Preparation of modified graphene oxide composite aerogel and its adsorption to antibiotics

The two-dimensional carbon material graphene oxide （GO） was modified by using quaternary ammonium cationic surfactant dodecyl dimethyl benzyl ammonium chloride （BKC） through π-π interaction to improve its dispersion and stability in aqueous solution. To further enhance the crosslinking effect， the modified GO composites （GB） was coated with polydopamine （PDA） in an alkaline solution. The gelatine/modified graphene oxide/polydopamine composite aerogel （GGB） using biomass material gelatin （Gel） as the skeleton material was prepared by sol-gel method and freeze-drying technique. The micro-morphology and structure of GGB composite aerogel were characterized by SEM， FTIR and XPS， etc. The GGB was used for the adsorption of levofloxacin hydrochloride （LEV） and the adsorption effects were investigated under different conditions such as pH values，contact time，reaction temperature，initial solution concentration，and dosage of adsorbent. Furthermore， the adsorption effects of GGB and composite unmodified graphene oxide aerogel （GGO） on LEV were compared. The results show that the GGB composite aerogel shows excellent adsorption capacity for the LEV， and the LEV adsorption capacity of GGB is increased more than 3 times than that of GGO. Moreover， the adsorption process is a spontaneous exothermic process and the experimental data of the adsorption process are more fitted to the Langmuir isotherm and the pseudo-second-order kinetic model， the theoretical maximum adsorption capacity of LEV on GGB is 476.42 mg/g. After 5 adsorption-desorption cycles， GGB maintained an equilibrium adsorption capacity for LEV exceeding 80 mg/g. It is indicated that the GGB exhibits significant promise as a highly efficient adsorbent for removing of LEV from wastewater.