Thermal Aging of Heteroatom-Substituted Keggin-Type Aluminum Oxo Polycation Solutions: Aggregation Behavior and Impacts on Humic Acid and Turbidity Removal

Keggin-type aluminum-oxo polycations are effective coagulating agents for wastewater treatment. Previous work demonstrated that heteroatom substitution in ε-Al13 polycation leads to the formation of ε-GaAl12 and ε-GeAl12 can enhance removal bacteria, DOC, turbidity from wastewater. Additional hydrolysis species creates larger Al30 improves coagulation performance, but this aspect has not been evaluated systems. In current study, ε-Al13, ε-GaAl12, was promoted through hydrothermal aging evaluate overall solution stability/behavior water treatment efficiency. Turbidity measurement aged indicated Ga-substituted Keggin remain stable solution, DLS studies greater diversity particle sizes within system. Thermogravimetric analyses metal hydroxide formed during indicate GaAl12 system behaves more like an amorphous Al(OH)3 phase, which higher solubility than other aluminum phases. Aging did significantly change % humic acid (HA) removal, as all solutions showed high efficiency at studied pH values. good ranges, with enhanced performance 5. The contain relatively oligomers, may contribute contaminant removal.