The tannery effluent from the wet finishing stage is a complex, highly charged rejected of organi... more The tannery effluent from the wet finishing stage is a complex, highly charged rejected of organic and mineral matter. It has variable characteristics over time and is not readily biodegradable. Its physicochemical treatment by adsorption on the smectitic clay of Khlédia proves to be effective. The reduction of dye, BOD, COD, heavy metals are remarkable. The decrease of the conductivity is due to the phenomenon of the cations adsorption on the negatively charged support colloids.
The smectite rich natural clays of upper Cretaceous of Jebel Romana (South of Tunisia) and Lower ... more The smectite rich natural clays of upper Cretaceous of Jebel Romana (South of Tunisia) and Lower Oligocene of Khledia area (Norh of Tunisia) were evaluated as adsorbents for anionic (Acid Brown 75) and cationic (Basic Yellow 28) dyes. XRD, XRF, FTIR, S BET , CEC and pH pzc were used to study the physico-chemical properties of clay samples. The experimental results showed that, the adsorption was pH dependent with a high adsorption capacity of BY28 in basic range and high adsorption of AB75 in acidic range. The maximum adsorption capacities, predicted by the Langmuir model, were 76.92 and 8.33 mg/g for BY28 and AB75, respectively. Smectitic clays showed to be an advantageous adsorbents in terms of price and availability, they use without purification or chemical modifications, which is beneficial for the economy of the treatment.
Smectitic clays from 12 deposits located in the Meridional Atlas domain (Tunisia) are explored fo... more Smectitic clays from 12 deposits located in the Meridional Atlas domain (Tunisia) are explored for manufacturing of expanded aggregates. Two types of firing processes (slow and quick firing) were carried out, and properties of the bloated products were examined. Used raw materials are mainly composed of smectite, kaolinite and illite phases with quartz, calcite, dolomite and feldspars as impurities. They contain high amounts of fluxes (Fe 2 O 3 , CaO, MgO, Na 2 O and K 2 O) with CaO and Fe 2 O 3 dominating others. Quick firing or "flash heat" must be preceded by two hours drying at 350°C in order to avoid any aggregate explosion which seems to be related to the fineness of a raw material. The clay fineness appears to be the cause of ball explosion. Clay aggregates were heated at the maximum bloating temperature (1170 °C) during 5 min. and then characterized through a determination of the apparent density, the mechanical resistance corresponding to the rupture under point c...
The use of clays for therapeutic purposes is mainly related to their high absorbent and adsorbent... more The use of clays for therapeutic purposes is mainly related to their high absorbent and adsorbent properties. In dermatology and cosmeties (topical applications), clays are used due to their high swelling, high plasticity, high specific surface and high ion exchange properties. In this paper, mineralogical, chemical and technological properties of some Tunisian smectitic clays are reported with the aim to assess their suitability to be used for therapeutic external applications. Properties of these clays have been compared to those of the bentonite of Porto Santo Island (PSBT) of the Madeira archipelago (Portugal), considered to be very interesting for therapeutic treatment on the basis of their technological characterization (CEC, specific surface, exchangeable cations, specific heat, cooling rate and abrasivity). Among the investigated clays the HMD1, TFL1, BRD1 and AYD1 seem to be the most appropriate for topical applications as cataplasms or mud baths. This work is conducted to ...
Comptes Rendus De L Academie Des Sciences Serie Ii Fascicule a-Sciences De La Terre Et Des Planetes, 2001
Eocene continental facies discovery around the Kasserine archipelago in Rheouis, Boudinar and Cha... more Eocene continental facies discovery around the Kasserine archipelago in Rheouis, Boudinar and Chamsi Jebels in the central-meridional Tunisia: new palaeogeographic implications. The Rhéouis and Boudinar Eocene outcrops located along the Tunisian 'north-south axis' show continental deposits similar to those already described in the west-central and meridional Atlas in the Jebel Chaambi and Chebket Bouloufa. The field investigations of these levels conduct to the discovery of Bulimes' terrestrial Gastropods known in the Mediterranean domain. The presence of palygorskite in the clay minerals confirms the emerged tendency of these deposits. The continental palaeogeography might have been induced by the Triassic halokinetic movements along the Atlasic anticlines. 2001 Académie des sciences / Éditions scientifiques et médicales Elsevier SAS Eocene / continental deposits / Rheouis Jebel / Boudinar Jebel / Chamsi Jebel / palygorskite / Tunisia * Correspondance et tirés à part.
Clays are used as non-specific anti-diarrheic materials in several commercial pharmaceutics. Thei... more Clays are used as non-specific anti-diarrheic materials in several commercial pharmaceutics. Their employment is based on the high sorptive capacities of special clay minerals, in particular smectites and fibrous clays. This use greatly increases the value of these materials. This study was made in order to determine the possible use of some Tunisian clays for the treatment of diarrhea. With this aim, the mineralogical and chemical compositions of the studied samples were determined and subsequently, cation exchange capacities and specific surfaces areas were measured. Finally, the specific adsorption of two microorganism responsible of this disorder ( Echerichia coli and Stapphylococcus aureus ) was studied and compared to the adsorption of the dye (methylene blue) mainly used to quantify the ability of a pharmaceutical-grade clay as anti-diarrheic material. According to the mineralogical characterization, the studied samples contain variable amounts of phyllosilicates, with minor quantities of quartz and calcite. In particular, four samples (AYD1, AYD2, HMD1 and BRD1) are mainly made up of smectite (> 66%), whereas the rest (OMV1, SDA1, CAA1 and CBL9) are illitic and kaolinitic clays. Chemical analysis revealed relatively high contents of Fe 2 O 3 . Smectite and illite kaolinite rich samples showed, as expected, higher sorptive capacities of the studied microorganism, with values reaching 95% of Staphylococcus aureus and 65% of Escherichia coli retained after 90 minutes of interaction. These results are in agreement with those obtained with mehtylene blue, showing promising abilities of most of the studied Tunisian clays to be used in the treatment of these gastric disorders.
Engineering Geology for Society and Territory - Volume 5, 2014
In this study, we assessed the potentialities of using the phosphate washing by-products as row m... more In this study, we assessed the potentialities of using the phosphate washing by-products as row materials for the production of lightweight aggregates. Sludge samples from different washing plants have been physic-chemically characterized. Slurries were dried, milled and shaped into spherical pellets. These raw aggregates were sintered for 5 min in the laboratory kiln at different temperatures between 1,120 and 1,180 °C. The bloating potential of the lightweight aggregates as well as the effect of the firing temperatures on their properties (expansion, apparent density, water absorption and compressive strength) were assessed. The mineralogical data shows that the collected sludge samples are mainly composed of carbonates, francolite, clinoptilolite, quartz and feldspars; smectite, palygorskite and sepiolite are also present as clayey fractions. Chemically, the samples exhibited significant amount of SiO2, CaO, and P2O5. When sintered, the aggregates expand; this expansion results from the concomitant reaction of gas release and viscous phase formation. The produced lightweight aggregates revealed acceptable technological properties with apparent density values often lower than 0.9 g/cm3. Moreover, good expansion (60 % in volume) and water absorption (close to 10 %) were obtained. These results are encouraging and allow considering the studied sludge as promising material for the production of lightweight aggregates.
The adsorption of Pb 2+ ions onto Tunisian smectite-rich clay in aqueous solution was studied in ... more The adsorption of Pb 2+ ions onto Tunisian smectite-rich clay in aqueous solution was studied in a batch system. Four samples of clay (AYD, AYDh, AYDs, AYDc) were used. The raw AYD clay was sampled in the Coniacian-Early Campanian of Jebel Aïdoudi in El Hamma area (South of Tunisia). AYDh and AYDs corresponds to AYD activated by 2.5 mol/l hydrochloric acid and 2.5 mol/l sulphuric acid, respectively. AYDc corresponds to AYD calcined at different temperatures (100, 200, 300, 400, 500 and 600 • C). The raw AYD clay was characterized by X-ray diffraction, chemical analysis, infrared spectroscopy and coupled DTA-TGA. Specific surface area of all the clay samples was determined from nitrogen adsorption isotherms. Preliminary adsorption tests showed that sulphuric acid and hydrochloric acid activation of raw AYD clay enhanced its adsorption capacity for Pb 2+ ions. However, the uptake of Pb 2+ by AYDs was very high compared to that by AYDh. This fact was attributed to the greater solubility of clay minerals in sulphuric acid compared to hydrochloric acid. Thermic activation of AYD clay reduced the Pb 2+ uptake as soon as calcination temperature reaches 200 • C. All these preliminary results were well correlated to the variation of the specific surface area of the clay samples. The ability of AYDs sample to remove Pb 2+ from aqueous solutions has been studied at different operating conditions: contact time, adsorbent amount, metal ion concentration and pH. Kinetic experiments showed that the sorption of lead ions on AYDs was very fast and the equilibrium was practically reached after only 20 min. The results revealed also that the adsorption of lead increases with an increase in the solution pH from 1 to 4.5 and then decreases, slightly between pH 4.5 and 6, and rapidly at pH 6.5 due to the precipitation of some Pb 2+ ions. The equilibrium data were analysed using Langmuir isotherm model. The maximum adsorption capacity (Q 0) increased from 25 to 25.44 mg/g with increasing temperature from 25 to 40 • C. Comparative study between sulphuric acid activated clay (AYDs) and powder activated carbon (PAC) for the adsorption of lead was also conducted. The results showed that sulphuric acid activated clay is more efficient than PAC.
The adsorption of a textile dye, namely, Indanthrene Blue RS (C.I. Vat Blue 4) onto smectite-rich... more The adsorption of a textile dye, namely, Indanthrene Blue RS (C.I. Vat Blue 4) onto smectite-rich clayey rock (AYD) and its sulphuric acid-activated products (AYDS) in aqueous solution was studied in a batch system with respect to contact time, pH, and temperature. The adsorbents employed were characterized by X-ray diffraction, infrared spectroscopy and specific surface area, cation exchange capacity and point of zero charge were also estimated. The effect of contact time on dye adsorption showed that the equilibrium was reached after a contact time of 40 min for the both adsorbents. The optimum pH for dye retention was found 6.0 for AYDS and 7.3 for AYD. The equilibrium adsorption data were analysed using the Langmuir and Freundlich isotherms. The adsorption capacities (Q(m)) for AYD and AYDS were found 13.92 mg/g and 17.85 mg/g, respectively. The effect of temperature on the adsorption was also investigated; adsorption of Indanthrene Blue RS is an endothermic process. This study demonstrates that all the considered adsorbents can be used as an alternative emerging technology for water treatment.
Smectite-rich claystone-marlstone samples from 12 outcrops located in the Southern Atlas domain o... more Smectite-rich claystone-marlstone samples from 12 outcrops located in the Southern Atlas domain of Tunisia were investigated with regard to manufacture of lightweight aggregates (LWAs). The clayey materials mainly consist of smectite, kaolinite and illite, together with quartz, calcite, dolomite and feldspars as accessory components. 10-12 mm pellets were prepared from wet paste and initially heated to 600°C, 700°C or 800°C (depending on the raw material) for at least 2 h in order to avoid any explosion of the aggregate. The pellets were then subjected to a quick firing process at 1180°C. The addition of 15% of quartz sand (b 250 μm grain size) to the raw materials was found to improve some required pre-treatments and give better expansion properties to some of the aggregates. The addition of 1% used automobile oil to the clay and quartz sand mixtures caused the formation of more gas and a drop in bloating temperature. The obtained LWAs were characterized by physical properties such as apparent density, mechanical resistance, water absorption and expansion. The laboratory results were comparable to those of two commercial LWAs from France (Argidécor®) and Portugal (LECA®) and provide new openings for the utilization of Tunisian claystone in civil engineering work or in agricultural applications.
The tannery effluent from the wet finishing stage is a complex, highly charged rejected of organi... more The tannery effluent from the wet finishing stage is a complex, highly charged rejected of organic and mineral matter. It has variable characteristics over time and is not readily biodegradable. Its physicochemical treatment by adsorption on the smectitic clay of Khlédia proves to be effective. The reduction of dye, BOD, COD, heavy metals are remarkable. The decrease of the conductivity is due to the phenomenon of the cations adsorption on the negatively charged support colloids.
The smectite rich natural clays of upper Cretaceous of Jebel Romana (South of Tunisia) and Lower ... more The smectite rich natural clays of upper Cretaceous of Jebel Romana (South of Tunisia) and Lower Oligocene of Khledia area (Norh of Tunisia) were evaluated as adsorbents for anionic (Acid Brown 75) and cationic (Basic Yellow 28) dyes. XRD, XRF, FTIR, S BET , CEC and pH pzc were used to study the physico-chemical properties of clay samples. The experimental results showed that, the adsorption was pH dependent with a high adsorption capacity of BY28 in basic range and high adsorption of AB75 in acidic range. The maximum adsorption capacities, predicted by the Langmuir model, were 76.92 and 8.33 mg/g for BY28 and AB75, respectively. Smectitic clays showed to be an advantageous adsorbents in terms of price and availability, they use without purification or chemical modifications, which is beneficial for the economy of the treatment.
Smectitic clays from 12 deposits located in the Meridional Atlas domain (Tunisia) are explored fo... more Smectitic clays from 12 deposits located in the Meridional Atlas domain (Tunisia) are explored for manufacturing of expanded aggregates. Two types of firing processes (slow and quick firing) were carried out, and properties of the bloated products were examined. Used raw materials are mainly composed of smectite, kaolinite and illite phases with quartz, calcite, dolomite and feldspars as impurities. They contain high amounts of fluxes (Fe 2 O 3 , CaO, MgO, Na 2 O and K 2 O) with CaO and Fe 2 O 3 dominating others. Quick firing or "flash heat" must be preceded by two hours drying at 350°C in order to avoid any aggregate explosion which seems to be related to the fineness of a raw material. The clay fineness appears to be the cause of ball explosion. Clay aggregates were heated at the maximum bloating temperature (1170 °C) during 5 min. and then characterized through a determination of the apparent density, the mechanical resistance corresponding to the rupture under point c...
The use of clays for therapeutic purposes is mainly related to their high absorbent and adsorbent... more The use of clays for therapeutic purposes is mainly related to their high absorbent and adsorbent properties. In dermatology and cosmeties (topical applications), clays are used due to their high swelling, high plasticity, high specific surface and high ion exchange properties. In this paper, mineralogical, chemical and technological properties of some Tunisian smectitic clays are reported with the aim to assess their suitability to be used for therapeutic external applications. Properties of these clays have been compared to those of the bentonite of Porto Santo Island (PSBT) of the Madeira archipelago (Portugal), considered to be very interesting for therapeutic treatment on the basis of their technological characterization (CEC, specific surface, exchangeable cations, specific heat, cooling rate and abrasivity). Among the investigated clays the HMD1, TFL1, BRD1 and AYD1 seem to be the most appropriate for topical applications as cataplasms or mud baths. This work is conducted to ...
Comptes Rendus De L Academie Des Sciences Serie Ii Fascicule a-Sciences De La Terre Et Des Planetes, 2001
Eocene continental facies discovery around the Kasserine archipelago in Rheouis, Boudinar and Cha... more Eocene continental facies discovery around the Kasserine archipelago in Rheouis, Boudinar and Chamsi Jebels in the central-meridional Tunisia: new palaeogeographic implications. The Rhéouis and Boudinar Eocene outcrops located along the Tunisian 'north-south axis' show continental deposits similar to those already described in the west-central and meridional Atlas in the Jebel Chaambi and Chebket Bouloufa. The field investigations of these levels conduct to the discovery of Bulimes' terrestrial Gastropods known in the Mediterranean domain. The presence of palygorskite in the clay minerals confirms the emerged tendency of these deposits. The continental palaeogeography might have been induced by the Triassic halokinetic movements along the Atlasic anticlines. 2001 Académie des sciences / Éditions scientifiques et médicales Elsevier SAS Eocene / continental deposits / Rheouis Jebel / Boudinar Jebel / Chamsi Jebel / palygorskite / Tunisia * Correspondance et tirés à part.
Clays are used as non-specific anti-diarrheic materials in several commercial pharmaceutics. Thei... more Clays are used as non-specific anti-diarrheic materials in several commercial pharmaceutics. Their employment is based on the high sorptive capacities of special clay minerals, in particular smectites and fibrous clays. This use greatly increases the value of these materials. This study was made in order to determine the possible use of some Tunisian clays for the treatment of diarrhea. With this aim, the mineralogical and chemical compositions of the studied samples were determined and subsequently, cation exchange capacities and specific surfaces areas were measured. Finally, the specific adsorption of two microorganism responsible of this disorder ( Echerichia coli and Stapphylococcus aureus ) was studied and compared to the adsorption of the dye (methylene blue) mainly used to quantify the ability of a pharmaceutical-grade clay as anti-diarrheic material. According to the mineralogical characterization, the studied samples contain variable amounts of phyllosilicates, with minor quantities of quartz and calcite. In particular, four samples (AYD1, AYD2, HMD1 and BRD1) are mainly made up of smectite (> 66%), whereas the rest (OMV1, SDA1, CAA1 and CBL9) are illitic and kaolinitic clays. Chemical analysis revealed relatively high contents of Fe 2 O 3 . Smectite and illite kaolinite rich samples showed, as expected, higher sorptive capacities of the studied microorganism, with values reaching 95% of Staphylococcus aureus and 65% of Escherichia coli retained after 90 minutes of interaction. These results are in agreement with those obtained with mehtylene blue, showing promising abilities of most of the studied Tunisian clays to be used in the treatment of these gastric disorders.
Engineering Geology for Society and Territory - Volume 5, 2014
In this study, we assessed the potentialities of using the phosphate washing by-products as row m... more In this study, we assessed the potentialities of using the phosphate washing by-products as row materials for the production of lightweight aggregates. Sludge samples from different washing plants have been physic-chemically characterized. Slurries were dried, milled and shaped into spherical pellets. These raw aggregates were sintered for 5 min in the laboratory kiln at different temperatures between 1,120 and 1,180 °C. The bloating potential of the lightweight aggregates as well as the effect of the firing temperatures on their properties (expansion, apparent density, water absorption and compressive strength) were assessed. The mineralogical data shows that the collected sludge samples are mainly composed of carbonates, francolite, clinoptilolite, quartz and feldspars; smectite, palygorskite and sepiolite are also present as clayey fractions. Chemically, the samples exhibited significant amount of SiO2, CaO, and P2O5. When sintered, the aggregates expand; this expansion results from the concomitant reaction of gas release and viscous phase formation. The produced lightweight aggregates revealed acceptable technological properties with apparent density values often lower than 0.9 g/cm3. Moreover, good expansion (60 % in volume) and water absorption (close to 10 %) were obtained. These results are encouraging and allow considering the studied sludge as promising material for the production of lightweight aggregates.
The adsorption of Pb 2+ ions onto Tunisian smectite-rich clay in aqueous solution was studied in ... more The adsorption of Pb 2+ ions onto Tunisian smectite-rich clay in aqueous solution was studied in a batch system. Four samples of clay (AYD, AYDh, AYDs, AYDc) were used. The raw AYD clay was sampled in the Coniacian-Early Campanian of Jebel Aïdoudi in El Hamma area (South of Tunisia). AYDh and AYDs corresponds to AYD activated by 2.5 mol/l hydrochloric acid and 2.5 mol/l sulphuric acid, respectively. AYDc corresponds to AYD calcined at different temperatures (100, 200, 300, 400, 500 and 600 • C). The raw AYD clay was characterized by X-ray diffraction, chemical analysis, infrared spectroscopy and coupled DTA-TGA. Specific surface area of all the clay samples was determined from nitrogen adsorption isotherms. Preliminary adsorption tests showed that sulphuric acid and hydrochloric acid activation of raw AYD clay enhanced its adsorption capacity for Pb 2+ ions. However, the uptake of Pb 2+ by AYDs was very high compared to that by AYDh. This fact was attributed to the greater solubility of clay minerals in sulphuric acid compared to hydrochloric acid. Thermic activation of AYD clay reduced the Pb 2+ uptake as soon as calcination temperature reaches 200 • C. All these preliminary results were well correlated to the variation of the specific surface area of the clay samples. The ability of AYDs sample to remove Pb 2+ from aqueous solutions has been studied at different operating conditions: contact time, adsorbent amount, metal ion concentration and pH. Kinetic experiments showed that the sorption of lead ions on AYDs was very fast and the equilibrium was practically reached after only 20 min. The results revealed also that the adsorption of lead increases with an increase in the solution pH from 1 to 4.5 and then decreases, slightly between pH 4.5 and 6, and rapidly at pH 6.5 due to the precipitation of some Pb 2+ ions. The equilibrium data were analysed using Langmuir isotherm model. The maximum adsorption capacity (Q 0) increased from 25 to 25.44 mg/g with increasing temperature from 25 to 40 • C. Comparative study between sulphuric acid activated clay (AYDs) and powder activated carbon (PAC) for the adsorption of lead was also conducted. The results showed that sulphuric acid activated clay is more efficient than PAC.
The adsorption of a textile dye, namely, Indanthrene Blue RS (C.I. Vat Blue 4) onto smectite-rich... more The adsorption of a textile dye, namely, Indanthrene Blue RS (C.I. Vat Blue 4) onto smectite-rich clayey rock (AYD) and its sulphuric acid-activated products (AYDS) in aqueous solution was studied in a batch system with respect to contact time, pH, and temperature. The adsorbents employed were characterized by X-ray diffraction, infrared spectroscopy and specific surface area, cation exchange capacity and point of zero charge were also estimated. The effect of contact time on dye adsorption showed that the equilibrium was reached after a contact time of 40 min for the both adsorbents. The optimum pH for dye retention was found 6.0 for AYDS and 7.3 for AYD. The equilibrium adsorption data were analysed using the Langmuir and Freundlich isotherms. The adsorption capacities (Q(m)) for AYD and AYDS were found 13.92 mg/g and 17.85 mg/g, respectively. The effect of temperature on the adsorption was also investigated; adsorption of Indanthrene Blue RS is an endothermic process. This study demonstrates that all the considered adsorbents can be used as an alternative emerging technology for water treatment.
Smectite-rich claystone-marlstone samples from 12 outcrops located in the Southern Atlas domain o... more Smectite-rich claystone-marlstone samples from 12 outcrops located in the Southern Atlas domain of Tunisia were investigated with regard to manufacture of lightweight aggregates (LWAs). The clayey materials mainly consist of smectite, kaolinite and illite, together with quartz, calcite, dolomite and feldspars as accessory components. 10-12 mm pellets were prepared from wet paste and initially heated to 600°C, 700°C or 800°C (depending on the raw material) for at least 2 h in order to avoid any explosion of the aggregate. The pellets were then subjected to a quick firing process at 1180°C. The addition of 15% of quartz sand (b 250 μm grain size) to the raw materials was found to improve some required pre-treatments and give better expansion properties to some of the aggregates. The addition of 1% used automobile oil to the clay and quartz sand mixtures caused the formation of more gas and a drop in bloating temperature. The obtained LWAs were characterized by physical properties such as apparent density, mechanical resistance, water absorption and expansion. The laboratory results were comparable to those of two commercial LWAs from France (Argidécor®) and Portugal (LECA®) and provide new openings for the utilization of Tunisian claystone in civil engineering work or in agricultural applications.
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