engleski

Geopolymer-zeolite composites for photocatalysis

Due to their similarity, geopolymers and zeolites can be classified in the same category of alkali- aluminosilicate materials. It can be said that the main difference and the key parameter for the formation of zeolite are the hydrothermal conditions: elevated temperature/pressure and the amount of available water. Therefore, geopolymers can be considered an amorphous form of zeolite or metastable zeolites. In this research, the possibility of using the so- called "two-step method" for obtaining zeolite through intermediate product of geopolymer was investigated. The main advantage of this route is simple structural manipulation that can be used in a wide range of applications such as the development of dielectric materials, membranes, adsorption and immobilization of heavy metals, building materials, etc. Another advantage of this method is the possibility of making the desired shape of the material by geopolymer synthesis route at atmospheric pressure and temperatures below 80 ℃, which results in the formation of amorphous alkali-aluminosilicate material. Then, in hydrothermal conditions, the surface of the resulting material can be reorganized into an ordered crystalline structure. Metakaolin under the commercial name Metamax (BASF) and various water glasses (Na, Na/K and K) manufactured by Vodní sklo were used to obtain the geopolymer. While in hydrothermal synthesis, the influence of alkali metal oxides and silicon dioxide on the formation of zeolite structures at constant temperature was studied. The obtained samples were characterized by SEM, XRD and FTIR technique.

Geopolymers, zeolites, photocatalysis

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