Leaching is a diffusion-reaction phenomenon which takes place when concrete is exposed to poorly mineralized or acid water. Degradation consists in dissolution of calcium and hydroxide ions out of the matrix, which causes an increase in porosity and transport properties of surface concrete. Leaching is accelerated in neutral and acid solutions, and it may be coupled with the ingress of aggressive ions such as chloride, sulfate, magnesium. For this means, this study computed Ca2+ ion content in pore solution theoretically.

The phenomenon of leaching consists in the dissolution of solid calcium in cement hydrates when concrete is exposed to any aggressive solution. Calcium leaching is completely controlled by the thermodynamic equilibrium between cement hydrates and the porous solution. Thus, it might be described by considering the hydrates (C-S-H and aluminates) solubility evolution with pH. Nevertheless a simplifed model has been proposed considering only the different calcium phases of the hydrates. This study suggested definition of calcium leaching density with type of cement hydrate.

The adsorption of lithium ion onto zeolite was investigated depending on contact time, initial concentration, cation forms, pH, and adsorption isotherms by employing batch adsorption experiment. The zeolite was converted into different forms such K+, Na+, Mg2+, Ca2+, and Al3+. The zeolite had the higher adsorption capacity of lithium ion in K+ form followed by Na+, Ca2+, Mg2+, and Al3+ forms, which was in accordance with their elctronegativities. The lithium ion adsorption was explained using the Langmuir, Freundlich, and Dubinin-Radushkevich adsorption isotherms and kinetic models. Adsorption rate of lithium ion by zeolite modified in K+ form was controlled by pseudo-second-order and particle diffusion kinetic models. The maximum adsorption capacity obtained from Langmuir isotherm was 17.0 mg/g for zeolite modified in K+ form. The solution pH influenced significantly the lithium ions adsorption capacity and best results were obtained at pH 5-10.