Anion Exchanger

M. Awais Yaqoob

2011-ch-32

(University of Engineering and Technology, Lahore)

Outline

Background Why an anion exchanger? Alternatives Design Resins Cost of chosen design Questions

Background

Ions are electrostatically bound to an insoluble and chemically inert matrix – Anion exchangers bear positively charged

functional groups that bind negatively charged particles.

During elution the anion exchanger can be described by the following chemical equation:

Why an anion exchanger?

Assumptions

•Denatured insulin had a 0% binding efficiency

•Insulin-Ester had a 100% binding efficiency and 90% recovery

•Isoelectric point of Denatured Insulin is higher than Insulin-Ester

ComponentFlowrate (kg/batch)

Mass Percent (%)

Conc.

(g/L)

Denatured Insulin 0.4359 0.03 0.30

Insulin-Ester 296.38 20.22 202.25

Water 1168.65 79.75 797.46

Anion Exchanger Advantages

Capable of handling large volumes

Efficient, precise separation

– Accurate separation of Insulin ester and denatured Insulin

1

Large pressure drop– Require expensive pumps

High resolution requires small beads– Small beads decrease flow rate

Each cycle requires several stages– Charging, sample input, washing, elution,

cleaning

Anion Exchanger Disadvantages

Alternatives

Membrane Chromatography Exclusion Chromatography Affinity Chromatography

2 3 4

Membrane Chromatography

Allows for much larger throughput (about 100 times that of ion exchange) and a higher efficiency

Uses microporous membrane Small pressure drop compared to traditional

ion exchangers Scaling up separation is simplified

Exclusion Chromatography

Separates on basis of Molecular Mass

Column is filled with semi-solid beads of a polymeric gel

– The porosity of the gel can be changed as to exclude molecules of a set size

Useful for samples containing many types of proteins

5

Affinity Chromatography

Matrix anchored ligand– Specifically binds to

protein of interest

Can exploit protein’s unique biochemical properties instead of charge in ion exchange

Requires low flowrates

8

Anion Exchanger Design

Ergun Equation for pressure drop in a packed bed

1

ReA

QDp

75.1Re

150Pf

1

2

P

solutionp

D

AQLf

P

Design Considerations

Property Dimension

Bead Diameter, DP 35μm

Column Lenth, L 3.47m

Column Diameter, D 1.3 m

Pressure Drop, ΔP 1718 kPa

Void Fraction, ε 0.4

Vessel Volume 4604 L

All constants were taken from Perry’s Chemical Engineering Handbook7

Vessel Sizing

Exchanger is very large– Much larger than needed, however, this will save

on pumping costs

Total flow rate through the anion exhanger is 1.721 x 10-5 m3/s– Based on 80h batch time and 826kg/batch– Scaled up by a factor of 6

Vessel Schematic

P&ID

1

Resins

Serves as the media for stationary phase– Polymeric matrix with immobilized charged

functional groups

Quaternary Ammonium functional group Diethylaminoethane functional group Can be regenerated in the columns and

used for many production cycles – anionic resin: 500 - 1,000 cycles

8

Estimated Costs for Anion Exchanger

Unit Cost/Unit # of Units Total

Anion Exchanger $261,000 1 $261,000

Resin ~9 $/L 110 $910

Peripheral Equip. $50,000 N/A $50,000

Shipping $2,000 1 $2,000

Installation $100,000 N/A $100,000

Controls/Software $25,000 1 $25,000

Total Equip. Cost $438,910

Estimated Operation Costs / Year

Operation Total

Utilities $10,000

Maintenance $5,000

Supplies $1,000

Total Operations $16,000

*Overhead costs, taxes and insurance costs have not been included in this estimate

The total cost associated with the purchase of an Anion Exchanger with one year of operation is approximately $454,910.

References

[1] PowerMax, 2006

http://www.usfilter.com/

[2] Pall Corporation, 2006

(http://www.pall.com/datasheet_biopharm_36585.asp)

[3] Protein Chemistry, 2006

(http://fig.cox.miami.edu/~cmallery/255/255tech/255techniques.htm)

[4] Voet & Voet Biochemistry 3rd Edition, Wiley, 2004

[5] Waters Corporation, 2006 (http://www.waters.com/watersdivision/)

[6] Novasep Technologies, 2006

(http://www.novasep.com/technologies/ion-exchange.asp)

[7] Graver Technologies, 2006

(http://www.gravertech.com/pdfs/literature/ionex/IonExchangeResinSelection.pdf)

[8] OR-Live, 2003

http://www.biopharminternational.com/

Questions ?