Development of functional geopolymers for water purification, and construction purposes

This paper deals with the development of functional geopolymers based on local resources such as kaolinite and zeolitic tuff for construction of water storage containers and transporting channels. After reaction at 80 °C a geopolymer is formed having suitable mechanical properties for the purpose of water storage and high adsorption capacity, e.g. Cd, for water purification. The effect of water content on the mechanical performance and physical properties of synthesized geopolymers iwas evaluated. The results confirmed also that adding the optimum ratio of water is, 28% of clay fraction, which revealed to the geopolymeric mixture resulting in observable improvements of physical, mechanical, and adsorption properties of the geopolymeric products. Such gGeopolymeric products with showed compression strength around 18 MPa under dry conditions and 8 MPa under wet conditions are obtained. This sample with the highest compression strength, and density, shows the and maximum adsorption capacity toward cadmium among the products and precursors tested including the natural zeolitic tuff. These results mean that a more perfect geopolymerization, using optimum water contents, leads to a more closed and denser structure with more diffusion limitations toward adsorption of Cd(II) ions. Also, the The residual soluble salts in produced geopolymers weare markedly reduced remarkably by using this optimum water content.