The effect of temperature on tight metal binding by peat and soil derived solid humic acids

The brown biomaterials called humic acids (HA) in peats and soils retain water and bind metal cations and other solutes. Studies of the interactions of purified solid peat and soil-derived HA from different countries with metal cations in water probe HA microstructures and help to characterize the metal binding sites. Labile cations such as Caaq2+, Co aq2+, Cu aq2+, Fe aq3+, Mg aq2+ and Mn aq2+ tightly bind to solid HAs in sequential steps. The isotherms A vs. c are well fitted with the Langmuir model and plots of 1/A vs. 1/c are linear for each step. Here, A is mmol bound metal g–1 HA and c is the equilibrium cation concentration (M). This paper compares the stoichiometric site capacities vi and equilibrium constants Ki for tight binding of Ca aq2+, Co aq2+, Cu aq2+, Fe aq3+, Mg aq2+ and Mn aq2+ at different solid HA sites. Measurements at different temperatures give linearly correlated metal binding enthalpy and entropy changes, indicating that conformational changes and cation/HA hydration/dehydration are important factors in metal binding and release by solid HAs. Key words: Humic acids; metal binding; isotherms; thermodynamics

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Isolation of humic acid from oxidized lignite and complexation with metal cations

Hemijska industrija ◽

10.2298/hemind160628041c ◽

2017 ◽

Vol 71 (4) ◽

pp. 319-327

Author(s):

Benjamin Catovic ◽

Minela Sisic ◽

Majda Srabovic ◽

Melita Huremovic

Keyword(s):

Humic Acid ◽

Metal Ions ◽

Humic Acids ◽

Metal Binding ◽

Base Material ◽

Metal Cations ◽

Biological Properties ◽

Metal Nitrate ◽

Chemical Difference ◽

The Difference

Lignite is brown coal, which in its composition contains humic acids. Humic acids are produced by coal combustion, which leads to the enrichment of coal humic acids. Lignite, from the opet pit mine Sikulje, lignite ore ?Kreka?, Bosnia and Herzegovina, was fragmented and sieved to the appropriate size and used as a base material. The isolation of humic acid was carried out from pre-oxidized and dried lignite after which it was refined. Identification thus obtained humic acids was carried out by FTIR spectroscopy and its characterization of UV analysis which is determined by optical density of isolated humic acid and its complexation with metal cations. Data obtained by FTIR spectroscopic analysis of isolated humic acids show no significant structural and chemical difference in relation to the spectrum obtained for standard humic acids (Sigma Aldrich). UV analysis showed that isolated and standard humic acid have E4/E6 ratio in an appropriate range of 3?5, which indicates the presence of a large number of aliphatic structure. Based on the degree of humification was found that the isolated humic acids belong to the type B standard while humic acids belong to type A. The most important property of the humic substances is the ability to interact with the metal ions forming soluble or insoluble complexes which possess different chemical and biological properties and stability. The nature of the complex between humic acid and metal cation derived from the heterogeneous, polyelectric and polydispersive character humic acids that occurs due to the presence of a large number of functional groups. Complexation of humic acid is carried out with different concentrations of metal nitrate solutions and at different pH values. Different amounts of humic acids were used for the complexation. The amount of the free metal ions was measured with the ICP-OES methode. The data were also statistically analyzed with ANOVA. The results showed that increasing the pH reduces the concentration of metal ions adsorbed on humic acid and by increasing the concentrations and amounts of metal humic acid that power increases. On the basis of the difference in absorbance between metals and humic acids can be said that there is an interaction between the metal and the ligand and is based on absorbance values obtained can be determine the next set of metal binding to humic acids Pb>Zn>Ni>Cu.

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Ethidium Bromide Interaction with Poly(G)

Biophysical Reviews and Letters ◽

10.1142/s1793048014500039 ◽

2014 ◽

Vol 09 (03) ◽

pp. 239-247 ◽

Cited By ~ 1

Author(s):

Poghos H. Vardevanyan ◽

Marine A. Parsadanyan ◽

Mikayel V. Minasyants

Keyword(s):

Aqueous Solution ◽

Complex Formation ◽

Ethidium Bromide ◽

Conformational Changes ◽

Binding Constants ◽

Complex Structures ◽

Spectrophotometric Methods ◽

Binding Isotherms ◽

Different Temperatures ◽

Bromide Interaction

In current work we investigate the interaction between polyguanylic acid and Ethidium Bromide ( EtBr ) and the changes of thermodynamic parameters due to those interactions by spectrophotometric methods. From the binding isotherms, binding constants were calculated for three different temperatures and the changes of Gibbs free energy, entropy and enthalpy for complex-formation were determined. Complex-formation with four-stranded poly(G) structure needs less conformational changes in contrast with poly(G)poly(C), and due to that, EtBr binds with 5 and not 4 nucleotides. Obtained results confirm the concept that polyguanylic acids may form four-stranded complex structures with intercalating ligand EtBr in the aqueous solution.

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Kinetics and Thermodynamics of the Adsorption of Lead (II) on a Activated Carbon from Coconut Shells

Eurasian Chemico-Technological Journal ◽

10.18321/ectj233 ◽

2013 ◽

Vol 15 (4) ◽

pp. 283 ◽

Cited By ~ 2

Author(s):

L. Largitte ◽

P. Lodewyckx

Keyword(s):

Activated Carbon ◽

Standard Enthalpy ◽

Rate Constants ◽

Equilibrium Constants ◽

Activation Parameters ◽

Effect Of Temperature ◽

Standard Entropy ◽

Exponential Factor ◽

Different Temperatures ◽

Coconut Shells

The effect of temperature on the adsorption of lead by an activated carbon from coconut shells is investigated. The pseudo second order equation is applied to the kinetic data obtained at different temperatures in order to determine the adsorption rate constants at these temperatures. Then, the Arrhenius equation is applied to the rate constants to determine the activation energy of the sorption reaction and the pre-exponential factor. By applying the Eyring equation to the rate constants, the standard thermodynamic activation parameters of the sorption reaction can also be calculated. In addition, the isotherms of lead adsorption on the activated carbon from coconut shells, at different temperatures, are determined and fitted by the Langmuir equation. The Van’t Hoff equation is applied to the Langmuir equilibrium constants in order to determine the standard enthalpy of the sorption reaction. The other standard thermodynamic parameters<br />(Gibbs standard enthalpy and standard entropy) are deduced. The isosteric standard sorption enthalpy is also determined by using both the classical approach and an adapted Clausius Clapeyron equation. The results are identical. The value obtained is higher, but more correct than that of Langmuir. On the basis of these<br />thermokinetic parameters, the activated carbon from Coconut shells can be considered as a very efficient carbon for the sorption of lead and its sorption efficiency (rate and quantity) increase with the temperature.

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The Solubility and Hydrolysis of Aqueous Aluminium Hydroxides in Dilute Fresh Waters at Different Temperatures

Hydrology Research ◽

10.2166/nh.1990.0015 ◽

1990 ◽

Vol 21 (3) ◽

pp. 195-204 ◽

Cited By ~ 33

Author(s):

Espen Lydersen

Keyword(s):

Natural Waters ◽

Equilibrium Constants ◽

Relative Concentration ◽

Amorphous Solid ◽

Effect Of Temperature ◽

Natural Soil ◽

Exchange Reactions ◽

Organic Complexes ◽

Inorganic Species ◽

Different Temperatures

This study is mainly focusing on the effect of temperature and pH on the chemistry of Al(OH)3(s) using available thermodynamic data. The calculations show that a doubling of the [H+] or a decrease in temperature by 15°C, approximately yields the same solubility increase of the various Al(OH)3(s) presented. The relative concentration of aqueous aluminium hydrolysis complexes is also highly temperature dependent. At 25°C and pH 5, the calculated distribution of dissolved, inorganic aluminium hydroxides corresponds to about 36% of Al3+, 37 % of Al(OH)2+, 26 % of Al(OH)2+ and 1 % of Al(OH)30. At the same pH but at 0°C, about 84%, 13%, 2% and 0% are present as Al3+, Al(OH)2+, Al(OH)2+ and Al(OH)30, respectively. This temperature effect is of major importance as the hydroxide species are supposed to be the most toxic species to aquatic biota. Literature reports on the equilibrium constants Al(OH)3(s), log*Ks, vary from about 8 to 11, a variation in the product by a factor of 1000. In natural soil/water systems the solubility products of crystalline and amorphous solid aluminium sources are unknown and the solubility may also be coupled to combined weathering/ion exchange processes. In addition substantial amount of aluminium may be present as organic complexes where aluminium by cation exchange reactions may enter the solution as monomeric inorganic species. Thus, if a low value for the equilibrium constants of Al(OH)3(s) is used as reference when calculating the degree of aluminium saturation, an apparent oversaturation will often be demonstrated. To estimate the degree of aluminium saturation in natural waters whould therefore only be of theoretical interest.

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Adsorption of nucleic acid constituent uracil on copper(II)-loaded, solid peat and soil-derived humic acids

Canadian Journal of Soil Science ◽

10.4141/s00-066 ◽

2001 ◽

Vol 81 (3) ◽

pp. 309-316

Author(s):

E A Ghabbour ◽

G. Davies ◽

R L Dunfee ◽

N A Smith ◽

M E Vozzell

Keyword(s):

Nucleic Acid ◽

New Hampshire ◽

Humic Acids ◽

Metal Binding ◽

Opposite Effect ◽

Coordination Numbers ◽

Enthalpy And Entropy Changes ◽

Solute Interactions ◽

Enthalpy And Entropy ◽

Binding Enthalpy

Humic acids (HA) in compost, peats and soils sorb organic compounds selectively. This paper investigates the micro- and macroscopic properties of solid HAs isolated from a German peat (GHA) and a New Hampshire soil (NHA) using tightly bound copper(II) and nucleic acid constituent uracil adsorption as analytical probes. Isotherm measurements at 5.0–35.0°C show that tightly bound Cu(II) decreases the amount of uracil adsorbed by GHA at mM or lower uracil concentrations whereas previous work revealed the opposite effect for bound Hg(II). Site capacity comparisons are consistent with lower coordination numbers for HA-bound Hg(II) than for HA-bound Cu(II). Low coordination numbers leave Hg(II) sites open for uracil binding. Enthalpy and entropy changes for uracil adsorption on GHA, NHA, their Cu(II) and Hg(II)-loaded forms and on compost-derived HA are linearly correlated, indicating that HAs are free energy buffers. Water and bound metals evidently play major roles in HA-solute interactions and in HA aggregation/disaggregation. Key words: Humic acids, metal binding, nucleic acid constituents, uracil, adsorption, isotherms, thermodynamics

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The Respiration of some Planktonic copepods II. The Effect Of Temperature

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400011607 ◽

1953 ◽

Vol 31 (3) ◽

pp. 447-460 ◽

Cited By ~ 28

Author(s):

D. T. Gauld ◽

J. E. G. Raymont

Keyword(s):

Respiratory Rate ◽

The Body ◽

The Other ◽

Effect Of Temperature ◽

Acartia Clausi ◽

Temora Longicornis ◽

Different Temperatures ◽

Planktonic Copepods ◽

The Difference ◽

The Relationship

The respiratory rates of three species of planktonic copepods, Acartia clausi, Centropages hamatus and Temora longicornis, were measured at four different temperatures.The relationship between respiratory rate and temperature was found to be similar to that previously found for Calanus, although the slope of the curves differed in the different species.The observations on Centropages at 13 and 170 C. can be divided into two groups and it is suggested that the differences are due to the use of copepods from two different generations.The relationship between the respiratory rates and lengths of Acartia and Centropages agreed very well with that previously found for other species. That for Temora was rather different: the difference is probably due to the distinct difference in the shape of the body of Temora from those of the other species.The application of these measurements to estimates of the food requirements of the copepods is discussed.

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Effect of temperature, CO2 and O2 on motility and mobility of Anisakidae larvae

Scientific Reports ◽

10.1038/s41598-021-83505-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Aiyan Guan ◽

Inge Van Damme ◽

Frank Devlieghere ◽

Sarah Gabriël

Keyword(s):

Enzymatic Digestion ◽

Infected Fish ◽

Effect Of Temperature ◽

Video Recordings ◽

Different Temperatures ◽

Semi Solid ◽

Zoonotic Parasites ◽

The Impact ◽

Phosphate Buffered Saline

AbstractAnisakidae, marine nematodes, are underrecognized fish-borne zoonotic parasites. Studies on factors that could trigger parasites to actively migrate out of the fish are very limited. The objective of this study was to assess the impact of different environmental conditions (temperature, CO2 and O2) on larval motility (in situ movement) and mobility (migration) in vitro. Larvae were collected by candling or enzymatic digestion from infected fish, identified morphologically and confirmed molecularly. Individual larvae were transferred to a semi-solid Phosphate Buffered Saline agar, and subjected to different temperatures (6 ℃, 12 ℃, 22 ℃, 37 ℃) at air conditions. Moreover, different combinations of CO2 and O2 with N2 as filler were tested, at both 6 °C and 12 °C. Video recordings of larvae were translated into scores for larval motility and mobility. Results showed that temperature had significant influence on larval movements, with the highest motility and mobility observed at 22 ℃ for Anisakis spp. larvae and 37 ℃ for Pseudoterranova spp. larvae. During the first 10 min, the median migration of Anisakis spp. larvae was 10 cm at 22 ℃, and the median migration of Pseudoterranova spp. larvae was 3 cm at 37 ℃. Larval mobility was not significantly different under the different CO2 or O2 conditions at 6 °C and 12 ℃. It was concluded that temperature significantly facilitated larval movement with the optimum temperature being different for Anisakis spp. and Pseudoterranova spp., while CO2 and O2 did not on the short term. This should be further validated in parasite-infected/spiked fish fillets.

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Impact of Deuteration and Temperature on Furan Ring Dynamics

Molecules ◽

10.3390/molecules26102889 ◽

2021 ◽

Vol 26 (10) ◽

pp. 2889

Author(s):

Przemyslaw Dopieralski ◽

Iryna V. Omelchenko ◽

Zdzislaw Latajka

Keyword(s):

Conformational Changes ◽

Furan Ring ◽

Computational Studies ◽

Significant Progress ◽

Dynamic Simulations ◽

Cyclic Molecules ◽

Ring Dynamics ◽

Different Temperatures ◽

Long Time ◽

Shape And Size

Despite significant progress in conformational analysis of cyclic molecules, the number of computational studies is still limited while most of that available in the literature data have been obtained long time ago with outdated methods. In present research, we have studied temperature driven conformational changes of the furan ring at three different temperatures. Additionally, the effect of deuteration on the ring dynamics is discussed; in addition, the aromaticity indices following the Bird and HOMA schemes are computed along all trajectories. Our ab initio molecular dynamic simulations revealed that deuteration has changed the furan ring dynamics and the obvious consequences; in addition, the shape and size of molecule are expected to be different.

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Effect of Temperature during Drying and Storage of Dried Figs on Growth, Gene Expression and Aflatoxin Production

Toxins ◽

10.3390/toxins13020134 ◽

2021 ◽

Vol 13 (2) ◽

pp. 134

Author(s):

Ana Isabel Galván ◽

Alicia Rodríguez ◽

Alberto Martín ◽

Manuel Joaquín Serradilla ◽

Ana Martínez-Dorado ◽

...

Keyword(s):

Gene Expression ◽

Aflatoxin Production ◽

Effect Of Temperature ◽

Mycotoxin Production ◽

Industrial Processing ◽

Factors Associated ◽

Different Temperatures ◽

Major Producer ◽

Main Factors ◽

And Storage

Dried fig is susceptible to infection by Aspergillus flavus, the major producer of the carcinogenic mycotoxins. This fruit may be contaminated by the fungus throughout the entire chain production, especially during natural sun-drying, post-harvest, industrial processing, storage, and fruit retailing. Correct management of such critical stages is necessary to prevent mould growth and mycotoxin accumulation, with temperature being one of the main factors associated with these problems. The effect of different temperatures (5, 16, 25, 30, and 37 °C) related to dried-fig processing on growth, one of the regulatory genes of aflatoxin pathway (aflR) and mycotoxin production by A. flavus, was assessed. Firstly, growth and aflatoxin production of 11 A. flavus strains were checked before selecting two strains (M30 and M144) for in-depth studies. Findings showed that there were enormous differences in aflatoxin amounts and related-gene expression between the two selected strains. Based on the results, mild temperatures, and changes in temperature during drying and storage of dried figs should be avoided. Drying should be conducted at temperatures >30 °C and close to 37 °C, while industry processing, storage, and retailing of dried figs are advisable to perform at refrigeration temperatures (<10 °C) to avoid mycotoxin production.

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