Adsorption of metronidazole pharmaceutical active substance from aqueous solutions

This thesis aimed to evaluate the effectiveness of the adsorption method in removing metronidazole—a commonly detected pharmaceutical contaminant in aquatic environments. The study also sought to compare the performance of different adsorbents and identify the most suitable material for removal efficiency. Initially, five different adsorbents (Activated Carbon, Amberlite IRA-67, Amberlite A-21, Amberlite XAD-4, and Amberlite XAD-1180N) were tested. Adsorbents with low removal efficiency and long equilibrium times were excluded. Detailed experiments were conducted using Activated Carbon and Amberlite XAD-1180N, which demonstrated superior performance. Adsorption kinetics, isotherm models (Langmuir, Temkin), and thermodynamic parameters were examined. Activated Carbon achieved a removal efficiency of 87.2% and showed excellent fit to the Langmuir isotherm model (qₘ = 78.62 mg/g; R² = 0.998). Amberlite XAD-1180N reached equilibrium within 75 minutes and achieved 81.3% removal. The adsorption processes for both adsorbents were exothermic (ΔH° < 0) and spontaneous in nature (ΔG° > 0). While Activated Carbon exhibited high adsorption capacity, Amberlite XAD-1180N was more efficient in terms of contact time. These findings indicate that adsorption is an effective and sustainable method for removing persistent pharmaceutical compounds such as metronidazole. In this context, the study contributes to the development of sustainable and innovative wastewater treatment technologies for the removal of persistent pharmaceutical compounds.