Porous graphene oxide–chitosan aerogel for tetracycline removal

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 × 10 3 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 k 1 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 Δ G implied that the adsorption was spontaneous and physisorption in nature. The positive Δ H 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.