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Electrical resistivity imaging and 3D geological modelling of the sedimentary architecture of the Sanaga foodplain (Cameroon, Central Africa)

Yene Atangana Joseph Quentin, Menanga Tokouet Renaud, Mbida Yem Lionel, Onana Enama Leandre, Ntyame Ella Marie Olivia, Ndjigui Paul-Désiré

Acta Geophysica

2023

Vol. 71, no. 2

735--755

The sedimentary architecture of the Middle Sanaga deposits in the Central Cameroon Region was studied by combining sedimentological and surface geoelectrical techniques. Lithologic columns from hand augers and pits were correlated to geoelectrical profiles. All of these data were analysed to determine the volumes of lithological units that constitute significant potential geomaterial deposits (gravels, sands, and clays). From surface to depth, geoelectrical results show four main units: conductive GU1 (100 Ωm), semi-resistive GU2 (800 Ωm), resistive UG3 (1000–2000 Ωm), and highly resistive GU4 (over 2000 Ωm). The calibration results identify three lithological units: LU1 composed of poorly sorted pebbles and gravels; LU2 consisting of well-classified medium to coarse sands, asymmetry towards fine to coarse elements; and LU3 consisting of silty clays and clayey sands. Correlation of results assigns UG1 and LU3 to low hydrodynamics, GU2 and LU2 to medium hydrodynamics, and GU3 with LU1 to high hydrodynamics. A 3D filling model has been developed. This model shows that the volume of GU1-LU3 is estimated of 33,549,496 m3 , for GU2-LU2 is estimated of 18,352,728 m3 , and of GU3-LU1 of 7,687,875m3 . This study has important implications for the knowledge and characterization of lithological units, especially geomaterials.

Tetracycline removal from water by adsorption on geomaterial, activated carbon and clay adsorbents

Ait-Hamoudi Souhila, Hamdi Boualem, Brendlé Jocelyne

Ecological Chemistry and Engineering. S

2021

Vol. 28, nr 3

303--328

The use of antibiotics for breeding and for humans increased considerably in recent years, as a dietary supplement to enhance animal growth. This frequent use leads to the detection of residues in water and wastewater. Thus, the emergence of new strains of bacteria resistant to these antibiotics and, can lead to incurable diseases of livestock, and can lead to a possible transmission of these strains to humans. The purpose of this work is to develop new materials based on treated Maghnia clay, activated carbon, cement, and PVA polymer, named geomaterials. These materials were intended for the containment of hazardous wastes in landfills. The removal of tetracycline from aqueous solution was tested by adsorption onto synthesised geomaterials and their mineral constituents. Adsorption kinetics revealed that tetracycline was rapidly retained by GM and ATMa. This was confirmed by the relatively short equilibrium time of 30 min. The pseudo-second-order and intraparticle models well fitted the adsorption kinetic of the TC-adsorbent studied systems. It was noticed that the adsorption kinetic passes through several mechanisms, was demonstrated by the multi-linearity on the plot of qt against the square root of t. The adsorption capacity (Qa) of TC onto GM is pH-dependent. Indeed, Qa reaches a maximum value (Qa = 12.58 mg · g–1 at a very acidic pH of 2, then the adsorbed amount decreases to reach a minimum value at pH of 8, and for basic pHsQa increases up to 10 mg · g–1.