Publications (2)1.25 Total impact
- Journal of Environmental Science and Health Part A 01/2012; · 1.25 Impact Factor
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ABSTRACT: Presently, there are several strategies for the utilisation of fly ash available but most of them are leading to low volume of fly ash usage in South Africa. The cost implications, especially those associated with transportation, make it logistically difficult for fly ash to compete with other traditional raw materials in various applications. Synthesis of zeolites from coal fly ash with specific focus such as applications in water treatment could act as a more value-added high technology utilisation of fly ash to overcome this barrier. Previous studies have shown that the quality of zeolites synthesized is a major determinant in the efficiency of toxic element removal from waste water. It is therefore necessary to optimize the zeolite synthesis process to obtain high purity zeolites with high surface area and cation exchange capacity. The present study optimized synthesis conditions used to prepare zeolite Na-P1 from South African fly ash for the purpose of removing trace elements from brine. The variables that were evaluated during the optimization process of zeolitsation were; hydrothermal treatment time (12 - 48 hours), temperature (100 - 160 o C) and addition of varying molar quantities of water during the hydrothermal treatment step (H2O:SiO2 molar ratio ranged between 0 - 0.49). The most pure phase was achieved when NaOH/Si2O molar ratio was 0.59 at an aging temperature of 47 o C for 48 hours and a hydrothermal treatment temperature of 140 o C for 48 hours. The molar ratio of chemical composition of the optimum synthesis matrix was 1 SiO2 : 0.36 Al2O3 : 0.59 NaOH : 0.49 H2O. The cation exchange capacity of the product was 4.11 meq/g.The optimized process of zeolite Na-P1 was efficient in removing a large percentage of B, V, As, Mn, Ni, Pb, Fe, Zn, Mo, Sr, Ba, Mg, Cd and Se from a brine concentrate resulting from water treatment via reverse osmosis.