Sorption of the monoterpenes alpha-pinene and limonene to carbonaceous geosorbents including biochar

• The sorption of two monoterpenes, alpha pinene and limonene to the carbonaceous geosorbents graphite, bituminous coal, lignite coke, biochar and Pahokee peat was quantified. Polyethylene (PE) passive samplers were calibrated for the first time for these compounds by determining the PE-water partitioning coefficients and used as a tool to determine sorption to the carbonaceous geosorbents. Log KPE-water values were 3.49 +/- 0.58 for alpha pinene and 4.08 +/- 0.27 for limonene. The sorption of limonene to all materials was stronger than that for a pinene (differences of 0.2-13 log units between distribution coefficients for the monoterpenes). Placing K-d values in increasing order for a pinene gave biochar approximate to Pahokee peat approximate to bituminous coal approximate to lignite coke < graphite. For limonene the order was: Pahokee peat approximate to biochar approximate to bituminous coal < graphite approximate to lignite coke. Micropore (defined as pores <1.5 nm) and nanopore surface area (defined as pores 1.5 nm to 50 nm) normalised carbonaceous geosorbent-water distribution coefficients were also calculated. There was no clear correlation of these distribution coefficients with SA. Elemental composition was used to assess the degree of condensation (or alteration) of the carbonaceous geosorbents. The degree of carbonisation increased in the order; Pahokee peat < lignite coke < bituminous coal < biochar < graphite, however this was not correlated with an increase in the experimental distribution coefficients.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences (hsv//eng)

Nyckelord

Monoterpene

Biochar

Passive sampling

Sorption

Carbonaceous geosorbents

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