Vol. 7, Issue 12, Part A (2025)

Background & Problem Statement: Emerging contaminants, particularly antibiotics, have emerged as significant environmental pollutants due to their widespread use and persistence in aquatic systems. Amoxicillin, a broad-spectrum β-lactam antibiotic, is frequently detected in wastewater and surface water, posing risks to aquatic ecosystems and human health. Conventional wastewater treatment methods fail to completely remove antibiotics, necessitating alternative approaches such as the adsorption method.

Methodology: This study investigates the adsorption of Amoxicillin onto Spirogyra biomass under various conditions, including pH (3-9), contact time (0-180 minutes), initial Amoxicillin concentration (10-100 mg/L), and temperature (25 °C, 35 °C, 45 °C). Batch adsorption experiments were conducted, and the data were analyzed using kinetic and thermodynamic models. Thermodynamic parameters, including Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°), were calculated to assess the feasibility of the adsorption process.

Key Findings: The maximum adsorption capacity of Spirogyra biomass for Amoxicillin was 21.68 mg g⁻¹, with optimal adsorption observed at pH 6.0. Adsorption followed the pseudo-second-order kinetic model, indicating chemisorption. The Langmuir model provided the best fit for equilibrium data, confirming monolayer adsorption. Thermodynamic analysis revealed that adsorption was spontaneous, endothermic, and associated with increased randomness at the solid-liquid interface.

Conclusion: Spirogyra biomass proved to be an efficient, eco-friendly biosorbent for Amoxicillin removal from aqueous solutions. The adsorption process was favourable at higher temperatures, suggesting potential applications in wastewater treatment. These findings contribute to the development of sustainable strategies for mitigating antibiotic contamination in water bodies.