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, ...
1 vote
28 views

### 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 ...
151 views

### 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 ...
24 views

### 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 ...
264 views

### 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 ...
104 views

### 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 ...
88 views

### 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 ...
1 vote
90 views

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 ...
1 vote
33 views

### 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 ...
28k views

### Why is Charcoal such an excellent adsorbent?

Charcoal (also activated charcoal) is known to adsorb a huge variety of substances including a variety of paints, dyes and many different kinds of ions. Moreover, the amount of adsorption at normal ...
1 vote
24 views

### 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 ...
82 views

### 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 ...
4k views

### Why Freundlich adsorption isotherms fails at high pressure conditions?

Experimentally it was determined that extent of gas adsorption varies directly with pressure, and then it directly varies with pressure raised to the power 1/n until saturation pressure Ps is reached. ...
1 vote
15 views

### 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-...
37 views

### 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. ...
1 vote
446 views

### Is activated charcoal an air purifier?

It's well known that activated charcoal is an adsorbent and due to very big surface area per unit of mass it can adsorb a lot of particles. Let's take as an example for my question this product on ...
287 views

78 views

### hydrodynamic thickness of polymer vs. concentration of electrolyte?

I've measured the hydrodynamic thickness of a NaPSS layer on polystyrene latex and plotted it against the concentration of the supporting electrolyte, NaCl. My graph shows a general decrease in ...
4k views

My textbook reads as follows: When a gas is adsorbed, the freedom of movement of its molecules become restricted. This amounts to decrease in the entropy of the gas after adsorption, i.e. Entropy ...
1k views

### Order of reaction in adsorption process

(1) $\ce{PH3(g) <=>[W]PH3(adsorption)->[W]P(s) + 3/2 H2(g)}$ The decomposition of phosphine on tungsten surface at low pressure is a pseudo first order reaction. This is because the rate of ...
1 vote
525 views

### Is there a direct relationship between the adsorption energy and the catalytic activty

I have seen in several papers, where people correlate adsorption energy with the catalytic activity; the greater the adsorption energy, the greater would be the catalytic activity. I understand that ...
Brunauer–Emmett–Teller (BET) surface area is measured by specific surface area of the adsorbent. BET surface area is measured by using non-corrosive gases like $\ce{N2}$, $\ce{CO2}$, $\ce{Ar}$ etc. ...