Exploring the adsorption potential of Na2SiO3-activated porous carbon materials from waste bamboo biomass for ciprofloxacin rapid removal in wastewater

Abstract

Effective utilization of biomass waste has become a key focus in achieving a sustainable future, considering the substantial amount of waste generated globally. This study investigates the characterization and evaluation of Na2SiO3-activated carbon derived from moso bamboo at various temperatures (500–900 °C) and residence time periods (30, 90, and 120 mins at 900 °C) for ciprofloxacin removal in aqueous solutions at initial concentrations of 50–250 mg/L. The activated carbons were characterized using N2 adsorption isotherms, revealing a combined Type I and Type IV behavior. The specific surface area (SBET) and total pore volume increased with increasing activation temperature, ranging from 157.3 m2/g to 381.6 m2/g. Regarding residence time, the SBET followed the sequence: Na2SiO3-60 (381.6 m2/g) > Na2SiO3-90 (333.8 m2/g) > Na2SiO3-120 (323.6 m2/g) > Na2SiO3-30 (312.7 m2/g). XRD analysis indicated a distinct peak at 23°, corresponding to the (002) plane of amorphous carbon, while Raman spectroscopy confirmed the presence of the D band and G band, indicating an amorphous carbon structure (ID/IG > 1). The adsorption performance of ciprofloxacin (CIP) on the activated carbons was evaluated at 298 K. The highest CIP removal rate of 89.2% was achieved within one hour using Na2SiO3-900, followed by Na2SiO3-800, Na2SiO3-700, Na Na2SiO3-600, and Na2SiO3-500, consistent with the SBET trend. The Langmuir adsorption isotherm model provided the best fit for analyzing the adsorption process, indicating predominantly monolayer adsorption, while the Freundlich model was suitable for ACs with different residence times. The maximum adsorption capacity of CIP was recorded for Na2SiO3-30 AC (17.12 mg/g). In conclusion, the synthesized activated carbons show promising potential as adsorbents for ciprofloxacin removal from water.