Adsorption of doripenem and meropenem antibiotics on activated carbon derived from snake fruit seeds: single-compound and binary mechanism via experiments and modelling

Abstract

The increasing presence of pharmaceutical contaminants in aquatic environments raises serious concerns regarding water quality and public health. In this study, activated carbon derived from snake fruit seeds was developed and applied for the adsorption of two β-lactam antibiotics, doripenem (DOR) and meropenem (MER), in both single and binary aqueous systems. The adsorbent was characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and nitrogen adsorption-desorption isotherms. The results confirmed the development of a rough and porous surface morphology, and a mesoporous network with high surface area (1260.61 m²/g), which are favorable for adsorption. Based on single experimental data, the maximum adsorption capacities are193 mg/g for DOR and 171 mg/g for MER. These performances were reduced when a second adsorbate (MER or DOR) is present in solution, reflecting a competition on the same adsorbent site. The model for binary solutions contains number of molecules per site (n₁, n₂) explaining the antagonist effect between both adsorbates when interacting for the same activated carbon receptor sites (ACRS). Comparatively, it was demonstrated that our adsorbent is an efficient material for various pharmaceuticals removal. In summary, the activated carbon indicated promising performance to remove various pharmaceuticals including MER and DOR.