Cadmium removal using Rhassoul/alginate composite beads: isotherms, kinetics, and thermodynamic study

Cadmium is a threat to human health and the environment. Therefore, there is a need for efficient and sustainable adsorbents to remediate cadmium-contaminated water. This study explores the effectiveness of Rhassoul clay/alginate composite beads in adsorbing cadmium from aqueous solutions, a simple, efficient, and cost-effective water treatment method. Various physicochemical factors influencing the adsorption capacity of the Rhassoul/alginate hybrid composite beads were examined, including adsorbent dosage (0.5-4.0 g/L suspension), contact time (30-360 min), pH (2-7), initial Cd2+ concentration (20-200 mg/L), and temperature (25-40 degrees C). The results revealed an adsorption capacity of 20 mg/g for non-modified Rhassoul clay, while the Rhassoul/alginate composite beads exhibited a significantly higher maximum adsorption capacity of 105 mg/g. Thermodynamic parameters (triangle G degrees, triangle H degrees, and triangle S degrees) indicated the process was spontaneous and endothermic.