University Of Tehran Press Pollution 2383-451X 12 1 2026 01 01 A Kinetic and Equilibrium Study of Heavy Metals Removal by Clay as Low Cost Adsorbent from Aqueous Solutions: Case of an Akjoujt clay from Mauritania 351 365 105158 10.22059/poll.2025.400874.3083 EN Cheikh Ahmed Babe Laboratory of Materials Sciences, Faculty of Sciences and Technology of Nouakchott, Mauritania, Nouakchott-Mauritania Laboratory of Spectroscopy, Molecular Modeling, Materials, Nanomaterials, Water and Environment, Materials for Environment Team, ENSAM, Mohammed V University in Rabat, Morocco Ousseynou M’bodj Laboratory of Materials Sciences, Faculty of Sciences and Technology of Nouakchott, Mauritania, Nouakchott-Mauritania Abdoulaye Demba N’diaye Unité de Recherche Eau, Pollution et Environnement, Département de Chimie, Faculté des Sciences et Technique, Université de Nouakchott, Nouakchott, Mauritanie Mohammed Ben Ali Laboratory of Spectroscopy, Molecular Modeling, Materials, Nanomaterials, Water and Environment, Materials for Environment Team, ENSAM, Mohammed V University in Rabat, Morocco Asmae El-Yahyaoui Laboratory of Spectroscopy, Molecular Modeling, Materials, Nanomaterials, Water and Environment, Materials for Environment Team, ENSAM, Mohammed V University in Rabat, Morocco Fouzia Allali Laboratory of Spectroscopy, Molecular Modeling, Materials, Nanomaterials, Water and Environment, Materials for Environment Team, ENSAM, Mohammed V University in Rabat, Morocco Mohamed Kankou Unité de Recherche Eau, Pollution et Environnement, Département de Chimie, Faculté des Sciences et Technique, Université de Nouakchott, Nouakchott, Mauritanie El Mostapha Lotfi Laboratory of Spectroscopy, Molecular Modeling, Materials, Nanomaterials, Water and Environment, Materials for Environment Team, ENSAM, Mohammed V University in Rabat, Morocco Journal Article 2025 08 17 The present research investigated the adsorption of Gold (Au(I)), Copper (Cu(II)) and Zinc (Zn(II)) ions from aqueous solution using a natural clay from Akjoujt region in Mauritania as an low cost adsorbent. The natural Akjoujt clay were characterized by several physical and chemical methods such as X-Ray fluorescence (XRF), X-ray diffraction (XRD), Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), BET surface Area, cation exchange capacity (CEC) and Thermal Gravimetric Analysis (TGA). The removal efficacy of the Akjoujt clay adsorbent for Au (I), Cu(II) and Zn(II ion was studied in batch mode as a function of contact time and temperature. Adsorption kinetics data were modelled using pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetics. The behaviour and the nature of Au (I), Cu (II) and Zn (II) adsorption were analysed by employing the Langmuir, and Freundlich isotherm models. The adsorption kinetics followed the PSO kinetics whereas the adsorption data fitted well with the Langmuir isotherm model. The adsorption capacities (qm) from the Langmuir isotherm for Au(I), Cu(II) and Zn(II) are found as 2.90, 7.93 and 6.45 mg/g respectively. The effectiveness of Akjoujt clay in the adsorption of the three metals from aqueous system was Cu(II) > Zn(II) > Au(I).  The thermodynamic calculations suggested the spontaneous nature (ΔG° < 0) of the adsorption process, along with the endothermic characteristics (ΔH° > 0) in all cases. These findings highlight the promising potential of natural clay Akjoujt for efficiently adsorbing Au(I), Cu(II) and Zn(II) from aqueous solutions. https://jpoll.ut.ac.ir/article_105158_d39e113eb84641ef7f6ed5ee2bfc14d7.pdf