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ARS Home » Southeast Area » Florence, South Carolina » Coastal Plain Soil, Water and Plant Conservation Research » Research » Publications at this Location » Publication #364464
Research Project: Improvement of Soil Management Practices and Manure Treatment/Handling Systems of the Southern Coastal Plain

Location: Coastal Plain Soil, Water and Plant Conservation Research

Title: Effect of the type of gas-permeable membrane in ammonia recovery from air

Author
item SOTO-HERRANZ, MARIA - University Of Valladolid
item SANCHEZ-BASCONES, MERCEDES - University Of Valladolid
item ANTOLIN, JUAN - University Of Valladolid
item CONDE-CID, DIEGO - University Of Valladolid
item Vanotti, Matias

Submitted to: Environments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/14/2019
Publication Date: 6/16/2019
Citation: Soto-Herranz, M., Sanchez-Bascones, M., Antolin, J.M., Conde-Cid, D., Vanotti, M.B. 2019. Effect of the type of gas-permeable membrane in ammonia recovery from air. Environments MDPI. 6:70. https://doi.org/10.3390/environments6060070.
DOI: https://doi.org/10.3390/environments6060070

Interpretive Summary: Animal production is one of the largest contributors to gaseous ammonia (NH3) emissions. Ammonia emissions contribute to ecosystem degradation when it is deposited on land or water with corresponding soil acidification and eutrophication of surface water bodies. A European Union LIFE project Ammonia Trapping (AT) was designed to recover gaseous ammonia from animal barns in Spain's farms. The main objective of the AT project was to reduce NH3 emissions from the atmosphere of swine and poultry farms by using gas-permeable membrane (GPM) technology. The NH3 present in the air passes through the wall of the GPM and is captured by an acid solution that circulates on the other side to form a fertilizing salt (ammonium sulfate). Targets in the AT project were a reduction in the NH3 concentration of 70 percent of or higher, and rates of ammonia trapping of 1.3 g N per square meter of membrane per day. The lack of studies about the efficiency of GPM materials with different characteristics to capture of NH3 from the air prompted this laboratory study to properly select GPM materials before a larger on-fam pilot evaluation, especially considering the cost difference of these membranes. The present study evaluated the effect of three different GPMs on the recovery of ammonia from the air. The GPMs were made of ePTFE (expanded polytetrafluoroethylene) polymer. The ammonia recovery yields were higher with the use of GPM of greater diameter and corresponding surface area, but they were not affected by the large differences in material density, porosity, air permeability, and wall thickness evaluated. A higher fluid velocity of the acidic solution significantly increased - approximately 3 times- the mass of NH3 recovered per unit of membrane surface area and time (N-flux), from 1.7 to 5.8 g N per square meter of membrane per day. Therefore, to optimize the effectiveness of a GPM system to capture gaseous ammonia, the velocity of the circulating acidic solution should be an important design consideration.

Technical Abstract: Animal production is one of the largest contributors to ammonia emissions. A project Ammonia Trapping was designed to recover gaseous ammonia from animal barns in Spain farms. Laboratory experiments were conducted to select type of membrane most suitable for gaseous ammonia trapping. Three types of gas-permeable membranes (GPM), all made of expanded polytetrafluoroethylene (ePTFE), but with different diameter (3.0 to 8.6 millimeters), polymer density (0.45 to 1.09), air permeability (2 to 40 Liters per min per square centimeter), and porosity (5.6 to 21.8 percent) were evaluated for their effectiveness to recover gas phase ammonia. The ammonia evolved from a synthetic solution (ammonium chloride + sodium bicarbonate + allythiourea), and an acidic solution (1 Normal sulfuric acid) was used as the ammonia trapping solution. Replicated tests were performed simultaneously during a period of 7 days with a constant flow of acid solution circulating through the lumen of tubular GPMs. The ammonia N (nitrogen) recovery yields were higher with the use of GPM of greater diameter and corresponding surface area, but they not affected by the large differences in material density, porosity, air permeability, and wall thickness evaluated. A higher fluid velocity of the acidic solution significantly increased - approximately 3 times- the mass of ammonia recovered per unit of membrane surface area and time (N-flux), from 1.7 to 5.8 mg N per square centimeter of membrane surface per day. Therefore, to optimize the effectiveness of GPM systems to capture gaseous ammonia, the appropriate velocity of the circulating acidic solution should be an important design consideration.