Ezzedine Srasra - Academia.edu (original) (raw)

Papers by Ezzedine Srasra

Colloids and Surfaces A: Physicochemical and Engineering Aspects

Journal of Water Chemistry and Technology

Surface Engineering and Applied Electrochemistry, 2009

The physico-chemical characterization of Tunisian bentonitic clays is based on the determination ... more The physico-chemical characterization of Tunisian bentonitic clays is based on the determination of the mineralogical composition (X-ray diffractions and infrared spectroscopy), chemical analysis, cation exchange capacities and the total surface area. The result given by these techniques show that these samples were smectic clay of beidellitic character. In the other hand, the activation of these clays by hydrochloric acid shows an increase of the specific surface area and favorite the clarification of vegetable oils.

Surface Engineering and Applied Electrochemistry, 2020

Commercial polyethersulfone (PES) membrane was modified and evaluated for the removal of metal io... more Commercial polyethersulfone (PES) membrane was modified and evaluated for the removal of metal ions from an aqueous solution. Modifications were carried out by a radical polymerization technique, using acrylic acid as monomer. The grafting polymerization on the membrane was developed in an aqueous medium at 60°C. Two molar initiator/monomer (3 and 7%) ratios were used to study PES-grafted-polyaceylic acid membranes. Both unmodified and modified membranes were analyzed by attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM) in order to look into their morphologies. In addition, contact angle measurements were used for membrane hydrophilicity. The ATR-FTIR spectra, SEM and AFM images confirmed that the modification on the PES membrane surface was carried out by grafting polymer of acrylic acid monomers. The results obtained show that acrylic acid may be used for the preparation of a selective membrane functionalized with carboxylic groups. Water permeability was evaluated by varying the feed pressures (4-10 bars). The flux water of unmodified membrane decreased from 10 to 6 L/h m 2 bar for modified membranes. The rejections of sodium chloride, copper chloride, and aluminum chloride were also studied for each sample. Among the metal ions tested, thevmaximum removal was reported for aluminium for grafted membrane at 7% ratio. The rejection values for grafted membranes (3 and 7%) were higher than those obtained for unmodified membranes and increased with the grafting rate.

Desalination and Water Treatment, 2011

ABSTRACT Smectite, which is a clay, is a promising material for a large number of applications. T... more ABSTRACT Smectite, which is a clay, is a promising material for a large number of applications. This is due to its specific properties i.e. cation exchange and surface complexation on amphoteric edge sites used to describe the uptake of aqueous metal species. This work addresses both properties, firstly by studying the acid-base properties of the Na and Zn-saturated smectites by using both mass and potentiometric titration methods, and secondly by studying Zn(II) adsorption as a function of pH and ionic strength. Mass titration was used to estimate the point of zero proton charge (PZC) by interpolation at different electrolyte concentrations. The potentiometric titration of the two clays suspensions between pH 3 to 11 at varying ionic strengths, 0.5 M, 0.1 M and 0.01 M NaCl was employed to characterize surface charge development on amphoteric edge sites and to graphically determinate the point of zero proton charge (PZC) which were in good agreement with those determined by mass titration. The surface charge formation was similar: positive charges can develop during the protonation reactions of Al-OH sites at edges only at pH values around the pH of PZC and deprotonation of Si-OH and Al-OH sites takes places with increasing pH of the solution resulting in negative charges at the surface edges. The experimental potentiometric data were fitted by applying diffuse double layer model (DDLM) to determine the equilibrium constants of protonation and deprotonation processes using graphic regression, ProtoFit and PHREEQC program. The adsorption of Zn(II) onto a suspension of Na-saturated smectite from Elfahs (Tunisia) was studied as a function of the pH (3, 5 and 7) and ionic strength (0.5 M and 0.01 M NaCl). The adsorption data was then fitted to Freundlich and Langmuir isotherms models.

DESALINATION AND WATER TREATMENT

Wastewater coming from the manufactory of the phosphoric acid fabrication is one of the most sign... more Wastewater coming from the manufactory of the phosphoric acid fabrication is one of the most significant environmental problems throughout the Gabes region in Tunisia. This wastewater is very loaded with fluoride (F-) and phosphate (PO 4 3-) and have an acidic pH (pH = 3.2; [F] = 1,840 mg L-1 ; [P] = 1,420 mg L-1). In this work, a smectitic clay mineral from the region (Jebel Haidoudi, Gabes) was tested for the removal of phosphate and fluoride ions from aqueous solutions. The clay samples are first purified and modified using cationic surfactant (hexadecylpyridinium (HDPy +)) at different concentrations (1.0 to 3.0 CEC of clay CEC-cationic exchange capacity) then characterized by X-ray diffraction and Fourier-transform infrared spectroscopy. A series of batch adsorption experiments were carried out. Three parameters were investigated including the effect of pH, contact time and initial fluoride and phosphate single concentrations. The experimental results show that most of the adsorption took place during the first 5 h and the optimum pH value ranged from 3 to 4. The pseudo-second-order kinetic model described better the (F) and (P) adsorption. Thus, the isotherm studies showed that the best linear-fit was obtained with the Langmuir isotherm. The adsorption selectivity of (P and F) ions in the wastewater solution by the treated clays show that the fluoride is more selective in the acid pH. Finally, organoclay (3 CEC) is the best adsorbent and could be considered as an efficient and cost-effective adsorbent.

International Journal of Applied Ceramic Technology, 2022

Journal of the Neurological Sciences, 2009

European Journal of Pain, 2009

catastrophizing and vice versa. The categories were strongly related to pain intensity, sleep, fe... more catastrophizing and vice versa. The categories were strongly related to pain intensity, sleep, fear avoidance beliefs, and function. Those with both high depression and catastrophizing had significantly worse pain and function scores. Similar, those high on either depression or catastrophizing had worse scores than those low on both depression and catastrophizing. Conclusions: These data demonstrate that some patients have high levels of depression but not catastrophizing and vice versa. Thus, depression and catastrophizing may be different concepts. Further, these were independently related to pain and function, suggesting that they play distinctive roles in back pain.

Surface Engineering and Applied Electrochemistry, 2007

TURKISH JOURNAL OF CHEMISTRY, 2019

A new heterogeneous acid catalyst based on a natural resource, Tunisian clay (Clay-H0.5), has bee... more A new heterogeneous acid catalyst based on a natural resource, Tunisian clay (Clay-H0.5), has been prepared and characterized by FT-IR, FE-SEM, and powder X-ray diffraction (XRD), as well as chemical composition, cation exchange capacity, specific surface area, and pore volume. Acid treatment for 0.5 h enlarged the surface area from 78.24 to 186.10 m 2 /g and pore volume (PV) from 0.186 to 0.281 cm 3 /g. The catalytic activity of this material was investigated in ketalization reaction under mild solvent-free conditions. This achieved up to 92% isolated yield for only 10 wt.% of the catalyst. This environmentally friendly method has advantages such as simple work-up procedure, avoidance of organic solvents, and good performance in ketalization reactions. Importantly, the Clay-H0.5 catalyst showed good recyclability where insignificant activity loss was exhibited even after six runs. Synthesized cyclic ketals were tested for their possible antileishmanial and antibacterial activities as well as antifungal activity. Biological screening showed that compound 11 had important antileishmanial activity against both L. major and L. infantum, while compound 14 also had significant antibacterial activity against four gram-positive and two gram-negative bacteria, and antifungal activity against Candida albicans, with minimal inhibitory concentration values ranging from 15.62 µg/mL to 125 µg/mL.

Surface Engineering and Applied Electrochemistry, 2009

researches have been reported the synthesis and characterization of Al(III)[1]; Zr(IV)[2]; Ti(III... more researches have been reported the synthesis and characterization of Al(III)[1]; Zr(IV)[2]; Ti(III)[3]; Fe(III)[4]; Cr(III)[5] and Rh(III)[6] pillared clays. These hydrolytic polynuclear metal cations can form thermally stable materials and micro porous structures where the clay layers are held apart by catalytically active metal oxide pillars. The porous materials are of interest mostly thanks to their potential usefulness in catalysis. In particular, chromium pillared clays have attracted the researchers attention after being tested as catalytic in a wide range of reactions such as catalytic conversion of hydrocarbons [7], ester formations [8] and elimination of water from alcohols[9]. This is due essentially to their high surface area, sizeable gallery height, porous structure and acidity [10], [11], [12], [13]. In this work the synthesis procedure includes three principal steps: first the preparation of polyoxocations by hydrolysis of certain multivalent cations which under appropriate conditions give rise to cationic polymeric species; second, the formation of the intercalated clays by ion exchange of the original charge compensating cations of swellable smectite clays by the polyoxocations synthesized in first step and finally the formation of the pillared clays by calcination of the intercalated clays to high temperatures at which the metastable polyxocations are transformed into stable oxi-hydroxidic phases, which act as pillars that support the clay layers and maintain them separated. The synthesized pillared clays were characterized focusing mainly on the properties of these new materials (basal spacing, thermal stability surface area and pore structure). Experimental Hydroxy-Cr oligomeric solution A number of methods have been developed to produce the chromium oligomers spaces that are incorporated into the interlamellar space of clays. In our case the Cr(III) oligomers have been prepared as follows: a certain amount of aqueous Na 2 CO 3 was gradually added to aqueous chromium nitrate solution or chromium chlorite solution with constant stirring until a final CO 3 2+ /Cr 3+ ratio of 1. The mixture is maintained at a temperature of 80°C for 36h [14], [15],[16]. Pillaring process Na +-clay was obtained from the Haidoudi deposit, a Tunisian interstratified illite-smectite bentonite mineral [17]. In this study the illitic fraction represents about 15% of the interstratified material; the smectitic fraction is in sodium form which pronounced a beidellitic character. The average elemental formula determined from the Na exchange purified fraction is Na 0.54 K 0.16 Ca 0.03 (Si 7.4 Al 0.6) IV (Al 2.94 Fe 0.79 Mg 0.33) VI O 22 The cationic capacity exchange of material is about 80 meq/100g of calcined clay and its nitrogen BET surface area is 100 m 2 /g. The intercalation was achieved by adding slowly a suspension of Na +-clay to the solution containing Cr (III) oligomers at room temperature. The mixture was stirred continuously for 2h to ensure that the intercalation has been completed and then the suspension was centrifuged, the supernatant removed and the green clay material repeatedly washed with distilled water and centrifuged. After intercalation the pillared clays are obtained by heating in vacuum at 350°C are denoted as Hp n meq(Cl) or Hp n meq(NO 3), where n indicates the molar ratio of CO 3 2+ to Cr 3+ cations. Analysis of products The basal spacing d 001 were measured with X-Ray diffractometer using Ni-filtered CuK α radiation by scanning 1° (2θ) min-1 between 2° and 20°. The determination of chemical composition sample was accomplished by atomic absorption spectroscopy (AAS VARIO) after dissolving the clay samples in a mixture _______________________________________________________________________________________

Ceramics International, 2021

Journal of Inclusion Phenomena and Macrocyclic Chemistry

This mini review summarizes Vicens’ research on calixdendrimers since 2004.

Desalination and Water Treatment, 2015

The objective of this study was to prepare low-cost macroporous ceramic membranes using natural k... more The objective of this study was to prepare low-cost macroporous ceramic membranes using natural kaolin and natural lignite, as porogen agent, both from Tunisia. The characteristics of this membrane have been defined to be used in filtration processes and as a support for multilayer ceramic membranes. This study includes the characterization of the raw materials in order to define optimal processing parameters to obtain the membranes. A study of the effect of lignite content has been carried out. Porosity, density and mechanical strength were the considered parameters to be optimized. A lignite percentage of 20% and a sintering temperature of 1,050˚C were chosen. Obtained membranes show good porosity above 43% but with a slightly low mechanical strength that does not exceed 20 MPa. These membranes can be considered as efficient regarding the results shown in the gas permeation tests.

Applied Clay Science, 2014

ABSTRACT

a Laboratoire Physico-Chimie des Matériaux Minéraux et leurs applications, Centre National des Re... more a Laboratoire Physico-Chimie des Matériaux Minéraux et leurs applications, Centre National des Recherches en Sciences des Matériaux, Technopole de Borj Cédria, Soliman, 8027, Tunisie. E-mail: besbesneji@yahoo.fr ; srasra.ezzedine@gmail.com b Laboratoire de Modélisation et de Méthodes de Calcul, Université Docteur Moulay Tahar de Saida, 20002 Saida, Algérie. E-mail: hadjidjebar@gmx.fr ; m_asma07@yahoo.fr ; rahmouniali@hotmail.com c Laboratoire de Synthèse Organique et Hétérocyclique, Département de Chimie, Faculté des Sciences de Tunis, Campus Universitaire, 2092, Tunis, Tunisie. E-mail: medlotfi.efrit@gmail.com

The manufacturing of low cost ceramic flat and tubular membranes via dry pressing and extrusion, ... more The manufacturing of low cost ceramic flat and tubular membranes via dry pressing and extrusion, using low cost material, namely, natural kaolin, Alumina, and lignite as a pore forming agent was the purpose in this study. These membranes are designed to be used as a support for multilayer ceramic membranes. This study includes the preparation and the characterization of the different membranes. The selected composition was 20% of lignite, 15% of Alumina and 65% of Kaolin, the membranes have been obtained at 1200 °C as a sintering temperature. The membranes show good behavior for both configurations, with a porosity above 36% and a mechanical strength of 39 MPa or the tubular membranes and 34% for the flat ones.

This study focuses on the characterization, thermal behaviour and firing properties of clays from... more This study focuses on the characterization, thermal behaviour and firing properties of clays from Cap Bon Basin, Tunisia. Chemical (inductively coupled plasma atomic emission spectroscopy) and mineralogical (X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy) characterization of the clays was carried out. Physical properties were identified using particle-size distribution and Atterberg limits tests. Differential thermal analysis/thermogravimetry, dilatometry, XRD and FTIR analyses were conducted to assess the thermal behaviour, transformations and crystalline phase development during firing. The clays studied show large proportions of silt and clay fractions. They are rich in SiO2, Al2O3 and Fe2O3 and mostly consist of illite, kaolinite, smectite and minor mixed-layer illite-smectite. Associated minerals are mainly quartz, calcite and feldspar. To monitor the firing properties, three clay mixtures referred to as M1, M2 and M3 were prepared according to the phys...

A new and clean preparation method of Polybenzidine montmorillonite conducting nanocom posites is... more A new and clean preparation method of Polybenzidine montmorillonite conducting nanocom posites is reported in this paper. Solid solid reaction was successfully used to synthesize these hybrid materials by grinding mixtures of various amounts of benzidine (BZ) and sodium montmorillonite. The characteriza tion techniques confirmed the incorporation of BZ in the nanospace of the clay and showed that BZ mole cules intercalate with a monolayer arrangement parallel to the plan of the clay layers. The amount of BZ and the presence of the clay affect deeply the melting point of benzidine and favour the formation of new crystal lographic phases. Polymerization of benzidine between the clay layers was performed using the same method by adding ammonium peroxodisulfate. The formation of four types of polymers in the interlayer space of the clay was pointed out. One of them is probably responsible for the enhancement of the conductivity when compared to the clay free polybenzidine sample.

Colloids and Surfaces A: Physicochemical and Engineering Aspects

Journal of Water Chemistry and Technology

Surface Engineering and Applied Electrochemistry, 2009

The physico-chemical characterization of Tunisian bentonitic clays is based on the determination ... more The physico-chemical characterization of Tunisian bentonitic clays is based on the determination of the mineralogical composition (X-ray diffractions and infrared spectroscopy), chemical analysis, cation exchange capacities and the total surface area. The result given by these techniques show that these samples were smectic clay of beidellitic character. In the other hand, the activation of these clays by hydrochloric acid shows an increase of the specific surface area and favorite the clarification of vegetable oils.

Surface Engineering and Applied Electrochemistry, 2020

Commercial polyethersulfone (PES) membrane was modified and evaluated for the removal of metal io... more Commercial polyethersulfone (PES) membrane was modified and evaluated for the removal of metal ions from an aqueous solution. Modifications were carried out by a radical polymerization technique, using acrylic acid as monomer. The grafting polymerization on the membrane was developed in an aqueous medium at 60°C. Two molar initiator/monomer (3 and 7%) ratios were used to study PES-grafted-polyaceylic acid membranes. Both unmodified and modified membranes were analyzed by attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM) in order to look into their morphologies. In addition, contact angle measurements were used for membrane hydrophilicity. The ATR-FTIR spectra, SEM and AFM images confirmed that the modification on the PES membrane surface was carried out by grafting polymer of acrylic acid monomers. The results obtained show that acrylic acid may be used for the preparation of a selective membrane functionalized with carboxylic groups. Water permeability was evaluated by varying the feed pressures (4-10 bars). The flux water of unmodified membrane decreased from 10 to 6 L/h m 2 bar for modified membranes. The rejections of sodium chloride, copper chloride, and aluminum chloride were also studied for each sample. Among the metal ions tested, thevmaximum removal was reported for aluminium for grafted membrane at 7% ratio. The rejection values for grafted membranes (3 and 7%) were higher than those obtained for unmodified membranes and increased with the grafting rate.

Desalination and Water Treatment, 2011

ABSTRACT Smectite, which is a clay, is a promising material for a large number of applications. T... more ABSTRACT Smectite, which is a clay, is a promising material for a large number of applications. This is due to its specific properties i.e. cation exchange and surface complexation on amphoteric edge sites used to describe the uptake of aqueous metal species. This work addresses both properties, firstly by studying the acid-base properties of the Na and Zn-saturated smectites by using both mass and potentiometric titration methods, and secondly by studying Zn(II) adsorption as a function of pH and ionic strength. Mass titration was used to estimate the point of zero proton charge (PZC) by interpolation at different electrolyte concentrations. The potentiometric titration of the two clays suspensions between pH 3 to 11 at varying ionic strengths, 0.5 M, 0.1 M and 0.01 M NaCl was employed to characterize surface charge development on amphoteric edge sites and to graphically determinate the point of zero proton charge (PZC) which were in good agreement with those determined by mass titration. The surface charge formation was similar: positive charges can develop during the protonation reactions of Al-OH sites at edges only at pH values around the pH of PZC and deprotonation of Si-OH and Al-OH sites takes places with increasing pH of the solution resulting in negative charges at the surface edges. The experimental potentiometric data were fitted by applying diffuse double layer model (DDLM) to determine the equilibrium constants of protonation and deprotonation processes using graphic regression, ProtoFit and PHREEQC program. The adsorption of Zn(II) onto a suspension of Na-saturated smectite from Elfahs (Tunisia) was studied as a function of the pH (3, 5 and 7) and ionic strength (0.5 M and 0.01 M NaCl). The adsorption data was then fitted to Freundlich and Langmuir isotherms models.

DESALINATION AND WATER TREATMENT

Wastewater coming from the manufactory of the phosphoric acid fabrication is one of the most sign... more Wastewater coming from the manufactory of the phosphoric acid fabrication is one of the most significant environmental problems throughout the Gabes region in Tunisia. This wastewater is very loaded with fluoride (F-) and phosphate (PO 4 3-) and have an acidic pH (pH = 3.2; [F] = 1,840 mg L-1 ; [P] = 1,420 mg L-1). In this work, a smectitic clay mineral from the region (Jebel Haidoudi, Gabes) was tested for the removal of phosphate and fluoride ions from aqueous solutions. The clay samples are first purified and modified using cationic surfactant (hexadecylpyridinium (HDPy +)) at different concentrations (1.0 to 3.0 CEC of clay CEC-cationic exchange capacity) then characterized by X-ray diffraction and Fourier-transform infrared spectroscopy. A series of batch adsorption experiments were carried out. Three parameters were investigated including the effect of pH, contact time and initial fluoride and phosphate single concentrations. The experimental results show that most of the adsorption took place during the first 5 h and the optimum pH value ranged from 3 to 4. The pseudo-second-order kinetic model described better the (F) and (P) adsorption. Thus, the isotherm studies showed that the best linear-fit was obtained with the Langmuir isotherm. The adsorption selectivity of (P and F) ions in the wastewater solution by the treated clays show that the fluoride is more selective in the acid pH. Finally, organoclay (3 CEC) is the best adsorbent and could be considered as an efficient and cost-effective adsorbent.

International Journal of Applied Ceramic Technology, 2022

Journal of the Neurological Sciences, 2009

European Journal of Pain, 2009

catastrophizing and vice versa. The categories were strongly related to pain intensity, sleep, fe... more catastrophizing and vice versa. The categories were strongly related to pain intensity, sleep, fear avoidance beliefs, and function. Those with both high depression and catastrophizing had significantly worse pain and function scores. Similar, those high on either depression or catastrophizing had worse scores than those low on both depression and catastrophizing. Conclusions: These data demonstrate that some patients have high levels of depression but not catastrophizing and vice versa. Thus, depression and catastrophizing may be different concepts. Further, these were independently related to pain and function, suggesting that they play distinctive roles in back pain.

Surface Engineering and Applied Electrochemistry, 2007

TURKISH JOURNAL OF CHEMISTRY, 2019

A new heterogeneous acid catalyst based on a natural resource, Tunisian clay (Clay-H0.5), has bee... more A new heterogeneous acid catalyst based on a natural resource, Tunisian clay (Clay-H0.5), has been prepared and characterized by FT-IR, FE-SEM, and powder X-ray diffraction (XRD), as well as chemical composition, cation exchange capacity, specific surface area, and pore volume. Acid treatment for 0.5 h enlarged the surface area from 78.24 to 186.10 m 2 /g and pore volume (PV) from 0.186 to 0.281 cm 3 /g. The catalytic activity of this material was investigated in ketalization reaction under mild solvent-free conditions. This achieved up to 92% isolated yield for only 10 wt.% of the catalyst. This environmentally friendly method has advantages such as simple work-up procedure, avoidance of organic solvents, and good performance in ketalization reactions. Importantly, the Clay-H0.5 catalyst showed good recyclability where insignificant activity loss was exhibited even after six runs. Synthesized cyclic ketals were tested for their possible antileishmanial and antibacterial activities as well as antifungal activity. Biological screening showed that compound 11 had important antileishmanial activity against both L. major and L. infantum, while compound 14 also had significant antibacterial activity against four gram-positive and two gram-negative bacteria, and antifungal activity against Candida albicans, with minimal inhibitory concentration values ranging from 15.62 µg/mL to 125 µg/mL.

Surface Engineering and Applied Electrochemistry, 2009

researches have been reported the synthesis and characterization of Al(III)[1]; Zr(IV)[2]; Ti(III... more researches have been reported the synthesis and characterization of Al(III)[1]; Zr(IV)[2]; Ti(III)[3]; Fe(III)[4]; Cr(III)[5] and Rh(III)[6] pillared clays. These hydrolytic polynuclear metal cations can form thermally stable materials and micro porous structures where the clay layers are held apart by catalytically active metal oxide pillars. The porous materials are of interest mostly thanks to their potential usefulness in catalysis. In particular, chromium pillared clays have attracted the researchers attention after being tested as catalytic in a wide range of reactions such as catalytic conversion of hydrocarbons [7], ester formations [8] and elimination of water from alcohols[9]. This is due essentially to their high surface area, sizeable gallery height, porous structure and acidity [10], [11], [12], [13]. In this work the synthesis procedure includes three principal steps: first the preparation of polyoxocations by hydrolysis of certain multivalent cations which under appropriate conditions give rise to cationic polymeric species; second, the formation of the intercalated clays by ion exchange of the original charge compensating cations of swellable smectite clays by the polyoxocations synthesized in first step and finally the formation of the pillared clays by calcination of the intercalated clays to high temperatures at which the metastable polyxocations are transformed into stable oxi-hydroxidic phases, which act as pillars that support the clay layers and maintain them separated. The synthesized pillared clays were characterized focusing mainly on the properties of these new materials (basal spacing, thermal stability surface area and pore structure). Experimental Hydroxy-Cr oligomeric solution A number of methods have been developed to produce the chromium oligomers spaces that are incorporated into the interlamellar space of clays. In our case the Cr(III) oligomers have been prepared as follows: a certain amount of aqueous Na 2 CO 3 was gradually added to aqueous chromium nitrate solution or chromium chlorite solution with constant stirring until a final CO 3 2+ /Cr 3+ ratio of 1. The mixture is maintained at a temperature of 80°C for 36h [14], [15],[16]. Pillaring process Na +-clay was obtained from the Haidoudi deposit, a Tunisian interstratified illite-smectite bentonite mineral [17]. In this study the illitic fraction represents about 15% of the interstratified material; the smectitic fraction is in sodium form which pronounced a beidellitic character. The average elemental formula determined from the Na exchange purified fraction is Na 0.54 K 0.16 Ca 0.03 (Si 7.4 Al 0.6) IV (Al 2.94 Fe 0.79 Mg 0.33) VI O 22 The cationic capacity exchange of material is about 80 meq/100g of calcined clay and its nitrogen BET surface area is 100 m 2 /g. The intercalation was achieved by adding slowly a suspension of Na +-clay to the solution containing Cr (III) oligomers at room temperature. The mixture was stirred continuously for 2h to ensure that the intercalation has been completed and then the suspension was centrifuged, the supernatant removed and the green clay material repeatedly washed with distilled water and centrifuged. After intercalation the pillared clays are obtained by heating in vacuum at 350°C are denoted as Hp n meq(Cl) or Hp n meq(NO 3), where n indicates the molar ratio of CO 3 2+ to Cr 3+ cations. Analysis of products The basal spacing d 001 were measured with X-Ray diffractometer using Ni-filtered CuK α radiation by scanning 1° (2θ) min-1 between 2° and 20°. The determination of chemical composition sample was accomplished by atomic absorption spectroscopy (AAS VARIO) after dissolving the clay samples in a mixture _______________________________________________________________________________________

Ceramics International, 2021

Journal of Inclusion Phenomena and Macrocyclic Chemistry

This mini review summarizes Vicens’ research on calixdendrimers since 2004.

Desalination and Water Treatment, 2015

The objective of this study was to prepare low-cost macroporous ceramic membranes using natural k... more The objective of this study was to prepare low-cost macroporous ceramic membranes using natural kaolin and natural lignite, as porogen agent, both from Tunisia. The characteristics of this membrane have been defined to be used in filtration processes and as a support for multilayer ceramic membranes. This study includes the characterization of the raw materials in order to define optimal processing parameters to obtain the membranes. A study of the effect of lignite content has been carried out. Porosity, density and mechanical strength were the considered parameters to be optimized. A lignite percentage of 20% and a sintering temperature of 1,050˚C were chosen. Obtained membranes show good porosity above 43% but with a slightly low mechanical strength that does not exceed 20 MPa. These membranes can be considered as efficient regarding the results shown in the gas permeation tests.

Applied Clay Science, 2014

ABSTRACT

a Laboratoire Physico-Chimie des Matériaux Minéraux et leurs applications, Centre National des Re... more a Laboratoire Physico-Chimie des Matériaux Minéraux et leurs applications, Centre National des Recherches en Sciences des Matériaux, Technopole de Borj Cédria, Soliman, 8027, Tunisie. E-mail: besbesneji@yahoo.fr ; srasra.ezzedine@gmail.com b Laboratoire de Modélisation et de Méthodes de Calcul, Université Docteur Moulay Tahar de Saida, 20002 Saida, Algérie. E-mail: hadjidjebar@gmx.fr ; m_asma07@yahoo.fr ; rahmouniali@hotmail.com c Laboratoire de Synthèse Organique et Hétérocyclique, Département de Chimie, Faculté des Sciences de Tunis, Campus Universitaire, 2092, Tunis, Tunisie. E-mail: medlotfi.efrit@gmail.com

The manufacturing of low cost ceramic flat and tubular membranes via dry pressing and extrusion, ... more The manufacturing of low cost ceramic flat and tubular membranes via dry pressing and extrusion, using low cost material, namely, natural kaolin, Alumina, and lignite as a pore forming agent was the purpose in this study. These membranes are designed to be used as a support for multilayer ceramic membranes. This study includes the preparation and the characterization of the different membranes. The selected composition was 20% of lignite, 15% of Alumina and 65% of Kaolin, the membranes have been obtained at 1200 °C as a sintering temperature. The membranes show good behavior for both configurations, with a porosity above 36% and a mechanical strength of 39 MPa or the tubular membranes and 34% for the flat ones.

This study focuses on the characterization, thermal behaviour and firing properties of clays from... more This study focuses on the characterization, thermal behaviour and firing properties of clays from Cap Bon Basin, Tunisia. Chemical (inductively coupled plasma atomic emission spectroscopy) and mineralogical (X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy) characterization of the clays was carried out. Physical properties were identified using particle-size distribution and Atterberg limits tests. Differential thermal analysis/thermogravimetry, dilatometry, XRD and FTIR analyses were conducted to assess the thermal behaviour, transformations and crystalline phase development during firing. The clays studied show large proportions of silt and clay fractions. They are rich in SiO2, Al2O3 and Fe2O3 and mostly consist of illite, kaolinite, smectite and minor mixed-layer illite-smectite. Associated minerals are mainly quartz, calcite and feldspar. To monitor the firing properties, three clay mixtures referred to as M1, M2 and M3 were prepared according to the phys...

A new and clean preparation method of Polybenzidine montmorillonite conducting nanocom posites is... more A new and clean preparation method of Polybenzidine montmorillonite conducting nanocom posites is reported in this paper. Solid solid reaction was successfully used to synthesize these hybrid materials by grinding mixtures of various amounts of benzidine (BZ) and sodium montmorillonite. The characteriza tion techniques confirmed the incorporation of BZ in the nanospace of the clay and showed that BZ mole cules intercalate with a monolayer arrangement parallel to the plan of the clay layers. The amount of BZ and the presence of the clay affect deeply the melting point of benzidine and favour the formation of new crystal lographic phases. Polymerization of benzidine between the clay layers was performed using the same method by adding ammonium peroxodisulfate. The formation of four types of polymers in the interlayer space of the clay was pointed out. One of them is probably responsible for the enhancement of the conductivity when compared to the clay free polybenzidine sample.