Three-dimensional graded porous structure and compressible KGM-GO/CS/SA composite aerogel spheres for efficient adsorption of antibiotics

The abuse of antibiotics led to significant environmental pollution through persistent residues in water bodies, posing severe risks to both ecological systems and human health. Addressing this issue, recent studies highlighted the potential of carbonaceous materials as effective adsorbents for removing antibiotics from water. Despite the proven potential of various carbonaceous materials in water purification, the application of three-dimensional porous microspherical aerogels as adsorbents presented a promising yet comparatively less discussed avenue in the quest for efficient antibiotic removal from aquatic environments.This work introduced a novel KGM-GO/CS/SA composite aerogel sphere, developed via a simple sol–gel and dripping method, using konjac glucomannan (KGM) as a cross-linking agent. We extensively analyzed its adsorption efficiency against common antibiotics such as tetracycline (TC), ofloxacin (OFL), and sulfadiazine (SDZ), revealing its rapid adsorption kinetics and high capacity. The aerogel's micro-morphology, characterized by a graded porous structure with abundant microporous channels and a low bulk density of 21.2 mg/cm3, along with its enhanced mechanical properties and thermal stability due to KGM cross-linking, signified its potential as a robust adsorbent. The surface functional groups facilitated diverse interaction mechanisms, including electrostatic attraction, hydrogen bonding, and π-π interactions, contributing to the adsorbent's high performance. Furthermore, the surface charge of the aerogel varied with pH, enhancing its electrostatic adsorption capabilities. The adsorption behavior was best described by the quasi-second-order and Langmuir models, with maximum capacities of 427.63 mg/g for OFL, 374.35 mg/g for TC, and 231.09 mg/g for SDZ, thereby offering a promising solution for antibiotic pollution remediation and illustrating the utility of carbon-based aerogel microspheres in environmental applications.