Soil sorption of two nitramines derived from amine-based CO₂ capture

Area of Science:

• Environmental Chemistry
• Soil Science
• Chemical Engineering

Background:

• Nitramines are potential carcinogens formed from amines used in post-combustion CO2 capture (PCCC).
• Understanding nitramine environmental fate, particularly soil sorption, is crucial for risk assessment.
• Amines like monoethanolamine (MEA) and dimethylamine (DMA) are common in PCCC.

Purpose of the Study:

• To assess the soil sorption characteristics of monoethanolamine-nitramine (MEA-nitramine) and dimethylamine-nitramine (DMA-nitramine).
• To determine the influence of soil organic matter content and quality on nitramine sorption.
• To estimate environmental partitioning using organic carbon normalized soil-water distribution coefficients (KOC).

Main Methods:

• Batch experimental setup to measure nitramine loss from aqueous solutions.
• Liquid chromatography-tandem mass spectrometry (LC-MS/MS) for quantifying nitramine concentrations.
• Analysis of soil organic matter content and quality (Abs254 nm).

Main Results:

• Nitramine soil sorption is strongly dependent on soil organic matter content (r2 = 0.72-0.95, p < 0.05).
• MEA-nitramine sorption is further influenced by organic matter quality, linked to hydrogen bonding potential (r2 = 0.93, p < 0.05).
• Estimated KOC values are low, similar to simple amines, but significant retention is expected in organic-rich soils.

Conclusions:

• Soil organic matter is the primary factor controlling nitramine sorption.
• Forest topsoils are likely hotspots for nitramine accumulation due to high organic content.
• Data aids in predicting environmental concentrations of nitramines from PCCC emissions.