Skip to main content
ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #30598
Title: NITRATE AND PHOSPHATE RECOVERY FROM ANION EXCHANGE RESINS

Author
item SCHNABEL R R - 1902-05-00

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/15/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: Fertilization practices designed to reduce nitrate losses to ground water are being recommended to and used by farmers. Methods for accurately measuring nitrate movement through soil are required to evaluate these practices. Ion-exchange resins which have the ability to selectively bind chemicals in water have recently been used to measure nitrate leached through soil over periods of months. However, the following questions must be answered before the procedure can be recommended. Does the resin completely remove nitrate from soil leachate, and also can that nitrate be extracted for analysis? The extraction step is critical to calculating nitrate movement to ground and surface waters. We evaluated three commonly used extractants. Of the three, one recovered over 95% of adsorbed nitrate. Because we found recovery of nitrate was affected by resin type and batch, and choice of extractant, we concluded it was necessary to test for nitrate recovery before initiating resin-based sampling and interpreting resin-based results.

Technical Abstract: The recovery of nitrate and phosphate from two anion exchange resins was determined. A general purpose and nitrate selective resin were extracted with KCl, acidified NH4Cl, and Na2SO4. The recovery of both nitrate and phosphate were significantly affected by the choice of resin and extractant. The combination of Na2SO4 extractant and nitrate selective resin resulted in less than half as much nitrate recovery as any other combination of resin and extractant. Consequently, if it is important to recover nitrate from the resins, Na2SO4 should not be used. Greater quantities of phosphate were recovered from the nitrate selective resin with all extractants. However, phosphate recovery was not significantly affected by choice of extractant. More rigorous extraction was required for the nitrate selective resin to achieve a level of nitrate recovery comparable to the general purpose resin. The nitrate selectivity also resulted in less phosphate being adsorbed from solutions high in nitrate. Finally, new batches of resin should be tested because differences between them can be significant.