EXTRACTION
Unit Operasi 2014
Extraction → a separation process, based on
differences in solubility
• Extraction is one of the most useful and widely
used chemical separation methods.
• There are two types of extraction process:
• Solid – Liquid Extraction
(termasuk Supercritical Fluid Extraction)
• Liquid – Liquid Extraction
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Solid-liquid Extraction (leaching)
a solute is extracted from a solid phase with
the help of a solvent.
Contoh:
ekstraksi kopi dari biji kopi pada pembuatan kopi
instan
ekstraksi senyawa antimikroba dari berbagai jenis
daun
ekstraksi kalsium oksalat dari tepung porang
(pemurnian/pencucian tepung porang)
Mekanisme Leaching
keterangan :
1. pelarut, 2. padatan (mengandung komponen terlarut),
3. komponen terlarut, 4. padatan (tidak mengandung
komponen terlarut), 5. komponen terlarut dalam pelarut
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Mekanisme Leaching
komponen terlarut yang terperangkap di dalam padatan,
bergerak melalui pori-pori padatan
komponen terlarut berdifusi keluar permukaan partikel
padatan dan bergerak ke lapisan sekitar padatan,
selanjutnya ke larutan
Proses ekstraksi padat-cair
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Multistage Extraction
Liquid-liquid Extraction
Liquid extraction (or solvent extraction) merupakan
operasi dimana komponen terlarut dipisahkan dengan
menambahkan pelarut cair yang sesuai.
• Pada operasi ini, pemisahan komponen bergantung pada
perbedaan distribusi komponen terlarut diantara dua
fase cairan.
• The mass transfer of the solute liquid takes place
from the feed solution to the solvent phase.
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Basic Steps
Typical liquid-liquid extraction operations utilize
the differences in the solubilities of the
components of a liquid mixture. The basic steps
involved include:
1. Contacting the feed with the extraction solvent.
2. Separation of the resulting phases
3. Removal/recovery of solvent from each phase.
Liquid-liquid extraction is a useful method to separate components
(compounds) of a mixture
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The concept of liquid-liquid extraction
Liquid-liquid extraction is based on the transfer of a solute
substance from one liquid phase into another liquid phase
according to the solubility.
Extraction becomes a very useful tool if you choose a suitable
extraction solvent.
You can use extraction to separate a substance selectively
from a mixture, or to remove unwanted impurities from a
solution.
In the practical use, usually one phase is a water or waterbased (aqueous) solution and the other an organic solvent
which is immiscible with water.
The success of this method depends upon the difference in
solubility of a compound in various solvents. For a given
compound, solubility differences between solvents is quantified
as the "distribution coefficient"
Partition Coefficient / Distribution Coefficient (K)
When a compound is shaken in a separatory funnel with two
immiscible solvents, the compound will distribute itself between
the two solvents.
Normally one solvent is
water and the other solvent
is a water-immiscible
organic solvent.
Most organic compounds
are more soluble in organic
solvents, while some organic
compounds are more soluble
in water.
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(1) If there are 30 particles
of compound, these are
distributed between equal
volumes of solvent1 and
solvent2.
(2) If there are 300
particles of compound , the
same distribution ratio is
observed in solvents 1 and 2
(3) When you double the
volume of solvent2 (i.e., 200
mL of solvent2 and 100 mL of
solvent1),
the 300 particles of
compound distribute as shown
If you use a larger amount of extraction solvent, more solute is
extracted
An additional 67 particles are
extracted with the second portion
of extraction solvent
(solvent2).The total number of
particles extracted from the first
(200 particles) and second (67
particles) volumes of extraction
solvent is 267.This is a greater
number of particles than the
single extraction (240 particles)
using one 200 mL portion of
solvent2!
It is more efficient to carry out
two extractions with 1/2 volume
of extraction solvent than one
large volume!
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If you extract twice with 1/2 the volume, the extraction is more
efficient than if you extract once with a full volume. Likewise,
extraction three times with 1/3 the volume is even more efficient….
four times with 1/4 the volume is more efficient….five times with 1/5
the volume is more efficient…
The greater the number of small extractions, the greater the
quantity of solute removed. However for maximum efficiency the
rule of thumb is to extract three times with 1/3 volume
Supercritical Fluid Extraction
Supercritical fluid extraction (SCFE or SFE) is an extraction
process carried out using a supercritical fluid as a solvent.
A supercritical fluid (SCF) is a substance at a temperature and
pressure above those of the critical point.
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The density of supercritical fluids is close to that of the
liquid while their viscosity is low and comparable to that of
a gas. These two properties are the key to the functionality
of SCFs as extractants.
The relatively high density imparts to SCFs good
solubilization power while the low viscosity results in
particularly rapid permeation of the solvent into the solid
matrix.
Karbon dioksida (CO2) merupakan pelarut yang paling
umum digunakan dalam SFE.
Pertimbangan penggunaan CO2 :
segera dapat dipisahkan dari bahan yang dilarutkan
viskositas rendah, difusifitas tinggi, tidak berwarna, dan
tidak mencemari lingkungan
tidak mudah terbakar dan tidak mahal
memiliki temperatur kritis 31 oC, sehingga sesuai untuk
bahan yang sensitif thd panas
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SFE System
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TEKNOLOGI DAN APLIKASI SFE
1. EKSTRAKSI MINYAK MAKAN
Keuntungan ekstraksi dengan CO2 :
Non toxic
Mudah dipisahkan dari minyak yang diekstrak
Minyak berkualitas tinggi
Tidak memberikan pengaruh yang besar terhadap
perubahan komponen gizi lainnya
Ekstraksi minyak dari biji bunga matahari
(canola)
Kondisi yang diberikan sbb :
berat biji bunga matahari : 4 gram
suhu ekstraksi : 400C
tekanan ekstraksi : 35 Mpa
Ekstraksi minyak dari dedak
Kondisi yang diberikan sbb :
berat dedak : 150 gram
suhu ekstraksi : 350C, ~ 5 jam
tekanan ekstraksi : 4350 Psi
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Ekstraksi minyak dari mesokarp (daging buah)
Kondisi yang diberikan sbb :
berat serpihan mesokarp : 400 – 500 gram
suhu ekstraksi : 400C
tekanan ekstraksi : 3000 – 3500 Psi
2. Dekafeinasi Kopi
Keuntungan: bebas residu pelarut
Contoh soal:
Suatu sampel mengandung komponen X sebanyak 350 partikel.
Sampel tersebut memiliki volume 1 dm3. Untuk mengekstrak
komponen X dari sampel ditambahkan pelarut etanol sebanyak
100 cm3. Komponen X dalam sampel 5 kali lebih terlarut dalam
etanol daripada sampel.
1. Hitung berapa jumlah partikel yang didapatkan dengan
ekstraksi 1 tahap!
2. Hitung berapa jumlah partikel yang didapatkan dengan
ekstraksi 2 tahap (masing-masing tahap menggunakan ½ dari
total pelarut)
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Suatu sampel mengandung komponen X sebanyak 250 partikel.
Sampel tersebut memiliki volume 1 dm3. Untuk mengekstrak
komponen X dari sampel ditambahkan pelarut etanol sebanyak 100
cm3. Komponen X dalam sampel 6 kali lebih terlarut dalam etanol
daripada sampel.
1. Hitung berapa jumlah partikel yang didapatkan dengan ekstraksi 1
tahap!
2. Hitung berapa jumlah partikel yang didapatkan dengan ekstraksi 2
tahap (masing-masing tahap menggunakan ½ dari total pelarut)
TERIMAKASIH
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