TAP CHI HOA HOC T. 49(2)138-141 T H A N G 4 N A M 2 0 1 1
K H A
NANG
H A P P H U P H A M M A UALIZARIN
V A N G GCUA VAT LIEU COMPOZIT TIJ TiNH Fe304 NANO/CACBON HOAT TINH
Bill Thj Thai, Nguyen Xuan Hoan
Khoa I Ida hoc. Trinhig Dgi hgc Khoa hpc Tu nhien, Dgi hgc Quoc gia Hd Ngi Din Tda soan 01-04-2009
Abstract
Magnetic FciOj/activated carbon composite have been prepared by hydrothermal reaction with homogeneous inorphology. The value of saturation magnetization Ms > 10 emu/g was obtained. Langmuir isotherm model was used to investigate the adsoprtion of Alizarin yellow-G dye on FcjOj/activated carbon composite. Results showed that the maximum adsorption capacities q,,,,, were higher than 350 ing/g.
1. MO DAU
Dung djch nude thai trong cdng nghiep nhugm chira mdt lugng Idn pham mau nen ddi hdi can phdi dugc xir ly hodc thu hdi trudc khi thai ra moi trudng [1, 2]. Cdc hat tir tinh irng dung de xir ly cdc van de mdi trudng nhan dugc nhieu su quan tdm trong nhung nam gdn ddy. Dugc dung tao compozit vdi cdc vat lieu hap phu nen sau khi hap phu, cd the tdch khdi mdi trudng bang quy trinh don gidn bdng viec sir dung tir trudng ngodi nhd mgt nam chdm. Cdc hat compozit tir tinh cd the dugc diing de hdp phy cdc chat d nhiem tir trong nude: cdc chat d nhiem hQ-u co nhu thuoc trir sdu, phenol, clorobenzen, cloroform, cdc phdm mdu hiru co, asen, hdp phu cdc cation kim loai hay cdc chdt khi thdi,... [3 10].
Phdm mdu Alizarin vdng G Id hgp chat dugc sir dung chii yeu trong ngdnh cdng nghiep det nhugm d Viet nam; thugc nhom hgp chat azo cd cdng thirc phdn tir Ci3H8N3Na05: 2-hydro.\y-5-((3- nitrophenyl)azo) benzoic axit natri. Trong nghien ciru ndy, chung toi da tien hdnh tong hgp vdt lieu compozit tir tinh Fe304/cacbon boat tinh bang quy trinh tong hgp thuy nhiet vd lua chgn Alizarin vdng G de nghien ciru khd ndng hap phy cua no tren vat lieu hdp phu compozit tir tinh FejOVcacbon boat tinh.
2. THUC NGHIEM
Cdc hoa chat chinh dugc sir dung trong nghien ciru gom: FeCl3.6H20 (> 99%), FeS04.7H20 (>
99%), KOH (> 82%), NaOH (> 96%), HNO3 (65 68%), con tiiyet doi (99,5%), cacbon boat tinh vd pham mdu Alizarin vdng G.
2.L Dieu che compozit tir tinh FejOycacbon hoat tinh
Cacbon boat tinh dugc tinh che lai bang cdch ngam tam ldn lugt trong cdc dung djch NaOH vd HCI, rira sach bang nude cat, sdy khd vd bdo qudn trudc khi dem sir dung.
Hda tan hai muoi Fe(II), Fe(lll) vdo mdt lugng nude vira du tren may khua\ tu. Tiep den, them cacbon boat tinh theo ti le [Fe(ll),Fe(lIl)]/C = 1/3.
Dimg KOH dieu chinh hdn hgp phdn img den pH - 12. Chuyen todn bd hdn hgp phdn irng vdo binh thiiy nhiet. ldi bdng Teflon, vd dem xu ly nhiet [11]. Sdn phdm thu dugc sau phdn img dugc rira sach de loai tap chdt, Igc va sdy khd.
Sdn phdm sau khi tdng hgp dugc nghien ciru cdc dac tinh vd tinh chat: Xdc dinh pha bang nhieu xatia A'tren thiet bj nhieu xa D8 Advance Bruker (AcuKa'^
1,5418 A, 20 steps = 0,03°/step). Hlnh thdi hgc hat vat lieu dugc quan sdt tren kinh hien vi dien tir quet phdn gidi cao HITACHI S-4800. Phdn tich nhigt vi sai (TG/DTA) cdc mdu dugc thuc hien tren thiet bj SETARAM TG-DTA 92 (tdc do gia nhiet
10°C/phiit, khi quyen khdng khi). Do tir hda bao hda ciia vat lieu tir tinh xdc djnh tren thiet bj tir ke mdu rung DMS 880.
2.2. Nghien ciru kha nang hap phu ciia vat lieu compozit tir tinh FesOVcacbon hoat tinh doi vdi pham mau Alizarin vang G
Thdi gian can bang hap phu ciia vat lieu hdp phu ddi vdi chat dugc hap phy dugc chung tdi xdc djnh bdng thuc nghiem Id sau 1 gid.
De xdc dinh khd nang hap phu cue dai cua vat lieu, chiing tdi tien hdnh khdo sat qud trinh hap phu 138
1 v^MH, 1. ^ ^ i . / ; , / U 1 1 Khd ndng hdp phu phdm mdu...
Alizarin vdng G d dieu kien nhiet do 25°C. Nong dg dau cua chdt bj hap phy (Co) thay doi tir 100 -H 2000 mg/L dung djch. Lugng vat lieu hap phy dugc sir dyng trong mdi thi nghiem Id 0,10 gam trong binh non chiia 100ml dung djch Alizarin vdng G (pH = 6 -^ 7). Todn bd hdn hgp tren dugc khudy diu trong 30 phut vd de yen trong 3 gid. Sau dd, thu Idy dich Igc vd xdc djnh lai ndng do phdm mdu bang phuang phdp do quang tren thiet bj trdc quang UV-Vis Hach D-4000 tai budc sdng cue dai 415 nm. Cdc ket qud thuc nghigm dugc xir ly tren co sd phuang trinh ly thuyet hdp phy Langmuir.
3. KET QUA vA T H A O LUAN
bdo hod thap han ban so vdi mau Fe304 dieu chl trong cimg dieu kien. Gid trj dg tir hod bdo hod {Ms) cua Fe304, MB vd MBH lan lugt Id: 80,65 emu/g,
11,59 emu/g vd 10,21 einu/g; so vdi gid trj 2,78 emu/g trong nghien cuu ciia N. Yang [3], vd 12,4 emu/g cua Z. Wang [12] ddi vdi vdt lieu compozit Fe304/cacbon boat tinh. Anh chyp SEM cua vdt lieu compozit Fe304/cacbon hoat tinh (MB, MBH) cho thdy cdc h^t Fe304 phdn tdn ddng deu tren be mat cua cacbon boat tfnh vd cd dg ddng nhdt cao vdi kich thudc h^t trung binh nhd ban 40 nm (hinh 3).
Ket qud tren hodn todn phii hgp vdi nhu-ng nghien ciiu CLia cdc nhdm tdc gid N. Yang [3], L. C. A.
Oliveira [4], vd Q. L. Zhang [9].
3.1. Vat lieu Fe304, compozit tir tinh Fe304/cacbon hoat tinh
Cacbon boat tinh Id vat lieu hdp phy dugc sir dung rgng rai trong cdng ngh igp vdi cdc uu diem cd do ddng nhdt cao, dien tich be mat rieng Idn, cdu triic vi mao qudn vd ben vung [2, 4]. Sir dyng cacbon boat tinh nhu vdt lieu nen, bdng phuang phdp thiiy nhiet, chiing tdi da tdng hgp mdu bgt Fe304 vd hai dang mdu compozit tir tinh Fe304/cacbon boat tinh: mdu 1- sir dyng true tiep bdt cacbon boat tinh sau xir ly (ky hieu Id MB); mdu 2- sir dyng cacbon hoat tinh sau xir ly vd dugc boat hod tiep vdi HNO3 trudc khi trgn phdn ling (ky hieu Id MBH).
Gidn do nhieu xa tia X cua vat lieu vdi cdc pic ddc trung cho pha Fe304 (hinh 1), chiing td vat lieu Fe304 thu dugc bdng phuang phdp dieu che thiiy nhiet co do tinh khiet cao. Tren hai mdu compozit MB vd MBH thdy su cd mat cua cdc pic ling vdi pha Fe304 ben canh cdc pic ddc trung cho pha cacbon.
29(°)
Hinh T. Gidn dd nhieu xa tia X cdc mau theo thOr tu Fe304, MB vd MBH
Do tir hoa bao hda cua vat lieu dugc xdc djnh tir cdc dudng cong tir hda d nhiet do phdng (hinh 2).
Hai mau compozit tir tinh MB vd MBH cd do tir hod
E
0) 100
80 60- 40- 20- 0 -20 -40 H -60 -80 -100
-Fe304 -MB
-MBH /•
.•..•.^*..«=»-*=«***'
1^
I m
l = ^ f t = : t = f t - - > ' A = l = ' = ' = • " « = •
J
•f
2000 4000
H ( O e )
-15000 -10000 -5000 0 5000 10000 15000 H(Oe)
Hmh 2: Dudng cong tir hod cdc mdu theo thiir tu Fe304, MB vd MBH
3.2. Khao sat kha nang hap phu ciia vat lieu Fe304, compozit Fe304/cacbon hoat tinh
Cdc ly thuyet hdp phu ddng nhiet Freundlich, Langmuir vd BET thudng dugc su dung de nghien cuu cho cdc qud trinh hdp phy. Thuc nghiem chi ra rang, ly thuyet hdp phy ciia Langmuir cho ket qud gdn diing ban cd trong trudng hgp vdt lieu hdp phu Id cacbon hoat tinh vd cdc vat lieu bj hdp phy thudng Id cdc pham mdu [2, 3]. Phuang trinh (1), (2) Id cdc dang cua phuang trinh Langmuir:
q = q b.C,
max-l + b.Cg (1) C,
^ b.q
max max
cd dang Y = A.X +B (2)
Trong do: q Id lugng chat bj hdp phy bdi 1 gam chdt hdp phu (mg/g), b Id hdng sd hap phy Langmuir (L/mg), CI; Id ndng do chdt bj hdp phu liic cdn bdng 139
TCHH, T. 49(2), 2011 hap phy (mg/L), q„
(mg/g)-
la dai lugng hap phy cvrc dai
Khd ndng hap phy ciia vdt lieu compozit Fe304/cacbon boat tinh (MB, MBH) doi vdi pham mdu Alizarin vdng G dugc khdo sdt trong dung djch nude. Hinh 4 Id do thj bilu dien sg phy thugc ciia Ci./q vdo Cl, (phuang trinh 2) vd dudng hap phy dang nhiet Langmuir cua cdc vdt ligu hap phy cacbon boat tinh, MB vd MBH dugc xir ly tir cac ket qud thgc nghiem.
Hmh 3: Anh chup SEM mdu vat lieu Fe304/cacbon hoat tinh (mdu MB)
700 600
^ 500
!> 400 O- 300 200 100
*^v\. \
^ ^ _ _ _ _ _ _ ( 3 )
::iii^^(2)
(1):MBH (1) (2): MB (3): C
400 800 1200 1600 2000 2400 C, (mg/L)
Hinh 4: Dudng hdp phy ddng nhigt Langmuir ciia cdc vdt lieu hap phy
Cdc dudng thdng ddng nhigt hap phy thu dugc vdi hg sd hdi quy thuc nghigm tuyen tinh R^ cd dg tin cay tuong ddi cao. Kit qud khdng djnh sg hap phy pham mdu Alizarin vdng G tren nen vat ligu cacbon hoat tinh vd compozit Fe304/cacbon hoat
^tinh Id hdp phy hda hgc vd tuan theo ly thuyet hdp phy dang nhiet Langmuir. Cdc hg sd A, B cua phuong trinh (2) vd cdc hdng so bilu thj cho phuang trinh hdp phy Langmuir q„.,ax, b dugc tdm tdt trong bdng 1.
Hang sd hap phu Langmuir b rat nhd gidi thich
Bill Thdi va cgng su su tirong tdc m^nh giira chat hdp phy vd chat bj hap piiu. Khd nang hdp phy cua cdc vdt lieu hap phu cacbon ho^t tinh, MB, MBH gidm ddn vd gia tri hap phy cgc d^i q,„ax, ^ ^'eu kign ddng nhigt 25°C, tuong ling lan lugt Id 565, 505, 355 mg/g; so vdi gia tn q„„„ = 35 mg/g do dugc tren vdt ligu bgt Fe304 trong cii'ng dieu kign thgc nghigm. Sg gidm manh gid trj
^„,„,tren vdt ligu compozit MBH so vdi vat lieu MB cho thay vigc bo^t hda bdng HNOj ddi vdi vat ligu cacbon ho^t tinh trudc khi trgn hdn hgp phdn irng t^o compozit Fe304/cacbon hoat tinh hodn todn khdng cd Igi cd vl mat tinh chat tir tinh vd khd ndng hdp phy ciia vdt ligu doi vdi pham mdu Alizarin vdng G. Cd the gidi thich tren co sd khi boat hda bdng axit IINO3, se tao cdc tdm boat dgng ua nude trong cau triic mao qudn vd tren be mat cua cacbon hoat tinh nhu dd chi ra trong nghien ciru cua N.
Yang ciing cgng sg [3]. Do dd, nd de dang ldi keo cdc chat phdn Orng nhieu han hodc gdn trgc tiep tren bl mat, hodc di sdu vdo trong cau triic mao qudn cua cacbon ho^t tinh dl tao cdc hat nano Fe304, nen ldm gidm dign tich bl mat rieng, tu do gidm khd ndng hap phy cua vdt ligu. Hinh 5 Id cdc dudng phdn tich nhigt khoi lugng (TG) cho vdt ligu Fe304, MB vd MBH thuc hign trong khi quyin khdng khi.
Bdng T. Hdng so trong phuang trinh ddng nhiet hdp phy Langmuir cua cdc vdt lieu hdp phy khdc nhau
ddi vdi phdm mdu Alizarin vdng G
'"hoai tinh
MB MBH
A^ 10*
177±6 198±6 283±39
5 x 10^
49,68 84,61 120,04
R^
0,992 0,994 0,914
qmaxt
mg.g' 565±20 505±15 355±40
b, L.mg"'
0,036 0,023 0,024
0 -
^ - 1 0 - 0 1 - - 2 0 -
-30-
- 4 0 -
- 5 0 - +1.7%
• ^ -
^ N v . MBH
-43,0%
FeP4
1
^ ^ N . -29,9%
^\\l
\ M B
200 400 600 800
Nhiet do (°C)
1000
Hinh 5: Gidn dd phan tich nhiet (TG) cua cdc mdu Fe304, MB va MBH
Vdi vat ligu Fe304, tren dudng TG cd s\r tang 140
iCHri, 1.49(2), 2011 Khd ndng hdp phi,!phdm mdu..
khdi lugng ~ 1,7% tuong ling vdi qud trinh oxi hda hodn todn Fe304 thdnh Fe203 nhu da chi ra trong nghien ciiu trudc [11]. Vdi vdt ligu compozit MB vd MBH, khi thieu kit din nhigt do 900°C, vat ligu MB cd su hyt khoi lugng nhilu hem 13,1% so vdi vdt ligu MBH. Gid trj ndy tuong irng vdi su chenh Igch vl hdm lugng cua oxit sdt tren vdt lieu MBH nhieu han so vdi vdt ligu MB. Kit qud ndy gdp phan ldm sdng td ludn cir dd neu tren.
4. KET LUAN
Sii dung phuang phdp thiiy nhigt vdi quy trinh don gidn, vdt lieu Fe304 vd vdt lieu compozit tir tinh nano Fe304/cacbon boat tinh da dugc tdng hgp. Sdn pham thu dugc cd do ddng nhdt cd hat cao vdi kich thudc hat trung binh nhd hon 40 nm. Ddi vdi cdc vdt lieu compozit tir tinh Fe304/cacbon hoat tinh, cdc hat tir tinh phdn tdn deu tren be mdt vd trong mao qudn ciia cacbon boat tinh vd cd dg tir hda bdo hda Ms> 10 emu/g. Cdc vdt lieu compozit Fe304/cacbon boat tinh deu hdp phy tdt phdm mdu Alizarin vdng G trong dieu kien nghien ciiu. Cdc ket qud thuc nghiem chiing td qud trinh hdp phu phdm mdu Alizarin vdng G tren cdc vat lieu hdp phy tudn theo ly thuyet hdp phy ddng nhiet Langmuir. Do hdp phy cue dai cua cdc vdt lieu gidm theo thir tu: cacbon hoat tinh > MB
> MBH > Fe304.
Ldi cam on: Bdi bdo ndy duac hodn thdnh vdi su giiip da kinh phi cua de tdi Nghien cuu che tgo mdt
sd dgng vdt li?u compozit tir tinh, md sd QT-08-19.
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Lien he: Nguyen Xuan Hoan Khoa Hda hgc
Trudng DHKHTN, DHGQ Hd Ndi 19 Le Thdnh Tdng, Hodn Kiem Hd Ndi Email: [email protected]
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