Tổng Hợp Vật Liệu Nano Composite

n tt nghip Khoa CNSH & MT

M u

Ngy nay cng ngh nano ang dn dn lm thay i cuc sng ca con

ngi. Vi kch thc nh b c nanomet, vt liu nano c nhng tnh cht v cng

c o m nhng vt liu dng khi khc khng th c c nh bn c hc

cao, hot tnh xc tc mnh, kh nng hp ph vt tri Chnh nhng tnh cht

mi ny m ra cho vt liu nano nhng ng dng v cng to ln trong nhiu lnh

vc khoa hc cng ngh v i sng, v c bit l kh nng ng dng trong cng

ngh x l mi trng, khi m tnh trng nhim mi trng ang ngy mt tr

nn trm trng ti nhiu ni trn th gii.

Bn cnh nhng nguyn nhn do cc yu t t nhin nh qu trnh ha tan

cc khong cht cc lp t , trm tch...th nguyn nhn gy ra tnh trng

nhim khng th khng k n l do cc hot ng ca con ngi. Cuc sng pht

trin ko theo s pht trin ca cc ngnh cng nghip, cc ngnh sn xut phc v

i sng to ra mt lng ln cht thi, e da nghim trng n mi trng t,

mi trng khng kh, v c bit l mi trng nc. Thm vo s bng n dn

s th gii lm cho nhu cu nc sch cho n ung ni ring v sinh hot v sn

xut ni chung trn th gii ngy cng gia tng. Rt nhiu cc quc gia ang ng

trc tnh trng thiu ht ngun nc sch, m bo cht lng cho sc kho con

ngi.

Vn nhim asen trong nc ngm c th gii nh gi l mt vn

mang tnh ton cu. c hn ba mi quc gia trn th gii c bo co v tnh

trng nhim asen trong nc ngm trong c Vit Nam. Theo nh gi ca t

chc y t th gii (WHO), trn th gii c hn 100 triu ngi s l nn nhn ca s

nhim c asen, v Vit Nam l hn 10 triu ngi. Ngoi asen ra trong nc

ngm cn c s hin din ca rt nhiu cc kim loi nng khc nh Hg, Pb, Ni, Cr,

Mn, Fe

Qun Th Thu Trang MSSV: 505303065


Vic x l asen v crm trong nc ngm ang c gii khoa hc rt quan

tm nghin cu, do c tnh v nhng nh hng nghim trng m chng c th

gy ra cho sc khe con ngi. Rt nhiu cc cng trnh nghin cu c a ra

nhm tm kim cc cng ngh v vt liu loi b cc hp cht ca asen v crm

trong nc. Trn thc t c rt nhiu vt liu c kh nng hp ph asen v crm, tuy

nhin hin nay ngi ta ch nhiu n cc vt liu xc tc hp ph c kch thc

nano do kh nng hp ph vt tri v cc tnh cht mi ca chng khi cp

nano mt.

Da trn mt s kt qu nghin cu ca cc tc gi trong v ngoi nc v

kh nng hp ph ca cc vt liu mangan dioxit v vt liu nano oxt st t: Vt

liu nano oxt st t c kh nng hp ph tt c hai dng As(III) v As(V) dung

lng hp ph cao v tc ln, cn vt liu MnO2 va c tnh nng xc tc oxy

ho mnh va c kh nng hp ph tt. C hai loi vt liu u c ch to t

ngun nguyn liu d kim, r tin v thn thin vi mi trng. Nhm mc tiu kt

hp cc c tnh qu ca hai loi vt liu ny chng ti la chn ti Tng hp

vt liu nano composite t tnh Fe3O4/MnO2. Xc nh cc c trng v hiu ng

oxy ho hp ph Asen, Crm ca vt liu.

Mc tiu ca ti l :

Xy dng quy trnh cng ngh ch to vt liu bt xp nano composite st t Fe3O4/ MnO2 trong Fe3O4 nh l li c bc bi mng MnO2 kch thc nano

bng phng php ng kt ta.

nh gi cc c trng c bn ca vt liu nano composite Fe3O4/ MnO2 ch to c.

nh gi s b kh nng hp ph crm, asen ca vt liu nhm nh hng ng dng trong cng ngh x l nc.



Chng I

tng quan ti liu

I-Asen

Asen hay cn gi l thch tn c k hiu ha hc l As ng th 33 bng h

thng tun hon Mendeleev, khi lng nguyn t bng 74.92, l nguyn t rt c

phn tn trong t nhin. Ngi ta c th pht hin ra s hin din ca asen trong tt

c cc mu t , khong vt, cc mu trm tch, trong cc mu ng thc vt,

trong nc bin, nc ngm . Trong mi trng nc asen thng tn ti dng

asen hu c v asen v c. Trong hai dng asen hu c v asen v c, ngi ta quan

tm nhiu n cc dng asen v c do

c tnh cao cng nh s hin din ph

bin ca chng trong nc ngm. Cc

dng asen tn ti ch yu trong nc

ngm bao gm H2AsO4- (trong mi

trng pH gn axt n trung tnh),

HAsO42- (trong mi trng kim). Hp cht H3AsO3 c hnh thnh ch yu trong

mi trng oxy ho - kh yu trong dng As(III) thng c hn As(V).

I.1. Asen - Him ha vi sc khe con ngi

T lu con ngi bit n s nhim c asen qua ng h hp v qua

ng tiu ha. V mt sinh hc, asen nh hng n thc vt nh l mt cht ngn

cn qu trnh trao i cht, lm gim nng sut cy trng, c bit trong mi trng

thiu phospho. i vi con ngi asen t tp trong gan, thn, hng cu c bit t

tp trong no, da, xng, phi v tc.

S nhim c asen xut hin nh mt thm ha mi trng i vi sc khe

con ngi. Cc biu hin u tin i vi nhim c asen l chng sm da, dy biu

b sng ha da, t dn n hoi th hay ung th da. Cc iu tra ti i Loan



tm thy mt lot s lin quan gia vic nhim asen vi bnh tc nghn mch mu

ngoi bin (bnh chn en - cc chi b chuyn thnh mu en do b hoi th). Asen

cn l nguyn nhn ca rt nhiu cc cn bnh nguy him khc nh ung th phi,

thn, bng quang, rut kt, mi . im c bit quan trng l c hai dng As(V)

v As(III) u l nhng cht d ha tan trong trong nc v khng mu khng v do

khng th pht hin bng trc gic c. Chnh v vy cc nh khoa hc gi

chng l St th v hnh. Mt s hnh nh nhim c asen a ra trn hnh 2.

Hnh2: (a, b) - Hnh nh nhim c asen,(a) (b)

(c) - Ngi dn s dng nc ngm nhim asen khng qua x l

Trong hn 10 nm qua cc nh khoa hc trn th gii nhn thy rng tnh

trng phi nhim asen ngy cng gia tng v tr thnh vn mang tnh ton

cu, c bit ti cc quc gia nh n , i Loan, Thi Lan, Mehico, Chile, M,

Campuchia, Vit Nam[1,2].

Vit Nam, asen c trong nc ngm c pht hin u tin nm 1993.

Sau t chc y t th gii WHO v UNICEF nhn thy cu trc a cht ca Vit

Nam c c th tng t nh Bangladesh nn khuyn co v kh nng c th c

s hin din ca asen trong nc ngm. Theo thng bo ca B ti nguyn Mi

trng: cc tnh ng bng Bc B nh H Ni, H Nam, Hng Yn, H Ty, Vnh

Phc... u c hin tng nhim asen. Khng ch ng bng Bc B, khu vc

min Trung cng c biu hin nhim vi mc khc nhau. Khu vc ng bng



sng Cu Long: mc nhim tng i nng n. Ti 4 tnh Long An, ng

Thp, An Giang, Kin Giang u nhim asen trong nc ngm. Theo nh gi ca

WHO, nc ta c trn 10 triu ngi c th phi i mt vi nguy c tim tng v

nhim c asen [2].

I.2. Cc cng ngh loi b asen trong nc:[3]

Cc cng ngh loi b asen trong nc ch yu da trn cc qu trnh sau:

Qu trnh oxi ha kh: Cc qu trnh ny khng loi b c asen trong nc

nhng gp phn lm tng thm hiu qu ca cc qu trnh sau .

Qu trnh kt ta: a asen v dng khng tan v d nh calcium arsenat.

Cht rn ny c loi b ra khi nc nh qu trnh lng v lc. Cc cht keo t

c a vo trong nc, khi thy phn chng kt ta di dng bng c kh nng

hp ph asen v c tch ra khi nc nh qu trnh lng v lc.

Qu trnh mng: S pht trin ca cc mng lc nano v mng thm thu

ngc RO c kh nng tch n 99,8% cc dng asen ha tan trong nc. y l

mt bc pht trin vt bc trong x l nc sinh hot cng nh nc tinh khit.

Tuy nhin cng ngh ny rt t, i hi phi chi ph cho mt h thng tin x l

t cht lng cao

Qu trnh hp th thc vt: C rt nhiu loi thc vt c kh nng hp th

asen trong t, nc, in hnh l loi cy dng x c coi l thc vt siu hp th

asen. Qu trnh ny rt ph hp vi vic ci to t nhim kim loi nng [4].

Qu trnh hp ph: Rt nhiu cc vt liu trn c s cc hp cht ca Al, Fe,

Mn c i lc mnh vi asen trng thi ha tan. Asen b hp ph ti cc tm hp

ph trn b mt vt liu rn. Cc nh gi u cho rng chng l vt liu c hiu

qu cao trong vic loi b asen trong nc.

Qu trnh trao i ion: L phng php hiu qu trong vic loi b cc asen

dng ha tan. y l qu trnh trao i gia cc ion trong pha rn (nha trao i

ion) v pha lng. Phng php ny tng i phc tp v t tin.



Trn c s cc qu trnh trn trn th gii hnh thnh mt s cng ngh

x l asen trong nc [5] c a ra trn hnh 3.

Hnh 3: Cc cng ngh ang c s dng loi b asen

Trong cc cng ngh ny ngoi tr cng ngh mng v cng ngh thc vt,

tt c cc cng ngh cn li ch hiu qu i vi dng As(V) v khng hiu qu i

vi As(III), do tnh an ton khng cao. Trong khi cng ngh mng l cng

ngh c th tch c trn 99,8% cc dng asen song li rt t tin v i hi phi

c mt h tin x l c cht lng thch ng. Cn cng ngh thc vt c nh

gi l cng ngh thch hp vi cc nc pht trin trong ci to t v cha thch

hp vi cc nc ngho.

II . Crm (Chromium)

Crm l mt nguyn t ha hc c k hiu Cr thuc nhm 6, chu k 4, khi

lng nguyn t 51.996, trong bng tun hon. Crm l mt kim loi cng, mt



bng, mu xm thp v nhit nng chy cao (Tnc =2.180K). Crm kim loi l

cht khng mi, khng v v d rn. Cc trng thi ph bin ca crm trong nc l

dng Cr(II), Cr(III), Cr(VI), trong dng Cr(III) l n nh nht. Cc hp cht ca

crm dng Cr(VI) l nhng cht c tnh xi ha rt mnh.

Crm c khai thc ch yu t qung cromit (FeCr2O4). Gn mt na qung

cromit trn th gii c khai thc ti Nam Phi, Kazakhstan, n v Th Nh K

[20]. Mc d cc trm tch crm t nhin (crm nguyn cht) l kh him, nhng

vn c mt vi m crm kim loi t nhin c pht hin nh m Udachnaya ti

Nga .Trong t nhin, crm tn ti ch nh l mt kim loi vt. Tuy nhin ngy

nay, lng crm ngy mt gia tng do cc hot ng sn xut ca con ngi pht

tn cc cht thi vo mi trng nh ca ca mt s ngnh: khai thc qung, luyn

kim, m crm, cng nghip thuc da, sn xut thuc nhum

II.1. nh hng ca Crm ti sc khe con ngi

Cr(III) l nguyn t vi lng rt cn thit cho qu trnh trao i cht nht l

s chuyn ho ng trong c th ngi, khi c th thiu crm c th sinh ra bnh

gi l bnh thiu ht crm. Ngc li, dng Cr(VI) li rt c hi c th gy t

bin gen. Nu c nng ln hn 0,1mg/l c th gy sc, nn ma Khi thm

nhp vo c th Cr(VI) lin kt vi cc nhm - SH trong enzim v lm mt hot tnh

ca enzim gy ra rt nhiu bnh i vi con ngi:

- Phn ln cc hp cht Cr(VI) gy kch thch mt, da v mng nhy. Khi da tip

xc trc tip vo dung dch Cr(VI), ch tip xc d b phng rp ln sau b vim

lot (c th b lot n xng). Phi nhim kinh nin trc cc hp cht crm (VI)

c th gy ra tn thng mt vnh vin, nu khng c x l ng cch. Crm

xm nhp theo ng h hp d dn ti bnh vim yt hu, vim ph qun, vim

thanh qun do nim mc b kch thch (sinh nga mi, ht hi, chy nc mi).

- Nhim c crm c th n n bnh tiu ng, ung th phi, ung th gan, lot



da, vim da, vim gan, vim thn, au rng, tiu ho km, gy ng c h thn kinh

v h tun hon . T chc y t th gii khuyn co hm lng cho php ti a

ca Cr(VI) trong nc ung l 0,05mg/l . Tiu chun nc n ung ca Vit Nam

(TCVN 5502-2003) cng quy nh hm lng crm ti a cho php l 0,05 mg/l.

II.2. Cc phng php loi b crm trong nc.

Phng php kt ta: Crm tn ti trong nc c hai dng Cr(III) v

Cr(IV). Dng Cr(IV) thng tan nhiu trong nc v khng to c kt ta

hydroxit. Do , tch loi crm ra khi nc, phi tin hnh kh Cr(VI) thnh

Cr(III), sau kt ta Cr(III) bng cc dung dch Ca(OH)2 hoc NaOH v tch loi

kt ta bng phng php lng, lc.

Trao i ion: Vic loi b crm trong nc cng c th c thc hin bng

phng php trao i ion. So vi phng php kt ta ha hc, phng php ny t

hiu qu cao, song i hi vn u t ln, k thut vn hnh nghim ngt v ch

thch hp vi cc trm x l quy m nh.

Phng php mng: Thm thu ngc v lc nano c th s dng loi b

crm vi kh nng tch n 99,8% cc dng crm trong nc. y l s pht trin

vt bc trong x l nc sinh hot cng nh nc tinh khit. Tuy nhin phng

php ny i hi phi c mt h tin s l t hiu qu cao. Do chi ph lp t v

vn hnh ln, thng xuyn phi c quan trc v bo dng, ngoi ra pH, p sut,

nhit phi tho mn cc iu kin k thut mt cch nghim ngt .

Phng php in ha: Phng php ny s dng hiu ng in di ca cc

cation trong dung dch nc: di tc dng ca in trng mt chiu c in th

thp (50 - 150V), cc ion ca cht gy nhim trong nc s di chuyn v pha

in cc mang in tch tri du. Phng php in ha rt thch hp x l crm.

Phng php sinh hc: Crm c th ly ra khi nc bng qu trnh kh sinh

hc. Mt s cc chng vi khun k kh nh chng vi khun Pseudomonas c kh

nng xc tc cc phn ng kh trc tip Cr(VI) thnh Cr(III). Qu trnh kh Cr(VI)



bng vi sinh vt c th c tin hnh bn trong thnh t bo hoc trong dung dch.

N c th l s kh trc tip Cr(VI), hoc kh mt loi kim loi khc, sau kh

crm bng kim loi b kh. Bn cnh , ngi ta cn s dng mt s loi cy

trng x l t v nc ngm nhim ha cht bng cch hp ph kim loi nng

qua thn hoc r. y l mt qu trnh bao gm cc bc hp th, tch t, tch hoc

phn hy ha sinh. Phng php sinh hc l phng php tng i r tin v rt

thn thin vi mi trng tuy nhin phng php ny c nh gi l ch ph hp

vi cc nc pht trin trong ci to t [11].

Phng php hp ph: Crm c th ly ra c khi dung dch nc bng

phng php hp ph cho c hai dng l Cr(III) v Cr(VI). Trong cc dng tn ti

trong nc th Cr(VI) c kh nng hp ph d dng hn. Do vy, tng hiu qu

ca qu trnh hp ph, ngi ta thng phi oxi ha Cr(III) ln Cr(VI).

Cc nh khoa hc chng minh rng vt liu MnO2 l vt liu c kh nng

xc tc oxy ho hp ph cao v c th s dng vt liu ny oxi ha Cr(III) thnh

Cr(VI) nhm tng hiu qu hp ph. Bn cnh , MnO2 cn c s dng rng ri

trong vic oxy ho cc hp cht hu c trong nc cng nh lm vt liu trong x

l kh thi d bay hi

III - Cng ngh nano v vt liu nano.

III.1. Cng ngh nano.

Cng ngh nano l ngnh cng ngh lin quan n vic phn tch, thit k,

ch to v ng dng cc cu trc, thit b v h thng bng vic iu khin hnh

dng, kch thc trn quy m nano mt (1nm =10-9 m).

Theo sng kin quc gia v khoa hc v cng ngh nano (National Nanotechnology

Initiative -NNI) ca M [21], cng ngh nano phi bao hm cc lnh vc sau:

Nghin cu v pht trin cng ngh cp nano vi kch thc khong t 1nm n 100nm.



To ra v s dng cc cu trc, thit b v h thng c cc c tnh v chc nng mi do kch thc rt nh ca chng.

III. 2. Vt liu nano.

III.2.1. nh ngha v phn loi vt liu nano [22].

Vt liu nano l vt liu m trong cu trc ca cc thnh phn cu to nn n

t nht phi c mt chiu kch thc nano mt.

Vt liu nano c th tn ti 3 trng thi: rn, lng, kh. Trong , vt liu

nano rn ang c quan tm nghin cu nhiu nht, sau n vt liu lng v

kh.

C th phn chia vt liu nano thnh 3 loi (dng) :

- Vt liu nano 3 chiu (cn gi l vt liu nano khng chiu) l vt liu c

c 3 chiu u c kch thc nano mt: v d nh m nano, keo nano, ht nano

- Vt liu nano hai chiu l vt liu trong c hai chiu c kch thc nano

mt: v d nh mng nano

- Vt liu nano mt chiu l vt liu ch c mt chiu duy nht c kch thc

nano mt: v d nh ng nano, dy nano

III.2.2. c im, tnh cht ca vt liu nano.

Mt c im v cng quan trng ca vt liu nano l kch thc ch cp

nano mt. Chnh v vy m tng s nguyn t phn b trn b mt vt liu nano

v tng din tch b mt ca vt liu ln hn nhiu so vi vt liu thng thng.

iu ny lm xut hin vt liu nano nhiu c tnh d thng, c bit l kh

nng xc tc hp ph. Vi kch thc nh cp phn t, vt liu nano xut hin

ba hiu ng chnh: hiu ng lng t, hiu ng b mt, hiu ng kch thc.

Hiu ng lng t [16, 22] i vi cc vt liu thng thng hnh thnh t rt nhiu nguyn t (1m3 vt liu c khong 1012 nguyn t). Cc hiu ng lng t c trung bnh ha cho



tt c cc nguyn t, v th m ta c th b qua nhng khc bit ngu nhin ca

tng nguyn t m ch xt gi tr trung bnh ca chng. Nhng i vi vt liu

nano, do kch thc ca vt liu nh, h c rt t nguyn t nn cc tnh cht lng

t th hin r hn v khng th b qua. iu ny lm xut hin vt liu nano cc

hiu ng lng t nh hiu ng ng ngm

Hiu ng b mt [16, 22]. vt liu nano, t s cc nguyn t nm trn b mt trn tng s cc nguyn

t ca vt liu ln hn nhiu so vi vt liu dng khi nn s cc tm hot ho v

din tch b mt ca vt liu cng tng ln rt nhiu so vi cc vt liu dng khi.

V th, cc hiu ng c lin quan n b mt nh: kh nng hp ph, hot ng

b mt ca vt liu nano s ln hn nhiu. iu m ra nhng ng dng mi

trong lnh vc xc tc, hp ph v nhiu hiu ng khc m cc nh khoa hc ang

quan tm nghin cu.

Hiu ng kch thc [22] Cc vt liu truyn thng thng c c trng bi mt s cc i lng vt

l, ha hc khng i nh dn in ca kim loi, nhit nng chy, nhit

si, tnh axitTuy nhin, cc i lng vt l v ha hc ny ch l bt bin nu

kch thc vt liu ln (thng l ln hn 100nm). Khi gim kch thc ca vt

liu xung n cp nano mt (nh hn 100nm), th cc i lng l, ha trn

khng cn l bt bin na, ngc li chng s thay i. Hin tng ny c gi l

hiu ng kch thc [2]. Kch thc m , vt liu bt u c s thay i cc tnh

cht c gi l kch thc ti hn. V d nh: in tr ca mt kim loi kch

thc v m m ta thy hng ngy s tun theo nh lut . Nu ta gim kch thc ca vt liu xung nh hn qung ng t do trung bnh ca in t trong kim loi

(thng l vi nano mt n vi trm nano mt) th nh lut khng cn ng na. Lc in tr ca vt liu c kch thc nano s tun theo cc quy tc lng

t.



Cc nghin cu cho thy cc tnh cht in, t, quang, ha hc ca cc vt

liu u c kch thc ti hn trong khong t 1nm n 100 nm nn vt liu nano

cc tnh cht ny u c biu hin khc thng so vi cc vt liu truyn thng.

[22]

III.2.3. Vt liu nano composite. [22]

Thut ng nano compotsite m t mt nhm vt liu compotsite pha

tng cng ch c kch thc mc nano mt. S c mt ca pha tng cng ny

to ra nhng ci tin ln v bn cht vt l v c hc ca vt liu nanocomposite.

Vt liu nano composite va kt hp c nhng tnh cht qu d thng ca vt

liu nano, va c nhng tnh cht ring ca tng cu t hp thnh. Trong vt liu

composite da vo mc tiu ch to m ngi ta s dng nhng nguyn liu khc

nhau. S c mt ca pha tng cng to ra cho sn phm nhng tnh cht m bn

thn cc thnh phn ban u khng c. Vt liu nanocomposite l mt vt liu c

nhiu ng dng trong nhiu lnh vc. Do vy nghin cu ch to vt liu nano

composite l mt hng quan trng ang c pht trin mnh m. Pha tng cng

trong vt liu nano composite thng l cc ht nano, cc ht keo nano, mng nano,

siCht mang trong vt liu nano composite thng l cc polyme, si cacbon,

cc mui, zeolit v silica, bentonite[12]

III.3 Cc phng php tng hp vt liu nano v nano composite. [17, 22]

Hai phng php c bn tng hp vt liu nano l phng php i t trn

xung (top-down) v phng php i t di ln (bottom-up). Phng php i t

trn xung l phng php to ht kch thc nano t cc ht c kch thc ln hn.

Phng php t di ln l phng php hnh thnh ht nano t cc nguyn t hoc

ion.

III.3.1 Phng php t trn xung



Phng php t trn xung l phng php dng k thut nghin v bin dng

bin vt liu c kch thc ln v kch thc nano.

Phng php nghin: Vt liu dng bt c nghin trong my nghin vi nhng vin bi c lm t cc vt liu siu cng t trong ci nghin. My nghin

c th l nghin lc, nghin rung, hoc nghin quay. Cc vin bi cng va chm vo

nhau v ph v bt n kch thc nano. Kt qu thu c l vt liu nano khng

chiu.

Phng php bin dng: Phng php bin dng c th l n thy lc, tut, cn p. Nhit c th iu chnh ty thuc vo tng trng hp c th. Nu nhit

ln hn nhit phng th gi l bin dng nng, cn nhit nh hn nhit

phng th gi l bin dng ngui. Kt qu thu c l cc ht nano mt chiu hoc

hai chiu.

Nhn chung, phng php t trn xung l phng php n gin, r tin, c

th ch to c mt lng ln vt liu. Tuy nhin, tnh ng nht ca vt liu

khng cao v kh iu khin kch thc ca vt liu do vy phng php t trn

xung t dng iu ch vt liu nano so vi phng php t di ln.

III.3.2. Phng php t di ln (bottom-up)

Ngc li phng php t trn xung, phng php t di ln hnh thnh vt

liu nano t cc thnh phn cp nguyn t hoc ion. u im ca phng php

ny l tng hp c vt liu nano kch thc nh, ng u theo mong mun.

Phn ln cc vt liu nano hin nay iu ch t phng php ny. N c th l

phng php vt l, ha hc hoc kt hp c hai phng php.

Phng php vt l: y l phng php to vt liu nano t nguyn t hoc chuyn pha.

- Phng php chuyn pha: Vt liu gia nhit sau lm ngui vi tc nhanh

thu c trng thi v nh hnh. Qu trnh tip theo l tin hnh x l nhit

nhm thu c vt liu trng thi tinh th.



- Phng php bc bay nhit: Nguyn t hnh thnh vt liu nano c to ra

bng cc phng php vt l nh bc bay chn khng, phn x, h quang. Vt liu

nano thu c t phng php ny thng l cc mng nano.

Phng php ha hc y l phng php ch to vt liu nano t cc ion hoc nguyn t. Phng

php ny rt ph bin tng hp vt liu nano v nanocomposite. u im ca n

l c th tng hp c tt c cc dng ca vt liu nano nh dy nano, ng nano,

thm ch c cc cu trc nano phc tp m phng sinh hc. Hn na, phng

php ny cn cho php can thip to ra cc vt liu nano vi kch thc nh nh

mong mun vi ng u cao. Ngi ta chia phng php ho hc thnh cc

phng php sau y:

- Phng php kh ha hc: phng php kh ha hc, mui ca kim loi

tng ng c kh vi s c mt ca cc tc nhn lm bn khng ch s ln ln

ca cc ht v ngn cn s keo t ca chng. u im ca phng php ny l quy

trnh thc hin n gin, khng i hi cc thit b t tin, c th iu khin kch

thc nh mong mun v cho php tng hp vt liu vi mt lng ln. Phng

php ny ch yu ch to cc ht nano kim loi.

- Phng php s dng nguyn liu c sn trong t nhin c cu trc nano: Cc

nguyn liu c sn trong t nhin nh zeolit, cc ht st, cc phn t sinh hc c

phn b l xp hoc cu trc l c kch thc nano mt. Cc nguyn liu ny v th

c th lm khun phn ng tng hp vt liu nano v nano composite.

- Phng php s dng mng cht a in ly: Mt s mng cc cht a in ly

thng c dng tng hp vt liu nano v nano composite l polyacrylic

(PAA), polyanlyamin hidroclorua (PHA), plyetylenimit (PEI). Cc mng ny c cc

nhm cacbonyl hoc cc nguyn t nit mang in tch m nn s hp th vi cc

ion kim loi cc phc cht bn trn mng polyme . Sau cc cht kh thch hp



s c s dng kh cc ion kim loi. Sn phm thu c l cc mng cu trc

nano n lp hoc a lp.

- Phng php sol-gel [10, 20]: Phng php sol-gel do R.Roy xut nm 1956.

Phng php sol-gel thng c dng tng hp cc vt liu nano dng bt, si

mng, gmu im ca phng php ny l d iu khin c kch thc ht

nn ht thu c c phn b kch thc ht nh nh mong mun, thit b n gin,

tit kim c nhiu nng lng, mang tnh kinh t hn so vi cc phng php

khc. Phng php sol-gel nhng nm gn y pht trin rt a dng, nhng c th

quy t thnh mt s hng chnh sau:

Phng php sol-gel theo con ng thy phn cc alkoxit: Trong phng php ny, cc hp cht alkoxit thng c ha tan vo dung mi hu c

khan v thy phn bng cch cho thm mt lng nc. S to thnh sol - gel rt

phc tp nhng c th tm tt bng ba qu trnh sau:

- Thy phn alkoxit kim loi M(OR)n

- Qu trnh trng ngng

+ Phn ng loi nc:

+ Phn ng loi ru:

+ Qu trnh gel ha: Cc on polyme lin kt vi nhau thnh khung ba chiu. n

mt lc no , ton b h bin thnh gel, nc v dung mi nm trong cc l ca

gel. Phn ng phn hy ca gel s xy ra nhit thp, cho sn phm c ng

nht v tinh khit ha hc cao, b mt ring ln. Bng cch iu chnh tc

thy phn v tc ngng t, c th khng ch c kch thc ht v hnh dng

ca ht cng nh c th ch to mng mng hoc v nh hnh. Phng php ny



c bit thun li trong vic ch to vt liu oxit kim loi.

Phng php sol-gel theo con ng thy phn cc mui: Phng php ny xut pht t cht u l cc mui nitrat, cloruaCc ion kim loi trong

mi trng nc to phc aquo b thy phn to thnh aquohidroxo

Cc phc aquohidroxo n nhn ngng t thnh phc a nhn ri tip tc pht trin

thnh cc mch polymer.

III.4 Tnh hnh nghin cu v ng dng vt liu nano v vt liu nano

composite [10]:

Hin nay trn th gii vic nghin cu v ng dng cng ngh nano ang

c rt nhiu cc quc gia quan tm. C th k n mt s cng quc ang

chim lnh th trng cng ngh ny hin nay nh: Hoa K, Nht Bn, Trung Quc,

c, Nga v mt s nc Chu u nhng quc gia trn, chnh ph dnh mt

khon ngn sch ng k h tr cho vic nghin cu v ng dng thc tin ca

ngnh cng ngh nano. Khng ch cc trng i hc c cc phng th nghim vi

cc thit b nghin cu quy m m c cc tp on sn xut cng tin hnh nghin

cu v pht trin cng ngh nano vi cc phng th nghim vi tng chi ph nghin

cu tng ng vi ngn sch chnh ph dnh cho cng ngh nano.

Vit Nam, xu hng tip cn vi cng ngh nano trong nhng nm gn

y to ra nhng chuyn bin c sc li cun i vi lnh vc ny. Nh nc

cng dnh mt khon ngn sch kh ln cho chng trnh nghin cu cng ngh

nano cp quc gia vi s tham gia ca nhiu trng i hc v Vin nghin cu

trong c nc. Bc u thu c nhiu kt qu ng khch l. S d m cng

ngh nano c ch trng pht trin nh vy l do nhng ng dng k diu m

cng ngh nano v ang t c trong cc lnh vc ca khoa hc v cng ngh.

Sau y l cc lnh vc m cng ngh nano c u th :



III.4.1. Cng ngh in t, cng ngh thng tin.

Trong cng ngh thng tin nhu cu s dng b nh c dung lng ln ngy

cng cao. Cc nh khoa hc nghin cu v ch to ra cc chip my tnh vi chm

lng t gi l cc chip nano (nano chip) c tch hp rt cao, cho php tng dung

lng b nh ca my tnh. Cng ngh nano cng c ng dng trong ch to cc

linh kin quang in t trong cc mn hnh tinh th lng, thit b pht tia laze... vi

chnh xc c vi nano mt. [19]

III.4.2. Cng ngh ch to my, cng nghip nh.

Cc vt liu nano c nhiu ng dng trong thc t. Do c cu trc c bit

nn ng nano cacbon (cacbon nanotubes) hoc cc t hp composite ca chng c

bn c hc cao gp 10 ln thp, tnh bn nhit cao, v vy, cc ng cacbon l

nguyn liu rt thch hp sn xut cc thit b cho ngnh sn xut xe hi, my

bay, tu v tr

Cc vt liu nano c iu ch di dng aerogel c cu trc xp v xp

cao th lm vt liu cch nhit, kh ting n, cch nhit [20]

III.4.3. Y sinh hc.

- Phn tch v chn lc t bo: Da vo c trng siu thun t ca cc ht nano

st t cc nh nghin cu s dng n tin hnh phn tch t bo. Qu trnh

phn tch c chia lm hai giai on: nh du thc th sinh hc cn nghin cu

thng qua cc ht nano st t. Sau tch cc thc th c nh du ra khi mi

trng bng t trng ngoi.

- Dn truyn thuc: Khi xm nhp vo trong c th, thuc cha bnh thng b

phn tn v khng tp trung gy nh hng cho cc t bo kho mnh, sinh ra cc

tc dng ph. Do ngi ta s dng cc ht t tnh nh l ht mang thuc n v

tr mong mun trn c th (cc khi u, ung th) bng t trng ngoi.

- Tng thn nhit cc b: Phng php ny dng trong cha tr ung th. Cc ht



nano t tnh c phn tn trong cc m b bnh, sau s dng mt t trng

xoay chiu bn ngoi ln v cng v tn s tc dng ln cc ht nano st t,

lm cho cc ht nano hng ng v to ra nhit cc b nung nng t bo ung th

(c 42oC). Ti nhit cc b ny c th git cht cc t bo ung th. [26]

III.4.4. Nng lng mi.

Vi cng ngh nano, ngi ta c th to ra nhng loi pin mi c kh nng

quang hp nhn to, gip con ngi sn xut ra nng lng sch, hay to ra nhng

thit b t tiu tn nng lng do s dng nhng loi vt liu nh nh. Cc mng

nano (vi chi ph sn xut thp) ha hn c th hp th c nhiu nng lng mt

tri hn cc vt liu quang in hin nay. y l khi u cho mt cuc cch mng

trong vic s dng nng lng mt tri.[19]

III.4.5. Cng ngh x l Mi trng

Cc vt liu x l mi trng ang l vn ang c quan tm, c bit l

vt liu dng trong cng ngh lm sch nc. Cc my lc c to ra bi cng

ngh nano vi cc mng lc c ng knh l ch vi nano nh mng lc thm thu

ngc (RO), cc mng vi lcc th lc c cc vi khun v virus trong nc v

c th tch loi c trn 99,8% cc cht tan trong nc[13].

Mi y nh khoa hc ngi Nht pht hin ra mt loi vi khun chuyn

n cc cht l lng trong nc v cc ht nano t tnh. Khi cc vi sinh vt n no

(cht bn ln cc ht nano t tnh), chng s c lng v tch ra khi nc nh t

trng ngoi.

Vt liu nano c din tch v s in t phn b trn b mt ln hn rt nhiu

so vi cc vt liu dng khi. Do vt liu nano xut hin nhiu c tnh ni

tri, c bit l kh nng xc tc, hp ph... Li dng cc u th cc nh khoa

hc v ang i su nghin cu tm ti ch to cc vt liu hiu nng cao, s dng

trong lnh vc x l mi trng: vt liu hp ph, cc vt liu c kh nng xc tc,



x l cc hp cht v c, hu c, cc loi kh thi d bay hi (VOCs)

Chng II

Vt liu v phng php nghin cu:

I- Vt liu nano oxit st t Fe3O4:

I.1. Cu trc tinh th Fe3O4:

Oxit st t Fe3O4 c xp vo

nhm vt liu ferit c cng thc tng qut

MO.Fe2O3 (M l kim loi ha tr 2 nh Fe,

Ni, Co, Mn, Mg hoc Cu). Trong loi vt

liu ferit cc ion oxi c bn knh khong

1,32Ao ln hn rt nhiu bn knh ion kim

loi (0,6 0,8 A) nn chng nm rt st nhau v sp xp thnh mt mng li c cu trc lp phng tm mt. Oxit st t Fe3O4 l mt ferit c cu trc spinel o.

N c mt na s ion Fe3+ chim hc bt din, na cn li chim hc t din, cc

ion Fe2+ u chim hc bt din. Chnh cu trc spinel o quyt nh tnh cht

t ca Fe3O4, l tnh cht feri t.

Bng 1. S phn b cc momen t spin ca cc ion Fe2+ v Fe3+

Cation Hc bt din

(nhm B)

Hc t din

(nhm A)

Momen t ring

Fe3+

Trit tiu hon ton

Fe2+



Trong oxit st t, v ion Fe3+ c mt c hai phn mng vi s lng nh

nhau nn momem t ch do Fe2+ quyt nh.

Trong mi trng khng kh Fe3O4 d b oxy ha v chuyn v dng

-Fe2O3.Fe3O4. -Fe2O3 v Fe3O4 c cu tinh th v tnh cht vt l tng t nh nhau -Fe2O3 cng l cht feri t nhng c Ms nh hn Fe3O4 .

Trn thc t, khi iu ch ht nano st t, ngi ta thy xut hin mt lng

nh -Fe2O3 do Fe3O4 d b oxy ho khi c mt oxy k c trong mi trng lng. I.2. Tnh cht t ca vt liu:

Vt liu Fe3O4 kch thc < 20nm l vt liu siu thun t. Hin tng ny

ch xy ra i vi st t c cu to bi cc ht tinh th nh. Khi kch thc ht ln,

h trng thi a men (tc l mi ht s cu to bi nhiu men t). Khi kch

thc ht gim dn, cht s chuyn sang trng thi n men (mi ht s l mt

men). Hin tng siu thun t xy ra khi kch thc ht gim qu nh, nng

lng nh hng (m chi phi ch yu y l nng lng d hng t tinh th)

nh hn nhiu so vi nng lng nhit, khi nng lng nhit s ph v s nh

hng song song ca cc mmen t, v mmen t ca h ht s nh hng hn

lon nh trong cht thun t [4].

I.3. ng dng ca nano st t

Vt liu nano st t ngy cng c nghin cu k lng nhm pht hin ra

nhng hiu ng mi nh hng cho cc ng dng mi trong sn xut cng nh i

sng. c bit trong lnh vc x l mi trng nano st t kch thc c 20 nm c

kh nng hp ph c hai dng arsenate - As(III) v arsenite - As(V), dung lng hp

ph cao gp 200 ln so vi vt liu dng khi. Khi cn bng hp ph hm lng

asen trong nc c th t di mc 10 ppb (l nng asen cho php theo tiu

chun ca WHO) ch trong vi pht [2]. Ngoi ra rt nhiu nghin cu chng t

rng nano st t ngoi kh nng hp ph asen cn c kh nng hp ph cc kim loi



nng khc nh: ch, niken, thu ngn v c bit c kh nng hp ph rt tt Cr(VI)

khi d pH thp (c pH= 2-3) [14]. Nhng pht hin l nn tng cho mt hng

nghin cu mi: Nghin cu ch to nano st t hoc t hp compossite ca chng

vi cc thnh phn khc nh hng x dng trong x l mi trng. Cc ng dng

chung ca nano st t a ra trn hnh 5.

Hnh 5: Cc ng dng chung ca nano st t

II- Vt liu Mangan dioxit (MnO2):

Manganese dioxide hoc manganese peroxide tn ti di dng cht bt v

nh hnh, mu en, c khi lng ring 5,03 g/cm3. Khi nung n 535oC MnO2

phn hu thnh Mn2O3 v O2. MnO2 khng tan trong nc, tan trong axit. Trong t

nhin, mangan dioxit tn ti trong ba lai khong vt: pyrolusit, ramsdellit,

akhtenskit. Vit Nam, ch ring ngun khong pyrolusit c n hng triu tn tp

trung Cao Bng, Ngh An.



Do cc u im ca mangan dioxit nh l ngun nguyn liu d kim, r

tin, kh nng oxy ha cao, thn thin vi mi trng nn mangan dioxit c cc

nh khoa hc c bit nghin cu v ng dng vo nhiu lnh vc trong i sng.

V d: dng iu ch clo (vi dung dch HCl m c), ch to pin kh (cht kh

cc), sn xut sc t en, men gm, s, ch to hp kim feromangan v cc hp

cht mangan, dng trong cng nghip cao suu im ni tri nht ca mangan

dioxit l kh nng xc tc oxi ha cao. Do vy n c s dng trong cc phn ng

ha hc nh l mt cht xc tc in hnh. S c mt MnO2 trong phn ng phn

hy H2O2 c coi l mt h xc tc d th (rn - lng). Tc dng ca MnO2 l s

hp ph ca cht xc tc i vi H2O2. S hp ph dn ti hin tng tng nng

cc cht tham gia vng b mt cht xc tc, to thun li cho phn ng v mt

nng lng, khin cho phn ng tng. l li gii thch cho hin tng ti sao khi

khng c MnO2, ta khng th nhn thy s phn hy H2O2, cn khi c n th phn

ng xy ra mnh lit [18].

Trong cng ngh mi trng mangan dioxit c s dng kh ph bin x

l mi trng nc v khng kh.

Cc nh khoa hc i Loan pht hin ra rng, s dng MnO2 ng vai tr

nh l mt cht xc tc c th lm gim lng amoni trong ngun nc. Cc kt

qu thc nghim cho thy, s dng MnO2 c th gim 89.5% lng amoni trong

nc, mt kt qu ht sc kh quan. Thm vo , so vi phng php ph bin l

dng TiO2 x l amoni trc y, th phng php ny t tn km hn, em li

hiu qu kinh t cao. Mangan dioxit (MnO2) t lu c s dng trong cng

ngh x l nc sinh hot v nc thi nh l mt loi vt liu c kh nng t xc

tc hp ph cho mc ch x l st v mangan ng thi trong nc. Ngy nay

hng nghin cu ch to MnO2 kch thc nano di dng Black Birnessite ang

c cc nh khoa hc quan tm nghin cu ch to v ng dng x l crm,

asen cng nh cc hp cht hu c trong nc v khng kh.



Cc loi vt liu mi trn c s MnO2 - Black Birnessite c din tch b mt

ring cc ln dng l xp rng (dng t chim - Birds Nest) [15]. Din tch b mt

ln gip to ra nhiu im hp ph hn cho cc phn t d bay hi. Hn na, cc

cht nhim b hp ph phn hy rt c hiu qu do oxi c cung cp cho qu

trnh oxi ha din ra ngay ti mng li ca MnO2.

Hnh 6: nh SEM ca MnO2 - Black Birnessite

iu ny dn n nhng nghin cu ch to cc loi vt liu trn nn nano

MnO2 nhm loi b mt cch hiu qu cc hp cht hu c d bay hI (VOCs), cc

hp cht NOx v SO2. Theo nh gi ca cc nh khoa hc MnO2 c th l vt liu

xc tc oxy ho ca tng lai, chng thm ch c th thay th cc vt liu xc tc

truyn thng rt t tin nh Platin. Hnh 6 l nh SEM ca MnO2- Black Birnessite

phng i khc nhau.

Ti Vit Nam cng c nhiu cng trnh nghin cu s dng MnO2 trn



nn qung pyrolusite loi b asen trong nc (L Vn Ct vi vt liu MF-97,

Bi Quang C). Tuy nhin dung lng hp ph ca vt liu cn rt thp v da

trn c s vt liu dng khi (0,175mg As/kg vt liu).

III - Cc phng php o c, kho st:

III.1. Phng php nhiu x Rnghen ( Xray diffracsion: XRD) [23]

Phng php nhiu x tia X( tia Rnghen) cung cp cc thng tin v thnh

phn cu trc mng tinh th ca vt liu, ng thi n cn cho php tnh c kch

thc trung bnh ca ht tinh th. Nguyn l ca phng php nhiu x tia X l xc

nh kch thc v thnh phn cu trc mng da vo nh hng khc nhau ca

kch thc tinh th ln ph nhiu x.

Khi chiu 1 chm tia X vo tinh th, in t trng ca tia X s tng tc vi

cc nguyn t nm trong mng tinh th. Cc nguyn t, ion b kch thch bi chm

tia X s tr thnh cc tm pht ra cc tia phn x. S tia ti v tia phn x c

trnh by trn hnh 7.

Hnh 7: S tia ti v tia phn x

Cc tia phn x t tng tc ny c th giao thoa vi nhau v xy ra hin

tng nhiu x. Nu gi gc ti ca tia X vi mt phng tinh th l th s giao thoa ch c th xy ra nu phng trnh Vuff- Bragg c tha mn:



2d sin = n Trong :

d : l khong cch gia hai mt phng song song

: gc gia chm tia X v mt phng phn x : l bc sng ca tia X Detecter s ghi nhn li tt c cc tia nhiu x. Hnh nh nhiu x s c

trnh by di dng mt nhiu x . Sau khi ghi ph, my s so snh vi th vin

cc ph chun xc nh cc pha c trong mu, cu trc v t phn pha ca mu.

C th tnh c kch thc trung bnh ca ht bng cng thc Debye-

Scherrer:

Trong :

d : l kch thc ht trung bnh (nm)

: l rng na vch ph ca pic cc i ( rad) Do nhng tnh nng trn m phng php ny c dng kh ph bin trong

nghin cu cu trc tinh th.

III.2. Phng php knh hin vi in t qut (SEM).

Phng php SEM c s dng kho st hnh dng v cu trc b mt

ca vt liu. Hnh 8 a ra ton cnh h knh him vi in t phn gii cao Hitachi

S-4800 t ti phng th nghim trng im ca vin Khoa hc Vt liu - Vin

KH&CN Vit Nam



Hnh 8: Ton cnh h knh him vi in t phn gii cao Hitachi S-4800

Nguyn tc c bn ca phng php SEM l dng chm in t to nh

ca mu nghin cu, nh khi n mn hunh quang c th t phng i ln

n 100.000 ln. Chm electron c to ra sau khi ra khi thu knh hi t s c

hi t ln mu nghin cu. Cc electron p vo mu, b phn x to thnh mt tp

hp cc ht th cp i ti detecter. Ti y electron s c chuyn thnh tn hiu

in. Cc tn hiu in sau khi c khuych i i ti ng tia catot v c qut

ln nh. Cc vng ti hay sng trn nh ph thuc vo s cc ht th cp p vo

ng tia catot. u im ca phng php SEM l c th thu c nhng bc nh ba

chiu r nt v hnh dng v cu trc b mt vt liu.

III.3. Phng php ph hng ngoi (FTIR)

Ph hng ngoi dng xc nh cu trc phn t ca phn t cht nghin

cu da vo cc tn s c trng trn ph ca cc nhm chc trong phn t. Khi

chiu bc x hng ngoi vo phn t cht nghin cu, trong bn thn cc phn t

lun c trng thi dao ng. Qu trnh tng tc dn n s hp th nng lng

c lin quan cht ch n cu trc ca cc phn t. Phng trnh c bn ca s hp

th bc x in t l phng trnh Lanbert-Beer:

A = lgIo/I =.L.C



Trong A l mt quang. Io , I l cng bc x trc v sau khi ra khi

cht phn tch. C l nng cht phn tch (mol/lit). L l b dy cuvet (cm), h s

c trng cho hp th phn t.

ng cong biu din s ph thuc ca mt quang vo chiu di bc

sng gi l ph hp th hng ngoi. Mi cc i ph hng ngoi c trng cho mt

dao ng ca mt lin kt trong phn t.

Nguyn l ca phng php l s dng mt ngun bc x pht ra mt chm

tia hng ngoi vi mi tn s trong vng cn o. Chm tia ny c tch thnh hai

phn, mt phn i qua mu v mt phn i qua mi trng cn o ri n b phn

giao thoa. Bc x hng ngoi sau khi i qua b phn giao thoa k s i qua mu ri

n detector. Di tc dng ca bc x hng ngoi, cc nhm chc trong phn t

mu s dao ng ng vi bc sng m n hp th. Detector s so snh cng

hai chm tia (mt i qua mu v mt i qua mi trng cn o) cho ra cc tn

hiu c cng t l vi phn b hp th bi mu. My tnh s ghi li s hp th

bc x ca mu di dng ng cong ch s ph thuc phn trm bc x truyn

qua vo s sng (cm-1).

III.4. Phng php o t trn h t k mu rung (VSM).

kho st tnh cht t ca vt liu nano oxit st t s dng phng php o

t trn h t k mu rung (VSM). T l mt i lng c trng cho tnh cht t

ca vt liu. ng t cong t ha v t tr cho ta bit cc thng s nh t bo

ha (Ms), lc khng t (Hc), cm ng t d (Bs). V t c th a ra nhng nh

gi s b v tnh cht t ca vt liu. Nh ni, t k mu rung hot ng theo

nguyn tc cm ng in t. N o mmen t ca mu cn o trong t trng

ngoi. Mu o c gn vo mt thanh rung khng c t tnh, v c t vo mt

vng t trng u to bi 2 cc ca nam chm in. Mu l vt liu t nn trong t

trng th n c t ha v to ra t trng. Khi ta rung mu vi mt tn s nht

nh, t thng do mu to ra xuyn qua cun dy thu tn hiu s bin thin v sinh



9

vi M l mmen t ca mu o, Sm l tit din

vng dy, n l s vng dy ca cun dy thu

tn hiu. Trn hnh 9 a ra nh chp t k

mu rung VSM 880 - Trung tm KHVL -

Trng i hc Quc gia H Ni.

III.5. Phng php xc nh hm lng Asen trong nc.

Phng php c s dng xc nh hm lng asen trong nc l phng

php hp ph nguyn t (AAS) trn my AAS 6800 Shimadzo - Nht Bn. K thut

ny rt thch hp phn tch cc nguyn t c hm lng vi lng 5ppm v siu vi

lng nh As m khng cn lm giu asen. Phng php ny nhy cao, kt qu

phn tch n nh.

III.6. Phng php xc nh hm lng Cr(VI) trong nc.

Phng php c s dng xc nh hm lng crom trong nc l

phng php o quang trn my UV-VIS Shimadzo- Nht Bn. K thut ny rt

thch hp phn tch cc nguyn t vi lng trong nc. Phng php c nhy

cao, kt qu phn tch n nh.




Chng iii

thc nghim

I. Tng hp ht nano oxit st t Fe3O4 bng phng php ng kt ta:

I.1. Ha cht v dng c

I.2. Phng php ch to vt liu v c ch phn ng:

C rt nhiu phng php ch to cc ht nano oxit st t, tuy nhin trong

ti ny chng ti s dng phng php ng kt ta trong dung dch bng con

ng thy phn cc mui st. Phn ng ho hc to kt ta Fe3O4 xy ra nh sau:

Hai loi mui st c la chn trong lun vn ny l FeCl2.4H2O v

FeCl3.6H2O. Dung dch c chun b trong nc ct bo ho kh Ar. Theo cc tnh

ton nhit ng, vi t l Fe2+/ Fe3+ =1:2, trong dung dch c mt ion Cl-, Fe3O4 c

to thnh trong khong pH kh rng t 5-14. Tuy nhin, trong qu trnh iu ch,

dung dch thng c duy tr pH cao 11- 13 m bo cung cp ion OH- cho

phn ng, pH ca hn hp c gi khng i trong sut qu trnh.

Phng php ng kt ta l mt trong nhng phng php thng c

dng to cc ht oxit st t. u im ca phng php l n gin, d ch to,

cho kt qu nhanh, chi ph thp. Tuy nhin phng php ny cng c mt s cc


nhc im nh: phn ng phi tin hnh trong mi trng kh tr v kh iu

khin ng u kch thc ht.

I.3. Quy trnh tng hp ht nano st t [6]

- Chun b dung dch NaOH nng 4M v dung dch HCl nng 0,4M. Dung dch c chn b bng nc ct bo ha Ar.

- Ly 106 ml dung dch NaOH nng 4M pha vi nc ct bo ha kh Ar thnh 425 ml dung dch v cho vo bnh cu hai c 1000 ml. Dung dch c khuy

trn bng my khuy t v sc kh Ar.

- Cn 8,6g FeCl2.4H2O v 23,3g FeCl3.6H2O (t l Fe2+/ Fe3+ =1:2), thm 64 ml

dung dch HCl nng 0,4M, nh mc thnh 500ml.

- Dung dch hn hp c cp vo thit b phn ng vi tc 60 git/ pht. Qu trnh phn ng din ra trong mi trng pH cao11- 13, sc kh Ar v nhit

phng. Phn ng to kt ta mu en.

- Kt thc phn ng, tip tc khuy trn v a nhit dung dch ln 80oC lm gi ha sn phm trong 30 pht.

- Kt ta c em gn ra vi nc ct nhiu ln n khi pH t trung tnh. Sn phm sau c sy trong mi trng chn khng, thu c sn phm dng

bt mu en.

Hnh 10: Vt liu Fe3O4 ch to



II. Ch to nano composite st t bc mangan dioxit - Fe3O4/MnO2 bng

phng php ng kt ta trong dung dch:

II.1. Ha cht v dng c

Ha cht: Cc ho cht MnSO4.H2O v

(NH2)2CO l cc ha cht tinh khit ca Trung

Quc,

- Nc ct bo ho Ar

- Vt liu Nano Fe3O4 t ch to.

Dng c ch to (a ra trn hnh 10) bao gm:

- Bnh cu hai c 5000 ml

- My khuy c

- Phu thu tinh nh git

- Bnh kh Ar.

- Bp iu khin nhit, nhit k t ngt

II.2.Phng php ch to v c ch phn ng:

Qu trnh ch to nano composite st t Fe3O4/ MnO2 c thc hin bng

phng php ng kt ta trong dung dch. Dung dch mangan l MnSO4.H2O.

iu chnh pH s dng Ur. Phn ng c thc hin ti nhit 80 - 85C tng hiu qu phn hy Ur. Thi gian tin hnh phn ng l 12 gi. Thu c sn phm

mu nu en. Tin hnh ra nhiu ln trong nc ct n khi pH t trung tnh, ly

tm, sy sau nung ngoi khng kh trong 3 gi ti 280oC [7]:

Qu trnh phn hu Ur :



Cc phn ng tip theo

Kt qu l to ra c mt vt liu c li l oxit st t v bao bc bn ngoi l mng

mangan dioxit.[8]

II.3. Quy trnh bc mangan dioxit ln st t:

- Cn 1,5g ht nano st t cho phn tn trong 300ml dung dch PEG 15% (dung dch 1).

- Cn 1,824g MnSO4.H2O pha thnh 300ml dung dch vi nc ct bo ha (dung dch 2).

- Cn 3,24g (NH2)2CO pha thnh 30ml dung dch vi nc ct bo ha (dung dch 3)

- Trn dung dch (1) vi dung dch (2) c hn hp dung dch. Dung dch hn hp ny c em siu m trong 20 pht trc khi tin hnh phn ng. - Phn ng c tin hnh trong thit b khuy c sc kh Ar. Dung dch 3 c cp vo hn hp dung trn vi tc cp l 60 git/pht.

- Sau khi dung dch 3 c cp ht, a hn hp phn ng ln nhit 800C.

Phn ng din ra trong 12h, trong mi trng c pH cao 11-12, thu c dng

huyn ph mu nu en.

Hnh 12: Vt liu nano composite st t Fe3O4/ MnO2 ch to




- Sau phn ng, sn phm c ra bng nc ct nhiu ln n khi pH t

trung tnh. Sn phm c sy kh trong khng kh nhit 800C v nung ti

2800C trong 3h, thu c vt liu dng bt mu nu en.

III- Xc nh kh nng hp ph asen v crm ca vt liu

III.1. Ho cht v dng c th nghim

Ha cht :

- Vt liu Fe3O4/MnO2 - Dung dch As(V) - Dung dch Cr(III)

Dng c th nghim:

- Bnh tam gic 100ml - Giy lc - My khuy c hc

III.2. Qu trnh thc nghim:

Dung dch Cr(III) v As(V) c chun b trong nc ct bo ho kh Ar. Vt

liu trc khi hp ph asen c x l trn my siu m trong 5 pht. Nng pha

rn c gi c nh l 0,1g/l, pH ca dung dch c gi trong khong 6,5-8. Tt

c cc th nghim u c thc hin nhit phng v c khuy lin tc. Thi

gian ly mu ln lt l 10, 20, 30, 60 v 120 pht. Hnh nh h thng th nghim

a ra trn hnh 13:

Hnh 13: Hnh nh h thng th nghim hp ph asen v crm


xc nh kh nng hp ph crm v asen ca vt liu ta c hai dy th

nghim sau:

Hiu ng hp ph As v hiu ng hp ph cnh tranh khi c Cr(VI) Dung dch cha 100 ppb As(V)/ lt. Nng pha rn l 0,1g Fe3O4 / MnO2.

iu chnh pH= 6,5-8. Nng Cr(VI) trong cc th nghim ln lt l : 0, 0.05,

0.10, 0.02

Kh nng hp ph crm ca vt liu. Nng pha rn l 0,1g Fe3O4/ MnO2+, iu chnh pH= 2,5. Nng crm

trong dung dch ln lt l 50, 100, 150 mg/l, thi gian ly mu ln lt l: 5, 15,

30, 60, 120 pht. Mu c em lc loi b cn rn sau dc phn tch hm

lng crm cn li trong dung dch.

III. Th nghim mt mu dung dch methyl da cam:

III.1. Ha cht v dng c th nghim:

Ho cht

- Axit H3PO4 0.1M

- Dung dch methyl da cam 0,2mg/l

- Vt liu Fe3O4/MnO2

Dng c th nghim:

- Bnh tam gic 100ml

- My khuy c hc

- Giy lc

III.2. Qu trnh thc nghim:

III.2.1. Th nghim mt mu dung dch methyl da cam ca vt liu nano

Fe3O4/MnO2 khi thay i pH.

Ly 0,05g Fe3O4/MnO2 cho phn tn trong 50ml dung dch methyl da cam

nng 0.2mg/l vi cc gi tr pH theo dy: 1, 1.3, 1.5, 2, 3, 3.5, 5. Thi gian phn

ng l 30 pht. Tt c cc th nghim u c thc hin nhit phng v c

khuy lin tc. Mu sau khi ly lc sch v o mu bng my DR 4000U

Qun Th Thu Trang MSSV: 505303065 2


Spectrophotometer. T tnh ra t l mt mu v xc nh khong pH ti u cho

phn ng.

III.2.2. Th nghim mt mu dung dch methyl da cam ca vt liu nano

Fe3O4/MnO2 khi thay i thi gian phn ng.

Ly 0,05g Fe3O4/MnO2 cho phn tn trong 50ml dung dch methyl da cam

nng 0.2mg/l. pH ca dung dch c iu chnh khong 1,3. Tt c cc th

nghim u c thc hin nhit phng v c khuy lin tc. Thi gian ly

mu ln lt l 10, 20, 30, 60 v 120 pht. Mu sau khi ly lc sch v o mu

bng my DR 4000U Spectrophotometer. T tnh ra t l mt mu v xc inh

khong thi gian thch hp cho phn ng.



Chng IV

Kt qu v tho lun:

I- Cc c trng c bn ca vt liu:

I.1. Gin XRD ca vt liu:

Gin nhiu x XRD ca hai mu vt liu c a ra trn hnh 14. Trn

gin XRD ca c hai mu u xut hin cc pic c trng cho cu trc spin o

ca st t, cc pic ny c k hiu l A. Tuy nhin, v oxyt st t Fe3O4 v

maghemite -Fe2O3 c cng cu trc vi v tr cc vch pic ging nhau trn ph XRD, chng ch khc nhau v cng tng i nn cn phi kt hp thm vi d

liu ph hng ngoi khng nh thnh phn pha ca vt liu.

Hnh 14: Gin XRD ca mu vt liu nano st t- Fe3O4

v nano st t bc mangan dioxit-Fe3O4/MnO2

Trn gin XRD ca mu MN-2 ta c th nhn ra s c mt ca hai pic ti

2=28.5 v 2=37.5 , k hiu l B. Cc pic ny c gn cho MnO2. Nh vy c th



khng nh trong thnh phn ca vt liu c mt MnO2. Cc thng tin thu c trn

ph nhiu x tia X cng cho thy cc ht vt liu c kch thc rt nh do rng

vch nhiu x y l ln. Ngoi ra c th thy rng vt liu MN-2 c kch thc

ln hn MN-1.

I.2. Ph FTIR ca vt liu:

Hnh 15 v 16 l ph FTIR ca mu nano st t Fe3O4 v mu st t bc

mangan dioxit Fe3O4/MnO2. Ta c th nhn thy cc vn hp th c trng ca oxit

st t khong 564,15cm -1 v 412,67 cm -1 i vi mu MN-1 v 567,25 cm -1 i

vi mu MN-2. Chng u nm trong ngng vch c trng cng sng ca

oxit st t t 500-700 cm -1. Ngoi ra mu MN-2 ta cn thy s xut hin thm

vn hp th yu 646 cm -1. Vn ny c gn cho maghemite -Fe2O3 [7].

Hnh15: Ph PTIR ca mu nano st t Fe3O4

Nh vy, trong thnh phn ca MN-2 c mt mt phn -Fe2O3. Tuy nhin v

cu trc v tnh cht, Fe3O4 v -Fe2O3 c rt nhiu im tng ng nn cng c

th d on s c mt ca -Fe2O3 s khng to ra s khc bit ng k v tnh

nng hp ph asen hay crm ca vt liu. Trn ph FTIR ca mu MN-2 cn thy

xut hin vn hp th ti 601.39 cm -1, vn hp th ny chng t s c mt ca



mangan dioxit MnO2 trong thnh phn mu vt liu MN-2.

Hnh 16: Ph FT-IR ca mu st t bc mangan dioxit Fe3O4/MnO2 chp di t

450 -750 cm-1(a) v di 600-4000 cm-1 (b)

Vn hp th ti 3454.86 cm -1 c gn cho lin kt -OH pha trn b mt ca

vt liu, m y l mu MN-2. Vn hp th ny c b rng v vch r rng hn




rt nhiu so vi mu vt liu MN-1. iu c ngha l vt liu MN-2 c nhiu gc

hydroxyl hn so vi vt liu MN-1, hay l vt liu MN-2 c kh nng hot ho hn

so vi vt liu MN-1.

II.3. Hnh thi hc ca vt liu:

Hnh 17: nh SEM ca MN-1(a), MN-2 (b) v (c) l nh SEM ca vt liu MN-2 quan st mc 500nm

Hnh 17a v 17b l hnh chp SEM ca hai mu vt liu MN-1 v MN-2.

Ti hnh chp ca hai mu, chng ta nhn thy c hai mu vt liu u c dng gn

(C)

(M)


nh l hnh cu, ng knh ht khong t 12-15 nm. Tuy nhin cc ht mu vt

liu MN-1 c ng u hn v kch thc v hnh dng hn so vi mu vt liu

MN-2.

Hnh 17c l nh chp SEM ca vt liu MN-2 quan st mc 500nm. Quan

st nh chp ta thy, cc ht vt liu MN-2 khng ch c dng hnh cu m cn c

c dng hnh cnh khi di (ht M trn hnh 17c). Chng c kch thc ln hn so

vi kch thc cc ht nano trung bnh, khong 17-20 nm. iu chng t c

s hnh thnh lp mng ln pha bn ngoi li nano st t. Tuy nhin t l cc ht

ny cha cao, cha c s ng u v hnh dng. Nguyn nhn ca s khng ng

u ny l do c im ca phng php iu ch v cc iu kin phn ng nh

hng n kh nng phn hy ca Ur lm cho tnh ng nht trong dung dch cha

cao.

nh SEM ca mu vt liu MN-1 cn cho thy gia cc ht c s kt m do

c im ca phng php iu ch nh ch ra trong cc ti liu. i vi nh

SEM ca mu MN-2, do cc ht nano st t c bc bn ngoi mt lp mangan

dioxit, bn cnh cn c mt ca cht hot ng b mt khng ion (PEG) m ta

thy cc ht vt liu c s phn tn tt hn so vi mu MN-1.

I.4. Tnh cht t ca vt liu:

Tnh cht t ca hai loi vt liu c nh gi qua php o s ph thuc ca

t ho M vo t trng ngoi M(H) nhit thng (hnh 18). ng cong t

ho khi tng v khi gim t trng ngoi ca c hai vt liu gn nh trng nhau, gi

tr t khng Hc ~0 ca mu MN-1 v MN-2 chng t vt liu ch to c c

tnh cht siu thun t - vt liu s khng cn t tnh khi ngng tc ng ca t

trng ngoi [24].




Hnh 18: ng cong t ho ph thuc cng t trng ngoi

T php o ny t bo ho o c i vi mu MN-1 l 56,9 emu/g v

50 emu/g i vi mu MN-2. Mu MN-2 c t bo ha nh hn so vi mu MN-

1 chng t l mangan dioxit c bc bn ngoi cc ht nano st t, do vy m

t bo ha b gim xung. Hn na, trong mu MN-2 c mt phn maghemite -Fe2O3 (hnh thnh trong qu trnh nung), cng l mt nguyn nhn dn n vic

gim t tnh ca vt liu (t tnh ca -Fe2O3 thp hn so vi Fe3O4: dng khi, t bo ho ca Fe3O4 khong 83 emu/g, -Fe2O3 - 75 emu/g) [25]. II- Kho st hiu ng hp ph ca vt liu

II.1. Kh nng hp ph crm v asen ca vt liu:

Cc kt qu o c Hp ph As(V) khi c c Cr(VI) cnh tranh vi dung dch u cha 100 ppb As( V) nng pha rn 0,1g/l a ra trn bng 2:


Bng 2: Hiu ng hp ph As khi c Cr(VI) cnh tranh

T (pht) 10 20 30 60 120

C A B A B A B A B A B

0 12 88 13 87 13 87 7 93 8 92

5 7 93 7 93 10 90 5 95 10 90

10 7 93 6 94 5 95 5 95 7 93

20 39 61 4 96 5 95 2 98 2 98

K hiu: - Nng asen trong dung dch l A (ppb), Hiu xut s l (%) l B, Nng

Crm cnh tranh trong dung dch l C- (ppb), Thi gian ly mu l T

Hnh 19: th ph thuc nng As trong dung dch vo thi gian hp ph i

vi tng nng crm cnh tranh khc nhau ca vt liu MN-2 v th hp ph

asen ca vt liu MN-1

Hnh vi hp ph asen ca vt liu MN-2 th hin rt r rt, tc hp ph rt

cao. Vi hm lng pha rn c 0,1 g/l ch trong thi gian 10 pht c th gim hm

lng asen trong dung dch t 100 ppb xung di ngng an ton ca WHO. Nu



so snh kh nng hp ph ca vt liu nano st t kch thc 12nm khng bc

MnO2 vi vt liu bc MN-2 c th nhn thy r rng l kh nng hp ph ca MN-

2 tt hn nhiu.

Crm v asen c a vo dung dch theo t l nhm xc nh hiu ng hp

ph cnh tranh ca crm vi asen. Kt qu cho thy, s c mt ca crm trong dung

dch dng nh khng nh hng nhiu n s hp ph asen ca vt liu. Khi hm

lng crm bng 20ppm th cng ch sau khong thi gian l 20 pht, hiu sut hp

ph asen t 96%, hm lng asen gim xung di mc tiu chun ca WTO.

Kt qu o c kh nng hp ph crm ca vt liu c a ra hnh 20 v bng 3.

Bng 3: Hiu sut hp ph Cr ca vt liu nano Fe3O4/ MnO2 (%)

Thi gian

(pht)

Nng

Cr(ppb)

Hiu sut hp ph (%)

0

5

15

30

60

120

150 0 65.5 67.2 69.9 69.9 69.9

100 0 80 81.6 84.6 84.6 84.6

50 0 94.5 96.4 97.8 98.3 98.3



Hnh 20: th hp ph Cr ca vt liu nano Fe3O4/ MnO2

Trn hnh 20 chng ta thy vt liu c kh nng hp ph rt tt Cr(VI) khi

pH=2,5. Qu trnh hp ph din ra theo hai giai on: Giai on u ch sau 5 pht

tip xc vi hm lng pha rn l 0,1g/l v nng Cr(VI) trong dung dch l

50ppb, 100ppb, 150ppb th hiu xut hp ph t 93%, 80%, 65%. giai on

tip theo, sau 30 pht qu trnh hp ph t cn bng v hiu sut hp ph t

98.3%, 84.6% v 69.9%. Nu so snh vi cc thng bo hp ph Cr(VI) trn nn

vt liu than hot tnh v than bn th vt liu xp nano composite Fe3O4/ MnO2 c

kh nng hp ph cao vi tc hp ph nhanh hn hn - Thi gian t cn bng

ca than hot tnh khi hp ph Cr(VI) l 10 - 50 gi cn i vi than bn l 6 gi.

II.2. Th nghim mt mu dung dch methyl da cam

Cc th nghim mt mu methyl da cam ph thuc vo mi trng pH c thc hin vi hm lng pha rn 1g/l trong thi gian l 30 pht vi pH thay i

theo kt qu a ra trn bng 4:



Bng 4: S liu % mt mu methyl dacam khi thay i pH

pH 1,0 1,3 1,5 2 3 3,5 5

% mt mu 83,5 97,9 87,5 78,0 50 18,7 4,0

Hnh 21: T l mt mu methyl da cam ph thuc vo pH

Biu din bin thin ca % mt mu methyl dacam theo pH a ra trn hnh

20. Chng ta nhn thy kh nng lm mt mu tt nht pH nh c 1,3 ch sau 30

pht vt liu lm mt mu methyl da cam n 97,9%.

Th nghim mt mu methyl da cam ph thuc vo thi gian c thc hin trong mi trng pH thp pH = 1,3, vi cc khong thi gian l 10, 20, 30, 60, 120

vi hm lng pha rn 1g/l . Cc s liu th nghim a ra theo bng 5

Bng 5: S liu % mt mu methyl dacam theo thi gian khi pH=1,3

Thi gian

(pht)

10

20

30

60

120

T l mt mu

(%)

95.5

97.6

97.9

97.9

97.77



Biu din bin thin ca % mt mu methyl dacam theo thi gian a ra trn

hnh 22.

Hnh 22: th nh hng ca thi gian n t l mt mu methyl da cam

ca vt liu Fe3O4/MnO2

Vi hm lng pha rn 1g/l ch trong thi gian l 10 pht th t l mt mu

dung dch t ti 95,5%. V t l ny t mc cao nht l 97,9% trong thi gian

l 30 pht. Kt qu cho thy vt liu nano Fe3O4/MnO2 khng ch l vt liu c kh

nng hp ph asen, crm m cn l vt liu c kh nng xc tc oxy ho hp ph

cc hp cht hu c rt tt.



Kt lun T cc kt qu nghin cu thc nghim: Ch to vt liu, o c v kho st

thc hin trong ti c th rt ra mt s cc kt lun sau:

ch to thnh cng vt liu bt xp nano composite st t Fe3O4/ MnO2 trong Fe3O4 nh l li c kch thc 12-15 nm c bc bn ngoi mt lp

mangan dioxit - MnO2 dy khong 3 -5 nm.

o c, nh gi cc c trng c bn ca vt liu ch to.Vt liu nano composite st t Fe3O4/ MnO2 ch to c l vt liu siu thun t vi t

bo ha o c l 50 emu/g. So vi vt liu nano st t ch to c ban u

th vt liu nano Fe3O4/ MnO2 c phn tn cao hn.

Vt liu bt xp nano composite st t Fe3O4/ MnO2 c kh nng hp ph asen cao vi tc hp ph kh nhanh. Vi hm lng pha rn c 0,1 g/l ch

trong thi gian 10 pht c th gim hm lng asen trong dung dch t 100

ppb xung di ngng an ton ca WHO. Kh nng hp ph ca vt liu

nano composite st t Fe3O4/ MnO2 cao hn hn so vi vt liu nano st t

khi cng mt iu kin. S c mt ca crm trong dung dch dng nh

khng nh hng n s hp ph asen ca vt liu.

Vt liu bt xp nano composite st t Fe3O4/ MnO2 c kh nng hp ph tt crm (VI) khi pH c 2,5. Qu trnh hp ph din ra vi tc nhanh ch

sau 5 pht tip xc vi dung dch cha 50ppb Cr(VI) hiu xut t ti

93%, v sau 30 pht qu trnh hp ph t cn bng v hiu xut t

98,3%. Kt qu trn gi m kh nng ng dng vt liu nhm x l nc thi

nhim crm c bit i vi nc thi ca cc nh my m (v nc thi ca

cc nh my ny thng c pH thp). Vt liu nano Fe3O4/MnO2 ngoi kh nng hp ph asen, crm cn l vt liu

c kh nng xc tc hp ph cc hp cht hu c rt tt. Th nghim mt mu



dung dich methyl da cam cho thy, t l mt mu t cao nht l 97,9 % trong

mi trng pH ti u l 1,3.

Vt liu bt xp nano composite st t Fe3O4/ MnO2 l vt liu c kh nng hp

ph rt tt vi cc kim loi nng (Cr, As) v cc hp cht hu c. y l vt liu

mi ha hn nhiu tnh ng dng cao trong cng ngh x l mi trng, c bit l

trong lnh vc x l nc. Cc kt qu trn bc u nh hng cho cc nghin

cu tip theo. c th a vt liu vo s dng trong thc t cn c nhng nghin

cu su hn v cc yu t nh hng n qu trnh hp ph, dung lng hp ph v

qu trnh hp ph trong dng chyCn thit phi nghin cu thay th vt liu tinh

khit bng cc vt liu k thut nhm lm gim gi thnh vt liu.



TI LIU THAM KHO

1. Lu c Hi, Vn i, V Cng Nghip, Trn Mnh Liu, Chin lc qun

l v gim thiu tc ng nhim asen ti mi trng v sc kho con ngi,

Tuyn tp Hi tho quc t nhim As: hin trng, tc ng n sc kho con

ngi v gii php phng nga., H Ni thng 9/2005

2. Asenic Contamination in Asia, A world bank and water and sanitation program

report, Mar.2005

3. Hong Th Trung Hiu, Tch loi asen trong nc bng mangan oxit t nhin

4. V nh C, T hc, NXB Khoa hc k thut.

5. Phm Vn Lm, Phan Th Ngc Bch, o Quc Hng , Ch to, kho st cc

c trng v hiu ng hp ph Asen ca cc vt liu oxit st t kch thc nano.

Tp ch Ha hc T- 45, 11-15 (2007).

6. Phan Th Ngc Bch, Nguyn Th Kim Thanh, Phm Vn Lm, iu ch nano

oxyt st t Fe3O4 bng phng php ng kt ta v phng php phn hu nhit.

Phn 1. Phng php ng kt ta iu ch Fe3O4, Tp ch Phn tch Ha L v

Sinh hc T-12, 4 (2007) tr. 14-18

7. Shu Zhang, Shulin Wang, Synthesis and Characterization of Magnetic Nano-

sized Fe3O4/MnO2 Composite Particles, Institute of Chemical Processing

Machinery, Department of Power Engineering, University of Shanghai for Science

and Technology, 516 Jungong Rd, Shanghai 2003, China.

8. Robert E. Simson II, Craig Habeger, A. Rabinovich and James H. Adair,

Enzyme Catalyzed Inorganic Precipitation of Aluminum Basic Sulfate, Deparment

of Materials Science and Engineering, University of Florida, Gaines ville, Porida



9. Sutha Khaodhiar, Mohammad F. Azizian, Khemarath Osathaphan and Peter O.

Nelson, Copper, Chromium, and Arsenic adsorption and equilibrium modeling in

iron-oxide-coated sand, background electrolyte system, Deparment of Civil,

Contruction

10. Nguyn c Ngha, Ho hc nano- cng ngh nn v vt liu, Nh xut bn

Khoa hc t nhin v Cng ngh - H Ni 2007

11..1http:// www.moitruongnuoc.com

12. Th Trm Anh, Tng hp v kho st cc hot tnh SERS v khng khun

ca vt liu Ag nano trn cht mang Silica, lun vn thc s khoa hc ha hc, i

hc S phm H Ni

13. Ngy Hu Tm, Cng ngh nano - hin trng, thch thc v nhng siu

tng, NXB Khoa hc v k thut, H Ni, 2004

14. Removal of Cr(VI) by Magnetite (Fe3O4) nanoparticles

15. Description of Nanofibrous MnO2 Birds-Nest Superstructure Catalyst Taiwan

Patent No. 139,071 (Dec 17, 2001)

16 Nguyn Th Oanh, Kha lun tt nghip, i hc Khoa hc T nhin - i hc

Quc gia H Ni, 2006.

17. V nh C , Nguyn Xun Chnh, Cng ngh nano iu khin n tng phn

t, NXB Khoa hc k thut, H Ni, 2004

18. http:// www.vinachem

19. http:// www.vnpost.mpt.gov.vn

20. M. Wilson et al, Nanotechonology - Basic sience and emerging technology,

CRC Press, 2002.

21. http:// ntt.org

22. http:// vi.wikipedia.org

23. V ng , Cc phng php vt l trong ha hc, NXB i hc Quc gia

H Ni, 2004



24. Kenneth J. Klabunde, Nanoscale materials in chemistry, Wiley-interscience,

John Wiley & Son, Inc., Publication 2001, p. 179-221

25. Preparation and synthesis of magnetic fibers , United States Patent 5143583

26.Ch to v ng dng ht nano t tnh trong sinh hc, Bo co ti Hi ngh Vt

l ton quc ln t 6, 2005.




Li cm n

Vi lng bit n su sc ti xin gi li cm n ti KS. Phm Vn Lm -

hng dn chnh tn tnh ch bo, gp v to mi iu kin thun li cho ti

nghin cu, thc nghim trong sut thi gian thc hin n tt nghip ny.

Ti cng xin gi li cm n n TS. Phan Hng quan tm v ng

vin ti trong sut thi gian va qua.

Ti xin chn thnh cm n n cc thy c gio trong Khoa Cng ngh sinh

hc v Mi trng - Trng H Phng ng dy bo ti trong sut bn nm

hc, ti c c kin thc nh ngy hm nay.

V cui cng, ti xin cm n n tp th Ha V c - Vin Ha hc, ni ti

thc tp gip , to iu kin cho ti hon thnh n ny, bn cnh ,

khng th khng k n l s gip , ng vin to ln ca gia nh, ngi thn v

bn b.

Mt ln na, xin gi li cm n chn thnh nht n tt c mi ngi.

H Ni , Thng 5 nm 2009

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Tổng Hợp Vật Liệu Nano Composite