Distribution of soluble heavy metals between ionic and complexed forms in a saturated sediment as affected by pH and redox conditions

1998 ◽  
Vol 37 (6-7) ◽  
pp. 165-171 ◽  
Author(s):  
W. H. Patrick ◽  
M. Verloo
Keyword(s):  
Organic Matter ◽  
Metal Complexes ◽  
Cation Exchange ◽  
Size Distribution ◽  
Size Range ◽  
The Other ◽  
Redox Conditions ◽  
Soluble Organic Matter ◽  
Other Hand ◽  
Reducing Conditions

Research was undertaken to determine the effects of pH and redox potential on heavy metal speciation and on the size distribution of the organo-metal complexes in the soluble fraction of sediment-water systems. A cation exchange technique was effective in separating free and complexed metal ions. Fe, Mn and Zn differed in the extent of complexation with soluble organic matter. Under reducing conditions approximately two thirds of the soluble Fe was in a complexed form that was not sorbed in passing through the cation exchange resin. Soluble Mn on the other hand, was almost completely ionic under reducing conditions, with only a trace amount passing through the resin column. Over 90 percent of the soluble Zn was complexed under reduced conditions, with only 9 percent sorbed onto the resin. The complexed Fe and Zn were bound to soluble organic matter particles with equivalent molecular weight greater than 25,000 while Mn passed through this size filter. There were marked differences in the size distribution of the various organo-metal complexes under different redox and pH conditions. The soluble Fe was associated with both the largest and smallest size ranges of soluble organic matter. The effect of pH was most evident in the smallest size range with much more complexed iron being present at low pHs. Mn, on the other hand, was associated with only the smallest size range under all pH and redox conditions, reflecting its ionic nature. The greater solubility and mobility of Mn probably accounts for it being depleted relative to iron in Gulf Coast sediments. Hg and Pb were associated with only the largest size soluble complexes and were little affected by pH and redox conditions.

scholarly journals Determination of the Ratios of Ligands to Metal Ion of some Metal Complexes of Triazoles by Using Eleetronie Speetra in Organie Solvents

2004 ◽  
Vol 1 (1) ◽  
pp. 110-115
Author(s):  
Baghdad Science Journal
Keyword(s):  
Solid State ◽  
Metal Complexes ◽  
Electronic Spectra ◽  
Metal Ion ◽  
The Other ◽  
Molar Ratio ◽  
Other Hand

We found that 4,5- diphenyl- 3(2- propynyl) thio- 1??-triazole [1? forms a complex with Pd (11) ion of ratio 1:1 which absorbs light in CH2CI2 at 400 nm, and 4,5- diphenyl- 3(2- propenyl) thio- 1,2,4- triazole [II] forms complexes with Pd (II) ion of ratio 1:1 which absorbs light at 390 nm, and of ratio 2:1 which absorbs light at 435 nm. On the other hand, we found that the new derivative 4- phenyl- 5( p- amino phenyl) -3- mercapto- 1,2,4- triazole ?111? forms complexes with Cu (II) ion of the ratio 1:1 which absorbs light at 380 nm, with Ni (II) ion of the ratio 3:1 which absorbs light at 358 nm; and with Co (11) ion of the ratio 3.2:1 which absorbs light at 588 nm. The ratio of the complexes were determined by measuring the electronic spectra of the complexes in CH2G2 and (CH^NCHO at different concentrations ofthe ligands and f?xed ' •' of the metal ion in every case, then applying the molar ratio plots on the data. Our results were confirmed by precipitating most ofthe above complexes in solid state, and then each complex was analyzed elementally.

scholarly journals Differences in soil organic matter and humus of sandy soil after application of biochar substrates and combination of biochar substrates with mineral fertilizers

2020 ◽  
Vol 23 (3) ◽  
pp. 117-124
Author(s):  
Dušan Šrank ◽  
Vladimír Šimanský
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Carbon Content ◽  
Humic Substances ◽  
Sandy Soil ◽  
The Other ◽  
Mineral Fertilizers ◽  
Other Hand ◽  
Sheep Manure ◽  
The Impact

The effort to achieve the sustainable farming system in arable soil led to the intensive search for a new solution but an inspiration can also be found in the application of traditional methods of soil fertility improvement as it is shown in numerous examples in history. Recently many scientific teams have focused their attention on the evaluation of biochar effects on soil properties and crop yields. Since there are a lot of knowledge gaps, especially in explanations how biochar can affect soil organic matter (SOM) and humus substances, we aimed this study at the solution of these questions. Therefore, the objective of the experiment was to evaluate the impact of two biochar substrates (B1 – biochar blended with sheep manure, and B2 – biochar blended with sheep manure and the residue from the biogas station) at two rates (10 and 20 t ha-1) applied alone or in combination with mineral fertilizers (Urea was applied in 2018, at rate 100 kg ha-1, and Urea at rate 100 kg ha-1 + AMOFOS NP 12-52 at 100 kg ha-1 were applied in 2019) on the quantity and quality of SOM and humus of sandy soil (Arenosol, Dolná Streda, Slovakia). The results showed that application of the biochar substrates together with mineral fertilizers (MF) had more pronounced effect on the organic matter mineralization in the sandy soil which resulted in low accumulation of soil organic carbon (Corg) and labile carbon compared to biochar substrates treatments without MF. The share of humic substances in Corg significantly decreased by 16, 50, 16 and 24% in B1 at 10 t ha-1, B1 at 20 t ha-1, B2 at 10 t ha-1 and B2 at 20 t ha-1 treatments, respectively, compared to the control. A similar tendency was observed for biochar substrates treatments + MF, compared to MF control. The carbon content of humic substances (CHS) was equal to 4.40 – 5.80 g kg-1 and the biochar substrates had statistically significant influence on CHS content. On average, there was a smaller decrease of CHS in B1 at rate 10 t ha-1 than at rate 20 t ha-1 and no effect of B2 compared to control. The carbon content of fulvic acid (CFA) was 9% higher in B1 at 10 t ha-1, and 20 t ha-1, 47% higher in B2 at 10 t ha-1 and 17% higher in B2 at 20 t ha-1 compared to control. As a result of biochar substrates + MF application, the reduction in CFA was observed. The results showed a decrease of CHA : CFA ratio with association to biochar substrates alone application compared to control on one hand, and a wider of CHA : CFA ratio in biochar substrates + MF treatments in comparison to MF control on the other hand. Humus stability was increased in biochar substrates alone treatments compared to control, on the other hand, compared to MF control, the application of biochar substrates + MF resulted in a lower humus stability.

Influence of Task and Subject Variables in the Squares Test of Leveling-Sharpening

1968 ◽  
Vol 27 (1) ◽  
pp. 211-218
Author(s):  
Albert R. Gilgen ◽  
Paul Bakan
Keyword(s):  
Test Performance ◽  
Size Range ◽  
Cognitive Structure ◽  
The Other ◽  
Response Scale ◽  
Instructional Information ◽  
Memory Traces ◽  
Other Hand ◽  
Subject Variables ◽  
The Way

Leveling-sharpening, an hypothesized dimension of cognitive structure, is generally operationally defined in terms of differentiation and/or trend measures of Squares Test performance, both types of measures being assumed to reflect the degree to which memory traces of the stimuli (squares of light) assimilate. The findings of the present study of 300 Ss indicate that differentiation scores to some degree reflect: (a) the way Ss interpret the instructions concerning the response scale they are to use and/or (b) S's motivation to perform the task. Trend scores, on the other hand, were found to be a function, in part, of the degree to which S's rely on the instructional information given them concerning the size range of the squares, there being some evidence that women rely on this information more so than men.

scholarly journals Changes in Soil Structure and Soil Organic Matter Due to Different Severities of Fire

2015 ◽  
Vol 34 (3) ◽  
pp. 226-234 ◽  
Author(s):  
Vladimír Šimanský
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Structure ◽  
Cold Water ◽  
Fire Severity ◽  
Size Fraction ◽  
Water Soluble ◽  
Hot Water ◽  
The Other ◽  
Other Hand

Abstract The effect of different fire severity on the changes of the soil organic matter (SOM) and soil structure was evaluated. Soil samples were collected (May 2010) in the locality of Nitra-Dražovce (Slovakia) from the following plots: 1) control (unburned place), 2) low severity of fire and 3) higher severity of fire. The results showed that the content of water-stable microaggregates (WSAmi) increased by 20% in the area with a low severity of fire, but on the other hand, it decreased by 42% in the area with the higher severity of fire in comparison to control. The higher severity of fire resulted in a decrease of smaller size fractions of water-stable macroaggregates (WSAma) (0.5−0.25) and a low severity of fire resulted in the decrease of WSAma 2−0.5 mm. On the other hand, the content of WSAma in the size fraction >5 mm was higher by 54% and by 32% in the lower and higher severity of fire, respectively, than in unburned soil. The higher severity of fire had a more positive effect on increases of the structure coefficient and coefficient of aggregate stability, as well as on the decrease of the vulnerability coefficient compared to the low severity of fire. After burning, the contents of soil organic carbon (Corg) and labile carbon were significantly increased by the severity of fire. However, the low severity of fire affected more markedly the increase of hot water-soluble and cold water-soluble carbon than the higher severity of fire. After burning and due to the severity of fire, both the carbon of humic and carbon of fulvic acids ratios and SOM stability increased. The parameters of SOM due to fire significantly increased also in WSA with the least changes in WSAmi. The results showed that a low severity of fire increased Corg mainly in WSAma >2mm and WSAmi, whereas high severity fire increased Corg content in the smaller fraction of WSAma.

Sound Absorption Behavior of Porous Al Produced by Spacer Method

2006 ◽  
Vol 15-17 ◽  
pp. 422-427
Author(s):  
Tetsumune Kuromura ◽  
Masataka Hakamada ◽  
Y. Chen ◽  
Hiromu Kusuda ◽  
Mamoru Mabuchi
Keyword(s):  
Absorption Coefficient ◽  
Pore Size ◽  
Sound Absorption ◽  
Size Range ◽  
Absorption Capacity ◽  
The Other ◽  
Sound Absorption Coefficient ◽  
Specimen Thickness ◽  
Pore Sizes ◽  
Other Hand

Porous Al specimens with a pore size range from 212-300 to 610-700 μm, a porosity from 85 to 95% and a specimen thickness from 2 to 20 mm were produced by the spacer method, and their sound absorption capacity was investigated. For these specimens, sound absorption coefficient increased with increasing porosity. On the other hand, sound absorption coefficient varied inconsistently with the variation of pore sizes. The latter may be attributed to variation of aperture sizes of each specimen because the porous Al specimens with differerent pore sizes produced by the spacer method should have different aperture sizes. Sound absorption coefficient increased at the frequency below 2000 Hz with increasing specimen thickness.

Impact of Fuel Preparation System on Combustion Process and Exhaust Emissions

2003 ◽  
Author(s):  
S. Pischinger ◽  
M. Umierski
Keyword(s):  
Particulate Matter ◽  
Size Distribution ◽  
Diesel Fuel ◽  
Ambient Air ◽  
Common Rail ◽  
Sulphur Content ◽  
The Other ◽  
Injection Timing ◽  
Heavy Fuel Oil ◽  
Other Hand

In the past decade, the quality of Heavy Fuel Oil (HFO) has not improved or even declined in general. The progress in refinery techniques allowed to use a higher percentage of the crude oil for light fuels and other components. Therefore, the concentration of heavy components and agglomerates in the residual fuel increased. On the other hand, a better exhaust quality without compromising the superior fuel consumption of HFO-fuelled engines can only be gained by improved fuel injection. High injection pressures, rate shaping and electronic control of injection timing as well as new injection techniques like Common-Rail will be common features of engines for the next decades. Unfortunately, electronic controlled unit pumps and moreover, Common Rail systems are very sensitive to fuel quality, especially the content of water, sediments, agglomerates and other sludge. If ran on fuel processed by today’s fuel preparation system, wear would be excessive or damages will take place. On the other hand, if conventional on-board purification is intensified, the percentage of fuel deposit will rise and lower the over-all efficiency. To observe effects of fuel composition, a single cylinder research engine (250 mm bore/320 mm stroke) is fuelled by HFO in typical operation modes including different speeds and loads. Diesel fuel was also used to compare the results with another fuel of e.g. different sulphur content to separate effects on particulate matter. The high, typical sulphur content of the used HFO of about 3% increases the particulate matter; approx. 30% are sulphur products. The Soluble Organic Fraction (SOF, unburned fuel and oil) of PM is significantly higher compared to diesel fuel (50...70% to 10%). This impacts the particulate size distribution as well: although the main fraction of particulates consist of a size from 100...400nm for diesel and HFO, the number of small particulates (approx. 50 nm) is different, depending on the Sulphur content as this size consists of small condensates; therefore, the number may also be impacted by ambient air humidity. By use of different components for fuel preparation, the size, distribution and content of agglomerates can be impacted, but re-agglomeration occurs fast within minutes and must be taken into account. The differences in agglomerates does not result in a different total exhaust particulate mass. The slight effects found within the test are not significant and are in addition to that affected by ambient conditions. The fuel preparation, especially the use of homogenization equipment, needs more development efforts. For example, a mechanical homogenization apparatus can crack agglomerates and improve fuel homogeneity, but may fail to bring the size of agglomerates to a dimension that the filter is relieved.

Distribution of metallic trace elements (ETM) in surface soils around the Mediouna discharge (southern of Casablanca)

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Trace Elements ◽  
Organic Matter ◽  
Spatial Distribution ◽  
Soil Samples ◽  
The Other ◽  
Surface Soils ◽  
Other Hand ◽  
Metallic Trace Elements ◽  
Low Concentrations ◽  
Uncontrolled Landfill

The objective of present research was to characterize the surface soils located at 300, 600 and 1000 m of an uncontrolled landfill. The work also aims to evaluate the levels and spatial distribution of metallic trace elements (Cd, Pb, Cu, Ni, Zn, Cr, Co and As) in these soils. Soil samples were collected in 36 points around the landfill. Results showed that Cd, Pb, Zn are concentrated in the soils rich in clay and carbonates, and in organic matter, located at 300 m from the landfill. The basic pH of all soils enhances the retention of these metals. On the other hand, As present in soils at 300, 600 and 1000 m at concentrations slightly higher than those of referenced soils were apparently mobilized by water from the solid/water interfaces. The other metals Cu, Ni, Co, Cr are present at very low concentrations.

513. The effect of different cream treatments during the pasteurization process on the size distribution of fat globules in cream and butter

1953 ◽  
Vol 20 (2) ◽  
pp. 201-211 ◽  
Author(s):  
R. M. Dolby
Keyword(s):  
Thin Film ◽  
Uniform Distribution ◽  
Size Distribution ◽  
Considerable Increase ◽  
The Other ◽  
Gel Formation ◽  
Microscope Slide ◽  
Fat Globules ◽  
Other Hand ◽  
Counting Chamber

A method for determining the size distribution of fat globules in cream has been described. A thin film (20 μ) of the diluted cream on a microscope slide is preferred to a deeper preparation (0·1 mm.) in a counting chamber in which rise of fat globules to the upper surface is necessary for easy observation. The latter method is less convenient and can give too low an estimate of the proportion of the smallest globules (1 μ and under).Cream should be diluted 1 in 50 and the concentration of gelatin in the dilution should be sufficient (4–6%) to give a rapid gel formation. The mixture should be cooled till the gelatin thickens before being transferred to the slide if it is to give the most uniform distribution of globules.It is shown that Vacreator-treatment of cream causes a considerable increase in the proportion of fat present as globules less than 2 μ and a small increase in the proportion present as globules over 10 μ in diameter. Flash-pasteurization, on the other hand, causes a slight decrease in the proportion of fat present as small globules and a considerable increase in that present as large globules.Butter from flash-pasteurized cream contains numerous large fat globules and fat aggregates, while butter from Vacreator-treated cream contains few large globules. It is suggested that the more uniform subdivision of fat in butter from Vacreator-treated cream explains why butter from Vacreator-treated cream is superior in texture to butter from flash-pasteurized cream.

XIII.—A Chemical Examination of the Organic Matter in Oil-Shales

1914 ◽  
Vol 34 ◽  
pp. 190-201 ◽  
Author(s):  
John B. Robertson
Keyword(s):  
Organic Matter ◽  
Microscopic Examination ◽  
Oil Shale ◽  
The Other ◽  
Chemical Examination ◽  
Chemical Action ◽  
Orange Yellow ◽  
Other Hand ◽  
Bacterial Action ◽  
Oil Shales

Investigations into the nature of the organic matter in oil-shales began at the time of the famous Torbanehill case in 1854, when experts attempted to settle the question as to whether the substance known as “ Torbanite ” or “ Boghead Mineral” was a coal or an oil-shale. Several witnesses at the trial (Gillespie v. Russel, Session Papers, 1854) maintained that the oilproducing material in the Mineral was of organic origin, while others pronounced it to be bituminous and produced by subaqueous eruptions. T. S. Traill, M.D., proposed for the Boghead Mineral the name “ Bitumenite,” as it seemed to him to “ consist of much bitumen, mingled with earthy matter” (Trans. Roy. 8oc. Edin., 1857, xxi. p. 7). Dr Redfern (Quart. Jonrn. Micros. Soc, 1855, x. pp. 118-119), on the other hand, supposed the round orange-yellow bodies which occur in torbanite to have had their origin in "“ a mass of vegetable cells and tissues which have been disintegrated and otherwise changed by maceration, pressure, and chemical action, and subsequently solidified."” C. E. Bertrand and B. Renault (Bull. Soc. Hist. Nat. Autun, 1892-3) on microscopic examination have classed these bodies as the remains of gelatinous algae which have been altered by bacterial action.

Sampling Benthos and Substrate Materials, Down to 50 microns in Size, in Shallow Streams

1971 ◽  
Vol 28 (6) ◽  
pp. 849-860 ◽  
Author(s):  
J. H. Mundie
Keyword(s):  
Size Distribution ◽  
Inorganic Material ◽  
Size Range ◽  
The Other ◽  
Vertical Stratification ◽  
Fish Biology ◽  
Size Scale ◽  
Bed Materials ◽  
Contrasting Habitats ◽  
Cumulative Curves

Stream bed materials, both biotic and abiotic, in the size range 50 μ–ca. 200 mm can be sampled unselectively, in shallow streams, with a simple inexpensive apparatus consisting of a box provided with an adjustable upstream inlet, and, downstream, two nets, one within the other. Collected materials are wet-sieved and the volumes of inorganic material passed by successively finer sieves are plotted as cumulative curves against a logarithmic size scale. Curves are given for materials from three contrasting habitats: a riffle, and pool, of a coastal stream, and an artificial spawning channel. Examples are also given of the densities, size distribution, and vertical stratification of invertebrates from these habitats. Applications of the method to studies on fish biology, invertebrate ecology, and geomorphology are indicated.

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