Natural-based chalcopyrite nanoparticles as high-performance mineral adsorbents for organic dye removal in water

Sustainable and natural-based materials with high stability and efficiency for water pollutant removal are vital for advancing sustainable water treatment technologies. This study investigates the use of chalcopyrite mineral nanoparticles (CP NPs), derived from natural and sustainable sources, as efficient, recyclable, and scalable adsorbents for the removal of organic dyes from aqueous solutions. The CP nanoparticles have been thoroughly characterized using spectroscopic and microscopic techniques to determine their size, shape, elemental composition, and the oxidation states of the constituent elements. Due to their high surface area, unique electronic properties, and structural stability, chalcopyrite nanoparticles demonstrate promising potential in capturing and eliminating various dye pollutants from water. The BET analysis of CP NPs reveals a high surface area of 4.5 m² g⁻¹ with mesoporous structures and varying pore sizes (1.57–112.58 nm). We explored adsorption efficiencies using methylene blue dye, concentrations, and environmental conditions, showing that CP NPs offer high dye removal rates and rapid adsorption kinetics. Under the optimized conditions, a maximum removal efficiency of 99% was achieved using a pH of 8, a contact time of 40 minutes, a dye concentration of 10 mg L⁻¹, and an adsorbent dosage of 0.05 g/100 mL. The experimental data aligned most closely with the Freundlich isotherm model (R² = 0.991), suggesting that the adsorption occurred on a non-uniform, multilayered surface. The mechanism of the adsorption was elaborated. This work highlights the natural-based nanoparticles' applicability as cost-effective and sustainable adsorbents for water purification, advancing solutions to manage industrial dye pollutants and improve water quality in environmental systems.