Determination of Ammonia in Water Using Flow Injection Analysis with Automatic Pervaporation Enrichment

Abstract

An automated ammonia monitoring system has been developed by putting a pervaporation unit in an enrichment cycle used in flow injection analysis mode. In the proposed system, an enrichment cycle was equipped to enable the adjustment for the measuring range of ammonium by controlling the duration of the enrichment circulation. Therefore, the system was capable to determine ammonia in both the surface water with low ammonia concentration and the ammonia-rich wastewater with the linear dynamic range of 0.05–15 mg l⁻¹ and 15–50 mg l⁻¹, respectively. The relative standard deviations were less than 1.9% and the quantification limit is as low as 0.03 mg l⁻¹. The sampling frequency is 8–10 h⁻¹.

Keywords:

• Ammonia
• automatic
• enrichment cycle
• flow injection analysis
• pervaporation unit

The authors are grateful to Delin Environmental Instrument Co. Ltd., for financial and technological support.

Notes

X: the concentration of .

^a n = 9.

Difference = observed value (proposed)—expected value (conventional).

SW = surface water; WW = waste water.

NA: not available.

^a Based on a theoretical model.