Sorption - Science topic

To convert weight percentage to milliliters per minute (ml/min), you need additional information such as the density of the substance, the flow rate in terms of weight (e.g., grams per minute), and the total mixture flow. Here’s a general approach:

1. Obtain the weight percentage: This is typically the weight of the solute divided by the total weight of the solution, multiplied by 100.

2. Convert weight to volume: To go from weight (grams) to volume (milliliters), you’ll need the density of the substance, using the formula:

Volume (ml) = Weight (g)/Density (g/ml)

3. Determine the flow rate: If the flow rate is given in terms of weight (e.g., grams per minute), you can then convert it to ml/min by dividing by the density of the substance:

Flow rate (ml/min) = Flow rate (g/min)/Density (g/ml)

This research proposal aims to optimize the sorption of dyes from wastewater using natural and synthetic textile fibers through Response Surface Methodology (RSM), evaluating the effects of parameters like pH and dye concentration. The study seeks to identify optimal conditions for maximum dye removal efficiency, contributing to sustainable wastewater treatment and resource recycling in the textile industry.

Yes, it is possible to improve the sorption of rare earth metals through complexation with carboxylic acids. Carboxylic acids can form complexes with rare earth metals due to the presence of their carboxylate groups (-COO-), which can act as ligands. These complexes can enhance the affinity of the rare earth metals for sorption onto various materials, such as ion exchange resins, activated carbon, or other solid sorbents. The complexation can increase the stability of the metal ions in solution, making them more accessible for sorption processes.

While the colour change in the metal solution after adsorption can provide qualitative insights into the efficacy of metal removal by the sorbent, quantitative analyses are necessary to accurately assess sorption capacity. By combining qualitative observations with quantitative measurements, you can better understand the relationship between sorbent dose, colour change, and metal sorption capacity in adsorption tests for heavy metal removal.

Amelia Suet May Tan, to compare adsorbed concentrations of 4 sorbates by 4 sorbents and determine the most sorbed and fastest sorbed sorbate-sorbent combination, you can use a two-way ANOVA with post hoc tests. This will assess the main effects of sorbate and sorbent, as well as their interaction. Normality tests may not be needed if ANOVA assumptions are met. If normality is violated, consider non-parametric tests. Additionally, analyze time data with appropriate methods (e.g., survival analysis) to determine the fastest sorbed combination. With tools like OriginPro, you can then visualize your data the way i quickly did for you. For more relavant discussion you can ask me on my WA; https://wa.me/+923440907874. Good luck!

Hello, Vincent,

1. Yes, you can use a buffer, but one should consider the potential interferences of buffer ions. For example, buffer anions could form complexes with metal cations of interest both in solution and in an adsorbed phase thus affecting the metal adsorption affinity. On the other hand, if the intention is to maintain a constant pH, how may a pH adjustment per se affect a surface? I might think that the adjustment changes the composition of a background ionic composition, and to avoid that, a background electrolyte is useful.

2. Regarding varying solution concentration vs solid to solution ratio, I vote for the first one, and always avoid varying sorbent to solution ratio. There are several reasons for that: 1) a so-called dosage effect when changes in sorbent to solution ratio affect an equilibrium adsorption isotherm determined at a given dosage for different solute concentrations. If this effect is present, by any reason, then, varying sorbent to solution ratio for a given initial solute concentration produces the solution/sorbed concentration pairs belonging to apparently different isotherms; 2) in some cases, specifically, in the work with environmental and geological materials (e.g., soils, sediments, coal, rocks), sorbents may release soluble material capable of complexing with solutes in solutions (e.g., metals). The concentration of released soluble material will vary when a sorbent to solution ratio varies; 3) a kinetic of attainment of equilibrium may change depending on a sorbent to solution ratio, which needs to be reexamined for each such a ratio; 4) in some cases, varying solute concentrations for a given sorbent to solution ratio allows reaching a broader range of equilibrium solution concentrations that when maintaining a given initial dissolved concentration and varying a sorbent to solution ratio.

When looking at the Total Density of States function of two reactants and a product, bonding can be inferred from the Overlap Population-based Density Of States (OPDOS) between two molecular orbitals 2. The OPDOS between two molecular orbitals has large positive values at energies where the interaction is bonding and negative values where the interaction is anti-bonding 2.

Therefore, if there are significant positive values in the OPDOS between two molecular orbitals at specific energies, it can be inferred that bonding has occurred between those orbitals.

see:

Dos: Density of States — ADF 2023.1 documentation (scm.com)

In your study, you used a NaNO3 (sodium nitrate) solution to investigate nitrate sorption using a sorbent. The reviewer is asking about the effect of the sodium ions (Na+) in the sorption environment and mentions a "double effect."

Here's what the effect of Na+ could be and how it might relate to the concept of the "double effect":

In summary, the presence of sodium ions from the NaNO3 solution can influence the sorption process in various ways, including through changes in ionic strength, the salting-out effect, and background interactions. These effects can impact the availability and behavior of nitrate ions during sorption onto the sorbent. It's important to consider these aspects when interpreting your experimental results and discussing the role of sodium ions in the sorption system.

You can discuss whatever, but we are supposed to follow IUPAC recommendation regardless you like it or not. See

and refs in it.

Take a look here

Thank you for the insight

Louis Nguyen To obtain Non-equilibrium (NE)-SAFT from an existing equilibrium SAFT code, various changes must be made to the code.

To begin, you would need to adjust the equations used in the SAFT model to account for the polymer volume (or polymer density) dependency on temperature and pressure. This would very certainly necessitate some adjustments to the mathematical form of the equations.

Second, you'd need to change the code's input such that temperature and volume-dependent variables may be provided as independent variables rather than temperature and pressure. This would very certainly necessitate changes to the input procedures and input storage.

Finally, the output routines would need to be modified to allow for the computation of thermodynamic parameters important to the NE-SAFT model, such as the equation of state, heat capacity, and internal energy.

It may be feasible to discover a faster workaround, but it is probable that making these changes to the current code would be easier and easier than trying to find a workaround. Changing the code directly ensures that the result is compatible with the NE-SAFT model.

It's also worth noting that these revisions will very certainly necessitate a solid grasp of the mathematical underpinnings of the SAFT model, as well as the alterations required to achieve the NE-SAFT model.

In the two-step process, biomass is carbonized at the first stage, for a higher carbon yield. At the second stage, Activation to higher pore volumes and surface areas.

Absorption is when a substance in one state is incorporated into another of a different state, such as a liquid absorbed by a solid. Adsorption is when a substance adheres to the surface of another phase. The reverse of absorption is desorption. Desorption is when a substance detaches from or through a surface.

M A C K Hansima

SEM studies are done to look at the particle size of the powder that is used for adsorption. The smaller the particle size of the clay, the greater will be the adsorption. It is not clear from your question what you are going to use SEM for.

Figured it out! Selected the wrong model but got it to work. Graphpad has a predesignated "Langmuir" model but there's the specific vs total binding models that require some finangling to get it to work. The graphs look very sharp.

Good day! It is hard to say which kind of nanoparticles you are describing. Probably, if you face higher efficiency, you should suppose some changes in its properties, while it is hard to say are this changes sensible or no.

You can check this study for help

Hi,Like you, I absorbed gas on graphene and used Oplsaa force field

but first time i uesd isotherm ff but didnt work so i changed it

As far as I know, it is impossible

Regards,

K

Also kindly see the following useful link: https://www.sciencedirect.com/topics/earth-and-planetary-sciences/adsorption

I agree with Mohamed Khedawy.

Thank you very much Zenon Hamkalo for your insight and for attaching the very useful article. Yes, You are right the role of aggregates in the stabilization of soil organic matter has been insufficiently studied in comparison with organo-mineral interactions. Therefore there is need to further study the aggregation model more.

Many thanks and best regards

When testing new sorbent material, you can use for kinetic modelling : the pseudo second order and intraparticle diffusion. For equilibrium modeling use freundlich, Dubinin raduskevich and sips. For both calculation use the non linear equation for the model.

Raheem Bahadar You answered your own question. Use BJH (or DFT) pore size calculations from gas sorption isotherms (usually N2 at 77K) for these materials. Gas sorption covers the entire mesopore range (2-50nm according to IUPAC classification). In fact, the method can go as large as 400-500nm. But if you have pores larger than that (well into the macropore range) you should consider mercury intrusion porosimetry.

Hi, Michal,

as far as I can understand, you pass water containing metabolites through the two adsorbents, and after year and half something stops to work. The remaining concentrations of metabolites in the effluent rise as compared with the initial work period. If so, one possible explanation is that there is an equilibration of adsorbents with metabolites present in solutions. In a beginning, almost all metabolites are adsorbed, but when continuing flushing the solution through the adsorbent columns, finally the adsorption sites become saturated by adsorbates till the extent which is in equilibrium with the initial compounds concentrations in solution. The ability of adsorbents to remove compounds from solution disappears. Perhaps, simple tests and calculations help to check this explanation. The adsorption isotherms measured at least in the batch conditions are needed, and, the knowledge on how much of the solution was transferred through the columns. From the second, one may estimate the amount of compounds retained by adsorbents after all the period of their use. From the first experiment, one may learn what is the solution concentration to be in equilibrium with the retained adsorbates.

However, all that is in assumption that there was no (bio)degradation. Almost certainly there is degradation of adsorbates, and well as changes in adsorbent porosity and its particle packing. The columns become aged and loosing their efficacy...perhaps so....and, by the way, as recommended above, it is indeed important to control pH during all the history; some organic compounds may change drastically their ability to adsorb depending on pH, and pH may indeed change during the time of adsorbent material use

Thanks you for your suggestions. I know these journals.... I am looking for SPECIFIC references by title author.

Il fallait mieu refaire analyse pour montrer bien hysterisis

Walter Ojok interesting question and even i would love to see the right answer

Je pense oui

Dear Pouyan Golestaneh, the NELF model treats both solubility and permeability isothermes, may be its best advantage is found when studying glassy polymers. Please check these documents. My Regards

Thank you Bojidarka B. Ivanova for the constructive suggestions.

!♥Following

Mirosław Grzesik Some top researchers accept these results and relations between the models when something not click in your mind it does meant it is worthless.

If you mean non linear regression, you may use Maltab, polymath and other relevant softwares

Pseudo first order kinetic model.

kindly suggest alternate material for separation of liquid solid for nutrient adsorption study

Abdallah Bouguettoucha, I'm sorry but it seems you are confusing two terms: order of reaction and molecularity of reaction. The number of colliding molecules may influence the order of the reaction, but it does not have to, and very often it does not. Moreover, the order of the reaction applies mainly to homogeneous reactions for which the kinetic equation (rate law) has the form of a power monomial. Heterogeneous reactions are generally of no order except for those whose kinetic equation is a power monomial. Molecularity is not considered in the kinetic equations for homogeneous reactions. It can be included in the kinetic equations of heterogeneous reactions (the exponent in the denominator of the L-H equation).

Dear Yury Gorbanev, these type of catalysts are much more used in thé Tropsch-Fischer process. Many conventional characterization techniques are used to titrate reactive sites. Please check the following links. My Regards

Yes, you can --I think -- if you are interested in the sum.

Otherwise, use a polynomial (metamodel) per dependent variable.

Also see either constrained RSM or multi-objective Pareto RSM; see my 2015 book or website.

http://downloads.hindawi.com/journals/jchem/2017/3039817.pdf

Nice Dear Mikhail Borisover

Dear Jakub,

first of all you should understand the differences between the BET model and the BJH method.

The BET surface area represents the probe accessible surface area as it is based on a calculation of an area coverd by the volume of gas within the monolayer. It is (except for microporous materials) a physically meaningful value and thus the BET-methode is the IUPAC recommended method for the determination of the specific surface area.

In contrast, the BJH model assumes the formation of an adsorbate layer based on a statistical thickness function (e.g. deBoer or Hasely) and condensation of gas at higher pressure as described by the Kelvin equation. Knowing the Kelvin radius and the thickness of the adsorbed layer will allow to calculate the pore size (with often times large errors) and based on this the pore volume. The pore volume can then be used to calculate the pore size as follows:

A = 2 V/ r

where A is the surface area, V is the pore volume and r is the radius of the pore.

This shows that the surface area calcualted in this way is a geometric surface area base don many assumption: Cylindircal pores, a theoretical statistical thickness of the adsorbate and capillary condensation based on the Kelvin equation. Therefore, the values obtained in this way have no physical meaning.

Additionally, looking at your measurement, the data quality is very poor, which has serveral reasons. You are using a fixed P0 value (and a low one I might add) which is not a good idea (but I think you are limited by the instrument?). Also the equilibration parameters are not ideal, I would use equlibraition times of at least 3 minutes rather than the 1 minute you chose. The adsorbed amount is not increasing monotonically which is either cause by the parameters you chose or structural changes within the material.

I checked the data and think that you have also selected an inappropriate range of point for the BET analysis. Selection of point between 0.05 and 0.3 yields a surface area of roughly 50m2/g while the BJH method give about 35 m2/g. Note that the value calculate with the BJH method is not an actual probe accessible surface area!

I hope this helps,

Markus

Please look at the following below attahed papers which may help you in your analysis:

Thanks

S.s. Metwally thank you so much..sure I will

Are you asking about distinguishing between degradation and sorption OR trying to explain known differences between biochar treatments in degradation rate?

Don't forget that biochars are alkaline and contain minerals, depending on the feedstock beneficial and/or toxic. Did you measure the relevant changes caused by the treatments, e.g. pH, EC, nutrients, respiration rate?

Adil Mihoub the process is costly and time consuming as well and after neutralizing is it effectly improve the physiochemical characteristics of soil?

You need at least 3 temperatures to get reliable isosteric heat of adsorption data. So you need one temperature in between 0 and 25 say 15 degrees or higher than 25 say 35 degrees to get the true isosteric heat.

It is not that wise to to combine all these applications into one whole system. Flexibility brings the opportunity, together with challenge and limitation. Think about that the solar heat could fully realize one technology but it cannot be used for the similar amount output by using other applications at the same time. Also the demands should be considered at the very beginning. If no heat and cooling demand, electricity could be a solution.

DFT (NLDFT and QSDFT) methods are much more suitable than BJH for micro and mesopores.

For BJH you need the desorption branch (have a look at the original paper, I think I uploaded it in RG somewhere...).

You cannot measures macropores by adsorption (macropores behave like non-porous surface towards gas molecules)... you need something like mercury porosimetry.

Charges in soils are as a result of permanent charges from the clay minerals which are unique to the type of minerals and variable charges (also referred to as pH dependant charges) provided by the type, age and quality of organic matter. Thus, changing pH levels will affect variable charges (provided by the organic matter), with increasing pH levels will increase variable charges. However, changes in pH should have little or no effect on charges provided by the clay minerals.

Thank you guys

@Hafiz Muhammad Zia Ur Rehman can you please elaborate.

The mass of soil, area of 1 ha (= 10,000 m²), depth 0.3 m (= 300 cm):

V (volume of soil) = 10,000 m² * 0.3 m = 3,000 m³

bulk density 1.4 g.cm^-3 is equal to 1,400 kg.m^-3

m (mass of soil) = 3,000 m³ * 1,400 kg.m^-3 = 4.2*10⁶ kg

Sorption capacity of soil for P: 667 mg.kg^-1

the total mass of sorbed P is 4.2*10⁶ kg * 667 mg.kg^-1 = 2.801.10⁹ mg = 2.801.10³ kg of P.

Regards

Vit

Hi, Raffaella,

there are multiple methods, and each one has its own problem. We are using very often sodium azide at the 200 mg/L level. This is very classic approach, its advantage is that (most probably) it has small effects on soil properties (not always) but it is not necessary effective. HgCl2....in your case it may be problematic since you have competing metals but perhaps concentrations are not comparable. HgCl2 is considered as biocide less affecting soil.

From my experience, in the past, seeing a strong biodegradation of phenol in peat solutions, we succeeded to deal with that by using simultaneously sodium azide, sterilizing glassware and performing sorption in the nitrogen atmosphere. But typically, I prefer gamma-irradiation of soils which is very effective. But....it may have effects on soil sorptive properties, in particular due to possible release of DOM. Yet, I would consider irradiation as a primary solution. If you do not work with organic amendments, soil per se might release limted DOM concentrations, if at all. For your possible interest, I have attached our paper (in that, you may find some discussions of the literature regarding use of irradiation).

First you have to deal with a fundamental difficulty. Starch is a mixture of two biopolymers, linear amylose (MW ca 10E6) and branched amylopectin (MW ca 10E8). So starch has a bimodal molar mass distribution which is very broad. Because for most starches, amylopectin is the dominant fraction (typically 70-80 %) and because the preferred experimental method is size exclusion chromatography with light scattering detection, which is more sensitive to the high molar mass species, the molar mass of amylopectin is a rather good approximation for that of whole starch, except for the amylose-rich starches.

In doing molar mass determinations one has to ensure that the starch has been molecularly dissolved in a way that no molecular degradation has occurred. This is not a simple task. Fortunately, suitable methods have been developed and literature values for most common starches are available. The authors of the paper provided by Md. Abdur Rahman are real experts in the field but their paper does not provide numerical values. Data for various starches were presented in a paper by Yoo and Jane (Carbohydr. Polym. 49 (2002) 307-314) which you find in the attachment.

Flory-Huggins theory is the opt method

Thanks for your clarification.Release of some chemicals from the AC in time of the sorption experiment could well be a reason for enhancing the EC; but, on the other hand, the EC attains higher values when lower conc of Cu(II)SO4 is used. So, if the previous assumption is true, it means that the release of that EC enhancing chemical is more for the lower conc of Cu(II)SO4. Has the maximum EC been found for 0.00001 moldm-3? or it was higher for 0.001 moldm-3? If it has been found that the EC was maximum for Cu(II)SO4 conc of 0.001 mol/dm3 rather than for 0.00001 mol/dm3, then probably the sorption of Cu(II)SO4 on your AC is not favoured at lower concentrations of Cu(II)SO4 (conc~0.00001 moldm-3); because for a very lower conc of adsorbate, the mass flux to the adsorbate at adsorbate/solution interface becomes insignifcant and adsorption of the adsobate on the adsorbent becomes very difficult. These could enable the free existence of those ions in the solution to further increase the EC.

Gareth, PFASs impacts to concrete are more of a concern as a result of the concrete remaining as a long lasting source of PFASs to the environment via long term leaching. We are working on some treatment solutions to prevent this. Cheers, Ian

Thank you for all your answers and advise

As biomass undergoes thermolysis, its original polymeric molecules are broken up and transformed giving rise to three products: syngas (CO, H2, CH4), bio-oil (acetic acid, phenolic-like compounds, alcohols, H2O etc) and biochar+minerals. As temperature increases the biochar is more dominated by polyaromatic compounds. We can illustrate this transformation from original biomass comprising of hemicellulose, cellulose and lignin to biochar using the H/C and O/C ratio in a van Krevelen diagram (http://www.publish.csiro.au/?paper=SR10010; ). H/C and O/C ratios are used in the biochar community to estimate the stability of biochar in soil, which is important for calculating the carbon sequestration potential. In your case it may be of importance in determining the number of regeneration cycles. Not sure whether anyone looked at this. In addition, and as mentioned by Amita Shakya already, the O/C ratio can inform us about the general polarity of the material. To know the type and quantity of functional groups present you could try Boehm titration ( ; https://linkinghub.elsevier.com/retrieve/pii/S0008622313008981; http://linkinghub.elsevier.com/retrieve/pii/S0016706111001091). Be sure that your biochar has been washed to avoid interference.

As O/C decreases with increasing temperature, the adsorption mechanism shifts from mainly ion exchange based to physisorption (van der Waals, London dipole). The sorption capacity should drop due to the weaker nature of physisorption, but typically the BET surface area increases exponentially (with increasing temperature) thus compensating for it. Something else you may wish to consider in certain adsorption systems is the presence of natural organic matter which competes with the heavy metals for the surface. An example can be found here ( ).

As for the yield, since both H/C and biochar yield are correlated to temperature, these two (H/C vs biochar yield) should be too.

You could carry out a meta-analysis and develop a correlation between O/C ratio and heavy metal adsorption capacity. Since type of functional group, pH and BET surface area plays and important role too it may not be that straightforward. It may be advisable to contact an expert in statistics (e.g. Abbas F. M. Alkarkhi).

Hope this helps?

that is a good question Afsane Farhadi Toopkanloo

It might be worth checking the pH during your experiments, just to be sure that it does not change too much during the reaction, as Ca adsorptin varies with pH (H+ ions compete with Ca2+ ions for the same binding sites).

Good luck

Peter Shellus

PAH sorption is one of the processes that govern the soil mobility of individual of individual PAHs. Numerous studies of the correlation of the partition coefficient with soil properties have found that the organic carbon...... Consult the following sources for details ; https://www.sciencedirect.com ;; https://www.ncbi.nlm.nih.gov ; https://www.pubs.acs.org

Yurii,

It is generally difficult to undermine the scientific value of the results of a given experiment. I was convinced of this for a long time, until I started reading works on batch adsorption in a liquid-solid system. Recently, I wrote comments to over a dozen works in this field. In a few of them, it seems to me that the material tested was unstable. Hence, various "surprising" behaviors. And then, in my opinion, both the results of such experiments and their description are of little value. In the case of reliable results, the description by equations may be, but not necessarily. However, as far as the description of data on kinetics and equilibrium of batch adsorption is concerned, I am slowly becoming convinced that it is unnecessary littering of usually valuable works. Mirosław

Langmuir gives you excess sorption, so the benefit of sorption over non-sorption. CBM reservoir engineers use the density of the sorbed phase to estimate absolute sorption and this again to calculate the desorbable gas from coal. The sorbed phase density is typically used as a constant but it is known to depend on P, T and coal type, maybe maturity. So also this is just an estimation and does not reflect reservoir conditions. I guess this unknown will be part of any uncertainty analysis when developing a coalbed reservoir

Also, you can use t-plot method

Hi, Antonio,

was N2 sorption measured classically at low temperature? Two (hypothetical) reasons: (1) octane-based SSA, even determined from an apparent (?) BET behavior, (was it?) involved in fact formation of multiple layers ..I would check with a great attention how well the BET-like trend looks like BET...Was it indeed BET or measuring distribution coefficients at few concentrations?

(2) In some cases nitrogen-based SSA is known to be less than the CO2-based SSA, due to the differences in temperature and strongly retarded diffusion of N2 at low temperature in small pores, as compared with CO2. Octane is obviously large nolecule (but not when it becomes a chain, at least in one direction), yet, here there might be also a similar effect involving an effective penetration of octane into relatively small pores at 30 C, ad compared with retarded diffusion of N2 at lowe temperatures. How porose is the material and how hysteretic is gas sorption? This could give an idea about role of small pores in accomodation of different size gases measured at different temperatures...

Please see the short instruction film about SPE recorded by Agilent Technologies:

Best regards,

Mateusz

Everything will depend on the slope but at 15 minutes it will be difficult to have correct data

me at 30 minutes I can extract the data but provided that the slope is not abrupt

You must remember, however, that on the one hand are my views and on the other the views of reviewers. And judging by the number of works, where there is a "cause and effect" relation between the compatibility of simple functions with kinetic data and the mechanism of adsorption, their view prevail. Regards,

what is understood under "non-equilibrium sorption" as contrasted with "sorption kinetics"? "Non-equilibrium" presumes either sorption or desorption kinetics. or, is that about exit from a metastable state?