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Teknik BioseparasiDina Wahyu

Genap/ Maret 2014

OutlineChemical Reaction Engineering

Pendahuluanmempelajari ruang lingkup teknik bioseparasi dan teknik “cel disruption”

Teknik Pemisahan Secara Fisika 2Mempelajari teknik pemisahan sedimentasi

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2

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Teknik Pemisahan Secara Fisika 1Mempelajari teknik sentrifugasi pada bioseparasi

Koagulasi dan flokulasi Mengetahui teknik pemisahan dengan cara koagulasi dan flokulasi

Teknik Pemisahan Secara Fisika 3 Mempelajari teknik filtrasi pada bioseparasi

Adsorpsi Proses adsorpsi pada cairan dan gas, serta pengetahuan bahan adsorpsi

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Adsorpsi 2Kinetika Adsorpsi, Isotherm Adsorption7

Methods of PurificationDescribe methods of separation for the components of the following types of mistures:

(i) solid-solid(ii) solid-liquid(iii) liquid-liquid(miscible)

Techniques to be covered for separations and purification include:

(i) Use of a suitable solvent, filtration and crystallization or evaporation

(ii) Distillation and fractional distillation(iii) Paper chromatography

Pure Substances & MixturesA pure substance contains only one type of

substance, and is not mixed with any other substance.

Are the following pure substances or mixtures?Are the following pure substances or mixtures?• Clean tap water• 100% orange juice• Distilled water

mixture

mixture

Pure substance

Methods of PurificationSome terms :

• Solute - the solid that dissolves• Solvent - the liquid that does the dissolving• Solution - solid + solvent• Residue - the insoluble solid trapped in the filter • Residue - the insoluble solid trapped in the filter

paper• Filtrate - the liquid that passes through the filter

paper• Sublimate - the condensed solid produced during

sublimation

Methods of PurificationThe particular method used for separating

any given mixture depends on the nature (eg. solubility, physical state) of its constituents.

Filtration• Used to separate a solid from a liquid in

which the solid is insoluble

residuemixture of solid and

liquid

filter paper

filter funnel

residueliquid

filtrate

Principle of Filtration

• The separation works only if the particles concerned

are of different sizes, such as larger particles of an

insoluble solid and smaller particles of a liquid or

solution.solution.


The filter material acts as a sieve which allows

the smaller particles to pass through and

keeps the bigger particles behind.


Can a mixture of common salt and water

be separated by filtration? Why?

Filtration - large scale use

• Sand filters used in water treatment plants to

remove solid impurities

• Dissolved substances and bacteria will not be

removed

Decanting• Separates an insoluble solid from a liquid

• liquid is carefully poured away from the solid

which is usually heavier and settles at the

bottom of the container. bottom of the container.

Evaporation (Heating )to Dryness

• used to recover a soluble solid from its solution

• Only for solids that will NOT decompose on heating.heating.

• Eg. sodium chloride (common salt) from salt solution

Crystallisation• used to recover a soluble solid from its solution• for solids that decompose on heating• Eg. Copper(II) sulphate and most other salts

Steps :• The solution is heated (evaporated) to saturation • The solution is heated (evaporated) to saturation point OR ‘heated to remove most of the solvent’

• The saturated solution is left to cool; crystals are formed.

• The crystals are removed by filtration. To purify the crystals, they can then be washed with cold distilled water and dried between filter papers.

Crystallisation - the Principle behind

• Substances are usually more soluble in hot water than cold water eg. more copper(II) sulphate will dissolve in water at 80ºC than at 30 ºC.

• When the hot saturated solution is cooled, the • When the hot saturated solution is cooled, the cooled solution is unable to hold as much solute as when it was hot. The extra solute that cannot remain dissolved appears as crystals.

Solubility & Crystallisation

Solubility data for NH4Cl in grams/100 mL H2O • 30oC - 41.4 g • 50oC - 50.4 g • 70oC - 60.2 g • 90oC - 71.3 g • 90oC - 71.3 g

If the water was heated to 90°C, how much of the solute will be able to dissolve?If this hot solution is then cooled to 30 °C, how much solute can the water contain now?Hence what is the mass of crystals you would expect to obtain?

Separating a mixture of solids

Method used depends on the nature of the solids :-(1) If the mixture of solids behave differently in a

particular solvent , that is, one component is soluble in it while the other is insoluble…

carefully choose a solvent that will dissolve only one of the solids

Egs. common salt and sand; naphthalene and sand

Use water as solvent

Use methylated spirits as solvent


Basic Steps :

Dissolution Filtration

Evaporation to dryness

OR

Crystallisation

OR


(2) Sublimationused when one of the

solid sublimesEg. Eg.

• mixture of iodine + copper;

• mixture of ammonium chloride +sodium chloride


(3) Other methods :

• make use of the special properties of the substance

Eg. mixture of iron filings and sulphur …. Eg. mixture of iron filings and sulphur …. …use a magnet

• Bring a magnet to the mixture.

• The iron filings will be attracted to the magnet while the sulphur will be left behind.

Separating the Solvent from the Solution

solute solvent

Crystallisation

Evaporation to dryness

Distillation

solute solvent

solution

Simple Distillation• Some Terms Used :

• Distillate - the liquid that distils over• Miscible liquids - liquids that mix completelyto form a single layer

• Immiscible liquids - liquids that do not mix• Immiscible liquids - liquids that do not mix• A solvent can be separated from a solution and

collected by simple distillation.

Principle of Distillation

A liquid boils and turns into vapour at its

boiling point.

When the vapour is condensed, the (pure) liquid

is obtained again.

Simple Distillation

flask

thermometer

2. .. vapourise. The vapour rises up the flask

3. the condenser is cold, sothe vapour condenses to liquid water.

flask

sea water

1. Solution is heated, causing the solvent to …

condenser

distillate

Boiling chips4. Pure water drips into the beaker. It is distilled water.

Simple Distillation

flask

thermometer

Water outflask

sea water condenser

Boiling chips

Water in

To maintain even boiling, with not too much bumping

Liebig Condenser

Vapour entersCondensed vapour in liquid

form (distillate) leaves

Cold water in

Water out

Direction of water flow

Water flows in anti-current to the flow of vapour.

Liebig Condenser

Vapour entersCondensed vapour in liquid

form (distillate) leaves

Cold water in

Water out

Direction of water flow

This is to make sure the coldest part of the condenser is just before the vapour escapes.

Simple DistillationSimple distillation can be used to obtain

• from salt solution• from copper(II) sulphate solution• from a solution of sugar in ether

waterwater

ether

Note : The liquid that distils over is called the distillate . The solid that remains in the flask is called the residue .

Simple Distillation

Qns. : Where is the thermometer placed? What is the reason for this?

thermometer

flask

sea water condenser

distillate

Boiling chips

Simple DistillationThermometer placed at the side arm of the flask so

that it records the temperature of the vapour as it enters the condenser.

thermometer

flask

sea water condenser

distillate

Boiling chips

Separating miscible liquids -Fractional distillation

• miscible liquids can only be separated by fractional distillation if they have different boiling points . different boiling points .

• Eg. mixture of ethanol and water.


thermometer

Water out

condenser

Fractionating column

flask

mixture of ethanol and water

Water indistillate

Boiling chips

Separating miscible liquids -Fractional distillation2. The fractionating column is

packed with glass beads to increase its surface area. Vaporisation followed by

condensation takes place many times as the vapour is

3. Eventually, the liquid with the lower boiling point reaches the top and distils over.

1. When heated, the liquid with the lowerboiling point will vaporize more readily.

many times as the vapour is swept upwards.


4. The temperature stays constant at 78°C.

When all the ethanol has distilled over, the

temperature reading rises above 78°C. At

5. The receiver is changed to collect each distillate separately.

rises above 78°C. At 100°C, water starts to

distil over.


Sketch a graph of temperature versus time to show the changes in temperature readings throughout the distillation.

temperature

time

78°C

100°C


Note : • The glass beads in the

fractionating column provides a large surface area so that condensation occurs more

glass bead

s

condensation occurs more readily.

• The liquid with the lowerboiling point distils over first, followed by the liquid with the next higher boiling point.


Note : • If the liquids in the mixture

have the same boiling point, fractional distillation is not possible.

glass bead

s

possible.• If the difference in boiling point

is great, fractional distillation occurs readily.

Fractional distillation -applications

• Fractional distillation can be used to separate :-• nitrogen and oxygen from liquid air• nitrogen and oxygen from liquid air

• the components of crude oil

• ethanol from fermented liquor

Fractional distillation of crude oil

Separating immiscible liquids

• A separating funnel can be used to separate two immiscible liquids. • Eg. water and petrol.• Eg. water and petrol.

• This method can be used to separate :• a mixture of petrol and

water• engine oil and water

The main points so far…Mixtures

solid + solidsolid + liquid

(Solid INSOLUBLE in (Solid INSOLUBLE in liquid)liquid)

liquid + liquid

Residue(solid)

Filtrate(liquid)

Filtration

liquid)liquid)


solid + solidsolid + liquid

(Solid SOLUBLE (Solid SOLUBLE in liquid)in liquid)

liquid + liquid

Residue

(solid/ solute)

Distillate

(liquid/ solvent)

Simple Distillation

in liquid)in liquid)


solid + solid

solid + solution Difference in

solubility?

YES

liquid + liquid

Residue(insoluble

solid)

Filtrate(solution)

Filtration

solubility?Add suitable solvent

CrystallisationCrystals(soluble

solid)


solid + solid

solid + solution Difference in

solubility?

YES

liquid + liquid

Filtration

solubility?Add suitable solvent

NO

Other physical difference?

Sublimation

Using magnetEgs.

Crystallisation


miscible liquids

(different boiling

immiscible liquids

liquid + liquid

Fractional distillation

boiling pts.)

liquids

Separating funnel

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