The document summarizes an internship report on reverse osmosis membrane preparation. It discusses the Institute of Chemical Technology Mumbai where the internship took place. It then describes the reverse osmosis process and interfacial polymerization reaction used to prepare polyamide RO membranes. It presents a probability equation derived to model amine molecule behavior during interfacial polymerization. Finally, it outlines the thin film composite membrane preparation process and concludes with noting the role of RO membranes and contribution made in deriving the probability equation.

1. Presented by:
SHIVAM KAUSHIK
CHEMICAL ENGG.
IT,GGV
BILASPUR
INTERNSHIP REPORT

2. • About ICT Mumbai.
• Brief description: Reverse osmosis process.
• Calculative description : Probability equation for interfacial polymerization at
interface.
• Preparation of RO membranes.
CONTENT

3. • The Institute of Chemical Technology (ICT) Mumbai was established as the Department of Chemical Technology on
1st October, 1933 by the University of Mumbai, through active support of industries and philanthropists. The
Institute was most popularly known as UDCT, Mumbai.
• Research has been an integral part of ICT since its inception and it has created over 500 first generation
entrepreneurs. The UDCT grew significantly in stature and was granted autonomy under UGC regulations by the
University of Mumbai.
• Due to the recommendations of the Government of Maharashtra and University of Mumbai, the ICT was granted
Deemed University Status by the MHRD on 12th September, 2008, with all provisions of the UGC for funding and
support as the state owned deemed university.
• Biospectrum magazine in August 2010 has also rated ICT’s programme as Number One among all biotechnology
programmes in the country and the first prize was bestowed on 17th December at Bangalore.
• A survey was published by Professor Jude Sommerfeld of Georgia Tech., USA in January 2011 showing that the ICT
is Number One Institute in India far ahead of several others including IITs, and it is also in top 10 in the world in
Chemical Engineering. This rank has been maintained since 1970.
About ICT,Mumbai.

4. • Reverse osmosis is a water purification technology that uses a semi permeable
membrane to remove dissolved solids from drinking water.
• In reverse osmosis , an applied pressure is used to overcome osmotic pressure that is
driven by chemical potential.
• The result is that the solute is retained on the pressurized side of the membrane and
the pure solvent is allowed to pass to the other side.
Reverse osmosis

5. • What is interfacial polymerization ???
Interfacial polymerization is a step growth polymerization occurs at the interface between an
aqueous solution containing one monomer and an organic solution containing a second monomer.
Interfacial polymer growth from TMC and MPD is depicted below:
Relative probability equation of an amine molecule for
interfacial polymerization with TMC during preparation of a
polyamide RO membrane,

6. For a simple case of interfacial polymerization involving
dissolved monomer, the schematic can be depicted as :
Random presence of diamine molecule in aqueous phase and TMC in organic phase.

7. • Gaussian random walk phenomenon is considered .
• A random walk is a mathematical formalization of a path that consists of a succession
of random steps.
• In simple symmetric random walk on a locally finite lattice, the probabilities of the
location jumping to each one of its immediate neighbor are the same.
• Some random walks are on graphs, others on the line, in the plane, in higher dimensions,
or even curved surfaces, while some random walks are on groups.
• Random walks also vary with regard to the time parameter.
To find the probability of amine particles to reach at interface ,following assumptions are
made :

8. • Only those particles are which are reaching the surface within 20
seconds are considered.
Let ‘d’ be the vertical distance of particle from the interface and ‘x’ be the horizontal
distance of particle from a reference point ‘o’. Therefore, the radial distance ‘r’ is equal
to 𝑥2 + 𝑟2. Since point ‘o’ is considered as reference so its coordinates will be (0,0,0)
Thus, variance, 𝜎2 is given by:
𝜎2 = <(𝑟 − 𝑟 𝑚𝑒𝑎𝑛)2>
= <(𝑟2 + 𝑟 𝑚𝑒𝑎𝑛
2 − 2𝑟𝑟 𝑚𝑒𝑎𝑛)>
= <𝑟2>- 2 <r> 𝑟 𝑚𝑒𝑎𝑛+𝑟 𝑚𝑒𝑎𝑛
2
= <𝑟2> - 𝑟 𝑚𝑒𝑎𝑛
2
But for Random walk, 𝑟 𝑚𝑒𝑎𝑛=0

9. 𝜎2
= <𝑟2
Now, <𝑟2> = 6Dt {D = diffusivity, t = time}
So, 𝜎2
= 6Dt ….(1)
Thus, the probability equation can be written as:
P(r) =
1
2𝜋𝜎2
exp(
−𝑟2
2𝜎2) ….(2)
Doing it in the cylindrical coordinates
Equation 2 can be written as
= 0
π
2
∅=0
2π
r=0
∞ 1
2πσ2
exp (
−r2
2σ2)
dA cosθ
4πr2 ρr2
sinθdrdθd∅ ....(3)
=
ρdA
2 2πσ2 0
∞
exp(
−r2
2σ2)dr 0
π
2
dθ
2
sin2θ ….(4)
=
ρ
4 2πσ2 0
∞
exp(
−r2
2σ2) ….(5)

10. Since, 𝜌𝑠 >> 𝜌
Thus, the probability of amine molecule to come at the interface is given by
P(amine) =
𝝆
𝟒 𝟐𝛑𝝈 𝟐 𝟎
∞
𝒆𝒙𝒑(
−𝒓 𝟐
𝟐𝝈 𝟐)
𝝆
𝒔+
𝝆
𝟒 𝟐𝛑𝝈 𝟐 𝟎
∞
𝒆𝒙𝒑(
−𝒓 𝟐
𝟐𝝈 𝟐)
....(6)

11. Thin film composite membrane TFC comprises a fabric, a polysulfone film, and an ultra thin
salt rejecting barrier coating. A further protective coating on top of the barrier layer is also
desirable. The membrane is prepared in successive steps of
(i) solution casting of polysulfone on the fabric,
(ii) Interfacial in situ polymerization of the polyamide barrier layer on the polysulfone
(iii) Introduction of the protective layer.
(iv) Raw material :
* Non-woven polyester fabric as a base material.
* Polymers such as polysulfone, polyether sulfone(Doping solution).
* Solvents such as dimethyl formamide, dimethylsulfoxide, n-hexane, n-heptane.
* Diamines such as metaphenylene diamine.
* Acid chlorides such as trimesoly chloride, isophthaloyl chloride etc.
Preparation of Reverse osmosis membrane

13. Diagramatic description of TFC Membrane formation

14. 1. RO membrane play a crucial role in water purification and industrial applications .
2. A small contribution was made in this thesis by way of deriving a probability equation
that will be useful for simulating the growth of the active layer during interfacial
polymerization.
3. Industrial exposure was achieved while visiting UNIQFLUX Membrane Ltd.
Pune.
Conclusion

15. THANK YOU