Publikacje

Abstract:

Chemical composition of sewage sludge ash (SSA) is significantly similar to the composition of coal fly ash which is a popular material used for the synthesis of zeolites. Zeolites. are crystalline aluminosilicates containing pores of molecular size. The project presents the results of the synthesis of zeolites from SSA. It is based on the zeolitization of SSA by the direct hydrothermal method and an indirect fusion followed by a hydrothermal method. SSA used in the study was obtained as a result of sewage sludge (SS) incineration in a laboratory furnace. The chemical compositions of SS and SSA were determined by using the X-ray fluorescence spectroscopy. The research included the identification of a phase composition of SSA after the process of zeolitization by the X-ray diffraction method, the structure of samples by the scanning electron microscopy and the cation exchange capacity by a method with the use of ammonium acetate. Depending on the method of zeolitization, different types of crystalline phases were obtained. The obtained zeolites were hydroxysodalite, hydroxycancrinite and zeolite X. Besides, it was stated that zeolitization by the indirect fusion method caused a positive increase of the cation exchange capacity. It was found that a better method for the synthesis of zeolites is the indirect fusion method than the direct hydrothermal method. These results show that the combustion of SS gives not only the recovery of energy but also waste which could be converted into a useful material. SSA after zeolitization can be potentially used for sorption of contaminants, for instance ammonium and heavy metals.

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THE EVALUATION OF THE POSSIBILITY OF MATERIAL RECOVERY FROM SEWAGE SLUDGE ASH BY ZEOLITIZATION