CTAB-activated Carbon from Peanut Husks for the Removal of Antibiotics and Antibiotic-resistant Bacteria from Water

Peanut husk was used to prepare biochar (PHC) for water treatment. The biochar was modified with cetyltrimethylammonium bromide, CTAB (PHC-CTAB). PHC and PHC-CTAB were used to remove tetracycline (TET), amoxicillin (AMX) and antibiotics-resistant bacteria Escherichia coli from water. The surface properties of the adsorbents were identified using Fourier Transform Infrared (FTIR) spectroscopy, X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Elemental Dispersive X-ray technique (EDX), which confirmed the successful incorporation of CTAB into the biochar. The presence of CTAB resulted in increased adsorption capacities for the antibiotics. For tetracycline and amoxicillin, PHC-CTAB showed maximum adsorption capacities of 272 mg/g and 305 mg/g, respectively, whereas PHC had maximum adsorption capacities of 71.8 and 284 mg/g for TET and AMX. The mechanism was studied using adsorption kinetic models, with the results establishing that the adsorption proceeded mainly via physisorption for TET and chemisorption for AMX. PHC-CTAB resulted in the permanent deactivation of antibiotics-resistant Escherichia coli strain E11 ( ARE ) with 1.5 × 10 8 cfu/mL removed in 60 min, while PHC had only a temporary effect. When the toxicities of the adsorbents were tested on Lemna minor (duckweed), the results revealed that neither PHC nor PHC-CTAB had any toxic effects on the plant since the adsorbents did not prevent the duckweed from growing. In conclusion, PHC and PHC-CTAB are efficient adsorbents for removing antibiotics and antibiotic-resistant bacteria from water. Highlights • Peanut husk biochar (PHC) and CTAB-modified peanut husk biochar (PHC-CTAB) were tested. • The two adsorbents removed antibiotics and antibiotic-resistant bacteria. • PHC-CTAB provided the highest removal efficiency for tetracycline and amoxicillin. • Adsorption capacities of PHC-CTAB for tetracycline and amoxicillin were 272 and 305 mg/g. • PHC-CTAB had a permanent bactericidal effect on antibiotics-resistant Escherichia coli strain E11.