Preparation of C30 concrete and its adsorption performance for Cs(I)

The preparation of C30 concrete for a cavernous waste repository under construction in China and its Cs(I) adsorption performance were investigated. The mix ratio of C30 concrete was cement:sand:gravel:water = 1:1.87:3.05:0.55. Three characterization analyses showed that C30 concrete has a good crystal structure, a large specific surface area and the presence of many –OH, HCO3−, CO32−, SiO42− groups and other groups. Adsorption experiments showed that the adsorption equilibrium was reached within 4 h, and pH had little effect on adsorption; several ions (K+, Ca2+, Mg2+, Cl−, NO3−, and SO42−) inhibited adsorption. The adsorption was more in line with the pseudo-second-order kinetic model and the Langmuir isothermal model. Thermodynamic analysis indicates that adsorption is endothermic and stochastic.