Magnetic oxide nano-porous adsorbents: a highly efficient approach for acid Fuchsin removal from medical laboratory effluents via adsorption process

This study combines clay adsorption properties with magnetic iron oxide properties to create a composite magnetic adsorbent for removing Acid Fuchsin Dye (AFD) from laboratory effluents. The research focuses on characterizing clay minerals, particularly investigating interlayer spacing in smectites using FTIR, BET, and SEM with EDX elemental mapping. Synthesizing Magnetic Oxide Nano-Porous Clay (MONPC) approximately doubles the specific surface area (10.02 to 18.03 m 2 g −1 ) compared to Natural Clay. Using an adsorbent concentration of 0.1 g/L, MONPC completely removes AFD from initial dye solutions at a 400 mg/L concentration due to strong hydrogen bonding and Lewis interaction, as observed in the adsorption mechanism study. The Pseudo-Second-Order model accurately represents the chemisorption process of AFD, while the Freundlich isotherm model consistently fits the data better than the Langmuir model. Thermodynamic analysis confirms the exothermic and spontaneous nature of the adsorption process, with significant entropic changes at the solid–liquid interface. These findings suggest favorable enthalpy but unfavorable entropy for the adsorption of AFD onto MONPC. MONPC's high surface area and enhanced adsorption capacity hold tremendous potential as an effective adsorbent for removing AFD in wastewater treatment applications. Graphical abstract