Recyclable 3D konjac glucomannan/graphene oxide aerogel loaded with ZIF-67 for comprehensive adsorption of methylene blue and methyl orange

To solve the problem that it is difficult to recycle the ZIF-67 in aqueous solution, a porous self-supporting material (KGM/GO) was prepared by using biomass KGM. And then ZIF-67 crystal was loaded onto KGM/GO solid substrate by in-situ growth method so that a novel KGM/GO/ZIF-67 composite aerogel was obtained. FT-IR and SEM characterization showed that ZIF-67 was successfully loaded on KGM/GO substrate by covalent bonding, and the adsorption site of composite aerogel surface was uniform. The N2 adsorption/desorption testing results showed that the porosity of composite aerogel changed from 86.48 % to 91.18 % after loading ZIF-67. It provides enough diffusion channel and active adsorption sites. Moreover, the as-prepared composite aerogel showed excellent adsorption ability to both methylene blue and methyl orange, and the maximum adsorption capacities were as high as 185.67 mg/g (pH = 8) and 130.2 mg/g (pH = 2), respectively. Noted that after five cycles, the adsorption capacity to methylene blue and methyl orange were still up to 174.4 mg/g and 118.3 mg/g, which exhibited high adsorption capacity and excellent reusability. Therefore, loading ZIF-67 on KGM/GO substrate can enhance the adsorption and recovery performance of ZIF-67. The method provides a new possibility for the treatment of complex dye-containing wastewater.