scholarly journals Measurement of Total Free Iron in Soils by H2S Chemisorption and Comparison with the Citrate Bicarbonate Dithionite Method

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Shui-Sheng Fan ◽  
Feng-Hsiang Chang ◽  
Hsin-Ta Hsueh ◽  
Tzu-Hsing Ko

Free iron is one of the major analytical items for soil basic properties. It is also an important indicator for understanding the genesis of soil, soil classification, and soil distribution behavior. In this study, an alternative analytical method (chemisorption) based on thermodynamic knowledge was proposed for measurement of total free iron oxides in soils. Several representative soil samples belonging to alfisols, ultisols, inceptisols, and entisols were collected from Taiwan and tested by the chemisorption, and the estimated total free iron oxides were compared with those measured from the traditional citrate bicarbonate dithionite (CBD) method. Experimental results showed that the optimal operating temperature was found to be at 773 K and the carbon monoxide (CO) is the best gaseous reagent to promote the formation of FeS. The estimated total free iron oxides for soil samples determined from the chemisorption in the presence of CO were very close to those from the CBD technique. The result of regression indicates that the estimated total free iron is strongly correlated with the CBD-Fe content (R2=0.999) in the presence of CO.

1965 ◽  
Vol 45 (2) ◽  
pp. 127-138 ◽  
Author(s):  
J. E. Brydon

The Arago, Barney, and Holmesville soils, Podzols from Quebec, Nova Scotia, and New Brunswick, respectively, each had friable Bfh horizons with moderate granular structure, and with organic matter and free Fe2O3 contents greater than the Ae and C horizons. The Arago and Holmesville had thin Bhft horizons containing over 10% organic matter and 5% free iron oxides. The C horizons of these two soils had some features characteristic of fragipans.The B horizons of the three soils had a high "pH-dependent charge component" in the C.E.C. values. The "permanent charge component" was similar throughout the Arago profile except for the Bhft horizon where clay accumulation had occurred.Translocation of clay from the Ae to the upper B horizons was indicated by the twofold increase in clay content and the relative enrichment of fine clay in the B horizons. Removal of free iron affected the clay contents differently in the different: horizons but the maximum clay content in the upper B horizons remained. The definitions of Orthic Podzols, Textural Podzols, and t horizons should be re-examined.


2017 ◽  
Vol 1 (1) ◽  
pp. 89-94
Author(s):  
Sherwan Kafoor

Asnawa soils contain high amounts of iron oxides. These minerals apply much influence on different soil properties, of which the most observable is colour. The objective of this study was to conclude if colour of soils measured by visual methods can be parameterized to quantify soil Fe oxides. The examined area was divided to three zones (zone A, zone B and zone C) according to their colour intensity. Forty soil samples were examined for their colour and iron oxide contents. Their colour were ranged between 5YR (H) 2.5 (V/C) to 5YR (H) 5/8 (V/C). The average values of free Fe oxide in the soils of the three zones were 52.1%, 36.8% and 15.9% respectively. A new formula was derived to measure colour intensity. A highly significant correlation was found between colour intensity and concentrations of Fe oxides in the examined soils.


2014 ◽  
Vol 6 (22) ◽  
pp. 8930-8939 ◽  
Author(s):  
Aderval S. Luna ◽  
Igor C. A. Lima ◽  
Werickson F. C. Rocha ◽  
Joyce R. Araújo ◽  
Alexei Kuznetsov ◽  
...  

Soil classification is crucial for its cultivation preparation in countries that export several agricultural commodities.


Fractals ◽  
2001 ◽  
Vol 09 (03) ◽  
pp. 305-316 ◽  
Author(s):  
F. J. CANIEGO ◽  
M. A. MARTÍN ◽  
F. SAN JOSÉ

In this paper, several features of pore-size soil distribution are first analyzed, suggesting that they are closer to those of singular measures than to those of distributions with smooth density. In a second step, the weighted singularity strength of an experimental measure obtained by image analysis of soil samples is evaluated. The results of this analysis show the singular nature of pore-size distribution. Finally, the distribution is characterized by means of a spectrum of entropies computed on distorted measures associated with the original experimental measure.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Cynthia A. Coles ◽  
Joseph A. Arisi ◽  
Marion Organ ◽  
Geoff I. Veinott

Concentrations of Cu, Cr, and As in soils surrounding 26 Douglas Fir Chromated Copper Arsenate (CCA) treated utility poles and in rainwater runoff from a new CCA treated utility pole segment (log) suspended outside in a cylinder were studied. The age of the utility poles, distances from the poles, rainfall amounts, and characteristics of soil samples including cation exchange capacity (CEC), pH, and total organic carbon (TOC) were considered. Heavier rainfall, damp conditions, and more weathered poles contributed to the greatest leaching of Cu, Cr, and As. The maximum measured soil concentrations of Cu, Cr, and As were 37.5, 65.5, and 38.9 mmol/kg and maximum Cu, Cr, and As concentrations in rainwater run-off were 14, 77.7 and 55.8 μmol/L. Metal concentrations decreased with distance from the poles and, except at one utility pole location, Cu was the most leached of the three elements. The As appeared to have greater mobility in the soil than the Cr. Along the transmission line nearest the coast and from which the greatest amount of samples was collected, soil CEC and TOC values were the highest and the CEC and TOC were directly and strongly correlated.


Author(s):  
Mahmood D. Ahmed ◽  
Alaa D. Almurshedi ◽  
Hayder H. Alwan

This study presents a comprehensive set of laboratory works for the examined soil layers extracted from Baghdad city (specifically from Alkadhimya, Alaitaifiya, and Alhurriya) to illustrate their engineering properties. The researchers have adopted the unified soil classification system for soil classification purposes. Also, the direct shear test was performed for soil samples with various degrees of saturation (0%, 25%, 50%, 75%, and 100%). The test results have shown a significant reduction in cohesion property with higher moisture content within soil samples. Also, a noticeable reduction in angle of internal friction value has occurred with such changes. Furthermore, it has been found that the bearing capacity of unsaturated soils ranged between 2000 and 3000 KPa, and about 500-700 KPa for the soaked soil samples.


2019 ◽  
Vol 14 (2) ◽  
pp. 95-106
Author(s):  
Oluwaseun Adetayo ◽  
Olugbenga Amu ◽  
Sunday Alabi

AbstractThis study investigated the suitability of pulverized snail shell (PSS) as partial replacement of cement stabilized soil in foundation constructions. Preliminary and engineering tests were carried out on the soil samples. The optimum cement content fixed at 11% in correlation to Unified Soil Classification System, the PSS was introduced at varying percentages of 2%, 4%, 6%, 8% and 10%. Results revealed that, addition of PSS and 11% cement to lateritic soil caused a reduction in both liquid limits and plasticity index and an increased in plastic limits for all samples. Engineering tests showed the maximum dry density at optimum cement increased from 1493.34 ± 103.58 kg.m−3 to 1632 ± 435.81 kg.m−3 for sample A; 1476.77 ± 367.51 kg.m−3 to 1668 ± 202.58 kg.m−3 for sample B; 1460.77 ± 623.58 kg.m−3 to 1651 ± 135.45 kg.m−3 for sample C. The CBR recorded highest value at 4%PSS optimum cement for all samples. The addition of pulverized snail shell increased the strength of cement stabilized lateritic soil for structural foundation construction.


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