Selective adsorption behavior/mechanism of antibiotic contaminants on novel boron nitride bundles

The novel hexagonal boron nitride (BN) bundles, assembled by a plenty of BN fibers with high adsorption capacity and outstanding recyclability, were prepared easily as an efficient adsorbent for antibiotics. It is an excellent substitute for carbonaceous adsorbent to overcome the shortcoming in low adsorption capacity and poor recyclability. Its high surface area can reach up to 871.456 m² g^-1. The adsorption capacity and removal percentage to sulfadiazine (SDZ, 0.328 mmol g^-1, 82.192%), oxytetracycline (OTC, 0.202 mmol g^-1, 92.890%) and erythromycin (EM, 0.126 mmol g^-1, 90.140%) are superior compared with activated carbon and graphene nanoplatelets. It is interesting that BN bundles have a better adsorption to small molecules since huge molecules are easily restricted to enter the micropores, which was defined as micropore-filling effect. Moreover, the adsorption isotherms are well fitted by the Langmuir and Tempkin model, while pseudo-second-order model can better describe the adsorption kinetics. The adsorption mechanisms were deduced to be mainly π-π electron-donor-accepter interaction while electrostatic force and hydrophobic interaction played a significant role. The excellent reusability can be seen from the high removal efficiency after five recycles suggesting the BN bundles was a promising adsorbent for the efficient removal of antibiotics pollutants.