This page has only limited features, please log in for full access.

Dr. Ahmed Koubaa
Université du Québec en Abitbi-Témiscamingue

Basic Info


Research Keywords & Expertise

0 Surface Chemistry
0 surface characterization
0 Wood Biomass
0 Composites And Applications
0 Wood Technology

Fingerprints

Surface Chemistry

Honors and Awards

The user has no records in this section


Career Timeline

The user has no records in this section.


Short Biography

The user biography is not available.
Following
Followers
Co Authors
The list of users this user is following is empty.
Following: 0 users

Feed

Journal article
Published: 17 August 2021 in Industrial Crops and Products
Reads 0
Downloads 0

The project aims to develop cellulose in new biocomposites to produce dielectric materials based on thermoplastic matrices. Cellulose fibers bring multiple advantages to thermoplastic matrices in mechanical, physicochemical, thermal, and dielectric properties. Although these biocomposites are known for their advanced mechanical properties, only a few studies investigated their dielectric behavior and the effect of cellulose fibers on these properties. The bio-based composites must have better dielectric properties and excellent ductility to use as insulators in electrical cables. Thus, we investigated the dielectric properties (dielectric constant (ε’), loss factor (ε’’), conductivity (σ) and resistivity (ρ)) of high-density polyethylene (HDPE) and cellulose fibers composites. Results prove that the addition of cellulosic fibers increased the dielectric constant, the loss factor, and the conductivity of the materials compared to the neat polymer. Composites with 50 wt% fiber content showed the highest values. Therefore, the volume resistivity of all the composites studied decreased with frequency and fiber content. In addition, the reinforced polymer exhibited an intermediate thermal behavior between the polymer and the fibers. Thus, they are thermally stable materials up to 320 °C.

ACS Style

Asma Khouaja; Ahmed Koubaa; Hachmi Ben Daly. Dielectric properties and thermal stability of cellulose high-density polyethylene bio-based composites. Industrial Crops and Products 2021, 171, 113928 .

AMA Style

Asma Khouaja, Ahmed Koubaa, Hachmi Ben Daly. Dielectric properties and thermal stability of cellulose high-density polyethylene bio-based composites. Industrial Crops and Products. 2021; 171 ():113928.

Chicago/Turabian Style

Asma Khouaja; Ahmed Koubaa; Hachmi Ben Daly. 2021. "Dielectric properties and thermal stability of cellulose high-density polyethylene bio-based composites." Industrial Crops and Products 171, no. : 113928.

Journal article
Published: 15 July 2021 in Coatings
Reads 0
Downloads 0

The moisture sensitivity of wood–polymer composites (WPCs) is mainly related to their hydrophilic wood components. Coatings are among the alternatives that improve the dimensional stability of these composites. However, the adhesion of most coatings to the WPC surface is generally poor. Thus, chemical and/or mechanical treatments should be applied to the WPC surface to improve the coating adhesion. Therefore, the main objective of this study was to improve the adhesion coating of polypropylene (PP) WPCs through a chromic treatment. PP was reinforced by three different pulp fibers (kraft, thermomechanical (TMP), and chemothermomechanical (CTMP)) at three fiber contents (50, 60, and 70% w/w). A chromic treatment was applied to the PP-based WPCs to activate the surface of the composites and alter their roughness parameters, creating a higher interfacial zone that improved the bonding of the epoxy coating to the surface of the PP composites. The chromic treatment increased the roughness of the surface. An increase in profile and surface parameters was observed after treatment. This treatment modified the chemical composition of the surface by creating polar carbon–oxygen groups and increasing the carbonyl and hydroxyl indexes.

ACS Style

Marouan Rejeb; Ahmed Koubaa; Fayez Elleuch; François Godard; Sébastien Migneault; Besma Bouslimi; Mohamed Khlif; Hatem Mrad. Effects of Chromic Treatment on the Surface Properties of Polypropylene (PP) Wood Composites. Coatings 2021, 11, 851 .

AMA Style

Marouan Rejeb, Ahmed Koubaa, Fayez Elleuch, François Godard, Sébastien Migneault, Besma Bouslimi, Mohamed Khlif, Hatem Mrad. Effects of Chromic Treatment on the Surface Properties of Polypropylene (PP) Wood Composites. Coatings. 2021; 11 (7):851.

Chicago/Turabian Style

Marouan Rejeb; Ahmed Koubaa; Fayez Elleuch; François Godard; Sébastien Migneault; Besma Bouslimi; Mohamed Khlif; Hatem Mrad. 2021. "Effects of Chromic Treatment on the Surface Properties of Polypropylene (PP) Wood Composites." Coatings 11, no. 7: 851.

Journal article
Published: 07 July 2021 in Polymers
Reads 0
Downloads 0

Demand for high-performance biocomposites is increasing due to their ease of processing, low environmental impact, and in-service performance. This study investigated the effect of boric acid modification of wood flour on polycarbonate (PC) wood composites’ thermal stability, fire retardancy, water absorption, and creep behavior. The composites’ fire retardancy increased with increasing wood flour content, and their char residue increased by 102.3% compared to that of pure PC. However, the water absorption of the resulting composites increased due to the hydroxyl groups of the wood flour. Wood flour also improved the composites’ anti-creep properties. The excellent fire retardancy and anti-creep properties of wood–PC composites expand their use in the construction sector.

ACS Style

Jingfa Zhang; Ahmed Koubaa; Dan Xing; François Godard; Peng Li; Yubo Tao; Xiang-Ming Wang; Haigang Wang. Fire Retardancy, Water Absorption, and Viscoelasticity of Borated Wood—Polycarbonate Biocomposites. Polymers 2021, 13, 2234 .

AMA Style

Jingfa Zhang, Ahmed Koubaa, Dan Xing, François Godard, Peng Li, Yubo Tao, Xiang-Ming Wang, Haigang Wang. Fire Retardancy, Water Absorption, and Viscoelasticity of Borated Wood—Polycarbonate Biocomposites. Polymers. 2021; 13 (14):2234.

Chicago/Turabian Style

Jingfa Zhang; Ahmed Koubaa; Dan Xing; François Godard; Peng Li; Yubo Tao; Xiang-Ming Wang; Haigang Wang. 2021. "Fire Retardancy, Water Absorption, and Viscoelasticity of Borated Wood—Polycarbonate Biocomposites." Polymers 13, no. 14: 2234.

Journal article
Published: 13 June 2021 in Coatings
Reads 0
Downloads 0

Wood polymer composites (WPC) are sensitive to moisture because of the hydrophilic nature of the wood fibers. The main objective of this study was to improve the dimensional stability of WPCs by coating. Polypropylene and polylactic acid were reinforced by three pulp fibers (kraft, thermomechanical (TMP), and chemothermomechanical (CTMP)) at three fiber contents (50, 60, and 70% w/w). The resulting WPCs were coated using two commercial coatings, epoxy and acrylic. Kraft fiber WPCs were less sensitive to moisture than TMP and CTMP WPCs. These differences were explained by the crystallinity of the kraft fibers and their better interfacial adhesion to the polymers. The epoxy coating proved to be more effective than the acrylic coating and significantly reduced the water absorption and the thickness swell for all formulations. Negative relationships between the contact angle and water absorption were obtained. These relationships depend on the fiber content and type, the matrix nature, and the coating.

ACS Style

Marouan Rejeb; Ahmed Koubaa; Fayez Elleuch; François Godard; Sébastien Migneault; Mohamed Khlif; Hatem Mrad. Effects of Coating on the Dimensional Stability of Wood-Polymer Composites. Coatings 2021, 11, 711 .

AMA Style

Marouan Rejeb, Ahmed Koubaa, Fayez Elleuch, François Godard, Sébastien Migneault, Mohamed Khlif, Hatem Mrad. Effects of Coating on the Dimensional Stability of Wood-Polymer Composites. Coatings. 2021; 11 (6):711.

Chicago/Turabian Style

Marouan Rejeb; Ahmed Koubaa; Fayez Elleuch; François Godard; Sébastien Migneault; Mohamed Khlif; Hatem Mrad. 2021. "Effects of Coating on the Dimensional Stability of Wood-Polymer Composites." Coatings 11, no. 6: 711.

Journal article
Published: 24 May 2021 in Journal of Composites Science
Reads 0
Downloads 0

The characterization of the dielectric properties of wood–polymer composites (WPCs) is essential to understand their interaction with electromagnetic fields and evaluate their potential use for new applications. Thus, dielectric spectroscopy monitored the evolution of the dielectric properties of WPCs over a wide frequency range of 1 MHz to 1 GHz. WPCs were prepared using mixtures of different proportions (40%, 50%, and 60%) of wood and bark fibers from various species, high-density polyethylene, and maleated polyethylene (3%) by a two-step process, extrusion and compression molding. Results indicated that wood fibers modify the resistivity of polyethylene at low frequencies but have no effect at microwave frequencies. Increasing the fiber content increases the composites’ dielectric properties. The fibers’ cellulose content explains the variation in the dielectric properties of composites reinforced with fibers from different wood species. Indeed, composites with high cellulose content show higher dielectric constants.

ACS Style

Imen Elloumi; Ahmed Koubaa; Wassim Kharrat; Chedly Bradai; Ahmed Elloumi. Dielectric Properties of Wood-Polymer Composites: Effects of Frequency, Fiber Nature, Proportion, and Chemical Composition. Journal of Composites Science 2021, 5, 141 .

AMA Style

Imen Elloumi, Ahmed Koubaa, Wassim Kharrat, Chedly Bradai, Ahmed Elloumi. Dielectric Properties of Wood-Polymer Composites: Effects of Frequency, Fiber Nature, Proportion, and Chemical Composition. Journal of Composites Science. 2021; 5 (6):141.

Chicago/Turabian Style

Imen Elloumi; Ahmed Koubaa; Wassim Kharrat; Chedly Bradai; Ahmed Elloumi. 2021. "Dielectric Properties of Wood-Polymer Composites: Effects of Frequency, Fiber Nature, Proportion, and Chemical Composition." Journal of Composites Science 5, no. 6: 141.

Journal article
Published: 21 May 2021 in Industrial Crops and Products
Reads 0
Downloads 0

Fire risk limits further commercial utilization of bio-based composites. In this study, polycarbonate (PC) hybridization improved the fire retardancy and the mechanical properties of wood flour/high-density polyethylene (HDPE) bio-based composites. A boric acid treatment improved the thermal stability of wood flour; the latter was then combined with the PC and the HDPE to produce hybrid-polymer-based composites. This study characterized the chemical structure, microstructure, and properties of the resulting bio-based composites. Results showed that the PC dispersed in the polyethylene matrix as micro or nanoparticles. The addition of PC increased the thermal stability of the resulting composites, and the char residue rate increased by 6.7 % at a PC content of 28 %. PC particles acted as a nucleating agent for the crystallization behavior of the bio-based composites. Adding PC reduced the heat release rate of the composites upon combustion. The tensile strength and modulus of elasticity of the resulting composites increased by 27.7 % and 91.1 %, respectively. Meanwhile, flexural strength and elasticity increased by 22.7 % and 53.8 %, respectively. The creep strain of the composites gradually decreased with increasing PC content, indicating that the addition of PC increased the anti-creep properties of the composites. Thus, the plastic hybridization and the wood flour fire retardant treatment led to bio-based composites with improved strength, thermal stability, and inflammability by wood flour modification.

ACS Style

Jingfa Zhang; Ahmed Koubaa; Dan Xing; Haigang Wang; Fengqiang Wang; Xiang-Ming Wang; Qingwen Wang. Flammability, thermal stability, and mechanical properties of wood flour/polycarbonate/polyethylene bio-based composites. Industrial Crops and Products 2021, 169, 113638 .

AMA Style

Jingfa Zhang, Ahmed Koubaa, Dan Xing, Haigang Wang, Fengqiang Wang, Xiang-Ming Wang, Qingwen Wang. Flammability, thermal stability, and mechanical properties of wood flour/polycarbonate/polyethylene bio-based composites. Industrial Crops and Products. 2021; 169 ():113638.

Chicago/Turabian Style

Jingfa Zhang; Ahmed Koubaa; Dan Xing; Haigang Wang; Fengqiang Wang; Xiang-Ming Wang; Qingwen Wang. 2021. "Flammability, thermal stability, and mechanical properties of wood flour/polycarbonate/polyethylene bio-based composites." Industrial Crops and Products 169, no. : 113638.

Journal article
Published: 08 April 2021 in Agronomy
Reads 0
Downloads 0

This study evaluated the effects of de-inking paper sludge (DPS) and sewage sludge (SS) application on soil properties, and durum wheat growth and yield. A pot experiment was performed on Calcaric cambisol (clCM) and Cromic Luvisol (coLV) soils. Three DPS rates (0, 30, and 60 Mg ha−1) were studied with and without nitrogen fertilizer (280 kg NH4NO3 ha−1). DPS was also mixed with SS at two rates (5 and 10 Mg ha−1) to highlight the benefits of organic nitrogen compared to mineral nitrogen. DPS improved total organic carbon and nitrogen, mineral nitrogen, and soils cation exchange capacity, the 30% rate provided the greatest improvement in both soils. DPS increased grain and root P, K, Ca, and Mg contents in both soils. It also increased wheat straw N, P, Mg, and Ca for the same soil compared to the control. Mixed DPS treatments with nitrogen fertilizer enhanced grain yield by up to 38% and increased root biomass in the studied soils. Thus, DPS is a potential source of organic matter and a liming agent for acid soils when appropriate supplemental fertilizer is provided.

ACS Style

Emna Marouani; Besma Zarai; Khaoula Boudabbous; Naïma Kolsi Benzina; Noura Ziadi; Rahma Zoghlami; Besma Bouslimi; Ahmed Koubaa. Short-Term Effects of Biosolid Application on Two Mediterranean Agricultural Soils and Durum Wheat Yield. Agronomy 2021, 11, 709 .

AMA Style

Emna Marouani, Besma Zarai, Khaoula Boudabbous, Naïma Kolsi Benzina, Noura Ziadi, Rahma Zoghlami, Besma Bouslimi, Ahmed Koubaa. Short-Term Effects of Biosolid Application on Two Mediterranean Agricultural Soils and Durum Wheat Yield. Agronomy. 2021; 11 (4):709.

Chicago/Turabian Style

Emna Marouani; Besma Zarai; Khaoula Boudabbous; Naïma Kolsi Benzina; Noura Ziadi; Rahma Zoghlami; Besma Bouslimi; Ahmed Koubaa. 2021. "Short-Term Effects of Biosolid Application on Two Mediterranean Agricultural Soils and Durum Wheat Yield." Agronomy 11, no. 4: 709.

Journal article
Published: 01 January 2021 in Matéria (Rio de Janeiro)
Reads 0
Downloads 0
ACS Style

Alan Fernando Ney Boss; Helena Ravaglia Ferreira; Flavia Lega Braghiroli; Gisele Aparecida Amaral-Labat; Ariane Aparecida Teixeira de Souza; Hassine Bouafif; Ahmed Koubaa; Mauricio Ribeiro Baldan; Guilherme Frederico Bernardo Lenz e Silva. Investigation of sustainable porous carbon as radar absorbing material. Matéria (Rio de Janeiro) 2021, 26, 1 .

AMA Style

Alan Fernando Ney Boss, Helena Ravaglia Ferreira, Flavia Lega Braghiroli, Gisele Aparecida Amaral-Labat, Ariane Aparecida Teixeira de Souza, Hassine Bouafif, Ahmed Koubaa, Mauricio Ribeiro Baldan, Guilherme Frederico Bernardo Lenz e Silva. Investigation of sustainable porous carbon as radar absorbing material. Matéria (Rio de Janeiro). 2021; 26 (2):1.

Chicago/Turabian Style

Alan Fernando Ney Boss; Helena Ravaglia Ferreira; Flavia Lega Braghiroli; Gisele Aparecida Amaral-Labat; Ariane Aparecida Teixeira de Souza; Hassine Bouafif; Ahmed Koubaa; Mauricio Ribeiro Baldan; Guilherme Frederico Bernardo Lenz e Silva. 2021. "Investigation of sustainable porous carbon as radar absorbing material." Matéria (Rio de Janeiro) 26, no. 2: 1.

Original paper
Published: 13 October 2020 in Waste and Biomass Valorization
Reads 0
Downloads 0

Alkaline organic residues, such as wood ash (WA), deinking paper sludge (DPS), and mixed paper sludge (MPS) could have a significant potential for mitigating greenhouse gases (GHG) when they are used for land application. The DPS was mixed and then granulated with MPS, WA and/or composted DPS to form pellets. A 56-d incubation study was carried out to investigate the effect of alkaline organic residue pellets on: (1) the biological and chemical properties of acidic clayey soil; (2) on carbon dioxide (CO2), on methane (CH4), and nitrous oxide (N2O) soil emissions. The experimental design included eight different treatments: unfertilized control (Control), fertilized control with mineral nitrogen (controlF), and six pelleted alkaline organic residue amendments (T1–T6) combined with mineral nitrogen fertilizer. The six amendments were: (T1) 100% DPS; (T2) 100% composted [50% poultry manure and 50% T1]; (T3) 50%WA + 50% T1; (T4) 50% WA + 50% T2; (T5) 50%T2 + 30%WA + 20% MPS; (T6) 50% T1 + 30%WA + 20% MPS. The results showed that alkaline residues significantly increased soil pH, the concentration of water-extractable organic carbon, and water-extractable nitrogen. Alkaline treatments had a positive effect on soil microbial activity. The highest mitigation efficiency of cumulative CO2 was obtained with T4, which released 10% less CO2 than other treatments. No significant effect on cumulative CH4 emissions was observed. Total cumulative N2O emissions were reduced by 37% with T5. Our study also showed that organic pellets based on alkaline residues improved the soil properties and can play a role in the mitigation of GHG in acidic clayey soil. Therefore, the co-application of alkaline organic residue pellets with chemical fertilizer might be considered as a sustainable approach in agriculture.

ACS Style

Emna Marouani; Noura Ziadi; Vicky Lévesque; Naïma Kolsi Benzina; Besma Bouslimi; Ahmed Koubaa. Mitigation of CO2, CH4 and N2O from Acidic Clayey Soil Amended with Fertilizer Pellets Based on Alkaline Organic Residues. Waste and Biomass Valorization 2020, 12, 3813 -3827.

AMA Style

Emna Marouani, Noura Ziadi, Vicky Lévesque, Naïma Kolsi Benzina, Besma Bouslimi, Ahmed Koubaa. Mitigation of CO2, CH4 and N2O from Acidic Clayey Soil Amended with Fertilizer Pellets Based on Alkaline Organic Residues. Waste and Biomass Valorization. 2020; 12 (7):3813-3827.

Chicago/Turabian Style

Emna Marouani; Noura Ziadi; Vicky Lévesque; Naïma Kolsi Benzina; Besma Bouslimi; Ahmed Koubaa. 2020. "Mitigation of CO2, CH4 and N2O from Acidic Clayey Soil Amended with Fertilizer Pellets Based on Alkaline Organic Residues." Waste and Biomass Valorization 12, no. 7: 3813-3827.

Journal article
Published: 02 July 2020 in Agronomy
Reads 0
Downloads 0

The use of deinking paper sludge (DPS) as a fertilizer instead of sending it to landfill could play a role in reducing greenhouse gases and improving soil properties. The objectives of this study were (1) to evaluate the changes in the physical (permeability and structural stability), chemical (particularly soil pH), and biological (microbial metabolic quotient (qCO2), microbial biomass soil CO2 emissions) of a calcareous agricultural soil following two successive annual amendments with three treatments (0, 30, and 60 Mg DPS ha−1—control, DPS30, and DPS60, respectively); and (2) to determine whether the addition of N-fertilizer to these treatments (controlF, DPS30F, and DPS60F, respectively) causes changes to soil fertility. The DPS application increased soil organic matter (+0.80%: DPS60 vs. control; and +0.35%: controlF vs. DPS60F), available phosphorus (+23.14 mg kg−1: DPS60 vs. control; and +14.34 mg kg−1: DPS60F vs. controlF), potassium (+0.6 g kg−1: controlF vs. DPS30F), and calcium (+0.28 g kg−1: DPS60 vs. control). The 60 Mg DPS ha−1 rate improved permeability and structural stability, regardless of the presence or absence of N-fertilizer. On the other hand, the 60 Mg DPS ha−1 rate without N-fertilizer lead to a decrease in total mineralization rate and qCO2, thereby indicating a reduction in CO2 emissions. The rate of 60 Mg ha−1 DPS could be effectively used to enhance the permeability and stability (soil restoration) and mitigate CO2 emissions, whereas the 30 Mg ha−1 rate could be used as fertilizer to improve the fertility of calcareous soils.

ACS Style

Emna Marouani; Naïma Kolsi Benzina; Noura Ziadi; Besma Bouslimi; Khouloud Abida; Hanen Tlijani; Ahmed Koubaa. CO2 Emission and Change in the Fertility Parameters of a Calcareous Soil Following Annual Applications of Deinking Paper Sludge (The Case of Tunisia). Agronomy 2020, 10, 956 .

AMA Style

Emna Marouani, Naïma Kolsi Benzina, Noura Ziadi, Besma Bouslimi, Khouloud Abida, Hanen Tlijani, Ahmed Koubaa. CO2 Emission and Change in the Fertility Parameters of a Calcareous Soil Following Annual Applications of Deinking Paper Sludge (The Case of Tunisia). Agronomy. 2020; 10 (7):956.

Chicago/Turabian Style

Emna Marouani; Naïma Kolsi Benzina; Noura Ziadi; Besma Bouslimi; Khouloud Abida; Hanen Tlijani; Ahmed Koubaa. 2020. "CO2 Emission and Change in the Fertility Parameters of a Calcareous Soil Following Annual Applications of Deinking Paper Sludge (The Case of Tunisia)." Agronomy 10, no. 7: 956.

Review article
Published: 18 June 2020 in Chemosphere
Reads 0
Downloads 0

Owing to the seriousness of the ecological risk and human hazard of inorganic wood preservatives, their effective removal was gradually recognized. This paper details different types of wood preservatives, their perniciousness, and their potential removal alternatives, while the wood treatment process is briefly described. Among decontamination methods, microbial remediation is considered as an environmentally friendly approach with enormous potentialities over the conventional treatments. In the current review, the mechanism of bioremediation is summed up and recent advances, challenges, and future perspectives of microbial remediation are discussed. The removal of heavy metals from treated wood requires a combination of various technologies to obtain higher performance. Meanwhile, the decontaminated wood generated through bioremediation can be effectively reused.

ACS Style

Dan Xing; Sara Magdouli; Jingfa Zhang; Ahmed Koubaa. Microbial remediation for the removal of inorganic contaminants from treated wood: Recent trends and challenges. Chemosphere 2020, 258, 127429 .

AMA Style

Dan Xing, Sara Magdouli, Jingfa Zhang, Ahmed Koubaa. Microbial remediation for the removal of inorganic contaminants from treated wood: Recent trends and challenges. Chemosphere. 2020; 258 ():127429.

Chicago/Turabian Style

Dan Xing; Sara Magdouli; Jingfa Zhang; Ahmed Koubaa. 2020. "Microbial remediation for the removal of inorganic contaminants from treated wood: Recent trends and challenges." Chemosphere 258, no. : 127429.

Journal article
Published: 14 March 2020 in Materials
Reads 0
Downloads 0

The physical and mechanical properties of wood (WPC) and biochar polymer composites (BPC) obtained at different pyro-gasification temperatures and different fiber proportions were investigated. Composite pellets made from wood chips or biochar and thermoplastic polymers (polypropylene or high-density polyethylene) were obtained by twin-screw extrusion, and test specimens were prepared by injection molding. Results showed that BPCs were more dimensionally stable compared to WPCs, but their mechanical properties decreased with increasing pyro-gasification temperatures due to the poor adhesion between the polymer and biochar. Indeed, FTIR investigations revealed the decrease or absence of hydroxyl groups on biochar, which prevents the coupling agent from reacting with the biochar surface. The change in the biochar chemical structure led to an improvement in the dimensional stability and hydrophobicity of the biocomposites. Despite the increased dimensional stability of BPCs compared to WPCs, BPCs still adsorb water. This was explained by the surface roughness and by the biochar agglomerations present in the composite. In conclusion, the thermochemical conversion of black spruce wood chips into biochar makes it brittle but more hydrophobic, thereby reducing the wettability of the BPCs.

ACS Style

Ramzi Ayadi; Ahmed Koubaa; Flavia Braghiroli; Sébastien Migneault; He Wang; Chedly Bradai. Effect of the Pyro-Gasification Temperature of Wood on the Physical and Mechanical Properties of Biochar-Polymer Biocomposites. Materials 2020, 13, 1327 .

AMA Style

Ramzi Ayadi, Ahmed Koubaa, Flavia Braghiroli, Sébastien Migneault, He Wang, Chedly Bradai. Effect of the Pyro-Gasification Temperature of Wood on the Physical and Mechanical Properties of Biochar-Polymer Biocomposites. Materials. 2020; 13 (6):1327.

Chicago/Turabian Style

Ramzi Ayadi; Ahmed Koubaa; Flavia Braghiroli; Sébastien Migneault; He Wang; Chedly Bradai. 2020. "Effect of the Pyro-Gasification Temperature of Wood on the Physical and Mechanical Properties of Biochar-Polymer Biocomposites." Materials 13, no. 6: 1327.

Journal article
Published: 16 November 2019 in Forests
Reads 0
Downloads 0

Essential oils (EOs) are natural and economically valuable aromatic compounds obtained from a variety of crops and trees, including forest trees, which have different therapeutic and biological activities. This project aims to assess the impact of different residual forest biomass pretreatments on the yield and the properties of EOs, including their antibacterial and antioxidant characteristics. Forest biomass from black spruce (BS, Picea mariana Mill.), balsam fir (BF, Abies balsamea), and jack pine (JP, Pinus banksiana Lamb.) was processed mechanically by (i) shredding, (ii) grinding, (iii) pelletizing, and (iv) bundling. EOs were then extracted by hydro- and steam distillation. The densification into bundles was found to improve EOs yield compared to the other residual forest biomass pretreatments. For example, the yield of bundled BF was improved by 68%, 83%, and 93% compared to shredded, ground, and granulated biomass, respectively. The highest yield was obtained when densification into bundles was combined with extraction through hydrodistillation. As for EOs’ chemical composition, JP had the highest polyphenol content and consequently the greatest antioxidant activity. EOs derived from BS inhibited the growth of Gram-positive Staphylococcus aureus bacteria and Gram-negative Salmonella typhimurium and Escherichia coli bacteria. The densification of forest biomass into bundles did not affect the antioxidant capacity or the antibacterial activity of EOs, thereby preserving both properties. Thus, the pretreatment of forest biomass residue could have an impact on the volume and the transport costs and therefore improve the bioproducts market and the bioeconomy in Canada.

ACS Style

Mayssa Hmaied; Hassine Bouafif; Sara Magdouli; Flavia Lega Braghiroli; Ahmed Koubaa. Effect of Forest Biomass Pretreatment on Essential Oil Yield and Properties. Forests 2019, 10, 1042 .

AMA Style

Mayssa Hmaied, Hassine Bouafif, Sara Magdouli, Flavia Lega Braghiroli, Ahmed Koubaa. Effect of Forest Biomass Pretreatment on Essential Oil Yield and Properties. Forests. 2019; 10 (11):1042.

Chicago/Turabian Style

Mayssa Hmaied; Hassine Bouafif; Sara Magdouli; Flavia Lega Braghiroli; Ahmed Koubaa. 2019. "Effect of Forest Biomass Pretreatment on Essential Oil Yield and Properties." Forests 10, no. 11: 1042.

Journal article
Published: 14 November 2019 in Forests
Reads 0
Downloads 0

In this work, we examine the effects of commercial thinning on stand volume and individual stem form in nine naturally regenerated black spruce (Picea mariana (Mill.) B.S.P.) stands. We compared these study sites with controls in the commercial boreal forest of northern Quebec, Canada. At stand level, dendrochronological data provided insight into changes in stand volume ten years after thinning. Analysis of a subsample of six individual trees from each commercially thinned stand and three individual trees from the controls illustrated the role of thinning on stem shape development. Although average volume increased for residual stems in thinned stands slightly more than in the controls (110% versus 106%), the treatment effect stand-level volume increment or stand-level total volume harvested (ten years after treatment) was not statistically significant. Moreover, at tree level, thinning did not significantly affect stem volume increment. However, radial growth increment significantly increased after treatment. Trees from commercially thinned stands showed a significantly higher growth increment along the lower first two-thirds of the stem. Response to thinning at tree level correlated strongly with the size and number of harvested competitors around a residual stem. We conclude that commercial thinning modified wood allocation rather than wood volume and did not affect taper and stem shape. These patterns of post-cutting growth are explained by wood allocation following thinning. After commercial thinning, growth increment is favored at the expense of height growth. As the treatment effect was found at the stem scale rather than at the stand scale, further research is needed in regard to commercial thinning treatments to investigate how to increase productivity at the stand scale.

ACS Style

Manon Vincent; Cornelia Krause; Ahmed Koubaa. Influence of Stem Taper on the Yield of Black Spruce Stands and Trees Following Commercial Thinning. Forests 2019, 10, 1024 .

AMA Style

Manon Vincent, Cornelia Krause, Ahmed Koubaa. Influence of Stem Taper on the Yield of Black Spruce Stands and Trees Following Commercial Thinning. Forests. 2019; 10 (11):1024.

Chicago/Turabian Style

Manon Vincent; Cornelia Krause; Ahmed Koubaa. 2019. "Influence of Stem Taper on the Yield of Black Spruce Stands and Trees Following Commercial Thinning." Forests 10, no. 11: 1024.

Journal article
Published: 05 November 2019 in Forests
Reads 0
Downloads 0

So far, few studies have considered the impacts of seed sources transfer on jack pine (Pinus banksiana Lamb.) wood quality, although wood quality attributes (WQA) in general and the differences between juvenile and mature wood in particular will determine suitability of the produced wood for end-uses. The main objective of this study was to examine the possibility of selecting superior jack pine provenances based on selected WQA. Twenty-two provenances of jack pine were planted in 1964 in Petawawa Research Forest, ON, Canada, as part of a provenance test. The plantation location offers conditions close to optimum for jack pine growth. Transition ages at breast height, determined with tracheids length, were computed with a piecewise model. Measurements at age 42 from seed were subjected to analyses of variance. Radial variations from pith to bark, as well as trends with seed sources origin of the selected WQA were also considered. A ranking was made based on a selection index built with four WQA. The provenances matured between 8 and 14 years, corresponding to 17%–48% of juvenile wood proportion. Significant differences among provenances were observed for ring width, ring density, tracheid length, and diameter at breast height but not for tracheid diameter, tree height, transition age, and juvenile wood proportion. None of the provenances ranked the best with all the selected WQA, but it was possible to find provenances exhibiting both high growth rate and good wood quality. A surprising result of this study was that tracheid diameter initially enlarged for 8 years, before declining toward the bark. It is possible to select provenances for a higher growth rate and for good physical (i.e., related to wood density) and anatomical (i.e., related to tracheid dimensions) wood quality attributes.

ACS Style

Cyriac S. Mvolo; Ahmed Koubaa; Jean Beaulieu; Alain Cloutier. Effect of Seed Transfer on Selected Wood Quality Attributes of Jack Pine (Pinus banksiana Lamb.). Forests 2019, 10, 985 .

AMA Style

Cyriac S. Mvolo, Ahmed Koubaa, Jean Beaulieu, Alain Cloutier. Effect of Seed Transfer on Selected Wood Quality Attributes of Jack Pine (Pinus banksiana Lamb.). Forests. 2019; 10 (11):985.

Chicago/Turabian Style

Cyriac S. Mvolo; Ahmed Koubaa; Jean Beaulieu; Alain Cloutier. 2019. "Effect of Seed Transfer on Selected Wood Quality Attributes of Jack Pine (Pinus banksiana Lamb.)." Forests 10, no. 11: 985.

Review
Published: 30 August 2019 in Waste and Biomass Valorization
Reads 0
Downloads 0

Biochar is a carbon-rich organic material that has advantageous physicochemical properties for applications in multidisciplinary areas of science and engineering, including soil amendment, carbon sequestration, bioenergy production, and site rehabilitation. However, the typically low porosity and surface area of biochars (from 0.1 to 500 m2 g−1) limits the suitability for other applications, such as catalysis, electrochemistry, energy storage, and contaminant sorption in drinking water and wastewater. Given the high global demand for activated carbon products, scientists and industrialists are exploring the potential of biochar-derived biomass as precursors for activated carbons. This review presents and discusses the available studies on activated biochars produced from various precursor feedstocks and under different operating conditions in a two-step procedure: pyro-gasification (torrefaction, slow to flash pyrolysis, and gasification) followed by activation (physical, chemical or physicochemical). Findings from several case studies demonstrate that lignocellulosic residues provide attractive precursors, and that chemical activation of the derived biochars at high temperature and long residence time produces highly porous end materials. Indeed, the porosity of activated biochars varies greatly (from 200 to 2500 m2 g−1), depending on the pyro-gasification operating conditions and the feedstock (different feedstocks have distinct morphological and chemical structures). The results also indicate that the development of highly porous activated biochars for diverse purposes (e.g., electrodes for electrochemical energy storage devices, catalyst supports and adsorbents for water treatment) would benefit both the bioeconomy and the environment. Notably, it would leverage the potential of added-value biomass as an economical, non-fossil, readily available, and renewable energy source.

ACS Style

Flavia Lega Braghiroli; Hassine Bouafif; Carmen Mihaela Neculita; Ahmed Koubaa. Influence of Pyro-Gasification and Activation Conditions on the Porosity of Activated Biochars: A Literature Review. Waste and Biomass Valorization 2019, 11, 5079 -5098.

AMA Style

Flavia Lega Braghiroli, Hassine Bouafif, Carmen Mihaela Neculita, Ahmed Koubaa. Influence of Pyro-Gasification and Activation Conditions on the Porosity of Activated Biochars: A Literature Review. Waste and Biomass Valorization. 2019; 11 (9):5079-5098.

Chicago/Turabian Style

Flavia Lega Braghiroli; Hassine Bouafif; Carmen Mihaela Neculita; Ahmed Koubaa. 2019. "Influence of Pyro-Gasification and Activation Conditions on the Porosity of Activated Biochars: A Literature Review." Waste and Biomass Valorization 11, no. 9: 5079-5098.

Journal article
Published: 27 August 2019 in Construction and Building Materials
Reads 0
Downloads 0

Continuous-fiber reinforced WPCs were prepared using an extruder with a special die. The effects of the amount (1–7 bundles) and type of fiber (aramid rovings and yarns and carbon and glass yarns) on the mechanical properties of WPCs were studied. The addition of continuous fibers increased the tensile, flexural and impact strength of the composites by up to 47.3%, 83.1% and 713.4%, respectively. The damping ratio analysis revealed that the interfacial bonding of glass-yarn reinforced WPCs was the best among the tested samples. Adding continuous fibers to WPCs at a low volume fraction can promote their use as load-bearing engineered materials.

ACS Style

Jingfa Zhang; Yue Li; Dan Xing; Qingwen Wang; Haigang Wang; Ahmed Koubaa. Reinforcement of continuous fibers for extruded wood-flour/HDPE composites: Effects of fiber type and amount. Construction and Building Materials 2019, 228, 116718 .

AMA Style

Jingfa Zhang, Yue Li, Dan Xing, Qingwen Wang, Haigang Wang, Ahmed Koubaa. Reinforcement of continuous fibers for extruded wood-flour/HDPE composites: Effects of fiber type and amount. Construction and Building Materials. 2019; 228 ():116718.

Chicago/Turabian Style

Jingfa Zhang; Yue Li; Dan Xing; Qingwen Wang; Haigang Wang; Ahmed Koubaa. 2019. "Reinforcement of continuous fibers for extruded wood-flour/HDPE composites: Effects of fiber type and amount." Construction and Building Materials 228, no. : 116718.

Journal article
Published: 08 August 2019 in Waste Management & Research: The Journal for a Sustainable Circular Economy
Reads 0
Downloads 0

Thermal composting is an important and useful way to transfer raw organic matter into value-added product rich in humic substances. Furthermore, thermal composting is a very promising way to reduce deinking paper sludge pollutions, which are difficult to remove. The objective of this study was to investigate the behaviour of the composting process of deinking paper sludge with poultry manure over 14 months. Two composts were used: C1 (70/30: deinking paper sludge/poultry manure) and C2 (50/50: deinking paper sludge/poultry manure). The compost stability and maturity were assessed via physico–chemical and thermal analyses: thermogravimetric analysis, differential thermal analysis and diffuse reflectance infrared Fourier transform spectroscopy. Diffuse reflectance infrared Fourier transform spectroscopy analysis provided chemical information for the presence of aromatic, phenolic, aliphatic and polysaccharidic structures. Thermogravimetry analyses revealed that both deinking paper sludge composts were rich in humic acids. The ratio E4/E6 (fulvic acids/humic acids) was also carried out to characterise the maturity index of composts. After 14 months, the compost C2 is more stable, mature and rich in humic acids than compost C1. Furthermore, the addition of poultry manure to the deinking paper sludge-based composts enhanced the formation of humic substances. From 0 to 14 months of composting, the concentration of polychlorinated biphenyls decreased from 0.2 to 0.1 mg kg−1 and from 0.6 to 0.2 mg kg−1 for C1 and C2, respectively.

ACS Style

Emna Marouani; Naïma Kolsi Benzina; Noura Ziadi; Besma Bouslimi; Amani Abouda; Ahmed Koubaa. Deinking sludge compost stability and maturity assessment using Fourier transform infrared spectroscopy and thermal analysis. Waste Management & Research: The Journal for a Sustainable Circular Economy 2019, 37, 1043 -1057.

AMA Style

Emna Marouani, Naïma Kolsi Benzina, Noura Ziadi, Besma Bouslimi, Amani Abouda, Ahmed Koubaa. Deinking sludge compost stability and maturity assessment using Fourier transform infrared spectroscopy and thermal analysis. Waste Management & Research: The Journal for a Sustainable Circular Economy. 2019; 37 (10):1043-1057.

Chicago/Turabian Style

Emna Marouani; Naïma Kolsi Benzina; Noura Ziadi; Besma Bouslimi; Amani Abouda; Ahmed Koubaa. 2019. "Deinking sludge compost stability and maturity assessment using Fourier transform infrared spectroscopy and thermal analysis." Waste Management & Research: The Journal for a Sustainable Circular Economy 37, no. 10: 1043-1057.

Article
Published: 22 July 2019 in Water, Air, & Soil Pollution
Reads 0
Downloads 0

The increasing global demand for metals and minerals justifies the intensive study of treatment options for contaminated mine effluents. The present study evaluated the conversion of wood residues into physically and chemically activated biochars and their subsequent use in the treatment of Cu in synthetic and actual contaminated mine drainage. First, wood residues were converted into biochar by fast pyrolysis. Then, physical (using steam or CO2) or chemical (using KOH) activation was carried out in a homemade pilot-scale furnace. After activation, highly microporous (KOH materials) and micro/mesoporous activated biochars (CO2 and steam materials) were obtained. Batch adsorption testing was first conducted with synthetic effluents. Results showed that CO2-activated biochar was the most Cu effective adsorbent (99% removal) at low concentrations (5–20 mg L−1). The mechanisms of Cu2+ adsorption involved physical and chemisorption for biochars and CO2-activated biochar, while chemisorption for KOH-activated biochars was probably due to the high proportion of functional groups connected to their surface. In multi-metal acid mine drainage, metal adsorption capacities deteriorated for most of the materials, probably due to the effects of ion competition. However, KOH-activated biochar decreased Cu2+ concentrations to below the authorized monthly mean allowed by Canadian law (0.3 mg L−1) and decreased Co, Pb, and Mn concentrations up to 95%. These findings indicate that high porosity and oxygenated functional groups connected to the surface of activated biochars are important properties for the enhancement of interactions between carbon materials and metals from mine effluents, as well as for their performance improvement in mine drainage treatment.

ACS Style

Flavia Lega Braghiroli; Hassine Bouafif; Carmen Mihaela Neculita; Ahmed Koubaa. Performance of Physically and Chemically Activated Biochars in Copper Removal from Contaminated Mine Effluents. Water, Air, & Soil Pollution 2019, 230, 1 -14.

AMA Style

Flavia Lega Braghiroli, Hassine Bouafif, Carmen Mihaela Neculita, Ahmed Koubaa. Performance of Physically and Chemically Activated Biochars in Copper Removal from Contaminated Mine Effluents. Water, Air, & Soil Pollution. 2019; 230 (8):1-14.

Chicago/Turabian Style

Flavia Lega Braghiroli; Hassine Bouafif; Carmen Mihaela Neculita; Ahmed Koubaa. 2019. "Performance of Physically and Chemically Activated Biochars in Copper Removal from Contaminated Mine Effluents." Water, Air, & Soil Pollution 230, no. 8: 1-14.

Journal article
Published: 16 July 2019 in Forests
Reads 0
Downloads 0

We examined phenotypic relationships among radial growth-related, physical (i.e., related to wood density), and anatomical (i.e., related to tracheid dimensions) wood properties in white spruce (Picea glauca (Moench) Voss), in order to determine the strength and significance of their correlations. Additionally, principal component analysis (PCA) was used to establish if all of the properties must be measured and to determine the key properties that can be used as proxies for the other variables. Radial growth-related and physical properties were measured with an X-ray densitometer, while anatomical properties were measured with a Fiber Quality Analyzer. Fifteen wood properties (tracheid length (TL) and diameter (TD), earlywood tracheid length (ETL) and diameter (ETD), latewood tracheid length (LTL) and diameter (LTD), ring width (RW), ring area (RA), earlywood width (EWW), latewood width (LWW), latewood proportion (LWP), ring density (RD), intra-ring density variation, earlywood density (EWD), and latewood density (LWD)) were assessed. Relationships were evaluated at intra-ring and inter-ring levels in the juvenile wood (JW) and mature wood (MW) zones. Except for a few cases when mature tracheid diameter (TD) was involved, all intra-ring anatomical properties were highly and significantly correlated. Radial growth properties were correlated, with stronger relationships in MW compared to JW. Physical properties were often positively and significantly correlated in both JW and MW. A higher earlywood density coupled with a lower latewood density favored wood uniformity, i.e., the homogeneity of ring density within a growth ring. Managing plantations to suppress trees growth during JW formation, and enhancing radial growth when MW formation starts will favor overall wood quality. In order, RW-EWW-RA, TL-ETL-LTL, and RD-EWD-LWP are the three clusters that appeared in the three wood zones, the whole pith-to-bark radial section, the juvenile wood zone, and the mature wood zone.

ACS Style

Cyriac S. Mvolo; Ahmed Koubaa; Jean Beaulieu; Alain Cloutier; Maurice Defo; Martin-Claude Yemele. Phenotypic Correlations among Growth and Selected Wood Properties in White Spruce (Picea glauca (Moench) Voss) †. Forests 2019, 10, 589 .

AMA Style

Cyriac S. Mvolo, Ahmed Koubaa, Jean Beaulieu, Alain Cloutier, Maurice Defo, Martin-Claude Yemele. Phenotypic Correlations among Growth and Selected Wood Properties in White Spruce (Picea glauca (Moench) Voss) †. Forests. 2019; 10 (7):589.

Chicago/Turabian Style

Cyriac S. Mvolo; Ahmed Koubaa; Jean Beaulieu; Alain Cloutier; Maurice Defo; Martin-Claude Yemele. 2019. "Phenotypic Correlations among Growth and Selected Wood Properties in White Spruce (Picea glauca (Moench) Voss) †." Forests 10, no. 7: 589.