Estimating sorption rates of hydrophobic organic compounds in iron oxide and aluminosilicate clay-coated aquifer sands

被引:40
作者
Holmen, BA [1 ]
Gschwend, PM [1 ]
机构
[1] MIT,RALPH M PARSONS LAB,CAMBRIDGE,MA 02139
关键词
D O I
10.1021/es9601696
中图分类号
X [环境科学、安全科学];
学科分类号
08 ; 0830 ;
摘要
We hypothesized that retarded diffusion in coatings controls the rate of sorption of hydrophobic organic compounds (HOCs) on quartzitic aquifer sands. Microscopic examination of three sands was used to quantify the coating thicknesses. With measures of the coatings' organic contents and porosities, we predicted the relative sorption rates for (a) multiple HOCs on one sand end (b) one HOC with three sands. The predicted relative rates and equilibrium coefficients were assessed using observations of HOC transport through short sand columns operated at varying flow rates. We found that the column K-d values were always much less than predicted from K(oc)f(oc) or observed in batch tests. This suggests that diagenetically produced sorbents may include organic matter that is completely inaccessible for HOC sorption; procedures that disaggregate these sands could expose organic matter that does not sorb HOCs in the environment. Second, by modifying our retarded diffusion expectations with the inferred fraction of available organic carbon, f(avail), all observed sorption rates were consistent (within a factor of 4) with k(r) approximate to 0.001 D-aq/delta(2)(1 + r(sw)(coat)K(oc)f(oc)(coat)f(avail)), where k(r) is the desorption rate constant, D-aq is the HOC's aqueous diffusivity, delta is the coating thickness, r(sw)(coat) is the ratio of solids-to-water in the coatings, f(oc)(coat) is the organic carbon content of the coating solids, and all other factors affecting sorption rates (e.g., tortuosity) were set equal to 0.001. Since oxide coatings are ubiquitous in aquifer sands, the model described here should have wide applicability.
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页码:105 / 113
页数:9
相关论文
共 66 条
[21]   SIMULATING SOLUTE TRANSPORT USING LABORATORY-BASED SORPTION PARAMETERS [J].
HARMON, TC ;
SEMPRINI, L ;
ROBERTS, PV .
JOURNAL OF ENVIRONMENTAL ENGINEERING-ASCE, 1992, 118 (05) :666-689
[22]   COMPARISON OF INTRAPARTICLE SORPTION AND DESORPTION RATES FOR A HALOGENATED ALKENE IN A SANDY AQUIFER MATERIAL [J].
HARMON, TC ;
ROBERTS, PV .
ENVIRONMENTAL SCIENCE & TECHNOLOGY, 1994, 28 (09) :1650-1660
[23]   PREDICTION OF DIFFUSION-COEFFICIENTS FOR NONELECTROLYTES IN DILUTE AQUEOUS-SOLUTIONS [J].
HAYDUK, W ;
LAUDIE, H .
AICHE JOURNAL, 1974, 20 (03) :611-615
[24]  
HOLMEN BA, 1995, THESIS MIT
[25]   TRANSPORT OF ORGANIC-COMPOUNDS WITH SATURATED GROUNDWATER-FLOW - EXPERIMENTAL RESULTS [J].
HUTZLER, NJ ;
CRITTENDEN, JC ;
GIERKE, JS ;
JOHNSON, AS .
WATER RESOURCES RESEARCH, 1986, 22 (03) :285-295
[26]  
Jackson M. L., 1986, Methods of soil analysis. Part 1. Physical and mineralogical methods, P101
[27]   MECHANISMS OF DISSOLVED ORGANIC-CARBON ADSORPTION ON SOIL [J].
JARDINE, PM ;
WEBER, NL ;
MCCARTHY, JF .
SOIL SCIENCE SOCIETY OF AMERICA JOURNAL, 1989, 53 (05) :1378-1385
[28]   SEMIEMPIRICAL ESTIMATION OF SORPTION OF HYDROPHOBIC POLLUTANTS ON NATURAL SEDIMENTS AND SOILS [J].
KARICKHOFF, SW .
CHEMOSPHERE, 1981, 10 (08) :833-846
[29]   ORGANIC POLLUTANT SORPTION IN AQUATIC SYSTEMS [J].
KARICKHOFF, SW .
JOURNAL OF HYDRAULIC ENGINEERING, 1984, 110 (06) :707-735
[30]   SORPTION OF HYDROPHOBIC POLLUTANTS ON NATURAL SEDIMENTS [J].
KARICKHOFF, SW ;
BROWN, DS ;
SCOTT, TA .
WATER RESEARCH, 1979, 13 (03) :241-248