Nghiên cứu phương pháp tách, xác định lượng nhỏ Molypden trong lượng lớn Vonfram và ngược lại : Luận án TS. Hoá học: 62 44 29 01

DAI HOC QUOC GIA HA NOI
TRl/dNG DAI HOG KHOA HOG T l / NHIEN
Sfi 5)C ijC

Dong Kim

Loan

NGHIEN Ctru PHl/ONG PHAP
TACH, XAC DINH Ll/ONG NHO MOLYPDEN
TRONG LirONG L<3N V O N F R A M VA N G U O C LAI
Chuyen nganh: Hoa Phan tich
Ma so : 62-44-29-01

LUAN AN TIEN SI HOA HOC

NGUOl HUONG DAN KHOA HOC

GS. TSKH. Lam Nsoc Thu

HA NOI - 2006


MUG LUG

Tranj

Danh muc cac ky hieu va chu vi^t t4t
Danh muc cac bang
Danh muc cac hinh ve, 66 thj

MODAU
Chirorng 1. TONG QUAN
1.1. Su- ton tai va irng dung cua molypden va vonfram
L1.1. Sir ton tai va phan bo tir nhien cua molypden va vonfram

A

L 1.2. Dae diem nguyen to, tinh chat vat ly va nhCrng ijng dung

5

CO ban ciia molypden va vonfram
1.1.3. Vai tro sinh hoc ciia molypden va vonfram
1.2. Hoa hoc ve molypden va vonfram

7
9

1.2.1. Ion molypdat va vonframat trong dung dich

10

1.2.2. Phuc chelat cua Mo va W

15

1.2.3. Phirc lien hop ion cija Mo va W

19

1.3. Cac phuong phap tach va lam giau molypden va vonfram

21

1.3.1. Phuong phap ket tiia

21

1.3.2. Cac phuong phap chiet

23

1.3.3. Cac phuong phap sac ky

28

1.3.4. Tach bang chung cat

32

1.4. Cac phuong phap phan tich molypden ben canh vonfram va

33

nguo'c lai
1.4.1. Xac djnh bang cac phuong phap hoa hoc

33

1.4.2. Cac phuong phap pho phan tu

36

1.4.3. Cac phuong phap khac

40

Chuong 2. THIJC NGHIEM

42

2.1. Phuong phap luan va no! dung nghien ciru

42

2.2. Hoa chat, thiet bj va phu-ong phap nghien ciru

45


2.2.1. Hoa chat
2.2.2. Thiet bi nghien ciru
2.3. Phu-orng phap thyc nghiem
2.3.1. P h u o n g phap do pho hSp thu phan ttj

4:
4'
45
4{

2.3.1.1. Xac djnh buoc song h§p thu cue dai

4J

2.3.1.2. Nghien curu anh huong cija nong do axit

4c

2.3.1.3. Khao sat anh huong ciia moi truang nuoc - dung

4S

moi hijii CO

2.3.2. Phuong phap chiet - trSc quang
2.3.2.1. Phuong phap chiet - trSc quang nghien ciju phuc

5(;
5C

Mo(VI) va W(VI) voi T O A B trong moi truong nuac axeton
2.3.2.2. Phuong phap chi^t-tr5c quang nghien cuu lien

51

hop ion giua Mo(VI) va W(VI) voi CV va BG trong moi
truong nuoc - axeton
2.3.2.3. Phuong phap danh gia va xay dung duong

53

chuan xac djnh M o 0 2 ' ^ b^ng T O A B va H^W^O:,'" bang
b a z o mau hChi c o
2.3.3. Chuan bj mau phan tich ICP-MS

54

2.3.4. He thong trao doi ion kin hoi dung moi

54

2.3.4.1 .Thiet ke, lap dat thiet bi trao doi ion on dinh

54

nong do axeton
2.3,4.2. Xay dung dirang chuan xac dinh nong do axeton

2.3.5. Ky thuat trao doi ion trirc tiep trong moi tnrong nuoc -

56

57

dung moi hiru ca
Chirong 3. KET QUA VA THAO LUAN

59

3.1. Nghien ciru kha nang tao noi phuc (chelat) cua Mo va \\

59

trong moi tru*6ng nu-oc va niroc - dung moi hiru cc


3.1.1. Phuc chelat cua Mo(VI) va W(VI) trong moi truang

5-

3.1.2. Phuc chelat ciia Mo(VI) va W(VI) trong moi truong

6:

nuac

nuac-dung moi hiru ca
3.1.3. Nghien curu kha nang tao noi phuc cua Mo(VI) va W(VI)

6;

vai TOAB trong moi truang nuac - axeton
3.1.4. Quy trinh chiet-tr^c quang xac djnh Mo(VI) ben canh

6i

W(VI) bang thuoc thu TOAB trong moi truong nuac - axeton
3.2. Nghien ciru kha nang tao lien ho-p ion cua Mo(VI) va W(VI)

7]

voi bazo- mau hiru co- trong moi tru-crng nxr&c - axeton
3.2.1. Nghien cuu kha nang tao lien hop ion cua Mo( VI) va

71

W(V1) voi brilian xanh (BG) trong moi truong nuoc - axeton
3.2.2. Nghien cuu kha nang tao lien hap ion ctta Mo( VI) va

7"/

W(V1) voi tim tinh the (CV) trong moi truang nuoc - axeton
3.3. Nghien cuu tach true tiep Mo(VI) va \V(V1) b^ng ky thuat

85

trao doi ion trong moi truong nu-oc - axeton
3.3.1. Khao sat kha nang \uu giu va ma giai cua Mo( VI) va

85

W(VI) tren nhya cationit
3.3.1.1. Nghien cim anh huong cua pH moi truong

88

3.3.1.2. Nghien cuu anh huong cua cac axit hCru co co

90

kha nang tao dem
3.3.1.3. Nghien ci'm anh hirong cua toe do pha dong

91

3.3.1.4. Nghien ciru anh hirong cua tac nhan rira giai

93

3.3.1.5. Nghien ciai anh hirong cua nong do \'a the tich

94

chat rura giai
3.3.2. Khao sat kha nang luu giCr va rira giai cua Mo( VI) va

96

W(VI) tren nhira anionit
3.3.2.1. Nghien curu anh hirong ciia pH moi trircrng

99


3.3.2.2. Nghien curu anh huong cua cac axit hiru co co
kha nang tao dem

10(

3.3.2.3. Nghien curu anh huong cua toe do pha dong

10:

3.3.2.4. Nghien curu anh huong ciia tac nhan rtia giai

1 o:

3.3.2.5. Nghien curu anh huong ciia n6ng do chit rua giai

1 Of

3.4. Nghien ciru anh hu-o-ng cua nong do Mo(VI) den kha nang

10'

tach W(VI) va ngu-o-c lai
3.4.1. Chuan bi thi nghiem

lO";

3.4.2. Khao sat kha nang tach hon hop Mo(VI) va W(VI) tren

10^

cot cationit va anionit
3.4.3. Nghien cuu anh huong ciia lugng ion Mo den kha nang

109

tach lugng nho W tren cationit

3.4.4. Nghien cuu anh huong ciia lugng Ian W den kha nang

1]1

tach lugng nho Mo tren anionit
3.5. Nghien ciiu thir nghiem tach Mo va W tren mau gia

113

3.5.1. Nghien cuu tach Mo khoi W tren cot cationit

1 13

3.5.2. Nghien ciju tach W khoi Mo tren cot anionit

114

3.6. Thu- nghiem tach va xac djnh Mo, VV trong mau thuc te

116

KET LUAN

119

CAC CONG TRJNH D A CONG BO LIEN QUAN DEN LUAN AN

121

TAI LIEU THAM KHAO

122

PIIULUC

139


DANH MUC CAC KY HIEU VA CHlT VIET TAT
Tieng Viet

Tieng Anh

Nhiet do nong chay

Smelling Temperature

Viet tat
nc

Nhiet do sol

Boiling Temperature

Nang lirgng ion hoa

Ionizing Energy

Etylendiamintetraaxetic axit

Etylenediaminetetracetic acid

EDTA

Metylisobutylxeton

Metylisobutylcetone

MIBK

Methotrimeprazin

Methotrimeprazine

MTM

Cetyltrimetylamoni

Cetyltrimetylamonium

CTMA

Phan tich kich hoat natron

Neutron Activated Analysis

NAA

Quang pho hap thu nguyen tur

Atomic Absorption

AAS

T.

Spectrometry
Khoi pho plasma cam irng

Inductively Coupled Plasma

ICP-MS

Mass Spectrometry
Quang pho hap thu nguyen tir

Flame Atomic Absorption

ngon Ilia

Spectrometr\'

Quang pho hap thu nguyen tur

Graphite Funace Atomic

16 graphit

Absorption Spectrometry

Quang pho phat xa plasma

Inductively Coupled Plasma

cam urng

Optic Emision Spectrometry

Lumogallion

Lumogallione

LG

Brilian xanh

Brilliant Green

BG

Tim tinh the

Crystal Violet

CV

Trioxiazobenzen

Trioxvazobenzene

TOAB

Dimetylfoocmamit

Dimetvltbrmamide

DMF

F-AAS

GF-AAS
ICP-OES

Khong phat hien

KPH

Nong do kim loai (Mo AV)

C KI


DANH MUG GAG BANG
Ten bang

Trane

Bang 1.1. Ham lugng Mo trong cdc dSi tuang tu nhien
Bang 1.2. Cdc khodng chuyeu cua W
Bang 1.3. Mot so dgc diem cua molypden vd vonfram

Bdng 1.4. Cdc dang cua ion molypdat a 2(fC
Bdng 1.5. Cdc cdch phoi tri cua cdc nguyen tu vai Mo vd W khi tgo
chelat

16

Bdng 2.1. Danh muc cdc thuoc thu sir dung trong nghien ciru

46

Bdng 2.2. Cdch chudn bi dung dich phdn tich

50

Bang 2 J. Nong do thuoc thu du trong dung dich nghien cuu

53

Bdng 2,4. Anh hirang cua nong do kim loai den do hap thu quang

54

Bdng 2,5. Sir bien dong cua nong do axeton trong qua trinh khao sat

57

Bdng 3.1. Suphu thuoc cua do hap thu quang vdo pH dung dich

62

Bdng 3.2. Sir phu thuoc cua do hdp thu quang vdo hdm luang dung

63

moi
Bang 3.3. Bien thien do hdp thu quang theo nong do axeton

73

Bdng 3.4. Anh hirong cua pH den do hdp thu quang cua lien hap

75

Bang 3.5. Khoi lirgng Mo(VI)

86

thu dirge Id' cdc phdn

Bang 3.6. Khoi lirgng IV(Vl) thu dirge tgi cdc phdn
'.

'

'.

~

'

dogn
dogn
'

87
—

Bdng 3. 7. Anh huang cua pH pha dong den hieu sudt trao doi

89

(HSTD) ion tren nhua cationit
Bdng 3.8. Anh huang cua cdc axit HC den HSTD ion cua Mo vd \V

90

Bang 3.9. Anh huang cua toe do pha dong den hieu sudt trao doi ion

92

Bdng 3.10. Hieu sudt rua giai Mo cua cdc lac nhan khac nhan

94

Bdng 3.11. Anh huang cua nong do HCI den kha nang rua giai Mo

95

11

Bdng 3.12. Khoi luomg Mo trong cdc phdn dogn rua giai
Bdng 3.13. Khoi luomg W trong cdc phdn dogn rua gidi
Bang 3.14. Anh huang cuapHpha
tren nhua anionit

\

97
99

dong din hieu sudt trao ddi ion \ loo

Bdng 3.15. Anh huang cua axit HC den hieu sudt trao ddi ion tren
anionit

101

Bdng 3.16. Anh huang ciia toe do pha dong den hieu sudt liru

102

gilt vd rira gidi W tren eot anionit
Bdng 3.17. Hieu sudt rira gidi W tren anionit

104

Bdng 3.18. Anh huang ciia nong do NaOH den kha nang rua

105

gidi W
Bdng 3.19. Hieu qud tach Mo vd W tren ionit

108

Bdng 3.20. Ket qud tdch lugng nho IV khoi lugng Ian Mo tren

110

cot cationit
Bang 3.21. Ket qua tdch lugng nho Mo khoi lugng Ian /L tren

112

cot anionit
Bang 3.22. Ket qua phdn tich Mo vd W trong dung dich rua giai

114

tren cationit
Bang 3.23. Ket qua phdn tich IV vd Mo trong dung dich rua giai

115

tren anionit
Bang 3.24. Khoi lugng kitn logi trong dung dich rua giai
Bang 3.25. Khoi luang kitn logi trong dung dich doi qua cot

111

117
17


DANH MUG GAG HINH VE VA DO THI
TEN HINH VE, DO THI

Trang

Hinh 1.1. Su chuyen dich cdn bdng giita cdc dang tSn tgi ciia W(VI)
theo pH

12

Hinh 2.1. Sa do he thong trao doi ion on dinh ndng do axeton

55

Hinh 2.2. Duong chudn xdc dinh ndng do axeton thong qua chiit

57

sudt cua dung dich
Hinh 3.1. Pho hdp thu quang ciiaphitc Mo(VI) vd W(V1) vai TOAB

60

trong moi truang nuac
Hinh 3.2. Phdn irng ciia Mo vd Wvdi TOAB

Hinh 3.3. Anh huang ciia pH den do hdp thu quang cua phirc

62

Hinh 3.4. Anh huang ciia nong do dung moi him ca den do hdp phu

63

quang ciia phirc Mo(VI)-TOAB vd W(Vl)-TOAB
Hinh 3.5. Pho hdp thu quang cua phirc Mo(Vl)-TOAB vd IV(Vl)
TOAB trong nudc-axeton

64

30% (V/V) vd pH 3

Hinh 3.6. Anh huang ciia ndng do axeton den do hdp thu quang cua

64

phirc Mo(Vl)-TOAB vd W(VI)-TOAB
Hinh 3.7. Pho hdp thu quang ciia phirc MoOj - TOAB. thuoc thu
TOAB vd dung dich W(VI) vai TOAB trong nudc-axeton 30% pH 3
sau khi duac chiet vdo toluen
Hinh 3.8. Anh huang cua ndng do axeton den do hdp thu quang cua
phirc M0O2 - TOAB vd WjVl) - TOAB sau khi chief toluen
Hinh 3.9. Duang chudn xdc dinh Mo ben cgnh \V bdng chiet trdc

66

67
69

quang vai TOAB trong moi truang nuac - axeton 30%
r

71

Hinh 3.10. Cong thuc cdu tgo cua BG
Hinh 3.11. Pho hdp thu quang cua lien hap> ion giCra \k)( 11) vd

72

W(VI)vaiBG
H]nh 3.12. Anh hirang cua ndng do axeton den do hdp phu quang
cua lien hap ion

IV

1


Hinh 3.13. Bien thien cua do hdp thu quang theo pH dung dich

\

7?

Hinh 3.14. Dudmg chudn xdc dinh W bdng chiit trdc quang vai BG
trong moi truang nudc-axeton

11

Hinh 3.15. Cong thicc cdu tgo ciia CV

78

•7

^

- ^ ^ ^ ^ ^ ^ ^

- ^ ^ ^ ^ _ _ ^ ^ _

Hinh 3.16. Pho hdp thu quang cua Mo(VI) vd W(VI) vai CV

78

Hinh 3.17. Anh huang cua nong do axeton din do hdp thu quang cua

79

lien hap ion giita Mo(VI) vd W(VI) vai CV,
Hinh 3.18. Anh huang cua pH dung dich den do hdp thu quang cua

80

lien hap ion giua Mo(VI) vd W(VI) vai CV
Hinh 3.19. Duang chudn xdc dinh W bdng chiit trdc quang vai CV

82

trong moi truang nude - axeton
Hinh 3.20. Khoi luang Mo trong cdc phdn dogn

86

Hinh 3.21. Ket qud rua giai W

87

Hinh 3,22. Anh huang cua toe do pha dong den hieu sudt liru giu vd

92

rua gidi Mo
Hinh 3.23. Anh hirang cua ndng do HCI den kha ndng rua giai Mo

96

Hinh 3.24. Ket qud rira gidi Mo

97

Hinh 3.25. Khoi luang W trong cdc phdn dogn

99

r

r

I

Hinh 3.26. Anh huang cua toe do pha dong den hieu sudt lim giu vd
rua gidi W

103

Hinh 3.27. Khoi luang W trong cdc phdn dogn rua giai bdng NaOH

106

a cdc ndng do khdc nhau
Hinh 3.28. Mo phdng duang cong rua giai \V bdng XaOH tren
anionit vai cdc ndng do khdc nhau

106


MdDAU
Molypden va vonfram la mot cap kim loai hi^m co nhung tinh chit vat
ly rat quy gia nhu dan dien va nhiet t6t, co nhiet do nong ch4y rk cao, kho soi
va dac biet la rk cumg. Nha vay ma chiing co vai tro quan trong trong nhi^u
nganh cong nghiep, tieu bi^u la cong nghiep luyen kim (thep chiu nhiet, chiu
mai mon, chiu axit...), cong nghiep dien, dien tu (day toe bong den. cuon day
16 dien, 6ng Ronghen, dien cue) va mot s6 nganh cong nghiep vat lieu mai
tien tien khac.
Ve mat hoa hoc, molypden va vonfram la hai kim loai nang nam trong

nhom cac kim loai chuyen tiep d nen kha b6n virng trong moi truang va co
nhung tinh chat hoa hoc rat phuc tap va phong phu. Trong cong nghiep hoa
hoc, chiing thuang dugc sir dung lam cac xuc tac cho cac qua trinh hoa dau,
xir ly moi truang; sir dung lam men mau, hoa chdt co ban. phu gia dac biet
chiu an mon a nhiet do cao va nhieu muc dich khac. Ngoai ra mol\pden con
la mot nguyen to vi lugng thiet yeu doi voi mot so enzym quan trong cho
chuyen hoa trong co the dong, thuc vat va la mot ngu\ en to c6 dinh dam cho
cay trong.
Chi chiem khoang K5.10" ^o khoi lugng vo trai dat va lai phan bo rdt
tan man trong moi truong, nen ben canh vice can thiet phai co cac phuong
phap phan tich nhay, chgn Ipc phuc vii cho \ iec dieu tra. tham do tai ngu\ en
va luyen kim; thi de co dugc molypden va vonfram tinh khiet cao can phai co
phuong phap tach uu viet. Song do tinh chat hoa hoc cua chung rat giong
nhau, nen vice tach va xac dinh mot trong hai ngu\en to luon luon bi ngu\en
to kia can tro. Vi vay, trong qua trinh tim kicm cac ky thuat dc tach mol\ pden
va vonfram, nmroi ta thironu co uaniz tao ra su khac biet dii Ion ha\ nho ^iua
chung nham tao dieu kien thuan Igi cho qua trinh tach nlur dua \ao trang thai
oxi hoa-khu, dieu kien ket tua, kha nang tao phuc. tach sac ky \a chiet...


Mot van de h6c bua nhung cung rat thu vi khi xem xet trang thai hoa tri
+6 ciia molypden va vonfram la kha nang tdn tai ddng thai a ca dang cation
va anion ciia chung. Ty le a cac dang ion trai d4u nay phu thuoc rk chat che
vao dieu kien moi truong nhu pH, ban chit cua dung moi, n6ng do ciu tu ...
Can cu vao dj thuong nay va dac biet la mong mu6n tim dugc cong nghe tach
hieu qua lam sach W ra khoi Mo va ngugc lai. chiing toi da ti^n hanh nghien
cuu theo huong tim dieu kien d^ vonfram t6n tai a dang anion (H;Wft02r'") va
molypden o dang cation (MoGi'^). Sau do su dung phuong phap trao doi ion
dc tach true tiep chiing ra khoi nhau. Do vay. nhung nhiem vu chiing toi phai
giai quyet la:

- Tim moi truong hon hop nuoc

dung moi huu ca phu hgp va xac

dinh dieu kien de hai kim loai nay mot ton tai a dang cation va mot tdn tai a
dang anion. Nho do co the tach chiing bang phuong phap trao doi ion hay xac
dinh chiing bang cac phuong phap trac quang chiet-trac quang.
- Lap dat he thons tach trao doi ion co kha nanu uiu on dinh ham iuans
dung moi huu co trong suot qua trinh tach.
- Khao sat dieu kien toi uu cho qua trinh tach Mo \a W tren hai loai
nhua cationit va anionit. Sau do nghien cuu kha nang tach lugng Ian ngu\en
to nay ben canh lugng nho nguyen to kia va ngugc lai.
- Xay dung quy trinh xac dinh lugng nho W ben canh lugng Ian Mo sir
dung ky thuat trao doi cation va quy trinh xac dinh lugng nho Mo ben canh
lugng kVn W sau khi trao doi tren nhua anionit.
- Tach va xac dinh Mo va W trong mau thuc te.
Nhung nghien cuu trong ban luan an na_\ dugc thirc hien tai:
-Bg mon Hoa phan tich, Khoa Hoa hoc. tnrang Dai hoc Khtxi hoc Tu
nhien, Dai hoc Quoc gia Ha ngi


-Phong thi nghiem Phan tich moi truong, Khoa Moi truang, truang Dai
hoc Khoa hoc Tu nhien, Dai hoc Qudc gia Ha ngi
-Trung tam Nghien cuu cong nghe moi truang va phat tri^n b^n vung,
truang Dai hgc Khoa hgc Tu nhien, Dai hgc Qu6c gia Ha ngi.


CHlTOfNG 1. TONG QUAN
1.1. S\/ TON TAI VA ITNG DUNG CUA MOLYPDEN VA VONFRAM
1.1.1. Su- ton tai va phan bo ty nhien cua molypden va vonfram

Molypden (Mo) va vonfram (W) la nhung nguyen t6 tuang d6i ph6
bian trong thien nhien (Mo chilm 3.10'" % va W chi^m 6.10""' % t6ng kh6i
lugng cac nguyen t6 tren v6 qua dk) [6]. Chiing khong co mat a dang nguyen
to tu do ma thuong a dang hgp chat trong cac khoang vat va trong cac d6i
tugng moi truang khac nhau nhud§t, nuoc, sinh vat... [6. 41. 42. 55, 56].
Bdng 1.1. Hdm luang Mo trong cdc doi tuang tu nhien
Ten

Cong thuc / Cac nguyen
dang

to di kem

Molypdenite M0S2

Cu, Re, Se

Wulfenite

PbMo04

Cu, Cr, W

Nuac tu

M0O4'"

Hau het

Ham lugng theo

Tai lieu tham

Mo

khao

0.01-0.25 °o

[55. 104]
[41. 134]

< 10)igl

nhien

[15.30. 71.
121. 134]

Sinh vat

M0O4'"

Nhieu

0.16-12 ma ks kho

[16.43.64.142]

Dk

Mo(VI)

Nhieu

0.02-24 ma ks dat

[61]

Molypden co mat it nhat trong 13 khoang. nhung chi co 2 khoang pho
bien la molybdenite va wulfenite. Nguon Mo chu \eu la trong quang sunfua
(molypdenite), voi ham lugng M0S2 trong khoang 0.3-0.6 *^o \a thuang cong
ket vai cac da ket tinh khac nhu granite, pegmatite, schiste cung nhu trong
mach quartz. Cac khoang it pho bien ho-n la ferrimol\bdate (Fe:0;.MoO;
.8H2O), powellite (CaMoOa) vaJordisite (Ca\\'(Mo)0,) [6. 28.41. 82iem thu dugc b4ng cac so dd gia dinh. Tuy nhien dav la vin dk rit
khd, vi Mo va dac biet W cd rit nhilu dang tdn tai trong mdi truong nuoc do cac
qua trinh ngung tu va nhilu tuong tac phuc lap khac. Vi vay khdng nen ddi hdi
nhieu d phan nay.
2-5/ Da nghien cuu cac dilu kien tach true tilp Mo-W bing trao ddi ion trong
he dung mdi hdn hgp HjO-Axeton. Day la mot ddng gdp mdi rit dang chu y
xuat phat tu ket qua nghien cuu cac dang tdn tai trong mdi trudng hon hgp H.OAxeton d cac pH khac nhau da thu dugc d cac phan tren. Dd thilt kl mot he ihi
nghiem don gian nhung dam bao dugc tdc do ddng dn dinh. Cac dilu kicn sau
day da dugc nghien ciiu:
2-5-1/ Vdi cationit axit manh Lewatit: trong khoang pH 2-3 cd the hap thu den
98,5 - 99% Mo vdi tdc do ddng 0,5-1 ml.cnr/phiit va cd the rua giai den 99%)
bing dung dich HCIO4 0,3 M.
2-5-2/ Vdi anionit bazo' manh Amberjet trong khoang pH 2,5 - 4,0 cd the hap
thu 98,5% W va cd thi rua giai din 99% bing dung dich NaOH 2.0M \ai tdc do
1,0 ml.cm'/phiit.
2-5-3/ Da ap dung nghien ciiu anh hudng ciia Mo den kha nang tach W \a

ngugc lai d cac ty le nong do khac nhau. Cac ket qua ihu dugc cho tha> khi
dirng cationit dl tach thi ngay ca khi ty le Mo:W 5000:1 sai sd cung chi khoang
6%.Cdn vdi anionit ngay ca khi ty le W; Mo 5000:1 sai sd cung chi khoang 5%.
2-5-4/ Da ap diino cac dilu kicn ircn cho mau gin \a mau hgp kim wonlVam cd
so sanh \oi phuong phap ICP-MS cac ket qua co the chap nhan dirge.
3- So sanh cac kc( gun ciia luan an > di c;ic cAntz trinh da co:
Luan an dua ra mot sd lugng Idn cac tai lieu tham khao (169), trong so do mot
sd khdng cd lien quan nhilu true tilp din ndi dung cua luan an. mdi sd luonu
sach (ircn 25 cudn) hoac co ndi dung khdng inrc tiep len quan hoac da
idn cac


cac tac gia trudc de giai quyet dugc muc tieu luan an da dat ra.Rieng phin sir
dung dung mdi hdn hgp nudc-axeton va phin su dung tach mot budc bane ionit
trong dung mdi hdn hgp la mot ddng gdp mdi. Mot phin kit qua ciia luan^an da
dugc cdng bd trong 2 cdng trinh cd dii do tin cay va cd thi ung dung v ao thuc tl.
4- Mot so thieu sot can chu y:
-Ve ndi dung: trong muc 2.3.2.1 va cac phin vl sau tuong ung, tai sao lai chon
ty le ndng do M : TOAB la 2:1 trong khi dd kit qua trong 3.1.4 ty le trong phiic
thi du Mo(VI): TOAB la 1:1.
- Ve hinh thuc: cac tai lieu tham khao tuy diy dii, nhung lan man, chua neu bat
dugc trgng tam da tham khao, di tu dd ngudi dgc de nhan thiy rd nhung net mdi
tiep tuc va sang tao cua luan an.
5- Ket luan:
Tuy cdn mot sd thieu sdt nhd nhu da neu, nhung ndi dung co ban cua luan an
da cd nhijng ddng gdp mdi vao viec tach va .xac dinh ddng thdi cap ddi
Molypden- Vonfram khi ciing cd mat vdi lugng Idn. Ndi dung ciia luan an dap
UTig day du yeu cau cua luan an cap tien sT hoa hoc phan tich, ten cua kian an
phu hgp vai noi dung va phu hgp vai chuyen nganh, torn tat luan an phan anh
trung thirc noi dung luan an. Tac gia luan an xirng dang dugc nhan hoc vi Tien sT

Hoa hoc, chuyen nganh Hoa hoc Phan tich.
Ha Noi, ngay 18 thang 1 nam 2007
Neuai nhan xet

PGS.TS. Tran Chuong Huyen
Bp mon HcSa hoc Phan tich
Dai hoc Khoa hoc Tu nhien Ha Noi


NGHlfiN Ctru PHirONG PHAP TACH, XAC DINH LUONG NHO MOLYPDEN
TRONG LUONG LON VONFRAM VA NGUOC LAI
CHUYEN NGANH : HOA PHAN TfCH
MA s o
62-44-29-01
NGHlfiN CtlU SINH DONG KIM LOAN.
PHAN BI£N 3
PGS.TS. NGUYEN THI PHUONG THAO
VlfiN KHOA HOC VA CONG NGH£ VI£T NAM
VI$N KHOA HOC VA CONG NGHfi MOI TRUONG
Sau khi dgc toan van ban luan an tren, tdi xin cd nhan xet sau:
I. Ve tinh cap thiet, thdi siJ, y nghia khoa hgc va thuc tiln cua dl tai.
De tai nghidn cuu phuong phap tach, xac dinh lugng nhd Molypden trong
lugng Idn Vonfram va ngugc lai la dl tai thudc hudng nghien cuu khoa hgc
CO ban trong linh vuc hoa phan tich. Day la dl tai cd y nghTa khoa hgc cao,
ra't cdn thiet va rat dang tran trgng vi d Viet Nam, nhOmg dl lai dang dl tai
nay ngay cang it dugc dau tu nghien cuu, it cd dugc nhuiig dl tai di sau vao
nghi6n curu khoa hgc co ban ma phan Idn la nghien cuu cdng nghe, trien khai,
V.V..

Va'n de dugc tac gia dat ra de giai quyet la ra't khd va thii vi bdi ly do:

+ Vonfram va Molypden cd nhilu dac diem gidng nhau nen ra't khd tach.
+ Xac dinh lugng nhd nguyen td nay ben canh lugng Idn nguyen id kia va
ngugc lai hoan toan khdng dl dang va ludn ludn gap phai trong khi .xay dung
phuong phap phan tich.
Chinh vi vay, dl tai nay cd y nghia thuc tiln rat Idn khi ap dung vao phan tich
mau thuc te.
II. Vdi 169 tai lieu tham khao, trong dd cd 156 tai lieu tieng .Anh va 13 tai lieu tieng
Viet, tac gia da tiep thu, ke thira mot each chgn lgc cac ket qua da dugc cdng
bd' dl ly giai nhirng gia thuyet va cd chl cac phan ung mot each trung thuc, rd
rang va d^y dii. Khong sao chcp. vi pham ban quyIn cung nhu khdng trung
lap cac ket qua da dugc cdng bd tren ihl g\ci\ cung nhu d Viet Nam
in. VI ndi dung: Phan anh dugc muc tieu dl ra, phu hctp ten luan an, ma so chuyen
nganh cua luan an: Nghien cuu ca ban trong ITnh vuc phan tich hoa hoc.
Trang 1 / 4


^ . 1 . l^huong phap luan: la logic, khoa hgc. Tac gia da lua chgn mot trong rat
It dac di^m khac nhau trong rat nhieu diem giong nhau ciia Molypden va
Vonfram de tach chung ra khdi nhau: dd la tim dilu kien tdi uu dl Mo (VI)
t6n tai chii ye'u dang Cation (MoG^^^) va W (VI) tdn tai chu yeu d dang
Anion (U-;Wf,02^^-), sau dd tach true tiep tren cot trao doi ion. Vdi phuong
phap luan chac chdn nhu vay da giiip tac gia thanh cdng va xac dinh dugc
lugng nho ben canh 1 lugng Idn cac nguyen td tren nhd phucmg phap tach sac
k^. Lua chon dugc dung mdi va ty le dung mdi thich hgp dl chiit thanh phan
ca'u tir nay (Mo) ra khdi ca'u tir khac (W).
4.2. Phuong phap va thiet bi sir dung:
Cac phuong phap dugc sir dung trong luan an la phuong phap phan tich
quang phd phan tir, ha'p thu nguyen tir, phuong phap khdi phd cam ung
Plasma cao tdn la cac phuong phap hien dai, dii do nhay, dd chgn lgc, dd
chinh xac dap ung hoan toan, day dii va thich hgp cho dl tai nghien cuu khoa

hgc CO ban chuyen sau.
Cac thiet bi sir dung dugc neu trong luan an la cac thiet bi hien dai nhai, the
he mdi nhat nen ke't qua tin cay va thuyet phuc.
V. Ket qua nghien cuu mdi ciia tac gia:
5.1. Ddng gdp mdi: Luan an da nghien curu thanh cdng cac muc tieu dat r?,
trong dd ddng gdp dugc 4 diem mdi ra't cd y nghTa:
-I- Da khang dinh dugc trong mdi trudng nude - aceton cd pH = 2,5 - 3,5; cd
ndng do aceton 30% thi Mo (VI) tdn tai dang Cation (M0O2'*) va W (VI) tdn
tai dang Anion (HjW^^Oj,^),
+ Tach dugc 2 ion tren bang phucmg phap sic ky ion
+ Tim dugc dilu kien tdi uu di tach duoc luong nhd Molypden canh luong
Idn Vonfram va ngugc lai dua tren ket qua chiet Mo va W (VI) vdi cac bazo
mau hiru ca khdng thdng qua trung gian.
+ Da lap dat dugc 1 he thdng edt sac ky cd kha nang giu dn dmh ndng dc
aceton trong sudt qua trinh tach.
Day la nhung ddng gop rat cd y nghTa trong nghien cuu khoa hoc co ban cu.
chuyen nganh hoa hgc phan tich, cd y nghTa cao trong ngh.en cuu khoa hoc
Trang 2 / 4


dirdi dang d6ng tac gia trong: Tap chf Hoi hoc (2); Tap chi phan tich Hoa Ly
"•* "'"* • * " ' • ' '*" ' "^^"^ " ° ^ » ' ™ Tap chi Khoa hoc
DHQG Ha Ndi (2).
HI'^U^M'^'

T^t ca cac cdng trinh cdng bd tren diu la ttag ph^n ke't qua cua tac gia da
dugc trinh bay trong luan an. Cac bai bao diu da duoc xet duyet, phan bien
trudc khi cdng bd vi vay hoan toan dam bao gia tri khoa hgc cua cdng trinh.
Ve ket caiu va hinh thurc cua luan an:
Ban luan an dai 138 trang, chia thanh 3 chuong: Ndi dung chinh: 115 trang;

Chuong I - Tdng quan: 38 trang; Chuong n - Thuc nghiem: 17 trang; Chuong II Kit qua va Thao luan: 60 trang. Cd 35 bang, 31 hinh ve va dd thi. Bd' cue, ke't cau
ciia luan an nhu tren la ra't hgp ly, logic.
Hinh thurc ciia luan an: dep, rd rang, sang siia, it Idi chinh ta.
Tuy nhien, xin cd 1 sd gdp y sau:
1. Tdng the each hanh van: Tac gia cdn sir dung dang van ndi (Chiing tdi
lam the nay, chiing tdi lam the kia,...) vao van viet khoa hgc nen ngudi dgc cam
giac tac gia md ta trinh tu. Vi du: trang 81: "chiing tdi da", "chiing tdi chuAn bi",...;
trang 68, 70, 72, 73, 74 tuong tu. Viet hoi dai, ddi chd rudm ra (trang 1)
2. Mijc liic: Nen thdng nhat cac tieu dl: viet ten chir hay ky hieu cua
Molypden va Vonfram ?
3. Ngi dung:
+ Chuong I: trang 33: Phuong phap trgng lugng khdng phai la phucmg phap
thudng diing de kiem tra lai nong do dung dich chuan (khdng rd nghTa)
+ Chuomg II: Phuong phap luan va ndi dung nghien cuu: trang 42: Viet hoi
dai, chua neu bat dugc can cu cua phuong phap luan cua luan an dugc dan dat tu
tdng quan (trang 42 mot sd chd nen chuyen sang tdng quan)
+ Chuong n i :
- Muc 3.1.1, trang 59 hoi dai, lap lai, phan TOAB (trang 60) nen dua sang
tdng quan.
- Trang 61: anh hucVng pH manh, cdn xem lai. Theo ngudi dgc thi pH tir 1 - 4
: khdng anh huong. Khdng nen viet "pH xung quanh ba" ma nen vict "pH khoing
3"
Trang 3 / 4


- Cdng thurc cau tao va tinh chat ciia TOAB, GB va CV nen cho vao tdng
quan
- Trong cac bi^u d6, d6 thi khdng c^n thiet noi qua chfnh xac tu diem nay
din dilm khac ma nen ve theo kha nang dd lech tan man. Vi du hinh 3.4, cue dai d
30% aceton chua dugc hop l^ lam. D6 thi cho d die'm nay hoi nhgn qua. Tai sao

khdng la'y phd ghi dugc tren thiet bi ma ve lai?
Tren day la mot sd gdp y nhd cho ban luan an tien sy cua nghien cuu sinh
Ddng Kim Loan. Nhin chung, ngudi dgc danh gia cao cdng trinh nghien cuu nay.
Tac gia nam kha virng vl ly thuyet co ban ciia hoa hgc phan tich, giai thich chat che
mgi hien tugng va co che' phan ung tach chiet. Xay dung dugc md hinh thuc nghiem
logic, khoa hgc va thirc su cd tu duy thuc hanh tdt khi thiet ke he chiet kin giu ndng
do aceton d 30%.
Khdi lugng thi nghiem nhilu, sd lieu khdng Id, logic va tin cay. Tac gia cd
kha nang tu duy nghidn cuu dgc lap mot va'n dl thudc nghien cuu co ban.
K ] £ T LUAN CHUNG:
1. Ban luan an dap ung dii yeu cau cua 1 luan an tien sy theo quy dinh tai
dilu 20 ciia quy che'
2. Ban tdm tat luan an la phan thu ggn ciia toan van luan an nen phan anh
trung thanh ngi dung co ban cua luan an.
3. Dl nghi cho phep tac gia dugc dua luan an ra bao ve trudc hdi d6n~
cha'm luan an tien sy tai Hdi ddng Quoc gia cha'm luan an tien sy nganh Hoa hgc
phan tich. Tac gia sau khi bao ve thanh cdng trudc hdi dong xung dang nhan duoc
hgc vi Tien sy Hoa hgc.
vi$N

C 6 N G N G H $ M 6 I TRUCING

Hd Ndi, ngdy 18 thdng 01 nam 2007
Ngudi nhan xet

XAC NHAN C H i r K t
n Thi Phuimg Thao

mw

PGS.TS. Nguyin Thj Phmmg Thao

Trang 4 / 4


QUYET NGHj CUA HQI DONG
C H A M L U A N AN TIEN SY CAP NHA NUOC

Ve luan an ciia nghien cuu sinh: DONG KIM LOAN
De tai: "Nghien ciru phu'cmg phap lach, xac dinh linrng nho molxpclcn irong
lugng lan vonfram va ngirgc lai"
Chuyen nganh: Hoa Phan lich
Mas6:

62-44-29-01

Ngay 07 ihang 02 nam 2007 I lgi dong chain luan an cap nha niroc cht)
luan an ciia nghicMi cuu sinh Dong Kim Loan da hop lai I ruong Dai hoc Khtui
hgc Tu nhien de cham luan an noi iren. Sau phan khai mac. I loi dong da nyhc
nghien cuu sinh Irinh ha_\ lom lai ngi dung luan an. Sau khi nghe cac > kien
ciia nhan xet eua phan bien. ilgi dong da dai eau hoi \a nghien cuu smh ua
lai. Hoi d6ng da hgp d6 ra quxCl dinh danh gia luan an \ai nhung diem sau
day:
/. Y nghia khoa hoc va tinh thuc tien cua luan dn
Mol>pden \ a \onlram la hai kim loai ehu>en liep eo nhieu linh ehal
hoa hoc luanu lu nhau. lYonu dunu dieh eua chiing eae qua irinh hoa hgc \a\
ra nit phuc lap. NghiCMi ciiu phuong phap tach \ a xac dmh lirong nhc^ chai na\
khi cd mai lugng Idn chAl kia mgi cach don gian. hicu qua \a diinh xac luon
la mgi dl Uii cd y nghTa khoa hgc \ a ihuc lien cao. dap Ling nhu cau cua ph.in
tich thuc te.

2. Tinh h(/p ly, hien ihu yd do tin cciy cua phuong pimp ugliieu ciiu
Qua trinh llurc nghiem da dugc lac gia nen hanh moi cach hop K livn
CO sd xac dinh trang thai ion tai khac nhau cua cac ion Mo(Vl) ^^ \ \ ( \ 1 )


chiing bang phuong phap chiet va phuong phap sSc ky trao d6i ion la cac
phuong phap tach hieu qua lai don gian va kha thi. Ket hgp cac phuong phap
tach tren vdi viec xac dinh bang phuong phap quang ph6 hap thu phan tu la
hoan toan hgp ly. Cac sd lieu thu dugc rk phong phu \ a dang tin cav. Ket qua
phan tich mau thuc te da dugc thuc hien song song vdi phuong phap ICP-.VIS.
Do chenh lech nam trong gidi han cd thi chdp nhan dugc.
3. Cdc ket qud m&i ciia luan an vd gid tri cua chung
- Da xac dinh dugc dang ton lai khac nhau cua cac ion iMo(VI) va
W(VI) trong mdi trudng nude - axclon \di n(')ng do axeton chiem .^^f)'\, theo
the tich, trong khoang pll tu 2.5 den 3.5. Trong dicu kien nay Mo(VI) ton lai
chii yeu d dang cation (M0O2'') va W(VI) ton lai chu >eu o dang anion
(ll,W,02r'").
- Da nghien ciiu su tao phiic chelal cua cac ion iMo(\l) \a \ \ ( \ 1) \di
TOAB va sir tao lien hgp ion giua chiing \di eae ba/o JiOu eo nlur brilian
xanh hoac lim tinh the.

UXMI eo

so' dd ehiel Uieh ihanh e(msi hai ion tren

- Da su dung ky ihual Irao doi ion Uieh Iruc tiep hai nguven lo Mo \a
W ra khoi nhau ma khoniz can su dumi kie nhan lao phuc \r.\o iruoc ironu
hoac sau qua trinh Irao doi ion livn egl. Kel hop \ ice laeh irire liep eae iiguxen
td tren bang ky thuat Irao doi ion \ a xac dinh ehiing bang phirong phap trae
quang cho phep xac dinh lugng nho Mo trong lugng Ion W \ a ngugc lai mgi

each hicu qua va chinh xac.
4. Ve nhiKfc diem
Ban luan an cdn mgi so loi in an can ehinh sua iruoe klii nop.
5. Kc't luan

chung

1)1 Uii liKin an eo ngi Jung khoa hoe phu hop ma so ehii>en nganh 116a
Phiin lich 62. 44 26 01: khdng iriing lap \6i eae de tai da bao \e. C'ae kel qua
dat duoc cd do lin ca\ N a logic.


Kim Loan da dap ung day du mgi yeu cau cua luan an ti6n sy. Tac gia
cua
luan an xung dang dugc nhan hgc vi tiln sy hoa hgc.
Tat ca 7 thanh vien trong Hdi ddng deu nhat tri vdi qu\ It dinh na\.

;^/:-

Ha noi ngay 07 thang 02 nam 2007

^

Thu* ky Hoi dong

Chii tich Hoi dong

^

PGS. TS. Hoang Tho Tin

-•*•'

/ .

GS. TSKH. Irinli Xuan dian


Ho ten tac gia: Dong Kim Loan
Ten luan an: Nghien cuu phuang phap tach, xac djnh lugng nho mohpden irong
lugng Ion vonfram va ngugc lai
Nganh: Hoa hgc
Chuyen nganh: Hoa hgc Phan lich.

Ma so: 61-44-29-01

Don vj dao tao: Truang Dai hoc Khoa hoc Tu nhien, Dai hoc Quoc gia Ha noi
Trich yeu noi dung luan an
Muc dich vii doi twang nghien ciru:
Doi tugng nghien cuu cua luan an la phuong phap tach \a phan tich cap
nguycMi to hoa hoc molypden (Mo) \a vonfram (W) co linh chai \al ly \a hoa hoc
rat giong nhau.
Muc dich nghien cuu la: (1) Tim dieu kicMi trong moi irutrng nircVc

dung moi

huu CO de lao ra sir khac hiel ve dang Ion lai cua M(M\*ll \a \ \ ( \ h (2i Khao sal
kha nang lao ngi phiic \oi lrio\\a/ohcn/cn \a lao hen hop ion iruc iicp \a\ cac
baza mau huu co trong moi tnrong nuoc - dung moi huu c(V cua Mo \a \ \ : irng
dung vao phan lich Mo va W. (3) Nghien ciiu uieh iruc liep Mo|\ I) ra kht>i W (\ 11

va ngugc lai tren nhua trao doi ion. ma khong qua lao phiie irung gian irutre. irong
va sau qiui trinh trao doi '\on \ a nra giai.
Cdc phuong phap nghien ciru:
Phuo-nu phap chiet long - long dirge sir dung de nghien eiru kha nang lao
phiie va lien hop ion giua mol\pden \a \ontram \oi eae lae nhan tao noi phire \a
cac ba/o mau huu co trong moi irirong niroe \ a niroe - dung moi hCrii eo I ir Jo
khanu dinh dirov dieu kien de hai ngii> en l6 na> \dn lai o eae dang irai ngiroe nhau.
Phircrng phap trao doi ion iniv iiep nghien cuu kha nang taeh lircmg nho
ngmen to na\ trong luong Ion nguxcii to kia \a ngugc ku.
Cae phuong phap chiet trac quang. ph6 hap thu ngu>cn tu xa kh6i pho cam
img pUisnu. duoc su' dung de phan tich n6ng do kini loai trong dung dich.
Ciie ket qua eliinli cua luan an:
Da n-hien cuu tim ra anh huong cua niot s6 dung inoi hCru ccr tan den su
ehuvCn dieh^ean bang ^c dang .6n tai cua M o . \ h ^a U i M . . dac bie, la axclon ^a K


Nghien cuu xac djnh cac dieu kien toi uu de chill va xac dinh Mo \a W
irong moi truang nuac - axeton vai lac nhan tao noi phuc la trioxiazobenzen \ a tac
nhan tao lien hgp ion true tiep la tim tinh the va brilian xanh.
Nghien cuu lap dat thiet bj, xac lap cac thong so va dieu kien dh tach true
liep lugng nho Mo trong lugng lan W va ngugc lai tren nhua trao doi ion trong m6i
truang nuac - axeton.
Cac ket qua thu duge da dugc su dung de tach \a phan tich ihu nghiem mau
thuc te la kim loai vonfram thugng mai cho kel qua lot.
Kel qua nghien cuu eua luan an duge danh gia la nhung dong gop moi. quan
Irong trong hoa hgc va phan tich cap nguyen to quy hiem molypden \a \onfram.

Can bg hucVng dan

Nizhien cuu sinh

/V,^v_^

GS. TSKH. Lam Ngge Ihu

Done Kim I (vin


Author: Dong Kim Loan
Title of the thesis: Investigation of separation, determination of small amount of
molybdenum in tungsten and those on the contrary.
Branch: Chemistry
Speciality: Analytical Chemistry

Code: 61-44-29-01

Training Institution: Hanoi University of Science. Vietnam National University
Hanoi.
Summary of the Ph.D. Thesis content
Purpose and subject of the thesis:
The subject of the thesis was separation and determination method of couple
chemical elements - molybdenum and tungsten - having \er} sinular physical and
chemical properties.
The purpose of the thesis were: (I) Delerminalion (W ihe eondilions in water organic solvenls in order to create difference o\' Mo(\'l) and \ \ ( \ I) lormaliotTs. (2)
Investigation of chelate forming uilh liio.\ia/oben/ene anJ ion-pair uilh organic
bases of Mo and W in water - sol\enl media and appl\ in iheir anaixsis. (.>)
Investigation of direct separation of Mo(\'l) from \ \ ( \ ' l ) and those on the eoiiiraiy
on ion-exchange resin w ilhoiit using inlermediale complex fonmng helore ox during
exchange and elution.
The methods of investigation:

Liquid - liquid exlraclion was used for nnesligaliiMi of ehelale and ion-pair
forming ability between M o ( \ I ) and \ \ ( \ l ) unh respeeiixe agents in water solvent media. Then ihe eondilions were Jelermmed lor cxisienee of eonirar> forms
of moI> bdenum and lungsien.
Direct ion - exchange method was used for nn esligation of separation oi
small amount o\ Mo m W and those on the eontraiN.
IMraelion

speclropholometiN.

al
absorption

speelromelr>

and

inductnek couple plasma mass speetromelr> were used tor anaUs.s ofmetais
concentration in their.solutions.