High‐Efficiency Adsorption Performance of Cobalt Alginate/ Graphene Oxide Aerogel Prepared by Green Method for Methylene Blue

Abstract In this paper, cobalt alginate/graphene oxide (CA/GO) aerogel composites were prepared by wet spinning and vacuum freezing. The cobalt ion only ion‐pairs with the carboxyl ion in the alginate, and other groups such as hydroxyl were not combined with cobalt ions, generating free hydroxyl, and thus improving the adsorption performance and recyclability of the composite material. The adsorption properties of CA/GO aerogels gradually improved with the increase of pH. The maximum adsorption capacity of CA/GO aerogel at 298 K was 294.18 mg.g −1 , and the adsorption process of methylene blue (MB) on CA/GO aerogel conformed to Langmuir isotherm model and pseudo‐second‐order model. The adsorption of MB on CA/GO is mainly attributed to electrostatic attraction, hydrogen bonding and π‐π interaction. Thermodynamic analysis showed that the adsorption process was both spontaneous and exothermic. After the CA/GO aerogel was reused for 5 times, the removal rate reached as high as 80.256 %. Compared with other adsorbents, the prepared adsorbent was proven to be provided with good removal capacity for MB, and expected to be widely applied to the adsorption treatment of MB wastewater.