Adsorption properties of the pharmaceutical contaminant tamoxifen on calcined bone char

Abstract

In this study, calcined bone char was produced from waste bones and characterized by SEM-EDX and BET surface area analysis. The adsorption properties of tamoxifen, a cytotoxic cancer drug, by calcined bone char were investigated in batch experiments and the effects of adsorbent dose, pH, contact time, temperature, and initial concentration were evaluated. Calcined bone char exhibits a monolayer adsorption capacity of 98.30 mg/g for tamoxifen was achieved at an initial concentration of 40 mg/L, an adsorbent dose of 20 mg/50 mL, a temperature of 25 °C, and a pH of 7. The Langmuir model (R²: 0.9900) provided the best fit to the isothermal adsorption data and supported monolayer, homogeneous surface adsorption. The pseudo-second-order-kinetic model (R²: 0.9997) best described the adsorption kinetics, indicating that chemisorption was the dominant mechanism. Thermodynamic analysis revealed that the adsorption process was spontaneous, endothermic, and entropy-driven. These findings demonstrate that calcined bone char is a sustainable and effective adsorbent for the removal of pharmaceutical contaminants from aqueous solutions.