Questions tagged [adsorption]
The adhesion of atoms, ions, or molecules from a gas, liquid, or dissolved solid to a surface.
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How to Prepare Vanadium (Na3VO4) solutions buffered at pH = 7.5?
"I need to conduct adsorption studies on Vanadium using various substances like biochars and nanooxides. To prepare Vanadium solutions up to 320 ppm with a pH buffered at 7.5 using PIPES buffer, ...
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DIY method for regenerating activated carbon in air filters
I am interested in regenerating activated carbon used in general house-hold air filters. I am looking for a sufficiently efficient and easy method to do this in home setting. A little tinkering in a ...
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Proper batch adsorption mechanism for heavy metals
I'm a college student with scope on environmental science, specifically the adsorption of heavy metals in aquatic media.
Currently, I suffered from serious issue of batch adsorption mechanism, which ...
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Activated charcoal for water filtration: Granules vs Pellets
NOTE:
After further investigation into the producer I found out that granules are made of 100% coconut shell whereas pellets of 100% hard coal.
This renders this question meaningless.
Apologies for ...
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Is the line between physisorption and chemisorption species specific?
I was studying about heterogenous catalysis, and my Professor said something along the line, "When the adsorption energy is comparable to (or lower than) heat of evaporation, then it is ...
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Is BET equation applicable to only monolayer adsorption range?
One of my senior colleagues is stating that although BET adsorption isotherm equation hypothesises about multilayer adsorption, the P/P0 values (usually from 0.05 to 0.3) accountable for BET surface ...
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Enthalpy of adsorption and adsorption rate
What I want to know is about the adsorption enthalpy change by the change of surface coverage and the adsorption rate. In general situations, adsorption would be exothermic. So in the Gibbs free ...
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How do metal hydrides behave in a non-hydrogen closed system?
I am curious about the fundamentals of metal hydrides and how adsorption/desorption works in non-hydrogen systems. My understanding is that the atom ratio M/Hx of the metal hydride is a function of ...
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What is the chemical mechanism at work during the carboxylation of graphene oxides?
The literature describes carboxylation as an efficient technique to increase the ability of graphene oxide to adsorb metals, as it increases the content of carboxylic acids in the material, while ...
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Do "pseudo Van der Waals" gases exist?
In college, when deriving the Langmuir isotherm for gas-solid adsorption, the professor proposed a modified version of the Van der Waals state equation, what he called the "pseudo Van der Waals ...
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How to minimize sample dispersion during spotting for paper electrophoresis?
I am separating highly polar amino acids and their derivatives using paper electrophoresis. This requires pre-wetting a piece of filter paper with electrophoresis buffer (in this case, carbonate-...
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Why does the coordination of alkaline earths by graphene oxides increase as a function of the increasing ionic radius of the species?
The literature describes that the affinity of graphene oxides towards alkaline earth metals presents a positive correlation with their ionic radius (for example, Klímová et al. (2016) and Sófer et al. ...
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Are carboxylic anhydrides in graphene oxides considered adsorption sites for metals? If so, are they more or less reactive than carboxylic acids?
The literature abundantly addresses the fact that carboxylic acids present in graphene oxides act as efficient adsorption sites for metals in aqueous solutions (e.g., HE et al., 2021; ZHAO et al., ...
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Understanding isosteric enthalpy (heat) of adsorption
I am trying to understand what is isosteric heat of adsorption. Based on van't Hoff equation:
$$ \left(\frac{\partial \ln K}{\partial T}\right)_θ = \frac{ΔH^\circ}{RT^2} $$
and $ΔH^\circ$ is defined ...
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Why do silver halide crystals in suspension, develop a surface charge
This is a question related to analog photography. Photographic films have a suspension of silver halide crystals in them, and these crystals have adsorptive properties which are used in this ...
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How rate of absorption remains same throughout the process?
While reading surface chemistry, I got
Rate of adsorption is high at begining and then decreases till equilibrium is attained . On the other hand , rate of absorption remains same throughout the ...
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Adsorption on solids - homogeneous/heterogeneous surface definition
How could we define homogeneous and heterogeneous surfaces (rigorously)?
It is among my exam questions (but I could not find any definition in my textbook or on the internet).
I would say the ...
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Why is there preferential adsorption of a common ion during preparation of colloids by peptization?
There was a similar question asked here on Chem SE, but the answer was not very satisfactory to me, so I am asking a fresh question.
Peptization is the process of creating a colloid from a precipitate ...
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A physical meaning of the Danckwerts boundary condition in terms of concentration profile (adsorption)
Can someone please explain to me in a simplified way, what exactly does a well-recognized Danckwerts boundary condition do to the concentration profile of adsorption phenomena? I just cannot find a ...
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Units conversion of Henry coefficient in adsorption on solids [closed]
In a database of solid microporous materials I have the Henry coefficient in units of $\pu{mol kg^{-1} Pa^{-1}}.$ How to convert to $\pu{Pa^{-1}}?$
I tried to multiply by the molar mass of the sorbate ...
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Why is the IUPAC definition of adsorption so different from other definitions?
NB: This question has been edited. Originally, some of the confusion was caused by me not knowing that condensed phase could refer to solid phases as well. This has been removed, but the confusion ...
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Is there a practical re-use value gained by grinding up activated carbon that is spent/saturated?
I want to buy bulk activated carbon for use in a DIY air-filtration set-up, like this, to improve air quality in my bedroom.
From what I understand, the relatively larger sizes of carbon media on the ...
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Why does chemisorption decrease with increasing temperatures?
Why is it that chemisorption decreases with higher temperatures?
The explanations I found online were quite vague and one of them cited Le Chatelier's principle, but I thought chemisorption is an ...
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Porous materials: Is the expression of a mean free path $\overline{\ell}$ of the gas molecule valid for a binary mixtures?
Suppose that I have a binary gas mixture at low pressure. Can I calculate the mean free path $\overline{\ell}$ of the gas molecule in a pores of solid material by substituting a molecular weight of a ...
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Dynamic viscosity of gas mixture (appropriate estimation)
What estimation of the dynamic viscosity $\eta = f(T)$ $([\eta] = \pu{Pa·s})$ of the gas mixture components would you recommend during adsorption at a low temperature, approx. $\pu{293 K}$ to $\pu{333 ...
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Finding the Freundlich adsorption isotherm from the graph of log(x/m) v/s log(p)
The following problem was asked in JEE Mains 2020 (Sept 2, Shift 1),
The mass of gas adsorbed, $x$, per unit mass of adsorbate, $m$, was measured at various pressures, $p$. A graph between $\log\frac ...
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Adsorption of Cu2+ using banana peels for pH 2,2.5,3,3.5,4
so basically I did my experiment which is the title. This is my procedure and results:
Make 0.05M CuSO4
pipette 50ml CuSO4
change to respective pH values using HCl
Add 2g of oven-dried banana peels
...
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How is the hydration state of a chemical related to its adsorption of water?
I am trying to understand adsorption and hydration states better, and I was thinking about the different hydration states of calcium sulfate - anhydrous ($\ce{CaSO4}$), hemihydrate ($\ce{CaSO4*1/2H2O}$...
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Column Dispersive Mass Balance analytical / numerical solution
Is there any analytical solution for the most common expression of column mass balance:
$\dfrac{\partial C}{\partial t} + \left(\dfrac{1+\varepsilon}{\varepsilon}\right)\dfrac{\partial q} {\partial t} ...
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Energy and impurities balance for adsorption with a fixed bed (with description)?
Do you have any suggestion where to look for a source of information about energy and impurities (component) balance for adsorption of mixture CO2/H2O in fixed bed?
I have looked into many articles /...
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