Textile waste-derived functional carbon materials for selective pharmaceutical pollutant removal

The physical and chemical attributes of functional carbon materials depend on the conditions of synthetic pyrolysis, which consequently influence pollutant removal efficacy. In this study, textile waste (e.g., denim waste)-derived functional carbon materials (DFCMs) were synthesized using CO 2 and N 2 as pyrolysis carrier gases, after which their surface characteristics were systematically examined. Comparative analysis revealed the formation of numerous C–H bonds in CO 2 -DFCM, whereas bonds of oxygen-containing functional groups and amine groups emerged in N 2 -DFCM. Furthermore, an assessment of the contact angle between DFCM and water molecules revealed a high contact angle of 94.6° for CO 2 -DFCM, whereas N 2 -DFCM exhibited a 69.8° contact angle. These findings demonstrate that CO 2 -DFCM is hydrophobic, whereas N 2 -DFCM is hydrophilic. Similarly, capillary strength analyses revealed that CO 2 -DFCM and N 2 -DFCM possess capillary forces of −8.41 × 10 6 N m −2 and 2.35 × 10 7 N m −2 , respectively. These surface disparities also manifested in varying antibiotic adsorption capacities, with CO 2 -DFCM exhibiting heightened removal rates for hydrophobic antibiotics such as sulfamethoxazole and acetaminophen, whereas N 2 -DFCM exhibited superior removal rates for tetracycline acid and oxytetracycline hydrochloride, antibiotics with hydrophilic properties. Collectively, the outcomes of our kinetic, isotherm, and hydrothermal dynamic modeling provide insights into the adsorption mechanisms of antibiotics onto DFCMs, revealing distinct mechanisms dependent on the antibiotic type. • Functional carbon materials were synthesized by pyrolyzing denim waste. • Different carrier gas conditions alter the surface properties of DFCMs. • The surface of CO 2 -DFCM exhibited greater hydrophobicity compared to N 2 -DFCM. • Antibiotics were selectively removed based on the surface properties of DFCMs. • The adsorption mechanisms varied according to the properties of each antibiotic.