Removal of amoxicillin and paracetamol from water by carbon from peanuts skin waste material

Recent studies show that amoxicillin (AMX) and paracetamol (PRC) are among the most frequently prescribed drugs worldwide. As a result, these substances and their derivatives inevitably end up in water systems. This is a concern for human health and the environment in general. This research investigated the effectiveness of peanut skin in adsorbing AMX and PRC from water. Pristine (PPS), carbonised (CPS) and activated peanut skin (ACPS) were produced and characterised using SEM, EXD XRD and FTIR. The SEM images showed that the morphology of PPS is amorphous and has a high content of fatty acids. After carbonisation (CPS) and activation (ACPS), the samples had an improved surface, which is heterogeneous with well-developed pores and voids. The EDX shows that (C) and oxygen (O) are the main elements with traces of heteroatoms. The effect of initial concentration on adsorption showed that the adsorption increased gradually from 20–100 mg/L. It was observed that the removal of AMX gradually decreased with increasing temperature of the reaction mixture. This occurred with all adsorbents and confirmed that adsorption was exothermic. In contrast, the removal of PRC was enhanced by increasing the temperature of the reaction mixture. The trends for PRC confirm that the uptake is endothermic. The adsorption data were described by Freundlich and PSOM. The highest removal was observed at an initial pH of 6 and 8 for PRC and AMX respectively. The △G° values were negative, indicating that adsorption was favoured and feasible for AMX and PRC on all adsorbents. △S° was negative for all adsorbents, indicating that freedom at the solid-solution interface was restricted when adsorption reached equilibrium. FTIR analysis after adsorption showed that synergistic uptake mechanisms such as hydrogen bonding, Yoshida hydrogen bonding, and electrostatic and π-π interactions facilitated the adsorption of AMX and PRC. The adsorbents had adsorption capacities of 20.82, 32.76, and 35.98 mg/g for PRC and 12.36, 17.67, and 19.59 mg/g for AMX by PPS, CPS and ACPS, respectively.