Screening Key Factors in the Preparation of Alkaline-Based Adsorbents for Amoxicillin Removal Using Design of Experiments

Pharmaceutical contaminants, such as amoxicillin, are persistent pollutants in wastewater and resist conventional treatment methods, posing environmental challenges. This study explores glycerol pitch, a biodiesel by-product, as a sustainable precursor for synthesizing polymerized adsorbents. Sodium hydroxide (NaOH), potassium hydroxide (KOH), and lithium hydroxide (LiOH) were evaluated as catalysts for glycerol polymerization, with NaOH-based adsorbents demonstrating the highest amoxicillin removal efficiency. To identify the key factors influencing adsorption performance, a two-factorial experimental design was employed, investigating polymerization temperature, polymerization time, alkali concentration, activation temperature, and activation time. A total of 32 experimental runs confirmed calcination temperature and time as the most significant parameters affecting amoxicillin removal, achieving efficiencies of up to 14.43%. These findings validate the critical parameters for adsorbent preparation, forming the basis for subsequent optimization using response surface methodology (RSM). The study underscores the potential of NaOH-catalyzed glycerol-derived adsorbents as cost-effective and sustainable solutions for pharmaceutical wastewater treatment, contributing to waste valorization and environmental sustainability.