning electron microscopy integrated with energy-dispersive X-ray spectroscopy and Fourier transformed infrared spectroscopy. The results obtained revealed that CA and DOT impregnations significantly altered the acidity and reduced the polar functional groups on E. grandis sapwood and heartwood surfaces. The effect was more pronounced with DOT impregnation and on the sapwood. The observed modifications signal that the CA- and DOT-treated wood adhesion could be inhibited due to reduced opportunity for chemical bonding between the treated wood and adhesive molecules. Furthermore, there is a high likelihood of the hindrance of adhesion via mechanical interlocking as a result of chemical deposits, particularly in copper azole-impregnated wood. Considering the observed changes in the surface chemical characteristics of the CA and DOT-impregnated E. grandis, adhesive compatibility and adapting bonding parameters, such as assembly time and bonding pressure could be vital in ensuring adequate bonding of the treated E. grandis wood.
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