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7/30/2019 NGHIN CU KH NNG HP PH Cr TRN V TRU V NG DNG X L TCH Cr KHI NGUN NC THI
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I HC QUC GIA H NI
TRNG I HC KHOA HC T NHIN--------------o0o--------------
L TH TNH
NGHIN CU KH NNG HP PH Cr TRN
V TRU V NG DNG X L TCH Cr
KHI NGUN NC THI
Chuyn ngnh: Ha Phn tchM s: 60 44 29
LUN VN THC S KHOA HC
Cn b hng dn Khoa hc: PGS.TS. Nguyn Xun Trung
H NI 2011
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M uNc l mt ti nguyn v tn, gi mt vai tr quan trng trong qu trnh hnh
thnh v pht trin sinh quyn. Khng th c s sng khi khng c nc. Nc ng
vai tr quan trng trong sn xut cng nghip, nng nghip v i sng ...
Ngy nay, cng vi s pht trin kinh t, khoa hc k thut v cuc sng
ca con ngi c nng cao, th nhu cu v nc ngy cng nhiu, nhng s
nhimmi trng nc xy ra ngy mt nghim trng hn.c bit l nhim cc
kim loi nng, nhng kim loi ny c lin quan trc tip n bin i gen, ung th,
cng nh nh hng nghim trng n mi trng ngay c hm lng nh( v d
Cr). Vi mc tiu l tm kim vt liu r tin, d kim, c th ti to c hp
ph, loi b kim loi nng trong nc l vn chng ti la chn.
V tru l ph phm ca nng nghip, r tin, d kim, khng lm ngun nc
b nhim. Mt khc Vit Nam l mt nc c ngun ph thi nng nghip di do
song vic s dng chng vo vic ch to vt liu hp ph nhm x l nc thi cn
t c quan tm, chng ti hy vng rng vt liu ny c th ng dng vo x l kim
loi nng c trong ngun nc b nhim, gp phn lm cho mi trng xanh sch
p.
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NI DUNG LUN VN
I. L do chn ti
Vi mc tiu l tm kim vt liu mi hp ph, loi b kim loi nng trong
ngun nc b nhim.
II. Mc ch nghin cu.
Tm kim vt liu r tin, d kim, c th ti to c hp ph, loi b kim
loi nng trong nc, khng lm ngun nc bin nhim.
III. Tm tt lun vnTng quan
1. c tnh ca Crom.Crom c c tnh l hc (bn nhit cao, kh oxi ho, cng v to mu
tt) nn c s dng rng ri. V vy m tc hi ca n gy ra ngy cng nhiu.
Kt qu nghin cu cho thy Cr(VI) d ch vi mt lng nh cng l nguyn nhn
chnh nh hng trc tip n sc kho con ngi. Chnh v vy, vic xc nh hmlng v loi b Crom l cn thit nhm m bo c nc sch cho sinh hot, cho
sn xut v lm trong sch mi trng.
2. Cc phng php tch loi Crom.
C rt nhiu phng php x l, tch loi kim loi nng ni chung
v Crom trong nc thi ni ring: Phng php kt ta, phng php trao i ion,
phng php hp ph... Phng php hp ph l phng php c p dng rng riv rt kh thi, vt liu hp ph a dng v phong ph. Mt trong nhng vt liu s
dng hp ph kim loi nng trong nc thi ang c nhiu ngi quan tm
l cc vt liu c ngun gc t nhin, cc ph phm ca nng nghip.
Thc nghim.
1. Chun b vt liu
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- Chun b v tru. Cn 0,5 kg v tru ra sch, un vi nc ct 2 ln nhit
300C, thi gian 5gi, em sy nhit 800C thi gian 24 gi. Sau nghin
nh vi kch thc F= 0,3 mm, em sy li v bo qun trong bnh ht m ta c
vt liu v tru (VL1).
- Chun b v tru bin tnh vi HCHO
Ly v tru ra sch un vi HCHO vi t l 200g/l nhit 30 0C, thi gian
5gi, ra sch ht HCHO bng nc ct, em sy nhit 800C thi gian 24 gi,
nghin nh vi kch thc F= 0,3 mm, em sy li v bo qun trong bnh ht m ta
c vt liu VL2.
Kt qu v tho lun
1. Ti u ha cc iu kin xc nh Crom bng phng php o quang vi
thuc th PC.
Qua kho st chng ti chn c cc iu kin ti u sau.
Danh mc cc yu t n V Gii hn v nng
Bc sng nm 540
nng axit M 4.10-2Nng thuc th % 0,008
Thi gian o phc Pht 10 45
Khong tuyn tnh ca php o ppm 0,1 1,1
LOD ppm 0,0101
LOQ ppm 0,0338
lch chun (S) 0,0027928
Phng sai mu (S2) 7,8.10-6H s bin ng ca php o CV % 0,89
2. Nghin cu kh nng hp ph Cr
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nh d nhm ch
nh d
Mu vt liu c a vo my hin vi in t qut JFM 5410 LV cahng YEOL Nht Bn thuc Trung tm khoa hc vt liu Khoa Vt l Trng
HKHTN. Cc hnh chp c l cc phng i khc nhau.
T hnh trn ta thy cc mnh v tru c cu trc xp, HCHO ph ln bao bc
cc mnh v tru v chng gn kt li vi nhau to ra cc mao qun lm tng xpca vt liu. Do vy chng c th hp ph cc ion kim loi d dng.
Ph hng ngoi c thc hin trn my GX PerkinElmer USA ca b
mn ha vt liu Khoa ha Trng HKHTN.
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Nhn vo ph hng ngoi trc v sau khi hp ph. Ta c th nhn thy d dng
khi hp ph cc nh pic thay i rt ln iu chng t cc nhm chc tham
gia qu trnh hp ph.
2.2. Nghin c t .
2.2.1. Kh
Chun b 1 dy bnh cha 0,2 g vt liu c thm cc dung dch Cr+6 20ppm vi gi tr
pH thay i 1 8, dung dch Cr(III) 19,84ppm c gi tr pH = 1 6. Tt c cc mu
u c lc vi cng tc 150 vng/ pht trong thi gian 4 gi nhit phng
th nghim. Sau em lc, xc nh nng Crom cn li bng phng php o
quang cho kt qu nh sau.
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0
0. 0
0. 5
1. 0
1. 5
2. 0
2. 5
3. 0
3. 5
4. 0
4. 5
Qe(mg/g)
v o pH dung d
Vy chng ti chn pH = 1,5 cho cc th nghim tip theo. T kt qu trn cho thy
VL2 hp ph Cr(VI) tt hn VL1.
Cr(III) b hp ph rt t trong khong pH rng. Do vy chng ti la chn pH = 1,5chung cho cc th nghim nghin cu kh nng hp ph ca Cr(VI), Cr(III) tip theo.
2.2.2.Chng ti tin hnh nh trn kho st thi gian t 10 n 210 pht. kt qu
c ch ra hnh sau.
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0 5 0 100 15 0 200
0
10
20
30
40
50
Cr(VI)
Cr(III)
q
e(mg/g)
[Cr(VI)].[Cr(III)] ppm
Hnh 3.11: h nh h
Nhn xt:T kt qu trn chng ti thy thi gian t cn bng hp ph ca
vt liu i vi Cr(VI) v Cr(III) l 8,5gi n 9 gi. Do vy cc qu trnh kho st
tip theo chng ti chn thi gian hp ph l 9 gi.
3.2.2.3. Kh
Chng ti ly cc bnh nn nh s th t, mi bnh cha 0,2 gam VL2.
Thm 100 ml dung dch Cr(VI) v Cr(III) c nng khc nhau, iu chnh pH= 1,5.
Lc 9 gi vi tc dng 150 vng/pht, nhit phng th nghim. Sau xc
nh nng d Crom cn li bng phng php o quang vi thuc th PC. Cho Kt
qu sau.
n VL2
T kt qu trn chng ti xc nh dung lng hp ph cc i v hng s
Langmuir.
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y = 0,0168x + 0,508
y = 0,2857x + 1,7324
0
5
10
15
20
25
30
35
0 20 40 60 80 100 120
Cr(VI)
Cr(III)
Khi tnh c gi tr hng s Langmuir v dung lng hp ph cc i.
i vi Cr(VI): tga = 1/qmax qmax = 1/tga = 1/0,0168 = 59,52 (mg/g)
b = 1/K.qmax K = 1/b.qmax = 1/0,508*59,52 = 0,033
i vi Cr(III): tga = 1/qmax qmax = 1/tga = 1/0,2857 = 3,5(mg/g)
b = 1/K.qmax K = 1/b.qmax = 1/1,7324*3,5 = 0,16493.2.2.4. Kh h c
kho st nh hng ca cc ion ti kh nng hp ph ca Cr(VI), Cr(III)
ln vt liu (VL2). Chng ti chun b cc bnh nn, cho cc dung dch kho st
nh ni trn c thm cc cation em lc tc 150 vng/pht. Sau 9h, xc
nh nng Crom cn li trong dung dch bng phng php o quang. Kt qu
thu c di y.
* nh hng ng thi ca cc ion Cu2+ ,Ni2+ ,Fe3+, Zn2+
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Hnh 3.18: Cr(III) khi c m2+
, Ni2+
, Fe3+
, Zn2+ .
T kt qu trn ta thy, khi c mt mt lng ln cc ion kim loi c bit lcc ion kim loi nng th dung lng hp ph Cr gim.
3.2.3. Kh
3.2.3.1. Kh i c
Cho 1,00 gam VL2 vo ct hp ph c chiu di 8cm, ng knh ca ct
0,8cm v c nh v trn gi hp ph. Dung dch Cr(VI) nng 10ppm, Cr(III)
nng 9,82ppm pH=1,5 c chy lin tc qua ct vi tc 1ml/pht cho ti
khi nng Crom i ra khi ct bng nng i vo th dng li. Gii hp lng
Crom b gi trn ct bng 30ml HCL2M/H2O2 0,1%. Xc nh lng Crom c ra
gii bng phng php o quang vi thuc th PC. Kt qu thu c dung lng
hp ph cc i i vi Cr(VI) l 62,5mg/g, Cr(III) l 2,85 mg/g.
3.2.3.2. Kh
Chng ti tin hnh nh trn v thay i nng cht ra gii HCl t 0,5 n
3M cho kt qu sau.
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i o n
Nhn xt: Nhn vo bng kt qu ta thy tc nhn ra gii l HCl 3M l tt
nht nhng nng ny d lm phn hy vt liu. Do vy chng ti chn tc nhn
ra gii l HCl 2M/H2O2 0,1%
2.3.3. Kh
Cr(VI) ln v
Chun b cc ct hp ph cha 1,00gam VL2. Cho cc dung dch cht phn
tch trn chy qua ct hp ph vi cc tc khc nhau t 1 - 5ml/pht. Sau ta
tin hnh ra gii bng 30,0 ml HCl 2M/H2O2 0,1%. Thu ton b dung dch ra gii
em xc nh Cr(VI) bng php o hp th quang. Kt qu thu c hnh sau
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Hnh 3.20: o t
T kt qu trn ta thy nu duy tr tc t 0,5 1,5ml/pht l thch hp. Tuy
nhin tc qu chm th tn nhiu thi gian. Do vy chng ti chn tc np mu
l 1,0 ml/pht cho cc nghin cu v sau.
2.3.4. Kh
Hnh 3.21 ph o th
Nhn vo kt qu trn ta thy th tch ra gii tt nht l 30ml HCl2M/H2O2 0,1%.
2.3.5. Kh
Hnh 3.22: o t
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Nhn xt: T kt qu trn ta thy tc ra gii 0,5 ml/pht l rt tt, nhng
tc qu chm mt nhiu thi gian. Do vy chng ti chn tc 1,0 ml/pht cho
cc nghin cu tip theo.
3.2.3.6. Kh
Cr2O72-
trn VL2
chng ti tin hnh kho st nh hng ca mt s ion nh: Na+, K+, Ca2+,
Mg2+, Ni2+, Zn2+, Mn2+, Pb2+, Cd2+, Al3+, Fe3+. Di y l cc kt qu thu c:
T kt qu thc nghim ta thy vi nng ln cc ion Zn2+, Cu2+, Co2+,
Ni2+, Fe3+ th mi gy nh hng ti hiu sut thu hi. Vi Zn2+, Cu2+, Ni2+ nh
hng ng k khi nng ion ny hn nng Cr(VI) 1000 ln, Vi ion Co2+, Fe3+
th nh hng khi nng ny hn nng Cr(VI) 500 ln.
3.3. Th nghim x l mu gi v kho st kh nng ti s dng vt liu
Chn b mu gi c cc thnh phn nh mu tht
Bng : Kt qu hp ph tch loi Crom ca dung dch mu gi
Thnhphncht
Lng banu
( mg/l)
Tng lngBan u
( mg/l)
Lng Crm hp ph
( mg/l)
LngCrom cn li
( mg/l)
Hiu suthp ph
(%)
Cr(VI) 90
100
98,921,08
98,92
99,15 0,85 99,15
Cr(III) 10 97,42 2,58 97,42
99,08 0,92 99.08
98,73 1,27 98,73
Nhn xt: T kt qu trn c th kt lun vic s dng v tru bin tnh lm
vt liu hp ph crom trong nc thi t hiu sut hp ph cao, c kh nng ng
dng vt liu ny tch crom khi ngun nc thi.
* Nghin cu kh nng ti s dng vt liu
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Sau mi ln hp ph, ra gii. Chng ti tin hnh hp ph v gii hp nhng ln
sau nh ln 1. Kt qu thu c nh sau.
S ln s dng vt liu 1 2 3 4 5
Hiu sut hp ph (%) 100 92,65 81,36 69,37 42,63
T kt qu bng trn, chng ti thy vt liu c kh nng ti s dng cho nhng
ln sau, tuy nhin hiu sut hp ph gim dn. V vy cn nghin cu cc bin php
s l thch hp ti s dng vt liu khi x l ngun nc thi cha Crom.
3.4. Th nghim x l mu nc cha Crom
c kt qu chnh xc v hm lng Crom trc v sau khi x l. Chng
ti gi mu phn tch bng phng php ICP-MS, xc nh tng lng crom ti
phng my Khoa ha hc Trng i hc khoa hc t nhin i hc Quc gia H
Ni. Kt qu thu c ghi trong bng sau.
Bng : Kt qu th nghim x l mu nc cha Crom
Tn mu ncK
hiu
Lng Crmtrc khihp ph
( mg/l)
LngCrm hp ph
( mg/l)
LngCrmcn lisau hp
ph
( mg/l)
LngCromc
loi b
(%)
Nc thi Cng ty
Nhm Sng Hng -Vit Tr - Ph Th
VT1 76,43 74,87 1,56 97,95
VT285,89 84,19
1,70 98,02
VT3 81,75 79,97 1,78 97,82
Nc thi Cng ty
Ha cht Z121 - Ph
Ninh Ph Th
VT5 29,81 29,25 0,56 98,12
VT6 28,37 28,08 0,29 98,97
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T kt qu nghin cu x l mt s mu nc cha Crom cho thy, hiu
sut tch loi Crom ca v tru kh cao (trn 90%). T ta c th kt lun v trin
vng ng dng vt liu v tru bin tnh tch loi Crom khi ngun nc thi.
KT LUN
Sau qu trnh nghin cu hon thnh lun vn thc s vi ni dung ti:((Nghin cu kh nng hp ph crom trn v tru v ng dng x l tch crom
khi ngun nc thi )). Chng ti thc hin c mt s cng vic sau:
1. nghin cu ti u ha cc iu kin xc nh Crom bng phng php trcquang vi thuc th iphenylcarbazid.
Cc iu kin ti u xc nh Crom bng thuc th PC nh sau:
- Ph hp th nh sng ca phc mu t cc i bc sng 540 nm, nng
axit H2SO4 4.10-2M, nng thuc th 0,008 %...
- Kho st nh hng ca cc ion n hp th quang ca phc mu.
- Tm c khong tuyn tnh ca php o: 0,1 1.1ppm
- Xy dng ng chun xc nh Crom
- Tm c: Gii hn pht hin l 0,01ppm
Gii hn nh lng: 0,03ppm
2. nghin cu cc yu t nh hng n qu trnh hp ph Cr(VI), Cr(III) trn vt
liu VL1 v VL2:
- pH = 1,5, thi gian hp ph l 9 gi.
- kho st c nh hng ca nng u v tm c dung lng hp
ph i vi Cr(VI): 59,52 (mg/g) Cr(III): 3,5(mg/g)
- Kho st c nh hng ca cc ion kim loi n kh nng hp ph ca vt
liu.
3. kho st kh nng hp ph Cr ca vt liu iu kin ng:
- Dung lng hp ph cc i i vi Cr(VI) l 62,5mg/g, Cr(III) l 2,85 mg/g.
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- Tc hp ph l 1,0ml/ pht, tc ra gii l 1,0ml/ pht
- Th tch dung dch ra gii 30ml HCl vi nng 2M + H2O20,1%.
- Kho st nh hng ca mt s ion cn tr n kh nng hp ph.4. p dng th nghim x l mt vi mu nc thi cha Crom.
Vi nhng g lm c trong bn lun vn ny, chng ti hy vng y l
mt ti hu ch cho vic p dng x l mu nc thi cha Crom. Qua nghin
cu chng ti kt lun rng c th s dng vt liu v tru bin tnh hp ph
x l tch Crom khi ngun nc b nhim.
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