Porous graphene oxide–chitosan aerogel for tetracycline removal

Abstract

Nanotechnology has brought new approaches for the treatment of antibiotics, which are potent pollutants to water. In this study, we reported that a porous graphene oxide–chitosan aerogel (PGO-CS) could be used as a recyclable adsorbent for tetracycline removal. PGO-CS adsorbed tetracycline with a capacity of around 1.47 × 103 mg g−1, ranking it among the most effective adsorbents for tetracycline. The adsorption equilibrium was well fitted to the Temkin model with a b value of 2.83 × 10−3 kJ mol−1. The adsorption kinetics was described by the pseudo-first-order model, giving a k1 value of −2.37 × 10−3 (1 min−1). The intraparticle model fitting suggested that the adsorption involved intraparticle diffusion and surface diffusion. In the thermodynamics investigation, the negative ΔG implied that the adsorption was spontaneous and physisorption in nature. The positive ΔH demonstrated that the adsorption process was endothermic and the adsorption was mainly driven by the increased randomness. Higher pH and ionic strength facilitated the adsorption significantly. In addition, PGO-CS was easily regenerated by washing with HCl aqueous solution.