The need for energy for the purpose of thermal comfort in buildings is constantly growing. To minimize this need, we can improve the performance of the building envelope, which is the seat of several thermal stresses, which encourages us to develop, apart from renewable or alternative energies, construction materials for buildings capable of storing energy. For this, the integration of innovative passive materials in the building envelope makes it possible to reduce energy consumption and ensure thermal comfort in countries with a very hot climate such as the desert zone of Chad. We were thus interested in the characterization of diatomite which is used to build a good majority of dwellings in the Lake Chad, Kanem and BET regions. To this end, samples of diatomite used in the construction were taken from Faya, the capital of the far north of Chad, on which we carried out mineralogical analyzes as well as thermal and mechanical characterization. Observations at the SEM, analyzes by fluorescence of rays X and Diffractograms clearly confirm pure diatomite. Furthermore, the results of the various thermo-physical and mechanical tests presented a material which has a low mechanical resistance but a good thermal resistance. Therefore, the diatomite which has been the subject of this study has no negative effect on the environment, it is an excellent thermal insulation material capable of storing thermal energy in buildings.

This research work concerns the physical characterizations and the measurement of the thermal conductivities of clay materials stabilized by a mixed binder. At first, the different physical characterizations are carried out for the classification of the study material. Then, cylindrical specimens 7 cm in diameter by 7 cm in height are made with clay alone, specimens stabilized with 5% Gum Arabic, specimens stabilized with 5% cement, and also specimens stabilized with 5% cement and 5% Gum Arabic and finally specimens stabilized with the various binders mentioned above and reinforced with rice straw at a rate of 1%. The results show that the thermal conductivity value of 0.73 W/mK is for the 100% A formulation, the small thermal conductivity values ​​are obtained for the formulations 94%A+5%GA+1%P and 94%A+5%C+1%P. which are respectively 0.60 W/mK and 0.59 W/mK and finally, the high value of the thermal conductivity is 0.90 W/mK for the formulation 90% A+5% GA+5% C.

Particles generated by wood machining have a proven impact on the health of users and woodworkers. The aim of this study was to quantify and describe wood particles in solid and gas phases to reliably and reproducibly characterise these emissions. First, we developed an experimental device that produced particles from solid wood and wood-based panels using portable machine tools. The objective was to study the particles emitted by wood machining while avoiding ambient pollution. Based on own technical specifications, the experimental system was defined and composed of various elements that integrated treatment of inlet air through wood machining to the analysis section that allows solid and gas phases. The first experiments were carried out in sanding and sawing modes on materials used in construction, including solid wood (spruce) and composite panels (particle board (PB), oriented strand board (OSB), and medium density fibreboard (MDF)). Wood-based panels showed more emissive behaviour than solid wood, both for the solid phase and the gas phase. These tests validate the feasibility of generating and measuring particles and emissions of volatile organic compounds (VOCs). Further modifications to the experimental device would enable us to integrate additional devices, such as toxicological ones, to better understand the impact of these wood particles on the health of woodworkers.

Energy production from fossil fuels is a conventional method which has negative impacts on environment and puts a heavy burden on economy of a country. The developed countries are focusing more on renewable energy sources and reducing their dependency on fossil fuels. Among other renewable sources of energy, biomass is a reasonable source of energy because it also solves the problem of disposal of waste products. Fast pyrolysis is a high temperature thermochemical conversion process widely used for production of bio oil from biomass. Pyrolysis model of olive mill waste water sludge is developed in Aspen Plus based upon the experimental results. Pyrolysis of olive mill waste water takes place at 450°C in a fluidized bed reactor. The products are passed through cyclone at 350^°C for removal of biochar. Bio oil vapors and non-condensable gases are passed through a series of condensers. A heat exchanger carrying water is employed after cyclone to condense the bio oil vapors at 90°C. Cooling water is heated upto 67°C in the heat exchanger which is a suitable temperature to drive an adsorption machine. This adsorption machine is used to condense water vapors at 10°C. The exergy analysis of the process shows that a net heat transfer of 30 W takes place in the first condenser. Overall exergy efficiency of pyrolysis olive mill waste water sludge is about 83% taking into account all products. High efficiency suggests that pyrolysis is a very efficient process for production of bio-oils.

The objective of this study is to evaluate the influence of wood ashes on the mechanical and thermal characteristics of the clayey earth-ashes compound (CEAC) compressed blocks. Variable mass percentages of 0% to 60% of wood ashes were incorporated to clayey earth stabilized with 10% of cement. The physical characteristics of the clayey earth were determined according to the protocols of the french association of normalization. The manufactured blocks were subjected to mechanical tests: simple compression and tensile by bending. The thermal conductivity was then appreciated by the method of the hot strip. The blocks made with a mixture of “90% clayey earth” and “10% cement”, usually used in construction in Benin, served as a reference material. From the results obtained, it appears that the clayey earth used is a soil A2ts: fine clayed sand in a very dry state. The results of the mechanical and thermal tests show that for an addition of wood ashes between 10% and 20% by weight, the performances of the blocks are significantly improved. The CEAC blocks formulated from 80% of the mixture “90% of clayey earth and 10% of cement” and 20% of wood ashes can be used as building materials.

The work we present is a comparative study based on an experimental approach to the mechanical and thermal properties of different local clay-based building materials with the incorporation of agricultural waste in Chad. These local building materials have been used since ancient times by the low-income population. They were the subject of a detailed characterization of their mechanical and thermal parameters. The objective is to obtain lightweight materials with good thermomechanical performance and which can contribute to improving thermal comfort, energy-saving, and security in social housing in Chad while reducing the cost of investment. Several clay-based samples with increasing incorporation of 0 to 8% of agricultural waste (cow dung or millet pod) were made. We used appropriate experimental methods for porous materials (the hydraulic press for mechanical tests and the box method for thermal tests). In this article, we have highlighted the values and variations of the mechanical compressive resistances, thermal conductivities, and thermal resistances of test pieces made with these materials. Knowing the mechanical and thermal characteristics, we also carried out a thermomechanical study. The thermal data made it possible to make Dynamic Thermal Simulations (STD) of the buildings thanks to the Pléiades + COMFIE software. The results obtained show that the use of these materials in a building presents good mechanical and thermal performance with low consumption of electrical energy for better thermal comfort of the occupants. Thus agricultural waste can be recovered thanks to its integration into building materials based on clay.

This study aims to determine the physical characteristics of rice straw and highlights the presence of sugar in rice straw. The use of natural fibers as a reinforcement in construction has existed for millennia. They are mixed with clay to make building materials. This addition avoids cracks and sometimes contributes to flexural strength. Researchers have detected a high level of sugar in natural fibers. This sugar contained in the biomass is at the origin of the setting delay and the hardening of the building materials. Another not least significant defect found in natural fiber is its high water absorption potential. This hydrophilic character is due to the intrinsic porosity of the straws. This article aims to determine the physical characteristics of rice straw and highlights the presence of sugar in rice straw. First, the density and water absorption rate of the rice straw were determined. Then chemical tests were carried out to determine the rate of mineral constituents (ash), lignin, hemicellulose and finally the rate of cellulose is deduced. Like most crop straws, rice straw contains a high level of sugar. It also has a very low density compared to other building materials. It is around 450 kg/m3. Rice straw also has a high water absorption rate. The absorption rate absorption rate (At) 5 min of immersion in water, its absorption rate reaches 234%.

The activated carbons were prepared from Phoenix dactylifera rachis (PRAC) and Ziziphus jujuba stones (JSAC) using chemical activation by H3PO4. Then, they applied to eliminate a commercial reactive dye BEZAKTIV Red S-Max (BRSM). The resultant carbons PRAC and JSAC were characterized by N-2 adsorption-desorption isotherms, Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA), thermo gravimetric analysis (TGA), scanning electron microscopy (SEM) and Boehm titration method. The BET apparent surface area of the PRAC and JSAC was 1283 and 1896 m(2)/g, respectively, with predominance acidic character. The effects of initial dye concentration and contact time, pH and temperature on the adsorption were investigated, and it was showed that the elimination percentage decreases as the initial concentration increases, but it rose with the temperature. The experimental equilibrium data were studied using Langmuir, Freundlich and Temkin models, and it was found that the Langmuir model described well the BRSM adsorption (R-2 >= 0.96), showing a maximum adsorption capacity of BRSM onto PRAC and JSAC of 196.08 and 37.04 mg/g, respectively. The BRSM adsorption kinetic was examined by pseudo-first-order, pseudo-second-order, elovich and intraparticle diffusion models, and it was showed that BRSM adsorption onto used carbons followed pseudo-second-order. The obtained thermodynamic parameters indicated that the phenomenon is spontaneous and endothermic. In addition, the thermal regeneration of the examined carbons revealed that they can be reused on adsorption test. Finally, the results indicated that the Phoenix dactylifera rachis carbon could be considered as low cost material for the elimination of BRSM dye and dyes from dyestuff wastewater (DW).

In aqueous solutions, hexavalent chromium Cr(VI) was successfully removed by activated carbon “ Z. jujuba rubidium carbonate-activated carbon” obtained from waste lignocellulosic material ( Ziziphus jujuba cores). Rubidium carbonate was used to prepare Z. jujuba rubidium carbonate-activated carbon by chemical activation using a 1:1 w/w ratio. Our results indicate that the obtained surface area of the activated carbon was equal to 608.31 m2/g. The adsorption study of Cr(VI) was investigated under batch conditions at constant stirring speed (220 r/min). Factors such as pH (1–6), temperature (20–40°C), adsorbent concentration (0.5–3 g/l), and initial Cr(VI) concentration (50–500 mg/l) were all studied to attain the maximum removal efficiency. Prior to the adsorption process, the morphology, elementary composition, and loss mass of activated carbon were characterized using scanning electron microscopy, X-ray fluorescence spectrometry, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Fourier transform infrared analysis of the adsorbent demonstrated the presence of key functional groups associated with the adsorption phenomenon such as those of hydroxyl and aromatic groups. The obtained results showed that the optimal conditions for a maximum adsorption efficiency are 2 for pH, 1 g/l for activated carbon dosage and 100 mg/l for Cr(VI) concentration. The removal percentage increased from 27.2 to 62.08%. The kinetic sorption was described by a pseudo-second-order kinetic equation ( R2 ≈ 0.995). The Tóth ( R2 = 0.997) and Elovich models were best to explain the sorption phenomenon. Thermodynamic studies showed that the adsorption of Cr(VI) onto activated carbon was feasible, spontaneous, and endothermic at 20–40°C. This novel Z. jujuba rubidium carbonate-activated carbon derived from Z. jujuba core has been found to be effective for the removal of Cr(VI) and not harmful to the ecosystem.

20Nov 2017 EFFECT OF THE ADDITION OF GLASS BOTTLE PARTICLES ON THE MECHANICAL STRENGTHS OF COMPRESSED BLOCKS OF FIRED CLAY AND STABILIZED EARTH. Gbenonde S. G. MILOHIN , Malahimi ANJORIN , Victor S. GBAGUIDI , S. Constant ADISSIN , Andre DONNOT and Riad BENELMIR. Laboratory of Applied Energetics and Mechanics (LEMA), Polytechnic School of Abomey-Calavi / University of Abomey-Calavi, 01 BP. 2009 Cotonou (Benin). Laboratory of Testing and Research on Wood Material (LERMAB), Faculty of Science & Technology / University of Lorraine ?Bd. des Aiguillettes B.P. 70239 F-54506 Vandoeuvre-l?s-Nancy cedex, France.

In this study, activated carbons were prepared from date palm rachis (RPK) and jujube stones (NJK), by-product agricultural wastes which have been tested for the elimination of reactive dye BEZAKTIV Red S-MAX (BRSM) from aqueous solutions by batch adsorption method. Both activated carbons were prepared using chemical activation by KOH as an impregnating agent (rate of KOH/biomass (w/w) of 0.74) at 800°C in the presence of inert gas (N2). RPK and NJK were characterized using BET, SEM, FTIR and Boehm titration mass. The results show that RPK possess the higher specific surface area (1160m2/g). The effect of contact time, solution temperature and solution pH on the adsorption of BRSM dye were also studied. The experimental data were analysed using Langmuir, Freundlich and Temkin isotherm models. The equilibrium data fitted well with the Langmuir isotherm model, and the adsorption capacities were calculated to be 128.21 and 28.49mg/g using RPK and NJK, respectively. The kinetic data were fitted to pseudo-first order, pseudo-second order, elovich and intra-particle diffusion model. Thermodynamic parameters such as ∆G°, ∆H° and ∆S° were also estimated for the adsorption study and they were found to be spontaneous and endothermic processes. Desorption and regeneration study was made to test the viability of reusing the adsorbents. Lastly, it was found that RPK is efficient in dyes removal from real wastewater.

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.

In this study, microcrystalline cellulose (Alfa-MCC) was extracted from Alfa fibres using acid hydrolysis method. The molecular weight of the cellulose samples was determined by gel permeation chromatography. The crystallinities were studied by means of X-ray diffraction and solid state cross polarization magic angle spinning (13)C nuclear magnetic resonance spectroscopy, revealing that Alfa-MCC was more crystalline than the native cellulose isolated from Alfa fibres. The morphology of the celluloses was investigated using scanning electron microscopy, showing a compact structure and a rough surface. Furthermore, a good thermal stability was shown for Alfa-MCC. Based on these analyses, Alfa-MCC showed tremendous potential use as composites reinforcing agent, foods stabilizer and pharmaceutical additive.

The enhancement of wood waste is a promising solution for the production of energy from renewable resources. Nevertheless, wood waste often needs a preliminary treatment step to remove pollutants present in the material. The thermal cleaning of wood laminated flooring (WLF) waste is studied through thermogravimetric and FTIR analyses. As a first step, it has been shown, through non iso-thermal tests, that degradation temperature ranges for wood and additives (aminoplast resins) are different, making it possible to proceed to a thermal cleaning through a low temperature pyrolysis. It has also been highlighted that chemical linkages between the different components of WLF waste influence their own thermal behaviour making it difficult to predict the thermal behaviour of the whole material. Fourier transform infra-red spectrometry analyses reveal that NH 3 and HNCO are the main nitrogen-containing gases produced during pyrolysis, which highlights the pyrolysis efficiency in terms of nitrogen (i.e., resin) removing. Lastly, thermal degradation of wood and WLF has been modelled to provide information for reactor designing.

Many cereal straws have been used as raw materials for the preparation of microcrystalline cellulose (MCC). These raw materials were gradually replaced with wood products; nevertheless about 10% of the world overall pulp production is obtained from non-wood raw material. The main interest in pulp made from straw is that it provides excellent fibres for different industries with special properties, and that it is the major available source of fibrous raw material in some geographical areas.The aim of the present work was to characterize microcrystalline cellulose prepared from alfa fibers using the hydrolysis process. The products obtained are characterized with FTIR spectroscopy and X-ray powder diffraction.As a result, FTIR spectroscopy is an appropriate technique for studying changes occurred by any chemical treatment. The spectrum of alfa grass stems shows the presence of lignin and hemicelluloses. However, the cellulose spectrum indicates that the extraction of lignin and hemicellulose was effective. The X-ray analysis indicates that the microcrystalline cellulose is more crystalline than the source material.

Alfa fibres are extracted from the plant Stippa tenacissima, or esparto grass (alfa is the Arab name for esparto), and grows in the dry regions of North Africa. It belongs to the graminacies family and grows to a height of about 1 m. These fibres are mostly used in the production of paper. Recently, they have been used as reinforcement in the production of biodegradable composites. The aim of the present work was to prepare microcrystalline cellulose from esparto grass using the hydrolysis process. The products obtained are characterized with thermogravimetric analysis. As a result, the thermal decomposing patterns of the cellulosic preparations, obtained by hydrochloric hydrolysis gave additional evidence to the relatively higher stability of the more crystalline cellulosic preparations. In the main decomposition stage, the cleavage of the glycosidic linkages of cellulose reduces the polymerization degree leading to the formation of CO2, H2O and other hydrocarbon derivatives.

Wood extractives are considered commonly of major importance for the wood toxicity. Probably the first step of illness is the penetration of toxic molecules into human corpus, so we examine and compare extractives coming from woods commonly in Morocco industry. We solvate extractives from direct wood powder in water, sodium chloride solution and ringer salt solution. Dry powder of extractives woods are then characterize by IR spectra. We found great correlation between group of IR peaks that limit the independent peaks at five, each of them being characteristics of one or more chemical bonds. Comparing the peaks intensity between the free solvent show a selectivity effect of salts against the chemical bonds present into the extracts.

AbstractThis work is a modelling of the Aireco® filtration system. This heat exchanger, with particle catching capabilities, is made of a cyclonic body which contains refrigerated coils. The water vapour contained in the gas to be treated condensed on the coils surface. Our modelling considers two main capture surfaces: the entry zone in which particles are collected by inertial impaction and the cyclonic body in which particles diffused by centrifugal force is the main phenomena. We found that these considerations explain our experimental results with an accuracy more than 90%, when the Aireco® is on a normal point of working.