Sorption of sulfur gases by soils

Abstract

Gas Chromatographie studies showed that air-dry and moist soils have the capacity to sorb dimethyl sulfide (CH 3SCH 3), dimethyl disulfide (CH 3SSCH 3). carbonyl sulfide (COS) and carbon disulfide (CS 2), but do not sorb sulfur hexafluoride (SF 6). Moist soils sorb larger amounts of CH 3SCH 3. CH 3SSCH 3. COS or CS 2, than do air-dry soils, but the capacity of moist (or air-dry) soils for Sorption of these gases is much smaller than their capacity for sorption of H 2S. SO 2 or CH 3SH. The ability of moist soils to sorb COS is considerably greater than their ability to sorb CH 3SCH 3, CH 3SSCH 3 or CS 2. and sorption of COS by moist soils is accompanied by release of small amounts of CS 2. Experiments with sterilized (autoclaved) soils indicated that soil microorganisms are partly responsible for the sorption of CH 3SCH 3. CH 3SSCH 3. COS and CS 2 by moist soils. Support for this conclusion was obtained from experiments showing that the rate of sorption of these gases by moist soils increases with time. The work reported provides further evidence that soil is an important natural sink for gaseous atmospheric pollutants, but indicates that soils have little, if any, potential value for removal of CH 3SCH 3. CH 3SSCH 3. COS or CS 2, from industrial emissions polluted by these gases. The finding that soils have no capacity for sorption of SF 6 is significant in relation to use of this gas as a tracer for atmospheric research and as an internal standard for gas Chromatographie studies of evolution and sorption of gases by soils.