The presence of fluorides in drinking water has become a major concern worldwide due to their chronic carcinogenic behavior for humans. The development of easily accessible and environmentally friendly disposal strategies is therefore a challenge for scientists. Camel bones calcined at different temperatures and then activated with HCl at different concentrations were used for the removal of fluorides ions from an aqueous solution. The effect of activate concentration, initial adsorbate concentration, contact time and adsorption process were studied. In addition to these previous parameters, the influence of co-existing ions on the adsorption capacity of fluorides ions was investigated. The optimal dose on calcined and activated camel bones is 16g / L with a maximum adsorption capacity of 0.63 mg / g. After optimization of this parameter an application on natural waters was realized. The study showed that the calcined and activated dromedary or camel bone is a promising adsorbent for the removal of fluorides ions from fluoridated or contaminated or drinking water.
Two semi-synthetic clay-based catalysts were prepared. These catalysts were obtained by incorporating lanthanum oxide (Cat1) and chromium oxide (Cat2). They were then tested for catalytic cracking of a heavy petroleum residue (fuel). The two formulations were carried out in the presence of silica to improve their acidity then underwent an acid activation. The catalysts obtained were characterized by various methods (XRD, FTIR, ICP-OES, SEM). The results showed that the incorporation of oxides and the addition of silica improves the structural characteristics of the final products. The support used was a kaolinite rich clay, having a specific surface area of 15.26 m2/g and acidity of 14 meq/g. These values increase, respectively, to 456.14 m2/g and 50 meq/g for Cat1 and to 475.12 m2/g and 57 meq/g for Cat2. The influence of the type of oxide incorporated, the specific surface area, the porosity and the acidity of the catalysts on their catalytic activity was studied. The nature of the oxide used proved to be decisive on the quality of the catalyst. Thus Cat1, prepared with lanthanum oxide, showed the best performance in cracking the petroleum residue achieving a conversion rate of 74.13% compared to 66.53% for cat2.
The present study aims to study the impact of seasonal variations on the different forms of fluoride in groundwater in the Maradi region. The methodology consisted in carrying out three (3) water sampling campaigns at different periods, rainy season, hot season and cold season; respectively in December 2019; May 2020 and November 2020. The results obtained show that the levels of fluoride ions exist at variable levels ranging from traces to 2.84 mg/L. These results also show that, in well water, fluorine is mainly present in the F-, NaF and HF forms whatever the season; whereas, in borehole waters, the F-, NaF and MgF+ forms are those which predominate during all the seasons.
The present study aims to study the impact of seasonal variation on fluoride ion concentrations in groundwater in the Maradi region. To achieve this goal, two (2) water sampling campaigns were carried out.Sampling was carried out over the entire study area. Water samples were taken from wells and boreholes.The results of this study show that the high levels of fluoride ions are obtained during the rainy season likewise, this content of fluoride ions vary according to the variation of certain ions.
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