Man is completely dependent on water.Hence pure water is essential for many purposes.Though till now many filtration techniques have been introduced so far, using of nano technology make as the purest form of water. Nanofiltration is a relatively recent membrane filtration process used most often with low total dissolved solids water such as surface water and fresh groundwater, with the purpose of softening ( polyvalent cation removal) and removal of disinfection by-product precursors such as natural organic matter and synthetic organic matter. Though this paper concentrates on function of nanofiltration,it also elaborates the applications,needs and dis advantages of it.

1. KSRM COL LEGE OF
ENGINEERING
M.AQEEL AHAMAD

2. CONTENTS
INTRODUCTION OF FILTRATION
NEED FOR FILTRATION
PROCESSES OF FILTRATION
COMPARISION OF VARIOUS PROCESSES
OF FILTRATION
BENEFITS OF NANO FILTRATION
DISADVANTAGES OF NANOFILTRATION
HOW TO OVERCOME THE DEMERITS OF
NANO FILTRATION

3. MEMBRANE PROCESSES
Generally, there are
four types of
membrane processes,
 Microfiltration.
 Ultrafiltration.
 Nanofiltration.
 Reverse Osmosis.

4. Applications of Micro- and Ultrafiltration:
 Conventional water treatment (replace all
processes except disinfection).
 Pretreat water for R.O and nanofiltration.
 Iron/Manganese removal (after oxidation).
Applications of R.O. and nanofiltration:
 R.O. application mostly desalination.
 Nanofiltration first developed to remove
hardness.
 Nanofltration can also be used to remove
pesticides.

5. HISTORY OF NANOFILTRATION
 During 1970s RO membranes with greater operating
pressures was developed.
 This resulted in considerable increase in energy cost.
 Thus, low-pressure RO membranes were developed
and came to be known as NF membranes.
 By the second half of 1980s,NF became established.
 Starting in early 1990s, it had became common and
various applications were found out.

6. NEED FOR NANOFILTRATION
Increasing demand of good quality water
due to increasing population.
Reducing the wastage and reuse of water.
Better reliability and durability of filter
membranes.
To reduce the overall cost of operation.

7. Materials used in NF membranes
• Different polymers used are polyethersulfone,
polysulfone, polyphenylsulfone,
polytetrafluoroethylene, polyvinylidene fluoride,
polyacrylonitriles, nylon, polypropylene, cellulose
acetate (CA), regenerated cellulose, and composites.
• Ceramic and cintered metals.
• carbon nanotubes.

8. Two types of membranes:
i. Spiral membranes
ii. Tubular membranes
But surface area of spiral membranes is greater than
that of tubular membranes and hence greater
capacity.

9. SPIRAL
MEMBRANE
: Cheapest,
more
sensitive to
pollution.

10. TUBULAR
MEMBRANE
Not easily
polluted

11. Benefits of Nanofiltration
Low cost of operation.
Low energy cost.
Lower discharge and less waste water than typical
Reverse Osmosis system.
Reduction of Heavy Metals (removes 95%).
Reduction of water hardness.
Reduction / Removal of viruses, bacteria and
Pesticides.

12. Reduction of Nitrates and Sulphides.
Reduction of the salt content (brackish water).
Chemical - Free filtration (No use of salt).
pH of the water can be altered for better health.
Ideal for municipal water supply, well water, river
and rain water.
Removes Iron, Lime and other problem causing
chemicals often neglected by water softeners.

13. Distinct properties of Nanofiltration
The pore size of a NF membrane corresponds to a
molecular weight cut-off of 300-500g/mol. Hence,
separation of these components from higher
molecular weight components can be achieved.
Nanofiltration membranes have a slightly charged
surface. The dimensions of pores are close to
dimensions of ions and hence charge interaction takes
place. It can be used to separate ions with different
valences.

14. Various Applications:
1. Industrial applications:
• Food and dairy sector.
• edible oil processing sector.
• Petroleum industry.
• Drug industry.
• Paper pulp industry
2. Water treatment.
3. Desalination of water.
4. Water softening.

15. Drawbacks of the process of Nanofiltration:
1. Membrane fouling.
2. Insufficient separation.
3. Treatment of concentrates.
4. Membrane lifetime and chemical resistance.
5. Insufficient rejection for individual components.

16. There are various ways to reduce the fouling
such as:
Periodic pulsing of feed.
Periodic pulsing filtrate (backwashing).
Increasing shear by rotating membrane.
Vibrating membrane.

17. Pretreatment.
Pretreatment of feed water greatly influences the
performance of NF installations.
The application of a pre-treatment has several
benefits:
 Membranes have a longer life-span when pre-treatment
i performed.
 The production time of the installation is
extended.
 The management tasks become simpler.
 The employment costs are lower.

18. SINCE PURIFIED WATER IS NECESSARY TO
EVERY ONE,NOW OR THEN THE WORLD
SHOULD BE DEPENDENT ON NANO
TECHNOLOGY.THUS IT IS EVIDENT THAT
NANOFILTRATION WILL PLAY A VITAL ROLE IN
PROVIDING A QUALITY,USABLE FORM OF
WATER IN THE FUTURE.