Measuring organic carbon in Calcarosols: understanding the pitfalls and complications

Soil Research ◽  
2012 ◽  
Vol 50 (5) ◽  
pp. 397 ◽  
Author(s):  
Aaron Schmidt ◽  
Ronald J. Smernik ◽  
Therese M. McBeath
Keyword(s):  
Organic Carbon ◽  
Hydrofluoric Acid ◽  
Acid Treatment ◽  
Calcareous Soils ◽  
Soil Condition ◽  
Wet Oxidation ◽  
Sulfurous Acid ◽  
The Difference ◽  
Pre Treatment ◽  
Dry Combustion

The measurement of soil organic carbon (OC) is important for assessing soil condition and improving land management systems, as OC has an important role in the physical, chemical, and biological fertility of soil. The OC contents of Calcarosols often appear high compared with other Australian soil types with similar fertility. This may indicate either systematic overestimation of OC in Calcarosols or the existence of a mechanism of OC stabilisation specific to carbonate-rich soils. This study compares three dry combustion techniques (dry combustion with correction for carbonate-C determined separately, dry combustion following sulfurous acid treatment, and dry combustion following treatment with hydrofluoric acid) and two wet oxidation techniques (Walkley–Black and Heanes) for the measurement of soil OC content, to determine which method is best for Calcarosols. Nine calcareous and nine non-calcareous soils were analysed. Of the methods, dry combustion with carbonate-C correction and dry combustion following sulfurous acid pre-treatment were found to be unsuitable for highly calcareous soils. Dry combustion with carbonate-C correction was unsuccessful primarily due to incomplete conversion of carbonate to CO2 under the combustion conditions used. However, even if this problem could be overcome, the method would still not be suitable for highly calcareous soils since it would involve the measurement of a relatively small value (OC) as the difference of two much larger values (total C and carbonate-C). Sulfurous acid pre-treatment was unsuitable because it did not remove 100% of carbonate present. Although the remaining dry combustion technique (i.e. following hydrofluoric acid treatment) did not have such problems, it did give very different (and much lower) OC estimations than the two wet oxidation techniques for the highly calcareous soils. These results are consistent with carbonate minerals interacting with and stabilising a substantial quantity of soluble OC. This has implications for the way OC levels should be measured and interpreted in Calcarosols, in terms of both fertility and C stabilisation and sequestration.

Improving the biological stability of drinking water by ion exchange

2011 ◽  
Vol 11 (1) ◽  
pp. 107-112 ◽  
Author(s):  
A. Grefte ◽  
M. Dignum ◽  
S. A. Baghoth ◽  
E. R. Cornelissen ◽  
L. C. Rietveld
Keyword(s):  
Drinking Water ◽  
Organic Carbon ◽  
Ion Exchange ◽  
Biofilm Formation ◽  
Formation Rate ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Biological Stability ◽  
Biological Activated Carbon ◽  
Pre Treatment

To guarantee a good water quality at the consumer’s tap, natural organic matter (NOM) should be (partly) removed during drinking water treatment. The objective of this research is to measure the effect of NOM removal by ion exchange on the biological stability of drinking water. Experiments were performed in two lanes of the pilot plant of Weesperkarspel in the Netherlands. The lanes consisted of ozonation, softening, biological activated carbon filtration and slow sand filtration. Ion exchange in fluidized form was used as pre-treatment in one lane and removed 50% of the dissolved organic carbon (DOC); the other lane was used as reference. Compared to the reference lane, the assimilable organic carbon (AOC) concentration of the finished water in the lane pretreated by ion exchange was 61% lower. The biofilm formation rate of the finished water was decreased with 70% to 2.0 pg ATP/cm2.day. The achieved concentration of AOC and the values of the biofilm formation rate with ion exchange pre-treatment showed that the biological stability of drinking water can be improved by extending a treatment plant with ion exchange, especially when ozonation is involved as disinfection and oxidation step.

scholarly journals Influence of the Bottom Color Modification and Material Color Modification Process on the Performance of Modified Poplar

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 660
Author(s):  
Qingqing Liu ◽  
Di Gao ◽  
Wei Xu
Keyword(s):  
Chemical Properties ◽  
Target Color ◽  
Modification Process ◽  
Red Color ◽  
The Difference ◽  
Pre Treatment ◽  
Physical And Chemical ◽  
Surface Differentiation ◽  
Color Modification ◽  
And Chemical Properties

According to the old surface coating process of European and American furniture, the surface of modified poplar is first differentiated pre-treatment, and then the bottom color modification and material color modification are respectively applied to the modified poplar after the surface differentiation treatment. The visual physical quantity and physical and chemical properties were measured and compared with mahogany, which is commonly used in old furniture in Europe and America to explore the effect of colorants and coloring steps, as well as different surface pretreatments on the coloring effect. Finally, it is concluded that continuous coloring operations can narrow the difference in brightness and red color value in the coloring layer of modified poplar and mahogany. Continuous coloring operations increase the difference between the yellow-green color values of modified poplar and mahogany. Therefore, the coloring difference between modified poplar and mahogany was affected by the colorant and coloring steps. Through color accumulation, the gap between the two in the target color coloring effect can be reduced, thereby reducing the difference between the coloring effect of modified poplar and mahogany.

Effects of Dissolved Organic Carbon on Phosphate Retention on Two Calcareous Soils

2005 ◽  
Vol 53 (1) ◽  
pp. 84-89 ◽  
Author(s):  
Manuel Fernández-Pérez ◽  
Francisco Flores-Céspedes ◽  
Emilio González-Pradas ◽  
María Delores Ureña-Amate ◽  
Matilde Villafranca-Sánchez ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Calcareous Soils ◽  
Phosphate Retention

Wet oxidation: a pre-treatment procedure for sludge

2002 ◽  
Vol 22 (6) ◽  
pp. 611-616 ◽  
Author(s):  
Nevim Genç ◽  
Şems Yonsel ◽  
Levent Dağaşan ◽  
A.Nur Onar
Keyword(s):  
Wet Oxidation ◽  
Treatment Procedure ◽  
Pre Treatment

scholarly journals EFFECT OF ETCHING AS PRE-TREATMENT FOR ELECTROLESS COPPER PLATING ON SILICON WAFER

2017 ◽  
Vol 79 (7) ◽  
Author(s):  
Shazatul Akmaliah Mior Shahidin ◽  
Nor Akmal Fadil ◽  
Mohd Zamri Yusop ◽  
Mohd Nasir Tamin ◽  
Saliza Azlina Osman
Keyword(s):  
Silicon Wafer ◽  
Hydrofluoric Acid ◽  
Copper Film ◽  
Etching Time ◽  
Electroless Copper Plating ◽  
Cross Sectional ◽  
Electroless Process ◽  
Pre Treatment ◽  
Sectional Analysis ◽  
Mechanical Bonding

Metallic coatings, such as copper films can be easily deposited on semiconductor materials like silicon wafer without prior surface pre-treatment using the electroless process. However, the adhesion of the copper film can be very weak and can easily peels off. In this study, the effect of etching in hydrofluoric acid solution as a surface pre-treatment prior to electroless plating on silicon wafer was studied. The etching time in hydrofluoric acid was varied at 1, 3 and 5 minutes in order to investigate the adhesion behaviour of the coating layer. The surface morphology of the electroless plated samples was observed using a field emission scanning electron microscope (FESEM) and the coating thickness was measured using cross sectional analysis. The results showed that longer etching time (5 minutes) produced thicker Cu deposits (8.5μm) than 1 minute etching time (5μm). In addition, by increasing the etching time, the mechanical bonding between the copper film and the substrate is improved.

scholarly journals Tillage in Relation to Distribution of Nutrients and Organic Carbon in the Soil

2011 ◽  
Vol 57 (1) ◽  
pp. 21-30
Author(s):  
Božena Šoltysová ◽  
Martin Danilovič
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Total Nitrogen ◽  
Spring Barley ◽  
Conventional Tillage ◽  
Soil Tillage ◽  
Reduced Tillage ◽  
Available Phosphorus ◽  
No Tillage ◽  
The Difference

Tillage in Relation to Distribution of Nutrients and Organic Carbon in the SoilChanges of total nitrogen, available phosphorus, available potassium and soil organic carbon were observed on gleyic Fluvisols (locality Milhostov) at the following crops: grain maize (2005), spring barley (2006), winter wheat (2007), soya (2008), grain maize (2009). The experiment was realized at three soil tillage technologies: conventional tillage, reduced tillage and no-tillage. Soil samples were collected from three depths (0-0.15 m; 0.15-0.30 m; 0.30-0.45 m). The ratio of soil organic carbon to total nitrogen was also calculated.Soil tillage affects significantly the content of total nitrogen in soil. The difference between the convetional tillage and soil protective tillages was significant. The balance showed that the content of total nitrogen decreased at reduced tillage by 5.2 rel.%, at no-tillage by 5.1 rel.% and at conventional tillage by 0.7 rel.%.Similarly, the content of organic matter in the soil was significantly affected by soil tillage. The content of soil organic carbon found at the end of the research period was lower by 4.1 rel.% at reduced tillage, by 4.8 rel.% at no-tillage and by 4.9 rel.% at conventional tillage compared with initial stage. The difference between the convetional tillage and soil protective tillages was significant.Less significant relationship was found between the soil tillage and the content of available phosphorus. The balance showed that the content of available phosphorus was increased at reduced tillage (by 4.1 rel.%) and was decreased at no-tillage (by 9.5 rel.%) and at conventional tillage (by 3.3 rel.%).Tillage did not significantly affect the content of available potassium in the soil.

scholarly journals The Use of Heap Bioleaching as a Pre-Treatment for Platinum Group Metal Leaching

2017 ◽  
Vol 262 ◽  
pp. 151-154
Author(s):  
James M. Mwase ◽  
Jochen Petersen
Keyword(s):  
Platinum Group Metal ◽  
Metal Leaching ◽  
Flotation Concentrate ◽  
Group Metal ◽  
Two Samples ◽  
Heap Bioleaching ◽  
Mineral Recovery ◽  
The Difference ◽  
Pre Treatment

Two samples, a Platreef flotation concentrate and coarse ore (<6 mm), were column bioleached at 65°C using a culture dominated by Metallosphaera hakonensis. Based on solution assays, extractions in excess of 90% Cu and Ni were achieved from the flotation concentrate, while from the coarse ore 96% Cu and 67% Ni extractions were achieved. The difference in extraction levels and leaching patterns despite identical conditions used for both samples is discussed, as is the performance of the samples during a follow-up leach step using cyanide to extract the PGMs in a separate column leach experiment. While the recovery of Pd and Au was excellent during these steps, recovery of Pt was limited to 35% after 45 days for the concentrate and 56% after 60 days for the whole ore material, primarily due to the presence of a refractory Pt mineral. Recovery from a concentrate without pre-treatment was substantially lower.

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