33 research outputs found

    Characterization of natural and chemically modified kaolinite from Mako (Senegal) to remove lead from aqueous solutions

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    The chemical and sorption properties of clay minerals from the Mako area, Senegal, were investigated using FTIR spectroscopy, X-ray diffraction, scanning electron microscopy equipped with an X-ray energy dispersion spectrometer, thermal analysis and chemical analysis. The clay sample is essentially dominated by kaolinite and quartz as also shown by treatment with ethylene glycol and dimethylsulfoxide (DMSO). The clay fraction of this natural clay was organically modified by grafting with 3-aminopropyltriethoxysilane (APTES) in order to improve significantly its retention ability of heavy metals. The silane groups of the APTES reagent were partly grafted on the surface of platy kaolinite particles and the remaining ethoxy groups could be hydrolysed by aqueous treatment. The natural clay, its clay fraction and the organo-functionalized clay (with APTES) were investigated as adsorbents for the removal of Pb(II) from aqueous solutions. Evidence for an organic grafting has been demonstrated by comparing the spectroscopic characteristics of the natural clay and those of its chemically modified derivatives. The effects of different parameters (i.e. initial Pb(II) concentration and contact time) on the adsorption efficiency were studied. For an initial concentration of 10 mg L–1 Pb(II), the adsorption was maximized after 30 min contact time both for the raw material and its clay fraction and after 90 min for the APTES grafted clay. Although the maximum of sorption for the APTES grafted clay is reached with slower kinetics, this maximum amount of Pb(II) uptake at room temperature (X max) is significantly higher since it is 0.99 mg g–1 for the raw clay, 1.46 mg g–1 for its clay fraction and 3.02 mg g–1 for the organically modified clay, i.e. three times greater than the raw clay

    Grasses (Poaceae) From Senegal: New Records Checklist, Biogeographical Affinities and Biological Types

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    Poaceae is one of the most diverse families in Senegal's flora after Fabaceae. It has been the subject of several studies but many species were not taken into account in the evaluation of the current state of its diversity. This paper provides a checklist of new grasses encountered in Senegal. After a detailed scrutiny of the literature and herbarium specimens, we ascertain their identity and report them as new records to the grass flora of Senegal. A total of 24 new species have been listed belonging to 15 genera of which the most represented is Sporobolus with 5 species. The other genera such as Digitaria, Eragrostis, Perotis, Setaria, and Trichanthecium on the one hand and Aristida, Chloris, Cymbopogon, Enteropogon, Leptochloa, Oryza, Panicum, Schizachyrium, Urochloa on the other hand have two and one species respectively. The chorological spectrum shows the dominance of African species (45.83%) followed by those of Afro-Asian origin (33.33%). Like the overall flora of Senegal, this new grass flora is of tropical nature with a preponderance of Sudano-Zambesian species (50%) followed by Guinean- Congolese-Sudano-Zambesian species (29.17%) at continental scale. Biological types based on the life form shows therophytes (62.50%) are predominant, followed by hemicryptophytes (29.17%) and geophytes (8.33%). Taking these new data into account would allow a more precise determination of the Senegalese grass flora composition

    Mineralogical and physico-chemical characterizations of clay from Keur Saër (Senegal)

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    There is interest in exploiting and developing natural resources, particularly deposits of natural clays. Senegal has several clay mineral deposits for which chemical and mineralogical compositions have been little studied. Some of these natural materials are nowadays used in pottery and ceramics. To extend applications, a better basic knowledge is required and, for this objective, the raw clay and separated <2 μm clay fraction from Keur Saër (Senegal) were subjected to chemical and mineralogical studies. Several techniques including X-ray diffraction (XRD), thermal analysis (TG-DTA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), N2 adsorption-desorption isotherms, cation exchange capacity (CEC) measurements and solid state nuclear magnetic resonance (NMR) have been used to characterize the material. It was found that the raw clay and the separated clay fraction consist of a mineral mixture in which kaolinite is the main component. 29Si and 27Al MAS-NMR spectra show the presence of silicon atoms linked to three other silicon atoms via an oxygen atom and six coordinated Al atoms. Significant increases in the specific surface area and cation exchange capacity were observed on purification, reaching a maximum of about 73.2 m2g–1 and 9.5 meq/100 g for the separated fine clay fraction while the values for the raw material were around 28.9 m2g–1 and 7.3 meq/100 g

    Structure et caractéristiques de la flore adventice de la ferme agricole de l’Université Gaston Berger de Saint-Louis (Sénégal)

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    This present study was conducted to determine the structure and characteristics of the adventitious flora of the agricultural farm of Gaston Berger University (UGB) located in Saint Louis, Senegal. A species inventory was carried out using the "tour de champ" technique which consists of going through a plot in different directions and recording all the species present in the studied area. The inventoried flora is composed of 149 species distributed among 90 genera belonging to 30 families which are dominated by the Poaceae (18.8%) and the Fabaceae (15.4%). This flora is also characterized by the predominance of the therophytes and the chamephytes which represent 79.9% and 10.7% of recorded species, respectively. From a chorologic standpoint, pantropical (29.5%) and African (28.2%) species account for more than half of the species (57.7%). The quantitative analysis of this flora reveals that rare or accidental species are more represented (52%) followed by frequent species (16%) and secondary species (15%)

    Révision du genre Digitaria Haller (Poaceae) au Sénégal : proposition d’une clé de détermination pour une meilleure identification des espèces

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    Le genre Digitaria Haller (Poaceae) constitue l’un des genres les plus diversifiés des Poaceae du Sénégal avec 19 espèces. Bien qu’il y ait une monographie mondiale du genre, la détermination des espèces reste difficile et repose essentiellement sur les caractères de l’appareil reproducteur. Ce travail, qui est une révision du genre Digitaria au Sénégal, est entrepris afin de rechercher des caractères pertinents sur l’appareil végétatif et d’améliorer l’identification des espèces. Pour ce faire, une description détaillée des différents organes des spécimens étudiés est réalisée à l’aide d’une loupe binoculaire. Les résultats de l’étude montrent que la pubescence de l’épillet est un caractère essentiel pour l’identification des espèces. De plus, les longueurs relatives de la glume supérieure et de la lemma inférieure sont très intéressantes pour la discrimination d’espèces affines. Toutefois, l’étude supplémentaire des organes végétatifs de la plante adulte montre que certains caractères végétatifs pourraient contribuer considérablement à l’amélioration de l’identification des espèces. Il s’agit du cycle biologique, de la pubescence de la ligule, de la marge du limbe, des noeuds et des entre-noeuds du chaume qui sont des caractères plus faciles à observer. Une clé de détermination basée sur des caractères végétatifs et reproducteurs des espèces est ainsi élaborée.© 2015 International Formulae Group. All rights reserved.Mots clés: Digitaria, Poaceae, révision, clé de détermination, SénégalEnglish Title: Review of Digitaria Haller (Poaceae) genus in Senegal: suggestion of a determination key for a better identification of speciesEnglish AbstractThe genus Digitaria Haller (Poaceae) is one of the most diversified genera of Poaceae in Senegal with 19 species. Although it has a worldwide monograph of the genus, the identification of species remains difficult and mainly based on the characteristics of the reproductive system. This work, which is a review of the genus  Digitaria in Senegal, is undertaken in order to search relevant characteristics on the vegetative system and to improve the identification of species. To do this, a detailed description of the various organs of the studied specimens is carried out using a binocular microscope. The results of the study show that the pubescence of the spikelet is an essential characteristic for the identification of species. Moreover, the relative lengths of the upper glume and lower lemma are very interesting for the discrimination of species closely related. However, the additional study of vegetative organs of the adult plant shows that some vegetative characteristics could contribute considerably to the improvement of the identification of species. It is the biological cycle, the pubescence of the ligule, the margin of the leaf blade, nodes and internodes of the thatch which are characteristics easier to observe. A key of determination based on vegetative and reproductive characteristics of species is thus worked out.© 2015 International Formulae Group. All rights reserved.Mots clés: Digitaria, Poaceae, review, key of determination, Senega

    Study of the woody flora in the mining areas of the commune of Sabodala (KĂ©dougou, Senegal)

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    Le Sénégal oriental est une région très riche de par sa flore, sa faune mais également de par son sous-sol qui renferme d’intéressants indices ou gisements d’or, d’uranium, de fer, de cuivre, de nickel, de lithium, de marbre, de molybdène et de chrome. Cette exploitation n’est toutefois pas sans conséquences car les activités extractives causent d’énormes préjudices notamment à l’environnement. La présente étude se fixe comme objectif d’établir la situation de référence de la flore ligneuse de la zone. Ainsi à partir d’un échantillonnage de type aléatoire stratifié et d’un maillage systématique, l’étude de la flore du site a été faite en utilisant la méthode de l’inventaire itinérant. La flore de la zone d’exploitation minière de la commune de Sabodala et ses environs est riche de 103 espèces distribuées dans 75 genres et 32 familles. Les Fabaceae, Combretaceae et Malvaceae sont les familles majoritaires de cette flore. Le genre Combretum est le plus riche avec 7 espèces. Le spectre biologique montre une prédominance des microphanérophytes et des mésophanérophytes. Les espèces de l’élément-base soudanien sont majoritaires avec 35,3 %, indiquant le caractère soudanien de la zone. Ces résultats sont très importants dans les processus de reconstitution de la flore de la zone. Mots-clés: flore ligneuse, Goumbati-Kobokoto, savanes, zone soudanienneEastern Senegal is a very rich region for its flora and fauna but also for its subsoil which contains interesting gold, uranium, iron, copper, copper, nickel, lithium, marble, molybdenum and chromium deposits. However, this exploitation is not without consequences, as mining activities cause enormous damage, particularly to the environment. The objective of this study is to establish the reference situation of the woody flora of the area. Thus, using stratified random sampling and a systematic grid, the study of the site's flora was carried out using the mobile inventory method. The flora of the mining area of the commune of Sabodala and its surroundings is rich in 103 species distributed in 75 genera and 32 families. The Fabaceae, Combretaceae and Malvaceae are the majority families of this flora. The Combretum genus is the richest with 7 species. The biological spectrum shows a predominance of microphanerophytes and mesophanerophytes. The species of the Sudanian base element are the majority with 35.3%, indicating the Sudanian character of the area. These results are very important in the processes of reconstitution of the flora of the zone. Keywords: woody flora, Goumbati-Kobokoto, savannas, Sudanian zon

    Migration of intrauterine device into the pelvic cavity: exploration strategy and management in African environment

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    IUD migration is a rare complication. We report our experience in the treatment of five cases of uterine perforation and migration of IUDs. The average age of patients was 34.6 years, an average parity was 4. All patients felt an unusual pain during insertion of the IUD Tcu 380A. The location of the IUD was done through ultrasound and hysterography. Removal by laparoscopy was performed in all cases. The immediate impacts of the surgery were simple. Hysterography has its place in the location of the migrated IUD. Prevention is a good IUD insertion technique

    Laparoscopic management of cervical and endometrial cancer in Africa: experience of the National Hospital Centre of Pikine

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    Background: Laparotomy represents the standard historical surgical approach to these cancers. Process of treatment of benign adnexal pathologies to the emergence of a new pathway for the management of these cancerous pathologies.Methods: Our prospective study from December 2016 to December 2018 included 10 patients with early-stage uterine cancer and endometrial cancer confirmed by MRI. The characteristics of patients, their cancer, their intervention and morbidity were revealed.Results: Our results show that the average age of the patients was 63 years; There were 2 cases of cervical cancer and 8 cases of endometrial cancer. For cervical cancer, it was essentially squamous cell carcinoma; one patient was at stage Ia2 and the other at stage Ib1. For endometrial cancers, squamous cell carcinoma was 80%; 6 patients were in stage IB and 2 in stage IC. Of the 10 patients undergoing surgery, 9 had laparoscopic colpohysterectomy and lymphadectomy and one complementary laparoscopic lymphadenectomy. The average number of lymph nodes removed was 9 and no lymph node metastasis was found. In the immediate postoperative period, one patient had transient urinary incontinence and another had vaginal slice lymphorhea.Conclusions: The main interest of this practice is to be the least morbid possible for patients at the early stage. With our short experience, we obtained a reduction in operating time, a reduction in hospital stay, a decrease in the consumption of analgesics and antibiotics postoperatively and a reduction in per and postoperative complications
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