Preparation of highly porous carbon from sustainable α-cellulose for superior removal performance of tetracycline and sulfamethazine from water

Abstract

Hierarchical carbon materials with ultrahigh specific surface area and high porosity were synthesized by KOH activation from sustainable α-cellulose and employed as adsorbents to study adsorption performance of tetracycline (TC) and sulfamethazine (SMZ) from aqueous solutions. The physical and chemical properties of the as-prepared materials were characterized by SEM, TEM, FT-IR, XPS, Raman and a surface area analyzer. The obtained porous carbon exhibited a hierarchical pore structure, large BET specific surface area (3187.91 m² g⁻¹) and pore volume (1.781 cm³ g⁻¹) when the activation temperature reached 850 °C. The maximum adsorption capacities were 1072.86 and 786.18 mg g⁻¹ for TC and SMZ removal at 298 K, respectively. Moreover, TC and SMZ showed similar adsorption features, kinetic results could fit well using a pseudo-second-order model, intraparticle diffusion was not the rate-controlling step and adsorption isotherm results fit well with the Langmuir model. The adsorption capacities increased with contact time and adsorption temperature and, moreover, pH and external ionic species have a significant effect on adsorption efficiency. Thermodynamic studies implied that physisorption might dominate adsorption and the adsorption process is spontaneous and thermodynamically favorable. The results are of importance to indicate that the as-prepared porous carbon could be used as a low-cost and effective adsorbent in pharmaceutical wastewater treatment.