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United States Department of Agriculture

Agricultural Research Service

Boron Adsorption Data
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The boron adsorption data and model fits presented in this data base are described in the research paper entitled Modeling Boron Adsorption Isotherms And Envelopes Using The Constant Capacitance Model by S. Goldberg published in Vadose Zone Journal 3:676-680 (2004). The objectives of this study were to determine B adsorption isotherms and envelopes on a variety of soils having a range of soil chemical characteristics and to test the ability of the constant capacitance model to simultaneously describe B adsorption behavior as a function of both solution B concentration and solution pH. Detailed experimental and modeling methods used to obtain the adsorption data and model fits are provided in this publication. A summary will be provided below.
Boron adsorption was investigated on 23 surface and subsurface soil samples from 21 soil series belonging to six different soil orders. The soils were chosen from the Salinity Laboratory soil library to provide a range of soil chemical characteristics (see Table 1).
Boron adsorption isotherms (amount adsorbed as a function of equilibrium solution B concentration) and envelopes (amount adsorbed as a function of solution pH at a fixed total concentration) for the soils were determined in batch systems. Five grams of soil were equilibrated with 25 mL of a 0.1 M NaCl background electrolyte solution on a shaker for 20 h. The equilibrating solution contained 0, 0.0925, 0.185, 0.463, 0.925, 1.39, 2.31, 4.63, 9.25, 13.9, 18.5, or 23.1 mmol/L-1 B for isotherms and 0.463 mmol/L -1 B for envelopes. For the envelopes, pH was adjusted to pH 3-10 using additions of 1 M HCl or 1 M NaOH. After reaction, the samples were centrifuged, decanted, analyzed for pH, filtered, and analyzed for B concentration using inductively coupled plasma emission spectrometry.
Explanation of the application of the constant capacitance model to describe B adsorption isotherms and envelopes is provided in the above publication and references cited therein. The computer program FITEQL 3.2 (Herbelin and Westall, 1996) containing the constant capacitance model of adsorption was used to fit surface complexation constants to the experimental B adsorption envelope and isotherm data simultaneously. Initial input parameter values were capacitance: C = 1.06 F/m-2 and surface site density: Ns = 2.31 sites/nm-2 as in previous modeling studies of B adsorption using the constant capacitance model (Goldberg et al., 2000).
The model was fit simultaneously to the B adsorption isotherms and envelopes of all soil samples optimizing three surface complexation constants: logKB-(int) for B adsorption, logK+(int) for protonation, and logK-(int) for dissociation. Table 2 provides values of the optimized surface complexation constants. The ability of the constant capacitance model to describe B adsorption isotherms and envelopes simultaneously is indicated in the attached files.
 
REFERENCES
Goldberg, S., S.M. Lesch, and D.L. Suarez. 2000. Predicting boron adsorption by soils using soil chemical parameters in the constant capacitance model. Soil Sci. Soc. Am. J. 64:1356-1363.

Herbelin, A.L., and J.C. Westall. 1996. FITEQL: A computer program for determination of chemical equilibrium constants from experimental data. Rep. 96-01, Version 3.2, Dep. Of Chemistry, Oregon State Univ., Corvallis.
 
Table 1. Classifications and chemical characteristics of soils
Soil series
Depth
pH
CEC
S
IOC
OC
Fe
Al
cm
 
mmolc/kg-1
km2/kg-1
g/kg-1
g/kg-1
g/kg-1
g/kg-1
Altamont (fine, smectitic, thermic Aridic Haploxerert) 0-23 6.58 179 0.109 0.114 30.8 9.18 0.878
Arlington (coarse-loamy, mixed thermic Haplic Durixeralf) 0-25 7.38 107 0.0611 0.301 4.70 8.18 0.482
Avon (fine, smectitic, mesic, calcic Pachic Argixeroll) 0-15 6.46 183 0.0601 0.083 30.8 4.33 0.779
Bonsall (fine, smectitic, thermic Natric Palexeralf) 0-25 6.25 53.9 0.0329 0.134 4.87 9.32 0.446
Diablo (fine, smectitic, thermic Aridic Haploxerert) 0-15
0-15
7.00
7.11
301
234
0.194
0.131
0.264
2.20
19.8
28.3
7.13
5.79
1.02
0.844
Fallbrook (fine-loamy, mixed, thermic Typic Haploxeralf) 25-51 7.09 78.0 0.0285 0.240 3.11 4.92 0.212
Fiander (fine-silty, mixed, mesic Typic Natraquoll) 0-15 9.13 248 0.0925 6.90 4.00 9.24 1.06
Haines (coarse-silty, mixed, calcareous, mesic Typic Haplaquept) 20 8.20 80.4 0.0595 15.8 14.9 1.74 0.183
Hanford (coarse-loamy, mixed, nonacid, thermic Typic Xerorthent) 0-10 7.24 111 0.0289 10.1 28.7 6.60 0.347
Hesperia (coarse-loamy, mixed, nonacid, thermic Xeric Torriorthent) 0-7.6 6.52 44.6 0.0309 0.0178 4.88 3.20 0.338
Holtville (clayey over loamy, smectitic, mixed, calcareous, hyperthermic Typic Torrifluvent) 61-76 8.01 57.5 0.0430 16.4 2.10 4.86 0.269
Imperial (fine, smectitic, calcareous, hyperthermic Vertic Torrifluvent) 15-46 7.55 198 0.106 17.9 4.50 7.01 0.528
Nohili (very-fine, smectitic, calcareous, isohyperthermic Cumulic Endoaquoll) 0-23 7.25 467 0.286 2.70 21.3 49.0 3.66
Pachappa (coarse-loamy, mixed, thermic Mollic Haploxeralf) 0-25
25-51
7.18
6.96
38.6
52.1
0.0363
0.0410
0.0258
0.0138
3.77
1.09
7.64
7.16
0.670
0.384
Porterville (fine, smectitic, thermic Aridic Haploxerert) 0-7.6 6.62 203 0.172 0.0385 9.36 10.7 0.902
Reagan (fine-silty, mixed, thermic Ustic Haplocalcid) Surface 7.36 97.8 0.0588 18.3 10.1 4.58 0.450
Ryepatch (very-fine, smectitic, calcareous, mesic Vertic Endoaquoll) 0-15 7.12 385 0.213 2.50 32.4 2.59 0.924
Sebree (fine-silty, mixed, mesic Xerollic Nadurargid) 0-13 5.80 27.1 0.0212 0.00630 2.19 6.00 0.459
Wasco (coarse-loamy, mixed, nonacid, thermic Typic Torriorthent) 0-5.1 5.61 71.2 0.0559 0.00900 4.69 2.44 0.422
Wyo (fine-loamy, mixed, thermic Mollic Haploxeralf)   6.35 155 0.0782 0.0138 19.9 9.48 0.890
Yolo (fine-silty, mixed, nonacid, thermic Typic Xerorthent) 0-15 7.58 177 0.0730 0.235 11.5 15.6 1.30
Experimental methods are described in Goldberg et al. (2000).
 
Table 2. Constant capacitance model surface complexation constants
Soil Series
 
Depth
LogKB-
LogK+
LogK-
cm
 
 
 
Altamont clay loam 0-23 -6.53 5.32 -9.16
Arlington loam 0-25 -8.03 7.00 -11.07
Avon silt loam 0-15 -6.97 6.60 -10.06
Bonsall clay loam 0-25 -9.91 11.58 -14.12
Diablo clay
Diablo clay loam
0-15
0-15
-7.77
-7.65
6.40
6.15
-10.27
-10.24
Fallbrook loamy sand 25-51 -7.91 8.36 -11.46
Fiander clay loam 0-15 -7.98 5.45 -9.57
Haines silt loam 20 -7.84 7.14 -11.10
Hanford loam 0-10 -7.14 7.06 -10.77
Hesperia sandy loam 0-7.6 -8.24 8.38 -11.85
Holtville sandy loam 61-76 -8.07 7.36 -11.41
Imperial clay 15-46 -7.74 6.71 -10.94
Nohili silt loam 0-23 -7.74 7.16 -9.96
Pachappa loam
Pachappa sandy loam
0-25
25-51
-7.57
-8.48
7.61
8.26
-10.90
-12.22
Porterville silty clay loam 0-7.6 -6.74 5.95 -9.09
Reagan clay loam Surface -7.36 6.71 -10.85
Ryepatch silty clay loam 0-15 -7.65 6.35 -10.12
Sebree silt loam 0-13 -6.57 6.21 -8.71
Wasco sandy loam 0-5.1 -7.10 7.13 -9.70
Wyo silt loam   -10.05 11.91 -12.90
Yolo loam 0-15 -7.78 6.78 -11.15
Average logK(int)
Standard Deviation
  -7.77
0.87
7.29
1.62
-10.77
1.26
   

 

 


Last Modified: 10/14/2005
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