1. Nanofilteration
Seminar And Technical Writing (CR798)
(Autumm 2021)
Course Instructor- Prof. Debasish Sarkar
Presented by :
Monika Singh
(519CR1002)
Department of Ceramic Engineering,
National Institute of Technology, Rourkela, Odisha
2. OUTLINE OF PRESENTATION
Introduction
Principal of Nanofiltration Process
What is Nanofiltration?
About Membrane Filter
Types of Membranes used in Nanofiltration
Application of nanofiltration
Advantages
Disadvantages
References
3. Water pollution is the contamination of water bodies (e.g.
lakes, rivers, oceans, aquifers and groundwater). This form
of environmental degradation occurs when pollutants are
directly or indirectly discharged into water bodies without
adequate treatment to remove harmful compounds.
Nanofiltration is one of a group of similar membrane
processes (including reverse osmosis, Ultrafiltration , and
microfiltration) 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.
Introduction
8. Principal of nanofiltration process.
Permeate post-
treatment
Retentate and
cleaning solution
treatment
Feed water pre-
treatment
NF Process
Membrane cleaning
system
Raw water
Discharge
Distribution
9. Nanofiltration
NF membranes are pressure-driven membranes with properties between those of reverse osmosis and
ultrafiltration membranes and have pore sizes between 0.2 and 4 nm.
Nanofiltration membranes (NF membranes) are used in water treatment for drinking water production or
wastewater treatment.
They are used for softening of groundwater (reduction in water hardness), for removal of dissolved
organic matter and trace pollutants from surface water, for wastewater treatment (removal of organic and
inorganic pollutants and organic carbon) and for pretreatment in seawater desalination.
10. Increasing demand of good quality water due to increasing population.
Reducing the wastage and to increase reuse of water.
Better reliability and durability of filter membranes.
To reduce the overall cost of operation.
NEED FOR Nanofiltration
11. The membrane filtration technique utilizes quite thin material having maximum size of pores and those
particles holding effect which occurs almost on entire surface area.
The advantage offered by membrane is of consisting well-defined and more effective pore size, whose
integrity can be tested in much easier way than that of depth filters, and is capable of achieving much
and much filtration of even the smallest particle.
Nanofiltration is a process which uses membrane filtration –based technique. This technique utilizes
nano-sized through-pores of cylindrical shape which can pass via membrane at 90.
Nanofiltration membranes consists of pores having size range between 1-10 nm. Membranes utilized in
this process are mainly formed from polymer thin films.
Most commonly used materials are PET (polyethylene teraphthalate) or metallic elements like
aluminum.
Membrane Filter
13. Types of Membranes Used In Nanofiltration
Depending on its construction method, membrane types are mainly classified into:
Hollow fiber membrane
Tubular membrane
Capillary membrane
Flat sheet membrane; and
Spiral wound type membrane
For Nanofiltration , spiral wound type membranes are the most commonly used style of
module.
14. Available in a range of standard diameters (2.5”,
4” and 8”) to fit standard pressure that can hold
several modules in series connected by O-rings.
The module uses flat sheets wrapped around a
central tube.
The membranes are glued along three edges over
a permeate spacer to form ‘leaves.
The permeate spacer supports the membrane and
conducts the permeate to the central permeate
tube.
Between each leaf, a mesh like feed spacer is
inserted.
Spiral wound type
15.
16. The NF separation mechanism can be identified as a sum of convection and diffusion transport
mechanisms, Convective transport of ions with the water flux through the membrane is caused by
the pressure difference between feed and permeate sides.
Diffusive transport is a consequence of the concentration gradient as achieved by the rejection of
solutes Electro-migration is caused by a “streaming potential” difference across the membrane.
Streaming potential is caused by the electric current generated by the convective flow of a fluid
that is necessarily charged through the pores of a charged membrane.
For uncharged molecules, sieving or size exclusion is primarily responsible for separation and is
controlled by molecular size in solute form.
The Nanofilteration separation mechanism
18. Micro-pollutants like herbicides and insecticides, as well as low-molecular components like colorants
and sugars can be very successfully blocked using a Nano-filtration membrane.
NF can be implemented for removing the following parameters (removal yield indicated in brackets):
Dissolved matter can be removed up to 75%.
Harmful micro-organisms can be removed like- bacteria, protozoa, algae, fungi up to more than
90%.
Removal of persistent organic matter up to 75%.
Removal of Organic compounds is feasible up to 50-90%.
Nutrients can also be removed (incl. phosphates).
Removal of Metals up to 50-90%.
Inorganic salts like sulphates can also be removed.
Effectiveness of NF
19. Food sector.
Dairy business.
Edible oil processing area.
Production of petroleum.
Manufacturing of medicines.
Pulp and Paper manufacturing.
Management of water and removal of multivalent, viruses, bacteria and suspended solids.
Desalination of water.
Water softening.
Demineralisation.
Application of nanofiltration
20. Water Treatment Using Nanofilteration
Surface water intake Coagulation, floatation and
sand filteration
Pre-Filteration
Ozonation
Distribution
Disinfection Nanofilteration
21. Seawater Desalination using Nanofiltration Method
Seawater filtered to remove suspended solids.
Stage 1: Filtered seawater pumped under high
pressure through nanofiltration membrane.
Only smallest 12% of salt molecules pass
through.
Stage 2: Water from Stage 1 is pumped under
lower pressure through second nanofiltration
Membrane.
Blocks passage of almost all remaining salts.
High quality potable water produced.
22. NF possess lesser discharge volumes, minor retentate concentrations than that of Reverse
Osmosis for minute value salts.
It reduces the content of salt and also reduces dissolved matter content i.e., (TDS) within
brackish water.
This process is chemical-free so doesn’t needs salt or chemicals while operating.
After nanofiltration, the pH of water remains usually non-aggressive.
Advantages
23. Nanofiltration consumes higher than that of Ultrafiltration and Microfiltration (0.3 to 1
kWh/m³).
Only partial removal of univalent ions and salts is possible though.
NF Membranes are quite subtle to free chlorine (its average life-time is of 1000 ppmh).
Disadvantages
24. references
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Wijmans JG, Baker RW, The solution-diffusion model: a review - Menlo Park; 1995.
Lau Kok Keong-Doctor of Philosophy, Feed spacer of spiral wound membrane module for NF and RO: modeling, simulation and design; 2007.
Zhao Yu. Modeling of membrane solute mass transfer in NF/RO membrane systems. PhD in the Department of Civil and Environmental Engineering in the College of Engineering and
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