Speaker
Description
Zeolites are hydrated aluminosilicate minerals with a three-dimensional open structure consisting of aluminium and silicon tetrahedra linked by shared oxygen atoms. Due to this structure, zeolites are characterized by high specific surface and cations exchange capacity making them very useful in environmental pollution remediation. Literature data have documented the synthesis of zeolite using many raw materials including wastes. In this work, fly ash, a waste product of coal combustion in thermoelectric power plants, red mud, a waste produced by the caustic leaching process to extract aluminum from bauxite, volcanic ash deposited on city ground and therefore classified as waste (European Waste Catalogue - EWC) were successful used to form zeolite. The pre-fused hydrothermal aging was compared with ultrasonic pre-treatment as well as short time ultrasonic process. The results indicated that the hydrothermal process determined the zeolite synthesis by a double steps mechanism characterized by geopolymers formation and following newly-minerals crystallization whereas ultrasonic pre-treatment improved zeolite formation at a lower aging temperature. The synthesis process through ultrasonic treatment alone for short time, showed instead the effectiveness of sonication energy in the formation of more stable zeolites over time by precipitation mechanism.
The synthetic products showed good efficiency in both organic and inorganic remediation of soil and water pollutants.
Keywords: wastes, zeolite, synthesis processes, environmental pollution
| Speaker Country | Italy |
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