Natural polymer konjac glucomannan mediated assembly of graphene oxide as versatile sponges for water pollution control

Three-dimensional network structure of konjac glucomannan/graphene oxide (KGM/GO) sponges was successfully prepared by ice template method. The KGM/GO sponges was rich in functional groups, negatively charged under pH 2 to 10. Batch adsorption experiment was conducted to investigate the adsorption performance of the as-prepared KGM/GO sponges for organic dye (malachite green (MG)) and radionuclide (uranium U(Ⅵ)). The results showed that the maximum adsorption capacities of KGM/GO sponges were 266.97, 189.96 mg/g for U(Ⅵ) and MG, respectively. Moreover, the KGM/GO sponges exhibited an excellent selectivity for capturing U(Ⅵ) in multi-ion system. The adsorption process was fitted better to pseudo-second order model, while adsorption isotherms for these pollutants were well matched up to Langmuir models. In addition, KGM/GO sponges can be easily separated from the aqueous solution and could be effectively reused for 5 times without obvious loss in adsorption performance. The advantages of eco-friendliness, low cost, simple preparation process, controllable shape and size, as well as high adsorption capacities for MG and U(Ⅵ), suggested that KGM/GO sponges promising in water pollution control.