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Maximizing Ammonium Nitrogen Removal from Solution Using Different Zeolites
Author(s) -
Penn Chad J.,
Warren Jason G.,
Smith Savannah
Publication year - 2010
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2009.0324
Subject(s) - ammonium , nitrogen , zeolite , chemistry , environmental science , waste management , environmental chemistry , catalysis , engineering , organic chemistry
Zeolite minerals are ideal for removing ammonium nitrogen (NH 4 + –N) from animal wastes, leachates, and industrial effluents. The objectives of this study were to compare NH 4 + removal and kinetics among several commercially available zeolites under various conditions and determine if calorimetry could provide information regarding kinetics of NH 4 + removal. Ammonium sorption onto potassium (K) saturated zeolites was compared using synthetic vs. natural swine effluent and with either traditional batch‐shaken system or a “tea bag” approach in which zeolites were contained in a mesh sack and suspended in a solution of swine effluent. Ammonium sorption was measured at four retention times using a flow‐through system, and the resulting heat response was measured using isothermal calorimetry. Ammonium removal was not significantly different in synthetic vs. natural swine effluent. Ammonium removal was lower in batch‐stirred compared to batch‐shaken systems, suggesting that diffusion between particles was rate‐limiting in the former system. Flow‐through cells possessing contact times >100 s displayed greater NH 4 + sorption than batch systems, suggesting that maintaining high NH 4 + concentration in solution, removal of exchange products, and sufficient reaction time are critical to maximizing NH 4 + removal by zeolites. Within 100 s after NH 4 + addition, endothermic heat responses indicated that NH 4 + –K + exchange had peaked; this was followed by significant heat rate reduction for 50 min. This confirmed findings of an initial fast NH 4 + –K + exchange followed by a slower one and suggests the 100‐s period of rapid reaction is an indicator of the minimum flow through retention time required to optimize NH 4 + sorption to zeolites used in this study.