Zeolitic material synthesised from fly ash: use as cationic exchanger

The potential use as a 'once through' cation exchanger of a zeolitic material (NaP1 zeolite as the main active component) synthesised from fly ash has been evaluated and compared with a commercial weak acid exchanger, Amberlite IRC-50. The cationic exchange has been tested for different cations present in sewage: NH4+ (urban sewage) and Pb2+, Zn2+ and Cr3+ (waste from electrolytic baths). The NH4+ retention capacity was higher in the zeolite (0.7 meq g(-1)) than in Amberlite IRC-50 (0.21 meq g(-1)). The retention capacities of metallic cations obtained for NaP1 zeolite (1.16 meq Pb2+ g(-1), 1.45 meq Zn2+ g(-1) and 1.57 meq Cr3+ g(-1)) were also higher than in Amberlite IRC-50 (0.32 meq Pb2+ g(-1), 0.25 meq Zn2+ g(-1) and 0.35 meq Cr3+ g(-1)). When solutions containing all the metallic cations were used, lower retention capacities were obtained for both exchangers. (C) 2002 Society of Chemical Industry.