In-situ reduced graphene oxide/geopolymer composites for efficient Cs+ immobilization

In order to improve the Cs + immobilization performance of geopolymer, in-situ reduced graphene oxide (rGO) reinforced geopolymer composites (rGO/GP) were prepared and they were further high-temperature treated to get rGO/pollucite composites. Effect of rGO addition on the thermal & mechanical properties and Cs immobilization were explored. When rGO content is 0.0125%, compressive strength of the rGO/GP composite reaches the maximum value. With the rGO content further increasing, the strength of rGO/GP shows a downward trend. DSC results show that the addition of rGO can increase the pollucite formation temperature. The presence of rGO also shows an important influence on the Cs + immobilization of geopolymer. Compared with pure geopolymer, Cs immobilization rate of composite with 0.0125% rGO content increases by 11.5%. For the composites treated at 1000 degrees C, all the samples show high immobilization rate for Cs, which are higher than 99.5%, due to pollucite formation in all the composites.