COLUMN LEACHING EXPERIMENTS ON AMMONIUM CHARGED ZEOLITITE

Laboratory experiments were performed to evaluate the inorganic nitrogen leaching of NH4-charged zeolitite (chabazite-bearing). Two columns, filled with zeolitite enriched in ammonium by mixing with swine manure and NH4Cl solution, respectively, were flushed with synthetic rain water in saturated conditions. Ammonium content in the leachate solution of the first column was higher than that measured in the second column, but in both cases it represented less than 9% of the total exchangeable ammonium. A small amount of nitrate, deriving from the exchange method with manure, was also found in the first column. The quantity of ammonium remained in the zeolitite after leaching was determined via cation exchange with KCl. The results of this study suggest that the NH4-charged zeolitite is only little affected by nitrogen leaching by rainfall and could be safely used as soil conditioner for agricultural purposes.