Fabrication of waste paper/graphene oxide three-dimensional aerogel with dual adsorption capacity toward methylene blue and ciprofloxacin

To effectively treat the pollutant in sewage, a new-type three-dimensional aerogel based on graphene oxide and waste paper was fabricated via simple mixing and freeze-drying processes. Therein, waste paper was activated in advance, and polyvinyl alcohol served as physical crosslinking agent. The results showed that the obtained aerogel with porous three-dimensional network structure exhibited good thermal stability. When it acted as adsorbent for treating organic dye (methylene blue) and antibiotic (ciprofloxacin), the adsorption process was explored. In single system, the pseudo-first-order and pseudo-second-order kinetic models were used to discuss the detail about the aerogel adsorbing pollutant. Moreover, the Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms and calculate the isotherm constants. Thermodynamic results stated that the adsorption of pollutant onto aerogel was feasible and spontaneous. In binary system, the adsorption capacity of methylene blue by aerogel increased, while the adsorption capacity of ciprofloxacin by aerogel declined. The pseudo-second-order kinetics was consistent with the adsorption of pollutant by aerogel in such binary system. This study would provide a new boulevard to develop environmental, low-cost and high-efficiency adsorbent for removing pollutant from wastewater. Graphical abstract