Nghiên cứu khả năng hấp phụ chì trong nước rỉ rác của mụn dừa biến tính

TRUONG DAI HQC AN GIANG
. KHOA KY THUAT - CONG NGHE - MOI TRlTCXNG

NGUYEN MINH TRI

NGHIEN ClTU KHA NANG HAP PHU CHI
TRONG NlT6c RIRAC CUA M^N DlTA BIEN TINH
TRUCJNG D/^I HQC
AN GIANG

THUVIEN
KHOA LUAN TOT NGHEEP

GVPB

GVHD

TS. Nguyen Trung Thanh

Ths. Bui Thi Mai Phung

Ths. Phan Triromg Khanh

An Giang, 05/2013


LOtt CAM ON

Em xin chan tbanh cam cm Ban Giam hieu Traang Dai hpc An Giang, Ban
CM nhi^m Khoa Ky thuat - Cong nghe - Moi trudng, Ban Quan ly Khu Thi
nghiem Th\rc hanh Truong Dai hpc An Giang cH tao dieu kien cho em Man

thanh khoa luan tot nghiep nay.
Em xin chan thanh cam on co Bui Thi Mai Phyng da nhipt tinh hudng dan
em trong suot thai gian thuc hien khoa luan.
Em xin cam an thay Nguyen Trung Thanh, co Nguyen Hong Nh^t va anh
Nguyen Van Tuan da ho trp em trong thdi gian em tien hanh thi nghiem.
Cam an Y, Giao, Thanh, Dutc, Cam, Binh, cac ban trong lap, cac ban

trong Hanh trinh xanh An Giang da luon if ben dpng vien, ho trp toi trong suot
thai gian qua./

LongXuyen, ngay 17 thing 5 nam 2013

Nguyln Minh Tri


NH^JlN XET CUA GlANG VIEN HtfOOVG DAN

LongXuyen, ngay 17 (hang 5 nam 2013

^"


NHAN XET CUA GIANG VIEN PHAN BIEN

LongXuyen, ngdy 17 thing 5 nam 2013


NHAN XET CUA GIANG VIEN PHAN BIEN

LongXuyen, ngay 17 thdng 5 nam 2013

ABSTRACT

Thesis title is: " Study the lead adsorption of denatured coir pith from the
seepage water" our experiments were done in environmental lab at An Giang

University from January to April 2013.
First, coir pith is washed, dried and soaked in sulfuric acid (98%) in 2
hours, coir pith / acid proportion (lg : 7,4g) . Then, the coir pith is activated at
150C in 6 hours. After the activation, the coir pith was washed in distilled water
and soaked in O,1N sodium bicarbonate solution in 2 hours to remove any
residual acid. Finally, it is cleaned with water and dried at 150C in 6 hours.
Denatured coir pith is used to carry out the adsorption experiments about
lead adsorption of the coir pith in sewage at pH = 5 and Vrr = 50 ml. The results
identified that the best time of adsorption is 60 minutes and the maximum mass
of adsorption is 0,1 g.
The thesis is also conducted experiments to compare the absorption
capacity lead of coir pith material, denatured coir pith and denatured coir pith
after desorption in the same conditions (pH = 5, V^ = 50 ml, m = 0,1 g, t = 60
minutes). The results show that the performance of lead adsorption of coir pith
material is 68,81%, denatured coir pith is 42,88% and denatured coir pith after
desorption is 35,48%.
Although denatured coir pith is created, but the adsorption just gets a
moderate performance because coir pith itself is infected lead. Therefore, which
materials having lead adsorption with a higher adsorption performance should be
chosen to treat the lead in seepage water./


TOM TAT

Dl tai "Nghien ciiu kha nang hip phy chi trong nude ri rac cua myn dira

biln tinh" dupe thyc hipn tai phdng Thi nghiem Moi trudng thupc Khu Thi
nghiem Thuc hanh, Trudng Dai hpc An Giang tvr thang 1 din thang 4 nam 2013.
Myn dira dupe rua sach, phai kho va ngam trong axit sunfuric (98%), ti le
mun dira : axit la (1 g : 7,4 g) trong 2 gicr. Sau do, mun dira dupe hoat hoa d
150C trong 6 gicr. Sau khi hoat hoa, rua bang nude c^t va ngam trong NaOH
O,1N trong 2 gid de trung hoa axit. Sau do, rua sach bang nude, phai kho ngoai

khong khi va sdy d 150C trong 6 gid.
Vat lieu hip phy dupe dung dd tidn hanh cac thi nghiem hip phy chi trong
nude ri rac (d pH = 5, Vn- = 50 ml). K6t qua xac dinh dupe thai gian hip phy tot
nhat la 60 phut, khoi lupng vat lieu hap phy tot nhat la 0,1 g.
DS tai cung tiln hanh thi nghifm so sanh kha nang hip phy chi ciia mun
dira nguyen lieu, vat lipu hip phy va vat lieu hip phy sau giai hip d cung dilu
kien (pH = 5, Vn = 50 ml, m = 0,1 g, t = 60 phut). Kit qu4 cho thly hieu suit hip
phy chi cua mun dira nguyen lieu, vat lieu hap phy va vat lipu hap phy sau giai
hip Ian Iupt la 68,81%, 42,88% va 35,48%.

Mac du da tao dupe vat lipu hip phy nhung hipu suit hip phy chi d muc
tmng binh vi ban than myn dira da bi nhiem chi. Vi vay, nen lya chpn vat lieu
khac cd kha nang hip phy chi vdi hieu suit hap phy cao de xu ly chi trong nude
ri rac./


Khoa Ivan tot nghi?p

MUC LUC

DANHSACHBANGiv

DANHSACHHINHv
DANH MUC TIT VIET TATvi
CHUONG 1: GlCil THIgU1
CHUONG 2: LU0C KHAO TAl LIEU2
2.1Thanh phan va anh hudng cua nude ri rac d^n moi trudmg2
2.1.1Thanh phdn cua nude ri rac d bai rac Binh Due2
2.1.2Anh hudng cua nude ri rac d^n moi trudng ik, nude, khong khi4
2.2Khai niem kim loai nang va dpc tinh cua chi6
2.2.1Khai niem kim loai nang6
2.2.2Kim lord nang chi7
2.2.3Cacngudnphatsinh chi8
2.2.4Dpc tinh ciia chi9
2.2.5Dau hieu nhilm dOc chi9
2.3Mpt so phuong phap xd ly kim lo^ii nang trong nude thai10
2.3.1Phuong phap k^t tua10
2.3.2Phuong phap trao ddi ion10

2.3.3Phuong phap hdp php11
2.4Gidi thieu chung vS phuong phap hip phu11
2.4.1Khai nipm Mp php11
2.4.2Ban chat cua sir hap php11
2.4.3Hap phu trong moi trudng nude12
2.4.4Dong hpc hap phu13
2.5Thanh ph^n, tinh chdt va dng dung cua mun dira13
2.5.1 Tinh chit va thanh phln cua mun dira14
GVHD: Ths. Biii ThiMaiPhung


Khoa luan tdt nghi$p

DHIOMT- Ni

2.5.2 Cong dung cua mun dtra15
2.6Mpt so phuong phap bien tinh vat lieu co nguon goc tp nhien thanh vat lifu

happhu

16

2.6.1Bdi vdi vat lieu la mun dira va ba mia16
2.6.2B6i vdi vat lifu la xo dira, vo trSu va tro trdu16
2.7Cac nghien ciiu \b kha nang hip ph^ kim loai nang cua VLHP co ngudn
g6c t\r nhien17
2.8Ly do chpn phucmg phap18

CHLTONG 3: PHUtiNG TIEN VA PHI/ONG PHAP NGHIEN CLTU20
3.1D6i tupng nghien ciiu:20
3.2Thcri gian va dia diem nghien ciiu20
3.3Mpc tieu nghiSn ciiu20
3.4Npi dung nghien ciiu20
3.5Phucmg tien va vat lieu nghien ciiu21
3.5.1Vat lieu thi nghiem21
3.5.2Phuong tiSn nghien ciiu21
3.5.3Hoa chat phantich21
3.6Phucmg phap nghi^^ ciiu21
3.6.1Phucmg phap thu, c6 dinh va bao quan nuoc ri rac21
3.6.2Phucmg phap hoat hoa mpn dira bang axit H2SO4 dac22
3.6.3Phuong phap vo co hoa mlu mun dira va xac djnh ham lupng chi trong
mun dira22
3.6.4Phuong phap xac dinh chi trong nude ri rac23

3.6.5B6 tri thi nghiem23
3.6.6Phuong phap xur ly s6 lifu27

CHUGNG 4: KET QUA THAO LUAN...28
4.1 Nong dp chi trong mgn dira va nude thai d^u vao28

GVHD: Ths. Bui TMMaiPhung


Khoa lugn tot nghiep

4.1.1N6ng dp chi trong mun dira nguyen lipu va san pham sau hoat hoa blng
axitH2S04dac28
4.1.2N6ng dp chi trong nude rirac.28
4.2Trio vat lieu hap phu bang mpn dira29

4.3Anh huong cua thcri gian hip phu va kh6i lupng VLHP d^n dung lupng hdp
phu chi trong nude ri rac30

4.3.1Anh huong cda thiri gian hSp phu d6n khi nang hip php chi30
4.3.2Anh hudng cda kh6i lupng VLHP d^n kha nang h^p phu chi31
4.4BCha nang hip phu chi cua mpn dira nguyen lifu va VLHP32

4.5Kha nang hip phu chi cua VLHP va VLHP sau giai hip lln 134

CHHC5NG5:KETLUANVAKIENNGH!37
5.1Kltluan,37

5.2 Kiln nghi;37

PHU LUC 1
PHU LUC 2
tAi li$u tham khAo:

GVHD: Ths. Bui Th\ Mai Phung


Khoa lugn tot nghi^p

DANH SACH BANG
Bang 2.1: Thanh phin nude rl rac dien hinh3
Bang 2.2: Ham hrpng kim loai nang trong nude ri rac4
Bang 2.3: Tinh chit va thanh phin cuamun dtra15
Bang 3.1: Thi nghiem xac dinh thai gian hip php cua VLHP d pH = 5, m=0,05 g. 24
Bang 3.2: Thi nghiem xdc dinh khdi lugng VLHP d pH = 5, thai gian t6i uu to

thi nghiem 125
Bang 3.3: Thi nghiem xac dinh khdi luong mpn dira nguyen lieu d pH = 5, thai

gian tii uu to thi nghiem 125
Bang 3.4: Thi nghifm kha nang hip phu chl ciia VLHP sau giai hip d pH = 5,

thdi gian tdi uu d thi nghiem 126
Bang 4.1: Nong dp chi trong mun dtra nguyen li^u va sau hoat hda28

Bang 4.2: Ndng dO va hieu suit chi duac hip php trong VLHP30
Bang 4.3: Nong dp va hieu suit chi hip php trong VLHP sau thdi gian lie 60

phut31
Bang 4.4: Kha nang hap phu chi cua mpn dtra nguyen lieu vdi thdi gian lac la 60

phut33
Bang 4.5: Kha ndng hip phu chi cua VLHP sau giai hip lin 1;34

GVHD: Ths. Bui Thi Mai Phung


Khoa lugn tot nghi^p

DANHSACHHINH
Hinh 2.1: Mun dira tho13
Hinh 3.1: Qud trlnh ho^t hoa mun dira bang axit sunfuric22
Hinh 4.1: Mpn dira nguyen li?u29

Hinh 4.2: Valt lieu hip phu29
Hinh 4.3: Bilu d6 hieu suit hip phu chi cua VLHP theo thM gian31
Hinh 4.4: Bieu d6 hieu suit hip php chi cua VLHP theo kh6i lug^g:32
Hinh 4.5: Bilu d6 kha nang hip phu chi cua nguyen lieu va VLHP34

Hinh 4.6: Bilu d6 khd nang hip php chi cua VLHP va VLHP sau giai hip lln 1 ...35

GVHD: Ths. Bui ThiMaiPhung


Khoa luan tot nghiep

DHIOMT- Nativen Minh Ti

DANH MVC TU" VIET TAT

BOD

Nhu cau oxi sinh hpc

COD

Nhu cau oxi hoa hpc

Ctv

Cong tac vien

EC

Dp dan dien

KPH

Khong phat hipn

NT

Nghiem thiic

DC

D6i chiing

QCVN

Quy chuan Viet Nam

s.

Dien tich rieng b^ mat

VLHP

Vat lieu h^p phu

GVHD: Ths. Bui Thj Mai Phimg


Khoa lugn tot nghiep

CHl/GNG 1
GIOfI THI^U

Ben Tre la mpt tinh nam or ha luu song Mekong, dupe bao hoc bdi b6n
nhdnh cua song Tiln. Hang nam, Bin Tre nhan mpt lupng phu sa ldn ttr sdng, tao
nen nhung cu lao mau mo, thfch hop dl trlng cay nong nghiep. Cay dira dupe
xem la bieu tupng cua Bin Tre. Bin Tre dupe xem la thu phu cua cay dira vdrt
dien tich tren 52.000 ha va san lupng han 410 trieu qua/nam nam 2012.
Cac nganh nghl lien quan din cay dira cung phdt trien manh it B^n Tre nhu
chl biln com dtra nao say, lam thach dtra, chl biln cac san pham thu cong
nghiep tir dira,... Trong do, nghl lam chi xo dira phat triln kha manh trong
nhung nam g^n day, tuy nhien trong qua trinh san xudt cung tao ra mpt lucmg Ion
khoang 180 nghin tan/nam php ph^m la mpn dira - phu pham cua san xudt chi xa
dira. Gid tri ve nong nghi^p cua mun dira khong dang ke. Da so cac ca sd san
xuat chi xa dira thai bo mpn dira xuong song gay 6 nhiem nguon nude va m^t ve

my quan (Kim Ngdn, 2012). Trong nhung nam g^n day da cd nhilu nghien cdu
tan dung mun dtra lam v^t lieu xay dpng, mang lpc trong cong nghiep, san xudt
gia thl dat sach trong nong nghiep...nhung vln khong xur ly hit lupng mun dira
thai ra hang ngay... Do vay, viec nghien cuu tlm ra nhQng ling dung khac cua
mun dira se giiip giai quyet van de 6 nhiem moi trudng.
Hi^n nay, tinh trang 6 nhilm moi trudng do nude ri rac d cac bai rdc 16
thien la rat nghiem trong. Nude ri rdc ngoai ham lucmg chat hilu ca cao con cd
chda nhieu kim loai nang, trong do chi la mot kim loai nang cd dpc tinh cao gay
6 nhiem moi trudng sing cua dpng thuc vat, neu khong dupe xu ly tript dl se gay
anh hudng true tilp, lau dai din moi trudng va sure khde ngudi dan sing gin khu
vuc bai rdc.

HiSn tai, d Viet Nam da cd mpt si nghien cuu vl kha nang xu ly kim loai
nang bang cd vertiver, xa dda, vd trdu, vd dau xanh, ba mia... trong nude thai.

Tuy nhiSn, chua cd nhilu nghien ciiu vl kha nang hip phu kim loai nang cua
mun dira. Chung toi se tiln hanh nghien cdu vl kha nang hip phu chi trong nude
ri rdc cua mun dira sau khi da lam bien tinh.

GVHD: ThS. Bui ThiMaiPhwg


Khoa luan tot nghi^p

DHIOMT-Nguyen Minh

CHI/ONG2
LUQfC KHAO TAI LIEU

2.1 Thanh phan va anh hirong cua nude ri rac den moi triremg

Nude ri rdc la nude ban tham qua cdc ldp rac cua cac 6 chon lap, keo theo
cac chat 6 nhiem d dang hoa tan hoac la lurng tvr rac chay vao tang dat a dudi bai
chon lap. Nude ri rac du^e hinh thanh khi dp am cua nude rdc vupt qua dp giu:
nude (dp gift nude cua chat thdi rdn la lupng nude ldn nMt dupe giti: lai trong cac
16 rong ma khong sinh ra dong thlm, hudng xu6ng dudi tac dung cua trpng lpc)

(PhgmHdngNhat, 2001).
2.1.1 Thanh phan cua nude ri rac d bai rac Binh Sue
Nhln chung, nude ri rac mdi chiia ham lupng chit httu ca cao, chura nhi^u
chat hda tan vd kim lopi npng nhu Zn, Ni, Cr, Cu, Pb, Hg... cung nhu mot s6
chit doe khac.
Ngoai ra, nhung bai rac chura chat thai cong nghiSp thl nude ri rac cua
chung chura ede chat vo ca va kim loai nang kha cao, con nude ri rac sinh ra tvr
cac bai chon ldp sinh hoat thi chura chit 6 nhilm sinh hpc va ham lupng vi sinh
cao (Le Minh Thanh, 2007).
Nude ri rdc sinh ra tvr cac bai chon lap chdt thai tra (gach ngdi, da, xa
ban...) thi mure dp nguy hpi cua nude ri rdc thap han so vdi nude ri rdc tir ede bai
chon lip chit thai rin sinh hoat va c6ng nghiep (Nguyen Van Phu&c, 2011).

GVHD: ThS. Bui ThfMaiPhmg


Khoa iugn tot nghiep

DH10MT- Native/1 Mink

Bang 2.1: Thanh phdn nude ri rdc dien hinh

Gia tr j (mg/1)
Thanh phan

Don vi

Baimoi
Khoang

Bai trcn 10
nam

Trung binh

BOD5

mgO2/l

2.000 - 30.000

10.000

100-200

TOC

mg/1

1.500-20.000

6.000

80,0 - 160

COD

mgO2/l

3.000-60.000

18.000

100 - 500

TSS

mg/1

200 - 2000

500

100 - 400

Nitrogen hftu cor

mg/1

10 - 800

200

80,0 - 120

Ammonia

mg/1

10 - 800

200

20,0-40,0

NO3"

mg/1

5-40

25

5,00-10,0

T6ngP

mg/1

5-100

30

5,00-10,0

Dp kiSm theo CaCO3

mg/1

1.000 - 10.000

3.000

200 -1.000

pH

-

4,5 - 7,5

6,00

6,60-7,50

Ca

mg/1

200-3.000

1.000

Mg

mg/1

50-1.500

250

50,0 - 200

K

mg/1

200-1.000

300

50,0 - 400

Na

mg/1

200-2.500

500

100-200

cr

mg/1

200 - 3.000

500

100 - 400

so4"

mg/1

50-1.000

300

20,0 - 50,0

T6ng sit

mg/1

50-1.200

60,0

20,0 - 200

.

100-400

(Nguon: Tchobanoglous et al, 1993 trich hoi Dinh Xudn Thdng vet Nguyen

Dinh Tudn, 2010)

GVHD: ThS. Bui ThiMaiPhung


Khoa luQtn tot nghiep

Bang 2.2: Ham lupng kim loai nang trong nude ri rdc(Dan vi: mg/l)
Binh Due-Long XuyenChau Doe cuQCVN

STT T"Tg~
S0

2009

2010

2011

2009

2010

24:2009
2011

1CuKPHKPH0,058KPHKPH0,1022,00
2Pb0,0300,0040,0070,00350,0220,0090,50
3Zn0,6500,7600,0650,4100,4500,2073,00
4As0,0160,0150,0070,0180,0010,0110,10

5HgKPHKPH0,009KPHKPH0,0160,01
6CdKPHKPH0,005KPHKPH0,0020,01
(Nguon: Trung tarn Quan trac vd Ky thuat Tdi nguyen - Moi truang An Giang,

2012)

Dua vao bang 2.2 ta thay ham lucmg kim loai nang trong nude ri rac d bai rac

Binh Bute d6u thap hem QCVN 24:2009.
Trong nude ri rac cd sir hien dien ciia chi vdi nong do thap so vdi QCVN 24
: 2009 do mpt so nguyen nhan nhu: moi n5m chi tien hanh quan trac mpt Ian vao
thdi dilm la thang 9 - dung vao thdi dilm miia mua d Nam Bp va cd th6 ndi
thang nay mua r^t nhiSu. Do do, ndng dp cua chi trong nude ri rac bi pha loang.
Bong thdi, chi cung cd kha nang bi Iang xuong biin day va tham vao trong dat
nen ham lupng chi trong nude ri rac thap. Vi the, nong dp chi thuc su trong nude
ri rac cd the ldn hern rat nhieu.
2.1.2 Anh liudng ciia nude ri rac den moi trudng dat, nude, khong khi
Su cd mat ciia nude trong bai chon lap rac pd ca mat tich cue Ian mat tieu
cue cho hoat dpng cua bai rac. Nude rat can cho mot sd qua trinh hda hpc va sinh
hoc xay ra trong bai chon lap dl phan huy rac. Mat khac, nude cd thS tao ra xdi
mdn tren tdng d^t nen vh nhumg v^n Ah lfing dpng trong ddng nude mat chay qua.
Nude ri rac cd the chay vao cac tang nude ngam va cac ddng nude s^ch va tu do
gay 6 nhiem den nguon nude uong (Nguyen Van Phudc, 2011).

GVHD: ThS. Bui Thf Mai Phung


Khoa ludn tdt nghiep

Nude ri rac la mpt loai nude thai co kha nang gay 6 nhiem nang ne, chda
cac chat 6 nhiem rat cao va tac dpng ldn den moi trudng dat va moi trudng nude
va siic khde con ngudi.

a)Tac dpng len moi trudng dat
Qua trinh luu gift nude trong dit va ngim qua cac ldp dit be mat ciia nude
ri rac lam cho svr tang trudng va qua trinh hopt dpng cua vi khuin trong dit kem
di, lam giam qua trinh phan huy cac chit hftu co thanh cac chit dinh dudng cho
cay trdng, true tilp lam giam nang suit canh tac va gian tiip lam cho dit bi thoai
hda bac mau.

Anh hudng cua nude ri rac din dit dai se nghiem trpng, mang tinh lau dai
va rat khd khic phuc neu no dupe thim theo mach ngang. Chinh vi vay di han
che va ngan ngira kha nang 6 nhiem dat, ngudi ta ap dpng cac bien phap an toan
trong cong tac chon lap rac, chu yeu bang each xay dung cac de chan bang
betong de ngan chan kha nang tham theo chieu ngang cua nude rd ri, dong thai
phai lap dat he thing thu gom va xd li nude ri rac (Dinh Xudn Thdng vd Nguyen
Dinh Tudn, 2010).
b)Tac dpng len moi trudng nude
Nude ri rac cd chua nhiiu chit hda tan va co thi co ca cac vi khuin gay
bpnh di chuyin tham nhap vao nguin nude ngim, kit qua la nguin nude ngim bi
6 nhiem npng. Su 6 nhiem cung cd the xay ra tuang tp doi vdi cac nguon nude
mpt.

Cac kim loai nang la mpt chi tieu rit quan trpng trong kiim soat nude ngim

khu vuc bai chon lip. Do khong bi vi sinh vat phan huy va di bi hda tan vao
nude trong moi trudng axit nen kha nang xam nh^p cua kim lopi nang vupt qua
ngudng cho phep. Kim loai nang khong chi gay 6 nhiem nude ngam ma con cd
kha nang 6 nhiem cho nguon nude mat khi cac chat 6 nhiem theo nude ngam hda
va cac con song, suii, ho.. .gay 6 nhilm cho nhung thiiy vpc rit xa nai phat sinh
6 nhilm. (3 ndng d^ cin thiit, cac kim lopi nang la nguyen ti thiit yiu cho sp
phat triin ca thi, nhung d ndng dp cao se gay dpc cho ngudi va smh vat (Nguyin
Trdn Thi?n Khdnh, 2006).
c)Tac dpng len moi trudng khong khi
Trong qua trinh phan huy ky khi chat thai ran tao nude ri rac thi cung san
sinh khi thai la CH4 va CO2 chilm ty phin the tich cao nhit, khi H2S,
metylmercaptan (CH3SH) va NH3 chilm ty phin thap nhung lai la nguyen nhan
gay 6 nhilm miii.
GVHD: ThS. Bui ThfMaiPhiing


Khoa loan tot nghi^p

Ndu khi CH4 tdn tax trong khdng khi d ndng dp tu 5 - 15% se phat n6, do
ham lupng oxygen tdn tai ben trong bai rac ft ndn khi ndng dp khi CH4 dat ddn
ngudng vin it kha nang gay n6 bai ch6n l^p. Tuy nhidn, ndu cac khi trong bai
chon lap thoat ra ben ngoai va tidp xiic vdi khdng khi, co kha nang hinh thanh
hdn hpp khi CH4 d gidi han gay nd. Cac khi nay cung tdn tai trong nude ri rac
vdi n6ng dp tuy thudc vao ndng dp cua chiing trong pha khi khi tidp xiic vdi nude
ri rac. Ngoai ra, khi CH4 va CO2 dupe sinh ra nhieu se gay 6 nhiem mdi trudng,
lam gia tang hidu ling nha kinh va lam ngat thd ddi vdi ngudi, ddng vat d bai
chon lap va khu vuc xung quanh (Nguyen Van Phu&c, 2011).
2.2 Khai niem kim loai nang va dpc tfnh cua chi
2.2.1 Khai niem kim loai nang
Co 2 dinh nghia \b kim loai nang dira tren hai quan di&n nhu sau:

Theo quan di^m ve ti trong, dinh nghia kim loai n^ing la cac kim loai cd ti
trpng (ky hieu d) ldn hem 5, nghia la chung nang glp 5 lln hoac han ntta so vdi
khdi hrgrng rieng ciia nude, bao gdm: Pb (d = 11,34), Cd (d =^ 8,6), Fe (d = 7,87),
As (d = 5,72), Zn (d = 7,10), Co (d = 8,9), Cu (d = 8,96), Mn (d = 7,44)...
(Prasad, 1974 trich trong Phan Th\ ThuHSng, 2008).
Theo quan di^m dpc hoc, dinh nghla kim loai nang la cac kim loai cd nguy
ca gay nen cac vln Ah \h moi trudng, bao gdm: Cu, Zn, Pb, Cd, Hg, Ni, Cr, Co,
Vn, Ti, Fe, Mn, Ag, Sn, As, Se. Bdn nguyen td dupe quan tarn la Pb, As, Cd va
Hg. Cac nguyen td nay hien nay chua biet dupe vai trd sinh thai cua chung, tuy
nhien neu du mpt lupng nhd 4 nguyen td nay thi tac hpi rlt ldn (Phan Th\ Thu
H&ng, 2005).
Trong tu nhien, kim loai nang ton ttrudng dat, mdi trudng nude.
Trong mdi trudng khi, kim loai nang ton tai d^mg hai kim loai.
Trong mdi trudng dat, kim loai nang tdn tai d dudi d^ng kim loai nguyen
chit, cac khoang kim loai hoac cac ion. Kim loai n^ng cd trong dlt dudi dang ion
thudng dupe thuc vat hip thu lam cho thpc vat bi nhilm kim loai nang, theo
chudi thurc an vao ca thd ngudi.
Trong mdi trudng nude, kim loai nang tdn t^i dang ion hoac phuc chit...
Trong ba mdi trudng thi mdi trudng nude la mdi trudng cd kha nang phat tan
kim loai nang di xa nhat va rpng nhat. Trong nhtlng dieu kien thich hpp kim loai
nang trong mdi trudng nude cd thd phat tan vao mdi trudng dat va khi. Cay trdng
bi nhidm kim loai nang khi dupe tudi blng ngudn nude cd chuta kim loai n^ng

GVHD: ThS. Bid ThiMaiPhung


Khoa hidn tot nghi^p

hoac dSt Pdng cdy bi 6 nhilm bdi ngu^n nude co chua kim lopi nang di qua no.

Do do, kim loai nang trong mdi trudng nude cd the di vao ca the con ngudi
thong qua con dudng an udng (Nguyin Van Phxtdc, 2010).
2.2.2 Kim loai nang chi
Vi tri, cdu tao cua chi trong bang tudn hoan cac nguyen t6 hda hoc: Chi cd
s6 thd tu 82 trong bang tudn hoan, ki hieu la Pb, khdi lupng nguyen tu la 207,2
dvc, dd am dien la 2,23, thd dien e^e chuan -0,126 V, chi cd 2 s6 oxi hda la +2 va
+4.

Tinh chat vat ly: Chi la kim lo^i mau xam tham, kha mem, de dat mdng,
nhi^t do ndng chay 327,46C, nhiet dp sdi 174C, khdi lupng rieng 11,34 g/cm3.
Chi va hop kim cua chi rat dpc do cd kh^ nang tich luy trong cac bp phan cua
dpng thuc vpt. Chi hap phu tdt cac tia phdng xa.

Tinh chdt hda hoc
??? Tac dpng vdi oxi
Chi bi oxi hda d dieu kien thudng tao thanh mang oxit bao ve cho kim lo^i.
Khi dun ndng trong khdng khi, chi bi oxi hda dan ddn hdt tao ra PbO
2Pb + O2 = 2PbO
?Tac dpng vdi cac phi kim khac
Chi tac dpng vdi cac halogen, luu huynh tao thanh mudi

Pb + S=PbS
Pb + Cl2 = PbCl2
?Tdc dung vdi nude
Chi khdng tac dung vdi nude d nhiet dp thudng. Nhung d nhiet dp cao chi
phdn ung chdm vdi nude khi cd mat cua oxi tao ra hidroxit:

2Pb + O2 + 2H2O = 2Pb(OH)2
?Tac dung vdi axit
Chi tac dung vdi axit khdng cd tinh oxi hda nhu HC1, H2SO4 loang...giai

phdng khi hidro

GVHD: ThS. Bui ThiMaiPhung


Khoa lugn tot nghi?p
Tuy nhien, khi chi tan trong HC1 tao ra ldp PbCl2 khd tan lam cho chi
khdng tan them dupe nua, nhirng vdi HC1 dye chi lai de tan hon do tao thanh horp

chat dl tan dang H2[PbCl4]
PbCl2 + 2HC1 = H2[PbCl4]
Vdi cac axit co tinh oxi hoa nhu HNO3, H2SO4 dac thi chi hoat dong manh
Pb + 2H2SO4 dac = PbSO4 + SO2 + 2H2O
Chi chi tac dung tren be mat vert dung dich H2SO4 co ndng dp thip hou
80% tao ra ldp mu6i kho tan.
Nhirng vdrt axit HNO3, chi tac dung a bit ky ndng dp nao ddu tao ta
Pb(NO3)2. Tuy nhidn do Pb(NO3)2 kho tan frong HNO3 dac, de tan trong nude
nen chi de tan trong HNO3 loang, kho tan trong HNO3 dac.

3Pb + 8HNO3 = 3Pb(NO3)2 + 2NO + 4H2O
Chi cung tan trong axit axetic va mot s6 axit hum ca khac khi co mat oxi.

2Pb + 4CH3COOH +O2 = 2Pb(CH3COO)2 + 2H2O
Dac biet, chi con co the tan trong dung dich ki&n dac nong

Pb + 2KOH + H2O = K2[Pb(OH)4] + H2
(Ngudn: Luang Thi Loan, 2009).
Chi trong m6i trucmg: Muoi chi hoa tri 2 xuit hien nhi^u nhit trong moi
trudng tu nhien va co dp ben cao nhat, chi ton t^i trong cac quang galenit (PbS),

Cesurit (PbCO3), Anglesit (PbSO4). Trong nude dp tan la tinh nang duy nhit xac
dinh hprp chat cua chi, dd tan cua chi phu thupc vao pH, khi pH tang thi dd tan
giam, ngoai ra con phu thupc vao dp mudi cda nude va didu kien oxi hoa khu...
Trong khi quyen, chi tumig ddi giau hem so vdi cac kim loai khac (Le Xuan Thu,

2009)
2.2.3 Cac nguon phat sinh chi
Ham lupng chi trong vd Trai dit la 10 - 20 mg/kg. Cdc hoat dpng nhu khai
thac quang chda chi, tinh luyen chi, thep, su dung pin, acquy cd sir dyng didn eye
chi, su dyng xang pha chi trong cac phuong tien giao thong, san xuit cac loai
som, thudc trtr sau cd sd dung chi lam gia tang lupng chi trong mdi trudng...

GVHD: ThS. Bui ThfMaiPhung


Khoa lugn tdt nghiep
2.2.4Bpc tinh cua chi
Chi la kim loai co dpc tinh cao, gay 6 nhiera moi trucmg song cua dng thyc
vat. Chi co the tich ty trong cay trong trong qua trinh sinh trudng cua cay, do do
d6i vdi cay luong thyc bi nhilm chi, nguoi sil dung chiing co thi bi ngp dOc chi.

Chi di vao co thi thong qua cac dudng ho hip (hit ph&i bui, khong khi,
khdi, hoi co chiia chi), qua dudng tieu hoa (an, u&ng thiic an co chi, che dp an
thilu chat dinh duong dac bipt la cac ion sit, kem, canxi), qua da (do tilp xiic lau
dai vdi cac vat dung nhilm chi).
Sau khi duyc hap thu vao co the, chi vao mau ya it nhit 99% lugng chi g^n
vao hong cau. Sau do di vao cac mo va xuong (dac biet la vo xuong co thl tich
luy ttr 70 - 95% luong chi). Co the cung co co chi dao thai chi thong qua nude

tieu (khoang 65%), qua mat (khoang 35%) nhung tic do tich tu Ion gdp nhilu lln

so vdi tic dp dao thai.
Chi co trong hp thin kinh trung uong dac bipt nguy hilm gay tin thuong,
gay chet tl bao thin kinh, huy hoai day thin kinh trung uong. Chi gay thilu mau,
gay tin thuong than, tang huyet ap, giam chiic nang sinh san, thai nhi bi di dang,
trd bi thilu nang tri tup...().
2.2.5Dan hieu nhilm dpc chi
a) d tre em
ThSn kinh: hon me, co giat, co the tang kich thich, ngu lim tung luc, lipt,
thai dp hanh vi ky di, it choi, met moi, khd chiu, vo cam, mat phoi hop, mat di
cac ky nang hpc dupe, hoc kem, cham phat triln tinh than. Khi tre co bilu hien
nang tren thin kinh trung uong (hon me, co giat) thi 25 - 30% si tre nay co di
chdng (cham phat triln tri tup, co giat, mu, lipt) vlnh viln.
Tieu hoa: Non, dau bung, chan an

Mau: thilu mau
Tre cham phat triln, giam kha nang nghe, cham phat triln vl thin kinh
nhan thiic, cac hanh vi hung hang, chiing tang van dpng va giam tap trung
Cac nghien ciiu cho thay co moi lien quan ty lp nghich giiia chi so IQ cua
tre em va nong dp chi mau, kl ca khi nlng dp chi mau dudi 10 mcg/dL
(http://www. Chongdoc. org. vn).

GVHD: ThS. Bui Thi Mai Phung


Khoa luan tdt nghiep

b) 6 ngirbi ldn
Than kinh trung uong: la ma, Ian lpn, sang, de budn ngu, mat ngu, h6n me,

co giat, dau dau, mat trf nhd, liet

Tieu hoa: mieng co vi kim loai, chan an, tao bdn, can dau bung
Ca, xuang, khdp: dau ca, yiu ca, dau khdp
Mau: thiiu mau, ngufri ta da thfiy dpc tinh cua chi vdi mau ngay ca khi chi

mau dudi lOmcg/dL
Sinh san: giam tinh due, giam kha nang sinh de, dl xay thai, de non, cham
phat triln thai, di dang thai,...
Than: Bfnh than
Ngp d6c man tinh bilu hien d nhi^u ca quan miic dp tuong quan vdi n6ng
dp chi mau. Dc biet chi mau co tuang quan vdi mute dp tang huy6t ap, miic dp
cac roi loan cua lao hoa, bao g6m suy giam tri tue, roi loan chdc nang thSn man
tinh va due thuy tinh thl ().
2.3 Mpt so phuong phap xv ly kim loai nang trong nude thai
2.3.1 Phuong phap kit tua
Nguyen tac chung cua phuang phap kit tua la them mot tac nhan tao kit
tua vao dung dich nude, diiu chinh pH cua moi trudng di chuyin ion cin tach vi
dang hpp chat it tan, tach ra khdi dung dich dudi dang ket tua
Xudt phat tur phuang trinh sau:
M1^ + nOH"^M(OH)nl
Trong do n la hoa tri cua cac cation kim loai (n = 2, 3)
Vdi qua trinh ket tua cua hydroxit kim loai nang pH cua dung djch nude
anh hudng rit manh (Phung Th\ Kim Thanh, 2009).
2.3.2 Phuong phap trao ddi ion
Day la phuang phap kha pho bien su dpng cac chat cd kha nang trao doi ion
(ionit hay con gpi la nhira trao ddi ion) vdi cac cation kim loai nang de giu, tach
cac kim loai ra khdi nude (Phiing Thj Kim Thanh, 2009).
nRH + M"+ ^ R^M + nlT
RC1 + A"

GVHD: ThS. Bui Th\ Mai Phiing

Khoa lugn tdt nghi^p
2.3.3 Phiromg phiSp hap phu
Phvtcmg phap nay sft dung cac vat lieu hap phu (VLHP) co dien tich be mat
rieng ldm, tren do co cac trung tarn hoat dpng, co kha nang luu gift cac ion kim
loai nang tren be mSt VLHP. Vifc luu gift cac ion kim loai nang co the do lire
tuomg tac gifta cac phan tft (lire VandeVan - hap phu vat ly), cung co the tao
thanh cac lien ket hoa hoc, tao phftc chat gifta ede ion kim loai vdi cac nhom
chftc (trung tarn hoat dong) co tren bi mat VLHP (hip phu hoa hoc), cung co thi
theo co chi trao d6i ion... (Phiing Thi Kim Thanh, 2009).
2.4 Gifti thieu chung ve phirong phap hap phu
2.4.1Khai niem hap phu
Hap phu la qua trinh lien kit khi hoac chat long tren bi mat vat thi rin xip.
Chat co be mat tren do xay ra sir hip php dupe gpi la chit hip phu, con chit dupe
tich luy tren be mat chat hap phu gpi la chat bi hap php. Qua trinh hap phu co the
la qua trinh chpn Ipc va thu^n nghich, co nghTa la moi chat hap phu chi co kha
nang hap phu nhftng chat xac dinh va khong hap phu nhftng chat khac co trong

hon hpp khi hoac dung dich. Cac chat bi hip phu cd thi tach ra khoi chat hip php
b3ng each giai hip (Phgm Nguyen Chucmg va ctv, 2002).
2.4.2Ban chat cua su hap phu

Cac phin tu tr^n hi mat chit hip phu luon tin t^i mpt nang lupng du do
gioi h^n be mat cua VLHP va su mat trat tu ben trong cau true cua VLHP.
Chinh nguin nang lupng du nay da giup cac phan tu: co kha nang bit liy
cac phan tft khac nim gin vi tri do tren bi mat VLHP di giai phong nguin nang
lupng du. Day chinh la ban chat cua hien tupng hap phu va vi tri co nguon nang
lupng nay gpi la tam hap phu (trung tam hoat dpng).
Khong thi xac dinh gia tri nang lupng du nay. Tren thuc te ta chi co thi

danh gia kha nang hap phu cfta VLHP thong qua thong so dien tich be m^t cfta
mpt gam chat hap phu, ki hieu Sr, don vi m2/g). VLHP-co be mat rieng cang ldm
thi kha nang hap phu cang ldm. Ngoai dien tich be mat thi ban chat cfta chSt hap
phu va yeu ti hinh hpc cung gift vai tro quyit dinh den qua trinh hip php.
Tuy theo ban chat cfta luc tuomg tac ma nguoi ta chia thanh hai loai hap phu

la hip phu vat ly va hip phu hoa hpc (Le Ngoc Hang, 2009)
a. Hap phu vat ly

Cac phan tft chat bi hip phu lien kit vdi nhftng tieu phan (nguyen tft, phan
tft, ion..'.) ft be mat phan chia pha bfti Ipc lien kit VandeVan. Do la ting hpp cua

GVHD: ThS. Biii ThiMaiPhvng


Khda ludn tot nghi?p

DHIOMT- Nguvei

nhieu loai lire hut khac nhau: lire tinh dien, tan xa, cam ling va lye dinh hudng.
Lye lien kit nay yiu nen di pha va.

Trong hap phu vat ly cac phan tir cua chit bi hip phy va chit hip phu
khdng tao thanh hyp chit hoa hyc (khdng hinh thanh cac lien kit hoa hyc) ma
chat bi hap phy chi bi ngung ty tren bi myt phan chia pha va bi give lai tren bi
mat chit hip phu. Qua trinh nay xay ra d nhiyt dp thudng. d hip phy vat ly nhiet
hip phy khdng Ion thuemg bd hem 20 kJ/mol (Le Van Cat, 2002; Trdn Tit Hiiu,
2003; Trdn Van Nhdn va ctv, 2005).
b. Hap phu hoa hyc
Hap phu hoa hyc xdy ra khi cac phan tur chat hap phu tao hyp chat hoa hoc

vdi cac phan tir chat bi hip phu. Lye hip phu hoa hoc khi do la lye lien kit hoa
hyc thong thuemg (lien kit ion, lien kit cong hoa tri...). Lien kit nay manh nen
khd pha va, nhiet hip phu hoa hoc Ian va phy thuyc vao pH, ban chit axit - baza

gitta chit hip phy va chit bi hip phy (Le Van Cat, 2002; Trdn Tu Hiiu, 2003;
Trdn Van Nhdn vet ctv, 2005).
2.4.3 Hap phu trong nioi trirfrng nude
Trong nude, sy tuang tac giua chit hip phy va chit bi hip phy phuc tap
hem nhieu vi trong nude cd ba thanh phan gay tuang tac la chat hap phu, chat bi
hap phy va nude. Do sy cd mat cua dung mdi nen trong he se xay ra sy hap phy
cynh tranh giua chat bi hap phu va dung mdi tren be mat chat hap phy. Cap nao
cd tuemg tac manh thi hip phy xay ra d cap do. Tinh chyn lye cua cap tuang tac
phu thuyc vao cac yiu td nhu d0 tan ciia chit bi hip phy trong nude, tinh ua nude
hoac ky nude cua chat hap phy, muc dp ky nude cua chat bi hap phy trong mdi
trudng nude.

So vdi hap phy trong pha khi, sy hip phy trong mdi trudng nude cd tie dd
cham han nhiiu. Dd la sy tuemg tac giua chit bi hip phy vdi dung mdi nude va
vdi bi myt chit hip phy lam cho qua trinh khuich tan cua cac phan tu chit tan
cham.

Sy hip phy trong mdi trudng nude chiu anh hudng nhiiu bdi pH cua mdi

trudng. Sy thay ddi pH khdng nhttng din din sy thay ddi vi ban chit chit bi hip
phy ma con anh hudng den nhdm chiic tren be mat chat bi hap phy (L Van Cat,
2002; Trdn Tu Hiiu, 2003; Trdn Van Nhdn va ctv, 2005).
* Bete tinh ciia ion kim loai nang trong mdi trudng nude
Di tin tai duyc d trang thai bin, cac ion kim loai trong mdi trudng nude bi
hydrat hda tao ra ldp vd la cac phan tu nude, cac phuc chit hydroxo, cac cap ion

GVHD: ThS. Bui Thi Mai Phvng