Thallium (I) was removed from aqueous solution by using gamma-alumina nanoparticles (γANPs) materials as nano adsorbents. Varied experimental conditions such as adsorbent dose, agitation time, initial concentration, pH, and temperature effects were carried out in batch conditions in view of the optimization of thallium (I) adsorption and the identification of the adsorption mechanisms in the system γANPs-Tl. The pH effect indicated a remarkable increase in the quantity of Tl(I) removed for pH values ranging from 4 to 8, an almost constant magnitude for pH values between 8 and 10, and a decrease for pH values above 10. Considering an initial Tl(I) concentration of 20 µg/L and an adsorbent dose of 1 g/L at a pH value of 8.5, the removal was achieved at 95.12 ± 0.02% efficiency. The pseudo-second-order kinetics and the Freundlich isotherm perfectly described the adsorption mechanism. The process of thallium (I) adsorption reaction, as highlighted by thermodynamic investigations, was found to be spontaneous and exothermic with coexistence of physisorption and chemisorption with a dominance of physisorption. The diffusion model predicted multi-linearity, suggesting an involvement of surface spread and intraparticle diffusion in the sorption process. Thallium removal was effective by using γANPs as nano adsorbents.

Thallium (Tl) is a non-essential element for human being and is considered as a highly toxic trace element at a concentration above 2 µg/L. To assess the source of thallium contamination in ground and surface waters in the locality of Yamtenga village (11°43'35.1'' N and 00°11'50.8'' W, Burkina Faso), chemical analyzes of thallium concentrations in the soils of Yamtenga village along with geological descriptions (geological map and hydrographic watershed map of the studied area) were undertaken. We found thallium concentrations in this area ranging from 1.61 mg / kg to 404.75 mg / kg. A zoned mineralization in thallium, due to the geological structure of the locality, was established in the soils, suggesting that the source of thallium contamination in ground and surface waters in the locality of Yamtenga village is of natural origin. The concentration of some heavy metals (Pb, Zn, Cd, Cu and Mn) were also evaluated in the soils of Yamtenga village and their concentration relationships with thallium were analyzed by the Pearson correlation coefficient based on matrix correlation. Moderate (0.554), low (0.408) and significant (0.999) correlations coefficients were obtained between thallium and lead, zinc, manganese respectively. Significant correlation coefficients (0.788 and 0.791) were also noted between thallium and copper, cadmium respectively. Thallium concentrations in ground and surface waters in this locality are mainly related to the interactions between water and source rocks, thallium being released following some alteration processes with other heavy metals elements especially manganese.

Gamma-alumina nanoparticles (γANPs) were obtained from a low-cost process by using natural bauxites. The γANPs materials were characterized by X-ray powder diffraction (XRPD), Fourier-transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) theory, scanning electron microscopy (SEM), atomic force microscopy (AFM), and were functionalized with N-cetyl-N, N, N, trimethylammonium bromide (CTAB), leading to CTAB modified γ-alumina nanoparticles (γANPs-CTAB). These novel functionalized γANPs-CTAB were characterized by XRPD, FTIR, and were used as an adsorbent for bisphenol-A (BPA) removal from water. Batch investigations were conducted under different experimental conditions (e.g., adsorbent dose, agitation time, initial concentration, and pH and surfactant loading) in order to optimize BPA adsorption and to identify the adsorption mechanisms in the system γANPs-CTAB-BPA. The effect of pH on the adsorption showed that the quantity of BPA removed increased remarkably until the pH value was 4, then remained almost constant until the pH value was up to 10, and then decreased for pH values greater than 10. For an initial BPA concentration of 20 mg/L and an adsorbent dose of 12.5 g/L at a pH value of 10, the removal efficiency achieved was 91.80 ± 0.21%. The adsorption mechanism was perfectly described by pseudo-second-order kinetics and the Langmuir isotherm. γANPs-CTAB materials were found to be effective adsorbents for BPA removal from water.

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