Application of zeolitic material synthesised from fly ash to the decontamination of waste water and flue gas

Abstract

Zeolitic material was synthesised from¯y ash using two different conversion methodologies. The two conversion products obtained were: (a) impure zeolitic material obtained by direct conversion from different Spanish¯y ashes, and (b) a high purity 4A±X zeolite blend synthesised from the silica extracts obtained from the Meirama¯y ash (NW Spain). The zeolitic material was tested for potential application as an ion exchanger to decontaminate waters containing high concentrations of ammonium and heavy metals. Preliminary results show high cation uptake ef®ciencies (up to 4.7 meq g À1 ) which allowed fast decontamination of different types of industrial or acidic mine waste waters. The CO 2 , SO 2 and NH 3 sorption capacity of several zeolitic products was also determined and very promising results were obtained for the A4±X blend. Sorption capacity values of up to 74, 297, and 111 mg g À1 for CO 2 , SO 2 and NH 3 respectively were obtained for the zeolitic material synthesised from silica extracts from¯y ash and a high-aluminate waste water.

Ion exchange uptake of ammonium in wastewater from a Sewage Treatment Plant by zeolitic materials from fly ash

“…cation exchangers for of NH 4 + and heavy metal removal, as reported by different authors [15][16][17][18][19]. However, in most of these studies, application was exclusively tested on synthetic solutions of those ions prepared in laboratories.…”

Experimental study of mercury removal from exhaust gases

“…However, more interesting is its future possible application, as an adsorbent for various pollutants (including radioactive elements and heavy metals). It has been demonstrated that, manufacture of synthetic zeolites from CFA is a relatively straightforward procedure [18][19][20][21][22] and such materials have been found to be effective in the removal of various pollutants from different environments (water, soils, flue gases) [15,[23][24][25][26][27][28][29]. A comparison with natural zeolites shows that synthetic zeolites are better for the removal of mercury compounds, due to the consistent size of the channels and chambers, in contrast to the microstructure of natural zeolites sizes which can be variable and often associated with a number of lattice defects [30].…”

Removal of mixed heavy metal ions in wastewater by zeolite 4A and residual products from recycled coal fly ash

“…Owing to zeolite's structural characteristics and their adsorbent properties, they have been applied as chemical sieve, water softener and adsorbents [10][11][12]. Several researchers have studied the removal performance and selectivity sequence of heavy metal ions by natural zeolites (clinoptilolite and chabazite) [13][14][15][16][17][18][19][20] as well as synthetic zeolites [21][22][23][24]. Ouki and Kavannagh [15] studied the performance of natural zeolites (clinoptilolite and chabazite) on the treatment of mixed metal effluents (Pb 2+ , Cd 2+ , Cu 2+ , Zn 2+ , Cr 3+ , Ni 2+ and Co 2+ ; concentration: 1-30 mg l −1 ); however, there were no data about kinetic modeling of the process.…”