Key Concepts-wetting, Adso, Emulsions, Collods

7/23/2019 Key Concepts-wetting, Adso, Emulsions, Collods

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Course Name: CH412-INTERFACIAL SCIENCE

Key concepts in INTERFACIAL SCIENCE

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Key concepts in IS

• ettin!

• A"sorption

• Emu#sions

• Co##oi"s



ettin!

• ettin! is t&e a%i#ity o' a #i(ui" to maintain contact

)it& a so#i" sur'ace* resu#tin! 'rom intermo#ecu#ar

interactions )&en t&e t)o are %rou!&t to!et&er+

• T&e "e!ree o' )ettin! ,)etta%i#ity is "etermine" %y

a 'orce %a#ance %et )een a"&esi.e an"

co&esi.e 'orces+

• ettin! "ea#s )it& t&e t&ree p&ases o' materia#s:

!as* #i(ui"* an" so#i"+

• It is no) a center o' attention in nanotec&no#o!y an"

nanoscience stu"ies "ue to t&e a".ent o' many

nanomateria#s in t&e past t)o "eca"es

,e+!+ !rap&ene* car%on nanotu%e+

https://en.wikipedia.org/wiki/Wetting

ettin!

•ettin! is important in t&e %on"in!

or a"&erence o' t)o materia#s+ ettin! an"

t&e sur'ace 'orces t&at contro# )ettin! are

a#so responsi%#e 'or ot&er re#ate" e''ects*

inc#u"in! so-ca##e" capi##ary e''ects+

• e!ar ess o t e amount o )ett n!* t e

s&ape o' a #i(ui" "rop on a ri!i" sur'ace is

rou!&#y a truncate" sp&ere+

• T&ere are t)o types o' )ettin!: non-reacti.e

)ettin! an" acti.e )ettin!




ater "rop#et immerse" in

oi# an" restin! on a %rass

sur'ace

ater %ea"s on a 'a%ric t&at &as %een

ma"e non)ettin! %y c&emica# treatment


Inter'acia# interactions o' materia#s+ A

Interaction (uanti'ie" as contact an!#e

,see 'ormu#a+ / Interaction "escri%e"

in terms o' !oo" )ettin! ,sprea"in!*partia# ,poor )ettin!* or non)ettin!+

Contact an!#e 'or a #i(ui" "rop#et on

a so#i" sur'ace

ettin!Contact

an!#e

0e!ree o'

)ettin!

Stren!t& o':

So#i"#i(ui"

interactions

Li(ui"#i(ui"

interactions

θ = 0 Perfect

wetting strong weak

0 < θ < 90 highwettabi!ity

strong strongweak weak

90 " θ <

#$0

!ow

wettabi!ity weak strong

θ = #$0 perfect!y

non%wetting weak strong




A"sorption

•

A"sorption is the adhesion of atoms& ions& or mo!ecu!es from a gas&!i'uid& or disso!(ed so!id to a surface. )his process creates a fi!m of

the adsorbate on the surface of the adsorbent.

• )his process differs from absorption& in which a f!uid *the

absorbate+ permeates or is disso!(ed by a !i'uid or so!id

*the absorbent +.

• ,dsorption is a surface%based process whi!e absorption in(o!(es the

who!e (o!ume of the materia!.

• )he term sorption encompasses both processes& whi!e desorption is

the re(erse of it. ,dsorption is a surface phenomenon.

https://en.wikipedia.org/wiki/ ,dsorptionwww.chemgapedia.de



www.physics.siu.edu

A"sorption

•

-imi!ar to surface tension& adsorption is a conse'uenceof surface energy.

• n a bu!k materia!& a!! the bonding re'uirements *be

they ionic&co(a!ent& or meta!!ic+ of the constituent atoms of

the materia! are fi!!ed by other atoms in the materia!.

owe(er& atoms on the surface of the adsorbent are not

who!!y surrounded by other adsorbent atoms and therefore

.

• )he eact nature of the bonding depends on the detai!s of the

species in(o!(ed& but the adsorption process is genera!!y

c!assified as p&ysisorption *characteristic of weak (an der

Waa!s forces+ or c&emisorption *characteristic of co(a!ent

bonding+. t may a!so occur due to e!ectrostatic attraction.

https://en.wikipedia.org/wiki/ ,dsorption



Emu#sions

• )he word 1emu!sion1 comes from the Latin )or" for

1to mi!k1& as mi!k is an emu!sion of fat and water&

among other components.

• )wo !i'uids can form different types of emu!sions. ,s

an eamp!e& oi! and water can form& first& an oi!%in%water emu!sion& wherein the oi! is the dispersed

p ase& an wa er s e spers on me um.

• -econd& they can form a water%in%oi! emu!sion&

wherein water is the dispersed phase and oi! is the

eterna! phase.

• 2u!tip!e emu!sions are a!so possib!e& inc!uding a1water%in%oi!%in%water1 emu!sion and an 1oi!%in%

water%in%oi!1 emu!sion.https://en.wikipedia.org/wiki/3mu!sion

www.ticgums.com

www.youtube.com



Emu#sions

• ,n emu#sion is a miture of two or more !i'uids that are

norma!!y immiscib!e *unmiab!e or unb!endab!e+.

• Emu#sions are part of a more genera! c!ass of two%phase

systems of matter ca!!ed co!!oids.


Emu#sions

•

,!though the terms colloid an" emulsion aresometimes used interchangeab!y& emulsion shou!d be

used when both the "isperse" an" t&e continuous

p&ase are #i(ui"s+

• n an emu!sion& one !i'uid *the dispersed phase+

is dispersed in the other *the continuous phase+.

•

Eamp#es o' emu#sions inc!ude (inaigrettes& mi!k&mayonnaise *3gg yo!ks& oi! and (inegar+& and

some cutting f!uids for meta! working.

3gg yo!ks: t&e ye##o) sp&erica# part o' an e!! t&at is

surroun"e" %y t&e a#%umen

https://en.wikipedia.org/wiki/3mu!sion



Co##oi"s• , co##oi" is a substance in which microscopica!!y dispersed

inso!ub!e partic!es are suspended throughout another

substance. -ometimes the dispersed substance a!one is ca!!ed

the co!!oid

• the term co##oi"a# suspension refers unambiguous!y to the

o(era!! miture *a!though a narrower sense of the word

suspension is contradistinguished from co!!oids by !arger

4 .

• 5n!ike a so!ution& whose so!ute and so!(ent constitute on!y

one phase& a co!!oid has a dispersed phase *the suspended

partic!es+ and a continuous phase *the medium of

suspension+.

• )o 'ua!ify as a co!!oid& the miture must be one that doesnot sett!e or wou!d take a (ery !ong time to sett!e appreciab!y.

https://en.wikipedia.org/wiki/6o!!oid

$i#3 is an emu#si'ie" co##oi" o' #i(ui" %utter'at !#o%u#es "isperse" )it&in a )ater-%ase"

so#ution+

www.chm.bris.ac.uk

maryha!!y.wordpress.com

https://en.wikipedia.org/wiki/6o!!oid



www.scienceiscoo!.org



science.howstuffworks.com$ars&ma##o): Spon!y con'ection ma"e o' !e#atin an"

su!ar an" corn syrup an" "uste" )it& po)"ere" su!ar

$em%ranes• , mem%rane is a se!ecti(e barrier b/w two phases.

• ,t times& it is a!so an outer co(ering of ce!! or ce!!

organe!!e that a!!ows the passage of certain

constituents and retains other constituents found in

.

• )he inf!uent of a membrane is known as the feed%stream& the !i'uid that passes through the

membrane is known as the permeate and the !i'uid

containing the retained constituents is the retentate

or concentrate.



$em%ranes

• )he concept of a membrane has been known since the

eighteenth century& but was used !itt!e outside of the

!aboratory unti! the end of Wor!d War .

• 7rinking water supp!ies in 3urope had been compromised by

the war and membrane fi!ters were used to test for water

safety.

• owe(er& due to the !ack of re!iabi!ity& s!ow operation&

reduced se!ecti(ity and e!e(ated costs& membranes were not

wide!y ep!oited.

• )he first use of membranes on a !arge sca!e was with micro%

fi!tration and u!tra%fi!tration techno!ogies.

• -ince the #9$0s& these separation processes& a!ong with

e!ectrodia!ysis& are emp!oyed in !arge p!ants and& today& a

number of eperienced companies ser(e the market.

$em%ranes• )he degree of se!ecti(ity of a membrane depends on the

membrane pore si4e.

• 7epending on the pore si4e& they can be c!assified as

microfi!tration *28+& u!trafi!tration *58+& nanofi!tration *8+

and re(erse osmosis *;+ membranes.

• em ranes can a so e o (ar ous t c ness&

with homogeneous or heterogeneous structure.

• 2embranes can be neutra! or charged& and partic!e transport

can be acti(e or passi(e.

• )he !atter can be faci!itated by pressure& concentration&

chemica! or e!ectrica! gradients of the membrane process.

• 2embranes can be genera!!y c!assified into synthetic

membranes and bio!ogica! membranes



$em%rane processes an" "ri.in! 'orce

www.separationprocesses.com

www.s!ideshare.net



www.intechopen.com

$em%rane C#assi'ications

www.smartmembraneso!utions.co.n4



Types o' $em%rane Separation

an" Scope o' App#ication

www.toyobo%g!oba!.com





$em%rane /ioreactor System,Se)a!e treatment

systems



$em%rane $ateria#s-c#assi'ication

• ,!most a!! industria! membrane processes are made from natura! or

synthetic po!ymers.

• )hese membranes are sometimes known as organic membranes.

atura! po!ymers inc!ude woo!& rubber *po!yisoprene+ and ce!!u!ose.

•

3amp!es of synthetic po!ymers inc!ude po!yamide& po!ystyrene andpo!ytetraf!uoroethy!ene *)ef!on+.

• 2embranes can a!so be made from other non%po!ymeric materia!s.

-uch membranes inc!ude inorganic membranes *for eamp!e meta!&

ceramic& carbon and 4eo!ites+ and !i'uid membranes.

• n addition& recent de(e!opments had !ed to the introduction of the so%

ca!!ed ybrid 2embranes *or 2ied 2atri 2embranes& where both

organic and inorganic components are used+.

• ,nother (ariation in membranes app!ication is the ipo!ar2embranes *P2+. where membranes of different ionic charge are

1sandwiched1 together.

$em%rane mo"u#es1+ #ate-an"-'rame

2+ Tu%u#ar

5+ Spira#-)oun"

4+ Ho##o) 'i%er



•

#ate-an"-Frame $o"u#es• )he p!ate%and%frame modu!es were one of the

ear!iest types of membrane system&

• but because of their re!ati(e!y high cost they

ha(e been !arge!y rep!aced in most

%

ho!!ow%fiber modu!es.

• P!ate%and%frame modu!es are now used on!y

in e!ectrodia!ysis and per(aporation systems

and in a !imited number of re(erse osmosis

and u!trafi!tration app!ications with high!y

fou!ing conditions.



synderfi!tration.com



#ate-an"-'rame units use t&e

mem%rane itse#'* ai"e" %y #oc3 rin!s or

strips* to sea# o'' t&e 'ee" retentate

'rom miin! into t&e permeate

c&anne#s+

•

Tu%u#ar $o"u#es• )hese modu!es are now genera!!y !imited to

u!trafi!tration app!ications& for which the benefit of

resistance to membrane fou!ing outweighs the high

cost.

• )ubu!ar membranes contains as many as to > sma!!er

tu es& eac . to . cm n ameter& neste ns e a

sing!e !arger tube.

• n a typica! tubu!ar membrane system& a !arge number

of tubes are manifo!ded in series.

• )he permeate is remo(ed from each tube and sent to a

permeate co!!ection header.



Tu%u#ar mem%rane mo"u#e

www.forwardosmosistech.com

Tu%u#ar mem%rane mo"u#e

www.kochmembrane.com



cross '#o) mo"u#e

www.pa!!.com

$em%rane mo"u#e )it& mu#tip#e tu%u#ar

mem%ranes ,or mu#ti-tu%e mo"u#e

on!inembr.info



• Spira#-)oun" mo"u#es• ndustria!%sca!e modu!es contain se(era! membrane en(e!opes& each

with an area of # to ? m?& wrapped around the centra! co!!ection pipe.

• 2u!ti%en(e!ope designs minimise the pressure drop encountered by

the permeate tra(e!!ing toward the centra! pipe.

• )he standard industria! spira!%wound modu!e is $%inch in diameter and@0%inch !ong.

• .

• )he feed so!ution passes across the membrane surface& and a portion

of the feed permeates into the membrane en(e!ope& where it spira!s

towards the centre and eits through the co!!ection tube as shown in

the 8igure.

• @ to A spira!%wound membrane modu!es are norma!!y connected in

series inside a sing!e pressure (esse!.

• , typica! $%inch diameter tube containing A modu!es has #00 to ?00

m? of membrane area.

Spira# )oun" mem%rane mo"u#e

en.wikipedia.org



Ho##o)-'i%re mo"u#es

• o!!ow%fibre modu!es are characteristica!!y @%$inch *#0%?0 cm+ in diameter and B% *#.0%#.A m+

feet !ong.• o!!ow%fibre units are a!most a!ways run with the

feed stream on the outside of the fibre.

• Water passes through the membrane into theinside or 1!umen1 of the fibre.

• , number of ho!!ow%fibres are co!!ected together

and 1potted1 in an epoy resin at both ends andinsta!!ed into an outer she!!.

• n the she!!%side feed design& a !oop or c!osed bund!e of fibres iscontained in a pressure (esse!.

• )he system is pressurised from the she!! side& and the permeatepasses through the fibre wa!! and eits through the open fibreends. )his design is easy to fabricate and a!!ows (ery !argemembrane areas to be contained in an economica! system.

• ecause the fibre wa!! must support considerab!e hydrostaticpressure& the fibres usua!!y ha(e sma!! diameters and thick wa!!s&

% %

Ho##o)-'i%re mo"u#es-t)o "esins

diameter.• n the bore%side feed design& the fibres are open at both ends and

the feed is circu!ated through the bore *annu!us area+ of thefibres.

• )o minimise pressure drop inside the fibres& the diameter areusua!!y !arger than those of the fine fibres used in the she!!%sidefeed design.



Ho##o) 'i%er mem%rane mo"u#e

www.kochmembrane.com

Ho##o) 'i%er mem%rane

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Key Concepts-wetting, Adso, Emulsions, Collods