This work aims to use a green, economical and efficient adsorbent to remove organic matter from Tunisian industrial wet phosphoric acid (WPA: 52% P₂O₅). For this purpose, a natural and abundant clay is extracted from the Douiret, Tataouine deposit in southern Tunisia. This clay is being tested for the first time as an adsorbent in WPA medium. The raw clay and purified clay are analysed using standard analytical techniques such as Fourier transform infrared spectroscopy, X-ray diffraction, and BET methods. The results show that the raw clay is a mixture of illite and kaolinite, with other mineral impurities, mainly quartz. Organic matter adsorption tests show that the purified clay exhibits greater effectiveness than raw clay. The parametric study with purified clay indicates that temperature, contact time, and clay dosage strongly influence organic matter adsorption. The highest adsorption occurs at 60 °C after 50 min, reaching 56% with 8 g of purified clay per kg of WPA. Among several recognised models, the pseudo-second-order kinetic model and the Sips isotherm model are the most suitable for modelling the experimental data. This study suggests that Douiret clay can be considered an effective, inexpensive and environmentally friendly adsorbent for eliminating organic matter in industrial phosphoric acid.

Three-quarters of the surface of our planet is covered by water. Nevertheless, these inexhaustible reservoirs like oceans are not suitable for drinking because it is salt water. This work deals with water desalination as a solution to the water scarcity problem. It presents a new process of solar distillation that naturally produces distilled water. The essential features of this process are summarized by the production of heat via electric resistor. In this work, the photovoltaic source is feeding the resistive load. The simulation work was elaborated under the real meteorological conditions of Gabes, a city in the south of Tunisia. In order to optimize the photovoltaic system efficiency, a maximum power point tracker that controls a DC–DC boost converter is used. The system was implemented and then tested on a sunny day under variable resistance combination. The simulation results show that increasing the number of panels increases the quantity of distilled water; on the other hand, the parallel association of resistances improves the time needed for the distillation of water.