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Questions and Answers
What is the increase in the concentration of surfactant molecules, ions, etc., on the surfaces of minerals or on the interfaces such as air-water called?
What is the increase in the concentration of surfactant molecules, ions, etc., on the surfaces of minerals or on the interfaces such as air-water called?
Adsorption
What is the material that does the adsorption process called?
What is the material that does the adsorption process called?
Adsorbent
What is the substance which is adsorbed on the adsorbent called?
What is the substance which is adsorbed on the adsorbent called?
Adsorbate
What are solid substances that adsorb dissolved substances (solutes) from solutions called?
What are solid substances that adsorb dissolved substances (solutes) from solutions called?
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What are the two types of adsorption that can occur at the solid/liquid interface?
What are the two types of adsorption that can occur at the solid/liquid interface?
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What do we call the adsorption that occurs through adsorption of counter ions in electrical double layer?
What do we call the adsorption that occurs through adsorption of counter ions in electrical double layer?
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What do we call the adsorption that occurs when a chemical reaction between species in solution and ions constituting mineral surface?
What do we call the adsorption that occurs when a chemical reaction between species in solution and ions constituting mineral surface?
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In physical adsorption, the forces of attraction holding the adsorbate are Vander Waal's forces.
In physical adsorption, the forces of attraction holding the adsorbate are Vander Waal's forces.
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In chemical adsorption, the forces of attraction holding the adsorbate are chemical bond forces.
In chemical adsorption, the forces of attraction holding the adsorbate are chemical bond forces.
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In physical adsorption, bonding between molecules and the surface is by weak van der Waals forces.
In physical adsorption, bonding between molecules and the surface is by weak van der Waals forces.
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In chemical adsorption, a chemical bond is formed between molecules and the surface.
In chemical adsorption, a chemical bond is formed between molecules and the surface.
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In physical adsorption, adsorption occurs at high temperatures.
In physical adsorption, adsorption occurs at high temperatures.
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In chemical adsorption, adsorption occurs at low temperatures.
In chemical adsorption, adsorption occurs at low temperatures.
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Physical adsorption is an irreversible reaction
Physical adsorption is an irreversible reaction
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Chemical adsorption is a reversible reaction
Chemical adsorption is a reversible reaction
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Physical adsorption can result in more than one layer of adsorbate on the adsorbent surface.
Physical adsorption can result in more than one layer of adsorbate on the adsorbent surface.
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The adsorption heat in physical adsorption is 3-4 kcal/mol.
The adsorption heat in physical adsorption is 3-4 kcal/mol.
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The adsorption heat in chemical adsorption is 10-1000 kcal/mol.
The adsorption heat in chemical adsorption is 10-1000 kcal/mol.
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The binding in physical adsorption can be considered as very weak.
The binding in physical adsorption can be considered as very weak.
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The binding in chemical adsorption can be considered as very strong.
The binding in chemical adsorption can be considered as very strong.
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In physical adsorption, no electron sharing occurs between the adsorbent and adsorbed molecules.
In physical adsorption, no electron sharing occurs between the adsorbent and adsorbed molecules.
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In chemical adsorption, the sharing of electrons occurs between adsorbent and adsorbed molecules.
In chemical adsorption, the sharing of electrons occurs between adsorbent and adsorbed molecules.
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What are the factors that affect adsorption from solution at the S/L (Solid-Liquid) interface?
What are the factors that affect adsorption from solution at the S/L (Solid-Liquid) interface?
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What type of adsorbent is most important for controlling environmental pollution?
What type of adsorbent is most important for controlling environmental pollution?
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What is the process of adsorption usually studied through?
What is the process of adsorption usually studied through?
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What is the graph between the amounts of adsorbate (x) adsorbed on the surface of the adsorbent (m) and the concentration at a constant temperature known as?
What is the graph between the amounts of adsorbate (x) adsorbed on the surface of the adsorbent (m) and the concentration at a constant temperature known as?
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What are the different types of Adsorption isotherms?
What are the different types of Adsorption isotherms?
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What does the BET method relate to?
What does the BET method relate to?
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The BET method is based on the adsorption of gas on a surface.
The BET method is based on the adsorption of gas on a surface.
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The amount of gas adsorbed is independent of the surface area.
The amount of gas adsorbed is independent of the surface area.
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The BET method is a cheap, fast, and reliable method for measuring surface area.
The BET method is a cheap, fast, and reliable method for measuring surface area.
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The BET method is not applicable in many fields.
The BET method is not applicable in many fields.
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What is the adsorption density formula used to calculate?
What is the adsorption density formula used to calculate?
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What is the most important aspect of the adsorption experiment?
What is the most important aspect of the adsorption experiment?
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What type of equipment is used to determine the equilibrium concentrations of chemicals?
What type of equipment is used to determine the equilibrium concentrations of chemicals?
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What is the process called when surfactant molecules form aggregates on the surface?
What is the process called when surfactant molecules form aggregates on the surface?
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What is the process called when surfactant molecules form aggregates in solution?
What is the process called when surfactant molecules form aggregates in solution?
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What is the point at which surfactant molecules begin to form micelles called?
What is the point at which surfactant molecules begin to form micelles called?
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What does the plateau region in an adsorption isotherm indicate?
What does the plateau region in an adsorption isotherm indicate?
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The surface coating degree of a substance is calculated using the ratio of cross-sectional area of adsorbent to coating area.
The surface coating degree of a substance is calculated using the ratio of cross-sectional area of adsorbent to coating area.
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What is the name of the cationic surfactant used in the modification process of sepiolite?
What is the name of the cationic surfactant used in the modification process of sepiolite?
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Study Notes
Surface and Colloid Chemistry
- The field of study is surface and colloid chemistry, specifically properties of solid-liquid interfaces and adsorption.
- The date is December 2024.
- The professor is Dr. Orhan Ozdemir.
- Adsorption is the increase in concentration of surfactant molecules, ions, etc. on mineral surfaces or interfaces like air-water.
Adsorption
- Adsorbates are substances adsorbed onto a surface.
- Adsorbents are the materials that perform the adsorption process, such as activated carbon.
- Adsorbate is the substance attached to the adsorbent, like metal ions in water.
- Adsorption is the accumulation of ions or molecules on surfaces and interfaces.
- Gas adsorption occurs on solid surfaces, like activated charcoal.
- Surfactant adsorption happens at liquid/air and mineral surfaces.
- Solid substances (adsorbents) adsorb dissolved substances (solutes) from solutions. There are different pore sizes (micropores <2 nm, mesopores 2-50 nm, macropores >50 nm).
Adsorption at Solid/Liquid Interfaces
- Adsorption of ions from solution at mineral/water interfaces depends on the mineral surface's chemical composition, crystal structure, and charge distribution in the electrical double layer.
- Chemical adsorption occurs if a chemical reaction happens between species in solution and ions in the mineral surface.
- Physical adsorption happens through adsorption of counter ions in the electrical double layer.
Physical vs. Chemical Adsorption
- Physical adsorption uses van der Waals forces.
- Chemical adsorption involves chemical bond forces.
- Physical adsorption typically has a lower adsorption heat range (3-4 kcal/mol).
- Chemical adsorption has a higher adsorption heat range (10-1000 kcal/mol).
- Physical adsorption is usually reversible.
- Chemical adsorption is usually irreversible.
- Physical adsorption can have multiple layers.
- Chemical adsorption usually forms a monolayer.
- Physical adsorption occurs at lower temperatures.
- Chemical adsorption occurs at higher temperatures.
Factors Affecting Adsorption
- Solute concentration
- Temperature
- Surface area of the adsorbent
- pH of the solution
- Pressure
- Time
Applications of Adsorption
- Activated charcoal and silica/alumina gels are widely used adsorbents to control environmental pollution.
- Adsorption is used in various industrial processes.
Adsorption Isotherm
- The process of adsorption is usually studied via graphs known as adsorption isotherms.
- An adsorption isotherm is a graph showing the relationship between the amount of adsorbate adsorbed on the surface of an adsorbent (m) and its concentration (x) at a constant temperature.
- Different adsorption isotherms exist (Freundlich, Langmuir, and BET).
Quartz-Amine Adsorption
- Shows adsorption density in relation to DAH concentration at different regions.
Adsorption Experiments
- Adsorption tests use containers like glass vials.
- Clay mineral in deionized/distilled water is commonly used.
- Chemicals are added to the suspension at various concentrations.
- The mixtures are mixed using an orbital shaker.
- The suspension is filtered (using centrifugation).
Adsorption Experiments Formulas
- A formula (Γ = (Ci - Cf)V/ mS) is given to calculate adsorption density, where:
- Γ is the adsorption density (mol/cm² or mol/g).
- Ci and Cf are the initial and final concentrations (mol/L respectively).
- V is volume (L).
- m is the adsorbent amount (g).
- S is the surface area of the adsorbent (m²/g) (BET).
Preparation of Clay/Chemical Suspension
- Specific concentrations of clay, chemical, and solution volume are used.
- A mixing time of 240 minutes is used.
- Equipment like electronic scales, beakers, and orbital mixers are specified.
Transfer Suspension to Vacuum Pump Filtration System
- The suspension is transferred to a vacuum filtration system to separate solids and liquids.
- A visible spectrophotometer determines the solution's final concentration.
UV/Vis Chemical Analysis
- UV/Vis spectrophotometry measures absorbance to determine the final solution concentration.
- UV/Vis analysis operates by transmitting light to find the amount absorbed.
Different Regions & Values of UV-Vis Analysis
- UV-Vis analysis looks at light between 190 and 400 nm (UV) and 400-700nm (Visible)
- Absorbance values at different concentrations across the UV and Visible spectrum are used to produce a calibration curve.
- A relationship between concentration is created
Calculations of Adsorption Density
- The formula Γ = (Ci-Cf).V/m.S is applied to find the adsorption density, with provided examples.
Measurement of Surface Area (BET)
- BET method determines the specific surface area of a sample using gas adsorption.
- The method is based on gas adsorption at a particular pressure and relates to total surface area.
Sepiolite-HTAB adsorption
- Adsorption takes place on the sepiolite structure and between its components.
- Different regions of the isotherm (I, II, III) have different reasons for adsorption.
Coating Degree Calculations
- Calculations for the coating area and degree are performed based on given equations (examples provided).
- Adsorption isotherms are determined, verified, and quantified.
Adsorption of HTAB on Sepiolite
- HTAB molecules with positive charges adsorb onto the negative charged sepiolite surface, causing the surface to be covered by these electrical forces.
Adsorption of HTAB on Zeolite
-Similar to Adsorption of HTAB on Sepiolite, calculations for the coating degree on the surface of zeolite are performed.
Fundamental Aspects of Bubble-Particle Attachment Mechanism in Flotation Separation
- Various graphs/plots depict the relationship between flotation recovery, attachment time, zeta potential, liquid drainage, and receding contact angle to DAH concentration.
- Plots/graphs are provided.
UV/Visible Adsorption Experiment
- An experiment is described where hexadecyl trimethyl ammonium bromide (HTAB) adsorption onto sepiolite is studied
- Various experiments/methods were used, and the results are tabulated. Details of the solutions used are given.
- Absorbance values are presented in Table 3.
- Adsorption density based on the previous results is presented in Table 4.
- The aim is to calculate concentration (Cf) values, evaluate adsorption density, and create adsorption isotherms; interpret the curves created.
Next Week
- Lab 4, UV-Visible Adsorption Experiment, is scheduled for December 20th, 9:00 AM -11:20 AM
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Description
Test your knowledge on the properties of solid-liquid interfaces and the process of adsorption in surface and colloid chemistry. This quiz covers key concepts including adsorbates, adsorbents, and the implications of adsorption in various contexts. Join Dr. Orhan Ozdemir in exploring this fascinating field!
