Developing a New System Based on Membranes for Ammonia Recovery from the Atmosphere: Effect of Operation Time and Manure Temperature

Abstract

Ammonia (NH3) is a significant air pollutant with major environmental and health impacts, largely attributed to agriculture. Pig production is a major contributor, accounting for 25% of livestock NH3 emissions. This study developed a new system based on gas-permeable membranes (GPM) technology for NH3 recovery from the atmosphere obtaining a solution of ammonium sulfate as the resulting fertilizer product. Various experimental configurations were evaluated in the novel system using a synthetic NH3-emitting solution. The optimal arrangement was a GPM system with recirculation of the generated NH3 and without recirculation of the acidic trapping solution, yielding a nitrogen (N) recovery rate of up to 237 g m−2 d−1. Subsequent tests using pig manure (PM) at varying durations achieved rates of up to 73 g m−2 d−1, representing a four-fold increase in N capture efficiency compared to previous research. The influence of manure temperature on NH3 emission and capture were analyzed, simulating the possible differences between seasons (summer and winter), and revealing higher N recovery rates at elevated temperatures. At 21.5 °C, the recovery rate was 7.7 g m−2 d−1, while increased temperatures of 38.8 °C and 49.3 °C yielded rates of 15.9 and 27.2 g m−2 d−1, respectively.