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  • 1
    Language: English
    In: Water, air, and soil pollution, 2018-06-28, Vol.229 (7), p.1-22
    Description: Adsorption is acknowledged as effective for the removal of pollutants from drinking water and wastewater. Biochar, as a widely available material, holds promises for pollutant adsorption. So far, biochar has been found to be effective for multiple purposes, including carbon sequestration, nutrient storage, and water-holding capacity. However, its limited porosity restricts its use in water treatment. Activation of biochars, when performed at a high temperature (i.e., 900 °C) and in the presence of certain chemicals (H 3 PO 4 , KOH) and/or gases (CO 2 , steam), improves the development of porosity through the selective gasification of carbon atoms. Physicochemical activation process is appropriate for the production of highly porous materials. As well, the morphological and chemical structure of feedstock together with pyro-gasification operating conditions for the biochar production can greatly impact the porosity of the final materials. The effectiveness of activated biochar as adsorbent depends on porosity and on some functional groups connected to its structure, both of these are developed during activation. This study provides a comprehensive synthesis of the effect of several activated biochars when applied to the treatment of organic and inorganic contaminants in water. Results show that high aromaticity and porosity are essential for the sorption of organic contaminants, while the presence of oxygen-containing functional groups and optimum pH are crucial for the sorption of inorganic contaminants, especially metals. Finally, although activated biochar is a promising option for the treatment of contaminants in water, further research is required to evaluate its performance with real effluents containing contaminants of emerging concern. Graphical abstract ᅟ
    Subject(s): Activation ; Adsorption ; Article ; Atmospheric Protection/Air Quality Control/Air Pollution ; Biochar ; Biomass waste ; Climate Change/Climate Change Impacts ; Drinking water ; Earth and Environmental Science ; Environment ; Environment, general ; general ; Hydrogeology ; Organic and inorganic contaminants ; Porosity ; Soil Science & Conservation ; Wastewater ; Water pollution ; Water Quality/Water Pollution ; Water treatment
    ISSN: 0049-6979
    E-ISSN: 1573-2932
    Source: Alma/SFX Local Collection
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  • 2
    Language: English
    In: Water, air, and soil pollution, 2019-07-22, Vol.230 (8), p.1-14
    Description: 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 CO 2 ) 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 (CO 2 and steam materials) were obtained. Batch adsorption testing was first conducted with synthetic effluents. Results showed that CO 2 -activated biochar was the most Cu effective adsorbent (99% removal) at low concentrations (5–20 mg L −1 ). The mechanisms of Cu 2+ adsorption involved physical and chemisorption for biochars and CO 2 -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 Cu 2+ 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.
    Subject(s): Acid mine drainage ; Activated biochar ; Actual mine effluents ; Adsorption ; Article ; Atmospheric Protection/Air Quality Control/Air Pollution ; Climate Change/Climate Change Impacts ; Copper industry ; Copper removal ; Earth and Environmental Science ; Environment ; Environment, general ; Environmental Sciences ; Environmental Sciences & Ecology ; general ; Hydrogeology ; Life Sciences & Biomedicine ; Meteorology & Atmospheric Sciences ; Physical Sciences ; Science & Technology ; Soil Science & Conservation ; Water Quality/Water Pollution ; Water Resources ; Water treatment
    ISSN: 0049-6979
    E-ISSN: 1573-2932
    Source: Web of Science - Science Citation Index Expanded - 2019〈img src="http://exlibris-pub.s3.amazonaws.com/fromwos-v2.jpg" /〉
    Source: Alma/SFX Local Collection
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  • 3
    Language: English
    In: Materials & design, 2020-06, Vol.191, p.108589
    Description: The preparation of bio-composites based on engineering plastic is always restricted by the low thermal stability of lignocellulose. In this study, the thermal stability of lignocellulose was improved by boric acid modification. Then, the borated lignocellulose was characterized to analyze the mechanism of involved in the improvement of thermal stability. Furthermore, the untreated and borated lignocellulose was combined with polyamide 6 to produce bio-composites. The effects of lignocellulose content and boric acid modification on the color, thermal stability and mechanical properties of the resulting composites were compared and analyzed. Boric acid protected lignocellulose from thermal degradation, increasing the lightness of the resulting composites. However, boric acid appeared to have a negative effect on the mechanical strength of the resulting composites. In summary, this study demonstrated that bio-composites based on engineering plastic could be prepared by improving the thermal stability of lignocellulose using a boric acid treatment. [Display omitted] •Bio-composites based on engineering plastic were prepared by improving the thermal stability of lignocellulose.•The thermal stability of lignocellulosic fiber was improved by boric acid modification.•The chemical structure of lignocellulose changed because of the complexation reaction between boric acid and lignocellulose.•Boric acid has a positive effect on the physical properties of the composites.
    Subject(s): Boric acid modification ; Lignocellulose ; Polyamide 6 ; Polymer-matrix composites ; Thermal stability
    ISSN: 0264-1275
    E-ISSN: 1873-4197
    Source: DOAJ Directory of Open Access Journals - Not for CDI Discovery
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  • 4
    Language: English
    In: Journal of applied polymer science, 2018-07-20, Vol.135 (28), p.n/a
    Description: ABSTRACT A comparative study was conducted of composites made with sludge from three different paper mills. Sludges were obtained from a thermomechanical pulp (TMP), a chemico‐TMP (CTMP), and a Kraft mill with a feedstock of primarily black spruce. The primary sludge (PS) and secondary sludge (SS) were mixed at two different ratios (PS:SS = 7:3 and 9:1) and blended with high‐density polyethylene (HDPE) at 20%, 30%, and 40% proportion. The blends were tested using plate–plate geometry before subjection to frequency sweep by oscillation rheometry. The storage modulus (G′), loss modulus (G″), and complex viscosity (η*) increased with increasing paper sludge content. Decreasing the PS:SS ratio from 9:1 to 7:3 decreased G′, G″, and η*. Differential scanning calorimetry showed that sludge addition increased both the melting and crystallization temperature, for a positive effect on crystallinity. Although the behavior of sludge–high‐density polyethylene blends differed from that of traditional wood plastic composite made with wood flour, they obtained G′, G″, and η* values of the same magnitude. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46484.
    Subject(s): differential scanning calorimetry (DSC) ; fibers ; Paper industry ; Paper mills ; Polyethylene ; rheology ; Sludge ; thermoplastics
    ISSN: 0021-8995
    E-ISSN: 1097-4628
    Source: Alma/SFX Local Collection
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  • 5
    Language: English
    In: Environmental science and pollution research international, 2018-07-11, Vol.25 (26), p.26562-26575
    Description: There is growing interest in low-cost, efficient materials for the removal of organic contaminants in municipal and industrial effluents. In this study, the efficiency of biochar and activated biochar, as promising adsorbents for phenol removal, was investigated at high (up to 1500 mg L −1 ) and low concentrations (0.54 mg L −1 ) in synthetic and real effluents (from wood-residue deposits in Québec), respectively. The performance of both materials was then evaluated in batch adsorption experiments, which were conducted using a low solid/liquid ratio (0.1 g:100 mL) at different phenol concentrations ( C 0  = 5–1500 mg L −1 ), and at 20 °C. Activated biochars presented higher phenol adsorption capacity compared to biochars due to their improved textural properties, higher micropore volume, and proportion of oxygenated carbonyl groups connected to their surface. The sorption equilibrium was reached within less than 4 h for all of materials, while the Langmuir model best described their sorption process. The maximum sorption capacity of activated biochars for phenol was found to be twofold relative to biochars (303 vs. 159 mg g −1 ). Results also showed that activated biochars were more effective than biochars in removing low phenol concentrations in real effluents. In addition, 95% of phenol removal was attained within 96 h (although 85% was removed after 4 h), thus reaching below the maximum authorized concentration allowed by Québec’s discharge criteria (0.05 mg L −1 ). These results show that activated biochars made from wood residues are promising potential adsorbent materials for the efficient treatment of phenol in synthetic and real effluents.
    Subject(s): Activated biochar ; Adsorption ; Analysis ; Aquatic Pollution ; Atmospheric Protection/Air Quality Control/Air Pollution ; Biochar ; Earth and Environmental Science ; Ecotoxicology ; Environment ; Environment, general ; Environmental Chemistry ; Environmental Health ; general ; Lumber industry ; Lumber industry sites ; Phenol removal ; Purification ; Research Article ; Sewage ; Synthetic and real effluents ; Waste Water Technology ; Waste Water Technology / Water Pollution Control / Water Management / Aquatic Pollution ; Water Management ; Water Pollution Control ; Water treatment
    ISSN: 0944-1344
    E-ISSN: 1614-7499
    Source: Alma/SFX Local Collection
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  • 6
    Language: English
    In: Energies (Basel), 2021-10-12, Vol.14 (20), p.6529
    Description: Thermal treatments such as torrefaction and fast pyrolysis are commonly employed methods to produce biofuels with high-energetic properties. In this study, wood chips were heat-treated at different temperatures of torrefaction (315 °C) and fast pyrolysis (400 and 454 °C) to form energetic pellets. Three softwoods, jack pine (JP), balsam fir (BF), and black spruce (BS), were evaluated. Pellets are produced using 20% moisture content and 15% pyrolytic lignin as a binder. Untreated- and treated-wood residues were characterized by surface chemistry, elemental analysis, and chemical composition, whereas all pellets were characterized in terms of density, high heat value (HHV), and durability. Results showed that both thermal treatments caused significant changes in the physicochemical structure of wood residues. Using temperatures higher than 315 °C leads to the disappearance of hydroxyl groups, a decrease in oxygen and hydrogen contents, and an increase in carbon content. Regardless of the treatment temperature, pellets made from heat-treated JP had the best durability (93%). In contrast, the calorific values of wood-treated pellets reached up to 31 MJ/kg, compared to untreated-wood pellets (19 MJ/kg). Thus, the densification of the thermal-treated wood residues represents a potential approach for producing biofuels with high energetic value.
    Subject(s): fast pyrolysis ; pellets ; pyrolytic lignin ; thermal treatment ; torrefaction ; wood residues
    ISSN: 1996-1073
    E-ISSN: 1996-1073
    Source: Academic Search Ultimate
    Source: Alma/SFX Local Collection
    Source: DOAJ Directory of Open Access Journals - Not for CDI Discovery
    Source: ProQuest Central
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  • 7
    Language: English
    In: Polymer composites, 2017-08, Vol.38 (8), p.1749-1755
    Description: Wood flour (WF)‐filled composites based on a polypropylene (PP)/recycled polyethylene terephthalate (r‐PET) matrix were prepared using two‐step extrusion. Maleic anhydride grafted polypropylene (MAPP) was added to improve the compatibility between polymer matrices and WF. The effects of filler and MAPP compatibilization on the water absorption, mechanical properties, and morphological features of PP/r‐PET/WF composites were investigated. The addition of MAPP significantly improved mechanical properties such as tensile strength, flexural strength, tensile modulus, and flexural modulus compared with uncompatibilized composites, but decreased elongation at break. Scanning electron microscopic images of fracture surface specimens revealed better interfacial interaction between WF and polymer matrix for MAPP‐compatibilized PP/r‐PET/WF composites. MAPP‐compatibilized PP/r‐PET/WF composites also showed reduced water absorption due to improved interfacial bonding, which limited the amount of absorbable water molecules. These results indicated that MAPP acts as an effective compatibilizer in PP/r‐PET/WF composites. POLYM. COMPOS., 38:1749–1755, 2017. © 2015 Society of Plastics Engineers
    Subject(s): Ethylene ; Mechanical properties ; Polyethylene terephthalate
    ISSN: 0272-8397
    E-ISSN: 1548-0569
    Source: Academic Search Ultimate
    Source: Alma/SFX Local Collection
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  • 8
    Language: English
    In: Annals of operations research, 2016-05-02, Vol.248 (1-2), p.515-529
    Description: We transformed a data envelopment analysis (DEA) optimization model into a robust second-order cone equivalent to immunize against output perturbation in an uncertainty set. The robust DEA framework was then used to assess the effect of a wood hardening treatment using methyl methacrylate (MMA) on selected hybrid poplar clones. Because the performance of MMA-hardened hybrid poplar clones varies across clones, ranking hardened clones is crucial for developing hardening treatments for specific industrial applications. The numerical results demonstrate that the hardening treatment can be optimized by applying the proposed DEA framework to select the best hybrid poplar clone types and the optimal amount of impregnated chemicals.
    Subject(s): Business and Management ; Combinatorics ; Data envelopment analysis ; Data envelopment analysis (DEA) ; Economics and Business ; Ekonomi och näringsliv ; Evaluation ; Hardening ; Hardness ; Hybrid poplar ; Methods ; Methyl methacrylate ; Methyl methacrylate (MMA) ; Operation Research/Decision Theory ; Operations Research/Decision Theory ; Original Paper ; Poplar ; Robust optimization ; Samhällsvetenskap ; Social Sciences ; Theory of Computation ; Uncertainty
    ISSN: 0254-5330
    ISSN: 1572-9338
    E-ISSN: 1572-9338
    Source: Business Source Ultimate
    Source: Alma/SFX Local Collection
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  • 9
    Language: English
    In: Forests, 2019-11-01, Vol.10 (11), p.1024
    Description: 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.
    Subject(s): Forestry ; Life Sciences & Biomedicine ; Science & Technology
    ISSN: 1999-4907
    E-ISSN: 1999-4907
    Source: Web of Science - Science Citation Index Expanded - 2019〈img src="http://exlibris-pub.s3.amazonaws.com/fromwos-v2.jpg" /〉
    Source: DOAJ Directory of Open Access Journals - Not for CDI Discovery
    Source: ProQuest Central
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  • 10
    Language: English
    In: Materials, 2020-03-14, Vol.13 (6), p.1327
    Description: 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.
    Subject(s): biochar ; biocomposites ; hydrophobicity ; physical and mechanical properties ; pyro-gasification
    ISSN: 1996-1944
    E-ISSN: 1996-1944
    Source: Academic Search Ultimate
    Source: PubMed Central
    Source: DOAJ Directory of Open Access Journals - Not for CDI Discovery
    Source: ProQuest Central
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