Tuy nhien, nang lugng vimg cam ciia TiO; tinh kliiet klia ldn 3,25 eV ddi vdi anata va 3,05 eV ddi vdi rutin nen chi hoat dpng QXT trong viing tii ngoai gdn, va do dd chi cd the tan dung
Trang 1KHAO SAT KHA NANG PHAN HUY PARAQUAT TRONG T H U 6 C TRLf c6
DU'QI NGUdN ANH SANG NHJN THAY TREN BOT NANO Y-TiOj BUOC
OI^U CH^ BANG PHU'ONG PHAP THUY NHIET
Nguyen Van Hung'", Ngo Sy Luong^, Nguyen Hiru Hieu^
'Khoa Hda hgc, Tnrdng Dgi hgc Dong Thdp
^Khoa Hoa hgc Tnrdng Dgi hgc Khoa hgc Tu nhien Hd Ngi DHQG Hd NQi
Den Tda sogn 22-4-2012
Abstract
The effecl of experimental conditions on the degradation of paraquat in herbicide over Y-Ti02 powder prepared by hydrothermal method (particle size about 6-7 nm, specific surface area - 223.6 mVg) have been investigated Experimental results showed that suitable conditions arc' time for adsorption equilibrium about 60 minutes, amount of Y-TiOi per 200 ml herbicide solution with concentration of paraquat 19 mg/1 about 0.3g, the pH of solution about 7-8 and the degradation limes about 4 hours In the conditions, the concentrations of paraquat in herbicide after decomposing were lower than threshold (0.9 mg/1) It showed that ihe promise applications of Y-Ti02 powder in degradation of paraquat as well as other organic pollutants can obtain
Keywords: Titanium dioxide, Photocatalysl, paraquat, herbicide, Y-Ti02, doping, Y(III)
1 GIOI THIEU
Paraquat la mpt logi thudc diet cd khdng chpn
Ipc, thudng dugc sir dyng d cac nudc ndng nghiep
cho sy kiem soat cd dgi va cd la rdng tai khu vyc dat
trdng cay va cac khu vyc thiiy san Paraquat dugc
biet den nhu la chat gay d nhiem mdi trudng dat va
nudc mat, dpc hai ddi vdi con ngudi va dpng vat [I]
Lieu lugng gay hgi ciia nd tuang ddi thap Vi du,
lieu lugng gay hgi tuong lirng la 35 mg/kg doi vdi
ngudi va 36-54 mg/kg ddi vdi gia siic [1] C) Vipt
Nam, paraquat dugc sir dyng nhieu d cac tinh phia
Nam vdi ten thuong pham nhu Tungmaxone,
Nimajion 20SL nham dipt cd dgi d cac rupng liia va
hoa mau Gan day, d nudc ta sd ca ngp dpc paraquat
ngay cang tang va ngp dpc cap paraquat bat ke lieu
lugng nao deu cd the tu vong va hipn chua cd bipn
phap dieu trj hiru hipu nao Do paraquat cd dpc tinh
cao va ben vimg trong mdi trudng ddt va nude nen
viec nghien ciru tim ra phuang phap thich hgp d6
logi bd du lugng ciia chung la rat cdn thiet
Trong nhieu chat ban dan cd kha nang quang
xuc tac (QXT) nhu: TiOi, WO3, SrTiO,, FejOj,
ZnO, ZnS, CdS TiOj dugc chirng minh la phii hgp
nhat cho cac ung dyng rpng rai trong xir li mdi
trudng do Ti02 cd hogt tinh QXT cao nhdt, tro ve
hda hpc va sinh hgc, ben virng, khdng bj an mdn
thap [2] Tuy nhien, nang lugng vimg cam ciia TiO; tinh kliiet klia ldn (3,25 eV ddi vdi anata va 3,05 eV ddi vdi rutin) nen chi hoat dpng QXT trong viing tii ngoai gdn, va do dd chi cd the tan dung dugc mdt phan nhd (< 4%) ngudn nang lugng ddi dao tir mat trdi, lam gidi hgn kiia nang img dung thyc tien cua nd Do do, kl thuat bien tinh da dugc sir dung nham thay ddi cau tnic dipn tir va nang cao hoat tinh QXT ciia TiO: trang vimg anh sang nhin thay Cac ion ddt hiem dugc biet den vdi kha nang tgo phirc ciia chung vdi cac bazo Lewis (nhu amin, andehit, thiol, ) thdng qua tuong tac giira cac nhdm chirc ciia nhung baza vdi cac obitan f ciia ion dat hiem Do dd, ket hgp cac ion ddt hiem trong mgng ludi Ti02 cd the tgp trung cac chat 6 nhiem len be mgt chdt ban din, md rgng phan dng quang hoa den viing anh sang nhin thay va nang cao hipu qua tach giiJa cac c$p electron-Id trong cam quang ciia TiOi [3]
Da cd mpt so cdng trinh nghien ciru phan hiiy cac hpp chat huu ca (d dgng tinh khiet) h^n bpt TiOj bien tinh bdi ion Y^* va danh gia hogt tinh QXT cua chiing trong viing anh sang tu ngogi gdn [4, 5] Tuy nhien, den thdi diem hien tgi, chua cd cdng trinh nao cdng bo ve vi?c phan hiiy paraquat cd trong thudc trir cd (mau that) bdi bpt nano Y-Ti02 dudi sy chieu xg anh sang nhin thay Trong cdng trinh nay, chung tdi thdng bao mOt
sd ket qua khao sat kha nang ung dyng bpt Y-TiOj kich thudc nano dugc dieu che bdng phuang phip
Trang 2thiiy nhipt dung djch TiOS04 cd m^t ure thdng qua
kha nang phan huy hogt chdt paraquat cd trong thuoc
trir cd dudi buc xg cua dhn compact
2 PHUONG PHAP NGHIEN CUV
2.L Thyc nghifm
Cac hda chdt duprc su dung trong thyc nghipm
deu d dgng tinh khiet ma khdng can ch£ hda bo
sung
Chi t\k quy trinh dieu ch6 va cac y6u to anh
hudng da dugc cdng bo d cdng trinh [6] Ket qua
cho thdy, bpt Y-TiO; d ty Ip moi Y/TiO; 0,168% cd
hogt tinh quang xuc tac cao nhat nen mau nay va
mau Ti02 khdng bien tinh dugc tien hanh dieu che
theo nhCrng dieu kipn da dugc khao sat, cy the nhu
sau: Hda tan 4 gam TiOSOj vao 50 ml dung dich
H2SO4 0,18 M Cho tiep 10 gam ure va lugng muoi
Y(N03)3 xac djnh vao dung djch TiOSOj thu dugc
va khuay deu trong khoang 15 phiit, Ihu dugc dung
djch hon hgp Dung djch nay dugc cho vao
autoclave dung tich 100 ml va lien hanh thiiy nhipt
trong 18 gid d nhipt dp thich hgp Huyen phii thu
dugc sau khi thiiy nhipt dugc rua vai lan bdng nudc
cat va sau dd la etanol cho den khi khdng cdn phat
hien ion S04^" trong nudc riia (thir vdi dung djch
BaCb 0,2M) Bpt Y-TiO; thu dugc bdng each sdy
kho huyen phii sau khi rua d IIO^C trong 24 gid
Mau Ti02 khdng bien tinh dugc dieu che tuong ty
nhung khdng cd sy bd sung lugng mudi Y(N03)3
Hogt tinh QXT cua cac mau san pham dugc
danh gia bang each trpn lugng xac dinh bpt Y-Ti02
vao 200 ml dung dich thudc trir cd cd ndng dp
paraquat thich hgp, khuay deu hdn hgp trong bdng
toi den khi dat can bang hap phu-giai hap Sau do,
huyen phii dugc chieu xa trong khoang thdi gian
thich hgp bdi den compact Golstar 40 W vdi 3 vung
budc song dgc trung la 435 nm, 545 nm va 610 nm
Hieu suat phan irng QXT dugc xac djnh bang each
so sanh dp hap thy quang ciia dich trudc va sau phan
ung d eye dgi hdp thu X = 557 nm
2,2 Cac phu-Qng phap xac dinh
Gian dd XRD ciia bpt Ti02 dugc ghi tren nhi6u
xg ke tia X D8 Advance Brucker (Due) vdi tia CuK^
wX = 0,154056 nm, nhipt dg ghi 25°C, gdc 29: 10
^70°, toe dp quet 0,037s Kich thudc hgt trung binh
dupc xac djnh dya vao pic dac trimg tren gian dd
XRD theo cdng thuc Scherrer
Cac anh TEM cua san pham bpt TiO: dugc chyp
tren kinh hi^n vi dipn tir truyln qua JEMIOIO
(JEOL-Nhat Ban) cd hp sd phdng dgi M = x50 den
Nguyen Vdn Hung vd cgng su
40 den 100 kV Dipn tich be mat BET dugc xac dinh
til dudng ddng nhipt hdp phy-giai hdp nito tai 77 K
tren thiet bj Micromeritics (My)
cac gia trj dp hap thy quang cua dung djch paraquat dugc xac djnh bdng each ghi phd hdp thy UV-VIS tren may UV245D-Shimadzu (Nhgt Ban)
3 KET QUA VA T H A O LUAN
3.1 Mpt so dac tinh chii yeu cua san pham bpt TiO: dieu che dugc
Mau Ti02 khdng bicn tinh va mlu Y-Ti02 d ty
Ip moi Y/Ti02 0,168% sau khi dieu che dugc tien hanh ghi nhieu xg tia X Gian do XRD cua chimg dugc dua ra d hinh 1 Ket qua tinh loan kich thudc hat trung binh cho thdy, mau Ti02 khdng bign tinh
cd kich thudc hgt trung binh (~ 7,3 nm) Idn hem so vdi mau Y-Ti02 (6,1 nm)
Hinh J: Gian dd XRD ciia mau Y-Ti02 va mau Ti02
khdng bien tfnh Ket qua nay cung phu hgp khi chung tdi tien hanh ghi dang nhiet hap phu-giai hap phy N; (BET) Ket qua BET cho thay, mau Ti02 khdng bien tinh cd dien tich be mat rieng (218,9 m'/g) be han so vdi mau Ti02 (223,6 m^/g) Anh TEM cua mau Y-Ti02 d ty le moi Y/Y-Ti02 0,168% dugc dua ra d hinh
2 Hinh 2 cho thay, mau Y-Ti02 cd kich thudc hat be (- 6-7 nm) va phan bd kha ddng deu
k^^j
Uii4&,i»-Hinh 2: Anh TEM ciia mau Y-Ti02 d
tylp moi YATiOj 0,168%
Trang 3TCHH.T 50(6),2012
3.2 Khao sat mgt so yeu to anh hirong den qua trinh
phan huy paraquat (PD) tren bgt Y-Ti02
3.2.1 Xac dinh thai gian can bSng hip plw - giai hdp
Thuoc trir co Niainaxon 20SL mua tren thj
trudng CO nong dp PD ghi Ihco nhan lii?u 14 200 g/l
Chung toi sir dung phuang phap s5c ki long lii?u
nang cao (HPLC) tiii Vi?n Kicm nghipm an loan v?
sinh thirc phjm quoc gia de xac djnh l?i nong dp PD
Phuong phap xac dinh PD dirpc dira tren TCVN
(2010) do Vien Kicm nghifm An toan V? sinh thirc
pham Quoc gia bicn soan, bp Y tc dc nghj, Tong cgc
Tieu chuSn Do luong Chat luong tham djnh Bo
Khoa hpc va Cong nghp cong bo Ket qua Ihu dupc
n6ng dp thirc eiia PD la 259 g/l Nong dp nay, dupc
chung toi pha loang thanh cae nong dp can thiet cho
nhiing nghien ciru tiep theo
De xac djnh thcri gian dgt can bang hap phu
-giai hdp PD tren bgt Y/TiO; chimg toi thay doi thcri
gian hap phu tir 0 d£n 90 phiit va giir co dinh cac
lupng: Y/TiO, 0,3 g, nong dp PD 19 mg/1 (pH - 7)
Dung lugng hap phu PD tren bpt Y/TiOi duge xac
djnh thong qua bieu thire:
la nong dp t?i thai di^m t ciia chat bj hap phy (mg/1)
va m la lirpug chat hap phy (g) Nong dp PD con Iji sau khi bi hap phy dypc xac djnh bang each do dj hap thy quang (Abs)
Cac thong so hap phy ciia v^t li?u Y/Ti02 dugt trinh bay cr bang 1 Do thj bieu dien sy phy thu^c giita dung lugng va thdi gian hap phy dugc dua rao hinh 3 Ket qua eho thay, khi tSng din thtri gian hap phy dung lugng hap phy tang Qua trinh hap phy xay
ra nhanh eh6ng trong khoang 30 phiit dau tien, sau
do toe dp hap phy cham l^i va gan nhu can bang tai thcri diem 30 phiit Tuy nhien, de dam bao can bang dugc thiet lgp hoan tpan eac thi nghi?m ti6p theo duge chimg toi giii eo djnh thai gian hap phy 60 phut
Q, = V(Co-C,)/m (1)
Trong do,
(nig/g); V
Co la nong
Qi la dung lugng hap phu tgi thdi diem t
la th^ tich dung dich chat bi hap phu (I);
dp ban dau ciia chat bi hap phu (mg/1); Ci
Thdi Kill ^P Phu> P'lut
Hinh 3: Dd thj bieu dien sir phu thupc
giira dung lugng va thdi gian hap phu
Bdng !: Cac thdng sd hap phu PD tren bpt Y-Ti02
Ki hieu
mau
PDO
PD15
PD30
PD45
PD60
PD90
Thcri gian
hap phu,
phiit
0
15
30
45
60
90
Lugng TiO,,
g 0,3 0,3 0,3 0,3 0,3 0,3
The tich dung dieh, 1
0,2 0,2 0,2 0,2 0,2 0,2
Nong dp Co cua PD, mg/1
19
19
19
19
19
19
N6ng dp
C, cua PD, mg/1
19 13,40 11,46 11,38 11,36 11,35
Dung lupng hap phu Qi, mg/g
0 3,733 5,026 5,080 5,093 5,100
3 2-2 Anh hirdng ciia lugng bgt Y-TiO}
Bpt Y-Ti02 dugc cho vao 200 ml dung djch thuoc
trir cd cd ndng dp PD 19 mg/1 vdi cac lugng thay ddi tir
0,10 den 0,35 g Dung djch huyen phu sau khi khuay
60 phut trong bdng tdi dugc tien hanh chieu sang trong
3 gid Phd UV-VIS ciia dung djch PD sau khi phan
huy d cac lugng bpt Y-Ti02 khac nhau dugc thS hi$n d
hinh 4 Tir hinh 4 cho thay, khi tang dan lugng bpt
Y-TiOj tu 0,1-0,15 g thi dp hap thy anh sang cua dung dich PD sau khi phan hiiy giam manh Dp hap thy nay ti^p tyc giam nh? khi lugng Y-Ti02 trong khoang 0,15-0,3 g Neu ti^p tyc tang lugng bpt Y-TiOa > 0,15-0,3 g thi
dp hap thy anh sang ciia dung dich PD cd xu hucmg tang
cac gia trj nong dg dung djch PD trudc (Co) va sau (C) khi phan huy va hi?u suat phan huy quang
Trang 4eho thSy, khi tang dan lugng Y/TiOj tit 0,1-0,15 g
HSPHQ tang m?nh HSPHQ tiSp tyc tang nh? khi
tang dan lupng hot Y-Ti02 va dgt gia tri eye dai irng
voi mlu CO lut^g Y-Ti02 la 0,3 g Neu tiep tyc tang
lugng Y/TiO; > 0,3 g thi HSPHQ co xu huong giam
(do hi$u irng ehan sang)
Bang 2: Anh hucmg eiia lugng bpt Y-Ti02 den
HSPHQ dung tijch PD
Ki hieu mau
PDTiOAlO
PDTiO20,15
PDTiO20,20
PDTiO20,25
PDTiO20,30
PDTiO20,35
Co, mg/1
19
19
19
19
19
19
C,mg/I 2,38 1,45 1,42 1,34 1,29 1,30
H,%
87,47 92,37 92,53 92,95 93,21 93,16
Hinh 4 Phd UV-VIS ciia dung dich PD sau khi bi
phan huy d cac lugng bpt Y-TiOj khac nhau
3.2.3 Anh hudng ciia nong do PD
Nham xac dinh ndng dg PD thich hgp cho qua
trinh phan hiiy, thudc trir cd Nimaxon dugc hda tan
vao dung mdi nudc sao cho dung dich thudc trir cd
dgt dugc d cac nong dp PD khac nhau: 9, 14, 19, 24
va 29 mg/1 Cac d\h\x kien cd djnh khac bao gdm: 0,3
g bdt Y-Ti02, hap phu trong toi 60 phut va chieu
sang dung dich huy^n phii trong 3 gid Ndng dp
dung dich PD sau khi phan huy dugc xac dinh bang
each ghi phd hip thu UV-VIS Pho hap thy UV-VIS
cua dung djch PD sau khi phan hiiy irng vdi cac
ndng do PD ban dau khac nhau dugc dua ra d hinh
5 Tir hinh 5 cho thay, khi tang dan ndng dp PD dp
hap thu anh sang cua cac mau tang Di6u nay chirng
td rang ndng do ban dau ciia PD cang ldn thi
HSPHQ cang giam
cac gia tri nong dp PD trudc va sau khi phan
hiiy va HSPHQ dugc trinh bay trong bang 3 Bang 3
cho thay, khi tang dan ndng dg PD thi HSPHQ giam
Theo Carp O [7], toe dp phan hiiy cac chat hiru co thudng the hi?n dgc diem bao hda Hang so tdc dp thu dugc giam lien tuc ciing vdi su gia tang ndng dp chat d nhiem hiiu co ban dau Carp O, cho rang, cac budc chinh trong qua trinh QXT xay ra tren be mat cua chat ran QXT Do lai ndng dp ban dau cao tat ca cac vj tri xuc tac da bao hda nen sir gia tang hon nira nong dp chat huu co ciing khdng anh hudng den ndng dp be mgt chat xiic tac va do do, cd the dan den lam giam hang so tdc dp phan hiiy Tuy nhien, trong khoang nong dg PD tir 19-29 mg/1 thi HSPHQ van cao (dao dpng khoang 90-93%) Vi vay, de thuan lgi cho nhirng nghien cim tiep theo chiing tdi chpn ndng dp PD
la 19 mg/1
::
1 A
P01D
_ „
Hmh 5: Phd UV-VIS ciia dung djch PD sau khi bi
phan hiiy d cac ndng dp PD ban dau khac nhau
Bdng 3 Anh hudng ctia ndng dp PD ban dau den
HSPHQ dung djch PD
Ki hieu mau PDIO PD15 PD20 PD25 PD30
Co, mg/1
9
14
19
24
29
C,mg/I 0,46 0,95 1,43 1,47 1,90
H,% 97,58 95,00 92,47 92,26 90,00
3 2.4 Anh hudng mdi irudng pH ciia dung dich PD
De khao sat anh hudng ciia pH dung djch PD den qua trinh phan hiiy QXT, 0,3 g bdt Y-T1O2 dugc cho vao 200 ml dung djch thudc trir cd cd ndng dp
PD 19 mg/1 Dung djch PD dugc dieu chinh pH (bang HCl va NaOH) d cac gia tri khac nhau: 4, 6, 7,
8 va 10 Huy6n phii PD va TiOi dugc chieu sang trong 3 gid Pho UV-VIS ciia dung djch PD sau khi phan hiiy cua cac mau d cac gia trj pH khac nhau dugc dua ra d hinh 6 Tti hinh 6 cho thay, khi tang dan gia trj pH thi dp hap thu cua dung dich PD sau khi phan huy giam Dilu nay chirng td, HSPHQ tang ciing vdi vi?c tang cac gia trj pH
Trang 5T C H H , T 50(6), 2 0 1 2
LTinh 6: Phd U V - V I S ciia d u n g djch P D sau khi phan
hiiy d cac gia trj P H d u n g djch P D khac nhau
H S P H Q ciia cac m l u d cac gia Irj pH thay doi
d u g c trinh bay trong b a n g 4 T u b a n g 4 cho Ihay, khi
tang dan gia tri pH thi H S P H Q lang T h e o Hoffmann
[2], cac nhdm hydroxyl tren b6 mat T i 0 2 ton tgi can
b a n e axil - b a z o n h u sau:
> T i O H j <
-> T i O H < - ^
> > T i O H + H" (1)
• > T i O ' + H* (2)
Tir cac p h u a n g trinh (1) va (2) nhan thay, khi
tang dan gia trj p H can b a n g se chuyen djch theo
chieu tang tich dien am tren be mat T i O j (>TiO')
K^t qua nay tao digu kien thuan Igi cho viec hap phu
PD* va do dd lam tang kha n a n g phan hiiy PD"" tren
be mat T i 0 2
Bdng 4 Anh h u d n g mdi t r u d n g p H cua d u n g djch
Ki hieu mau
PDH4
PDH6
PDH7
PDH8
PDHIO
Co, mg/1
19
19
19
19
19
C,mg/1 2,41 1,63 1,46 0,90 0,60
H,%
87,31 91,42 92,31 95,26 96,84
3.2.5 Anh hudng cua thdi gian phdn hiiy
D e k h a o sat a n h h u d n g c u a thdi gian phan hiiy, 0,3 g c h o mdi logi bgt; T i 0 2 k h d n g bien tinh va
Y-T i 0 2 d u g c c h o v a o 2 0 0 ml d u n g djch thudc trir co co
n o n g dp P D 19 mg/1 ( p H ~ 7) D u n g djch huyen phu
d u g c khuay 6 0 phiit t r o n g b d n g toi de dat can bang hap phy - giai h a p va sau d d d u g c chieu sang vdi cac thdi gian thay d o i tir 1 d e n 4,5 gid C a c thdng s6 cho
q u a trinh p h a n hiiy d u n g d i c h P D tren cac mau bot:
T i 0 2 k h d n g bien tinh va Y - T i 0 2 d c a c khoang thai gian p h a n hiiy k h a c nhau d u g c trinh bay trong bang
5 D o thj bicu di£n s\r phy t h u p c giiia HSPHQ va thdi gian phan phan hiiy ciia mau T i 0 2 khdng bl^» tinh va m a u Y - T i 0 2 d u g c d u a ra d hinh 7 Tir bang 5
va hinh 7 c h o t h a y , khi t a n g thdi gian phan huy thi
H S P H Q cua c a c mau t a n g Mlu Y - T i O i cd HSPHQ
c a o h a n so vdi m l u T i 0 2 k h d n g bien tinh d cac
k h o a n g thdi gian p h a n hiiy t u a n g irng Pho UV-VIS ciia d u n g djch P D sau khi bj phan hiiy d cac khoang
thdi gian tir 2,5-4,5 g i d tren m a u bpt Y-Ti02 iu(}c
d u a ra d hinh 8 Tir hinh 8 c h o thay, khi cang keo dai thai gian phan hiiy thi d g h a p thy q u a n g cang giam
P D trong d u n g djch t h u d c t r u cd gan n h u bj phan hiiy hoan loan sau 4,5 g i d c h i e u sang
Hmh 7: D o thj bieu dien s g phy thupc gi&a HSPHQ
va thdi gian p h a n hiiy ciia c a c m l u : TiO^ khong biSn
t i n h v a Y-T1O2
\
X
1 1.0 1.1 2.0
inx]
^~^-.^>
^ ^ — * N ^ _ ( 2 | 1.1 ID 11 (.0 1.1 l
Bang 5: Cac thong so cho
Mau
Ki hieu
mau
PDl,Oh
P D I , 5 h
PD2,0h
PD2,5h
PD3,0h
PD3,5h
PD4,0h
PD4,5h
Tph,
h
1,0
1,5
2,0
2,5
3,0
3,5
4,0
4,5
qua trinh phan hiiy PD tren bpt T i O ; va
T i O ; d u p c bien tinh Y(Ill)
Co, mg/1
19
19
19
19
19
19
19
19
C, mg/1
5,72 4,24 3,14 1,90 1,50 1,22 0,61 0,48
lnC/C„
-1,200 -1,500 -1,800 -2,300 -2,538 -2,744 -3,440 -3,687
H,
%
69,89 77,68 83,47 90,00 92,11 92,31 96,79 97,47
Y - T i O ; cr cac thoi gian pi an huy khae nhau
M l u T i 0 2 k h o n g d u g e bien tinh
Ki hipu mau
0 T i l , 0 h
0 T i l , 5 h 0Ti2,0h 0Ti2,5h 0Ti3,0h OTi3,5h 0Ti4,0h 0Ti4,5h
TpK,
h
1,0 1,5 2,0 2,5 3,0 3,5 4.0 4,5
Co, mg/1
19
19
19
19
19
19
19
19
C , m g / I
12,20 10,35 9,50 8,94 8,37 7,06 6,44 6,00
InC/Co
-0,443 -0,607 -0,693 -0,754 -0,820 -0,990 -1,082 -1,152
H,%
35,79_ 45,52 50,00_ 52,9i_ 55,95
66,10_
6 8 ^
Trang 6Hinh 8: Phd UV-VIS ciia dung djch PD sau khoang
thdi gian phan huy tir 2,5-4,5 gid
Theo cdng trinh nghien cuu [8], qua trinh phan
buy QXT cac hgp chat huu co cd the dugc dac
trimg bang phuang trinh dpng hgc
Langmuir-Hinshelwood nhu sau:
- ^ = k.e = k J i ^
dt 1 + KC
(2)
Trong dd, k la hang so toe dp thyc, K la hang sd hap
phu, t la thdi gian va C la ndng do chat d nhiem hiiu
CO Vdi ndng dp ban dau thap ciia nhung chai d
nhiem hiJu ca, nhdm KC trong mau sd phuong trinh
(6.3) cd the bd qua va tdc dp oxi hda QXT dugc dac
trung bang phuong trinh dpng hpc bac mpt:
Nguyen Vdn Hung vd cgng su Theo quy chuAn ky thuat qudc gia \'i chat lugng
nudc mgt (QCVN 08; 2008/BTNMT) thi ham lugng
PD cd mat trong nudc khdng dugc phep vugt qua 0,9 mg/1 Nhu vgy, vdi lugng chat QXT la 0,3 g, ndng dg PD 19 mg/1 (Idn hon quy chuan cho phep khoang 21 lan) va sau 4 gid chi6u sang thi ham lugng PD trong thuoc trir cd sau khi phan hiiy da thap han ngudng cho phep
4 KET LUAN
Da xac djnh dugc cac dieu ki?n thich hgp cho qua trinh phan hiiy hogt chat PD cd trong thudc
tru-ed tren bpt nano Y-Ti02 dugc dieu che bang phucmg phap thiiy nhi|t Di^u kien thich hgp cho qua trinh phan hiiy nay bao gdm: thdi gian dat can bang hap phy-giai hap 60 phiit; lugng bpt Y-TiOi la 0,3 g/ 200 ml dung djch thudc trir co cd ndng dp PD
19 mg/1; pH dung djch PD ~ 7-8 va thdi gian phan hiiy khoang 4 gid Vdi cac dieu kien nay, thi ham lupng PD cdn Igi trong dung djch sau khi phan buy dat thap hon ngudng cho phep (0,9 mg/1) Dieu nay cho thay kha nang dng dung tdt ciia bpt Y-Ti02 trong xir li paraquat va cac chat d nhiem hiru ca khac Ngoai ra, nghien cuu cdn cho thay bpt Ti02 dugc bien tinh bdi Y(lll) cd boat tinh quang xuc tac cao hon so vdi mau Ti02 khdng dugc bien tinh
Trong dd, k' la hang sd tdc dp bieu kien, cung dugc
biet nhu la hang so tdc dp gia bac mpt va Co la ndng
dp chat hiru ca ban dau
Dd thi bieu dien sy phu thudc giua InC/Co va
thdi gian phan hiiy dung djch PD ciia mau Ti02
khong bien tinh va mau Y-Ti02 dugc dua trong
hinh 9 Tir hinh 9 thu dugc cac gia tri hang sd tdc dp
phan ung ciia cac mau Ti02 khdng bien tinh va
Y-TiOj lan lugc la 0,197 va 0,718 h"' Nhu vgy, cac
mlu Ti02 dugc bien tinh bdi Y(III) cho thay hogt
tinh QXT cao hon nhilu so vdi mau Ti02 khdng
bi6n tinh
,
'
•
r^^^-^-^E;
^•.x"-°""
— iL_(i
1.Ti02
2 Y-TIO2
' ^ S ! '
Hinh 9: Do thi bi^u diln sy phy thupc giira InC/Co
va thai gian phan hiiy cua cac mau Ti02 va Y-Ti02
Ldi cam ffn: Cong trinh ndy duac su ho trg kinh phi tir di tdi md so B20IJ-20-01 cua Bg Gido Due
vd Ddo Tgo
TAI LIEU THAM KHAO
1 K Ekkachai, G Nurak, T Raumpom, N Arthit
Degradation of paraquat under visible light over fullerene modified V-T1O2, Reac Kinel Mech Cat,
103,227-237(2011),
2 Michael R Hoffmann, Scot T Martin, Wonyong
Choi, and Detlef W Bahnemann Environmental Applications of Semiconductor Photocatalysis,
Chem Rev., 95, 69-96(1995)
3 T L R Hewer, E C, C Souza, T S, Martins, E N
S Muccillo, R S Freire Influence of neodymium ions on pholocalalylic activity of TiO; synthesized by sol-gel and precipitation methods, Journal of
Molecular Catalysis A: Chemical, 336, 58-63 (2011)
4 X Yan, J He, D G Evans, yv Duan, Y Zhu
Preparation, characterization and pholocalalylic actrvity of Si-doped and rare earth-doped T1O2 from mesoporous precursors Applied Catalysis B:
Environmental, 55,243-252 (2005)
5 D Xu, L Feng, A Lei Preparation of r/Oj
Trang 7characterizations, Materials Letters, 62, 3297-3300
(2008)
6 Ng6 Sy Luong, Nguyen VSn Hung Anh hudng cua
Y den cdu triic linh the va linh chdt quang xiic Idc
cua bpt Y-Ti02 kich thudc nano dieu che bdng
phuong phdp thuy nhi^t, Tgp chi H6a hpc, 49(3A),
337-342(2011)
7 O Carp, C L Huisman, A Rcllcr Photoinduced
reactivity of titanium dioxide Progress in Solid Stale
Chemistry, 32, 33-177 (2004)
Liu WenXiu, Liu Qing, Li XiuFang, Song YunTing
& Cao WenBin Photocatalytic degradation of coking wastewater by nanocrystalline (Fe N) co-doped TiO} powders, Sci China Tech Sci., 53,
1477-1482(2010)
Lien h(': Nguyen VSn Hung
Khoa Hda hgc, Trudng Dgi hgc Dong Thap
Trudng Dgi hpc Ddng Thap, 783 - Phgm 1 liru Lau, P6, TP Cao Lanh, Dong Thap
Email: nguyenvanhung.chcm@gmail.com