Adsorption of organic/inorganic pollutants on natural substances : Kaolin, Calotropis procera roots, dates stones

Le premier objectif des études présentées dans cette thèse est de caractériser un gisement argileux kaolinique de la région du sud-ouest Algérien qui n’a jamais été exploité auparavent, d’améliorer les propriétés de surface de cette argile suite à des modifications réalisées par revêtement avec un aminosilane (APTES) ou par échange cationique avec un agent tensioactif (CTAB), ce qui nous a permis de développer les sites actifs à la surface de ce matériau. Les matériaux préparés ont été caractérisés par DRX, ATG, IRTF, MET et MEB. Deux autres matériaux d’origine végétale d’une grande abondance au sud-ouest Algérien qui sont les racines de la plante Calotropis Procera et les noyaux de dattes de Feggous sont aussi caractérisés. Le second objectif de cette étude est l’application de ces matériaux dans l'élimination de différents types de polluants en solutions aqueuses : métaux lourds (Zn(II) et Mn(II)) et Colorants synthétiques anionique et cationique (Rouge Congo et Violet de gentiane) pour une mise en évidence de l’efficacité des matériaux argileux et végétaux vis-à-vis de l'adsorption de ces polluants. L’étude de l’adsorption consiste à discuter les effets du temps de contact, pH et la concentration initiale du soluté en utilisant une technique d'adsorption en batch. L’effet de la température a permis de réaliser une étude thermodynamique pour définir la nature des phénomènes d’adsorption. En outre, différents modèles de cinétique (premier et second ordres) et d’isothermes d’adsorption (Langmuir et Freundlich) sont utilisés pour l’évaluation de la capacité des supports kaoliniques naturel et modifiés (K08, KC et KS) et des supports végétaux (CP et ND) à adsorber ces polluants organiques et inorganiques. Le kaolin naturel (K08) a montré une bonne affinité vis-à-vis tous les polluants avec des capacités d’adsorption remarquables ; cette capacité a considérablement évolué par la modification. Le kaolin modifié (KS) s’avère le meilleur adsorbant pour ces types de polluants (métaux lourds et colorants synthétiques). Les racines de CP présentent une très bonne affinité pour les métaux lourds, alors que les noyaux de dattes donnent des résultats plus remarquables pour la biosorption des colorantsThe first aim of the studies presented in this thesis is to characterize a kaolin clay deposit in south-western Algerian region which has never been exploited, to improve the surface properties of the clay due to changes made by coating with an amino silane (APTES) or cationic exchange with a surfactant (CTAB), which allowed us to develop the active sites on the surface of this material. The prepared materials were characterized by XRD, TGA, FTIR and SEM. Two other vegetable materials of great abundance in the southwest Algerian who are the roots of the plant Calotropis Procera and Feggous date stones are also characterized. The second aim of this study is the application of these materials in removing different kinds of pollutants in aqueous solutions: heavy metals (Zn (II) and Mn (II)) and anionic and cationic synthetic dyes (Congo red and Purple gentian) to the effectiveness demonstration of the clay and vegetable materials to adsorb these pollutants. The study of adsorption is to discuss the effects of contact time, pH and initial concentration of the solute using a batch adsorption technique. The effect of temperature has achieved a thermodynamic study to define the nature of adsorption phenomena. In addition, different kinetic models (first and second order) and adsorption isotherms (Langmuir and Freundlich) are used to assess the ability of clay materials (K08, KC and KS) and vegetable materials (CP and ND) to adsorb such organic and inorganic pollutants. The natural clay (K08) showed good affinity towards all pollutants with remarkable adsorption capacity, this capacity has evolved considerably by modifications. The modified kaolin (KS) proves the best adsorbent for these types of pollutants (heavy metals and synthetic dyes). The roots of CP have a very good affinity for heavy metals, while the date stones give more remarkable results for biosorption dye

Adsorption des polluants organiques et inorganiques sur des substances naturelles : Kaolin, racines de Calotropis procera et noyaux de dattes

Accès restreint aux membres de l'Université de Lorraine jusqu'au 2017-12-31The first aim of the studies presented in this thesis is to characterize a kaolin clay deposit in south-western Algerian region which has never been exploited, to improve the surface properties of the clay due to changes made by coating with an amino silane (APTES) or cationic exchange with a surfactant (CTAB), which allowed us to develop the active sites on the surface of this material. The prepared materials were characterized by XRD, TGA, FTIR and SEM. Two other vegetable materials of great abundance in the southwest Algerian who are the roots of the plant Calotropis Procera and Feggous date stones are also characterized. The second aim of this study is the application of these materials in removing different kinds of pollutants in aqueous solutions: heavy metals (Zn (II) and Mn (II)) and anionic and cationic synthetic dyes (Congo red and Purple gentian) to the effectiveness demonstration of the clay and vegetable materials to adsorb these pollutants. The study of adsorption is to discuss the effects of contact time, pH and initial concentration of the solute using a batch adsorption technique. The effect of temperature has achieved a thermodynamic study to define the nature of adsorption phenomena. In addition, different kinetic models (first and second order) and adsorption isotherms (Langmuir and Freundlich) are used to assess the ability of clay materials (K08, KC and KS) and vegetable materials (CP and ND) to adsorb such organic and inorganic pollutants. The natural clay (K08) showed good affinity towards all pollutants with remarkable adsorption capacity, this capacity has evolved considerably by modifications. The modified kaolin (KS) proves the best adsorbent for these types of pollutants (heavy metals and synthetic dyes). The roots of CP have a very good affinity for heavy metals, while the date stones give more remarkable results for biosorption dyesLe premier objectif des études présentées dans cette thèse est de caractériser un gisement argileux kaolinique de la région du sud-ouest Algérien qui n’a jamais été exploité auparavent, d’améliorer les propriétés de surface de cette argile suite à des modifications réalisées par revêtement avec un aminosilane (APTES) ou par échange cationique avec un agent tensioactif (CTAB), ce qui nous a permis de développer les sites actifs à la surface de ce matériau. Les matériaux préparés ont été caractérisés par DRX, ATG, IRTF, MET et MEB. Deux autres matériaux d’origine végétale d’une grande abondance au sud-ouest Algérien qui sont les racines de la plante Calotropis Procera et les noyaux de dattes de Feggous sont aussi caractérisés. Le second objectif de cette étude est l’application de ces matériaux dans l'élimination de différents types de polluants en solutions aqueuses : métaux lourds (Zn(II) et Mn(II)) et Colorants synthétiques anionique et cationique (Rouge Congo et Violet de gentiane) pour une mise en évidence de l’efficacité des matériaux argileux et végétaux vis-à-vis de l'adsorption de ces polluants. L’étude de l’adsorption consiste à discuter les effets du temps de contact, pH et la concentration initiale du soluté en utilisant une technique d'adsorption en batch. L’effet de la température a permis de réaliser une étude thermodynamique pour définir la nature des phénomènes d’adsorption. En outre, différents modèles de cinétique (premier et second ordres) et d’isothermes d’adsorption (Langmuir et Freundlich) sont utilisés pour l’évaluation de la capacité des supports kaoliniques naturel et modifiés (K08, KC et KS) et des supports végétaux (CP et ND) à adsorber ces polluants organiques et inorganiques. Le kaolin naturel (K08) a montré une bonne affinité vis-à-vis tous les polluants avec des capacités d’adsorption remarquables ; cette capacité a considérablement évolué par la modification. Le kaolin modifié (KS) s’avère le meilleur adsorbant pour ces types de polluants (métaux lourds et colorants synthétiques). Les racines de CP présentent une très bonne affinité pour les métaux lourds, alors que les noyaux de dattes donnent des résultats plus remarquables pour la biosorption des colorant

Effect of the Degree of Ionization on the Insertion of Polyvinylpyridinium Salts into Bentonite

The present work reports the effect of the degree of α ionization of poly(4-vinylpyridinium) salts (P4VPS) on the insertion of these polymer salts into bentonite. Nanocomposite materials made of a Na-montmorillonite mineral with poly(4-vinylpyridinium) salts (P4VPS) have been synthesised and characterised. The modified samples were studied by X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The basic spacing of unmodified montmorillonite, determined by XRD, was measured to be 1.38 nm; it was found to increase after modification up to 1.50 nm. The insertion capacity of P4VPS into bentonite increased with the increasing degree of quaternisated nitrogen sites in the polymer

Biosorptive Removal of Zinc from Aqueous Solution by Algerian <i>Calotropis procera</i> Roots

International audiencePotentially toxic trace elements, such as zinc, with high levels in water are very serious problems in many places around the world, sometimes in relation to natural sources and in other cases to anthropogenic ones. Adsorption process is among the most effective techniques for removing of many heavy metal ions from different types of water. In this study, an attempt has been made to investigate the efficiency of Calotropis procera roots (CP) in removing of Zn(II) from aqueous solution by using batch mode technique. During the removal process, the effects of solution pH, Zn concentrations and contact time on adsorption efficiency by CP roots were studied. Experimental equilibrium data were analyzed by the Langmuir and Freundlich isotherm models. The results showed that the best fit was achieved with the Langmuir isotherm equation with maximum ad-sorption capacity of 9.69 mg/g. The biosorption of Zn(II) was a fast process and followed the pseudo-second-order kinetic

Adsorption of Congo Red from Aqueous Solution Using CTAB-Kaolin from Bechar Algeria

International audienceCetyltrimethylammonium bromide-modified kaolin (CTAB-kaolin or KC) was prepared and tested as an adsorbent for an anionic dye Congo red (CR) removal from aqueous solution in comparison with natural kaolin (K). The effect of various experimental parameters was investigated using a batch adsorption technique. In this manner, the adsorption isotherms and adsorption kinetics of CR on K and KC were examined. The isothermal data could be well described by the Langmuir equation and the dynamical data fit well with the pseudo-second-order kinetic model. The ad-sorption capacity of modified kaolin KC (24.46 mg/g) was found to be around 4 times higher than that of natural kaolin K (5.94 mg/g). The KC demonstrated the highest adsorption capacity by removing over 98% of CR after ten minutes of contact. These results indicate that CTAB-kaolin could be employed as low-cost alternative to activated carbon in wastewater treatment for the removal of colour which comes from industrial effluents of textile activities, tanning or printing

Removal of Zn (II) from Aqueous Solution onto Kaolin by Batch Design

International audienceThe Algerian kaolin clay was investigated to remove Zn(II) heavy metal ion from aqueous solution. The effect of contact time, initial metal ion concentration, pH and temperature was experimentally studied in batch mode to evaluate the adsorption capacity, kinetic, thermodynamic and equilibrium. The extent of zinc adsorption increased with increasing initial concentration of adsorbat, pH and temperature. The linear Langmuir and Freundlich models were applied to describe equilibrium isotherms and both models fitted well. The monolayer adsorption capacity for Zn(II) ions was 12.23 mg per g of kaolin clay at pH 6.1 and 25˚C. Dubinin-Radushkevich (D-R) isotherm model was also applied to the equilibrium data. Thermodynamic parameters showed that the adsorption of Zn(II) onto kaolin clay was spontaneous and endothermic process in nature. Furthermore, the Lagergren-first-order and pseudo-second-order models were used to describe the kinetic data. The experimental data fitted well the pseudo-second-order kinetic. As a result, the kaolin clay may be used for removal of zinc from aqueous media

Adsorption of Zinc in Aqueous Solution onto Natural Maghnite Modified by 3-Aminopropyltriethoxysilane

International audienceZinc (II) was immobilised directly onto clay, maghnite (M13), and after their amine functionalisation with (3-aminopropyl)triethoxysilane (APTES). The APTES-functionalised maghnite (MS) showed higher zinc loading than only maghnite, indicating that the clay functionalisation enhanced the Zn(II) removal. The hydrophilic properties of the clay surface have been modified, but not turned into hydrophobic ones. The graft has indeed a polar amine group and the chain length is too short to present an important hydrophobic character. X-ray diffraction indicated that their original structure had been preserved. This new hybrid organic–inorganic material may be a good alternative for separation and pre-concentration of heavy metal ions. Both adsorbents were characterised by FTIR, XRD, TG and SEM. Both adsorbents showed maximum adsorption of the metal ions at pH 6.1 for Mag and pH 9 for MS. The adsorption processes followed pseudo-second-order kinetics. The Langmuir model best fits the adsorption data

Adsorption of Nickel in Aqueous Solution onto Natural Maghnite

International audienceMaghnite clay obtained from Tlemcen, Algeria was investigated to remove heavy metal ion from wastewater. Thus, the present study includes the adsorption of Ni(II) in aqueous solution on maghnite clay through the process of adsorption under various conditions (with variable concentration of metal ion, temperature, pH and mixing time). Increasing pH favours the removal of metal ions till they are precipitated as the insoluble hydroxides. The uptake is rapid with maximum adsorption being observed within 10 min for Ni(II). In addition, the results obtained from adsorption isotherm indicated that these data can be better fitted with the Langmuir and Freundlich equations than the Dubinin-Radushke-vich (D-R) equation