Utilization of Galvanic Sewage Sludge to Produce Alkali-Activated Materials
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Department of Inorganic and Analytical Chemistry, Rzeszow University of Technology, Aleja Powstańców Warszawy 6, 35-959 Rzeszów, Poland
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Elżbieta Sitarz-Palczak
Department of Inorganic and Analytical Chemistry, Rzeszow University of Technology, Aleja Powstańców Warszawy 6, 35-959 Rzeszów, Poland
J. Ecol. Eng. 2024; 25(4):305-313
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ABSTRACT
The development of civilization is causing an increase in the amount of industrial wastes, especially hazardous wastes. Among the methods of utilisation of this type of waste, the methods of stabilisation and solidification deserve attention, which enable the transformation of hazardous waste and the heavy metals it contains into an environmentally safe form, that is, immobilised. This paper proposes a method to stabilize and solidify galvanic sludge using geopolymerization reactions. The surface morphology was studied, and the chemical composition was analyzed using the SEM-EDS method. The presence of characteristic functional groups on the surface of the galvanic sludge and the geopolymer obtained on its basis was determined by FTIR spectroscopic analysis. Moreover, we evaluated of the recovery of selected heavy metals were performed on the basis of leaching tests. It was found that, as a consequence of geopolymerization of galvanic sludge, this hazardous waste is transformed in such a way that the heavy metals it contains, which occur in the form of soluble compounds are immobilised. In relation to the metals analyzed, reduction in solubility were obtained at a practical level of 100% for Zn and Mn, for the remaining metals, respectively, 94% for Cu and in the range of 40 to 90% for Pb. Analysis of the FTIR spectra showed that the ions of the metals studied were permanently immobilised in the aluminosilicate structure of the geopolymers obtained. This shows, that galvanic sewage sludge, as hazardous waste, is chemically transformed into inert waste that may be deposited in landfills.