Nghiên cứu xử lý các hợp chất hữu cơ khó phân hủy sinh học trong nước thải bằng các phương pháp oxy hóa cấp tiến

DAI HOC QUOC
GIA
HA
NOI
TRirONG DAI
HOC
KHOA
HOC
TV NHIEN
NGHIEN
ClTU
XLT
LY
CAC
HOP CHAT
UlfU
CO
KHO PHAN HTJY
SINH
HOC TRONG
NlTOC
THAI
BANG CAC
PHUONG
PHAP OXY HOA CAP TIEN
MA
SO:
QT-06-42
CHU
TRI:
ThS.

GVC.
DONG KIM LOAN
cAC
CAN
BO THAM GIA:
- Nguyen Thi Ha TS. GV
- Luu Minh Loan ThS. CBNC
- Phan Mai Linh CN. CBNC
- Nguyen Quang Huy CN. CBNC
- Nguyen Thi Xuan CN. CBNC
- Mot so sinh vien Khoa Moi
truong
va can bo So KHCN&MT Ha Tay,
Thai nguyen.
HA NOI 2006
OAi HOC OUOC GlA
HA
N^,
1.
Ten
de
tai:
Ma so: QT-06-42
Tieng
Viet: Nghien
cuu xu ly
cac hop chat
hiiu
co kho phan huy sinh hoc trong
nirac

thai bang cac
phuong
phap oxy hoa cap tien.
Tieng
Anh\
Investigation for treatment of refractory organic compounds in the
wastwater by advanced oxidation processes.
2.
Chu
nhiem
de tai:
Hoc vi: ThS. GVC
Tel:
8213847/0904700062
Cac can bo tham gia de tai:
-
Nguyen Thi Ha
- Luu Minh Loan
- Phan Mai Linh
- Nguyen Quang Huy
- Nguyen Thi Xuan
Dong Kim Loan
Dan vi
cong
tac: Khoa Moi truong
TS.
GV
ThS.
CBNC
CN.

CBNC
CN.
CBNC
CN.
CBNC
- Mot so sinh vien Khoa Moi truong va can bo So KHCN&MT Ha Tay,
Thai nguyen.
BAG CAO TOM TAT DE TAI
TEN DE TAI
Nghien cuu
xir
ly cac
hap
chat hiru ca kho phan huy trong
nw&c
thai
bang
cacphuffngphdp
oxy hoa cap tien.
Ma
sd:
QT-06-42
CHU TRI DE TAI:
Dong Kim Loan
Dan vi cong tac: Khoa Moi truong
Hoc
vj:
ThS. GVC
Tel:
8213847/0904700062

CAC CAN
BO
THAM
GIA
DE TAI
- Nguyen
Thj
Ha
- Luu Minh Loan
- Nguyen Thj Mai Linh
- Nguyen Quang Huy
-Nguyen thi Xuan
TS.
GV
ThS.
CBNC
CN.
CBNC
CN.
CBNC
CN.
CBNC
- Mot so sinh vien Khoa Moi truong va can bo So KHCN&MT Ha Tay,
Thai nguyen.
MUC TIEU
NGHIEN
CUU:
- Phan
loai
cac chat

huu
co kho phan huy sinh hoc va tim hieu cac bien phap da
ap dung de
xii
ly
nuoc
thai co ham
lugng
chat huu co
cao,
kho phan
hiiy
sinh
trong nuoc va tren the
gioi.
- Ap dung
thir
mot so phuong phap oxy hoa cap tien de xu ly chat huu co kho
phan huy sinh hoc.
- Che tao
xiic
tac quang hoa
Ti02
cho xu ly nuoc thai chua nhieu chat
hiru
co
kho
xir
ly sinh hoc.
NOI

DUNG
NGHIEN CUU:
- Thu thap tai lieu
- Nghien cuu, xu ly
4-clorophenol
bang tac nhan Fenton
- Nghien cuu che tao xuc tac hat
TiO?
tren mot so chat mang
- Nghien cuu
ch^
tao mang xuc tac quang hoa
Ti02
tren mot so nen
(xuoTig/phoi)
khac nhau.
- Nghien
curu
xu
ly
nuoc thai det nhuom bang xuc tac quang hoa
TiO?
/UV
CAC KET QUA DAT
DlSOC:
- Hai
thiSt
bi nghien cuu da
dugc
thiet ke va lap dat phuc vu cho cac nghien

cuu cua
6k
tai
la
thiet bi xu
ly
tuan hoan nuoc thai c6 den tu ngoai va mot
thiet bi xu ly mang
Ti02
/UV.
- Mot bo phan ung de nghien cuu phan ung Fenton
- Da che tao dugc mot so vat lieu mang
Ti02
va mang
Ti02
cho xu ly chat thai
-
Da xay dung dugc quy trinh cong nghe phu hgp cho viec
xir
ly nuoc thai det
nhugm
- Da cong bo 02 bai bao trong Proceedings ve "New trends in technology
towards sustainable development", RSCE 12/2005 va Tap
chi
Khoa hgc-
Khoa hoc tu nhien va cong nghe, T. 22 (3B), 2006.
- Hai khoa
luan
cu nhan nganh Cong nghe moi truong
TINH HINH KINH

PHI CUA DE TAI:
De tai da thuc hien cac chi
phi
the hien tren bang duoi va da tien hanh
thanh quyet toan
voi
Phong Tai vu nha truong
truoc
ngay
31
thang
12
nam 2006.
stt
I
2
3
4
5
6
Danh muc chi
•
Dung cu, hoa chat nghien cuu
Hgp dong NCKH ve
"Nghien
cuu xu ly chat huu ca
kho phan
hiiy
sinh hgc bang tac nhan
Fenton"

Hgp dong NCKH "Che tao mang
Ti02
cho xu ly
moi
truong"
Hgp dong NCKH ve
"Nghien
cuu su dung xuc tac
Ti02
the
lo
lung va mang
Ti02
de xu ly nuoc thai
det nhugm"
Photocopy, in an tai lieu
Thanh toan tien
dien,
nuoc va co so vat chat
>
Thanh tien
4.250.800
2.600.000
2.600.000
3.000.000
169.200
600.000
Muc
•
119/01

114/06
114/06
114/06
119/03
109/01
1
7
8
9
4
5
-
_
_ ,
Van
phong
pham
Hoi thao-cac bao cao vien
Hoi thao-cac
dai
bieu
Quan ly phi
Tong chi phi
100.000
400.000
680.000
600.000
15.000.000
110/01
112/02

112/99
119/99
XAC
NHAN CUA BAN
CHU NHIEM
KHOA
XAC
NHAN CUA
TRUCING
CHU TRI DE TAI
^^T
"^ '^^^^
HO
HIEU
TtUONG
^^s.isM^SLM.
'^<ya/nt
THE SUMMARY OF THE REPORT
Project Title:
Investigation for treatment of biorefractory organic compounds in
wastewater by advanced oxidation processes.
Main Responsible Person/Author:
Master Science Dong Kim Loan, Senior Lecturer
Combained Responsible Persons/Coordinaters:
- Dr. Nguyen Thi Ha
- MSc. Luu Minh Loan
- BS. Phan Mai Linh
- BS. Nguyen Quang Huy
- BS. Nguyen Thj Xuan
- Some Students and Experts in Environmental Technology

The Target of the Project:
-Classifying and studying the applied methods to treat wastewater of
concentrated and biorefractory organic compounds in Vietnam and over the
world.
-Trying several advanced oxidizing processes for treatment of refractory organic
compounds.
-Preparation of some
Ti02
photochemical catalysts for treatment refractory
organic compounds.
Abstract of the content:
-Collecting the documents.
-Investigation and treatment of
4-chlorophenol
by Fenton reagent
-Preparation of
Ti02
granulated catalysts on any support
-Preparation of thin films of
Ti02
on different solid matrixes
-Investigation for treatment of dye wastewater by
Ti02
photochemical catalysts
The results:
Science and Technology:
-Two full-scale systems were designed and installed for treatment of wastewater
by photocatalytic of the project. There is a circulating wastewater system and
ultraviolet light in there instrument.
-A set of reactor for Fenton reaction

-Some granulated
and
thin films
ofTi02
were Prepared for treatment waste.
-A suitable technical model was supposed for treatment dye wastewater
Traning:
-02 Bachelor's Graduated Thesis
Publication:
-02 Published articles in Proceedings concerning "New trends in
technology towards sustainable development", RSCE 12/2005 and Journal of
Science - Natural Sciences and Technology, T. 22, No. 3B AP, 2006
BAO CAO CHI
TIET
KET QUA DE TAI
MUC LUC
Loi
noi dau 1
1.
Modhu
2
2.
Cac chat huu
cokho
phan huy sinh hoc va cong nghe xu ly 2
3.
Qua trinh oxy hoa cap tien va
kha
nang ung dung 5
4.

Nghien cuu loai bo cac
hgp
chat co
clo
bang tac nhan phan ung
Fenton
16
4.1.
Xay dung thiet bi va cac dieu kien nghien cuu
16
4.2.
Ket
qua nghien cuu va thao luan
17
5.
Nghien cuu che tao xuc tac
Ti02 18
5.1.
Che tao vat lieu hat mang
Ti02
19
5.2.
Chi
tao mang
Ti02
20
6. Xu ly nuoc thai det nhuom voi cac vat lieu
xiic
tac da che tao 23
6.1.

Xu ly nuoc thai det nhuom bang he
xiic
tac hat
Ti02/UV
25
6.2. Xu ly nuoc thai det nhuom tren he
xiic
tac mang
Ti02/UV
30
6.3.
So sanh hieu qua xu ly tren hai he
Ti02
va de xuat day chuyen
cong nghe xu ly nuoc thai det nhuom 32
7.
Ket luan va kien
nghj
34
Tai
lieu
tham khao
35
L6I
NOI DAU
Bao ve, duy tri va gin
giii
nguon tai nguyen nuoc la nhiem vu cua tat ca
cac quoc gia tren toan the gioi. Trong do viec tim kiem cac giai phap
hiiu

hieu
nham loai bo cac chat 6 nhiem ben, doc hai va kho phan huy sinh hoc trong nuoc
va nuoc thai da tro thanh thach thuc voi cac nha khoa hoc. Cac qua trinh oxy hoa
cap tien (advanced oxidation processes) dang thu hut su tap trung nghien cuu cua
nhieu nha cong nghe va cac hang ban thiet
bj
xu ly moi truong vi kha nang lam
giam thieu va loai bo cac chat 6 nhiem loai nay.
De tai "Nghien
ciiu
xu ly cac
hgp
chat
hiru
co kho phan huy sinh hoc trong
nuoc thai bang cac phuong phap oxy hoa cap tien" co ma so QT - 06 - 42 dugc
thuc hien duoi su ho trg kinh phi cua Dai hoc Quoc gia Ha noi.
Xin cam on su cong tac ho trg va giup do cua Bo mon Ky thuat nuoc va
nuoc thai, Khoa Cong nghe moi truong; Bo mon Vat lieu v6 co, Khoa Cong
nghe hoa hgc Truong Dai hgc Hoa Ky thuat Praha, Cong hoa Sec.
Cam on su tao dieu kien cho lam viec, cong cu phan tich cua Phong thi
nghiem Cong nghe Moi
truong.
Bo mon Cong nghe hoa hoc, Khoa Hoa hoc
Truong Dai hgc Khoa hoc Tu nhien DHQG Ha noi.
Cam on su cong tac giup do cua Trung tam Nghien cuu, Quan trac va Mo
hinh hoa moi truong Truong Dai hgc Khoa hgc Tu nhien DHQG Ha noi.
Chu tri de tai
TS.
GVC. Dong Kim Loan

L
M&dau.
Mot trong
nhiJng
dang 6 nhiem nuoc pho bien la 6 nhiem nuoc do cac hgp
chat
hGu
co gay ra. Nguon gay 6 nhiem nay kha da dang, trong do chu yeu la
chat thai
tir
cac khu dan cu, cong nghiep, san xuat hoa chat va nong nghiep. Dua
vao kha nang phan huy sinh hgc co the chia cac chat huu co gay 6 nhiem thanh
hai loai:
-Cac chat huu co de phan huy sinh hgc: cac chat nay phan
Ion
la cac
protem,
hydratcacbon, chat beo co nguon goc dong vat va thuc vat. Day la cac
chat 6 nhiem chinh co nhieu trong nuoc thai sinh boat, nuoc thai
tir
cac nha may
che bien thuc pham. Cac hgp chat nay chu yeu lam suy giam oxy hoa tan trong
nuoc,
de gay mui hoi thoi kho chiu do phan huy nhanh trong nuoc
-Cac chat huu co kho phan
hiiy
sinh hoc hay chat huu co doc hai la nhung
chat
CO
kha nang uc che cac qua trinh xu ly sinh hoc, gay hieu ung bat

Igi
cho
sue
khoe, gay nguy hai moi truong cho ca, dong vat hoang da hoac mot cau tu
nhay cam nao do cua mot he sinh thai. Da phan
chiing
la cac hgp chat vong
thom, da vong ngung tu, cac co clo, chat mau azo Trong so nay nhieu hgp chat
la cac chat huu co tong hgp dugc phat sinh tu qua trinh san xuat va la nhung san
pham phu (chat thai) khong mong muon nhu dioxin
Noi chung, cac hgp chat
hiJu
co kho phan huy sinh hoc deu co do tan nho
trong nuoc, nhung
lai
thuong c6 mat nhieu trong nuoc tu rat nhieu nguon khac
nhau. Do kho phan huy sinh hgc, thoi gian ton luu
lau
va kha nang tich
luy
sinh
hoc cao nen chi
6
mot nong do thap da gay 6 nhiem
Ion
cho moi truong nuoc.
Chinh
vi vay, tim kiem cac bien phap de xu ly loai bo cac hgp chat nay
luon
la can thiet; song trong thuc te dang con gap nhieu kho khan ve ky thuat

cung nhu gia ca de xu ly. Oxy hoa cap tien la mot huong nghien cuu dugc nhieu
nha khoa hgc tren the gioi quan tam nhat trong
nhiing
nam gan day. Nho
nhiing
tinh chat uu viet cua no va kha nang tao cac vat lieu voi
nhGng
hieu ung nano
hap dan no da tro thanh nganh "hoa hoc cua the ky 21"
[15].
2
Cac hap chat hiru ca kho phan huy sinh hgc
va phirangphdp xir
ly
2.1.
Phan loai
Mot so nhom chat huu co kho phan huy sinh hoc pho bien la:
2.1.1.
Cac hop chat co clo (chu yeu la cac clorophenol)
Cac hgp chat clorophenol la cac dan xuat clo cua phenol bao gom 2-/3-/4-
clorophenol;
2,4-/2,3-/3,4 diclorophenol; 2,4,6-/2,3,5 ,.triclorophenol
cho
den
pentaclorophenol.
Cac hgp chat nay dugc tao ra trong cong nghiep san xuat
chat bao quan, san xuat bgt giay, go, thuoc bao ve thuc vat, san pham cua qua
trinh tay trang bang hgp chat clo, san pham cua qua trinh thieu dot chat thai nguy
hai
4-clorophenol con la chat trung gian trong qua trinh phan

hiiy
cac
clorophenol cao hon va axit
2,4-diclorophenoxy.
Hau het cac hgp chat co clo deu
rat ben vung, doc hai va ton tai lau trong moi truong.
Clorophenol ton tai trong moi truong nuoc duoi nhieu dang: hoa tan
6
trang thai tu do hoac
phiic;
hap phu
Ion
tren cac chat ran lo lung, cac tram tich
hoac nam trong cac mo sinh hoc.
Cac clorophenol co the hap thu vao co the qua
duong
ho hap o dang hoi,
suong; qua da hoac qua duong tieu hoa. 4-clorophenol ciing gay ra nhung bien
doi ve mat sinh hoc doi voi dong vat, anh huong den qua trinh sinh san. 0 nong
do cao pha
hiiy
gan, than, da, kich thich da day. Tat ca cac clorophenol deu co
doc tinh cao voi tao va hau het cac thuc vat
thiiy
sinh. Ca va cac sinh vat
thiiy
sinh hap thu clorophenol qua mang, da va thanh rugt.
Cue
moi truong Lien bang
My (EPA) quy dinh nong do

2,4-chlorophenol
trong nuoc mat khong dugc vugt
qua 2,02
mg/1.
2.1.2. Thuoc nhuom
Nhom cac chat hiiu co su dung trong qua trinh nhuom mau (chu yeu trong
det nhuom va giay in mau) phan nhieu cung la nhiing chat kho phan
hiiy
sinh
hgc.
Cac thuoc nhuom thuong rat ben
vu"ng
trong moi truong, c6 mau dam dac
va kho phan huy do da phan co cau
triic
thom, ngung tu chua cac di nguyen to.
Trong so do cac hgp chat mau azo dugc quan tam nhieu hon ca do khoi lugng
sii
dung
Ion,
ben Mot so thuoc nhuom con gay
lic
che boat dong cua cac vi sinh
vat phan
hiiy
chat
h&u
co. Mat khac do cac chat huu co trong thuoc nhuom
kh6ng"tan
trich"

het hoac khong gan mau vao sgi ma tao ra. Cac thuoc nhuom
khi nhuom co muc do gan mau khac nhau. Ty
le
mau gan vao xo sgi nam trong
khoang 50-98%, phan con lai se di vao nuoc thai lam cho do mau
ciia
nuoc thai
det nhuom luon cao. Thuoc nhuom dugc xep vao doc to nhom 1 va
2,
2.1.3.
Hoa chat trong cong nghiep duoc pham
Nhieu loai hoa chat dung trong cong nghiep dugc pham la nhung
hydrocacbon thom va khong thom co dinh cac nhom chuc va di nguyen to khac
nhau
CO
tac dung dieu tri benh. Cac hoa chat nay da phan la nhung chat co kha
nang sat trung manh, nen rat doc voi he vi sinh vat noi chung va cac vi sinh vat
trong he
xii
ly nuoc thai noi rieng.
Vi
du Woltaren hay con goi la diclophenac
[2-(2,6-dicloroanilino)phenylaxetat natri] la mot loai thuoc giam dau, chong
viem rat pho bien
diing
vao hang dau
ciia
25 loai dugc pham su dung nhieu nhat
tren the gioi va Viet nam, do do du lugng trong moi truong la dang ke. Tuy
nhien voi cong nghe xu ly nuoc hien nay, nhieu cong trinh nghien cuu da cho

thay sau tram xu ly nuoc cap 2 va cap 3 van phat hien
tha}'
chiing o co vai tram
ng/1
den
\x%IV
Vi the chiing thuong dugc loai truoc khi ap dung mot bien phap
sinh hgc nao do de xu ly nuoc thai.
2.1.4. Cac thuoc bao ve thuc vat
Cung tuong tu, chiing la
nhirng
hgp chat
hiiu
co thom hoac beo voi so
nguyen tu cac bon
Ion
trong phan
tii.
Nhom cac chat nay thuong tren co so hgp
chat huu
CO
di vong
chiia
kim loai, halogen, nito, phospho, luu huynh Da phan
cac thuoc bao ve thuc vat la nhiing chat doc cham va kho phan
hiiy
sinh hoc.
Ngoai ra, cac chat
hiJu
co hay dugc xu ly bang AOPs con la cac

hydrocacbon dau mo, cac hydrocacbon da clo hoa dugc su dung lam dung moi
va cac chat lam sach cong nghiep, cac hoa chat quoc phong nhu TNT, RDX va
HMX. Trong nhieu truong hgp hydrocacbon da clo hoa ben doi voi phan
hiiy
bang sinh hgc, nhung lai dugc
xii
ly mot
each
hieu qua nho tac dung
ciia
tia
tii
ngoai khi co mat chat oxi hoa. Dien hinh la cac hgp chat huu co bi oxi hoa de
dang
6
cac vi tri noi doi (TCE, PCE va vinylclorua) cung nhu cac hgp chat thom
(toluene, benzene,
xylen
va phenol) bi phan
hiiy
mot
each
nhanh chong bang cac
qua trinh oxi hoa/UV.
2.2.
Cac
phuang
phap xu ly
thuang
ap dung

Hien co kha nhieu cac phuong phap xu ly cac chat kho phan
hiiy
sinh hoc
nhu thieu dot, chiet long-long, hap phu, keo tu, tham thau ngugc, oxy hoa h6a
hoc,
xii
ly hoa hgc ket hgp voi sinh hoc va oxy hoa cap tien. Tuy nhien, viec
lira
chon phuong phap
xii"
ly cho phu hgp can can
cii
vao luu lugng, nong do chat 6
nhiem, chi phi cho qua trinh xu ly, yeu cau va
miic
do phai xu ly O day tap
trung vao mot so cac qua trinh oxy hoa cap tien vi
nhiJng
ly do sau:
-Doi tugng nghien cuu la cac chat
hiiu
co doc, ben va kho phan
hiiy
sinh
hoc.
-Cac qua trinh oxy hoa cap tien (AOPs) la qua trinh oxy hoa chat
hiiu
co
bang nhiing tac nhan co the oxy hoa
cue Ion

nhu goc OH hoac/va be mat trong
dien tu
(h"^) ciia
chat
xiic
tac, nen c6 kha nang phan huy cac chat
hiiu
co ben.
-Qua trinh oxy hoa xay ra duoi cac dang phan
ling
day chuyen, nen khong
tuan theo phuong trinh ty lugng ma thuang chi can 1 lugng hoa chat nho hon
lugng tinh toan ly thuyet cung co the oxy hoa hoan toan
1
mot lugng chat
hiiu
co
xac dinh. Do do AOPs con co uu diem la tiet kiem hoa chat.
-Co kha nang oxy hoa hoan toan cac chat
hij'u
co den
CO2
va
H2O
trong
hau het cac truong hgp. Vi the khong tao san pham thu cap doc va cung co the
dugc
sii"
dung nhu qua trinh tien xu
ly

de loai bo cac chat doc hoac cac chat ben
vi sinh truoc khi xu ly sinh hoc.
3.
Qua
trinh
oxi hoa cap tien va kha nang ung dung
De khac phuc
nhimg
nhugc diem la
xir
ly rat dat hoac khong triet de
ciia
cac phuong phap khac va de giam gia thanh cung nhu tang hieu qua xu ly cac
chat
hiiu
co doc, ben sinh hoc; nhom cac qua trinh oxy hoa cap tien (advanced
oxidation processes) da ra doi dua tren kha nang tao ra the oxy hoa rat cao cua
tac nhan oxy hoa hoa hoc da su dung. AOPs rat hieu qua trong viec loai bo hang
loat
cac chat 6 nhiem
hiiu
co kho phan
hiiy
nhu cac
fenol,
foocmandehit, cac
chat
hiiu
co de hap thu lien ket voi cac halogen (AOXs), cac chat mau va nhom
cac thuoc tru dich

hai ra
khoi cac nguon nuoc mat ciing nhu nuoc thai.
Ngay nay cac qua trinh oxy hoa cap tien (AOPs) da phat trien theo cac ky
thuat tien tien khac nhau va dugc ggi la cac ky thuat oxy hoa cap tien (AOTs)
theo mot trong hai con duong
[15]
3.
/. Oxy hoa
uat
(wet air oxidation
-WAO)\
co kha nang oxy hoa cac hgp
chat
hiiu
co hoac v6 co trong pha nuoc bang oxy khong khi o dieu kien nhiet do
va ap suat cao. Nhiet do thuong o khoang
150-300^'C
va ap suat tu > 1 - 20 atm
thi hieu qua loai bo COD va mau co the
len
toi tu 65-90%. Cac chat co the xu ly
bang oxy hoa uot thuong la cac chat beo, cac hgp chat vong chua goc axit beo
(ma khong chua cac nhom
chiic
halogen) nhu phenol va anilin [8]. Phuong phap
oxy hoa uot c6 the ket hgp voi bun boat tinh de giam COD
ciia
nuoc thai giau
hiiu
CO.

Tuy nhien do phai thuc hien o dieu kien nhiet do va ap suat cao nen gia
thanh xu ly dat cung nhu thiet bi thuong kho kiem va nguy hiem.
3.2.
Tao goc hydroxyl
Day la nhom cac phuong phap tren co so cac chat oxy hoa hoa hgc thong
thuong nhung bo sung them tac nhan lam tang kha nang oxy hoa trong cac phan
ling
trung gian de phan
hiiy
chat
hiiu
co den
CO2
va
H2O.
Cac qua trinh nay xay
ra do
sir
xuat hien cua cac goc hydroxyl tu do co the dien hoa rat cao. Chinh qua
trinh sinh goc tu do da tao dieu kien phoi hgp cac chat oxi hoa thong thuong nhu
H2O2,
O3
voi
O2
hay ion kim loai hoac voi tia
cue tim
(UV) de tro thanh he
thong
xiic
tac

cue
manh phan
hiiy
chat
hiru
co. Co hang loat cac phan
irng
dan
den viec hinh thanh cac goc hydroxyl: vi
dii
nhu cac phan
ling
cua
O3/UV (HofI
et
al.,
1997),
H2O2/UV,
Fe-7H202
(Fenton oxidation),
Fe-7H202/UV
(Goi,
2002) hay
Ti02/UV
(Arslan
etal,
2000) [16].
Nang
luc
oxy hoa cua mot so tac nhan the hien tren bang sau

[15]
Bang
J.
7.
Nang
luc
oxy hoa
Chat oxi hoa
CI2
03
f
The oxi hoa
1,00
1,52
Chal
oxi hoa
HCIO
0 (ng.tir)
The oxi hoa
1,10
1,78
Chaloxi
hoa
KMn04
'OH
Thcoxi
hoa
1,24
2,05
Chat oxi hoa

H7O,
The
oxi hoa
1,31
Ti02'(h*) 1
2,35
sau:
Kha nang oxy hoa manh me cua goc OH [15]
dugc
minh hoa trong bang
/./
/
o-/
Bang
J.
2.
Hang so toe dp phan
ung
(k,
AT
S")
ciia ozon
so
vm goc
OH
Hgp chat
Chlorinated
alkenes
Phenols
O3

10'- •10^
10'
'OH
lO'^-lO"
10*^-10'"
Goc hydroxyl la mot tac nhan oxy hoa manh, khong chon
loc
voi hau het
cac chat huu co. Hieu qua xu ly chat huu co phu thuoc rat nhieu vao nong do goc
OH sinh ra. De tao cac goc hydroxyl, hai nhom cac ky thuat oxy hoa cap tien
dugc
dua vao la:
3.2.1.
Ky thuat oxy hoa cap tien khong quang hoa (non-photochemical)
Co 4 phuong phap hay dung de tao ra goc OH ma khong can anh sang
quang hoa, bao gom:
* Ozon hoa
6*
pH nang cao
Khi tang pH,
toe
do phan buy
O3
trong nuoc tang. Vi du
6
pH =
10,
thoi
gian ban phan huy
ciia O3

< 1
phiit,
su oxy hoa cac chat huu co xuat hien do su
ket hgp cac phan
li'ng
voi phan
tii*
O3
va cac phan ung voi cac goc OH [5].
Phan ung
giiJa
cac ion hydroxit voi
O3
dan den hinh thanh cac goc anion
peoxit
O2 "
va goc hydroperoxit
HO? ".
Nho phan ung
giiJa
goc anion peroxit voi
ozon, goc anion ozonit
O3
' dugc hinh thanh va phan buy ngay
tire
khac tao goc
OH theo phan
ling:
3O3
+

OH"
+
H"
>
2*0H
+ 4O2
(3.1)
Ion cacbonat va bicacbonat dong vai tro quan trong nhu loai tieu thu goc
OH trong cac he thong tu nhien. Cac san pham phan ung giua chiing la cac goc
cacbonat va bicacbonat mang dien tich duong nen khong tuong tac tiep voi ozon
va chat huu co. Vi the su c6 mat cua mot so anion nhu
HCO3",
CO^^',
S04^'
va
Cr
trong nuoc va nuoc thai khong co
Igi
cho su tao thanh OH. Tuy nhien viec
sir
dung ozon thuong dat do gia thanh dien phan sinh ozon.
* Ozon hoa ket hap vai
H2O2 (O3/H2O2
- phan
i>ng
peroxon)
Viec them
H2O2
vao
O3

co the khoi mao cho chu trinh phan huy ozon sinh
ra goc hydroxyl
[10]
H2O2 >
HO2"
+ W
(3.2)
• 03
+
H02'
>
H02*
+
Oj'"
(3.3)
Phan ung tiep tuc theo con duong khong true tiep da mo ta
6
tren va cac
goc OH dugc hinh thanh. To hgp cac
buoc
phan ung khac nhau cho thay hai
phan tu ozon sinh ra hai goc hydroxyl theo phuong trinh sau
2O3 + H2O2 >
2*0H
+ 3O2
(3.4)
Paillard et al.
[15]
da chung minh rang: to hgp
H2O2/O3

phan
hiiy
thuoc
tru sau tot hon phan buy bang mot minh O3. Ty le khoi lugng
H2O2/O3
toi uu la
0,35-0,45. Hieu suat qua trinh phu thuoc vao lieu ozon, thoi gian tiep xuc, do
kiem cua nuoc.
Theo Duguet et al. [7] thoi diem bat dau dua
H2O2
vao be xu ly rat quan
trong. Hieu suat tot nhat dat dugc khi
H2O2
dugc them vao sau khi da oxy hoa
cac chat co kha nang phan ung cao voi mot minh O3.
R6
rang viec bo sung cac
goc
CO
kha nang oxy hoa cac phan tu kho phan
hiiy
da tao ra Igi the cho phan tu
O3
phan ung chon
Igc
truoc khi c6 su tan cong cua goc tu do khong chon
Igc.
Hydropeoxit la mot chat oxy hoa khong dat va de kiem.
* Ozon hoa co xuc tac (O3/CAT)
Co hoi khac de thuc day cac phan ung ozon hoa la

sir
dung
xiic
tac dong
the va di the. Mot vai he
xiic
tac oxit kim loai va ion kim loai
(Fe203,
Al203-Me,
Mn02,
Ru/Ce02,
Ti02-Me,
Fe"
,
Fe'
,
Mn^"
) da
thiic
day dang ke su phan buy
chat, mac du co che phan ung trong hau het cac truong hgp chua sang to.
Cortes et al [5] nghien cuu kha nang oxy hoa tot cac clobenzen trong nuoc
thai su dung ion sat va mangan nhu nhiing
xiic
tac di the, cho ket luan: dung he
O3/CAT se loai dugc tong cacbon
hiju
co*
(TOC) va nhu cau oxy hoa hgc (COD)
khoi nuoc thai hieu qua

hon
he
O3
hoa
6
pH cao. Cac he
03/Mn(n)
va
03/Fe(lI)
hieu qua hon trong viec loai cac hgp chat co clo so voi he
03/Fe(III)
va
O3
o pH
cao.
He O3/GAC (hat than boat tinh) la mot truong hgp dac biet cua viec ozon
hoa
xiic
tac. Dac biet la kha nang pha buy cau
triic
cac hgp chat ben sinh hoc (vi
du thuoc sau). Su dung GAC nhu mot
xiic
tac tao cac goc tu do trong nuoc da
ozon hoa it dugc nghien cuu va mot vai truong hgp cho ket qua ngugc lai.
Kaptijn
[13]
cho thay, oxy hoa cac chat
\iu\x
co kho phan

hiiy
sinh hgc
trong cot phan ung ozon hoa nhoi day GAC se hinh thanh cac goc
O*',
O2*"
va
O3
"
(chu khong phai goc OH) tren be mat than. Quy trinh nay da dugc thuong
mai hoa tu
1992
voi ozon cung cap la 1,7 kg cho viec loai
1
kg COD.
* He Fenton
Phan ung Fenton
(H2O2/
Fe"^)
rat phu hgp de loai bo mot so chat doc sinh
hgc khong chi vi cac tac nhan
sir
dung re va rat de kiem ma con la nhirng chat
sinh ra sau phan ung khong doc hai va qua trinh
xiic
tac xay ra trong he dong
th^
(Lopez
e/a/.,
2004).
7+

Fe'"
+
Fe'"
+
Fe'"
+
H2O2 ->
Fe^"
+
HO2'
+
HO2*
-^
Fe-" +
O2
+ H"
R'
->
Fe'"
+ R"
Co so cua phan ung Fenton la phan ung cua ion
Fe*"
va hydropeoxit trong
moi
truong
axit
[18],
Phan ung xay ra theo phuong trinh sau:
Fe^^
+

H2O2 ->
Fe^^
+
OH +
OH'
(3.5)
Ion Fe hinh thanh co the tiep tuc phan ung voi
H2O2
de tao goc
hydropeoxyl va chinh qua trinh nay lai tai tao ion
Fe"^.
Qua trinh hinh thanh va
tai tao nay xay ra theo cac phan ung 3.6, 3.7 va 3.8 sau;
H^
(3.6)
(3.7)
(3.8)
r
f
Cac goc hydroxyl hinh thanh (theo phan ung 3.5) se oxi hoa cac chat 6
nhiem theo cac ca che sau:
- Phan ung cong:
OH*
+
CgHft->
(OH)C6H6'
(3.9)
-Dehydrohoa:
OH'+
CH3OH-^

CH20H'+
H.O
(3.10)
- Trao
d6i
electron:
OH'
+
[Fe(CN)6]''"
-^
[Fe(CN)6f"
+
OH'
(3.11)
- Tuong tac goc - goc hydroxyl phan ung voi cac goc tu do khac tao thanh
cac san pham
bSn
hon:
OH' + OH'
^ H2O2 (3.12)
Trong xu ly nuoc thai bang phan ung Fenton, nguoi ta phai co gang tao
dieu kien ban dau sao cho xay ra hai qua trinh theo co che
ciia
phan ung (3.9) va
(3.10) (
CO
che phan ung cong va dehidro hoa).
3.2.2. Ky thuat oxy hoa cap tien quang hoa
Cac phan ung oxy hoa pha
hiiy

hoan toan cau triic
ciia
chat co the dat
dugc
bang each cung cap tia UV, ma khong can ozon hoac hydroperoxit
[15].
De dat hieu qua phan quang
O3
cao, cac den UV phai co cong suat buc xa
cue dai o 254 nm. Nhieu chat ban huu co hap thu nang
lugng
buc xa trong
khoang 200-300 nm va bi phan
hiiy
do phan quang
true
tiep hoac chuyen len
trang thai kich thich va nho the ma phan ung hon voi cac chat oxy hoa. Hien nay
cac den co buc xa
6 172
va 222 nm da dugc san xuat cho phan quang
true
tiep
nuoc,
sinh OH va goc H - rat hieu qua trong cac qua trinh oxy hoa UV [16, 17].
*03/uy
Ozon hap thu thang tia UV o 254 nm (he so tat
8254 nm =
3300
M"'.cm"')

tao ra
H2O2
nhu mot chat trung gian sau do phan tach thanh OH [9]
O3 + hu > O2
+ 0('D)(3.13)
0('D)
+
H2O > H2O2 >
2*0H
(3.14)
San xuat
*0H
theo each nay thuong la dat do den Hg ap suat thap thong
thuong phat sinh > 80% nang lugng UV cua chiing o buoc song nay. Tuy nhien
do do hap thu phan
tii'
gam thap cua
H2O2 6
254 nm
(£254 nm =
18,6
M"'.cm"'),
nen da gioi ban san lugng goc
*0H
trong dung dich (neu dung
H2O2
de tao OH).
Phan quang chi dung
O3
sinh cac goc tu do nhieu hon dung

UV/H2O2
(bang 3.3)
[9,10],
Trong thuc te, nang lugng doi hoi cho den UV trong qua trinh phan
quang
O3
0 co Wat doi ngugc voi co KW cho phan quang
H2O:.
8
Bang
3.3,
Su
hinh thanh *OH tii-phan quang O3 va
HjO:
p
—
Chat oxi hoa
H2O2
O3
£254 nm
M'Vcm"'
20
3300
So
do
H.O.

3O3
-
-—> 2 OH

_„> 2
'OH
'OH
/photon
0,09
2,00
Neu dung dich nuoc chua cac hgp chat hiiu co hap thu manh anh sang
UV, thi them buc xa UV khong lam tang len hieu qua xu ly bang
O3
boi vi cac
hgp chat quang boat nhu phenol,
5-methylresorcinol,
xylenols da hap thu het
tia UV den ozon. Mac du cac hgp chat phenolic (phenol,
p-cresol,
2,3-xylenol,
3,4-xylenol)
bi ozon oxi hoa de dang, nhung su khoang boa cung hiem khi hoan
toan den
CO2
va
H2O.
Su dung he O3/UV, viec khoang hoa hoan toan hieu qua
voi cac hgp chat
hiiu
co c6 mach cacbon ngan (glyoxal, glyoxylic axit, oxalic
axit, foocmic axit).
*
H2O2/UV
Sir

phan quang true tiep bang
H2O2/UV
dan den hinh thanh OH
H2O2
+ ho
>
2
*0H
>
\
r
Dong thoi cung co mot can bang axit-bazo voi
H2O2,
hap thu tia UV
6
buoc song 254 nm.
H2O2
<^
HO2'
+
H'
ho +
H02'
> *OH +
O*"
Qua trinh
H2O2/UV
dugc su dung thanh cong de phan
hiiy
cac

clorophenol va cac hgp chat clo hoa khac nhau. Cac phan
tii"
nhu atrazine,
desethylatrazine va simazine co the bi khoang hoa den tan
CO2
trong thoi gian
buc xa
CO
mat
H2O2.
**03/H202/UV
Them
H2O2
vao qua trinh O3/UV da
thiic
day su phan buy O3 lam tang
toe do sinh *0H. Dac biet trong cac qua trinh ma chat 6 nhiem hap thu yeu tia
UV, thi chi can mot nguon UV nho them
H2O2
se co hieu qua hon.
Bang
3.4.
So
sdnli gia lioat dong ciia
mot
vai qua trinh
AOP
Qua trinh
O3/UV
O3/

H2O2
H2O2/UV
Xuc tac quang oxi hoa
Gia chat oxi boa
Cao
Cao
Trung binh
Rat thap
Gia
nanglugng
Trung binh
0
cao
Trung
binh
> cao
Neu su phan quang cac chat 6 nhiem khong phai la yeu to chinh thi
O3/H2O2
nen dugc can nhac nhu mot su thay the cac qua trinh oxi hoa quang boa.
1 r
Nang
lire
va gia ca hoat dong cho cac he UV/O3 va hoac
UV/H2O2
thay doi rat
rgng phu thuoc vao dong nuoc thai, kieu va nong do chat 6 nhiem co mat va muc
do yeu cau loai bo. Bang 3.4
6
tren so sanh gia ca boat dong
ciia

cac AOPs khac
nhau.
* Quang hoa-Fenton va cac he kieu Fenton
Khi ion
Fe^^
dugc them vao he
H2O2/UV,
qua trinh dugc ggi la oxi hoa
quang boa kieu Fenton.
6
pH 3, phuc Fe(OH) dugc hinh thanh vi moi truong
axit theo phuong trinh:
Fe^"
+ H2O >
Fe(OH)''
+
H"
Fe(OH)^^
^
Fe^^
+ OH'
Cho tiep xuc voi tia UV, phuc bi phan
hiiy
tiep sinh OH va ion Fe
Fe(OH)^^
+
hu >
Fe^^
+
*0H

(3.15)
Ro rang la phan ung kieu quang-Fenton (photo-Fenton type) dua chu yeu
vao tia UV de bat dau sinh OH, neu muon cac chat 6 nhiem hiiu co bj khoang
hoa hoan toan voi cac tia
UVA^IS
[11].
Vi du: mot so chat diet co va tru sau co
the bi khoang boa hoan toan nho qua trinh quang-Fenton. Hieu qua tang len cua
cac tac nhan Fenton/kieu Fenton voi tia
UV/VIS
dugc cho la:
+Khu quang ion
Fe'^
: buc xa cua ion
Fe"^
(va hoac Fe(0H)3 sinh ra
ion Fe theo phan ung
(4.15);
ion Fe da sinh ra tiep tuc phan ung voi
H2O2
sinh
ra mot goc *0H thu 2 va ion
Fe^""
roi chu trinh lai tiep tuc.
+Su
dung hieu qua lugng tu anh sang: pho hap thu cua
H2O2
khong
vugt qua buoc song 300 nm va co he so tat thap ngoai
viing

buoc song 250 nm.
Mat khac, pho hap thu cua ion
Fe^^
(va hoac ion hydroxy sat 3) keo dai den vung
UV gan VIS hoac VIS va co mot he so tat rgng hon, vi vay co the oxi hoa-quang
hoa va khoang hoa tham chi bang anh sang trong vung nhin.
Viec hinh thanh Fe(II) khong phu thuoc vao buoc song buc xa trong
khoang 250-450 nm (UV/VIS) va giam dan neu buc xa co buoc song dai hon.
*
0x1
hoa quang xuc tac
(UV/Ti02)
Co so cua quang
xiic
tac la
sir
kich thich quang cua mot chat ban dan ran
(SC) sau khi hap thu buc xa dien tu. Duoi cac tia buc xa gan UV, mot vat lieu
ban dan
b^n
co the bi nhung photon co nang lugng
dii Ion
kich thich phat ra
electron (e) va nho the hinh thanh nen cac khoang trong electron (ggi la
'Mo
trong
boa tri
h""")
co tich dien duong ao. Nhu'ng phan tu mang dien tich nay (e,
h^)

co
the tao ra kha nang oxi hoa hoac khu hoa. 0 tren be mat
ciia
cac hat
Ti02,
nhiing
phAn
tu nay co the phan ung voi cac loai da hap thu tren do (chang han voi
O2
la
chat
nhan e (A) va OH*,
RCOO"
la
ch^t
cho e (D) )
[15,
16].
Qua trinh nay co
th^
dugc tom
tSt
nhu sau: hv
+
(SC)
^
e'
+
h*;
e"

+
O2 ^ *02
;
h^
+
OH"
-^ *0H
;
h*
+
RH ^
'RH*
-^
cac san pham
10
w
Cac 16 trong
h"^
co the oxi hoa cue ky duong va boi the co the oxi hoa hau
het cac chat boa hgc, tham chi oxi boa mot electron
ciia
nuoc de hinh thanh cac
goc hydroxyl nen rat kha thi ve mat nang lugng.
H2O
+
h^
-> *0H +
H^
Mot chat xuc tac quang hgc tot phai bao gom hai tinh chat: (i) hap thu tot
proton, (ii) hap phu tot cac chat phan ung.

Ti02,
6
ca 2 dang anatase va rutile la mot trong
nhiJng
oxit kim loai dugc
su dung rgng rai nhat trong cong nghiep. Chi so phan xa cao
ciia
no trong vung
anh sang nhin thay cho phep tao ra nhung mang mong va boi the no dugc
sir
dung nhu mot pigment. Mat khac, no cung dugc su dung nhu mot chat mang
xiic
tac hoac nhu mot
xiic
tac va tu quang boa
xiic
tac rat tot.
Ti02
boat dong khong
chi nhu mot chat mang
xiic
tac ma con tuong tac voi pha chat mang nhu mot
chat boat dong.
Ti02
dang anatase co bandgap nang lugng
=
3,2 ev va co the
dugc boat hoa bang
each
chieu tia UV

6
buoc song khoang 300 nm.
Thuc te, tat ca cac loai hgp chat doc hai deu co the bi phan
hiiy
bang tac
nhan oxi boa quang
xiic
tac (PCO). Cac hydrocacbon halogenua bi khoang boa
hoan toan. Cac phan
tii
thom ciing bi oxi boa mot
each
dinh lugng. Cac phenol,
biphenol da clohoa va tham chi dioxin cung bi oxi boa hoan toan sinh
CO2
va
HCl.
Mot bang chung la cac san pham phu doc hai khong hinh thanh tham chi
chi mot lugng vet. Cac thuoc nhugm, cac phthalate, DDT va chat boat dong be
mat cung dugc khoang boa tot boi
xiic
tac nay [4 ].
Chinh vi the, hau het cac boat dong nghien
cii'u
ve
ITnh
vuc
xii
ly chat thai
chiia

cac chat
hiru
co doc hai va ben tren toan the gioi dugc gianh cho PCO.
Ngay nay, PCO va cac AOP khac nhau cung dong vai tro quan trong trong cac
ky thuat xu ly nuoc uong moi
[15].
Dong gop vao viec nghien cuu cac ky thuat oxi hoa cap tien va nghien
ciiu
che tao mang
xiic
tac quang, de tai cua chiing toi dugc tien hanh voi muc dich ap
dung mot so qua trinh AOP de
xii
ly loai bo chat
hiru
co doc hai trong nuoc thai
cong nghiep o Viet nam.
3.3. Kha nang ung dung cac ky thuat oxi hoa cap tien trong
xir
ly
nw&c
va
nu'O'c
thai
Tu tong quan 0 tren cho thay van de kho khan nhat trong thuc te
ling
dung
cac AOP la
lira
chon hoac thiet ke he thong oxi boa hieu qua nhat cho chat 6

nhiem. Boi the, da co mot vai de xuat va mo hinh dugc gioi thieu [7, 8, 13].
Glaze [9] da dua mot mo hinh oxi boa dung
djch
nitrobenzene dam dac
sii
dung
cac
ky
thuat AOP khac nhau nhu:
O3 6
pH
cao,
O3/H2O2,
H2O2
/UV va
O3AJV.
Uu diem va nhugc diem
ciia
moi qua trinh dugc xac dinh. Nghien
ciiu
nay cung
cho thay mot vai gioi ban ung dung AOPs dien hinh cho xu ly nuoc thai dam
dac.
Trai ngugc voi
sir
oxi boa mot vai chat 6 nhiem vi lugng trong nuoc tu
11
nhien (nuoc
ngam,
nuoc qua

trinh
cua chat ban dan ), cac hgp chat huu co
trong nuoc thai c6 nong do tuong doi cao (> 50 ppm) trong
n^n
phuc tap thi kho
khan lai la van de nang lugng va chat oxi hoa.
K^t
qua
thii
vi
nhk
la kha nang
oxi boa nitrobenzene bang ozon ciing dat duoc
gidng
nhu oxi boa voi to hgp la
O3/H2O2
hoac
Or/UV.
Cac he UV va H2O2/UV dugc Tuhkanen nghien
ciiu
chi
ti^t
[10,
16].
Oxi
hoa quang phan naphtalen va PCP bang
biic
xa UV
t6
hgp voi

H2O2
co
t6c
do
oxi boa cao hon va thoi gian song ngan hon cua cac chat huu co so voi chi phan
quang. Qua trinh oxi hoa
H2O2/UV
dugc cho
rSng
do
sir
hoat dong
ciia
cac loai
goc khac nhau (khong chi bao gom goc hydroxyl, ma co le ca
g6c
ion cacbonat).
Hirvonen [10] da nghien
ciiu
tinh kha thi cua viec
xii
ly lam sach nuoc
ngSm
nhiem
bSn
TCE va PCE (TeCE)
bang O3/H2O2
va
H2O2
/UV. Ca hai

phuong phap deu nhanh, cho muc do khoang boa cao va deu co the phan buy ca
cac etylen da clohoa. Nho kha nang loai bo TCE va PCE trong khi xu ly bang O3
ma he
H2O2
/UV dugc
lira
chon cho nhiing nghien
ciiu
tiep xa hon.
Ruppert
[15]
da so sanh
sir
khoang boa 4-clorophenol voi 4 phuong phap
oxi boa cap tien khac nhau co kem theo tia UV. Duoi dieu kien chieu sang bang
den Hg ap suat cao
150
W, su phan buy TOC hieu qua theo thu tu sau:
UV/H202/Fe-^
> UV/O3 > UV/H2O2 =
UV/TiO
Su khoang hoa
UV/Ti02
va UV/H2O2 cho hieu suat kem hon trong viec
tay trang va phan
hiiy
thuoc nhugm.
Oxi hoa cap tien cac hydrocacbon da vong thom (PAHs) va mo hinh boa
toan hgc cua no da dugc Trapido nghien
ciiu

[19]. Nghien
ciiu
nay cho ket luan
hieu suat
ciia
AOPs doi voi
sir
oxi boa antraxen theo thu tu sau:
O3/H2O2
-
O3 > O3/UV > O3/H2O2/UV >
UV
Ket qua tuong tu cho cac PAH khac.
R6
rang o day cac goc OH dong vai
tro
thii
yeu trong viec phan buy antraxen.
Oxi hoa cac nitrophenols voi
O3
va
O3
ket hgp voi
H2O2
va hoac tia UV
cung da dugc Trapido nghien
ciiu
[18,
19].
Tat ca nhung qua trinh nay deu co

kha nang phan buy nitrophenols. Ket hgp O3 voi UV hoac voi
H2O2
thiic day
phan
hiiy
nitrophenols va lam giam tieu thu
O3
ro ret
6
nhirng gia tri pH thap. To
hgp O3/UV va
H2O2
la hieu qua nhat cho phan buy nitrophenols:
03/H202/Uv">
O3 (pH 9,5) >
O3/H2O2
> O3/UV > O3 (pH 2,5)
De dat dugc
sir
tang ve
toe
do phan
ling
va giam cung cap O3, qua trinh
O3/H2O2/UV rut khoat phai dugc
sii
dung o nhirng gia tri pH thap.
Glaze [9] da tong quat boa kinh nghiem
ciia
nhirng nghien

cii'u
khac nhau
de dua ra mot so lugng
Ion
cac chat oxi boa doi hoi ve mat ly thuyet nham thu
dugc mot so lugng cu the cac goc OH (bang 5)
12
"^^
Bang 5. Luang
chat
oxi
hoa ve
mat
ly thuyet va UV doi
hoi
cho
su-
hinh
thanh goc
OH trong cac
he
63/H2O2/I/V.
He
Oa/OH-
O3/UV
O3/H2O2
H2O2/UV
Ty le
moi Oj/'OH
1,5

1,5
1,0
0
Ty le
moi
cua
photon, einstein/ OH
0
0,5
0
0,5
Ty le
moi H202/'OH
0
0,5
(H2O2
in situ)
0,5
0,5
He
O3/H2O2
cho su san sinh goc
*0H
tot, no de thich
ling
voi cac dieu
kien ozon boa hien nay va co gia xu ly tuong doi thap nhat dua tren su oxi boa
goc *OH. Ozon boa
6
pH cao it dugc dung va mac

dii
he O3/UV duong nhu kho
thuc hien tren mot pham vi
Ion,
nhung no co the dugc
diing
thanh cong
6
toe do
dong chay nho hon
Trong 10 nam lai day, mot vai mo hinh AOPs da cho phep nghien
ciiu
tot
hon ve co che qua trinh. Glaze va Kang [9] da mo ta mot mo hinh dong hgc cua
qua trinh
O3/H2O2
dua tren thuc nghiem voi PCE nhu mot hgp chat mau. Mo
hinh dua vao tinh toan lieu lugng O3 va
H2O2,
sir
chuyen khoi O3 va cac phan
ling tieu thu
g6c.
Peyton [7] da gioi thieu mot mo hinh dong hgc cua qua trinh
O3/UV. Mo hinh nay quan tam toi thong lugng
biic
xa, nong do
O3
trong pha
long va he so

toe
do phan
ling
ozon boa.
Mot dong gop hoan toan dang
chii
y den viec mo hinh boa cac AOPs khac
nhau da dugc Beltran [7,
15]
tien hanh. Hg da gioi thieu nhirng mo hinh toan hgc
thii
vi
ciia
O3 va su oxi boa
c4p
tien cac PAH, cac hgp chat nitro thom trong
nuoc va trong nuoc thai. Cac mo hinh toan hgc cua su oxi boa cap tien cac PAH
va clorophenols ciing bao
g6m
cua ca Kallas va Hautaniemi
[12].
Trong cac mo
hinh toan hgc AOPs, 3 PAH (antraxen, phenanthren va pyren)
sir
dung
O3/H2O2,
O3/UV, O3/H2O2/UV va O3 (pH 9,5) da dugc gioi thieu. Mo hinh cac phan ung
hoa hgc da dua vao xem xet
31
con duong phan

ling
co the xay ra. So lugng
lugng
tii
cung nhu
bSng s6 t6c
do phan
ling ciia
phan
tii O3 va
goc
OH
cho
PAHs dugc danh gia tu cac dii lieu thuc nghiem. Ket qua cho thay hang so toe
do phan
ling
trong
xii
ly PAHs bang cac qua trinh AOP co cac gia
trj
tuong doi
thSpgiualO^^-
10^M"'s"'.
Trong cac cong trinh [8,
11]
cac mo hinh toan hgc oxi boa cap tien 3
clorophenol (2-CP, 4-CP va 2,4-CP) trong cac dieu kien axit va bazo cung dugc
xay dung. Duoi cac
di§u
kien bazo (pH 9,5)

sir
ozon hoa CPs xay ra qua nhanh.
Cac phan
ling g6c
hydroxyl khong dong gop vao viec lam tang
toe
do oxi boa
CPs duoi cac dieu kien bazo.
13
^
Trong moi truong axit, co che oxi boa lai khac hoan toan. Nguoi ta da xay
dung mot mo hinh de mo phong viec
xii
ly CPs bang
O3
va O3/UV. Noi chung,
toe
do phan ung CPs khong tang len neu them
biic
xa UV so voi ozon boa mot
minh,
tiic
la
sir
oxi boa
a
cac gia tri pH thap trong ca 2 qua trinh xay ra chu yeu
qua cac phan
ling
voi phan

tii
ozon.
Tom iai, ozon boa va nhiing to hgp cua no voi
H2O2
va/hoac tia UV la cac
phuang phap
xii
ly tuyet voi cho cac
chSt
thai doc hai khac nhau. Cac he thong
O3/UV da dugc lap dat
6
Can
cii
Khong quan Tinker (Oklahoma, USA)
[17]
de
xu ly phuc xianua kim loai va chat hiiu co kho phan
hiiy.
Nam
1978
xu ly bang
O3
da dugc lap dat o Phong (Division) thiet bi dong co 6 to cua Tong cong ty
O
to Cadillac tai Detroit, Michigan (USA). Tii do
miic
CN" tong trong dong chay
da ha xuong < 1 mg/1 va > 99%
O3

dung
6
dang khi da thu dugc on dinh.
Trong nha may san xuat va che bien vi mach, nuoc can rat sach. Zmolek
da xay dung mot he thong
xii
ly nuoc va lap dat o cac phong thi nghiem Bell
Telephone vao nam
1973,
voi to hgp
sii
dung
O3
de kiem soat vi khuan (vi khuan
CO
the bit cac
fil
Igc 0,2
|xm
dan den gay pha hong nghiem trgng cac nguyen to vi
r r
t
r
mach).
Tuong tu, nguoi ta cung lap dat cac he thong diet vi khuan nhu the nay
cho cong nghiep hot giay va giay. Korhonen & Tuhkanen da xac thuc nhiing tien
bg
ciia xii
ly bang O3 va
O3/H2O2

trong viec kiem soat
sir
sinh truong cua vi
khuan trong he thong dich trang cua may giay. Ozon cung dugc
sii
dung (full-
scale) de loai mau nuoc thai cong nghiep det o mot vai nuoc. Tat nhien truoc khi
thiet ke he thong xu ly cho cac nha may cu the, can phai nghien cuu theo quy mo
phong thi nghiem va pilot ve kha nang
ciia O3
de loai mau cac thuoc nhugm cu
thS.
Ozon cung voi GAC [8, 16,
17]
la mot
sir lira
chon tot cho giai phap ve
cac van de moi truong
ciia
cong nghiep dau mo. Cong ty ARCO Products (nay
da dong
cii'a)
xu ly mot trieu gallon nuoc thai dau mo hang nam
6
Richmond,
CA (USA), kho chiia san pham dau va nhiing phuong tien van chuyen de dang
dau mo tu nam
1991.
He thong
xii'

ly nay cung thanh cong va dugc lap dat cho 4
CO
so
O3/GAC
vao nam
1993.
O3,
O3/UV
va O3/H2O2 cung
CO
the giam do doc cap tinh cua dong thai tu
cong nghiep bgt giay va giay [9]. Thanh cong quan trong nhat
ciia O3
la hieu qua
o viec oxi boa pha buy cau triic cua dibenzo-p-dioxin va dibenzofuran-tien than
ciia
cac hgp chat policlorinat. Ozon boa dich trang clohoa cua bgt giay truoc lam
giam
sir
hinh thanh cac hgp chat doc nay dang ke.
Wable
da mo ta nhiing nghien cuu
xii
ly nuoc rac
6
Phap bang
O3
va
O3/H2O2.
Theo cong ty voi nhiing quy dinh moi

ciia
Phap, nuoc rac phai dugc xu
ly truoc khi thai ra moi truong. Leitzke da thao luan
ling
dung oxi boa boa hgc
bang to hgp O3/UV cho nuoc rac cua
Due
truoc khi xu ly sinh hoc. Oxi hoa boa
hoc dugc
sir
dung de lam giam
mii'c
cac chat 6 nhiem bay hoi nhu cac
14
w.
hydrocacbon, cac hydrocacbon da clohoa, cac hgp chat sulfua
6 15-20
cac nha
may
xii
ly dia phuong
6 Diic
va Ao.
Ky thuat oxi boa kem theo chieu
biic
xa cue
tim
( O3/H2O2/UV) dugc ung
dung thanh cong cho viec loai cac chat ban
hiju

co bay hoi (benzen, axeton,
dicloetan,
tetrac'loetan ) tir
nuoc
ngkm
o San Jose, CA (USA)
[15].
Nhi^u
hon
90%
hieu qua cua viec loai bo la cac VOC. Trong thoi gian nam
1994,
mot he
thong UV/oxi boa dugc lap dat o nha may dan dugc
qu6c
phong Milan (Milan,
TN,
USA) de
xii
ly nuoc cac ao
tii
da nhiem ban boi cac
cbSt
no (2,4,6-
trinitrotoluen; 2,4- va
2,6-dinitrotoluen;
nitrobenzen ). Sau buoc oxi boa UV/0
, nguoi ta co the
xii
ly tiep nuoc thai bang each

Igc
qua than boat tinh (GAC).
Nam 1994, mot he thong
xii
ly UV/O3/H2O2 da dugc
lap
dat o co quan (point)
Bofors Nobel Superfund, dong gan Muskegon, MI (USA) de phan buy nuoc thai
doc hai chiia benzen, toluen, clobenzen, tetracloetan, benzidin
Nhu vay, neu dugc
sii
dung mot each
diing
dan, cac AOPs noi chung, se
cho kha nang oxi boa cao hon mot minh ozon. Tuy nhien chiing can dugc danh
gia hieu qua, gia ca va
miic
do oxi boa. Nen
chii
y rang AOPs khong phai la rat
hieu qua de
xii
ly dong thai that dam dac voi nong do chat 6 nhiem hiiu co vai
tram den 1000 mg/1. Tu quan diem hoa hgc
ciia
tong quan, hieu qua cua O3/UV
>
t t t
la ngang
bang

voi he
O3/H2O2
neu
sir
phan quang
true
tiep khong dang ke. Khi
so sanh cac he
OVUV
va
H2O2/UV,
su sinh ra
*0H
theo phuong trinh ty lugng la
Ion
nhat tu qua trinh phan quang
H2O2,
nhung phan quang
O3
thuc te lai sinh
OH nhieu hon boi vi he so tat phan
tii ciia
O3 cao hon so voi
H2O2.
Tuy nhien, phai
chii
y so sanh nay chi la ly thuyet. Trong thuc te,
sir
san
sinh OH

Ion
co the dan
dtw toe
do phan
ling
thap hon vi cac goc tai to hgp lai
% til
deu dan va khong tien ich cho qua trinh oxi boa. Boi the de co mot hieu suat
AOPs mong uoc cho mot hgp chat cu the, viec
lira
ebon he thong AOP cuoi ciing
can dugc lam sau khi c6 khao sat so bg trong phong thi nghiem. Viec so sanh
chung hieu qua xu ly
ciia
cac hgp chat
hiJu
co hoac v6 co khac nhau trong nuoc
la khong can thiet.
De loai
miii,
vi va khu
triing
nuoc uong chi mot minh
O3
la
dii.
Trong
truong hgp co mot vai chat 6 nhiem vi lugng trong nuoc (TTS, huu co
clorinat ) thi to hgp
O3/H2O2,

tiep sau do la he O3/UV la hieu qua nhat va ky
thuat khong dat cho nha may
xii
ly nuoc uong. Mot tien bg
ciia
qua trinh
O3/H2O2
la khong doi hoi bao duong den UV (ve sinh va thay the den); hon
niia
nang lugng yeu cau luon thap hon. Cac nha may
xu*
ly da
sir
dung
O3
nhu mot
buoc
xii
ly co the
dl
dang them
H2O2
de lam tang
toe
do phan
irng.
Oxi hoa quang
xiic
tac trong
xii

ly nuoc da chiing to hieu qua
ciia
no trong
nhieu
ling
dung thuc te.
15
4. Nghien
citu
loai bo cac hap
ch&t
ca clo
bdng
tac nhan phan irng
Fenton
4.1.
Xay dung thiet hi vd cac dieu kien nghien cuu
Do dugc su dung rat rgng rai va co hieu qua, nen cac qua trinh Fenton lien
tuc dugc nghien
ciiu,
cai tien va hoan thien them. Cac tai lieu tham khao cong bo
cho den nay da dua ra cac ket qua nghien
ciiu
lien quan den anh huong
ciia
mot
loat cac nhan to nhu nong do va
miic
do oxi boa cua cac ion sat
(II

hoac III),
nong do
H2O2,
pH, thoi gian phan
ling
va nhiet do phan
ling.
Gia tri pH toi uu dugc neu ra hau bet la
6
xung quanh 3 (Goi, 2002;
Neyens,
2003;
Lopez et
al,
2004). 0 gia tri pH qua cao, Fe(III) se ket
tiia
o dang
Fe(0H)3 va
H2O2
se tu phan huy thanh oxi va nuoc. Thoi gian phan
ling ciia
qua
trinh Fenton la ngan nhat so voi cac qua trinh AOP khac. De phan buy cac
phenol don gian chi can 30 - 60
phiit,
doi voi cac chat hiiu co
phiic
tap hon hay
nong do cao hon thi thoi gian phan
hiiy

ciing chi tinh bang gio
(Hofl
et
al.,
1997;
Martinez et
al.,
2003;
Neyens, 2003). Theo mot so nguon thong tin khac cho
r
r r
thay tang nhiet do phan
ling
se c6 anh huong tot den dong hgc
ciia
phan
ling
va
khoi lugng chat dugc phan
hiiy
(Lopez et al., 2004).
Boi vi phan ung Fenton dugc coi la giai phap huu hieu cho qua trinh phan
hiiy
cac hgp chat hiiu co chiia halogen trong nuoc thai, cho nen trong nghien
ciiu
nay chiing toi da chgn
4-clophenol
(4-CP) la chat dai dien cho cac thu nghiem
cua minh.
Qua trinh phan buy dugc theo doi thong qua chi thi la COD va nong do

chat hiiu co de hap thu lien ket voi cac halogen (AOX) hoac xac dinh do
due
de
tinh toan ham lugng clo tu do. Viec xac dinh cac thong so tren dugc tien hanh
theo tieu chuan tuong ling
ciia
Cong hoa Sec (CSN EN 1485, TNV 75 7520) va
theo Standard methods for environmental wastewater.
Cac
thii
nghiem dugc trien khai trong cac binh non dung tich 250 ml dat
tren may khuay tu.
FeS04.7H20
da boa tan dugc dua vao dung dich 4-clophenol
va tiep theo them dung dich
H2O2
30%. Hydropeoxit dugc cho vao sao cho luon
luon bao dam du gap 10
Ian
khoi lugng can thiet tinh theo ly thuyet de phan
hiiy
hoan toan 4-clophenol. Phan ling dugc tien hanh o nhiet do phong
25''C.
Trong anh huong cua thoi gian phan
ling
den hieu suat loai bo chat
biJu
CO,
n6ng
do ban

d4u ciia
4-CP la 320 mg/L va
ciia
Fe""
la 20 mg/L. Dung dich
trong binh non dugc khuay manh va
cii
sau thoi gian la 0,
15,
30, 60 va 120 phiit
mau dugc lay ra de phan tich COD.
Trong anh huong
ciia
ty le chat
xiic
tac
Fe"^
va
H2O2
den hieu suat loai bo
AOX va COD, mot day thi nghiem dugc tien hanh voi cac nong do
Fe~*
khac
nhau. Cac dieu kien thi nghiem khac giong nhu truong hgp dau. Bao gio cung
sau 30 phiit khuay manh thi \iy mau va xac dinh nong do AOX va gia tri COD
trong do.
4.2. Ket qua nghien cuu vd thao luan
4.2.1.
Anh huong cua thoi gian phan
ling

Ket qua
thii
nghiem mo ta tren hinh 1 cho thay tri so COD dat den gia tri
khong doi sau 30 phiit. Ket qua nay la hoan toan phu hgp voi cac thong so dua ra
ciia
cac tai lieu da cong bo va gop phan khang dinh ve
toe
do chung cua phan
ling Fenton (Lipczynska-Kochany et al, 1995; Hofl et al, 1997).
D6ng
thoi thoi
gian phan
ling
30 phiit nay ciing se dugc chgn
sir
dung nhu la thoi gian ket thiic
phan ling cho cac day thu nghiem tiep theo.
Hinh
4.
L
Hieu suat xir
ly COD
theo
th&i
gian phan irng
4.2.2.
Anh huong cua ty le
moi Fe"V Hn02
den kha nang loai bo AOX va
COD

Ket qua tren hinh 2 chiing to hieu qua
ciia
qua trinh phan buy phu thuoc
kha ro vao ty le nong do cua cac thanh phan
xiic
tac sat(II) va nguon san sinh ra
cac goc hydroxyl -
H2O2.
Trong qua trinh
thii
nghiem, ty le
moi ciia Fe"7H202
dugc thay doi tu
1:
120 den
1:1640.
Ket qua nghien cuu thay rang khi nong do sat(II) giam thi hieu
qua
xii
ly AOX cung nhu COD deu tang va hieu qua cao nhat khi
sir
dung ty le
1:810,
1:980
va
1:1230.
Khi nong do sat(II) tiep tuc giam thi hieu qua
xir
ly ciing
giam.

OAi MUC OuOC
Gi^
^^
NO'
17
v'y/.l^i