The Abu Tartur Plateau in the Western Desert of Egypt hosts the largest phosphate mining operation in the Middle East. Mining activities in this area generate several million tons annually of overburden waste materials, including carbonate, black shale, siltstone, glauconite, and sandstone. In the present study, phosphatic dolomite (PD) and black shale were collected from these mining wastes. Phosphatic dolomite, along with sodalite-based phosphatic dolomite (SBPD) synthesized from calcined phosphatic dolomite (CPD) and black shale, were evaluated as low-cost adsorbents for the removal of heavy metals (Pb²⁺, Cu²⁺, and Cd²⁺) from synthetic wastewater. Heavy metal contamination, particularly by Cd, Pb, and Cu, represents a major global environmental challenge. Among the available remediation techniques, adsorption is widely considered one of the most effective approaches due to its environmental sustainability, economic feasibility, and operational simplicity. The materials (PD, CPD, and SBPD) were characterized by using X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and BET surface
area. Key adsorption parameters—including adsorbent dosage, pH, initial metal concentration,
and contact time—were systematically investigated for Pb²⁺, Cu²⁺, and Cd²⁺ removal. The optimal
adsorption performance for SBPD was achieved using a dosage of 0.2 g for Pb²⁺ and Cd²⁺, whereas PD showed optimal removal efficiencies at 0.3 g for Pb²⁺ and 0.6 g for Cu²⁺. Both adsorbents exhibited a preferential removal order of Pb²⁺ > Cu²⁺ > Cd²⁺. Kinetic and isotherm models were applied to interpret the adsorption mechanisms. The results of the present study confirm that sodalite based phosphatic dolomite (SBPD) exhibited higher metal removal efficiency than unmodified phosphatic dolomite (PD).