Hollow Fiber Supported Liquid Membrane for the Separation and it's application.

1. Presented by,
KANCHAN D. RAMTEKE
MT17MCL011
Hollow Fiber Supported Liquid Membrane for the Separation/
Concentration of Gold(I) from Aqueous Cyanide Media

2. CONTENT
Introduction
Experimental Procedure
Theoretical Background
Results
Conclusion
Abstract
Poster

3. Module :3 Membrane based separation processes Dr. Sirshendu De Professor, Department of Chemical Engineering Indian Institute of Technology, Kharagpur
https://en.wikipedia.org/wiki/Semipermeable_membrane
Definition of a membrane:
It is an interface that separates the two phases and restricts the transport of various chemical species through it.
Semipermeable membrane:
A semipermeable membrane is a type of biological or synthetic, polymeric membrane that will allow certain
molecules or ions to pass through it by diffusion or occasionally by more specialized processes of facilitated diffusion,
passive transport or active transport.

4. What is membrane separation????
Membrane separation is a technology
which selectively separates (fractionates)
materials via pores and/or minute gaps in
the molecular arrangement of a
continuous structure. Membrane
separations are classified by pore size and
by the separation driving force.
http://www.smartmembranesolutions.co.nz/membrane-classifications/
https://www.asahi-kasei.co.jp/membrane/microza/en/kiso/kiso_1.html

5. Terms Used:
Permeate Retentate Permeability Retention

6. History of liquid membranes
1967 – Ward
&Rob:
Immobilized
liquid
membranes
1968 – Lee:
Emulsion liquid
membranes
1977 – Goddard:
Models of facilitated
transport
1980 – Leblanc:
The membranes with
builded-in carriers.
Facilitated transport.
1983 –
Kuo&Gregor:
Thin film liquid
membranes

7. Liquid
Membranes:-
A liquid acting as a semipermeable barrier between
two fluid phases.
Driving Force:- Solute concentration gradient. (in most cases)
Mechanism:- Solution-diffusion (sometimes also chemical reaction)
Liquid
Membrane
Transport
Liquid-Liquid extraction (LLX) and membrane
separation in one continuously operating device.
http://www.etseq.urv.es/assignatures/ops/presentacio_membranes.pdf

8. Three groups of
liquid membranes
1. Bulk liquid
membrane (BLM)
2. Supported liquid
membrane (SLM) or
immobilized liquid
membrane ( ILM)
3. Emulsion liquid
membrane (ELM)

9. F- Source or feed phase
E- Liquid membrane
R- Receiving phase.
Liquid Membranes Principles and Applications in Chemical Separations and Wastewater Treatment Elsevier Editor- Vladimir S. Kislik Page No. 04
Hollow-fiber-supported-liquid-membrane-system

10. Application Liquid
membranes
Biotechnological and environmental sciences
Recovery of zinc from wastewater in the viscose fiber industry
Recovery of nickel from electroplating solutions
Biomedical and analytical fields
Hydrometallurgical processes
SEPARATION PROCESS PRINCIPLES Chemical and Biochemical Operations THIRD EDITION J. D. Seader Page No. 501 Table 14.1 (8)

11.  The world’s gold is produced by hydrometallurgical techniques including combinations of leaching,
adsorption, and electro-winning or precipitation steps.
 The gold is extracted from the ore using a basic cyanide solution with a leaching reaction described as
 Cyanidation (also known as the cyanide process or the MacArthur-Forrest process) is a hydrometallurgical
technique for extracting gold from low-grade ore by converting the gold to a water-soluble coordination
complex
 One of the most effective leaching alternatives is the use of cyanidation.
 Cyanidation leaching steps are combined with subsequent steps of gold cyanide adsorption with activated
carbon.
 Drawbacks
• Lack of selectivity due to the presence of mixtures of other metal cyanides when adsorbed on activated
charcoal.
• Its complexity through involving a multistep scheme for separation.
INTRODUCTION

12. Advantage
High mass-transfer rates of solutes
high selectivity by the use of extractant LIX 79
The capacities of performing selective metal extraction
and treating dilute solutions make the HFSLM
technique an attractive alternative to solvent extraction
in that it combines the processes of extraction stripping
and regeneration in a single step (HFSLM).
As compared with solvent extraction, HFSLMs are
characterized by
Being rapid in
separation
High in
efficiency
Low in power
consumption
Adaptable to
diverse uses.
Hollow fiber supported liquid membranes (HFSLMs)

13. Experimental Procedure
A stock solution
of Au(I) (5 g/L)
was prepared
from pure solid
KAu(CN)2
1 g/L of each
cyanide salt such
as KAg(CN)2,
Zn(CN)2,
KNi(CN)4, and
CuCN,
K4Fe(CN)6.3H2O,
NaCN were
dissolved in
NaCN.
KNi(CN)4 and
CuCN salts were
dissolved in
excess NaCN in
deionized water.
The organic
solvent used in
the liquid
membranes was
n-heptane.

14. HFSLM Preparation and Methods
• Hollow fiber:- Microporous hydrophobic
polypropylene
• Impregnation of the solvents on the
polymeric support was carried out by
pumping the organic solvents through the
fiber bore for 1 h at a slow flow rate.
• The module was run in recycling mode.
• Feed containing Au(I) in alkaline cyanide
media and strip (0.4-1 M NaOH) solutions
are recirculated in stirred reservoirs.
Schematic view of hollow fiber supported liquid
membrane run in the recycling mode
1- hollow fiber contactor
2- feed pump
3- strip pump
4- feed reservoir
5- strip reservoir

15. Theoretical Background
 To model the recycling mode, in 1984 Danesi6a proposed a simple model with a constant permeation
coefficient.
 The model for the transport of Au(I) in a hollow fiber supported liquid membrane system operating in a
recycling mode consists of four equations describing
• the change of the Au(I) concentration in the feed and stripping streams when circulating through
the membrane module and
• the change of the Au(I) concentration in the feed and stripping tanks, where the aqueous solutions
are continuously recirculated, based on the complete mixing hypothesis.
 Assumptions
• linear concentration gradients
• the lack of back-mixing

16. For the feed solution
Module mass balance
C is the solute concentration (g/cm3),
L is the fiber length (cm),
Q is the flow rate (cm3/s),
ʋ is the linear velocity (cm/s), and
V is the tank volume (cm3).
The subscripts f and s refer to the feed
and stripping solutions, respectively.
The superscripts m and T refer to the
membrane module and phase tank,
respectively.
A/Vm is the ratio of the area of the
volume of mass transfer of the fiber
tank mass balance
for the stripping solution
module mass balance
tank mass balance

17. for the feed phase circulating through the inside of the fiber
for the stripping phase circulating along the outside of the fiber
where
nf is the number of fibers
contained in the membrane
module,
Rc is the inner radius of the
module cell, and
ri and ro are the inner and outer
radii of the hollow fiber,
respectively
When a sodium hydroxide solution is used as the stripping agent, an
instantaneous reaction is assumed to occur on the outside of the fiber,
leading to CS
M=0 and CS
T=0
Experimental results can thus be fitted to a first-order
kinetic law

18. The overall permeability coefficient
S is the factor dependent on the geometry of
the fibers and the module
Overall permeability coefficient PAu centers on three mass-transfer resistances.
• One of them occurs in the liquid flowing through the hollow fiber lumen.
• The second corresponds to the gold-complex diffusion across the liquid membrane immobilized on
the porous wall of the fiber.
• The third resistance is due to the aqueous interface created on the outside of the fiber.
where rlm is the hollow fiber log mean radius
ki and ko are the interfacial coefficients
corresponding to the inner and outer aqueous
boundary layers.
Pm is the membrane permeability,

19. Partition coefficient of gold (Dr)
When the reaction is instantaneous on the stripping side

20. Results
HFSLM System. Feasibility Studies
To obtain stable HFSLM, an aliphatic diluent, n-heptane, was selected as diluent.
Concentration courses obtained
from the feasibility study
Stability analysis of the HFSLM
system investigated in n-heptane.
The experimental results, showing that the transport rate of Au(I) is held constant during the time period considered.

21. Influence of the Concentration of the Aqueous Phases and Hydrodynamics
The Au-(I) ions in alkaline cyanide media (present as Au(CN)2-) form a complex (ion-pair type) with the
extractant LIX 79 (N,N¢-bis(2 ethylhexyl)guanidine, RH), expressed as
Dr values fall in the same range for the gold concentration
Permeability coefficient was independent of initial metal
concentration
Lower concentration of NaOH (0.1-0.2 M) affected recovery of
gold in the receiving phase, and hence a higher concentration
was used.

22. Conclusions
The hollow fiber supported liquid membrane technique was found to be a promising for the simultaneous
separation and concentration of Au(I) from alkaline cyanide media in the presence of other metal
cyanides such as Ag(CN)2-, Cu(CN)4
3-, Ni(CN)4
2-, and Fe(CN)6
4- using LIX79 in n-heptane.
The use of LIX79/n-heptane immobilized on polypropylene hollow fiber resulted in systems whose
stabilities were experimentally tested for long operation times (up to 200 h) for efficient Au(I) removal.
The use of stripping solution containing NaOH provided efficient and fast stripping of Au(I) in receiving
(product) solutions.
A good selectivity was found, and the separation factors based on the experimental results obtained for
the cyanoions by 12% (v/v) LIX79 give the following order of selectivity:
Au(CN)2 Ag(CN)2 Ni(CN)4
2-, >Cu(CN)4
3-, >Fe(CN)6
4-.

24. Hollow Fiber Supported Liquid Membrane for the Separation/Concentration
of Gold(I) from Aqueous Cyanide Media
Kanchan D. Ramteke
Visvesvaraya National Institute of Technology
Introduction
 The world’s gold is produced by hydrometallurgical techniques including combinations of leaching,
adsorption, and electro-winning or precipitation steps.
 The gold is extracted from the ore using a basic cyanide solution with a leaching reaction described
as
 Cyanidation (also known as the cyanide process or the MacArthur-Forrest process) is a
hydrometallurgical technique for extracting gold from low-grade ore by converting the gold to a
water-soluble coordination complex
 One of the most effective leaching alternatives is the use of cyanidation.
 Cyanidation leaching steps are combined with subsequent steps of gold cyanide adsorption with
activated carbon.
Advantage of Hollow fiber supported liquid membranes (HFSLMs)
• High mass-transfer rates of solutes
• high selectivity by the use of extractant.
• The capacities of performing selective metal extraction and treating dilute solutions make the HFSLM
technique an attractive alternative to solvent extraction in that it combines the processes of extraction
stripping and regeneration in a single step (HFSLM).
Experimental Procedure
• A stock solution of Au(I) (5 g/L) was prepared from pure solid KAu(CN)2
• 1 g/L of each cyanide salt such as KAg(CN)2, Zn(CN)2, KNi(CN)4, and CuCN, K4Fe(CN)6.3H2O,
NaCN were dissolved in NaCN.
• KNi(CN)4 and CuCN salts were dissolved in excess NaCN in deionized water.
• The organic solvent used in the liquid membranes was n-heptane.
HFSLM Preparation and Methods
• Impregnation of the solvents on the polymeric support was carried out by pumping the organic
solvents through the fiber bore for 1 h at a slow flow rate.
• The module was run in recycling mode.
• Feed containing Au(I) in alkaline cyanide media and strip (0.4-1 M NaOH) solutions are recirculated
in stirred reservoirs.
Theoretical Background
 To model the recycling mode, in 1984 Danesi6a proposed a simple model with a constant permeation
coefficient.
 The model for the transport of Au(I) in a hollow fiber supported liquid membrane system operating
in a recycling mode consists of four equations describing
• the change of the Au(I) concentration in the feed and stripping streams when circulating
through the membrane module and
• the change of the Au(I) concentration in the feed and stripping tanks, where the aqueous
solutions are continuously recirculated, based on the complete mixing hypothesis.
Results and Conclusion
The hollow fiber supported liquid membrane technique was
found to be a promising for the simultaneous separation and
concentration of Au(I) from alkaline cyanide media in the
presence of other metal cyanides such as Ag(CN)2-, Cu(CN)4
3-,
Ni(CN)4
2-, and Fe(CN)6
4- using LIX79 in n-heptane
The use of LIX79/n-heptane immobilized on polypropylene
hollow fiber resulted in systems whose stabilities were
experimentally tested for long operation times (up to 200 h) for
efficient Au(I) removal.
References
https://en.wikipedia.org/wiki/Semipermea
ble_membrane
SEPARATION PROCESS PRINCIPLES
Chemical and Biochemical Operations