Physico-chemical, mineralogical and structural characterization of a clay of Tanout (Zinder-Niger)

Abstract

The objective of this study is to identify the different mineral phases, the structural and textural properties of natural clay of Tanout in Zinder region (Niger) in order to have mineralogical data allowing its valuation. The methodology is based on a physicochemical characterization by coupling several analysis techniques (preliminary analyses, X-ray fluorescence, X-ray diffraction, thermos- gravimetric analysis, scanning electron microscopy, Brunauer-Emmett-Teller by adsorption of N2 at 77 K). The results from these analyzes show that this clay has a low humidity rate, a low density, a slightly neutral pH in an aqueous medium and a high cation exchange capacity and is mainly composed of SiO2 (68.1%), Al2O3 (17.02%) and Fe2O3 (7.6%) with trace elements, the most important of which are: Zr (4150.6 ppm), Sr (470 ppm), Cu (380.2 ppm) and V (320ppm). It essentially consists of Kaolinite and Montmorillonite with impurities such as quartz and microclines. It has a specific surface of 441.1 m2.g-1 and 2288 m2.g-1 calculated according to the BET and Langmuir methods respectively, with porous volume varying from 0.0157 to 0.2597 cm3.g-1 and of pore size which varies from 1.847 to 6.182 nm calculated according to the methods (Barrett-Joyner-Halenda, Dubinin-Radushkevich, Dubinin-A, Horvath-Kawazoe and Saito-Foley). This clay has an important degree of crystallinity. These characteristics make it a potential material that can be used in water pollution control.