scholarly journals Response of a first-order stream in Maine to short-term in-stream acidification

2000 ◽  
Vol 4 (3) ◽  
pp. 383-391 ◽  
Author(s):  
S. A. Norton ◽  
R. Wagai ◽  
T. Navratil ◽  
J. M. Kaste ◽  
F. A. Rissberger
Keyword(s):  
Ion Exchange ◽  
Stream Water ◽  
Base Cations ◽  
Exchange Capacity ◽  
Short Term ◽  
Ph Change ◽  
Order Stream ◽  
First Order ◽  
Stream Acidification ◽  
Ph Range

Abstract. An experimental short-term acidification with HCl at a first-order stream in central Maine, USA was used to study processes controlling the changes in stream chemistry and to assess the ability of stream substrate to buffer pH. The streambed exerted a strong buffering capacity against pH change by ion exchange during the 6-hour acidification. Streambed substrates had substantial cation and anion exchange capacity in the pH range of 4.1 to 6.5. The ion exchange for cations and SO42- were rapid and reversible. The speed of release of cations from stream substrates was Na1+> Ca2+ > Mg2+ > Aln+ > Be2+, perhaps relating to charge density of these cations. Ca2+ desorption dominated neutralisation of excess H+ for the first 2 hr. As the reservoir of exchangeable Ca diminished, desorption (and possibly dissolution) of Al3+ became the dominant neutralising mechanism. The exchangeable (and possibly soluble) reservoir of Al was not depleted during the 6-hour acidification. Sulphate adsorption during the acidification reduced the concentration of SO42- in stream water by as much as 20 μeq L-1 (from 70 μeq L-1). Desorption of SO42- and adsorption of base cations after the artificial acidification resulted in a prolongation of the pH depression. The streambed had the capacity to buffer stream water chemistry significantly during an acidifying event affecting the entire upstream catchment. Keywords: stream acidification; ion exchange; sediment; sulfate exchange; aluminium; beryllium

Ecology of juvenile Northern watersnakes (Nerodia sipedon) inhabiting low-order streams

2010 ◽  
Vol 31 (2) ◽  
pp. 169-174 ◽  
Author(s):  
Kristen Cecala ◽  
Michael Dorcas ◽  
Steven Price
Keyword(s):  
North Carolina ◽  
Natural History ◽  
Stream Water ◽  
Juvenile Stage ◽  
Nerodia Sipedon ◽  
Order Stream ◽  
First Order ◽  
High Survivorship ◽  
History Of ◽  
Low Order

AbstractThe juvenile stage for many reptiles is considered “the lost years” because of low capture probabilities, however understanding factors impacting juvenile survivorship and recruitment is critical for conservation of populations. We studied the ecology of juvenile Northern watersnakes, Nerodia sipedon, by intensively sampling a first-order stream and determined the occupancy of juveniles in 30 low-order streams in the Piedmont of North Carolina. Juveniles were relatively abundant within a single stream (n = 62 ± 9), and their capture probabilities were positively related to increasing stream-water temperatures. We also found that juveniles had high survivorship (ϕ = 0.87 ± 0.017). Occupancy of juvenile N. sipedon in low-order, Piedmont streams may be greater at streams that have confluences with high order streams or lakes, which potentially support adult N. sipedon populations. This study provides important information regarding the natural history of juvenile reptiles and indicates the importance of low order streams as habitat for N. sipedon populations.

Seasalt Effects on the Acid Neutralizing Capacity of Streamwaters in Southern Norway

1995 ◽  
Vol 26 (4-5) ◽  
pp. 369-388 ◽  
Author(s):  
Espen Lydersen ◽  
Arne Henriksen
Keyword(s):  
Stream Water ◽  
Base Cations ◽  
Acid Neutralizing Capacity ◽  
Neutral Salt ◽  
Exchange Reactions ◽  
Short Term ◽  
Sulphur Compounds ◽  
Neutralizing Capacity ◽  
Southern Norway

Input of neutral salt, primarily NaCl, from sea spray is an important factor for short-term acidification of surface water, primarily in already acidified areas, because Na may substitute for H+ and cationic aluminium by cation-exchange reactions in the soil. By evaluating the variation of non-marine sodium (Na*) separately it is possible to estimate the major effect of seasalt episodes on the neutralizing capacity (ANC) of stream water. At four long-term monitored Norwegian catchments, the Na* in stream water on average explained 28 ± 4% of the monthly variations of ANC in stream water at Birkenes, and 27 ± 3%, 20 ± 2% and 56 ± 5% of the correspondent variations at Storgama, Langtjern and Kaarvatn, during the respective monitoring periods. The remaining variations in acid neutralizing capacity are explained by the difference between non-marine base cations (ΣCa*,Mg*,K*) and non-marine sulphate (SO4*) and NO3. This paper also indicates that seasalt episodes are probably of greater importance for the periodic variations in ANC of stream water than commonly recognized. During the last years, extreme seasalt episodes have occurred in southern Norway, and more frequently at winter-time, which means that seasalt inputs have played a more important role for the short-term variations of ANC in stream water the last years. This tendency is also strengthened by the fact that there has been a significant decline in the input of acidic sulphur compounds and non-marine base cations in stream water during the last 10-15 years. Because the decline in soil-derived base cations in stream water is somewhat lower than the correspondent decline of sulphate, a slowly improving ANC of stream water should be expected on long-term basis. Seasalt episodes of the same magnitude as those present during the last years, will therefore most likely cause less extreme water-chemical conditions in the years to come. Because the seasalt effect seems to be a short-term effect, there is no reason to claim that these effects may cause long-term acidification, a conclusion earlier drawn from several correspondent studies.

scholarly journals Investigate the adsorption of cesium ion (Cs+) on Zn2[Fe(CN)6] AND Zn3[Fe(CN)6]2 nanoparticles

2020 ◽  
Vol 3 (4) ◽  
pp. 307-316
Author(s):  
Nguyen Dinh Trung ◽  
Le Thi Ha Lan ◽  
Truong Dong Phuong
Keyword(s):  
Ion Exchange ◽  
Adsorption Capacity ◽  
Exchange Capacity ◽  
Ion Concentration ◽  
Experimental Conditions ◽  
Ion Exchange Capacity ◽  
Freundlich Isotherms ◽  
Ion Absorption ◽  
Adsorption Data ◽  
Ph Range

Adsorption of Cs+ ion from aqueous solution by Zn2[Fe(CN)6] and Zn3[Fe(CN)6]2 nanoparticle, and the effect of experimental conditions on the adsorption were investigated. Preliminary results showed that two materials were very efficient as an absorbent. Zn2[Fe(CN)6] and Zn3[Fe(CN)6]2 nanoparticle adsorbents for removal Cs+ion from solution have been successfully synthesized. Comparison between two materials, the Cs + ion adsorption capacity of Zn2[Fe(CN)6] was higher than Zn3[Fe(CN)6]2 and the reaction time was shorter. The adsorption equilibrium time of Zn3[Fe(CN)6]2 was about 20 hours, and the suitable pH range 3-7 while the Zn2[Fe(CN)6] was 15 minutes. The Cs+ ion absorption by Zn2[Fe(CN)6] nanoparticle follow the ion exchange mechanism, the best exchange capacities of the material were in the pH 3-5 range, ion exchange capacity depended on the pH, the maximum ion exchange capacity of the material at pH = 4 was 1.01 meq (Cs+) / g. After 15 min, about 98% of initial Cs+ ion concentration was removed from the solution; the adsorption data did not accord with Langmuir and Freundlich isotherms. The high adsorption capacity and good performance on other aspects, make the Zn2[Fe(CN)6] nanoparticle a promising adsorbent for the removal of Cs+ ion from water.

scholarly journals Studies of acid deposition and its effects in two small catchments in Hunan, China

2003 ◽  
Vol 7 (3) ◽  
pp. 399-410 ◽  
Author(s):  
N. Xue ◽  
H. M. Seip ◽  
B. Liao ◽  
R. D. Vogt
Keyword(s):  
Soil Water ◽  
Acid Deposition ◽  
Wet Deposition ◽  
Stream Water ◽  
Weighted Average ◽  
Base Cations ◽  
Exchange Capacity ◽  
Provincial Capital ◽  
Southern Hunan

Abstract. Acid deposition and its effects were studied by analysing the chemistry in precipitation, stream water, soil water and soils in two catchments in Hunan. One site, Linkesuo (denoted LKS), is on the outskirts of Changsha, the provincial capital of Hunan, the other (Bailutang, denoted BLT) on the outskirts of Chenzhou in southern Hunan. Volume-weighted average pH values and sulphate concentrations in wet deposition were 4.58 (BLT) and 4.90 (LKS) and 174 μmolc L-1 and 152 μmolc L-1, respectively. Wet deposition of sulphate has been estimated as 4.3 gS m-2yr-1 and 3.4 gS m-2yr-1 at BLT and LKS, respectively. Estimates of the corresponding total depositions (dry + wet) are 6.1 gS m-2yr-1 and 5.3 gS m-2yr-1. In precipitation and throughfall, sulphate was the major anion and calcium the major cation. In stream and soil water, nitrate was slightly higher than sulphate on an equivalent basis and magnesium (Mg) not much lower than calcium (Ca). Important soil properties, such as soil pH, soil organic matter (SOM) content, exchangeable acidic cations, exchangeable base cations, effective cation exchange capacity (CECe), base saturation (BS), and aluminium (Al) and iron (Fe) pools, were determined for five forest soil profiles (consisting of four horizons) in each of the two catchments. The soils in BLT are generally more acid, have lower BS and higher Al and Fe pools than the LKS soils. The Al- and Fe-pools were generally higher in the topsoils (i.e. the O and A horizons) than in deeper soils (i.e. E and B horizons) especially at the most acidic site (BLT). There are significant correlations between Fe-pools and the corresponding Al-pools in both catchments except between the amorphous Feox and Alox. Considering the long-term high deposition of sulphate, there is a risk of future ecological damage due to acidification, especially in the BLT catchment, although vegetation damage has yet to be observed in the catchments. This condition appears to be representative of a large part of Hunan. Keyword: acid deposition, soil acidification, catchment, Al-pools, Fe-pools, Hunan

scholarly journals Removal of quaternary ammonium compounds in ion exchange process

2019 ◽  
Vol 116 ◽  
pp. 00034
Author(s):  
Aleksandra Klimonda ◽  
Izabela Kowalska
Keyword(s):  
Ion Exchange ◽  
Cationic Surfactant ◽  
Exchange Process ◽  
Exchange Capacity ◽  
Resin Matrix ◽  
Ph Change ◽  
Ion Exchange Process ◽  
Batch Tests ◽  
Exchange Resins ◽  
Surfactant Removal

The study attempted to evaluate the effectiveness of ion exchange process in cationic surfactant (benzalkonium chloride, BAC) removal from model solutions. Four commercial cation-exchange resins were chosen for the batch tests in four doses (2.5–20 mL L-1). The experiments included evaluation of the following parameters on ion exchange efficiency: resin characteristics and dose, presence of inorganic salt and pH of treated solution. The ion exchange process was found to be very effective in cationic surfactant removal – two of tested resins allowed to remove up to 80% of contaminant after contact time of 40 minutes, the last two – after 60 minutes of mixing in all range of doses. The presence of electrolyte neither pH change has no essential effect on surfactant removal efficiency. The analysis of the ion exchange isotherms showed that the strongly-acidic macroporous resin C150 H was characterized by the highest BAC ion exchange capacity (153.8 mg mL-1), while the weakly-acidic gel resin C104 showed the best affinity of the exchanged ions to the resin matrix.

Kinetic of oxidation of methyl orange by vanadium(V) under conditions VO2+ and decavanadates coexist: Catalysis by Triton X-100 micellar medium

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Methyl Orange ◽  
Solution Ph ◽  
Vanadium Concentration ◽  
Limiting Behavior ◽  
First Order ◽  
First Order Kinetics ◽  
Ph Range ◽  
Kinetic Pattern ◽  
Triton X ◽  
Kinetics Of

The kinetics of oxidation of methyl orange by vanadium(V) {V(V)} has been investigated in the pH range 2.3-3.79. In this pH range V(V) exists both in the form of decavanadates and VO2+. The kinetic results are distinctly different from the results obtained for the same reaction in highly acidic solution (pH < 1) where V(V) exists only in the form of VO2+. The reaction obeys first order kinetics with respect to methyl orange but the rate has very little dependence on total vanadium concentration. The reaction is accelerated by H+ ion but the dependence of rate on [H+] is less than that corresponding to first order dependence. The equilibrium between decavanadates and VO2+ explains the different kinetic pattern observed in this pH range. The reaction is markedly accelerated by Triton X-100 micelles. The rate-[surfactant] profile shows a limiting behavior indicative of a unimolecular pathway in the micellar pseudophase.

Soil and Stream Water Chemistry During Spring Snowmelt

1992 ◽  
Vol 23 (1) ◽  
pp. 13-26 ◽  
Author(s):  
W. H. Hendershot ◽  
L. Mendes ◽  
H. Lalande ◽  
F. Courchesne ◽  
S. Savoie
Keyword(s):  
Stream Water ◽  
Base Cations ◽  
Stream Chemistry ◽  
Stream Water Chemistry ◽  
The Matrix ◽  
Adsorption Desorption ◽  
The Relationship ◽  
Best Fit ◽  
Spring Snowmelt ◽  
Over Time

In order to determine how water flowpath controls stream chemistry, we studied both soil and stream water during spring snowmelt, 1985. Soil solution concentrations of base cations were relatively constant over time indicating that cation exchange was controlling cation concentrations. Similarly SO4 adsorption-desorption or precipitation-dissolution reactions with the matrix were controlling its concentrations. On the other hand, NO3 appeared to be controlled by uptake by plants or microorganisms or by denitrification since their concentrations in the soil fell abruptly as snowmelt proceeded. Dissolved Al and pH varied vertically in the soil profile and their pattern in the stream indicated clearly the importance of water flowpath on stream chemistry. Although Al increased as pH decreased, the relationship does not appear to be controlled by gibbsite. The best fit of calculated dissolved inorganic Al was obtained using AlOHSO4 with a solubility less than that of pure crystalline jurbanite.

Equilibrium Sorptions in Heterogeneous Ion Exchange Membranes

1992 ◽  
Vol 57 (9) ◽  
pp. 1905-1914
Author(s):  
Miroslav Bleha ◽  
Věra Šumberová
Keyword(s):  
Experimental Data ◽  
Ion Exchange ◽  
Total Content ◽  
Distribution Coefficients ◽  
Exchange Capacity ◽  
Ion Exchange Membranes ◽  
Ion Exchange Capacity ◽  
Equilibrium Sorption ◽  
Inhomogeneity Factor

The equilibrium sorption of uni-univalent electrolytes (NaCl, KCl) in heterogeneous cation exchange membranes with various contents of the ion exchange component and in ion exchange membranes Ralex was investigated. Using experimental data which express the concentration dependence of equilibrium sorption, validity of the Donnan relation for the systems under investigation was tested and values of the Glueckauf inhomogeneity factor for Ralex membranes were determined. Determination of the equilibrium sorption allows the effect of the total content of internal water and of the ion-exchange capacity on the distribution coefficients of the electrolyte to be determined.

Kinetics and mechanism of the reaction between oxidized cytochrome c and ascorbic acid

1991 ◽  
Vol 56 (2) ◽  
pp. 478-490 ◽  
Author(s):  
Joaquin F. Perez-Benito ◽  
Conchita Arias
Keyword(s):  
Ascorbic Acid ◽  
Cytochrome C ◽  
Redox Reactions ◽  
Arrhenius Equation ◽  
Horse Heart Cytochrome ◽  
First Order ◽  
Acidic Form ◽  
Ph Range ◽  
Horse Heart Cytochrome C ◽  
Mechanism Of The Reaction

The reaction between horse-heart cytochrome c and ascorbic acid has been investigated in the pH range 5.5 – 7.1 and at 10.0 – 25.0 °C. The rate shows a first-order dependence on the concentration of cytochrome c, it increases in a non-linear way as the concentration of ascorbic acid increases, it increases markedly with increasing pH and, provided that the ionic strength of the medium is high enough, it fulfills the Arrhenius equation. The apparent activation energy increases as the pH of the solution increases. The results have been explained by means of a mechanism that includes the existence of an equilibrium between two forms (acidic and basic) of oxidized cytochrome c: cyt-H+ -Fe3+ + OH- cyt -Fe3+ + H2O, whose equilibrium constant is (6.7 ± 1.4). 108 at 25.0 °C, the acidic form being more reducible than the basic one. It is suggested that there is a linkage of hydrogenascorbate ion to both forms of cytochrome c previous to the redox reactions. Two possibilities for the oxidant-reductant linkage (binding and adsorption) are discussed in detail.

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