Evaluation of metal ion absorptive characteristics of three types of plastic sample bags used for precipitation sampling

Abstract

Simulated precipitation samples containing 16 metal ions were prepared at 4 pH values. Absorptive characteristics of polypropylene, polyethylene, and polyester/polyolefin sacks were evaluated at pH 3.5, 4.0, 4.5, and 5.0. Simulated precipitation was in contact with the sacks for 17 days, and subsamples were removed for chemical analysis at 3, 7, 10, 14, and 17 days after initial contact. All three types of plastic sacks absorbed Fe throughout the entire pH range. Polypropylene and polyethylene absorbed Pb throughout the entire pH range; polyester/polyolefin sacks absorbed Pb at pH 4.0 or greater. All plastic sacks also absorbed Cu, Mo, and V at pH 4.5 and 5.0. Leaching the plastic sacks with 0.7 percent HNO₃ did not result in 100 percent recovery of Cu, Fe, Pb, and V. These sacks would be suitable collection vessels for Ba, Be, Ca, Cd, Co, Li, Mg, Mn, Na, Sr and Zn in precipitation through the pH range of 3.5 to 5.0.

Key words:

• Precipitation
• Absorption
• Trace Metals