Plenty of fresh water resources are still inaccessible for human use. Calamities such as pollution, climate change, and global warming pose serious threats to the fresh water system. Although many naturally and synthetically grown materials have been taken up to resolve these issues, there is still plenty of room for enhancements in technology and material perspectives to maximize resources and to minimize harm. Considering the challenges related to the purification of water, materials in the form of nanofiber membranes and nanomaterials have made tremendous contributions to water purification. Nanofiber membranes made of synthetic polymer nanofibers, ceramic membranes etc., metal oxides in various morphologies, and carbonaceous materials were explored in relation to waste removal from water. Membranes for membrane adsorption (MA) have the dual function of membrane filtration and adsorption to be very effective to remove trace amounts of pollutants such as cationic heavy metals, anionic phosphates and nitrates. In addition, recent progresses in the development of advanced adsorbents such as nanoparticles are summarized, since they are potentially useful as fillers in the host membrane to enhance its performance.

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NANOFIBERS CONTROLLING HEAVY METAL
CONTAMINATION
A Seminar Report
Submitted
in Partial Fulfilment of the Requirements
for the Degree of
Master of Technology (M.Tech)
in
ENVIRONMENTAL SCIENCE & ENGINEERING
by
Vigyan Nidhi
(180206015)
Under the Supervision of
Dr. Pradeep Kumar
Professor and Head
HARCOURT BUTLER TECHNICAL UNIVERSITY
UTTAR PRADESH, KANPUR
DECEMBER, 2019

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CERTIFICATE
This is to certify that the study which is being presented in the seminar report titled
“NANOFIBERS CONTROLLING HEAVY METAL CONTAMINATION” in partial
fulfilment of the requirements for the award of the degree of Masters of Technology in Civil
Engineering and submitted to the Department of Civil Engineering, Harcourt Butler Technical
University, Kanpur is an authentic record of work carried out by Vigyan Nidhi (180206015)
during a period from July 2019 to December 2019 under the supervision of Dr. Pradeep Kumar,
Department of Civil Engineering, Harcourt Butler Technical University, Kanpur.
Dr. Pradeep Kumar
Professor & Head
Department of Civil Engineering
HBTU Kanpur
Signature:……………..
Date:…………………
Place ……………………

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ABSTRACT
Plenty of fresh water resources are still inaccessible for human use. Calamities such as
pollution, climate change, and global warming pose serious threats to the fresh water system.
Although many naturally and synthetically grown materials have been taken up to resolve
these issues, there is still plenty of room for enhancements in technology and material
perspectives to maximize resources and to minimize harm. Considering the challenges related
to the purification of water, materials in the form of nanofiber membranes and nanomaterials
have made tremendous contributions to water purification. Nanofiber membranes made of
synthetic polymer nanofibers, ceramic membranes etc., metal oxides in various
morphologies, and carbonaceous materials were explored in relation to waste removal from
water. Membranes for membrane adsorption (MA) have the dual function of membrane
filtration and adsorption to be very effective to remove trace amounts of pollutants such as
cationic heavy metals, anionic phosphates and nitrates. In addition, recent progresses in the
development of advanced adsorbents such as nanoparticles are summarized, since they are
potentially useful as fillers in the host membrane to enhance its performance.

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ACKNOWLEDGEMENT
Every project big or small is successful largely due to the effort of a number of
wonderful people who have always given their valuable advice or lent a helping
hand. I sincerely appreciate the inspiration; support and guidance of all those people
who have been instrumental in making this seminar a success.
It is my radiant sentiment to place on record my best regards, deepest sense of
gratitude to Prof. Pradeep Kumar, Head of the Department Civil Engineering,
Harcourt Butler Technical University, Kanpur for his precious guidance which was
extremely valuable for my study both theoretically and practically.
Many thanks go to the Seminar guide, Prof. Pradeep kumar, who has given his full
effort in guiding in achieving the goal as well as his encouragement to maintain our
progress in track. I would like to appreciate the guidance given by other supervisor as
well as the panels especially in our project presentation that has improved our
presentation skills by their comments and tips.
Signature of the candidate

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Contents
1. Introduction .......................................................................................................................... 1
2. Nanofibers ............................................................................................................................ 2
2.1 Electrospinning mechanism of Nanofibers…………………………………………...3
3. Heavy metal adsorption on membrane surface………………………………………………........5
3.1. The principle of membrane adsorbent.............................................................................. 7
3.2. Polymeric membranes for membrane adsorption. .............................................................. 9
3.3. Nanosized metal oxides (NMOs)/nanomaterial embedded in nanofiber to treat water. ....... 10
4. Future work and Challenges................................................................................................. 11
5. Conclusion.......................................................................................................................... 12
6. Regulationsinmanufacturing……………………………………………………………………………………...............13
7. References......................................................................................................................... .14

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List of Tables
Table 1.1: The MCL standards for the most hazardous heavy metals.....................................01
Table 3.1: Removal of heavy metals obtained by Nanofibers and by adsorption ...................06
Table 3.2.1: Electrospun Nanofiber as contaminant removal. .................................................09
List of Graph
Graph 3.1: Specific surface area and maximum adsorption capacity for acid indigo blue of
various sample of Nanofiber....................................................................................................06
List of Figures
Figure 2.1: Scale of Sizes.........................................................................................................02
Figure 2.2: Electron microscopic Image of Electrospun Nanofiber. .......................................03
Figure 2.1.1: Electrospinning Setup ………………………………………………………....03
Figure 2.1.2: The three stage deformation of the polyvinylpyrrolidone droplet under the
influence of increasing electric field……………………………………….…..…………….04
Figure 2.1.3: Schematic depicting setup and phenomenon of electrospinning ……………...04
Figure 3.1: Diameter of fiber vs Surface area by volume ratio. ………………………………………07
Figure 3.1.1: The principle of membrane adsorbent ………………………………………………….08
Figure 3.3.1: Adsorption of As(III) on the surface of composite Nanofiber……………………….....10
Figure 3.3.2: The uptake mechanism of Pb(II) from water by a nanofiber…………………...………11

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1. INTRODUCTION
Water pollution due to organic contaminants is a serious issue because of acute toxicities and
carcinogenic nature of the pollutants. The maximum contaminant level (MCL) standards, for
those heavy metals, established by United States Environmental Protection Agency
(USEPA).
Heavy
metal
Toxicities MCL
(mg/L)
Arsenic Skin manifestations, visceral cancers, vascular disease. 0.050
Cadmium Kidney damage, renal disorder, human carcinogen 0.01
Chromium Headache, diarrhea, nausea, vomiting, carcinogenic 0.05
Copper Liver damage, Wilson disease, insomnia 0.25
Nickel Dermatitis, nausea, chronic asthma, coughing, human
carcinogen
0.20
Zinc Depression, lethargy, neurological signs and increased thirst 0.80
Lead Damage the fetal brain, diseases of the kidneys, circulatory
system, and nervous system
0.006
Mercury Rheumatoid arthritis, and diseases of the kidneys, circulatory
system, and nervous system
0.00003
Table 1.1: The MCL standards for the most hazardous heavy metals (Babel and
Kurniawa 2003)
Adsorption process being very simple, economical, effective and versatile has become the
most preferred methods for removal of toxic contaminants from wastewater.
Comparatively, the adsorption process seems to be a significant technique due to its wide
applications, such as ease of operation, economic feasibility, wide availability and
simplicity of design. The adsorbents may be of mineral, organic or biological origin:
activated carbons, zeolites, clay, silica beads, low-cost adsorbents (industrial by-products,
agricultural wastes, bio-mass) and polymeric materials.
Electrospinning technique uses interactions between fluid dynamics, electrically charged
surfaces and electrically charged liquids for fabricating nanofibers for adsorption of
contaminants. Typically, electrospinning apparatus comprises a high voltage power
supply, a syringe needle connected to power supply, and a counter-electrode collector. In
electrospinning process, a strong electrical field is used to draw a polymer solution into
fine filaments. When a sufficiently high electric voltage is applied to the polymer
solution, the droplets that are ejected from the tip have an electrostatic repulsion force
that counteracts the effect of surface tension, allowing the droplets to be stretched out to
form nanofibers. The erupted and stretched filaments are travels through the air, the
solvent evaporates leaving behind a polymer fibers to be collected on an electrically
grounded collector. Many researchers came out with Nanofibers to treat water, mainly
fabricated by electrospinning, have exhibited great potential for many emerging
environmental applications.

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They can be considered as one of the safest nanomaterials due to their extremely long
length, higher permeability and surface with volume ratio and lesser diameter adjustable
functionality are also much more effective in particulate separation and liquid filtration.
2. Nanofibers
Nanofibers are fibers with diameters in the nanometer range. Here prefix “nano” was
derived from the Greek word, naˆnos, which means dwarf. One of the prefix earliest uses
in the scientific literature was in the term nanometer (nm), which was approved as a
measurement standard with a multiplying factor of 10-9, in the International Systems of
Units in 1960.(Thompson and Taylor, 2008).
Figure 2.1. : Scale of Sizes (Baalousha et al., 2014).
Nanofibers can be generated from different polymers and hence have different physical
properties and application potentials. Examples of natural polymers include collagen,
cellulose, silk fibroin, keratin, gelatin and polysaccharides such as chitosan and alginate.
Examples of synthetic polymers include poly (lactic acid) (PLA), polycaprolactone
(PCL), polyurethane (PU), poly(lactic-co-glycolic acid) (PLGA),
poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and poly(ethylene-co-
vinylacetate) (PEVA). Polymer chains are connected via covalent bonds. The diameters
of nanofibers depend on the type of polymer used and the method of production. The
diameters of nanofibers depend on the type of polymer used and the method of
production. All polymer nanofibers are unique for their large surface area-to-volume
ratio, high porosity, appreciable mechanical strength, and flexibility in functionalization
compared to their microfiber counterparts.

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Figure 2.2: Electron microscopic Image of Electrospun Nanofiber (C. Kim et.al,
2007).
2.1 Electrospinning mechanism of Nanofibers.
Nanofiber is mostly generated via Electrospinning that is a voltage-driven process where
fibers and particles are made from a polymer solution.
The most basic set up for this technique involves a solution contains:
• Reservoir (typically a syringe) and tipped with a blunt needle (for needle-based
electrospraying),
• A high voltage power source and
• A collector.
Figure 2.1.1: Electrospinning Setup. (Nooshin Nikmaram et al., 2017, International
Journal of Royal Society of Chemistry).
The electrospinning process begins when electric charges move into the polymer solution
via the metallic needle. This causes instability within the polymer solution as a result of
the induction of charges on the polymer droplet. At the same time, the reciprocal
repulsion of charges produces a force that opposes the surface tension, and ultimately the
polymer solution flows in the direction of the electric field.
A further increase in the electric field causes the spherical droplet to deform and assume a
conical shape. At this stage, ultrafine nanofibers emerge from the conical polymer droplet

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(Taylor cone), which are collected on the metallic collector kept at an optimized distance.
A stable charge jet can be formed only when the polymer solution has sufficient cohesive
force. During the process, the internal and external charge forces cause the whipping of
the liquid jet in the direction of the collector. This whipping motion allows the polymer
chains within the solution to stretch and slide past each other, which results in the
creation of fibers with diameters small enough to be called nanofibers (Bae et al., 2013;
Haider et al., 2013).
Figure 2.1.2: The three stage deformation of the polyvinylpyrrolidone droplet under
the influence of increasing electric field (Haider et al., 2013)
 The above Image showing the three stage of deformation of a polymer
(Polyvinylpyrrolidone) under influence of increasing electric field.
 The application of High Voltage to the polymeric solution held by the surface tension
creates a charge on surface of liquid.
 The electrostatic repulsion of Charges Causes a force directly opposite to the surface
tension and thus hemispherical drop formed the tip of the needle gets converted into
conical shape and further drawn into fibres.
Figure2.1.3: Schematic depicting electrospinning setup and phenomenon of
electrospinning, Haidar et al, 2015, Arabian Journal of chemistry.

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3. Heavy metal adsorption on membrane surface.
Membrane separation has been increasingly used recently for the treatment of inorganic
effluent due to its convenient operation. Membrane adsorbent technology is a membrane
integration technology that was developed in the mid-1980s (Avramescu et al. 2003, 2008).
Adsorption is a mass transfer process by which a substance is transferred from the liquid
phase to the surface of a solid, and becomes bound by physical and/or chemical interactions.
The heavy metal ions in the aqueous solution can be captured by the adsorbent though the
physical or chemical adsorption. Generally, chemical adsorption is more popular for heavy
metal removal because it has stronger interactions and higher adsorption capacity towards
heavy metals. Nanofiber membranes has a large surface area per unit mass that increases the
adsorption of contaminants.
Figure 3.1: Diameter of fiber vs Surface area by volume ratio. (Philip Gibson and Heidi
Schreuder- Gibson, U.S Army Soldier Systems Center, Natick).

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More the Diameter means more adsorption on nanofibers.
Graph 3.1 : Specific surface area and maximum adsorption capacity for acid indigo
blue of various sample of Nanofiber. W. Guan, et al., (2019) European Polymer
Journal.
The special functional groups on the surface of the adsorbents provide significant interactions
with heavy metals, resulting in the adsorptive separation of heavy metals from water.
Material/membrane Heavy
metals
Removed by NF
membrane (%)
Removed by
adsorbent
Montmorillonite, kaolin,
tobermorite, magnetite,
silica gel and alumina
Cd(II) 97% (C0 = 500 ppm) 80% from a solution
of initial
concentration
range 1–100 ppm
Chitosan coated magnetic
nanoparticles modified
with α-ketoglutaric acid
Cu(II) 99.9% (C0 = 12,000
ppm)
>95% from a
solution of initial
concentration
200 ppm
Polymeric cation exchanger
containing nano-
Zr(HPO3-S)2
Pb(II) 84% (C0 = 0.64 ppm) 98% with initial
concentration 80 ppm
Acid modified carbon As(V) 93% As(V) and 89%
As(III)
(C0 = 600 ppm)
~ 80% with initial
concentration 200
ppm
Polonite Mn(II) 98% (C0 = 310 ppm) 98.7% with initial
concentration
0.01 ± 0.031 ppm
C0 : Initial Concentration
Table 3.1. Removal of heavy metals obtained by Nanofibers and by adsorption. ( K. C.
Khulbe and T. Matsuura 2018, Removal of heavy metals and pollutants by membrane
adsorption techniques).

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Adsorption is a very significantly economic, convenient and easy operation technique. It
shows high metal removal efficiency and is applied as a quick method for all types of
wastewater treatments. It is becoming a popular technique, because in this process the
adsorbent can be reused and metal recovery is possible.
Thus, there are two types of adsorption:
1. Chemical adsorption: It is also referred to as activated adsorption: the adsorbate can form
a monolayer. It is also utilized in catalytic operations. In general, the main steps involved in
adsorption of pollutants on solid adsorbent are:
(a) Transport of the pollutant from bulk solution to external surface of the adsorbent.
Internal mass transfer is carried by pore diffusion from outer surface of adsorbent to
the inner surface of porous structure.
(b) Adsorption of adsorbate on the active sites of the pores of adsorbent. The overall
rate of adsorption is decided by either film formation or intra-particle diffusion or
both as the last step of adsorption are rapid as compared to the remaining two steps.
2. Physical adsorption: It is a general incident and occurs in any solid/liquid or solid/gas
system. Physical adsorption is a process in which binding of adsorbate on the adsorbent
surface is caused by van der Waals forces of attraction.
It is well known that pH is an important parameter for adsorption of metal ions from aqueous
solution because it affects the solubility of the metal ions in water, concentration of the
counter ions on the functional groups of the adsorbent and the degree of ionization of the of
the adsorbate during reaction.
3.1 The principle of membrane adsorbent.
A membrane adsorbent is made by connecting functional groups to the surface and pore wall
of polymer membranes; the target pollutants are selectively adsorbed to the functional group.
The membrane adsorbent effectively combines the filtration performance of the membrane.
When the contaminated water flows through the membrane, the functional active binding
sites will combine with the target pollutants to remove contaminants from drinking water
with a high adsorption rate and capacity because of the very short contact distance at a
submicron-scale level between the target pollutants to the adsorbed active binding site of the
membrane adsorbents.

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Figure 3.1.1:The principle ofmembrane adsorbent, (Zheng et al. 2014).
Currently, adsorption is regarded as the most favourable method for water cleansing, but
common adsorbents, including activated carbon, zeolites and natural fibers, suffer from low
adsorption capacities, poor selective sorption and unsatisfactory regeneration ability. A
number of advanced adsorbents, including nanostructured metal oxides, carbon nanotubes,
porous boron nitride nanosheets and porous graphene, among others, have been developed to
overcome these shortcomings.
It is well known that activated carbons possess a large surface area with different surface
functional groups, including carboxyl, carbonyl, phenol, quinone, lactone and other groups
bound to the edges of the graphite-like layers. They are therefore regarded as good adsorbents
for the removal of heavy metal ions and other inorganic substances. Bobade and Eshtiag
(2015) wrote a review entitled ‘Heavy metals removal from wastewater by adsorption
process’ which was focused on the heavy metals removal based on the performance of
various adsorbents such as natural materials, industrial byproduct, agricultural and biological
waste, biopolymers and hydrogels.
3.2. Polymeric membranes for membrane adsorption.
Traditional polymeric adsorbents were first developed in the 1960s (Kunin 1976). In membrane
adsorption, contaminants are adsorbed to the functional groups of the membrane or to the sorbent
incorporated in the support membrane while the waste water permeates through the membrane. Many
synthesized polymers or biopolymers with special functional groups (e.g., amine, carboxyl, and
sulfonic acid) also show efficient adsorption capacity for heavy metal ions (Vieira and Beppu 2005;
Saber-Samandari and Gazi 2013). Those functional groups play a dominant role in the adsorptive

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removal of heavy metals, regenerated after the adsorbents are saturated by removing the adsorbed
contaminants.
Different heavy metal ions especially Cr(VI), Zn(II), and Pb(II) can be removed from wastewater
by conducting polymer-based adsorbents. Polypyrrole (PPy) based adsorbents play a major role
for the removal of various heavy metal ions due to their ease of synthesis, biocompatibility and
redox properties. Padmavathi et al. (2014) from the four different waste water industries such as:
1. Fertilizer,
2. Sewage,
3. Tannery,
4. Dye industry.
Two different anion exchange polymers, i.e. quaternized polysulfone (QPSF) and poly styrene
ethylene butylene poly styrene (QPSEBS) membranes were used as adsorbents and the adsorption
study was done by batch adsorption process. Influence of contact time on adsorption process was
evaluated. Before and after the adsorption process, the membranes were characterized using
scanning electron microscopy (SEM). The concentration of the metal ions after adsorption
process was determined by inductively coupled plasma optical emission spectroscopy (ICP-OES).
The tannery water showed more Cr6+ content and was removed by the adsorbents efficiently up
to 30% using QPSF membranes.
Low-density polyethylene (LDPE) films were grafted by styrene/acrylic acid and by
styrene/acrylamide using gamma-radiation to obtain membranes were used in the removal of the
different heavy metals pollutants: such as (U, Zr, V and Mo) from wastewater (Dessouki et al.
2000). Hybrid membranes comprising inorganic fillers in a polymeric matrix are common. The
fillers can be used for separation improvement. Amin et al. (2014) discussed the possible
applications of the nanoparticles/fibers for the removal of pollutants from water/wastewater. The
most promising nanomaterials and applications are highlighted in given table 3.3.1 below:
Electrospun
nanofiber/membrane
Removal of From References
CA/(PMAA) Cu2+, Hg2+
and Cd2+
Water Tian et al. (2011)
PVA-Chitosan Pb, Cd Wastewater Karim (2015)
Chitosan/Al2O3/Fe3O4 Nitrate and copper Aqueous solution Bozorgpour et al.
(2016)
PAN/PET/containing
infused ultra-fine
functional
cellulose nanofibers
Escherichia coli,
Cr(VI), Pb(II)
Metal ion solutions Wang et al. (2013)
Chitosan/PVA/zeolite Cr(VI), Fe(III), and
Ni(II) ions
Potassium
dichromate, nickel,
chloride
Habiba et al. (2017)
PVA and PVA-Co-MOF Pb(II) Aqueous solution Shooto et al. (2016)
Poly(vinyl alcohol)/SiO2 Cu(II) Wastewater Wu et al. (2010)
Table 3.2.1: Electrospun Nanofiber as contaminant removal.

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3.3 Nanosized metal oxides (NMOs)/nanomaterial embedded in nanofiber to treat
water.
Due to the high surface area of nanosized metal oxides (NMOs), including nanosized ferric
oxides, manganese, Due to the high surface area of nanosized metal oxides (NMOs), including
nanosized ferric oxides, manganese oxides, aluminum oxides titanium oxides, magnesium oxides
and cerium oxides, have specific affinity for heavy metal removal via adsorption from aqueous
systems (Hua et al. 2012). Kim and der Bruggen (2010) discussed the role of engineered
nanomaterials (titania, alumina, silica, silver and many others) in (pressure driven) membrane
technology for water treatment to be applied in drinking water production and wastewater
recycling. Adsorption of adsorbate on the active sites of the pores of adsorbent. The
overall rate of adsorption is decided by either film formation or intra-particle diffusion
and some of Metal oxides are embedded with polymers to treat water because of molecular
structure.
Figure3.3.1: Adsorption ofAs(III) on the surface ofcomposite Nanofiber, (Han et al., 2011).

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Figure3.3.2: The uptake mechanism ofPb(II) from water by a nanofiber (Zare et al., 2016)
4. Future work and Challenges:
A number of advanced adsorbents, including nanostructure metal oxides, carbon nanotubes,
porous boron nitride nanosheets and porous graphene have been developed recently to
enhance adsorption capacity, selectivity and regeneration ability. These nanostructured
adsorbents have attracted much attention as one of nanotechnology applications.
However, nanoparticles cannot be packed in a column due to the high pressure drop they
cause. Hence, nanoparticles have to be either embedded in or coated on the surface of larger
particles, by which the merit of nanoparticles is largely compromised. Incorporation of
nanoparticles in nanofibrous membrane can circumvent this problem due to nanofiber’s large
surface area and porosity, which, respectively, allow high adsorption and high filtration
capacity.
When embedded in nanofibers, however, adsorption efficiency of nanoparticles is
significantly diminished. A technique should be developed to attach nanoparticles to the
nanofiber surface, while preventing the leaching of nanoparticles during filtration. Another
challenge is to establish an appropriate mathematical model for MA operation. Currently, in
most MA works, adsorption isotherm and kinetics are the only parameters to characterize MA
membranes. A set of more powerful MA membrane characterization parameters should be
found to optimize the membrane defunctionalized grapheme as a nanostructured membrane
for removal of copper and mercury from aqueous solution: a molecular dynamics simulation
study.

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5. Regulations formanufacturing
To ensure that nanoscale materials are manufactured and used in a manner that protects
against human health and environmental risks, in 2009,EPA (Environmental Protection
Agency) began work on a TSCA regulation (Toxic Substances Control Act)(EPA, 2017), that
would be applicable to all nanoscale materials. It would have two components:
a) Significant New Use Rule (SNUR)
Prior to manufacturing chemicals or introducing them into commerce, manufacturers of new
chemical substances must provide more information to the Agency for review. EPA can take
action to ensure that chemicals that may or will pose an unreasonable risk to human health or
the environment are effectively controlled.
b) Information reporting rule
This rule requires companies that manufacture (including import) or process certain chemical
substances already in commerce as nanoscale materials notify EPA of certain information
including: specific chemical identity, production volume, methods of manufacture,
processing, use, exposure and release information, available health and safety data. By
collecting such data, EPA will finally be able to draw a clearer picture of the nanomaterials
for commercial and scientific use.

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6. Conclusion:
A necessity for water filtration technology, due to global pollution and population growth,
has led to an increase in attention to advanced nanomaterials that can aid in the purification of
water. This size-dependent filtration is possible via nanofibrous membranes as they contain
high porosity and this pore size is tunable through the fabrication process. Because of this
tunability in the nanofibril membrane composition and structure, they possess promising
straining abilities, such as high permeability and selectivity, as well as low fouling.
The production of nanofibers consists of various avenues such as synthetic templates,
separation by different phases, nanoparticle self-assembly, and most widespread,
electrospinning. Electrospinning is prevalent owing to its ease of use and low cost compared
to template and self-assembly processes. The capability of nanoparticles to be coated with
several ligands and control surface area/volume ratio by means of changing its shape permits
to make a design of high selective, sensitive, and specific sensors. Nanofibers are also used to
prevent the formation of pollutants or contaminants by creating an environmentally friendly
substance or material, replacing widely used toxic materials, as well as reduced
environmental impact. The nanotechnology also plays a promising and vital role in the
improvement of rapid and accurate environmental process to decrease or prevent emissions or
to convert contaminants to useful by products. Because nanofibers have unique properties
long length, higher permeability and surface with volume ratio and lesser diameter have more
potential to adsorb contaminants. Naofibers present an innovation in water and wastewater
purification by light weight, cost effective, and less energy consuming process. As the setup
to produce nanofiber is not complex that makes nanofibers accessable at every place.

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7. References:
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 Crini G (2005) Recent developments in polysaccharide-based materials used as
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