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Kha lun tt nghip GVHD: Ths Nguyn Th Hng

SVTH: Nguyn Th Hoa Lp 08CHP Trang 1



M U

Trong giai on hin nay, vic thc y pht trin kinh t cng vi qu trnh cng

nghip ha v hin i ha ngy cng gia tng, kinh t pht trin i sng con ngi

ngy mt c nng cao hn, hin i hn, nhng song song vi nhng mt tch cc

y th vic cng nghip ha hn i ha cng em li mt tri ca n l lm cho mi

trng b nhim, c bit l mi trng nc.

Nh chng ta bit, nc l ngun ti nguyn thin nhin qu gi, l yu t

khng th thiu c cho mi hot ng sng trn tri t, mi trng nc chim 2/3

din tch tri t, n ng vai tr rt quan trng. Tuy nhin qu trnh th ha, cng

nghip ha v thm canh trong nng nghip ngy cng pht trin nh hng xu n

ngun ti nguyn ny. Nhiu ni ngun nc b mt, thm ch c nc ngm b

nhim gy nguy him i vi sc khe con ngi. Vic mi trng nc b nhim l

iu v cng bt li, nh gi mc nhim ngun nc hin nay l mt vn ht

sc cp thit t c bin php x l kp thi, chng ta cn phi nghin cu gim

thiu s nhim mi trng nc, vi chnh mc ch chng ti nghin cu ti

Nghin cu xc nh tng hm lng st trong nc bng phng php trc

quang phn t UV-VIS vi thuc th o-phenantrolin. y l phng php c

nhy v chnh xc cao, ph hp vi iu kin th nghim ca nh trng.

Mc ch ca ti nhm:

Nghin cu iu kin ti u v xy dng quy trnh phn tch xc nh hm lng

st trong mi trng nc.



CHNG 1: TNG QUAN TI LIU

1.1. St v d lng ca n trong mi trng

1.1.1. Gii thiu v st [3]

1.1.1.1. Tnh cht vt l

St l tn mt nguyn t ha hc trong bng h thng tun hon.

K hiu: Fe

S hiu nguyn t bng 26.

Nm phn nhm VIIIB chu k 4, c khi lng nguyn t 55,847

Cu hnh electron: 1s22s22p63s23p63d64s2

St l kim loi mu trng xm, d rn, d dt mng, v gia cng c hc.

Trong t nhin st c 4 ng v bn 54Fe, 56Fe (91,68%), 57Fe, 58Fe.

Nhit nng chy ca st l 15360C, nhit si 28800C, t khi 7,91 g/cm3.

St c tnh dn in, dn nhit tt (km ng v nhm). Di 8000C st c tnh

nhim t, b nam chm ht v tr thnh nam chm (tm thi).

St c 4 dng th hnh (l dng , , , ) mi dng bn nhng nhit nht

nh.

St l kim loi c tch ra t cc m qung st, v rt kh tm thy n dng t

do. thu c st t do, cc tp cht phi c loi b bng phng php kh ha

hc. St c s dng trong sn xut gang v thp, y l cc hp kim, l s ha tan

ca cc kim loi khc (v mt s kim hay phi kim, c bit l cacbon)

1.1.1.2. Tnh cht ha hc

St l cht c hot tnh ha hc trung bnh. iu kin bnh thng nu khng c

hi m, nhng nguyn t h st khng phn ng r rt vi kim in hnh nh O, S,

Cl, Br v n c mng bo v. Nhng khi un nng, phn ng xy ra mnh lit, nht l

khi kim loi trng thi chia nh, nguyn nhn l tng b mt tip xc rt ln gia cc

ht kim loi vi khng kh v s sai lch mng li tinh th ca ht so vi cu trc bn

ca kim loi.



Khi un nng trong khng kh kh st to nn Fe2O3 v nhit cao hn to

nn Fe3O4.

3Fe + 2O2 = Fe3O4

Kh Cl2 phn ng rt d dng vi Fe to thnh FeCl3 l cht d bay hi to nn

khng to c mng bo v.

2Fe + 3Cl = 2FeCl3

Fe tc dng vi S khi un nng nh to nn hp cht khng hp thc FeS.

Fe tan d trong dung dch axit khng c tnh oxi ha gii phng kh H2. Axit

sulfuric c v axit nitric c khng tc dng khng tc dng vi Fe m cn th ng

ha khi ngui, v vy ngi ta vn chuyn nhng axit ny trong cc xitec bng thp.

St ha tan trong axit H2SO4 long.

Fe + H2SO4 = FeSO4

Trong dung dch H2SO4 c nng st b oxy ha n Fe (III).

2Fe + 6H2SO4 = Fe2(SO)3 + 3SO2 + H2O

Fe tinh khit bn i vi khng kh v nc, ngc li st c ln tp cht b n

mn di tc dng ng thi ca hi m, kh CO2 v kh O2 trong khng kh to nn

r st.

2Fe + 3/2O2 + nH2O = Fe2O3.nH2O

R st c to nn trn b mt l mt lp xp v gin khng bo v c st

khi tip tc tc dng v qu trnh n mn st tip tc xy ra.

Fe bn vi kim trng thi dung dch v nng chy v oxit ca n hu nh

khng th hin tnh lng tnh.

1.1.2. Ngun gc xut hin ca st trong nc

Ngun gc xut hin st trong nc c th do ngun gc t nhin hoc do nhn

to.

S xut hin st trong nc do t nhin nh nhng m khong vt ca st, st

c phn tn trong nc c th do ma, tuyt tan, nc ma ri xung mt t,

ng ph, khu cng nghip ko theo kim loi st xung h, sng



St c trong thin nhin di dng hp cht oxit, sunfua, cacbonat v silicat.

S xut hin st trong nc c th do nhn to do cc ngun nc thi, x nc

thi sinh hot, sn xut cng nghip thi ra nhiu loi bi kim loi, trong c st

khng nhng gy nhim mi trng khng kh, t m cn gy nhim mi trng

nc.

1.1.3. Vai tr ca st [6]

St l kim loi c s dng nhiu nht, chim khong 95% tng khi lng kim

loi sn xut trn ton th gii. S kt hp ca gi thnh thp v cc c tnh tt v

chu lc, do, cng lm cho n tr thnh mt trong nhng nguyn vt liu khng

th thay th c, c bit trong cc ng dng nh sn xut t, thn tu thy ln, cc

b khung cho cc cng trnh xy dng. Thp l hp kim ni ting nht ca st, ngoi ra

cn c mt s hnh thc tn ti khc ca st nh:

Oxit st (III) c s dng sn xut cc b lu t tnh trong my tnh. Chng

thng c trn ln vi cc hp cht khc, v bo tn thuc tnh t trong hn hp

ny.

St l cht xc tc hnh thnh nn dip lc v hot ng nh cht mang oxy.

St c vai tr rt cn thit i vi mi c th sng, ngoi tr mt s vi khun. N

ch yu lin kt n nh bn trong cc protein kim loi, v trong dng t do n sinh ra

cc gc t do ni chung l c vi cc t bo. Ni rng st t do khng c ngha l n

t do di chuyn trong cc cht lng trong c th. St lin kt cht ch vi mi phn t

sinh hc v th n s gn vi cc mng t bo, axit nucleic, protein

Trong c th ng vt st lin kt trong cc t hp heme (l thnh phn thit yu

ca cytochromes), l nhng protein tham gia vo cc phn ng oxi ha-kh (bao gm

nhng khng gii hn ch l qu trnh h hp) v ca cc protein chuyn ch xy

nh hemoglobin v myoglobin.

St v c tham gia trong cc phn ng oxi ha-kh cng c tm thy trong cc

cm st-lu hunh ca nhiu enzyme, chng hn nh cc enzyme nitrogenase (tham

gia qu trnh tng hp ammoniac t nitow v hydro) v hydrogenase. Tp hp cc



protein st phi-heme c trch nhim cho mt dy cc chc nng trong mt s loi hnh

c th sng, chng hn nh cc enzyme metan monoxygenase (oxi ha metan thnh

metalnol), ribonucleotidequ reductase (kh ribose thnh deoxyribose; tng hp sinh

hc DNA), hemerythrins (vn chuyn oxy v ngng kt trong c ng vt khng

xng sng bin) v axit phosphates ta (thy phn cc este photphat). Khi c th

chng li s nhim khun, n c ring st trong protein vn chuyn transferring v

th vi khun khng th s dng c st.

1.1.4. Tc hi ca st [1,6]

Vic hp th qu nhiu st gy ng c, v cc st (II) d tha s phn ng vi

cc peroxit trong c th sn xut ra cc gc t do. Khi st trong s lng bnh

thng th c th c mt c ch chng xi ha c th kim sot qu trnh ny. Khi

d tha st th nhng lng d tha khng th kim sot ca cc gc t do c sinh

ra.

Mt lng gy cht ngi ca st i vi tr 2 tui l ba gam st. Mt gam c th

sinh ra s ng c nguy him. Danh mc ca DRI v mc chp nhn cao nht v st

i vi ngi ln l 45 mg/ngy. i vi tr em di 14 tui mc cao nht l 40

mg/ngy.

Nu st qu nhiu trong c th (cha n mc gy cht ngi) th mt lot cc

hi chng ri lon qu ti st c th pht sinh, chng hn nh hemochromatosis.

Khi thiu st th hm lng hemoglobin b gim lm cho lng oxi ti cc t bo

cng gim theo, con ngi b mc chng bnh thiu mu do thiu ht st.

1.2. Cc phng php xc nh vi lng st

1.2.1. Phng php quang ph hp th nguyn t (AAS) [2]

Phng php phn tch da trn c s o ph hp th nguyn t ca mt nguyn

t c gi l php o ph hp th nguyn t (php o AAS)

Khi nguyn t tn ti t do th kh v trng thi nng lng c bn, th

nguyn t khng thu hay khng pht ra nng lng. Tc l nguyn t trng thi c

bn. Song nu nguyn t ang tn ti trng thi ny m chng ta kch thch n bng



mt chm tia sng n sc c nng lng ph hp, c di sng trng vi cc vch

ph pht x c trng ca nguyn t , th chng s hp th cc tia sng sinh ra

mt loi ph ca nguyn t. Ph ny c gi l ph hp th ca nguyn t.

Phng php ny c th phn tch c lng vt ca hu ht cc kim loi v c

nhng hp cht hu c hay anion khng c ph hp th nguyn t. Do n c s

dng rng ri trong cc nghnh: a cht, cng nghip ho hc, ho du, y hc, sinh

ho, cng nghip dc phm, nng nghip v thc phm

1.2.2. Phng php quang ph pht x nguyn t (AES) [2]

Khi iu kin thng, nguyn t khng thu hay pht ra nng lng nhng nu

b kch thch th cc in t ho tr s nhn nng lng chuyn ln trng thi c nng

lng cao hn (trng thi kch thch). Trng thi ny khng bn, chng c xu hng

gii phng nng lng tr v trng thi ban u bn vng di dng cc bc x.

Cc bc x ny c gi l ph pht x ca nguyn t.

Phng php AES da trn s xut hin ph pht x ca nguyn t t do ca

nguyn t phn tch trng thi kh khi c s tng tc vi ngun nng lng ph hp.

Hin nay, ngi ta dng mt s ngun nng lng kch thch ph AES nh ngn la

n kh, h quang in, tia la in, plasma cao tn cm ng (ICP)

Nhn chung, phng php AES t nhy rt cao (thng t n.10-3 n n.10-

4%), li tn t mu, c th phn tch ng thi nhiu nguyn t trong cng mt mu. V

vy, y l phng php dng kim tra nh gi ho cht, nguyn liu tinh khit,

phn tch lng vt ion kim loi c trong nc, lng thc, thc phm. Tuy nhin,

phng php ny li ch cho bit thnh phn nguyn t trong mu m khng ch ra

c trng thi lin kt ca n trong mu.

1.2.3. Phng php quang ph hp th phn t UV-VIS [2]

Phng php quang ph hp th phn t hay cn gi l phng php o quang,

phng php phn tch trc quang phn t l mt trong nhng phng php phn tch

cng c thng dng vi rt nhiu th h my khc nhau, t cc my n gin ca th

h trc cn gi l cc my so mu n cc my hin i c t ng ha hin nay,



gi l my quang ph hp th phn t UV-VIS. Cc my o quang lm vic trong vng

t ngoi (UV) v kh kin (VIS) t 190 nm n khong 900 nm.

iu kin thng, cc phn t, nhm phn t ca cht bn vng v ngho nng

lng. y l trng thi c bn. Nhng khi c mt chm sng vi nng lng thch

hp chiu vo th cc in t ho tr trong cc lin kt (, , n) s hp th nng lng

chm sng, chuyn ln trng thi kch thch vi nng lng cao hn. Hiu s gia hai

mc nng lng (c bn E0 v kch thch Em) chnh l nng lng m phn t hp th

t ngun sng to ra ph hp th phn t ca cht.

* Nguyn tc:

Phng php xc nh da trn vic o hp th nh sng ca mt dung dch

phc to thnh gia ion cn xc nh vi mt thuc th v c hay hu c trong mi

trng thch hp khi c chiu bi chm sng. Phng php nh lng php o:

A = K.C

Trong : A: hp th quang

K: hng s thc nghim

C: nng nguyn t phn tch

Phng php ny cho php xc nh nng cht khong 10-5 - 10-7M v l

mt trong cc phng php c s dng kh ph bin.

Phng php trc quang c nhy, n nh v chnh xc kh cao, c s

dng nhiu trong phn tch vi lng. Tuy nhin vi vic xc nh Cd, Pb th li gp rt

nhiu kh khn do nh hng ca mt s ion kim loi tng t. Khi phi thc hin

cc cng on che, tch phc tp.

1.3. Phng php quang ph hp th phn t UV-VIS

1.3.1. Gii thiu phng php quang ph hp th phn t UV-VIS [2]

L phng php phn tch da trn s so snh cng mu ca dung dch

nghin cu vi cng mu ca dung dch tiu chun c nng xc nh



1.3.1.1. S hp th nh sng ca dung dch mu

Dung dch c mu l do bn thn dung dch hp th mt phn quang ph (mt

vng quang ph) ca nh sng trng, phn cn li l ra cho ta mu ca dung dch,

chnh l mu ca phn nh sng trng b hp th.

Dung dch c mu xc nh th hp th bc sng n sc tng ng v th hin

qua:

Hnh 1.1. Dy mu ca nh sng trng

Bng 1.1. S hp th mu ca dung dch mu

TIA SNG N SC B HP TH MU CA DUNG DCH

400nm 450nm : vng tm Lc nh vng

450nm 480nm : vng chm Vng

480nm 490nm : vng chm lc Da cam

490nm 510nm : vng lc chm

510nm 560nm : vng lc ta

560nm 575nm :vng lc nh vng Tm

575nm 590nm : vng vng Chm

590nm 640nm : vng da cam Chm lc

640nm 720nm : vng Lc chm

720nm 800nm : vng ta Lc



S hp th bc x n sc cng mnh (mu cng m) khi dung dch c nng

cng ln.

S hp th ca dung dch theo mu v s ph thuc ca n vo nng ca cht

hp th chnh l c s ca phng php quang ph hp th phn t UV-VIS.

1.3.1.2. Cc nh lut c bn v s hp th nh sng

*nh lut Bug-Lamber (nh lut 1 ca hp th nh sng):

Lng tng i ca chm nh sng b hp th bi mi trng m n i qua

khng ph thuc vo nng ca tia ti. Mi mt lp b dy nh nhau hp th mt

phn dng sng n sc i qua dung dch nh nhau.

Biu thc:

I=I0.e-kl

Trong k: h s hp th

l: b dy ca lp vt cht

* nh lut Lamber-Beer:

Vi b dy ca lp dung dch, h s hp th K t l vi nng ca cht hp th

ca dung dch.

Biu thc:

I=I0.e-*cl

Vi C: Nng dung dch (mol/l)

l: B dy ca cuvet ng dung dch (cm)

: H s hp th phn t

1.3.1.3. Cc i lng hay s dng

truyn quang T(%): l t l gia cng chm sng n sc I sau khi i qua

dung dch vi cng chm sng n sc I0 chiu vo.

T=I/I0= 10-.l.c

* Mt quang D hay hp th A hay tt E

I

ITEAD 0lglg



Khi v l khng i: D = A = K.C

Nguyn tc chung ca phng php o quang xc nh mt cht X:

- Chuyn X thnh mt cht c kh nng hp th nh sng.

- o s hp th nh sng ca X.

- Suy ra hm lng cht cn xc nh.

1.3.1.4. Tnh cht ca mt quang v ng dng trong ha phn tch

-Mt quang c tnh cng tnh:

Trong dung dch c nhiu cht tan hp th bc x nh sng th mt quang o

c chnh l tng cc mt quang ca cc cht c trong dung dch.

-ng dng trong ha phn tch:

o c mt quang ca cht cn phn tch X

- D0: Mt quang ca dung dch trng (dung dch so snh)

Vi Dx = K.Cx

Dung dch trng (dung dch so snh) l dung dch cha tt c cc thnh

phn trong dung dch phn tch tr cht phn tch.

o mt quang ca 1 dy dung dch c nng khc nhau bng mt

cuvet ti mt bc sng nht nh.

(l, = const) th ng biu din D = f(C) s l mt ng thng.



Hnh 1.2. th tuyn tnh gia D v C

1.3.2. Cc iu kin ti u ca php o quang [2]

1.3.3. Cc phng php phn tch nh lng s dng phn tch:

1.3.3.1. Phng php ng tiu chun

* Nguyn tc thc hin:

+ Xy dng ng chun: D = f(C) (y = ax)

- Chun b mt dy dung dch chun c nng tng dn: C1, C2, C3,

C4, C5, C6 ca cht chun phn tch.

- Thm lng thuc th, axit v cc iu kin khc nh nhau vo

dy dung dch chun a v dng dung dch mu.

- o mt quang D1, D2, D3, D4, D5, D6 ca dung dch chun ( xc

nh max, khong tuyn tnh).

- V th D = f(C).

+ Chun b dung dch phn tch ging ht vi dy chun.

+ o mt quang ca dung dch phn tch Dx ri da vo th ta

tnh c Cx.

nng

D3

D2

mt quang

C1 C2 C3 C4 C5 C6

D6

D5

D4

D1



Phng php ny c u im l xc nh c hng lot mu. iu kin p dng

ca phng php ny l cc dung dch mu hp ph nh sng tun theo nh lut

Lawmbe Bia.

1.3.3.2. Phng php thm chun

*Nguyn tc thc hin:

- Ly mt lng dung dch phn tch (Cx) vo 2 bnh nh mc 1 v 2.

- Thm vo bnh 2 mt lng dung dch chun ca cht phn tch (Ca).

- Thc hin phn ng hin mu c 2 bnh trong cc iu kin ti u

chn hon ton nh nhau.

- o mt quang ca 2 dung dch bc sng ti u max, khong tuyn

tnh v trong cng cuvet.

Theo nh lut Lm be Bia ta c:

Dx = .l.Cx (dung dch khng thm)

Da = .l. (Cx+Ca) (dung dch c thm)

Do ta tnh c: Cx = Ca

Dng phng php ny ta c th loi tr c nh hng ca cc ion l c trong

dung dch phn tch. Phng php ny cng c dng kim tra ng ca php

xc nh

1.3.3.3. u im ca phng php UV VIS

- C nhy cao, thng c th xc nh lng cc nng nh hn 10-7 M. u

im ny c ngha trong 2 lnh vc:

Trong lnh vc phn tch vt: cho php tin hnh php o nh lng cc vi cu

t ca mu c hm lng c 1 ppm v khi lng.

Trong lnh vc vi phn tch: c th xc nh lng cc cu t chnh trong mu

c kch thc rt nh.

- Thc hin c nhanh hn, thun li hn (so vi phng php chun v

trng lng truyn thng).

- C th tin hnh php phn tch t 5 n 10 mu trong 1 pht.



- Cung cp cc s liu phn tch cho thng bo c bn v cu trc phn t v v

bn cht lin kt ha hc.

1.4. Cc phng php ly v x l mu

1.4.1. Phng php ly mu

Phng php ly mu th ng khng lin tc: mu c ly bng phng php

khuych tn t nhin ti cc b phn thu mu. Ly theo phng nm ngang, ly nc

b mt.

1.4.2. Cc phng php x l mu v bo qun mu

Ngay sau khi ly, axit ha n pH < 2 v bo qun mu trong chai nha, mu bn

trong 1 thng.

1.5. S lc vi nt v ni ly mu

1.5.1. H Thc Gin Vnh Trung

Thng tin c s: V tr a l

Bu Thc Gin-Vnh Trung nm gia hai phng Thc Gin v Vnh Trung,

qun Thanh Kh, Thnh ph Nng.

H Thc Gin:

- Pha ng: Gip vi ng Vn Cao

- Pha Ty: Gip vi ng Tn

- Pha Nam: Gip vi ng Hm Nghi

- Pha Bc: Gip vi ng Tn

H Vnh Trung:

- Pha ng: Gip vi ng Vn Cao

- Pha Ty: Gip vi ng T Ngc Vn

- Pha Nam: Gip vi ng Quang

- Pha Bc: Gip vi ng Hm Nghi



Hnh 1.3. Quang cnh h Thc Gin-Vnh Trung

Dn s v din tch khu vc xung quanh h

H Thc Gin -Vnh Trung nm gia hai phng Thc Gin v Vnh Trung thuc

qun Thanh Kh - TP Nng.

Qun Thanh Kh l qun c mt dn s ng nht thnh ph c:

* Din tch: 9,3km2, chim 0,74% din tch ton thnh ph.

* Dn s: 159.272 ngi, chim 21,17% dn s ton thnh ph.

* Mt dn s: 17.126ngi/km2.

Qun Thanh Kh bao gm 8 phng: Vnh Trung, Tn Chnh, Thc Gin, Chnh

Gin, Tam Thun, Xun H, Thanh Lc n, An Kh. Trong , 2 phng Thc Gin

v Vnh Trung nm v tr trung tm thnh ph l khu trung tm vn ha thng mi

ca qun v thnh ph.

Phng Vnh Trung c:

* Din tch: 0,52km2.

* S dn: 17539 ngi .

* Mt dn s: 33.729 ngi/km2.



Phng Thc Gin c dn s l: 16.098 ngi.

Thng tin v bu Thc Gin Vnh Trung

Ngun gc:

Nguyn gc bu Thc Gin-Vnh Trung l mt ci m c din tch khong 11ha,

do qu trnh th ha nn din tch h b thu hp cn li khong 3ha.

Chc nng:

- iu tit v thot nc ma cho khu vc.

- iu ha vi kh hu.

- To cnh quan cho khu th.

Din tch

Gn 29.649m2.

Chiu di, chiu rng ln nht

H s 2:

Chiu di: gn 200m.

Chiu rng: khong 80m.

H s 1:

Chiu di: gn 158m.

Chiu rng: khong 125m.

su ln nht:

Bu Vnh Trung: 3.25m.

Bu Thc Gin: 4.03m.

Dung tch:

T 40.000 52.000m3, vo ma ma c th cha c hn 65000m3 nc.



Hnh 1.4. Bn h Thc Gin Vnh trung

Hnh 1.5. Bn h Thc Gin Vnh trung



1.5.2. Sng Ph Lc

Sng Ph Lc bt ngun t thn Khnh Sn (Ha Khnh Nam, Lin Chiu,

Nng) chy qua cc phng Ha Minh, Thanh Lc n v ra vnh Nng thng

qua ca sng nm trn ng Nguyn Tt Thnh thuc P. Thanh Kh ng (Thanh

Kh).

1.5.3. Nh my thp [5]

Nh my thp Thi Bnh Dng, L C10-C19 Cm Cng Nghip Thanh Vinh m

rng, Huyn Ho Vang, Thnh ph Nng.

1.6. Chun b mu phn tch [4]

Ly lng nc cn phn tch cho vo bnh nh mc 50ml, thm vo 1ml dung

dch HCl long, c n th tch cn khong 40ml. Lm ngui, nu dung dch c th

phi lc.Thm 1ml dung dch hydroxylamine kh Fe3+ thnh Fe2+, ri thm 1ml

dung dch o-phenantrolin. Nh tng git dung dch ammoniac n khi PH khong bng

4(s dng my o pH). nh mc bng nc ct, lc u. o mt quang ca dung

dch so vi mu trng.



CHNG 2: THC NGHIM V PHNG PHP NGHIN CU

2.1. Dng c, thit b, ha cht

2.1.1. Dng c

- My quang ph hp th phn t. .

- Cn phn tch, cn k thut.

- Bp in, t ht, t sy.

- Bnh nh mc cc loi.

- Pipet cc loi.

- Cc thy tinh, a thy tinh, ng ong

- L ng mu.

- Mt knh ng h.

2.1.2. Thit b

S khi tng qut ca 1 thit b o quang nh sau:

1. Ngun bc x lin tc

2. B phn to tia n sc

3. Cuvet ng dung dch

4. tect

5. Ch th kt qu

2

3

1

5

4



Hnh 2.1. My phn tch UV-VIS Hnh 2.2. Cuvet

-Ngun bc x: c hai loi ngun

+Vng kh kin: dng n Vonfram W-Lamp

+Vng t ngoi: dng n Hidro hoc n teri D-Lamp

- Cc ngun to bc x n sc: lm nhim v phn ly bc x thnh bc x n

sc c di sng khc nhau.

C 2 loi:

+My to bc x n sc bng lng knh

Hnh 2.3. Lng knh hp th quang ph

+My to bc x n sc bng cch t.

+Vng kh kin: dng cuvet thy tinh.



+Vng t ngoi: dng cuvet thch anh.

- tect: l cc t bo quang in vi hiu ng quang in ngoi hoc cc nhn

quang in c nhim v bin i nng lng bc x thnh tn hiu in.

2.1.3. Ha cht

Ha cht tkpt gm :

- HCl, NH2OH.HCl.

- O-phenantrolin.

- Amoniac.

- Dung dch chun phn st amoni.

2.2. Pha cc loi dung dch

Pha ch dung dch chun Fe

Dung dch chun Fe3+ 100ppm c pha nh sau: Ha tan 0,8634g

NH4Fe(SO4)2.12H2O trong nc ct, thm 2ml HCl c, nh mc thnh 1 lt bng

nc ct.

Pha thuc th o-phenantrolin: ly 0,28 g o-phenantrolin trong nc ct thnh

100ml,(nh 1-2 git HCl, un cch thy) ng dung dch trong bnh nu v ch

mt.

Hydroxylamin 10%: Ha tan 10g hydroxylamine clohydric, nh mc bng nc

ct thnh 100ml.

Dung dch HCl 1:9: Pha 10ml HCl c vo 90 ml nc ct.

Pha ch cc dung dch nh hng

-Dung dch chun Cu2+ 100ppm: Ly 0,3906g CuSO4.5H2O ha tan vi mt t

nc ct c pha 1ml H2SO4 1:5 v nh mc thnh 1 lt bng nc ct.

- Dung dch chun Co2+ 1000ppm: Ly 3,1017g Co(NO3)2 ha tan bng nc ct

v nh mc thnh 1 lt.

- Dung dch chun Ni2+ 50ppm: Ly 4,9530g NiSO4.6H2O pha trong 200ml HNO3

35% ri nh mc ln 1 lt bng nc ct.



- Dung dch chun Zn2+ 500ppm: Ly 1,1039g ZnSO4.7H2O ha tan bng nc

ct v nh mc ln 500ml.

- Dung dch chun Cr3+ 1000ppm: Ly 7,6923g Cr2(NO3)3.9H2O ho tan vo

nc ct v nh mc thnh 1 lt.

2.3. Nhng vn cn nghin cu

- Tm thuc th thch hp, nghin cu cc yu t nh hng n qu trnh xc

nh st trong nc v loi tr cc yu t nh hng.

- Kho st bn mu ca phc theo thi gian.

- Xc nh gii hn nng pht hin ca st trong nc thi bng php trc

quang phn t UV-VIS.

- Xc nh khong nng tuyn tnh ca st.

- Xc nh hiu sut thu hi ca phng php.

- nh gi sai s thng k ca phng php.

2.4. Thc hin nghin cu iu kin ti u phn tch hm lng st trong nc

bng phng php quang ph hp th phn t UV-VIS.

Da trn mt s qu trnh phn tch st trong nc tin hnh nghin cu mt s

iu kin ca qu trnh phn tch sao cho ph hp vi diu kin phng th nghim

nhm t c hiu qu cao nht. iu kin ti u c nghin cu theo phng php

n bin, thay i cc yu t cn kho st, bin i dn sao cho hiu sut t cao nht.

2.4.1. Chn thuc th thch hp

Thuc th thng dung trong vic phn tch hm lng st bng phng php

trc quang phn t gm c: thuc th tioxianat, axit sufuxalixilic v o-phenantrolin.

Trong iu kin cho php ca phng th nghim chng ti nghin cu s to phc mu

ca Fe2+ vi thuc th o-phenantrolin.

2.4.2. Kho st bn mu ca phc Fe2+ v thuc th theo thi gian

Chun b mu bit trc nng st (ly 50ml nc c nng st l

0,001mg/ml), thm vo 1ml dung dch HCl long, c n th tch cn khong 40ml.

Lm ngui, nu dung dch c th phi lc. Thm 1ml dung dch hydroxylamine



kh Fe3+ thnh Fe2+, ri thm 1ml dung dch o-phenantrolin. Nh tng git dung dch

ammoniac n khi pH khong bng 4 (s dng my o pH), sau nh mc bng

nc ct n 50ml, lc u. Tin hnh o mt quang ca mu trong nhng khong

thi gian khc nhau da vo ng chun xc nh hm lng st trong cc mu, t kt

qu o c ta rt ra c bn mu ca phc Fe2+ theo thi gian i vi php xc

nh st bng thuc th o-phenantrolin.

2.4.3. Kho st nh hng ca pH

Chun b 7 mu c cng nng st (ly 50ml nc c nng 0,001mg/ml),

thm vo cc mu 1ml dung dch HCl long, c n th tch cn khong 40ml. Lm

ngui, nu dung dch c th phi lc. Thm 1ml dung dch hydroxylamine kh Fe3+

thnh Fe2+, ri thm 1ml dung dch o-phenantrolin. Nh tng git dung dch ammoniac

sao cho cc mu c pH t 39 (s dng giy my o pH), sau nh mc bng nc

ct n 50ml, lc u, n nh 10 pht. Sau tin hnh o mt quang ca dy

da vo ng chun xc nh hm lng st trong cc mu. Rt ra kt lun v s nh

hng pH i vi php xc nh st bng thuc th o-phenantrolin

2.4.4. Kho st gii hn pht hin ca Fe2+

Tin hnh pha mu cha dung dch Fe2+ c nng gim dn, iu kin ch ha

tng t nhau. Cch tin hnh phn tch: Ly 50ml mu ,thm vo 1ml dung dch HCl

long, c n th tch cn khong 40ml. Lm ngui, nu dung dch c th phi lc.

Thm 1ml dung dch hydroxylamine kh Fe3+ thnh Fe2+, ri thm 1ml dung dch o-

phenantrolin. Nh tng git dung dch ammoniac n khi pH khong bng 4 (s dng

my o pH), sau nh mc bng nc ct n 50ml, lc u, n nh 10 pht.

Tin hnh o mt quang trn my UV-VIS tm nng ca Fe2+ m ti vn

cn pht hin c.

2.4.5. Kho st gii hn nng tuyn tnh

Trong phng php trc quang phn t UV-VIS th s ph thuc ca mt

quang D o c i vi nng ca cht phn tch ch tuyn tnh trong mt khong



nng nht nh. Do cn phi tin hnh kho st khong nng tuyn tnh ca

st m bo cho mc chnh xc ca php o.

Tin hnh pha dung dch chun Fe2+ 1000ppm. Chun b dy dung dch o vi

nng Fe2+ tng dn, ch ha cc mu dung dch ny nh sau:

Ly 50 ml mu, thm vo 1ml dung dch HCl long, c n th tch cn khong

40ml. Lm ngui, nu dung dch c th phi lc. Thm 1ml dung dch hydroxylamine

kh Fe3+ thnh Fe2+, ri thm 1ml dung dch o-phenantrolin. Nh tng git dung

dch ammoniac n khi pH khong bng 4 (s dng my o pH), sau nh mc bng

nc ct n 50ml, lc u, n nh 10 pht. Sau o mt m ti s ph

thuc ca mt quang D vo nng C l tuyn tnh nht.

2.4.6. Lp ng chun xc nh st

Tin hnh lp ng chun nh sau: chun b 6 bnh nh mc loi 50ml, ly ln

lt vo mi bnh 0; 0,5; 1,0; 2,0; 5,0; 10,0ml dung dch st chun c nng

0,005mg/ml. Thm vo mi bnh 1ml HCl long ri nh mc ln 50 ml bng nc ct,

chuyn sang 6 cc c nh th t, sau c n th tch cn khong 40ml, lm ngui,

nu dung dch c th phi lc. Thm 1ml dung dch hydroxyamin, thm 1ml dung dch

thuc th o-phenantrolin, nh tng git ammoniac c n khi pH khong bng 4 (s

dng my o pH), sau nh mc bng nc ct n 50ml, lc u, n nh 10

pht. Tin hnh o mt quang ca dung dch so vi mu trng.

2.4.7. Kho st cc yu t nh hng

2.4.7.1. Kho st nh hng ca Cu2+

i vi xc nh Fe2+

Chun b 6 mu c cng nng st bit trc trong iu kin ch ha tng

t nh khi lp ng ca chun, trong hm lng Cu2+ tng dn. Tin hnh o mt

quang ca dy da vo ng chun xc nh hm lng st trong cc mu. Rt ra

kt lun v s nh hng Cu2+ i vi php xc nh st bng thuc th o-

phenantrolin.



2.4.7.2. Kho st nh hng ca Co2+ i vi xc nh Fe2+


t nh khi lp ng ca chun, trong hm lng Co2+ tng dn. Tin hnh o mt


kt lun v s nh hng Co2+ i vi php xc nh st bng thuc th o-

phenantrolin.

2.4.7.3. Kho st nh hng ca Ni2+ i vi xc nh Fe2+


t nh khi lp ng ca chun, trong hm lng Ni2+ tng dn. Tin hnh o mt


kt lun v s nh hng Ni2+ i vi php xc nh st bng thuc th o-phenantrolin.

2.4.7.4. Kho st nh hng ca Zn2+ i vi xc nh Fe2+


t nh khi lp ng ca chun, trong hm lng Zn2+ tng dn. Tin hnh o mt


kt lun v s nh hng Zn2+ i vi php xc nh st bng thuc th o-phenantrolin

2.4.7.5. Kho st nh hng ca Cr3+ i vi xc nh Fe2+


t nh khi lp ng ca chun, trong hm lng Cr3+ tng dn. Tin hnh o mt


kt lun v s nh hng Cr3+ i vi php xc nh st bng thuc th o-phenantrolin.

2.4.8. Phng php loi tr cc yu t nh hng

Cc cht oxi ha mnh: C th loi tr bng cch thm d cht kh hydroxyamin.

Xyanua, nitrit, photphat (polyphotphat nh hng nhiu hn octophotphat): loi

tr bng cch un si vi axit.

Cc ion kim loi crom, km (khi nng ca chng gp 10 ln nng st)

coban, ng (khi nng chng gp 5 ln st) niken (khi nng ca n gp 2 ln

nng st) bimut, cadimi, thy ngn molydat to kt ta vi o-phenatrolin. Loi tr



bng cch thm d o-phenantrolin, trong vn khng loi tr c nh hng ca

cc ion kim loi th phi s dng n phng php chit tch kim loi gy cn tr.

2.5. Chun b mu gi

Mu gi l mu bit trc c nng st, ly 50ml nc ct, thm vo

0,5ml dung dch Fe3+ tiu chun 0,1mg/ml. C nng 0,001mg/ml.

2.6. nh gi hiu sut thu hi

Da vo cc iu kin ti u kho st trn, chng ti tin hnh o mt

quang trn mu gi tnh s sai lch gia kt qu o c bng my vi kt qu thc t.

Lm 6 ln ly gi tr trung bnh.

2.7. nh gi sai s thng k ca phng php

Trong phn tch vic nh gi cc kt qu l mt trong cc bc khng th thiu

c ca cc qu trnh phn tch. Trong bc ny vic tnh ton sai s l quan trng

nht v n cho ta bit kt qu phn tch thu c ng v chnh xc ti mc no.

kim tra lp ca phng php ti phng th nghim ta lm nh sau: o

cng mt mu phn tch 6 ln, sau tm lch chun ca phng php. lch

chun ca phng php cng nh th lp ca phng php cng cao.

2.8. Quy trnh phn tch

Ly lng nc cn phn tch cho vo bnh nh mc 50ml, thm vo 1ml dung

dch HCl long, c n th tch cn khong 40ml. Lm ngui, nu dung dch c th

phi lc. Thm 1ml dung dch hydroxylamine kh Fe3+ thnh Fe2+, ri thm 1ml

dung dch o-phenantrolin. Nh tng git dung dch ammoniac n khi pH khong bng

4 (s dng my o pH), sau nh mc bng nc ct n 50ml, lc u, n nh

10 pht. Tin hnh o mt quang ca dung dich so vi mu trng.

2.9. Phn tch mu thc t

2.9.1. Ly v chun b mu

Mu c ly ti cc v tr khc nhau trong h, thi gian ly mu l 2 ln, sng v

chiu, mu c axit ha n pH



2.9.2. Phn tch mu [4]

Mu thc t sau khi c ly v a v phng th nghim bo qun.Ta tin hnh

phn tch nh sau:

Ly lng nc mu thc t cn phn tch cho vo bnh nh mc 50ml, thm

vo 1ml dung dch HCl long, c n th tch cn khong 40ml. Lm ngui, nu dung

dch c th phi lc. Thm 1ml dung dch hydroxylamine kh Fe3+ thnh Fe2+, ri

thm 1ml dung dch o-phenantrolin. Nh tng git dung dch ammoniac n khi pH

khong bng 4 (s dng my o pH), sau nh mc bng nc ct n 50ml, lc

u, n nh 10 pht. Tin hnh o mt quang ca dung dich so vi mu trng.



CHNG 3: KT QU V BN LUN

3.1. Kt qu kho st xc nh st

3.1.1. Kt qu kho st bn mu ca phc Fe2+ v thuc th theo thi gian

Bng 3.1. S ph thuc ca mt quang D theo thi gian.(nng st

0,001mg/ml, pH=4)

Thi gian o(pht) 0 5 10 15 20 25 30

D 0,2179 0,2186 0,2326 0,2329 0,2356 0,2305 0,2335

Hnh3.1. S ph thuc ca mt quang D ca phc to bi st (II) v thuc th

o-phenantrolin theo thi gian.

Da vo s liu c th nhn thy rng dung dch c bn mu t 10 pht tr

ln. Do chng ta nn tin hnh o mt quang sau khi to phc mu khong 10

pht dung dch mu n nh.



3.1.2. Kt qu kho st nh hng ca pH

Bng 3.2. Bng kt qu kho st nh hng ca pH.(nng st 0,001mg/ml,o

sau khi to phc 10 pht)

Hnh 3.2. th biu din s nh hng ca pH i vi vic xc nh st trong

nc.

Da vo kt qu kho st c c th thy rng trong khong pH 39 th mt

quang o c cao nht pH=4.

3.1.3. Kt qu kho st gii hn pht hin ca Fe2+

Kt qu kho st nhy i vi php xc nh st bng phng php trc quang

phn t dng thuc th o-phenantrolin:

Dung dch o trong mi bnh: Dung dch Fe2+ 5.10- 4 mg/ml (nng gim dn),

trong iu kin ch ha tng t nh khi lp ng ca chun, trong hm lng.

Tin hnh o mt quang.

Kt qu: Gii hn nng pht hin st l 3.10-6 (mg/ml).

pH 3 4 5 6 7 8 9

D 0,2031 0,2109 0,2045 0,1854 0,1886 0,1938 0,1976



3.1.4 Kt qu kho st khong nng tuyn tnh

Bng 3.3. Bng kt qu kho st khong nng tuyn tnh Fe2+

Nng Fe3+ (mg/ml) D

0 0,0003

1.10-5

0,0082

2.10-5

0,0098

5.10-5

0,0176

1.10-4

0,0218

2.10-4

0,0411

5.10-4

0,0983

1.10-3

0,2084

2.10-3

0,3583

4.10-3

0,6083

Hnh 3.3. th biu din nng tuyn tnh i vi xc nh Fe2+

Da vo kt qu kho st c ta rt ra nhn xt: Khong nng thch hp

tin hnh php o l t khong 1.10-5 n 4.10-3 (mg/ml).



3.2. Kt qu xy dng ng chun

Bng 3.4. Bng kt qu lp ng chun ca Fe2+(pH=4,o quang sau 10 pht)

Nng Fe3+ (mg/ml) 0 0,00005 0,0001 0,0002 0,005 0,001

D 0 0,0125 0,0219 0,051 0,1109 0,2076

Hnh 3.4. ng chun ca php xc nh st bng thuc th o-phenantrolin

3.3. Kt qu kho st cc yu t nh hng

3.3.1.Kt qu kho st nh hng ca Cu2+ i vi xc nh Fe2+

Bng 3.5. Bng kt qu kho st nh hng ca Cu2+ i vi xc nh Fe2+

STT Nng Fe3+

chun (mg/ml)

Nng Cu2+

(mg/ml)

D

Nng Fe3+ o

c (mg/ml)

Sai s

tuyt i

(%)

1 0,001

0 0,2096

1,0010.10-3

0,100

2 0,001

0,0002

0,2084

9,9500.10-4

0,400

3 0,001

0,0004

0,2116

1,0110.10-3

1,010

4 0,001

0,0010

0,2122

1,0130.10-3

1,300

5 0,001

0,0020

0,2093

9,9950.10-4

0,050

6 0,001

0,0040

0,2108

1,0067.10-3

0,670



Hnh 3.5. th biu din s nh hng ca Cu2+ i vi xc nh Fe2+.

Da vo kt qu kho st c ta thy rng Cu2+ nh hng khng ng k n

vic xc nh st trong nc bng phng php trc quang phn t UV-VIS bng thuc

th o-phenantrolin.

3.3.2. Kt qu kho st nh hng ca Co2+ i vi xc nh Fe2+

Bng 3.6. Bng kt qu kho st nh hng ca Co2+ i vi xc nh Fe2+

STT Nng Fe3+

chun (mg/ml)

Nng Co2+

(mg/ml) D

Nng Fe2+ o

c (mg/ml)

Sai s tuyt

i (%)

1 0,001

0 0,2156

1,0298.10-3

2,980

2 0,001

0,0002

0,2150

1,0269.10-3

2,690

3 0,001

0,0004

0,2075 9,9088.10

-4 0,912

4 0,001

0,0010

0,2104

1,0048.10-3

0,480

5 0,001

0,0020

0,2124 1,0144. 10-3

1,440

6 0,001

0,0040

0,2155 1,0293. 10-3

2,930



Hnh 3.6. th biu din s nh hng ca Co2+ i vi xc nh Fe2+

Da vo kt qu kho st c ta thy rng Co2+ nh hng khng ng k n


th o-phenantrolin.

3.3.3. Kt qu kho st nh hng ca Ni2+ i vi xc nh Fe2+

Bng 3.7. Bng kt qu kho st nh hng ca Ni2+ i vi xc nh Fe2+

STT Nng Fe3+

chun (mg/ml)

Nng Ni2+

(mg/ml) D

Nng Fe2+

o c

(mg/ml)

Sai s tuyt

i (%)

1 0,001

0 0,2146 1,0250. 10-3

2,500

2 0,001

0,00025

0,2134 1,0192. 10-3

1,920

3 0,001

0,00050

0,2105 1,0053. 10-3

0,530

4 0,001

0,00100

0,2128 1,0163.10-3

1,630

5 0,001

0,00200

0,2057 9,8225.10-4

1,780

6 0,001

0,00400

0,2087 9,9664.10-4

0,336



Hnh 3.7. th biu din s nh hng ca Ni2+ i vi xc nh Fe2+

Da vo kt qu kho st c ta thy rng Ni2+ khng nh hng n vic xc

nh st trong nc bng phng php trc quang phn t UV-VIS bng thuc th o-

phenantrolin.

3.3.4. Kt qu kho st nh hng ca Zn2+ i vi xc nh Fe2+

Bng 3.8. Bng kt qu kho st nh hng ca Zn2+ i vi xc nh Fe2+

STT Nng Fe3+

chun (mg/ml)

Nng Zn2+

(mg/ml) D

Nng Fe2+

o c

(mg/ml)

Sai s tuyt

i (%)

1 0,001

0 0,2120 1,0125.10-3

1,250

2 0,001

0,00025

0,2150 1,0269.10-3

2,690

3 0,001

0,00050

0,2116 1,0106.10-3

1,060

4 0,001

0,00100

0,2077 9,9184.10-4

0,816

5 0,001

0,00200

0,2060 9,8369.10-4

1,631

6 0,001

0,00400

0,2057 9,8225.10-4

1,775



Hnh 3.8. th biu din s nh hng ca Zn2+ i vi xc nh Fe2+

Da vo kt qu kho st c ta thy rng Zn2+ nh hng khng ng k n


th o-phenantrolin.

3.3.5. Kt qu kho st nh hng ca Cr3+ i vi xc nh Fe2+

Bng 3.9. Bng kt qu kho st nh hng ca Cr3+ i vi xc nh Fe2+

STT Nng Fe3+

chun (mg/ml)

Nng Cr3+

(mg/ml) D

Nng Fe2+

o c

(mg/ml)

Sai s tuyt

i (%)

1 0,001

0 0,2108 1,0067.10-3

0,670

2 0,001

0,0002

0,2016 9,6257.10-4

3,743

3 0,001

0,0004

0,2081 9,9376.10-4

0,624

4 0,001

0,0010

0,2099 1,0024.10-3

0,240

5 0,001

0,0020

0,1995 9,5250.10-4

4,750

6 0,001

0,0040

0,2027 9,6785.10-4

3,215



Hnh 3.9. th biu din s nh hng ca Cr3+ i vi xc nh Fe2+

Da vo kt qu kho st c ta thy rng Cr3+ nh hng khng ng k n


th o-phenantrolin.



3.4. Quy trnh phn tch xc nh hm lng st trong mu nc

Axit ha n pH



Bng 3.10. Hiu sut thu hi ca phng php i vi php xc nh st

Ln o Nng st

thc t (mg/ml) D

Nng st o

c (mg/ml) H(%)

1 0,001

0,1858 8,8676.10-4

88,676

2 0,001

0,1996 9,5298.10-4

95,298

3 0,001

0,1875 8,9491.10-4

89,491

4 0,001

0,2010 9,5969.10-4

95,969

5 0,001

0,1972 9,4146.10-4

94,146

6 0,001

0,1843 8,7956.10-4

87,956

Htrung bnh 91,923

Nh vy hiu sut thu hi trung bnh ca phng php l 91,923 %, p ng yu

cu ca phng php phn tch vt kim loi.

3.6. Kt qu nh gi sai s thng k ca phng php

Bng 3.11. Bng kt qu D nh gi sai s thng k ca phng php

Fe3+

nng 0.05 (mg/ml) Fe3+ nng 0.025 (mg/ml)

0,2076 0,0983

0,1996 0,0926

0,1875 0,0894

0,2010 0,0879

0,1972 0,0934

0,1843 0,1008

nh gi sai s thng k ca phng php cc s liu c ly bng 3.11.



Bng 3.12. Bng kt qu nh gi sai s thng k ca phng php

Cc i lng c trng Fe3+ 0.05 (mg/ml) Fe3+ 0.025 (mg/ml)

Gi tr mt quang trung bnh 0,1962 0,0938

Phng sai S2 7,6572.10-5 2,5004.10-5

lch chun S 8,7505.10-3 5,0004.10-3

H s bin ng Cv 4,4600 5,3309

sai chun Sx 3,5724.10-3

2,0414.10-3

Sai s tin cy 9,1811.10-3 5,2464.10-3

3.7. Kt qu phn tch thc t

3.7.1. Kt qu phn tch mu thc t h Thc Gin Vnh Trung

M1: Mu ly h Thc Gin gip ng Hm Nghi.

M2: Mu ly h Thc Gin gip ng Tn .

M3: Mu ly h Thc Gin gip ng Vn Cao.

M4: Mu ly h Vnh Trung gip ng Hm Nghi

M5: Mu ly h Vnh Trung gip ng Vn Cao.

M6: Mu ly h Vnh Trung gip ng Quang Dng

M7: Mu ly h Vnh Trung gip ng T Ngc Vn.



Bng 3.13. Kt qu phn tch mu thc t ti h Thc Gin-Vnh Trung(thng 3/2012).

Tn mu D Nng st trong mu

(mg/ml)

M1S 0,0146 6,5259.10-5

M2S 0,0147 6,5739.10-5

M3S 0,0260 1,1996.10-4

M4S 0,0128 5,6622.10-5

M5S 0,0144 6,4299.10-5

M6S 0,0153 6,8618.10-5

M7S 0,0170 7,6775.10-5

M1C 0,0150 6,7179.10-5

M2C 0,0145 6,4779.10-5

M3C 0,0240 1,1037.10-4

M4C 0,0137 6,0940.10-5

M5C 0,0169 7,6296.10-5

M6C 0,0143 6,3820.10-5

M7C 0.0192 8,7332.10-5



Bng 3.14. Kt qu phn tch mu thc t ti h Thc Gin - Vnh Trung (thng

4/2012).


(mg/ml)

M1S 0,1159 5,5134.10-4

M2S 0,0931 4,4194.10-4

M3S 0,1092 5,1919.10-4

M4S 0,1140 5,4223.10-4

M5S 0,0870 4,1267.10-4

M6S 0,0818 3,8772.10-4

M7S 0,0917 4,3522.10-4

M1C 0,1025 4,8704.10-4

M2C 0,0935 4,4386.10-4

M3C 0,1042 4,9520.10-4

M4C 0,1140 5,4223.10-4

M5C 0,0893 4,2370.10-4

M6C 0,0834 3,9539.10-4

M7C 0,1007 4,7841.10-4

Mu S l mu ly vo lc 9h

Mu C l mu ly vo lc 16h

Da vo bng s liu ta thy rng tng hm lng st o c t cc mu ly

trong h khng c s chnh lch ln v khng c s thay i khc bit gia cc mu

bui sng v bui chiu.



3.7.2. Kt qu phn tch mu thc t sng Ph Lc

Bng 3.15. Kt qu phn tch mu thc t sng Ph Lc


(mg/ml)

Mth 0,1520 7,2457.10-4

Mtr 0,2845 1,3604.10-3

Mh 0,1437 6,8474.10-4

3.7.3. Kt qu phn tch mu thc t nh my thp

Mu c pha long 2 ln .

Bng 3.16. Kt qu phn tch mu thc t nh my thp


(mg/ml)

Mnmt 0,2004 9,5681.10-4

Vy nng st thc t trong mu l: 1,91362.10-3



CHNG 4: KT LUN V KIN NGH

4.1. Kt lun

Qua mt thi gian nghin cu, trong ti ny chng ti t c mt s kt

qu nh sau:

- kho st c cc iu kin xc nh st (thuc th, mi trng, bn mu

ca phc, nh hng ca cc kim loi khc...).

-Xc nh c gii hn pht hin st bng phng php trc quang phn t,

nh gi c mc chnh xc ca phng php.

- kho st v tm ra iu kin ti u ca qu trnh phn tch tng hm lng st

trong nc bng phng php quang trc phn t UV-VIS vi thuc th o-

phenantrolin.

-Xy dng thnh cng quy trnh phn tch st trong nc s dng thuc th o-

phenantrolin bng phng php trc quang phn t UV-VIS.

-p dng phn tch mt s mu nc ti h Thc Gin Vnh Trung.

4.2. Kin ngh

Tip tc m rng phm vi nghin cu xc nh hm lng ca cc kim loi khc,

c bit l cc kim loi c hi.

Phn tch cc ch tiu khc ca nc, trn c s nh gi mc nhim ca

nc c bin php x l kp thi.



TI LIU THAM KHO

[1]. L Huy B L Th Nh Hoa Phan Kim Phng on Thi Yn-

Nguyn L, c hc mi trng, NXB ai hc Quc gia TP.H Ch Minh

[2].Phm Th H, Cc phng php phn tch quang hc, trng i hc s

phm-i hc Nng (3-2008)

[3]. Hong Nhm, Ha hc v c (tp 3), NXB Gio dc (2000).

[4].T Vng Nghi - Hunh Vn Trung - Trn T Hiu, Phn tch nc, Nh xut

bn khoa hc v k thut.

[5].http://pacificsteel.vn/index.php?option=com_content&view=article&id=1221

&Itemid=639&lang=vi

[6]. http://vi.wikipedia.org/wiki/S%E1%BA%AFt



MC LC

M U ........................................................................................................................ 1

CHNG 1: TNG QUAN TI LIU .......................................................................... 3

1.1. St v d lng ca n trong mi trng .................................................................. 3

1.1.1. Gii thiu v st .................................................................................................... 3

1.1.1.1. Tnh cht vt l .................................................................................................... 3

1.1.1.2. Tnh cht ha hc................................................................................................ 3

1.1.2. Ngun gc xut hin ca st trong nc ................................................................ 4

1.1.3. Vai tr ca st ....................................................................................................... 5

1.1.4. Tc hi ca st ...................................................................................................... 6

1.2. Cc phng php xc nh vi lng st .................................................................... 6

1.2.1. Phng php quang ph hp th nguyn t (AAS) ............................................... 6

1.2.2. Phng php quang ph pht x nguyn t (AES) ................................................ 7

1.2.3. Phng php quang ph hp th phn t UV-VIS ................................................ 7

1.3. Phng php quang ph hp th phn t UV-VIS .................................................... 8

1.3.1. Gii thiu phng php quang ph hp th phn t UV-VIS ................................ 8

1.3.1.1. S hp th nh sng ca dung dch mu .............................................................. 9

1.3.1.2. Cc nh lut c bn v s hp th nh sng ..................................................... 10

1.3.1.3. Cc i lng hay s dng ................................................................................ 10

1.3.1.4. Tnh cht ca mt quang v ng dng trong ha phn tch ........................... 11

1.3.2. Cc iu kin ti u ca php o quang .............................................................. 12



1.3.3. Cc phng php phn tch nh lng s dng phn tch: .............................. 12

1.3.3.1. Phng php ng tiu chun ......................................................................... 12

1.3.3.2. Phng php thm chun .................................................................................. 13

1.3.3.3. u im ca phng php UV VIS ............................................................... 13

1.4. Cc phng php ly v x l mu .......................................................................... 14

1.4.1. Phng php ly mu .......................................................................................... 14

1.4.2. Cc phng php x l mu v bo qun mu ...................................................... 14

1.5. S lc vi nt v ni ly mu ................................................................................ 14

1.5.1. H Thc Gin Vnh Trung ................................................................................. 14

1.5.2. Sng Ph Lc ...................................................................................................... 18

1.5.3. Nh my thp ...................................................................................................... 18

1.6. Chun b mu phn tch ......................................................................................... 18

CHNG 2: THC NGHIM V PHNG PHP NGHIN CU ......................... 19

2.1. Dng c, thit b, ha cht ...................................................................................... 19

2.1.1. Dng c ............................................................................................................... 19

2.1.2. Thit b ................................................................................................................ 19

2.1.3. Ha cht .............................................................................................................. 21

2.2. Pha cc loi dung dch ............................................................................................ 21

2.3. Nhng vn cn nghin cu ................................................................................. 22

2.4. Thc hin nghin cu iu kin ti u phn tch hm lng st trong nc bng

phng php quang ph hp th phn t UV-VIS. ........................................................ 22

2.4.1. Chn thuc th thch hp ..................................................................................... 22

2.4.2. Kho st bn mu ca phc Fe2+ v thuc th theo thi gian........................... 22



2.4.3. Kho st nh hng ca pH ................................................................................. 23

2.4.4. Kho st gii hn pht hin ca Fe2+ .................................................................... 23

2.4.5. Kho st gii hn nng tuyn tnh ................................................................... 23

2.4.6. Lp ng chun xc nh st .............................................................................. 24

2.4.7. Kho st cc yu t nh hng............................................................................. 24

2.4.7.1. Kho st nh hng ca Cu2+ i vi xc nh Fe2+ .......................................... 24

2.4.7.2. Kho st nh hng ca Co2+ i vi xc nh Fe2+ .......................................... 25

2.4.7.3. Kho st nh hng ca Ni2+ i vi xc nh Fe2+ ........................................... 25

2.4.7.4. Kho st nh hng ca Zn2+ i vi xc nh Fe2+ .......................................... 25

2.4.7.5. Kho st nh hng ca Cr3+ i vi xc nh Fe2+ ........................................... 25

2.4.8. Phng php loi tr cc yu t nh hng ......................................................... 25

2.5. Chun b mu gi .................................................................................................... 26

2.6. nh gi hiu sut thu hi ...................................................................................... 26

2.7. nh gi sai s thng k ca phng php ............................................................. 26

2.8. Quy trnh phn tch ................................................................................................. 26

2.9. Phn tch mu thc t.............................................................................................. 26

2.9.1. Ly v chun b mu ............................................................................................ 26

2.9.2. Phn tch mu ..................................................................................................... 27

CHNG 3: KT QU V BN LUN .................................................................... 28

3.1. Kt qu kho st xc nh st .................................................................................. 28

3.1.1. Kt qu kho st bn mu ca phc Fe2+ v thuc th theo thi gian .............. 28

3.1.2. Kt qu kho st nh hng ca pH ..................................................................... 29

3.1.3. Kt qu kho st gii hn pht hin ca Fe2+ ........................................................ 29



3.1.4 Kt qu kho st khong nng tuyn tnh ......................................................... 30

3.2. Kt qu xy dng ng chun............................................................................... 31

3.3. Kt qu kho st cc yu t nh hng ................................................................... 31

3.3.1.Kt qu kho st nh hng ca Cu2+ i vi xc nh Fe2+ ................................. 31

3.3.2. Kt qu kho st nh hng ca Co2+ i vi xc nh Fe2+................................. 32

3.3.3. Kt qu kho st nh hng ca Ni2+ i vi xc nh Fe2+ ................................. 33

3.3.4. Kt qu kho st nh hng ca Zn2+ i vi xc nh Fe2+ ................................. 34

3.3.5. Kt qu kho st nh hng ca Cr3+ i vi xc nh Fe2+ ................................. 35

3.4. Quy trnh phn tch xc nh hm lng st trong mu nc .................................. 37

3.5. Kt qu kho st hiu sut thu hi ca phng php ............................................... 37

3.6. Kt qu nh gi sai s thng k ca phng php ................................................. 38

3.7. Kt qu phn tch thc t ........................................................................................ 39

3.7.1. Kt qu phn tch mu thc t h Thc Gin Vnh Trung ............................... 39

3.7.2. Kt qu phn tch mu thc t sng Ph Lc .................................................... 42

3.7.3. Kt qu phn tch mu thc t nh my thp ..................................................... 42

CHNG 4: KT LUN V KIN NGH .................................................................. 43

4.1. Kt lun .................................................................................................................. 43

4.2. Kin ngh ................................................................................................................ 43

TI LIU THAM KHO ............................................................................................. 44



DANH MC CC BNG TRONG KHA LUN

STT NI DUNG Trang

1.1 S hp th mu ca dung dch mu 8

3.1 S ph thuc ca mt quang D theo thi gian.(nng st

0,001mg/ml, pH=4) 27

3.2 Bng kt qu kho st nh hng ca pH.(nng st

0,001mg/ml,o sau khi to phc 10 pht) 28

3.3 Bng kt qu kho st khong nng tuyn tnh Fe2+ 29

3.4 Bng kt qu lp ng chun ca Fe2+(pH=4,o quang sau 10

pht) 30

3.5 Bng kt qu kho st nh hng ca Cu2+ i vi xc nh Fe2+ 30

3.6 Bng kt qu kho st nh hng ca Co2+ i vi xc nh Fe2+ 31

3.7 Bng kt qu kho st nh hng ca Ni2+ i vi xc nh Fe2+ 32

3.8 Bng kt qu kho st nh hng ca Zn2+ i vi xc nh Fe2+ 33

3.9 Bng kt qu kho st nh hng ca Cr3+ i vi xc nh Fe2+ 34

3.10 Hiu sut thu hi ca phng php i vi php xc nh st 37

3.11 Bng kt qu D nh gi sai s thng k ca phng php 37

3.12 Bng kt qu nh gi sai s thng k ca phng php 38

3.13 Kt qu phn tch mu thc t thng 3 h Thc Gin-Vnh Trung. 39

3.14 Kt qu phn tch mu thc t thng 4 h Thc Gin - Vnh Trung 40

3.15 Kt qu phn tch mu thc t sng Ph Lc 41

3.16 Kt qu phn tch mu thc t nh my thp 41



DANH MC CC HNH V, TH

STT NI DUNG Trang

1.1 Dy mu ca nh sng trng 8

1.2 th tuyn tnh gia D v C 11

1.3 Quang cnh h Thc Gin-Vnh Trung 14

1.4 Bn h Thc Gin Vnh trung 16

1.5 Bn h Thc Gin Vnh trung 16

2.1 My phn tch UV-VIS 19

2.2 Cuvet 19

2.3 Lng knh hp th quang ph 19

3.1 S ph thuc ca mt quang D ca phc to bi st (II) v thuc

th o-phenantrolin theo thi gian. 27

3.2 th biu din s nh hng ca pH i vi vic xc nh st trong

nc. 28

3.3 th biu din nng tuyn tnh i vi xc nh Fe2+ 29

3.4 ng chun ca php xc nh st bng thuc th o-phenantrolin 30

3.5 th biu din s nh hng ca Cu2+ i vi xc nh Fe2+. 31

3.6 th biu din s nh hng ca Co2+ i vi xc nh Fe2+ 32

3.7 th biu din s nh hng ca Ni2+ i vi xc nh Fe2+ 33

3.8 th biu din s nh hng ca Zn2+ i vi xc nh Fe2+ 34

3.9 th biu din s nh hng ca Cr3+ i vi xc nh Fe2+ 35

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