Chiang Mai Journal of Science

     Low-cost natural materials-mediated adsorbents for the removal of dye pollutants from water are gaining popularity over chemical adsorbents due to their eco-friendliness, widespread availability, and ease of manufacture. A CaO-derived from eggshell was used to alter the surface of zinc-manganese-ferrite (Zn_0.6Mn_0.4Fe₂O₄) nanoparticles by the post-precipitation method. The CaO/Zn_0.6Mn0.4Fe₂O₄ nanocomposite was studied using FT-IR , XRD and SEM, and utilized for the removal of Rhodamine B dye. The adsorption efficiency of 10 mg L^-1 RhB reached 75% at pH 4.0, 60 min of shaking, and 2.0 g L^-1 of adsorbent. The intra-particle diffusion process was a rate-limiting phase, and the results matched the pseudo-second-order kinetics model. Adsorption data were well-fitting by the Langmuir isotherm model, with R2=0.989, KL =0.232, and maximal monolayer capacity (qmax) of 30.7mg.g^-1.The Tempkin isotherm revealed that the lateral repulsive forces are non-significant. The D-R model revealed positive adsorption-free energy confirming an endothermic chemical adsorption process. The Fenton-like catalytic degradation showed a removal of 98% at 80 min and increased by increasing the TDS of the medium.