Mode of action of brown rot decay resistance of thermally modified wood: resistance to Fenton’s reagent

Hosseinpourpia, Reza; Mai, Carsten

doi:10.1515/hf-2015-0141

Cited by 20 publications

(11 citation statements)

References 34 publications

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“…This is in accordance with Hosseinpourpia and Mai, who showed that diffusion of iron was inhibited in acetylated wood with a high WPG [102]. A similar experiment was performed on thermally modified wood, which showed a significant reduction in iron diffusion in this material but no threshold [91].…”

Section: Diffusion In Modified Woodsupporting

confidence: 89%

“…In vitro studies mimicking both the oxidative and the enzymatic brown rot degradation processes have shown that even though the wood modification provides some protection against degradation by Fenton derived OH radicals, the radicals were able to depolymerise wood polysaccharides in acetylated, DMDHEU-treated and thermally modified wood [89][90][91][92]. Furthermore, fungal cellulases were able to degrade the wood polysaccharides in acetylated and DMDHEU-treated materials but at a slower rate than in untreated wood [85,89].…”

Section: Fungal Response To Wood Modification and Inhibition Of Decaymentioning

confidence: 99%

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The Importance of Moisture for Brown Rot Degradation of Modified Wood: A Critical Discussion

Ringman

Beck

Pilgård

2019

Forests

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The effect of wood modification on wood-water interactions in modified wood is poorly understood, even though water is a critical factor in fungal wood degradation. A previous review suggested that decay resistance in modified wood is caused by a reduced wood moisture content (MC) that inhibits the diffusion of oxidative fungal metabolites. It has been reported that a MC below 23%–25% will protect wood from decay, which correlates with the weight percent gain (WPG) level seen to inhibit decay in modified wood for several different kinds of wood modifications. In this review, the focus is on the role of water in brown rot decay of chemically and thermally modified wood. The study synthesizes recent advances in the inhibition of decay and the effects of wood modification on the MC and moisture relationships in modified wood. We discuss three potential mechanisms for diffusion inhibition in modified wood: (i) nanopore blocking; (ii) capillary condensation in nanopores; and (iii) plasticization of hemicelluloses. The nanopore blocking theory works well with cell wall bulking and crosslinking modifications, but it seems less applicable to thermal modification, which may increase nanoporosity. Preventing the formation of capillary water in nanopores also explains cell wall bulking modification well. However, the possibility of increased nanoporosity in thermally modified wood and increased wood-water surface tension for 1.3-dimethylol-4.5-dihydroxyethyleneurea (DMDHEU) modification complicate the interpretation of this theory for these modifications. Inhibition of hemicellulose plasticization fits well with diffusion prevention in acetylated, DMDHEU and thermally modified wood, but plasticity in furfurylated wood may be increased. We also point out that the different mechanisms are not mutually exclusive, and it may be the case that they all play some role to varying degrees for each modification. Furthermore, we highlight recent work which shows that brown rot fungi will eventually degrade modified wood materials, even at high treatment levels. The herein reviewed literature suggests that the modification itself may initially be degraded, followed by an increase in wood cell wall MC to a level where chemical transport is possible.

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Section: Diffusion In Modified Woodsupporting

confidence: 89%

Section: Fungal Response To Wood Modification and Inhibition Of Decaymentioning

confidence: 99%

The Importance of Moisture for Brown Rot Degradation of Modified Wood: A Critical Discussion

Ringman

Beck

Pilgård

2019

Forests

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“…Hosseinpourpia & Mai (2016a, 2016c have conducted a series of experiments where modified wood veneers are exposed sequentially to solutions of iron ions and hydrogen peroxide, mimicking the oxidative Fenton chemistry of brown-rot fungi. Their results show that for acetylated and phenol-formaldehyde modified wood, hydrogen peroxide is not consumed in a solution with iron ions and modified wood after 48 hours of exposure given that the modification intensity (WPG) is high enough (Hosseinpourpia & Mai 2016a. Moreover, controls of modified wood of adequately high WPG exposed only to the iron ion solution did not take up iron during the 48 hour experiment.…”

Section: Iforest -Biogeosciences and Forestrymentioning

confidence: 99%

Moisture in modified wood and its relevance for fungal decay

Thybring¹,

Kymäläinen²,

Rautkari³

2018

iForest

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Water plays an essential role in fungal decay of wood, and limiting the cell wall moisture content by chemical modification can effectively improve the durability of the material. Investigating the wood-water relations of modified material under climatic conditions relevant for fungal decay are, however, experimentally challenging. Most studies in literature therefore focus on moisture sorption under conditions outside those of importance for fungal decay. This review discusses the validity of such data for characterising the wood-water relations at very humid climatic conditions, relevant for fungal decay. Moreover, the review attempts to cover the basics of fungal decay, the important role of water, and how controlling water content by modification can improve durability.

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“…The process is traditionally characterised by low heating rates (<50 °C.min -1 ) and by a relatively long reactor residence time (typically higher than 30 minutes) [3]. The resulting product is intermediate between wood and charcoal and exhibits several advantages when compared to the original material such as an increased energy density [4], a decreased hygroscopicity, a dimensional stabilization [4], an increased resistance to biological decay [5], a loss of mechanical resilience [6], etc. Several studies have shown the efficiency of heat treatment on easing biomass grinding.…”

Section: Introductionmentioning

confidence: 99%

Effect of torrefaction intensity on the flow properties of lignocellulosic biomass powders

Pachón‐Morales

Colin

Pierre

et al. 2019

Biomass and Bioenergy

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Flowability characterization of milled lignocellulosic biomass is essential for developing viable conveying, storing and handling solutions for gasification processes. This study investigated the effect of torrefaction on particles size and shape obtained after grinding and on flow properties of pulverized wood.Spruce and poplar samples with six torrefaction intensities were knife-milled to obtain biomass powders.Particles size and shape distribution were assessed using a morphological particle size analyser and flowability parameters were determined with a ring shear tester. A more intense treatment produces finer, rounder and more regular particles. Simultaneously, a gradual shifting was observed from a cohesive behaviour for native biomass to a nearly free flowing behaviour for the most intensively treated samples. The trends in flowability cannot be explained by the size reduction nor the increase of distribution width. Instead, the explanation lies in the reduction of shape factor and the sharpness of particle surfaces for treated samples. However, all observations are consistent with the loss of resilience of treated wood. From our results, it is clear that torrefaction, in addition to its interest on reduction of energy consumption of grinding, should also be considered as a pre-treatment step allowing to modify the flow behaviour of biomass powders.

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Mode of action of brown rot decay resistance of thermally modified wood: resistance to Fenton’s reagent

Cited by 20 publications

References 34 publications

The Importance of Moisture for Brown Rot Degradation of Modified Wood: A Critical Discussion

The Importance of Moisture for Brown Rot Degradation of Modified Wood: A Critical Discussion

Moisture in modified wood and its relevance for fungal decay

Effect of torrefaction intensity on the flow properties of lignocellulosic biomass powders

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