In the present paper, the valorisation of two residues: Posidonia oceanica and date palm rachis w... more In the present paper, the valorisation of two residues: Posidonia oceanica and date palm rachis was investigated. First, their chemical composition was studied and showed that they present amounts of holocellulose, lignin and cellulose similar to those encountered in softwood and hardwood. Extractives in different solvents and ash contents are relatively high. Moreover, ash composition assessment showed that silicon is the major component (17.7%) for P. oceanica. The high ash quantity and the low DP (about 370) may be considered as serious disadvantages of P. oceanica, in the pulping and papermaking context. Oppositely, the properties of rachis date palm and those of the ensuing pulp, obtained from a classical soda-anthraquinone cooking, demonstrated the suitability of this agricultural by-product for papermaking. Preliminary tests conducted on unrefined pulp suspensions and handsheets from date palm rachis in terms of freeness, Water Retention Value and mechanical properties allowed confirming the good quality of date palm rachis fibres.
ABSTRACT Posidonia oceanica a dominant Mediterranean Sea grass was used as a starting material to... more ABSTRACT Posidonia oceanica a dominant Mediterranean Sea grass was used as a starting material to produce nanofibrillar cellulose. Thus, NFC gel was produced by the disintegration in a high pressure homogenizer of cellulose pulp extracted from P. oceanica. The ensuing NFC suspension was characterized in terms of fibrillation yield, transparency, rheological behavior and morphological features. The reinforcing potential of the ensuing NFC was also investigated using dynamic mechanical analysis (DMA) from measurements carried out on nanocomposites films prepared by casting a mixture of NFC suspension and commercial acrylic latex. The prepared materials have showed promising mechanical properties.
Different grades of cellulose nanofibrils (CNF) were prepared from Posidonia oceanica balls and l... more Different grades of cellulose nanofibrils (CNF) were prepared from Posidonia oceanica balls and leaves (POB and POL). Pretreatment using 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation was performed to facilitate the fibrillation during ultrafine friction grinding process. The ensuing CNF batches were compared in terms of morphology and degree of fibrillation. The rheological properties of the produced CNF suspensions were also analyzed for varying doses of sodium hypochlorite used during the TEMPO- mediated oxidation procedure. The stronger fibrous network structures were formed when increasing the oxidant concentration, which was confirmed by the increase of the storage moduli value. P. oceanica balls were found to undergo stronger fibrillation and, consequently, to form stronger networks, compared to P. oceanica leaves, when using equivalent concentration of the oxidizing agent.
Sodium carboxymethylcellulose (CMCNa) is an anionic water soluble polyelectrolyte widely used in ... more Sodium carboxymethylcellulose (CMCNa) is an anionic water soluble polyelectrolyte widely used in many industrial sectors including food, textiles, papers, adhesives, paints, pharmaceuticals, cosmetics and mineral processing. CMCNa was produced by chemical modification of cellulose, and represents many advantages: natural, renewable, non-toxic and biodegradable. In this study, different kinds of CMCNa, prepared from an agricultural waste date palm rachis, were tested as eco-friendly flocculants for drinking water treatment and their performances as flocculants in turbidity removal enhancement were assessed. The prepared materials were characterized by the degree of substitution (DS) and polymerisation (DP). The study of the effect of some experimental parameters on the coagulation-flocculation performance, using the prepared materials combined with aluminium sulphate (as coagulant), showed that the best conditions for turbidity treatment were given for pH 8, coagulant dose 20 mg/L, f...
Essential oils from odorous and volatile compounds possessing several therapeutic benefits are co... more Essential oils from odorous and volatile compounds possessing several therapeutic benefits are considered of a paramount importance in everyday human life. This study deals with a comparative study of essential oils from different parts of an aromatic plant Kundmannia sicula (L.) DC. (Apiaceae) growing in Tunisia. The hydro-distilled essential oils of the leaves and inflorescences with mature seeds (IMS) of K. sicula were analysed for the first time by gas chromatography equipped with flame ionisation detector and gas chromatography coupled with mass spectrometry. Fifty leaves and 47 IMS constituents were identified, accounting for 97.9% and 98.2% of the total oil, respectively. The major compounds identified from the leaves and IMS oils were isocurcumenol (9.9-10.1%), hexadecanoic acid (9.5-10.9%), spathulenol (6.9-3.4%), 10-epi-γ-eudesmol (6.3-5.5%), α-cubebene (5.9-6.1%) and trans-dihydro occidentalol (52-6.6%). The essential oil consists mainly of oxygenated monoterpenes (50.7-53.2%).
In the present study, cellulose nanocrystals (CNC) were isolated from Posidonia oceanica balls an... more In the present study, cellulose nanocrystals (CNC) were isolated from Posidonia oceanica balls and leaves. CNC was prepared from this marine biomass by sulfuric acid hydrolysis (H2SO4) treatment. The raw fibers were firstly isolated by a delignification-bleaching process then the acid hydrolysis treatment was performed at 55°C during 40min under mechanical stirring. The ensuing CNCs were characterized by their morphological and thermal properties using transmission electron microscopy (TEM) and thermal gravimetric analysis (TGA), respectively. Nanocomposite materials using the CNC extracted from marine biomass were obtained by casting and evaporating a mixture of this suspension with poly(styrene-co-butyl acrylate). The effect of CNC loading on mechanical and thermal properties was studied. Dynamic mechanical analysis (DMA) results showed a strong reinforcing effect of CNC that depends on their origin (balls or leaves). The difference was attributed not only to differences in the aspect ratio of CNC but also to the stiffness of the percolating network of nanoparticles.
Dyes obtained from different natural sources have emerged as an important alternative to syntheti... more Dyes obtained from different natural sources have emerged as an important alternative to synthetic dyes. In this study, optimisation of natural colorant non-conventional extraction technique from olive waste was investigated using response surface methodology. The combined effects of extraction conditions on total phenolic content (TPC) and relative color strength (K/S) were studied using a three-level three-factor Box-Behnken design. The optimum conditions for dye extraction were found to be 0.14mol/L, 62.11min, 71.23°C and 4.5g for sodium hydroxide concentration, extraction time, temperature, and mass of the waste, respectively. The efficiency of extraction under these optimum conditions was found to be 1133.86mg/L of phenolics and relative colour strength (K/S) equal to 23.22. Further, Fourier Transform Infrared Spectroscopy was used to identify the major chemical groups in the extracted dye.
In the present paper, the valorisation of two residues: Posidonia oceanica and date palm rachis w... more In the present paper, the valorisation of two residues: Posidonia oceanica and date palm rachis was investigated. First, their chemical composition was studied and showed that they present amounts of holocellulose, lignin and cellulose similar to those encountered in softwood and hardwood. Extractives in different solvents and ash contents are relatively high. Moreover, ash composition assessment showed that silicon is the major component (17.7%) for P. oceanica. The high ash quantity and the low DP (about 370) may be considered as serious disadvantages of P. oceanica, in the pulping and papermaking context. Oppositely, the properties of rachis date palm and those of the ensuing pulp, obtained from a classical soda-anthraquinone cooking, demonstrated the suitability of this agricultural by-product for papermaking. Preliminary tests conducted on unrefined pulp suspensions and handsheets from date palm rachis in terms of freeness, Water Retention Value and mechanical properties allowed confirming the good quality of date palm rachis fibres.
ABSTRACT Posidonia oceanica a dominant Mediterranean Sea grass was used as a starting material to... more ABSTRACT Posidonia oceanica a dominant Mediterranean Sea grass was used as a starting material to produce nanofibrillar cellulose. Thus, NFC gel was produced by the disintegration in a high pressure homogenizer of cellulose pulp extracted from P. oceanica. The ensuing NFC suspension was characterized in terms of fibrillation yield, transparency, rheological behavior and morphological features. The reinforcing potential of the ensuing NFC was also investigated using dynamic mechanical analysis (DMA) from measurements carried out on nanocomposites films prepared by casting a mixture of NFC suspension and commercial acrylic latex. The prepared materials have showed promising mechanical properties.
Different grades of cellulose nanofibrils (CNF) were prepared from Posidonia oceanica balls and l... more Different grades of cellulose nanofibrils (CNF) were prepared from Posidonia oceanica balls and leaves (POB and POL). Pretreatment using 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation was performed to facilitate the fibrillation during ultrafine friction grinding process. The ensuing CNF batches were compared in terms of morphology and degree of fibrillation. The rheological properties of the produced CNF suspensions were also analyzed for varying doses of sodium hypochlorite used during the TEMPO- mediated oxidation procedure. The stronger fibrous network structures were formed when increasing the oxidant concentration, which was confirmed by the increase of the storage moduli value. P. oceanica balls were found to undergo stronger fibrillation and, consequently, to form stronger networks, compared to P. oceanica leaves, when using equivalent concentration of the oxidizing agent.
Sodium carboxymethylcellulose (CMCNa) is an anionic water soluble polyelectrolyte widely used in ... more Sodium carboxymethylcellulose (CMCNa) is an anionic water soluble polyelectrolyte widely used in many industrial sectors including food, textiles, papers, adhesives, paints, pharmaceuticals, cosmetics and mineral processing. CMCNa was produced by chemical modification of cellulose, and represents many advantages: natural, renewable, non-toxic and biodegradable. In this study, different kinds of CMCNa, prepared from an agricultural waste date palm rachis, were tested as eco-friendly flocculants for drinking water treatment and their performances as flocculants in turbidity removal enhancement were assessed. The prepared materials were characterized by the degree of substitution (DS) and polymerisation (DP). The study of the effect of some experimental parameters on the coagulation-flocculation performance, using the prepared materials combined with aluminium sulphate (as coagulant), showed that the best conditions for turbidity treatment were given for pH 8, coagulant dose 20 mg/L, f...
Essential oils from odorous and volatile compounds possessing several therapeutic benefits are co... more Essential oils from odorous and volatile compounds possessing several therapeutic benefits are considered of a paramount importance in everyday human life. This study deals with a comparative study of essential oils from different parts of an aromatic plant Kundmannia sicula (L.) DC. (Apiaceae) growing in Tunisia. The hydro-distilled essential oils of the leaves and inflorescences with mature seeds (IMS) of K. sicula were analysed for the first time by gas chromatography equipped with flame ionisation detector and gas chromatography coupled with mass spectrometry. Fifty leaves and 47 IMS constituents were identified, accounting for 97.9% and 98.2% of the total oil, respectively. The major compounds identified from the leaves and IMS oils were isocurcumenol (9.9-10.1%), hexadecanoic acid (9.5-10.9%), spathulenol (6.9-3.4%), 10-epi-γ-eudesmol (6.3-5.5%), α-cubebene (5.9-6.1%) and trans-dihydro occidentalol (52-6.6%). The essential oil consists mainly of oxygenated monoterpenes (50.7-53.2%).
In the present study, cellulose nanocrystals (CNC) were isolated from Posidonia oceanica balls an... more In the present study, cellulose nanocrystals (CNC) were isolated from Posidonia oceanica balls and leaves. CNC was prepared from this marine biomass by sulfuric acid hydrolysis (H2SO4) treatment. The raw fibers were firstly isolated by a delignification-bleaching process then the acid hydrolysis treatment was performed at 55°C during 40min under mechanical stirring. The ensuing CNCs were characterized by their morphological and thermal properties using transmission electron microscopy (TEM) and thermal gravimetric analysis (TGA), respectively. Nanocomposite materials using the CNC extracted from marine biomass were obtained by casting and evaporating a mixture of this suspension with poly(styrene-co-butyl acrylate). The effect of CNC loading on mechanical and thermal properties was studied. Dynamic mechanical analysis (DMA) results showed a strong reinforcing effect of CNC that depends on their origin (balls or leaves). The difference was attributed not only to differences in the aspect ratio of CNC but also to the stiffness of the percolating network of nanoparticles.
Dyes obtained from different natural sources have emerged as an important alternative to syntheti... more Dyes obtained from different natural sources have emerged as an important alternative to synthetic dyes. In this study, optimisation of natural colorant non-conventional extraction technique from olive waste was investigated using response surface methodology. The combined effects of extraction conditions on total phenolic content (TPC) and relative color strength (K/S) were studied using a three-level three-factor Box-Behnken design. The optimum conditions for dye extraction were found to be 0.14mol/L, 62.11min, 71.23°C and 4.5g for sodium hydroxide concentration, extraction time, temperature, and mass of the waste, respectively. The efficiency of extraction under these optimum conditions was found to be 1133.86mg/L of phenolics and relative colour strength (K/S) equal to 23.22. Further, Fourier Transform Infrared Spectroscopy was used to identify the major chemical groups in the extracted dye.
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