Soil Adsorption Phenomena

2016 ◽  
Author(s):  
Garrison Sposito
Keyword(s):  
Aqueous Solution ◽  
Soil Column ◽  
Batch Process ◽  
Side Reactions ◽  
Soil Slurry ◽  
Soil Adsorption ◽  
Flow Through ◽  
Dry Soil ◽  
Excess Number ◽  
Supernatant Solution

Adsorption experiments involving soil particles typically are performed in a sequence of three steps: (1) reactio of an adsorptive (ion or molecule) with a soil contacting an aqueous solution of known composition under controlled temperature and applied pressure for a prescribed period of time, (2) separationof the wet soil slurry from the supernatant aqueous solution, and (3) quantitationof the ion or molecule of interest, both in the aqueous solution and in the separated soil slurry along with its entrained soil solution. The reaction step can be performed in either a closed system (batch reactor) or an open system (flow-through reactor), and it can proceed over a time period that is either relatively short (to investigate adsorption kinetics) or very long (to investigate adsorption equilibration). The separation step is similarly open to choice, with centrifugation, filtration, or gravitational settling being conventional methods to achieve separation. The quantitation step, in principle, should be designed not only to determine the moles of adsorbate and unreacted adsorptive, but also to verify whether unwanted side reactions, such as precipitation of the adsorptive or dissolution of the adsorbent, have influenced the experiment. After reaction between an adsorptive i and a soil adsorbent, the moles of i adsorbed per kilogram of dry soil is calculated with the standard equation ni ≡ niT − Mwmi where niT is the total moles of species i per kilogram dry soil in a slurry (batch process) or a soil column (flow-through process), Mw is the gravimetric water content of the slurry or soil column (measured in kilograms water per kilogram dry soil), and mi is the molality (moles per kilogram water) of species i in the supernatant solution (batch process) or effluent solution (flow-through process). Equation 8.1 defines the surface exces, ni, of an ion or molecule adsorptive that has become an adsorbate. Formally, ni is the excess number of moles of i per kilogram soil relative to its molality in the supernatant solution. As mentioned in Section 7.2, this surface excess may be a positive, zero, or negative quantity.

Relationship between the formation of flow paths and elution behavior with water flow through the soil column

2021 ◽  
Author(s):  
Kyouhei Tsuchida ◽  
Kengo Nakamura ◽  
Monami Kondo ◽  
Noriaki Watanabe ◽  
Takeshi Komai
Keyword(s):  
Aqueous Solution ◽  
Transport Phenomenon ◽  
Soil Column ◽  
Flow Path ◽  
Column Tests ◽  
Flow Paths ◽  
X Ray ◽  
Elution Behavior ◽  
Flow Through ◽  
The Relationship

<p>The transport phenomenon of pollutants in soil is complicated because of the formation of the flow path in soil. In this study, the relationship between the flow path in the soil and the elution behavior of various components was evaluated by the column tests with different filling methods to change the flow path in the column. The flow path in the column was visualized by using potassium iodide aqueous solution and X-ray CT. Our result shows that the elution behavior of the easily eluted components was not significantly affected by the flow path in the column. In addition, the cation more eluted when the flow path spread throughout the column than when the flow path was intensive. This suggests that eluted components may be affected by anions in soil. From these results, it was found that the elution behavior of components is influenced by the flow path in the column and some were not, and when it was influenced, the degree of influence is different depending on the components.</p>

Reactions in Activated Peroxide Systems and their Influences on Bleaching Performance

2020 ◽  
Vol 17 ◽  
Author(s):  
Xiaoyan Wang ◽  
Jinmei Du ◽  
Changhai Xu
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Energy Efficiency ◽  
Textile Industry ◽  
High Energy ◽  
Side Reactions ◽  
Competitive Reactions ◽  
High Energy Efficiency ◽  
Hydrolysis Of ◽  
Bleach Activators

Abstract:: Activated peroxide systems are formed by adding so-called bleach activators to aqueous solution of hydrogen peroxide, developed in the seventies of the last century for use in domestic laundry for their high energy efficiency and introduced at the beginning of the 21st century to the textile industry as an approach toward overcoming the extensive energy consumption in bleaching. In activated peroxide systems, bleach activators undergo perhydrolysis to generate more kinetically active peracids that enable bleaching under milder conditions while hydrolysis of bleach activators and decomposition of peracids may occur as side reactions to weaken the bleaching efficiency. This mini-review aims to summarize these competitive reactions in activated peroxide systems and their influence on bleaching performance.

scholarly journals Perchlorate and Agriculture on Mars

Soil Systems ◽  
2021 ◽  
Vol 5 (3) ◽  
pp. 37
Author(s):  
Christopher Oze ◽  
Joshua Beisel ◽  
Edward Dabsys ◽  
Jacqueline Dall ◽  
Gretchen North ◽  
...  
Keyword(s):  
Plant Growth ◽  
Soil Column ◽  
Metal Availability ◽  
Metal Release ◽  
High Solubility ◽  
Plant Life ◽  
Growing Medium ◽  
Successful Removal ◽  
Flow Through ◽  
Martian Regolith

Perchlorate (ClO4−) is globally enriched in Martian regolith at levels commonly toxic to plants. Consequently, perchlorate in Martian regolith presents an obstacle to developing agriculture on Mars. Here, we assess the effect of perchlorate at different concentrations on plant growth and germination, as well as metal release in a simulated Gusev Crater regolith and generic potting soil. The presence of perchlorate was uniformly detrimental to plant growth regardless of growing medium. Plants in potting soil were able to germinate in 1 wt.% perchlorate; however, these plants showed restricted growth and decreased leaf area and biomass. Some plants were able to germinate in regolith simulant without perchlorate; however, they showed reduced growth. In Martian regolith simulant, the presence of perchlorate prevented germination across all plant treatments. Soil column flow-through experiments of perchlorate-containing Martian regolith simulant and potting soil were unable to completely remove perchlorate despite its high solubility. Additionally, perchlorate present in the simulant increased metal/phosphorous release, which may also affect plant growth and biochemistry. Our results support that perchlorate may modify metal availability to such an extent that, even with the successful removal of perchlorate, Martian regolith may continue to be toxic to plant life. Overall, our study demonstrates that the presence of perchlorate in Martian regolith provides a significant challenge in its use as an agricultural substrate and that further steps, such as restricted metal availability and nutrient enrichment, are necessary to make it a viable growing substrate.

scholarly journals Removal of Chromium from Aqueous Solution Using Modified Pomegranate Peel:Mechanistic and Thermodynamic Studies

2009 ◽  
Vol 6 (s1) ◽  
pp. S153-S158 ◽  
Author(s):  
Tariq S. Najim ◽  
Suhad A. Yassin
Keyword(s):  
Activation Energy ◽  
Solid Solution ◽  
Aqueous Solution ◽  
Adsorption Process ◽  
Batch Process ◽  
The Other ◽  
Water Molecules ◽  
Pomegranate Peel ◽  
Solution Interface ◽  
Adsorbent Surface

Modified pomegranate peel (MPGP) and formaldehyde modified pomegranate peel (FMPGP) were prepared and used as adsorbent for removal of Cr(VI) ions from aqueous solution using batch process. The temperature variation study of adsorption on both adsorbents revealed that the adsorption process is endothermic, from the positive values of ∆H˚. These values lie in the range of physisorption. The negative values of ∆G˚ show the adsorption is favorable and spontaneous. On the other hand, these negative values increases with increase in temperature on both adsorbents, which indicate that the adsorption is preferable at higher temperatures. ∆S˚ values showed that the process is accompanied by increase in disorder and randomness at the solid solution interface due to the reorientation of water molecules and Cr(VI) ions around the adsorbent surface. The endothermic nature of the adsorption was also confirmed from the positive values of activation energy, Ea, the low values of Ea confirm the physisorption mechanism of adsorption. The sticking probability, S*, of Cr(VI) ion on surface of both adsorbents showed that the adsorption is preferable due to low values of S*(0< S*< 1 ), but S*values are lower for FMPGP indicating that the adsorption on FMPGP is more preferable .

scholarly journals Removal of Metanil Yellow by Batch Biosorption from Aqueous Phase on Egg Membrane: Equilibrium and Isotherm Studies

2019 ◽  
Vol 2 (04) ◽  
pp. 15-26
Author(s):  
Beniah Obinna Isiuku ◽  
Francis Chizoruo Ibe
Keyword(s):  
Aqueous Solution ◽  
Correlation Coefficients ◽  
Batch Process ◽  
Solution Concentration ◽  
Isotherm Models ◽  
Egg Membrane ◽  
Metanil Yellow ◽  
Batch Biosorption ◽  
Best Fit ◽  
Hen Egg

The biosorption of metanil yellow on hen egg membrane from aqueous solution in a batch process was investigated at 29oC with a view to determine the potential of the membrane in removing metanil yellow from aqueous solution.  The effects of contact time, initial biosorbate concentration, biosorbent dosage and initial biosorbate pH were determined. Various isotherm models were used to analyze experimental data. The highest experimental equilibrium biosorption capacity obtained was 129.88 mg/g. The optimum pH was 3. Adsorption capacity increased with increase in initial solution concentration but decreased with increase in time. The isotherm models applied were good fits based on correlation coefficients. Flory-Huggins isotherm was the best fit (R2 0.986). The biosorption was endothermic, good, physisorptive and spontaneous. This work shows that hen egg membrane is a potential biosorbent for the removal of metanil yellow from aqueous solution.

scholarly journals Biosorption of Lead Ions from Aqueous Solution UsingFicus benghalensisL.

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Venkateswara Rao Surisetty ◽  
Janusz Kozinski ◽  
L. Rao Nageswara
Keyword(s):  
Aqueous Solution ◽  
Process Parameters ◽  
Contact Time ◽  
Batch Process ◽  
Ion Concentration ◽  
Lead Ions ◽  
Lead Ion ◽  
Maximum Adsorption Capacity ◽  
Ficus Benghalensis ◽  
Leaf Powder

Ficus benghalensisL., a plant-based material leaf powder, is used as an adsorbent for the removal of lead ions from aqueous solution using the biosorption technique. The effects of process parameters such as contact time, adsorbent size and dosage, initial lead ion concentration, and pH of the aqueous solution on bio-sorption of lead byFicus benghalensisL. were studied using batch process. The Langmuir isotherm was more suitable for biosorption followed by Freundlich and Temkin isotherms with a maximum adsorption capacity of 28.63 mg/g of lead ion on the biomass ofFicus benghalensisL. leaves.

Insights into naphthalene degradation in aqueous solution and soil slurry medium: Performance and mechanisms

Chemosphere ◽  
2021 ◽  
pp. 132761
Author(s):  
Guilu Zeng ◽  
Rumin Yang ◽  
Zhengyuan Zhou ◽  
Jingyao Huang ◽  
Muhammad Danish ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Soil Slurry ◽  
Naphthalene Degradation

Movement of Aldolase From Excised Rat Diaphragm

1956 ◽  
Vol 185 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Kenneth L. Zierler
Keyword(s):  
Aqueous Solution ◽  
Cell Membrane ◽  
Potassium Concentration ◽  
Fiber Surface ◽  
Rat Diaphragm ◽  
High Potassium ◽  
Flow Through ◽  
High Potassium Concentration

A protein, aldolase, flows from excised rat diaphragm incubated in a variety of media. The rate of outflow of aldolase is increased by anoxia and by a high potassium concentration in the medium, and it is decreased by a reduction in temperature and by addition of glucose. When diaphragm is transferred to fresh media and reincubated the rate of outflow of aldolase is also accelerated. From measurements of rates of outflow of aldolase, estimates have been made of the area of the membrane required for aldolase to flow through the cell membrane as though it were flowing simply through an aqueous solution. This area is about 10–7–10–8 of the estimated total fiber surface. The estimated area for diffusion of aldolase is modified 16-fold by factors which alter the metabolism of diaphragm.

scholarly journals Hydrogenation of Aqueous Acetic Acid over Ru-Sn/TiO2 Catalyst in a Flow-Type Reactor, Governed by Reverse Reaction

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1270
Author(s):  
Yuanyuan Zhao ◽  
Kansei Konishi ◽  
Eiji Minami ◽  
Shiro Saka ◽  
Haruo Kawamoto
Keyword(s):  
Acetic Acid ◽  
Ethanol Yield ◽  
Batch Process ◽  
Gas Production ◽  
Reverse Reaction ◽  
Side Reactions ◽  
Aqueous Acetic Acid ◽  
Type Reactor ◽  
Flow Type ◽  
Batch Type

Ru-Sn/TiO2 is an effective catalyst for hydrogenation of aqueous acetic acid to ethanol. In this paper, a similar hydrogenation process was investigated in a flow-type rather than a batch-type reactor. The optimum temperature was 170 °C for the batch-type reactor because of gas production at higher temperatures; however, for the flow-type reactor, the ethanol yield increased with reaction temperature up to 280 °C and then decreased sharply above 300 °C, owing to an increase in the acetic acid recovery rate. The selectivity for ethanol formation was improved over the batch process, and an ethanol yield of 98 mol % was achieved for a 6.7 min reaction (cf. 12 h for batch) (liquid hourly space velocity: 1.23 h−1). Oxidation of ethanol to acetic acid (i.e., the reverse reaction) adversely affected the hydrogenation. On the basis of these results, hydrogenation mechanisms that include competing side reactions are discussed in relation to the reactor type. These results will help the development of more efficient catalytic procedures. This method was also effectively applied to hydrogenation of lactic acid to propane-1,2-diol.

The diffusion of electrolytes in a cation-exchange resin membrane I. Theoretical

1955 ◽  
Vol 232 (1191) ◽  
pp. 498-509 ◽  
Keyword(s):  
Aqueous Solution ◽  
Activity Coefficient ◽  
Cation Exchange ◽  
Exchange Resin ◽  
Volume Fraction ◽  
Cation Exchange Resin ◽  
Physical Nature ◽  
Concentration Difference ◽  
Flow Through ◽  
Resin Membrane

An equation for the flux of electrolyte through a water-swollen cation-exchange resin membrane separating two solutions of the same electrolyte at different concentrations is derived on the basis of several assumptions regarding the physical nature of a swollen resinous exchanger. The complete flux equation contains three terms, one determined by the concentration difference across the membrane, another determined by the variation of the activity coefficient of the electrolyte with concentration in the membrane and a third concerned with the rate of osmotic or hydrostatic flow through the membrane. If ions in the resin are transported entirely in an internal aqueous phase, the mobilities required for the flux equation can be related to mobilities in aqueous solution and to the volume fraction of resin in the swollen membrane. The treatment is readily extended to anion exchangers.

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