UK fly ash-based zeolites as adsorbents for removal of heavy metals and ammonium from artificially polluted solutions

Fly ash (FA) from the Rugeley Power Station, West Midlands (England) was used in this study as starting material in zeolite synthesis at laboratory scale using NaOH and KOH solutions. Na-phillipsitc, hydroxysodalite and K-chabazite were synthetized from FA using the classic hydrothermal route. The FA-based zeolites (FAZs) were employed as heavy metal and ammonium adsorbents from aqueous solutions artificially polluted with selected metals and other contaminants. Finally, with the aim of testing possible applications of the FAZs in water decontamination, efficiency for heavy metal and ammonium uptake from synthetic solutions using batch reactions at room temperature was investigated. Important parameters such as zeolite dose (g) per effluent volume unit (ml) and reaction time were examined in order to understand the removal mechanisms involved. The efficiency of the FAZs shows that these FAZs may reach CECs appropriate for their application in industrial wastewater treatment. The heavy metal selectivity of Na-phillipsite was determined as Cu>Zn>Cr>Ni>Pb, and it also showed a high affinity for NH4+.