TAP CHi HOA HQC T. 50(3) 269-272 THANG 6 NAM 2012
NGHIEN CCru T 6 N G HQ-P Z E O L I T NaY KlCH THU'dC NANO TLP CAO LANH A LU'&I VIET NAM
Huynh Thj Thanh Hutrag', [Pham Vfin H a i \ Tp Ngflc D6n''
^Bg mon Hoa hgc. Trudng THPTPhan Chdu Trinh. Bd Ndng
^Dgi hgc Dd Ndng
^Khoa Cong ngh? hod hgc, Trudng Dgi hgc Bdch khoa Hd Ngi Din Tod sogn 20-8-2010
Abstract
NaY zeolite with crystal size of 22 nm has been synthesized from Vietnamese A Luoi kaolin in hydrolhermal ciystallizing condition with the present of DNy template. Results obtained from XRD, IR, SEM, TEM, BET prove that NaY has high crystal Unity, high surface area, pore size distribution in both microporous range (0.81 nm) and mesoporous range (12 nm).
Keywords; Nanozeolite, zeolite, kaolin.
1.GI0ITH1$U
Trong nhung ndm gdn day, zeolit NaY kich thude nanomet (nano-zeolit NaY) da dugc tong hgp vdi myc dich tdng dien tich be mat ngoai va md rpng pore thii cap d vimg mao qudn trung binh. Khi ay, nhd hieu irng dde biet eiia vat lieu kich thudc nanomet, nano-zeolit NaY khdng nhiing tang khd nang img dyng trong nhiing ITnh vyc truyen thong ldm chat xuc tdc vd chat hdp phu, ma cdn md rpng khd nang iing dyng trong vat lieu quang dipn tir, cam biln hda hpc vd dugc pham [I].
Cho den nay, cac cong trinh cdng bo tdng hgp thdnh edng nano-zeolit NaY hdu hit diu di tir dung djch ^el sgch, vdi sy cd mat cua mgt lugng du chat tgo cau triic trye tiep. Cde dung djch nay thudng dugc tao ra bang each sir dung cae ngudn silic vd nhdm rieng biet, de hda tan; diing mgt lugng kiem vira dii de hoa tan lugng silic va nhdm [2]. Chat tgo cau true hiru ca thudng la TMAOH (tetrametylamoni hydroxit) [3-8]. Qua trinh ket tinh thudng qua nhieu budc: Ddng the hda d nhiet dg phdng trong thdi gian tir 72-144 gid [3, 8], kit tinh thiiy nhiet d nhiet do dOT trong thdi gian tir 24-48 gid [6, 7] va d gS-IOO^C trong thdi gian tir 24-216 gid [3-5,7]. Mgt so cdng trinh cdng bd cd bo sung them NaCl [ 1 ] hay TMABr (tetrametylamoni bromua) [3, 9] nhu mpt nhan td de dieu ehinh kich thudc hat. San pham thu dugc cd bl mgt rieng tir 404-757 mVg [4-6], trong do bl mat ngoai tir 72-178 mVg [5, 6]. Kich thudc hat tir 20-80 nm [5, 6, 9].
Cac cone trinh da cdng bd tren day eho thay viec
tong hgp nano-zeolit NaY dugc tien hanh trong nhiing dilu kien nghiem ngdt vl cdng nghp va chi phi cao.
Bai bdo ndy trinh bay phucmg phap mdi ve tong hgp nano-zeolit NaY tir cao lanh A Ludi Viet Nam - ngudn nguyen lipu ran chira ddng thdi cd silic va nhom - trong nhimg dieu kipn dan gidn ve edng nghp nhung chi phi thdp.
2. THUC NGHIEM
Cao lanh A Ludi sau khi lay tir md ve, dugc Igc rira het eat, sdi va say khd. Tiep tyc xir ly mau cao lanh da so chi bdng dung dich axit HCl 4N theo ty Ip ran/ldng = 2/3 (§/ml) trong 6 gid d nhiet dg 90*'C, sau do Ipe riia den het ion Cl" roi say trong 2 gid d IIO^C; nung trong 3 gid d 650°C, ap suat thudng, thu dugc mau metacaolanh. Mau metacaolanh nay dugc trgn vdi natri hydroxit, natri clorua, thuy tinh ldng, chat tao cau triic hiiu ca (DNy) va nudc eat theo ty Ie moi 3,5Na3O.Al2O3.7SiO2.70H2O.3NaCl.l,2DNy, sau dd lam gia hdn hgp nay d nhipt do phdng trong 144 gid cd khudy trgn vd ket tinh thuy nhipt d nhiet dp 80°C trong 72 gid khong khuay trpn.
Sdn pham sau ket tinh dugc rira bang nudc cat den khi nudc riia eo dp pH = 8; say kho d nhiet do 110°C, cudi cimg nghiin va tgo ra hat cd c5 hat
< 0,15 mm. Mau dugc ky hipu la Nano-NaY.
De so sanh, mau Nano-NaY dugc phan tich trong cimg dieu kien vdi mdu zeolit NaY chudn ciia Phap (dugc tdng hgp tir hda chat tinh khilt trong
TCHH, T. 50(3). 2012
dilu kipn thong thudng), ky hipu Id Micro-NaY.
Mau Nano-NaY vd Micro-NaY dugc d$c (rung frong ciing cdc dilu kipn bdi phuang phdp nhilu xa tia X (XRD) tren mdy SIEMENS D5005 (Dire); phd h^p thy hong ngogi (IR) Ircn mdy IMPACT FTIR 410 (Dire); chyp dnh hiln vi di|n tii (SEM) tr6n mdy JSM 5410 LV (Nh$t Ban), chup dnh hi^n vi diCn tii truyln qua tren mdy JEM 1010 (Nhdt Bdn); xdc djnh bl mdi rieng (BET) trfin he COULTER SA31()0 (My). Ty Ip SiOj/A^Oi trong mau dugc xdc djnh bdng phuang phdp nung chay vd chuiin dO EDTA.
3. K 6 T QUA VA THAO LUAN 3.1. Ket qud phdn lich phd XRD
Kll qud phan tich phi XRD ciia mSu Nano-NaY vd Micro-NaY dupe trinh bdy tren hinh 1. Tir hlnh lb cho th4y, mSu Micro-NaY chi xu^t hi^n mpl pha duy nhSt CO cdng thiic l,03Na2OAl2O3-3,RSiO;8H2O img vdi zeolit NaY, ma s6 lini thi PDF 38-0240. Phd XRD ndy cho ducmg nin phdng, pic cd cudng dp rat mgnh vd sdc net. D$c bi§t, pic dgc trung cd dg rgng chdn pic rat
Tg Nggc Don vd cgng sif nhd. Cdc yiu t l trfen dd xdc nh§n mau Micro-NaY cd dO linh thi 100% vd hgt tinh the c6 kich thudc Idn.
Tren hinh la, pho XRD cua mau Nano-NaY dd xdc nh$n b€n cgnh pha tinh thi: cd md so PDF 38- 0240 cdn xuat hipn vcl tgp chat theo vdo tir nguyen lipu ban d4u la phlogopit cd md s6 PDF 02-0053, edng thiic KMg3(AlSi030io)(OH)2. Pho XRD ndy CO dudng nin cao, pic ddc trung cho zeolit NaY chi cd d$ cao khodng 53% so vdi pic d$c tnmg ciia /colit NaY trong mlu Micro-NaY vd chan pic rpng, Dieu dd ghi nh&n mlu nay c6 kfch thuac rat nhd. Tir ket qud xdc djnh dp r$ng trung blnh FWHM qua pho XRD, kich thudc hgt tinh thi zeolit NaY fieo cdng Ihirc Scherrer trong mau Nano-NaY vd M cro-NaY dugCjXdc djnh tuang img bdng 19 vd 400 nm.
3.2. Ket qud phdn tich dnh SEM vd TEM Kit qud chyp dnh SEM ciia mau Nano-NaY va Micro-NaY iri-n hinh 2 da cho thiy cd hai mau diu kcl tinh lot. tinh thi zeolii NaY tgo thdnh cd dgng hinh Igp phuang rat ddng deu, nhung kich thudc do dugc tuong img bdng 165 vd 620 nm. Tren hinh 3, kich thudc tinh thi zeolit NaY trong mlu Nano-NaY do dugc theo TEM bdng 22 nm.
(a)
(b)
Hmh 1: Pho XRD ciia mau Nano-NaY (a) dugc tdng h(;jp tir cao lanh va Micro-NaY Phap (b) dupe t6ng hpp tti hoa chit tinh khift
Hinh 2: Anh SEM ciia mau Nano-NaY (a) dupe t6ng h(;lp tir cao lanh va Micro-NaY Phap (b) dupe tdng hpp tir hoa chat tinh khiet
Hmh i: Anh TEM cua mlu Nano-NaY dupe tong hpp tir cao lanh Ket qua do kich thupc hat tinh the trong mau
Nano-NaY theo eac phuong phap XRD va TEM tucmg img bang 19 va 22 nm da chimg to tinh the
trong mau t6ng hpp rat nho, kha dong dSu va nSm trong thang do nanomet. Tuy nhien, kich thupc hat tinh the xac dinh theo phirong phap TEM va SEM
TCHH, T. 50(3), 2012
cua mau Nano-NaY rat khdc nhau (tuang iing bdng 22 vd 165 nm) dugc gidi thich Id do dO phan gidi thap ciia phuang phdp SEM so vdi phucmg phdp TEM, do ban chat ciia hai phuang phdp (SEM cho hinh anh phan xg, cdn TEM cho binh anh truyln qua mlu phan tich), hay kich thudc tinh thi theo SEM chi Id kich thudc hinh hgc. Trong khi dd, mdu Micro-NaY ludn cho kich thudc tinh thi ndm trong thang micromet.
3.3. Ket qua phan tich pho IK vd ty Ip SiOi/AliOj
^ a )
. 113oN
1 1 3 4 ^ 1012 ;
1015
778 698
780 G99 570 V
\ 466
570 \J 465
Hinh 4 Phd IR ciia mdu Nano-NaY (a) dugc tong hgp tir cao lanh vd Micro-NaY Phap (b) dugc
tdng hgp tir hda chat tinh khiet Tren hinh 4, kit qud phdn tich phd IR eiia mdu Nano-NaY vd Micro-NaY ghi nhgn biic tranh pho rdt gidng nhau, chiing td chung ed ciing kieu cau triic cua zeolit NaY. Ddm phd 570 em"' dac trung cho dao dgng cua cdc vdng kep 6 canh phan anh trang thdi tinh the ed cudng dp manh xap xi nhau da chiing td do tinh the zeolit NaY trong hai mau khac nhau khdng nhieu (bang 95% d mau Nano-NaY so vdi 100% d mau Micro-NaY theo XRD).
Tuy nhien, cac ddm phd d vung 778 va 698 cm' (trong mau Nano-NaY) dde trung cho eac dao dgng ddi xiing ciia T-O-T trong vd ngodi tii dien TOj (T: Si, Al) cd cudng dg yeu han cae dam pho tuang img d viing 780 vd 699 cm"' (trong mau Micro-NaY) do kich thudc tinh thi trong mdu Nano-NaY nhd han trong mau Micro-NaY.
Kit qua phdn tich hda hgc ty le Si02/Al203 trong
Nghien cihi long hgp zeolit NaY...
mau Nano-NaY vd Micro-NaY tuong irng bdng 3,93 vd 3,82 cho thay, mlu Nano-NaY cdn chii'a m^t lugng nhd Si02 trong cau true ciia phlogopit nhu Id tgp chat theo vdo tii nguyen lipu ty nhien ban dau.
3.4. Ket qua xdc djnh be mdt rieng vd phan b l to xop thco phuong phdp BET
Dudng cong hap phy vd gidi hap phy ciJa mlu Nano-NaY (a) vd Micro-NaY (b) theo phuang phdp BET dugc trinh bdy tren hinh 5. Tir day cho thay r5 dudng cong hap phy vd gidi hap phy ciia mdu Micro- NaY cd dgng I theo BET [10], hau nhu khdng cd vong tre, dde trung eho vgt lipu vi mao qudn ngay tai dp suat rieng phan rat thap. Trong khi dd, dudng cong hap phy vd gidi hap phy eua mau Nano-NaY xuat hi?n vdng tri bdt dau tgi p/po = 0,55 thupe dgng 111 [11], dupe gidi thich Id do cd sy ngung ty phan tir nita Irong mao qudn trung binh. Vdi mau Nano- NaY, mao qudn trung binh chi cd thi dugc hlnh thanh tir phan thi tich rdng giiia cae hgt tinh the cd kich Ihudc nanomet.
V, cm'/g -1 350 - 300 - 250 - 200 - 150 -
100 - 50 -
e Hip ptig
• GiSi h^D pfiu
i'W
yy%f -""•"^
- -
P/Po
Hlnh 5: Gian dd hap phu - gidi hap phy ciia mau Nano-NaY (a) dugc tong hgp tir cao lanh va Micro-NaY Phap (b) dugc tong hgp tir hda chat
tinh khiet
Tu hinh 5 ciing ghi nhan, ed hai mau deu cho the tich hap phu cao ngay tai gia tri p/po = 0, chirng td hai mau nay cd dien tich be mat rat cao va xap xi nhau (bdng 565 vd 579 mVg - xem bang 1).
Bdng T. Kit qua so sanh ddc trung vat lieu Nano-NaY dugc tdng hgp tir cao lanh va Micro-NaY Phap dugc tdng hgp tir hda chdt tinh khiet
MSu Nano-NaY Micro-NaY
Tong be mat rieng,
m'/g 565
—
Be mat ngoai, m'/g
102
--
Phiin bo 16 xop, nm 0,81; 12,0
- 8 1
Kich thuoc hat tinh the, nm Theo
XRD 19 400
Theo SEM 165 620
Theo TEM 22
Tong the tich 16 x6p,
cm^/g 0,332 0,343
The tich micro,
cm^/g 0,190 0,234
TCHH, T. 50(3), 2012
Tren hinh 6, phin b6 l6 x6p ciia c4c mlu Nano- NaY (a) vii Micro-NaY (b) dupe tinh tota IrSn co sd phuong phdp ly thuyet him [12], C4 2 mSu d^u chtta h? mao qudn chinh v6i kich thudc khodng 0,81 mn.
Tuy nhien. 4 mSu Nano-NaY c6n xu4l hi§n mao quin rpng hon d vilng = 12 nm 14 nguyfin nhSn gSy ra v6ng tre dii dupe chi ra tren hlnh 5.
0 5 10 20 110 120 130 W, A
Tif Ngpc Don vd cong sif K& qui phdn tich /-plot xic djnh dupe b6 m}t riSng cia mlu Nano-NaY thSp hon so v6i mau Micro-NaY nhung 1^1 c6 be m$t ngoai ldn hom nhieu (bing 102 so vAi 37 m'/g). RS ring, sir ting b^ mjt ngoii cOa Nano-NaY so vdi Micro-NaY li do sir giim kich thudc h(il linh thi zeolit NaY tir micromet xu6ng nanomet (xem bing 1).
dV/dW. cm*/o/nm
" 0 81nm
110 120 130 W. A Hinh 6: Phan bo lo xop ctia mlu Nano-NaY (a) dupe tong hpp tir cao lanh v i
Micro-NaY Phip (b) dupe tong hpp tir hda chat tinh khict 4. KET LUAN
1. Lan dau tien, tir cao lanh A Ludi Vi§t Nam da tong hpp thanh cong vit lieu zeolit NaY c6 kich thudc nano trong su c6 mit ctia chat tao cau true hiru CO DNy.
2. BSng cae phuong phip XRD. IR, SEM, TEM va BET da chirng to, vat lieu nano-zeolit NaY dupe tong hpp CO dp tinh the cao, be mit rieng 565 m^/g, trong do be mat ngoii dat tdi 102 m^/g, tinh the zeolit NaY tao thanh co kich thudc khoang 22 nm.
3. Vat lieu nano-zeolit NaY dupe tong hpp cd chua ddng thdi kich thudc mao quin nhd (0,81 nm) va mao quan trung binh (12 nm). khac vdi vit lieu zeolit NaY thdng thuemg chi chua kich thudc mao quin nhd.
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Lien he: Ta Ng^c Don Vien Ky thuit Hoa hpc Tnrdng Dai hpc Bich khoa Ha Ngi So 1 Dai C6 Viet. Hai Ba Trung. Hi Npi Email. tndon@mail,hut edu.vn.
