Sabrine Alila - Academia.edu (original) (raw)

Papers by Sabrine Alila

The use of biomass as an effective adsorbent follows meadow treatments and chemical treatments is... more The use of biomass as an effective adsorbent follows meadow treatments and chemical treatments is profitable because of the low cost, high abundance, easy availability and high adsorption capacity. The vegetable sponge (Luffacylindrica) is one of the biomass renewable. The Luffa sponge is a rigid porous material, has been characterized by FTIR and NMR and used as an adsorbent for the removal of heavy metals from aqueous solutions. It showed an efficient adsorption, exceeding 96% toward Pb 2+ , Cd 2+ , Zn 2+ , Cu 2+ , Hg 2+ and Ni 2+ when their concentration was lower than 10 ppm and ranged from 90% to 60% for a metal concentration higher than10 ppm. Over 98% of the adsorbed metal ion was recovered using EDTA as a desorbing solution, and the subsequent washing allowed the luffa sponge to be reused repeatedly without noticeable loss of adsorption capacity. It was concluded that the Luffa sponge oxidized may be used as a high capacity and reusable sorbent material in heavy-metal removing processes.

International Journal of Masonry Research and Innovation, 2019

The effect of wood fibre flour in a studied Portland cement material shows interesting mechanical... more The effect of wood fibre flour in a studied Portland cement material shows interesting mechanical properties. The objective of this work is the elaboration new composite materials by emulsion. The dispersion of wood fibre and compressive strength was studied. The results showed an improvement in compressive strength of over 40% with 2% added wood fibres flour. The chemical modification of the wood fibres into their surfaces changes from the hydrophilic state to the hydrophobic state which makes it necessary to reduce the amount of water absorbed by the sample. The addition of anionic surfactant in the mixing water further improves the surface of the samples by minimising the pore size, hence the reduced water absorption. The dispersion of the wood fibres is controlled and assumed by an anionic surfactant as an emulsion phenomenon, the elaborate Maserati has thermal properties can be used as phase change materials (PCMs).

Journal of Renewable Materials, 2019

The influence of nanofiberwood on the properties of the fresh condition of cement based mortars i... more The influence of nanofiberwood on the properties of the fresh condition of cement based mortars is not known in detail, despite recent advances in nanocellulose technology and it is related composite materials. Nanofiber wood from industrial waste, produced by high-pressure homogenization, was used as cement partial replacement for cement paste at a content ranging from 0% to 2% by weight of cement. The effect of the nanofiber wood content on the porosity, the compressive strength and the degree of hydration of the cement was investigated. Results have shown an improvement in the compressive strength by more than 50% with 1% of added fiber wood. The chemical modification of nanofibers wood by grafting of chains alkyls in their surfaces can reduce the quantity of water absorbed by the sample. The addition of an anionic additive (SDBS) in the water of mixing improves of more the surface of samples by minimizing the size of pores by emulsion effect, from where the absorption of water reduces. The degree of hydration of the cement has increased with the cellulose content containing nanofibrils. The analyze revealed that the presence of nanofiber wood favored the hydration of the cement by producing more calcium silicate gel and portlandite, probably the main reason for this improvement in compressive strength.

Journal of Renewable Materials, 2019

Nanofibrillated wood fiber was used as fillers in the partial cement matrix replacing the cement ... more Nanofibrillated wood fiber was used as fillers in the partial cement matrix replacing the cement to a content of up to 2% by weight of cement. The nanofibrillated effect of wood fibers on porosity, thermal properties and compressive strength was studied. The results obtained showed an improvement in compressive strength of more than 40% with 1% by weight of wood fiber nanofibrillate. The addition of nanofibrillated wood fiber shows a good pore reduction, and the best result was obtained with emulsion of a mixture incorporating 1% by weight of wood fiber nanofibrillate in the presence of an anionic surfactant (SDBS). Thermal conductivity measurements and thermal expansion coefficient, compared to nanofibrillated wood fiber reinforced cement pastes, showed the reinforcing efficiency of cellulose fiber nanofibrillate. The degree of hydration of the cement increased with nanofibrillated wood fibers. This property has been confirmed by Fourier transform infrared spectroscopy. These analyzes revealed that the presence of nanofibrillated wood fibers generates and promotes the hydration of the cement, producing more portlandite and calcium silicate gel, which influences the compressive strength which gives a strong improvement.

Biomedical and Environmental Applications, 2011

... The adsorbed pesticide may be stripped off by sonication with methanol, making the regenerati... more ... The adsorbed pesticide may be stripped off by sonication with methanol, making the regeneration and reuse of sorbents possible. In a study achieved by Memon et al. ... (1994) Garcia DB . et al. (2008) Achak a et al. (2009) Mubeen a A . et al. (2006) Mubeen a A . et al. (2007) ...

Langmuir, 2007

In this work, the adsorption of cationic surfactant and organic solutes on oxidized cellulose fib... more In this work, the adsorption of cationic surfactant and organic solutes on oxidized cellulose fibers bearing different amounts of carboxylic moieties was investigated. The increase in the amount of-COOH groups on cellulose fibers by TEMPO oxidation induced a general rise in surfactant adsorption. For all tested conditions, that is, cellulose oxidation level and surfactant alkyl chain length (C12 and C16), adsorption isotherms displayed a typical three-region shape with inversion of the substrate-potential which was interpreted as reflecting surfactant adsorption and aggregation (admicelles and hemimicelles) on cellulose fibers. The addition of organic solutes in surfactant/cellulose systems induced a decrease in surfactant cac on the cellulose surface thus favoring surfactant aggregation and the formation of mixed surfactant/solute assemblies. Adsorption isotherms of organic solutes on cellulose in surfactant/cellulose/ solute systems showed that solute adsorption is strictly correlated to (i) the surfactant concentration, solute adsorption increases up to the surfactant cmc, where solute partitioning between the cellulose surface and free micelles causes a drop in adsorption, and to (ii) solute solubility and functional groups. The specific shape of solutes adsorption isotherms at a fixed surfactant concentration was interpreted using a Frumkin adsorption isotherm, thus suggesting that solute uptake on cellulose fibers is a coadsorption and not a partitioning process. Results presented in this study were compared with those obtained in a previous work investigating solute adsorption in anionic surfactant/cationized cellulose systems to better understand the role of surfactant/solute interactions in the coadsorption process.

Langmuir, 2005

This paper reports on a flowable lignocellulosic thermoplastic prepared from forestry biomass by ... more This paper reports on a flowable lignocellulosic thermoplastic prepared from forestry biomass by solvent-free acetylation. The non-solvent approach relies upon a functionalizing agent derived from benzethonium chloride (hyamine) and sulfuric acid, which was chosen for its similar wetting attributes to an ionic liquid for the lignocellulose but was much less inexpensive to use. Besides acetylation, this functionalizing agent became chemically bonded to the lignocellulose by the sulfate group formed in situ, as demonstrated by 13 C NMR, infrared and elemental analysis. This attached species appeared to contribute strongly to the flowable nature of the product. The modified material showed good melt flowability by compression molding, as demonstrated in this study by the production of semi-transparent films and was characterized by differential scanning calorimetry and dynamic mechanical analysis. An experimental investigation of reaction parameters was included in the study, exploring the mechanism by which the cationic functionalizing agent modified the structure of lignocellulose.

International Journal of Environmental Technology and Management, 2010

Chemically modified cellulose fibres were used as adsorbents for the removal of organic compounds... more Chemically modified cellulose fibres were used as adsorbents for the removal of organic compounds and herbicides from water. The chemical modification of fibres by grafting hydrocarbon moieties enhances the adsorption capacity of cellulose substrate. The adsorption behaviour of the modified fibres towards various organic solutes and three herbicides was investigated. The viability of application of the modified cellulose fibres for the removal organic pollutant in continuous mode was confirmed by using column

Industrial Crops and Products, 2011

Chemically modified starch nanocrystals were used as adsorbents for the removal of aromatic organ... more Chemically modified starch nanocrystals were used as adsorbents for the removal of aromatic organic compounds from water. The nanocrystals were chemically modified by grafting with stearate moieties which enhanced the adsorption capacity of the nanometric substrate. Their adsorption capacity ranged between 150 and 900 mol g −1 of modified nanoparticles and the adsorption isotherms could be described accurately by the Langmuir model. The adsorption kinetics followed a two-step process with first pure adsorption of the aromatic compounds onto the surface of the nanoparticles followed by a diffusion of the compounds into the layer of surface chains grafted onto the nanoparticles. Furthermore, the feasibility of using these nanoparticles in continuous flow mode processes was confirmed using a fixed bed column setup. The fixed bed column could also be regenerated by washing with ethanol and was found not to exhibit any loss in adsorption capacity over multiples adsorption-desorption cycles.

Industrial Crops and Products, 2009

Different modified cellulose fibers were prepared and their efficiency as adsorbent for the remov... more Different modified cellulose fibers were prepared and their efficiency as adsorbent for the removal of several aromatic organic compounds and three herbicides, i.e.; Alachlor (ACH), Linuron (LNR) and Atrazine (ATR), was investigated. The evolution of the adsorption capacity according to the solute structure and the modification sequence was explored. The modification was carried on under heterogeneous conditions using N,N-carbonyldiimidazole (CDI) as an activator and different amino derivatives as grafting agent. By varying the structure of the amino derivative and the reaction sequence, different organic structures bearing diverse functional groups were generated on the surface. Evidence for the occurrence of the surface modification was confirmed by FTIR, XPS and solid-state 13 C NMR spectroscopy. It was shown that the chemical modification of the fibers' surface greatly enhanced the adsorption capacity toward organic compound dissolved in water. The adsorption capacity evolved from 20 to 50 mol g −1 for the virgin fibers to between 400 and 1000 mol g −1 for the modified substrates, depending on the solute structure and the modification sequence. The efficiency of the retention property under a continuous regime was also confirmed by using a column filled with the modified fibres. Once exhausted, the column could be reused by washing its contents with ethanol, which totally extracted the trapped compounds. The regenerated column was then used in several adsorption-desorption cycles without any loss of the capacity.

Industrial Crops and Products, 2013

The extraction of microfibrillated cellulose (MFC) from fibres of several non-woody plants (basts... more The extraction of microfibrillated cellulose (MFC) from fibres of several non-woody plants (basts of flax, hemp, jute, leaves of sisal and abaca) has been explored. MFC was isolated using high pressure homogenization process at a pressure lower than 600 bar. Fibres extracted from the plants by alkaline pulping process were first bleached and submitted to TEMPO-mediated oxidation to facilitate the fibrillation process. Evidence of the successful isolation of nanofibrils was given by FE-SEM observation revealing fibrils with a width in the 20 up to 50 nm range, depending on the fibres origin. Particular attention was paid to characterize the ensuing MFC using different physical methods (DP, transparency degree, DRX) to enable a comparative analysis of the nanofibrils properties, and evaluate the ease of fibrillation. From this investigation, it seems that the fibres with the highest content in hemicelluloses led to the highest yield in MFC.

Industrial Crops and Products, 2013

Highly porous cellulose organogels were prepared from nanofibrillated cellulose hydrogels and the... more Highly porous cellulose organogels were prepared from nanofibrillated cellulose hydrogels and their adsorption properties towards a wide range of organic pollutants were investigated. Here, we show that by functionalizing the native cellulose nanofibrils of the organogel with the hydrophobic hydrocarbon chains, the adsorption capacity is meaningfully boosted, making possible to use the modified organogel as an adsorbent for organic compounds. The chemical modification was confirmed by infrared spectroscopy (FTIR) and solid NMR spectroscopy. The kinetics and adsorption isotherms of several aromatic compounds, including herbicides were investigated. It was proposed that the adsorption process is the result of the diffusion of the organic solute inside the grafted hydrocarbon chains acting as a reservoir on which the organic compounds would be accumulated. The results showed that the modified cellulose organogels could be easily regenerated and reused without any loss of the adsorption capacity, which constitutes one of the main advantages of this category of the adsorbents derived from a renewable resource.

Cellulose, 2013

The effect of the hemicellulose content and that of the fibre morphology on the nanofibrillation ... more The effect of the hemicellulose content and that of the fibre morphology on the nanofibrillation behaviour of delignified cellulose pulps were studied. For this purpose, pulps from two non-woody plants, alfa (Stipa tenacissima) and sunflower (Helianthus annuus), were delignified using NaClO 2 / acetic acid and the NaOH pulping processes to obtain fibres with different hemicellulose contents. The ensuing fibres were characterized by chemical analysis, SEM, FTIRS and X-ray diffraction. The fibres were then disintegrated into nanofibrillated cellulose (NFC) using either a high pressure homogenizer or a domestic blender. The degree of fibrillation and the morphology of the nanofibrillated fractions were evaluated by centrifugation and Field-emission scanning electron microscopy. Pulps containing the highest hemicellulose content showed higher yields of the nanofibrillated fraction and a better aptitude for the individualization of the microfibrils. Furthermore, it was shown that fibres from sunflowers exhibiting a thinner cell wall were easier to fibrillate and could be disintegrated into NFC by just using a simple domestic-blender once deliginification process was carried out using the NaClO 2 /acetic acid method. Eucalyptus fibres were also used to further confirm the key role of hemicelluloses in the nanofibrillation process of woody plants.

Cellulose, 2006

Polypyrrole was polymerized on the surface of cellulose fibres using a sequence of fibre impregna... more Polypyrrole was polymerized on the surface of cellulose fibres using a sequence of fibre impregnation in FeCl 3 solutions, thickening and re-dispersion in a pyrrole solution. f-Potential and adsorption isotherms of the FeCl 3-cellulose systems showed that the adsorption of iron III was associated with the formation of free Fe 3+ cations in the impregnation liquor. Moreover, under the test conditions applied, the amount of adsorbed iron III was not sufficient to promote the polymerization of a adequate amount of pyrrole on the fibre surface. Optimization of the polymerization reaction required that the FeCl 3 concentration in the impregnation liquor be increased to approximately 1 mol/l with a subsequent decrease of pH to approx-imately1.8. Based on scanning electron (SEM) micrographs and the low cellulose polymerization degree measured after pyrrole polymerization, we concluded that the decrease in the electric resistance of bulky polypyrrole/cellulose compounds was associated with a not negligible degradation of the cellulose fibres due to acid hydrolysis and the subsequent impossibility to prepare hand sheets with modified fibres due to the insufficient strength of the wet fibre network. The results of this investigation bring into question the use of FeCl 3-pyrrole-cellulose systems for the elaboration of conducting paper sheets with good and stable mechanical properties.

Carbohydrate Polymers, 2009

Surface grafting of different amino derivatives was carried on under mild condition using N,N 0-c... more Surface grafting of different amino derivatives was carried on under mild condition using N,N 0-carbonyldiimidazole (CDI) as an activator. The action of a diamine or a triamine on previously activated cellulose fibres proceeds by the reaction of one amine function giving rise to a carbamate derivative. The other terminal amino groups remained available for further reaction. In particular, their activation with CDI generates a reactive carboxamide able to condense with an aliphatic amine through a urea linkage. Evidence for the occurrence of the reaction at each modification step was confirmed by Fourier Transform Infrared Spectroscopy (FTIRS) and X-ray photoelectron spectroscopy (XPS). The contact angle measurement, using water as a probe, was used to explore the evolution of the surface wettability for the different modification sequences. It was shown that the contact angle value is determined by the ratio between polar and methylene groups and by the spatial arrangement of the molecule on the surface.

Carbohydrate Polymers, 2011

In the present work the effect of the carboxyl content on the high pressure defibrillation of oxi... more In the present work the effect of the carboxyl content on the high pressure defibrillation of oxidized eucalyptus from micro to nanoscale size was investigated. It has been shown that TEMPO-mediated oxidation of dried softwood pulp not only facilitates the defibrillation process, but also reduces the number of passes necessary to get the gel, as well as preventing the clogging of the homogenizer. In fact, these effects became apparent up to a carboxyl content about 300μmol/g, and over 500μmol/g, the yield in the nanofibrillated cellulose exceeded 90%, at a defibrillation pressure of 600bar. The morphology of the ensuing nanofibrillated cellulose (NFC) and its crystalline degree were characterised by FE-SEM and DRX measurement, respectively. The evolution of the transparency degree and the viscosity according to the oxidation degree and defibrillation pressure were also analysed by UV–vis transmittance and rheological measurement.The reinforcing potential of the ensuing NFC was explored by means of dynamic mechanical analysis (DMA) carried on nanocomposite film prepared from a suspension of NFC as the reinforcing phase and an acrylic latex dispersion as the matrix.

Modified biopolymer adsorbent for the removal of dissolved organic pollutants

Industrial Crops and Products, 2011

Chemically modified starch nanocrystals were used as adsorbents for the removal of aromatic organ... more Chemically modified starch nanocrystals were used as adsorbents for the removal of aromatic organic compounds from water. The nanocrystals were chemically modified by grafting with stearate moieties which enhanced the adsorption capacity of the nanometric substrate. Their adsorption capacity ranged between 150 and 900 mol g −1 of modified nanoparticles and the adsorption isotherms could be described accurately by the Langmuir model. The adsorption kinetics followed a two-step process with first pure adsorption of the aromatic compounds onto the surface of the nanoparticles followed by a diffusion of the compounds into the layer of surface chains grafted onto the nanoparticles. Furthermore, the feasibility of using these nanoparticles in continuous flow mode processes was confirmed using a fixed bed column setup. The fixed bed column could also be regenerated by washing with ethanol and was found not to exhibit any loss in adsorption capacity over multiples adsorption-desorption cycles.

The use of biomass as an effective adsorbent follows meadow treatments and chemical treatments is... more The use of biomass as an effective adsorbent follows meadow treatments and chemical treatments is profitable because of the low cost, high abundance, easy availability and high adsorption capacity. The vegetable sponge (Luffacylindrica) is one of the biomass renewable. The Luffa sponge is a rigid porous material, has been characterized by FTIR and NMR and used as an adsorbent for the removal of heavy metals from aqueous solutions. It showed an efficient adsorption, exceeding 96% toward Pb 2+ , Cd 2+ , Zn 2+ , Cu 2+ , Hg 2+ and Ni 2+ when their concentration was lower than 10 ppm and ranged from 90% to 60% for a metal concentration higher than10 ppm. Over 98% of the adsorbed metal ion was recovered using EDTA as a desorbing solution, and the subsequent washing allowed the luffa sponge to be reused repeatedly without noticeable loss of adsorption capacity. It was concluded that the Luffa sponge oxidized may be used as a high capacity and reusable sorbent material in heavy-metal removing processes.

International Journal of Masonry Research and Innovation, 2019

The effect of wood fibre flour in a studied Portland cement material shows interesting mechanical... more The effect of wood fibre flour in a studied Portland cement material shows interesting mechanical properties. The objective of this work is the elaboration new composite materials by emulsion. The dispersion of wood fibre and compressive strength was studied. The results showed an improvement in compressive strength of over 40% with 2% added wood fibres flour. The chemical modification of the wood fibres into their surfaces changes from the hydrophilic state to the hydrophobic state which makes it necessary to reduce the amount of water absorbed by the sample. The addition of anionic surfactant in the mixing water further improves the surface of the samples by minimising the pore size, hence the reduced water absorption. The dispersion of the wood fibres is controlled and assumed by an anionic surfactant as an emulsion phenomenon, the elaborate Maserati has thermal properties can be used as phase change materials (PCMs).

Journal of Renewable Materials, 2019

The influence of nanofiberwood on the properties of the fresh condition of cement based mortars i... more The influence of nanofiberwood on the properties of the fresh condition of cement based mortars is not known in detail, despite recent advances in nanocellulose technology and it is related composite materials. Nanofiber wood from industrial waste, produced by high-pressure homogenization, was used as cement partial replacement for cement paste at a content ranging from 0% to 2% by weight of cement. The effect of the nanofiber wood content on the porosity, the compressive strength and the degree of hydration of the cement was investigated. Results have shown an improvement in the compressive strength by more than 50% with 1% of added fiber wood. The chemical modification of nanofibers wood by grafting of chains alkyls in their surfaces can reduce the quantity of water absorbed by the sample. The addition of an anionic additive (SDBS) in the water of mixing improves of more the surface of samples by minimizing the size of pores by emulsion effect, from where the absorption of water reduces. The degree of hydration of the cement has increased with the cellulose content containing nanofibrils. The analyze revealed that the presence of nanofiber wood favored the hydration of the cement by producing more calcium silicate gel and portlandite, probably the main reason for this improvement in compressive strength.

Journal of Renewable Materials, 2019

Nanofibrillated wood fiber was used as fillers in the partial cement matrix replacing the cement ... more Nanofibrillated wood fiber was used as fillers in the partial cement matrix replacing the cement to a content of up to 2% by weight of cement. The nanofibrillated effect of wood fibers on porosity, thermal properties and compressive strength was studied. The results obtained showed an improvement in compressive strength of more than 40% with 1% by weight of wood fiber nanofibrillate. The addition of nanofibrillated wood fiber shows a good pore reduction, and the best result was obtained with emulsion of a mixture incorporating 1% by weight of wood fiber nanofibrillate in the presence of an anionic surfactant (SDBS). Thermal conductivity measurements and thermal expansion coefficient, compared to nanofibrillated wood fiber reinforced cement pastes, showed the reinforcing efficiency of cellulose fiber nanofibrillate. The degree of hydration of the cement increased with nanofibrillated wood fibers. This property has been confirmed by Fourier transform infrared spectroscopy. These analyzes revealed that the presence of nanofibrillated wood fibers generates and promotes the hydration of the cement, producing more portlandite and calcium silicate gel, which influences the compressive strength which gives a strong improvement.

Biomedical and Environmental Applications, 2011

... The adsorbed pesticide may be stripped off by sonication with methanol, making the regenerati... more ... The adsorbed pesticide may be stripped off by sonication with methanol, making the regeneration and reuse of sorbents possible. In a study achieved by Memon et al. ... (1994) Garcia DB . et al. (2008) Achak a et al. (2009) Mubeen a A . et al. (2006) Mubeen a A . et al. (2007) ...

Langmuir, 2007

In this work, the adsorption of cationic surfactant and organic solutes on oxidized cellulose fib... more In this work, the adsorption of cationic surfactant and organic solutes on oxidized cellulose fibers bearing different amounts of carboxylic moieties was investigated. The increase in the amount of-COOH groups on cellulose fibers by TEMPO oxidation induced a general rise in surfactant adsorption. For all tested conditions, that is, cellulose oxidation level and surfactant alkyl chain length (C12 and C16), adsorption isotherms displayed a typical three-region shape with inversion of the substrate-potential which was interpreted as reflecting surfactant adsorption and aggregation (admicelles and hemimicelles) on cellulose fibers. The addition of organic solutes in surfactant/cellulose systems induced a decrease in surfactant cac on the cellulose surface thus favoring surfactant aggregation and the formation of mixed surfactant/solute assemblies. Adsorption isotherms of organic solutes on cellulose in surfactant/cellulose/ solute systems showed that solute adsorption is strictly correlated to (i) the surfactant concentration, solute adsorption increases up to the surfactant cmc, where solute partitioning between the cellulose surface and free micelles causes a drop in adsorption, and to (ii) solute solubility and functional groups. The specific shape of solutes adsorption isotherms at a fixed surfactant concentration was interpreted using a Frumkin adsorption isotherm, thus suggesting that solute uptake on cellulose fibers is a coadsorption and not a partitioning process. Results presented in this study were compared with those obtained in a previous work investigating solute adsorption in anionic surfactant/cationized cellulose systems to better understand the role of surfactant/solute interactions in the coadsorption process.

Langmuir, 2005

This paper reports on a flowable lignocellulosic thermoplastic prepared from forestry biomass by ... more This paper reports on a flowable lignocellulosic thermoplastic prepared from forestry biomass by solvent-free acetylation. The non-solvent approach relies upon a functionalizing agent derived from benzethonium chloride (hyamine) and sulfuric acid, which was chosen for its similar wetting attributes to an ionic liquid for the lignocellulose but was much less inexpensive to use. Besides acetylation, this functionalizing agent became chemically bonded to the lignocellulose by the sulfate group formed in situ, as demonstrated by 13 C NMR, infrared and elemental analysis. This attached species appeared to contribute strongly to the flowable nature of the product. The modified material showed good melt flowability by compression molding, as demonstrated in this study by the production of semi-transparent films and was characterized by differential scanning calorimetry and dynamic mechanical analysis. An experimental investigation of reaction parameters was included in the study, exploring the mechanism by which the cationic functionalizing agent modified the structure of lignocellulose.

International Journal of Environmental Technology and Management, 2010

Chemically modified cellulose fibres were used as adsorbents for the removal of organic compounds... more Chemically modified cellulose fibres were used as adsorbents for the removal of organic compounds and herbicides from water. The chemical modification of fibres by grafting hydrocarbon moieties enhances the adsorption capacity of cellulose substrate. The adsorption behaviour of the modified fibres towards various organic solutes and three herbicides was investigated. The viability of application of the modified cellulose fibres for the removal organic pollutant in continuous mode was confirmed by using column

Industrial Crops and Products, 2011

Chemically modified starch nanocrystals were used as adsorbents for the removal of aromatic organ... more Chemically modified starch nanocrystals were used as adsorbents for the removal of aromatic organic compounds from water. The nanocrystals were chemically modified by grafting with stearate moieties which enhanced the adsorption capacity of the nanometric substrate. Their adsorption capacity ranged between 150 and 900 mol g −1 of modified nanoparticles and the adsorption isotherms could be described accurately by the Langmuir model. The adsorption kinetics followed a two-step process with first pure adsorption of the aromatic compounds onto the surface of the nanoparticles followed by a diffusion of the compounds into the layer of surface chains grafted onto the nanoparticles. Furthermore, the feasibility of using these nanoparticles in continuous flow mode processes was confirmed using a fixed bed column setup. The fixed bed column could also be regenerated by washing with ethanol and was found not to exhibit any loss in adsorption capacity over multiples adsorption-desorption cycles.

Industrial Crops and Products, 2009

Different modified cellulose fibers were prepared and their efficiency as adsorbent for the remov... more Different modified cellulose fibers were prepared and their efficiency as adsorbent for the removal of several aromatic organic compounds and three herbicides, i.e.; Alachlor (ACH), Linuron (LNR) and Atrazine (ATR), was investigated. The evolution of the adsorption capacity according to the solute structure and the modification sequence was explored. The modification was carried on under heterogeneous conditions using N,N-carbonyldiimidazole (CDI) as an activator and different amino derivatives as grafting agent. By varying the structure of the amino derivative and the reaction sequence, different organic structures bearing diverse functional groups were generated on the surface. Evidence for the occurrence of the surface modification was confirmed by FTIR, XPS and solid-state 13 C NMR spectroscopy. It was shown that the chemical modification of the fibers' surface greatly enhanced the adsorption capacity toward organic compound dissolved in water. The adsorption capacity evolved from 20 to 50 mol g −1 for the virgin fibers to between 400 and 1000 mol g −1 for the modified substrates, depending on the solute structure and the modification sequence. The efficiency of the retention property under a continuous regime was also confirmed by using a column filled with the modified fibres. Once exhausted, the column could be reused by washing its contents with ethanol, which totally extracted the trapped compounds. The regenerated column was then used in several adsorption-desorption cycles without any loss of the capacity.

Industrial Crops and Products, 2013

The extraction of microfibrillated cellulose (MFC) from fibres of several non-woody plants (basts... more The extraction of microfibrillated cellulose (MFC) from fibres of several non-woody plants (basts of flax, hemp, jute, leaves of sisal and abaca) has been explored. MFC was isolated using high pressure homogenization process at a pressure lower than 600 bar. Fibres extracted from the plants by alkaline pulping process were first bleached and submitted to TEMPO-mediated oxidation to facilitate the fibrillation process. Evidence of the successful isolation of nanofibrils was given by FE-SEM observation revealing fibrils with a width in the 20 up to 50 nm range, depending on the fibres origin. Particular attention was paid to characterize the ensuing MFC using different physical methods (DP, transparency degree, DRX) to enable a comparative analysis of the nanofibrils properties, and evaluate the ease of fibrillation. From this investigation, it seems that the fibres with the highest content in hemicelluloses led to the highest yield in MFC.

Industrial Crops and Products, 2013

Highly porous cellulose organogels were prepared from nanofibrillated cellulose hydrogels and the... more Highly porous cellulose organogels were prepared from nanofibrillated cellulose hydrogels and their adsorption properties towards a wide range of organic pollutants were investigated. Here, we show that by functionalizing the native cellulose nanofibrils of the organogel with the hydrophobic hydrocarbon chains, the adsorption capacity is meaningfully boosted, making possible to use the modified organogel as an adsorbent for organic compounds. The chemical modification was confirmed by infrared spectroscopy (FTIR) and solid NMR spectroscopy. The kinetics and adsorption isotherms of several aromatic compounds, including herbicides were investigated. It was proposed that the adsorption process is the result of the diffusion of the organic solute inside the grafted hydrocarbon chains acting as a reservoir on which the organic compounds would be accumulated. The results showed that the modified cellulose organogels could be easily regenerated and reused without any loss of the adsorption capacity, which constitutes one of the main advantages of this category of the adsorbents derived from a renewable resource.

Cellulose, 2013

The effect of the hemicellulose content and that of the fibre morphology on the nanofibrillation ... more The effect of the hemicellulose content and that of the fibre morphology on the nanofibrillation behaviour of delignified cellulose pulps were studied. For this purpose, pulps from two non-woody plants, alfa (Stipa tenacissima) and sunflower (Helianthus annuus), were delignified using NaClO 2 / acetic acid and the NaOH pulping processes to obtain fibres with different hemicellulose contents. The ensuing fibres were characterized by chemical analysis, SEM, FTIRS and X-ray diffraction. The fibres were then disintegrated into nanofibrillated cellulose (NFC) using either a high pressure homogenizer or a domestic blender. The degree of fibrillation and the morphology of the nanofibrillated fractions were evaluated by centrifugation and Field-emission scanning electron microscopy. Pulps containing the highest hemicellulose content showed higher yields of the nanofibrillated fraction and a better aptitude for the individualization of the microfibrils. Furthermore, it was shown that fibres from sunflowers exhibiting a thinner cell wall were easier to fibrillate and could be disintegrated into NFC by just using a simple domestic-blender once deliginification process was carried out using the NaClO 2 /acetic acid method. Eucalyptus fibres were also used to further confirm the key role of hemicelluloses in the nanofibrillation process of woody plants.

Cellulose, 2006

Polypyrrole was polymerized on the surface of cellulose fibres using a sequence of fibre impregna... more Polypyrrole was polymerized on the surface of cellulose fibres using a sequence of fibre impregnation in FeCl 3 solutions, thickening and re-dispersion in a pyrrole solution. f-Potential and adsorption isotherms of the FeCl 3-cellulose systems showed that the adsorption of iron III was associated with the formation of free Fe 3+ cations in the impregnation liquor. Moreover, under the test conditions applied, the amount of adsorbed iron III was not sufficient to promote the polymerization of a adequate amount of pyrrole on the fibre surface. Optimization of the polymerization reaction required that the FeCl 3 concentration in the impregnation liquor be increased to approximately 1 mol/l with a subsequent decrease of pH to approx-imately1.8. Based on scanning electron (SEM) micrographs and the low cellulose polymerization degree measured after pyrrole polymerization, we concluded that the decrease in the electric resistance of bulky polypyrrole/cellulose compounds was associated with a not negligible degradation of the cellulose fibres due to acid hydrolysis and the subsequent impossibility to prepare hand sheets with modified fibres due to the insufficient strength of the wet fibre network. The results of this investigation bring into question the use of FeCl 3-pyrrole-cellulose systems for the elaboration of conducting paper sheets with good and stable mechanical properties.

Carbohydrate Polymers, 2009

Surface grafting of different amino derivatives was carried on under mild condition using N,N 0-c... more Surface grafting of different amino derivatives was carried on under mild condition using N,N 0-carbonyldiimidazole (CDI) as an activator. The action of a diamine or a triamine on previously activated cellulose fibres proceeds by the reaction of one amine function giving rise to a carbamate derivative. The other terminal amino groups remained available for further reaction. In particular, their activation with CDI generates a reactive carboxamide able to condense with an aliphatic amine through a urea linkage. Evidence for the occurrence of the reaction at each modification step was confirmed by Fourier Transform Infrared Spectroscopy (FTIRS) and X-ray photoelectron spectroscopy (XPS). The contact angle measurement, using water as a probe, was used to explore the evolution of the surface wettability for the different modification sequences. It was shown that the contact angle value is determined by the ratio between polar and methylene groups and by the spatial arrangement of the molecule on the surface.

Carbohydrate Polymers, 2011

In the present work the effect of the carboxyl content on the high pressure defibrillation of oxi... more In the present work the effect of the carboxyl content on the high pressure defibrillation of oxidized eucalyptus from micro to nanoscale size was investigated. It has been shown that TEMPO-mediated oxidation of dried softwood pulp not only facilitates the defibrillation process, but also reduces the number of passes necessary to get the gel, as well as preventing the clogging of the homogenizer. In fact, these effects became apparent up to a carboxyl content about 300μmol/g, and over 500μmol/g, the yield in the nanofibrillated cellulose exceeded 90%, at a defibrillation pressure of 600bar. The morphology of the ensuing nanofibrillated cellulose (NFC) and its crystalline degree were characterised by FE-SEM and DRX measurement, respectively. The evolution of the transparency degree and the viscosity according to the oxidation degree and defibrillation pressure were also analysed by UV–vis transmittance and rheological measurement.The reinforcing potential of the ensuing NFC was explored by means of dynamic mechanical analysis (DMA) carried on nanocomposite film prepared from a suspension of NFC as the reinforcing phase and an acrylic latex dispersion as the matrix.

Modified biopolymer adsorbent for the removal of dissolved organic pollutants

Industrial Crops and Products, 2011

Chemically modified starch nanocrystals were used as adsorbents for the removal of aromatic organ... more Chemically modified starch nanocrystals were used as adsorbents for the removal of aromatic organic compounds from water. The nanocrystals were chemically modified by grafting with stearate moieties which enhanced the adsorption capacity of the nanometric substrate. Their adsorption capacity ranged between 150 and 900 mol g −1 of modified nanoparticles and the adsorption isotherms could be described accurately by the Langmuir model. The adsorption kinetics followed a two-step process with first pure adsorption of the aromatic compounds onto the surface of the nanoparticles followed by a diffusion of the compounds into the layer of surface chains grafted onto the nanoparticles. Furthermore, the feasibility of using these nanoparticles in continuous flow mode processes was confirmed using a fixed bed column setup. The fixed bed column could also be regenerated by washing with ethanol and was found not to exhibit any loss in adsorption capacity over multiples adsorption-desorption cycles.