Many wood processing industries use short rotation teak, which has lower quality especially in durability and dimensional stability. Heat treatment is an eco-friendly method to improve dimensional stability and durability of wood. The objectives of the study were to investigate the effects of thermal modification on chemical composition, colour, dimensional stability and durability as well as coating’s performance after accelerated weathering of short and long rotation teak for exterior utilization. In this study, the samples were heated in oven at 220 °C for 20 h under nitrogen atmosphere. Results showed that independently of growth conditions teak woods underwent hemicelluloses degradation and an increase of lignin content after heat treatment. Extractives contents were lower in short rotation than in long rotation teak, and decreased in all cases after heat treatments. Dimensional stability was considerably improved as indicated by anti-swelling efficiency values of 64.9% and 58.9% for short and long rotation teak, respectively. Heated teak woods were more resistant against Trametes versicolor and the durability of short-rotation teak increased from moderate to very durable. Coatings on heat treated teaks had better bonding quality and better photo-stability when compared to unheated. Heated short rotation teak could be considered for exterior application.

RÉSUMÉL'élimination du cuivre (Cu2+) par un déchet agricole: la peau d'amande (PA) séchée, broyée et tamisée (granulo: 1.25/2 mm) a été étudiée. Les expériences ont été effectuées sur des solutions aqueuses synthétiques en condition batch. L'influence du temps de contact et de la concentration initiale en métal sur la cinétique de sorption du cuivre a été étudiée. L'étude cinétique a montré que la quantité du métal sorbée à l’équilibre augmente avec l'augmentation du temps de contact et de la concentration initiale en Cu2+ dans la solution. Les courbes de cinétiques suivent parfaitement le modèle cinétique du pseudo second ordre. La diffusion intraparticulaire n'était pas prépondérante dans le processus de sorption du cuivre. Le modèle de Langmuir s'est avéré plus adéquat pour décrire les résultats d'équilibre trouvés comparativement au modèle de Freundlich. La capacité maximale (qmax) de sorption du cuivre obtenue est de 78.25 mg/g (soit 1.23 mmol/L). L'analyse par microscopie électronique à balayage couplée à l'EDAX de la peau d'amande en contact avec le cuivre après équilibre a montré l'existence du cuivre sur la surface du matériau.

The durability of exterior finishes on wood is not assured with the systems currently used. Thus, the objective of this study was to evaluate the color change of the finishes applied to wood, the most commercialized in Morocco, in order to find the wood-finishing couple that has the best durability in outdoor use. QUV accelerated aging tests were carried out during 2016 hours, according to the standard (NF 927-6 2006), on Scots pine (Pinus sylvestris) and Pedunculate oak (Quercus robur) coated with four finishes (two polyurethane finishes F1 and F2 and two acrylic finishes F3 and F4). Colorimetric measurements in color system CIELab: Gloss (L*), green-red (a*) and blue-yellow (b*) coordinates, color saturation (C*) and tone angle (H*) were performed using an X-Rite Model SP62 spectrophotometer before and at the end of the QUV accelerated aging treatment. The results showed that QUV aging caused a decrease in the L* value and a change in the surface color of all the finishing pairs studied. For wood / finishing couples with Quercus robur as a wooden support, the couple Quercus robur / F3 has the best resistance to color change, while for couples wood / finish with Pinus sylvestris as a wooden support, the couple Pinus sylvestris / F1 has the best resistance to color change.

•A rational method is proposed for the mix design of plant aggregates concrete.•The volume of air trapped in this type of concrete is very important.•We cannot ignore such a quantity of air in any formulation process.•The volume of air depends only on the mixing time and the mode of implementation.

Teak ( Tectona grandis L.f.) is one of the most important tropical hardwood tree species, which is widely planted in Indonesia. Wood properties are strongly influenced by forest management conditioning further utilization of wood.

This article proposes a method for the mix design of concretes based on plant aggregates. Its principle consists in determining the packing density of the plant skeleton for a specific mode of implementation and then in proportioning the binder paste which will occupy the residual intergranular pore volume. The paste is consisted of the binder, the effective water, the possible additions and admixture, and trapped air and/or entrained air. For a given volume of air (and additions), the quantities of cement and effective water are then adjusted to achieve the targeted performances, based on the law of Féret. However, for this type of concrete, the large volume of entrained air (also) depends on the quantity of cement and water present in the mixture, the intensity of the mixing and the casting mode. A model describing the residual air volume must then be calibrated from tests carried out with the components of the concrete that it is desired to manufacture. The problem of the formulation can then be solved by using a numerical optimization module. An example applied to a rice husks concrete is presented here.

The aesthetic durability of wooden structures is a major challenge for the use of this material in construction. Wood is used for its technical performances but also for its architectural qualities and its aesthetic perception. The premature aging of the wooden structures is detrimental because these disorders, even if they do not affect the strength of the structures, are mostly irremediable. The surface protection of wood is generally ensured by the use of a finish, whose essential role is to protect wood from climatic aggressions (water, solar radiation, oxygen, ...). The secondary wood processing industry consists of a series of manufacturing and processing activities, each containing a portion of the added value of the product. The application of a finish on a wood-based work is usually the last and most visible step in this value chain.In outdoor use, the protection of the wood surface with transparent finishes is not yet sufficiently durable to be able to compete with materials used in industrial carpentry such as PVC or aluminum. Opaque finishes generally provide more durable protection but they mask the appearance of the wood sought by users.With the aim of positioning wood in this construction sector, research on transparent finishes has focused on the efficiency and improvement of the durability of the protection of the surface appearance of structures. Faced with climatic aggressions, the optimum conservation of a structure is not only linked to the performance of the finish but also to the characteristics of the wood material. In particular, in order to fulfill its protective function, the finish film must be able to follow the dimensional variations of the wood it covers without breaking and without detachment. In addition to the criteria for the effectiveness of finishes in the protection of structures, the environmental impact must be considered with increasing attention. Currently, more than 80% of composite or solid wood products are still protected with solvent-based liquid products, which are an important source of VOC emissions. Does the solution come from photo-polymerizable systems that can be formulated with 100% dry matter either in liquid phase in reactive diluents or powdered?

This study present a composite material made of four thermoplastic polymers and wood sawdust. The wood sawdust of size 630, 315, 160 µm and plastic waste containing 3,91% of polyethylene terephthalate (PET), 87,62% of High-density polyethylene (HDPE), 7,23% of Low-density polyethylene (LDPE) and 1.21% of Polypropylene (PP) have been transformed in composites wood/polymer by extrusion. The mechanical and thermal properties have been studied through tensile test and a thermogravimetric analysis. The weight ratio of the cellulosic materials to polymer matrix was 25:75(w:w). Morphological study was done on the rupture surface on samples to appreciate the adherence of wood sawdust/matrix. The study shows that the presence of the wood sawdust increases the modulus of elasticity (MOE) of the composite by conferring a better rigidity. Also, we see that wood sawdust increases the thermal stability of the composite.

The purpose of our work is the development of a local agricultural waste biomass material, Ziziphus jujuba known as Nebka (NB), into activated carbons to remove humic acid (HA) from aqueous solutions. This was further treated with nitric acid solutions. The surface characteristics of the adsorbent were calculated using the standard Brunauer–Emmet–Teller method (BET). The microstructures of the samples were observed with scanning electron micrographs. Chemical characterization of the samples was carried out by selective titrations and Fourier Transform Infrared Spectroscopy (FT-IR). On the basis of the BET results, we have obtained the best microporous activated carbon oxidized (surface area of 970m2/g, microporous volume of 0.170cm3/g and total pore volume of 0.326cm3/g). Adsorption studies were conducted using a batch process, to study the effects of contact time, pH and temperature. The pH dependent sorption of HA was found maximum at pH range 4–6 for an initial concentration of 50mg/L. The equilibrium adsorption data was analyzed using Langmuir and Freundlich isotherm models, and the kinetic data was analyzed using pseudo-first order and pseudo-second order kinetic models. The equilibrium data were well fitted to the Freundlich isotherm. The adsorption reached equilibrium after 300min and the maximum adsorption capacity was about 76.92mg/g at 20°C according to the Langmuir model. The adsorption kinetic was found to follow the pseudo-second-order kinetic model. Thermodynamic study showed that the adsorption of HA onto oxidized activated carbons was feasible, spontaneous and endothermic at 20–40°C.

Improving the durability of exterior coatings is essential for the use and development of wood as a building material. In Europe, performances of wood coatings are mainly estimated through visual assessments of panels exposed to weathering. The aim of this work was to investigate the Persoz pendulum as a simple tool to gain information on hardness and mechanical properties of exterior wood coatings. The influence of the substrate and the coating thickness has been studied to figure out the limits of the test method. Through a comparison with tensile tests performed on free films, Persoz pendulum was found to be relevant as a simple tool to estimate mechanical properties of the coating film. Finally, Persoz hardness was assessed on several coatings exposed to 4032 h of artificial weathering. Results have shown that the pendulum hardness test is a useful method to study wood coatings performances for outdoors.

Potentially toxic trace elements, such as zinc, with high levels in water are very serious problems in many places around the world, sometimes in relation to natural sources and in other cases to anthropogenic ones. Adsorption process is among the most effective techniques for removing of many heavy metal ions from different types of water. In this study, an attempt has been made to investigate the efficiency of Calotropis procera roots (CP) in removing of Zn(II) from aqueous solution by using batch mode technique. During the removal process, the effects of solution pH, Zn concentrations and contact time on adsorption efficiency by CP roots were studied. Experimental equilibrium data were analyzed by the Langmuir and Freundlich isotherm models. The results showed that the best fit was achieved with the Langmuir isotherm equation with maximum adsorption capacity of 9.69 mg/g. The biosorption of Zn(II) was a fast process and followed the pseudo-second-order kinetic.

In the present study, three varieties (Wild, Fleshy and Sisam) of carob (Ceratonia siliqua L.) pods were analyzed for their bioactive phytochemical content and antioxidant activities (AA) at three ripening stages. The results showed that the samples have the highest total phenolic (TPC), total flavonoid (TFC) and ascorbic acid content (AAC) in the unripe stage. The antioxidant activity examined using free radical scavenging effect against 2-2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing power (FRP) and ferrous iron chelating (FIC) assays decreased significantly throughout the ripening. Extremely significant correlations (p<0.001) were found between phytochemical compound contents (TPC, TFC and AAC) and assessed antioxidant activities, except between AAC and FIC where just a very significant correlation (p<0.01) was recorded. Our data revealed that extracts of unripe C. siliqua L. are an excellent source of natural antioxidants that might be more widely used in cosmetic, pharmaceutical and food industries.

The ability of orange peels (OP) and almond peels (AP) as adsorbents for the removal of a dyestuff, namely methylene blue (MB) from aqueous solutions has been studied. After their characterization by different techniques (elemental analysis, biochemical analysis, IR spectroscopy, thermogravimetric analysis, scanning electron microscopy, mercury porosimetry), adsorption kinetics of the dye have been investigated using common kinetic models cited in the literature: first order and pseudo-second order. The correlation coefficient has showed that the pseudo-second order kinetic equation best describes the adsorption kinetics for the tested materials. The experimental equilibrium data have been analyzed using linearized forms of Langmuir and Freundlich isotherms. The Langmuir isotherm was found to provide the best theoretical correlation of the experimental data whatever the biosorbents tested. Using the equilibrium coefficients obtained at different temperatures, various thermodynamic parameters such as ΔG°, ΔH°, ΔS° have been calculated. The thermodynamics of MB/OP and MB/AP systems indicated spontaneous and endothermic process. It was concluded that an increase in temperature results in a higher MB loading per unit weight of OP or AP.

The effect of thermal treatment and impregnation of woods on the stability of wood colour was investigated. Impregnation was performed by extractives obtained from the same thermally treated species or different ones. Treated and untreated samples were exposed to an accelerating ageing by solar radiation during 1000 h. Resuts showed that thermal treatments improved mainly the colour stability of softwood (pine and white fir) samples. Analysis of chromatic coordinates after 1000 hours of accelerated ageing showed that, thermally treated pine and white fir woods were the least affected samples with E* 1000 = 8.66 and 13.31 respectively. Impregnation increases the component b* causing an intense darkening of all analysed wood samples. Moreover, impregnation stabilised the colour of poplar and fir woods subjected 1000 hours of accelerated ageing whereas, beech woods showed high variations in colour. Thus, thermal treatment and impregnation could stabilise the surface aspect of woods that have an unstable natural colour. The efficiency of impregnation depends on the nature and physicochemical properties of the extractable substances and thus on wood species.

The preparation of antibacterial UV powder coatings dedicated to wood based panels is described in the present study. Two experimental methods were investigated: the generation of silver nanoparticles during the polymerization of UV powders and the introduction of a silver modified beidellite within UV powder formulations. While the first method leads to some nanoparticle aggregation, this phenomenon was avoided with the second approach. Antibacterial activity was thus ensured by the presence of beidellite modified with silver cations. XRD, X-ray fluorescence, SEM/EDX and TEM analyses allowed a complete characterization of the Ag-beidellite before its incorporation within UV powder formulations. Real-time-FTIR spectroscopy fitted with an environmental cell was used to monitor the reactivity of UV powder formulations under UV light and temperature control. Resulting coatings were finally characterized by UV spectroscopy, DMA in tension mode, XRD, TEM and antimicrobial analyses. It was shown that the fully cured and homogeneous coatings exhibit high thermomechanical properties and antibacterial activity.

Cetyltrimethylammonium bromide-modified kaolin (CTAB-kaolin or KC) was prepared and tested as an adsorbent for an anionic dye Congo red (CR) removal from aqueous solution in comparison with natural kaolin (K). The effect of various experimental parameters was investigated using a batch adsorption technique. In this manner, the adsorption isotherms and adsorption kinetics of CR on K and KC were examined. The isothermal data could be well described by the Langmuir equation and the dynamical data fit well with the pseudo-second-order kinetic model. The adsorption capacity of modified kaolin KC (24.46 mg/g) was found to be around 4 times higher than that of natural kaolin K (5.94 mg/g). The KC demonstrated the highest adsorption capacity by removing over 98% of CR after ten minutes of contact. These results indicate that CTAB-kaolin could be employed as low-cost alternative to activated carbon in wastewater treatment for the removal of colour which comes from industrial effluents of textile activities, tanning or printing.