TAP CHI HOA HOC T. 51(6)780-785 THANG 12 NAM 2013
TONG Hap, DAC TRU'NG VA U'NG DUNG VAT LIEU NANO-ZEOLIT NaX
TU' CAO L A N H
V - DANH GIA TINH C H A T H A P PHU ASEN VA H A P PHU CUMEN CClA VAT LIEU NANO-ZEOLIT NaX
Ha Thi Lan Anh', Ta Nggc Bon^*
'Truang Cao dang Cdng nghiep Thirc phdm Viet Tri 'Truang Dgi hoc Bdch khoa Hd Ndi
Din Toa soan 03-11-2012
Abstract
Nano-zeolite NaX was exchanged with cation Fe^' to remove arsenic in solution and adsorb cumene in dynamic mode. The obtained results showed that 0 070 g nano-zeolite NaX exchanged with cation Fe^* can be used to treat 1 I of water to reduce arsenic concentration from 0.5 mg/1 to 0.001 mg/1, it meets the requirement of TCVN 4945-2005 and WHO for drinking water. Synthesized nano-zeolite NaX is stable and it can adsorb and desorb cumene quickly, and the adsorpnon capacity is higher than standard NaX zeolite.
Keywords Nanozeolite, ?eohtc, kaolin, adsorption
l.DATVANDE
Muc ticu ciia nghien cuu irng dung vat lieu ndi chung va vat lieu nano-zeolit NaX ndi rieng la xem xet khai thac cac lgi the ve cau tnic va tinh chat ciia cluing. Ddi vdi nano-zeolit NaX, lgi the cua vat lieu nay chinh la kha nang hap phu va trao ddi cation do day la vat lieu vi mao quan, cd do xdp cao, chira nhieu tir dicn AIO4' va nhat la cd kich thudc hat nam trong thang nanomet nen xuat hien cac hieu img be mat lam cho kha nang trao ddi cation va hap phu tdt han so vdi cac vat lieu kich thudc micomet thdng thudng
Vi vay, trong bao cao nay chimg ldi frinh bay ket qua su dung nano-zeolit NaX da dugc tdng hgp theo [ 1J va nano-zeoht NaX da trao ddi mdt phan vdi Fe''"' de hap phu asen trong nudc. Ddng thdi, vat lieu nano-zeoht NaX cung dugc su dung de hdp phu cumen d trang thai ddng.
2 THUC NGHIEM
2.1. Nghien ciru kha nang hap phu asen 2.1.1. Vdt li<}u hdpphuvd dung dich gdc
Fe * (Nano-NaXFe) va zeolit kich thudc micro (Micro-NaX) dugc tdng hgp theo [2] de so sanh Mau Nano-NaXFe dugc tao thanh sau khi trao doi 2,85g Nano-NaX frong 250 ml dung djch NH4Fe(S04)2.12H20.
- Dung dich gdc chira asen dugc pha che tir AsiOj vdi ndng dd 0,5 mg/1.
2.1.2. Ddnh gid khd ndng hdp phu asen 2.1.2.1. So sdnh kha ndng hdp phu asen cua cdc mdu Micro-NaX, Nano-NaX vd Nano-NaXFe
Can 0,10 g mdi mau Nano-NaXl, Nano-NaXFe va Micro-NaX rdi them vao 1 lit dung djch asen 0,5 mg/1 va dieu chinh ve mdi trudng pH = 7. Cac mau dugc lac manh fren may lac SHEL-LAB frong 15 phiit d nhiet dp 25''C, dk yen 15 phiit. Kit thiic qua trinh xir ly, chat ran dugc Igc bd, thu lay dung dich lgc va djnh mirc bang nudc cdt din 500 ml. Nong dp asen frong dung djch trudc va sau qua trinh xu ly dugc xac djnh tren may quang phd hap thu nguyen tir AA6601F (Shimadzu, Nhal Ban), tir dd xac djnh dugc % asen da bi hap phu.
2.1.2.2. Ddnh gid khd nang hdp phu asen cita Nano- NaXFe
- Vat lieu sir dung la nano-zeolit NaX (Nano- Quy trinh thuc nghiem dugc tien hanh tucmg tir NaX). nano-zeolit NaX da frao doi mgt phan vdi nhu phan thuc nghiem 2.1.2.1 vdi 7 mau, trong do
TCHH, T. 51(6), 2013
Iugng Nano-NaXFe thay doi bang 0,01; 0,03; 0,05;
0.07; 0,10; 0,15 va 0,20 g.
2.1.2.3. Ddnh gid khd ndng hdp phu asen cua Nano- NaXFe trong dung dich cd mat chdl oxi hda
Dimg nudc gia ven oxi boa As(III) thanh As(V) va khao sat su hdp phu As(V) ciia Nano-NaXFe.
Quy trinh thuc nghiem dugc tien hanh tuong tu nhu phan thuc nghiem 2.1.2.1 vdi 4 miu cd chiia sin mgl lugng nudc gia ven, lugng Nano-NaXFe thay ddi bang 0,03; 0,05; 0,07 va 0,10 g.
2.2. Nghien cihi kha nang hap phu dong cumen Phuong phap hap phu dgng cumen dugc tiin hanh tren he may sdc ky may GC-14B (Shimadzu, Nhat Ban). Mau dugc boat hda d nhiet do 300 °C sau do ha nhiet dp xudng 40 °C dl tien hanh hdp phu.
Khao sat anh hudng ciia thdi gian hoat hda miu den kha nang hap phu vdi cac khoang thdi gian hoat hoa la 1, 2 va 3 gid. Tien hanh chay bypass kiem tra ndng do cumen trong ddng khi trudc hdp phu khi tdc do ddng khi dn dinh. Qua frinh nha hdp phu tai 300
°C Do ben hap phu ciia mau ciing dugc khao sat lien tiep nhieu ian ddi vdi cimg mdt mau trong cac dieu kien lugng tu,
3. KET QUA VA T H A O LUAN
3.1. Ket qua nghien ciru kha nang hap phu asen 3.1 1 Khd ndng hdp phu asen cita cdc mdu Micro- NaX. Nano-NaX vd Nano-NaXFe
Asen frong nudc tdn tai d hai dang boa tri la As(lll) va As(V), trong dd As(lll) thudng tdn tai trong nudc nhieu hon so vdi dang As(V) [3]. Ddi vdi sat, trong nudc lai chii yeu tdn tai d dang Fe"'. nen ta can mgt chat oxi hoa de tach sal ra dudi dang Fe^'.
Ban than Fe''* la mpt tac nhan cdng kit va hap phu kha lot nhieu ion trong dd cd asenit va asenat [4].
Tg Ngoc Ddn vd cdng sir Nhu vay phuang phap xii Iy As dua fren kha nang tao thanh hgp chat it tan ciia As(V) nhu FeAs04, AIASO4 va de lach asen ra khdi nudc, frudc tien phai chuyen nd ve dang As(V), sau dd sdt se cdng kit vdi As(V).
Tir dd, chiing tdi sir dung Nano-NaX da frao doi mdt phan sat de hap phu asen Fe(III) frong nano- zeoht chii yeu nam fren be mat vat lieu se ket tua vdi asen d dang FeAs04 idng xudng. Ngoai ra, Fe(III) bu frir dien tich khung mang nano-zeolit do da frao ddi mdt phan vdi Na' va Na*cdn lai trong khung mang nano-zeolit cd the tham gia trao ddi vdi asen. Vi vay.
Nano-NaXFe vira cd tac dung hap phu asen vira cd lac_ dung keo tu - frg lang, keo ket tiia vdi asen xudng nhanh. Phuong phap xu ly asen bdng Nano- NaXFe la sir ket hgp giira phuong phap hdp phu - trao ddi ion - keo tu Do vay hieu sual xir ly cd thi se cao hon so vdi cac phuong phap khac da bill
Bang 1 trinh bay kel qua hap phu asen cac mdu Micro-NaX, Nano-NaX va Nano-NaXFe trong dung dich ban ddu cd nong dp As(III) bdng 0,5 mg/1; pH = 7; thdi gian hdp phu 1 5 phut; nhiet do 25 "C.
_ Tir ket qua thuc nghiem ibu dugc d bang 1 cho thay, kha nang hap phu asen ciia Nano-NaX cao hon so vdi mau Micro-NaX va vat lieu Nano-NaX sau khi trao ddi mdt phan vdi sat de tach loai asen ra khoi nudc cho hieu qua cao hon nhieu.
Kha nang hap phu khac nhau giua Nano-NaX va Nano-NaXFe dugc chirng minh qua dai lugng dung lugng hap phu chiing, tuang irng vdi % asen hi hap phu trong ciing dieu kien khao sat la 80,8 va 99,8%.
Ket qua nay cho phep khang dinh, khi nano-zeolit NaX da trao ddi mgt phan sat, qua trinh hap phu dugc thuc hien khdng chi theo co che hap phu- trao doi ion binh thudng ma cdn cd the xay ra theo phuang phap hap phu-keo tu do su xuat hien sat tren be mat zeolit. Ket qua nay phii hap vdi ket qua da bao cao frong tai lieu [4] khi xir ly asen trong nudc bang bentonit va bentonit da hoat hoa phii sdt,
Tir kel qua nay, Nano-NaXFe dugc su dung de xir ly asen trong nudc nham tim ra dieu kien thich hgp de cd the iing dung trong thirc tien.
Bdng 1: Kha nang hap phu As(ni) ciia Micro-NaX, Nano-NaX va Nano-NaXFe
STT 1 2 3
Chat hap phu Micro-NaX Nano-NaX Nano-NaXFe
Luong vat lieu hap phu, g
0,10 0,10 0,10
Nong do As sau hiip phu, mg/I
0,120 0,096 0,001
Dung lugng hap phu, mgAs/g
3,8 4,04 4,99
% As bi hap phu 76,0 80,8 99,8 3 L2. Anh huang ciia hdm lugTig Nano-NaXFe din
qud trinh hap phu As(lll)
D I khao sat anh hudng ciia ham lugng Nano-
NaXFe den qua trinh hap phy As(lll), nong dg As(lll) ban dau (trudc khi trao ddi) dugc chpn bang 0,5 mg/I. Day ia nongdg As(llI)cao gap 10 ian theo
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QCVN 24:2009/BTNMT cho phep ddi vdi nudc thai cdng nghiep khi dd vao cac khu vuc nudc dimg cho muc dich sinh boat (<0,05 mg/1), cao gap 50 lari tieu chuan an toan cho phep ciia Td chiic Y te the gidi WHO (<0,01 mg/1). Ndng dd nay cung thudng
Tdng hap, dgc tnmg va ung dung, phdn V.
tuong duang vdi ndng do asen gay d nhiem tai mgt sd vimg d Viet Nam [5], vay nen, niu nghien ciiu nay thanh cdng thi kha nang irng dung thuc tien sg fro nen kha thi hon. Ket qua thuc nghiem dugc trinh bay frong bang 2.
Bdng 2: Kha nang hap phu As(in) ciia Nano-NaXFe
STT 1 2 3 4 5 6 7
Lugng Nano- NaXFe, g
0,010 0,030 0,050 0.070 0,100 0,150 0,200
Nong do As(lll) sau hSp phu, mg/1
0,243 0,096 0,009 0.001 0,001 0,001 0,001
Dung lirgng hap phu, mgAs/g
25,70 13,47 7,01 5.01 4,99 3,33 2,50
% As bi hap phu, %
51,40 80,80 98,20 99,80 99,80 99,80 99,80 Ket qua thu dugc trong bang 2 cho thay, trong
nhirng dieu kien hap phu nhu nhau, khi tang lugng Nano-NaXFe thi dung lupng hap phu giam dan cimg vdi sir giam dan ndng dp As(lll) do dugc sau hap phu bang phuong phap AAS. Tuy nhien, tir lupng Nano-NaXFe bang 0,070 g trd di thi nong dp As(Il!) sau hap phu va % As bj hap phu khong thay ddi, tuong irng bang 0,001 mg/1 va 99,80 %. Ket qua nay chung td tir gia tri 0,070 g Nano-NaXFe frd di, qua trinh hap phu As(IlI) da dat trang thai can bang, hay ndi diing han la trong dieu kien thuc nghiem da neu, lugng Nano-NaXFe bang 0,070 g la luong tdi thieu de CO the hap phu As(lII) tir ndng dp 0,5 mg/1 xudng cdn ndng dp 0,001 mg/1. Day chi'nh la lugng Nano- NaXFe thich hgp de xii ly As(lII) dat thap hon tieu
chuan ciia WHO va thap han nhieu so vdi QCVN 24:2009/BTNMT [6].
5.7.3. Anh hudng ciia hdm hrang Nano-NaXFe den qud trinh hdp phu As(V)
Nhu da biet, asen thudng tdn tai trong nude d dang asenic hoa frj III. Dang nay thudng khd xii ly hon dang asenat hoa fri V [7]. Vi vay, chung loi su dung chat oxi hoa cho phep frong qua frinh xir ly nudc la nudc gia ven de chuyen As(lll) Ien As(V) trudc khi xu Iy. M^t khac, nudc gia ven la chat cd klia nang dua As(lII) Ien As(V) cd hieu qua hon ca, khdng gay d nhiem thu cap phan du thira de bj phan huy [4, 8]. Ket qua thirc nghieni dugc trinh bay frong bang 3.
Bang 3: Kha nang hap phu As(V) ciia Nano-NaXFe
STT 1 2 3 4 5
Lugiig Nano-NaXFe, g 0,030 0,050 0,070 0,100 0,150
Nong do As(V) sau hap phu, mg/1
0,008 0.001 0,001 0,001 0,001
Dung lugng hap phu, mgAs/g 9,84 8,62 7,23 4,99 3,33
% As b| hap phu,
%
98,40 99.80 99,80 99,80 99,80 Qua so lieu trong bang 3 cho thay, mau Nano-
NaXFe hap phu As(V) dat gia tri bao hda iing vdi ham luong 0.050 g/1 va lugng As(V) bi hdp phu dat 99,8%. tuong duong vdi khi sii dung 0,070 g Nano- NaXFe de hap phu As(III) nhu da trinh bay frong bang 2. Dieu nay chirng Id, dl tang hieu sudl xir ly va xu ly triet de asen thi nen dua As(III) Ien As(V) bdi qua trinh oxi hoa bang nudc gia ven.
Tdm lai, vdi ndng do As ban dau la 0,5 mg/1, de xu ly 1 m^ nudc dat tdi gidi han cho phep ciia WHO (0,01 mg/1) thi cdn 50 g Nano-NaXFe cimg vdi vi?c sii dung chat oxi hoa la nudc gia ven hoac 70 g Nano-NaXFe xii ly As(III). Kel qua nay da giam dugc 4 ldn lugng vat lieu su dung so vdi bentonit da hoat hoa va phu sat [4] ma van cho hieu qua sir dung tot.
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3.2. Ket qua hap phu cumen cua vat lieu nano- zeolit NaX
3.2.1. Duong chudn cumen
Tir cac so lieu thuc nghiem, dudng chudn cumen the hien mdi quan he giira ndng do cumen va dien tich pic do dugc tir may sac ki da dugc xie djnh.
Bang phuong phap hdi quy tuyIn tinh, phuong trinh dudng chuan cumen tinh toan dugc cd dang y = 3,385><10" X. Tir dd cd the tinh dugc ndng do cumen (ppm) trong ddng khi tir dien tich pic do dugc tir
Tg Nggc Ddn vd cdng su may sac ki.
3.2.2. Khdo sdt thdi gian hogt hda mdu din kha ndng hdp phu
Mau trudc khi cho hdp phu dugc boat hda d nhiet do 300°C nham giai phdng cac chat da hap phu tren mau, tao dieu kien tdt nhat cho qua trinh hap phu.
Thdi gian boat hda mau dugc khao sat lan lugt frong 1, 2 va 3 gid. Dudng cong hap phu \a nha hap phu ciia mau nano-zeolit NaX tucmg ung vdi cac khoang thdi gian hoal hoa tren dugc the hien frong hinh 1.
NAng do c u m e n , ppm 6 000
Oiro'ng c o n g h i p p h u 5.000 ^ - J 4 000 • 3.000
2.000 1.000
• Hoat hoa 2h
• Hoat h6a 3h
• Hoat hoa 1 h
Nong do cumen, ppm 25 000
10 000 - 5,000 •
DiFO'ng cong nhd h^p phu
• Hoat hoa 2h - • Hogt h6a 3h
— • Hogt hoa 1h
Thdi-i g i a n hdp p h u , phut ThOT gian nha h3p p h u , phut
Hmh I: Dudng cong hap phu va nha hap phu cumen ctia Nano-NaX d cac thdi gian hoat hda khac nhau
Tir hinh 1 nhan thay, khi tang thdi gian hoat hda thi kha nang hap phu va lugng hap phu tang Ien. Vdi thdi gian hoat hda mau la 1 gid thi kha nang hap phu thap hon so vdi boat hda trong thdi gian 2 va 3 gid, Nguyen nhan la do khi hoat hda mau trong 1 gid, cac chdt da hap phu tren mau chua dugc giai phdng hoan toan va lam giam kha nang hap phu ciia mau. Cdn khi hoat hda lau hon thi dii thdi gian de dudi triet de hon cac chat bj hap phu sau trong cac mao quan.
Kha nang hap phu ciia mau cd thdi gian hoal hda 3 gid cao hon mau 2 gid nhung khdng nhieu, dudng cong hap phu - nha hap phu rat sal nhau.Nhu vay vol thdi gian hoal hda 2 gid, mau da du dicu kien de hap phg tdt nhat.
3.2.3. So sdnh khd ndng hdp phu cua mdu Nano- NaX vd Micro-NaX
Hai mau Nano-NaX va Micro-NaX dugc hoat hda d 300°C frong 2 gid, sau dd cho hap phu dgng cumen. Tir so lieu thuc nghiem, cac dudng cong hap phy va nha hdp phy dugc trinh bay frong hinh 2.
Ket qua nhan dugc frong hinh 2 diu khdng djnh ca hai miu d&u hap phy cumen tdt, tuy nhien cd su
khac nhau dang ke ve kha nang hap phu va nha hap phu cumen. Q giai doan dau (15 phiit dau) thi dd thi hap phu cua mau Nano-NaX thap hon va cd do ddc nho han so vdi dd thi ciia mau Micro-NaX thdng thudng. Con d giai doan tiep theo cho thay mau Nano-NaX cd kha nang hap phu va nha hap phu nhanh hon, dung lugng hap phu cao hon so vdi Micro-NaX. Den phiit thir 40 thi mau Micro-NaX gan nhu bao hda cdn mau Nano-NaX chi can den phiit thir 35.
Giai doan dau hap phu thi ca mau Micro-NaX va mau Nano-NaX deu hap phu nhieu cumen lam giam manh ndng dp ciia cumen trong ddng ra, nhung mau Nano-NaX lam giam sau ban. Cd the giai thich nhu sau: ca hai vat lieu nay deu cd dp xdp Idn nen hap phu manh cumen, nhung mau Nano-NaX xdp hon nen hap phu nhieu han. Dd la do vat lieu Nano-NaX co kich thudc nhd hon nen dien tich be mat ldn hon, sd lugng mao quan nhieu hon nen the tich hap phu ldn hon, dl hdp phu hem. Ngoai ra, Nano-NaX cdn co cac mao quan thir cap nam d viing mao quan trung binh, cac mao quan nay cd kich thudc Idn han nhicu kich thudc ddng hpc ciia cumen nen hap phu nhanh cumen ddn den lam giam nhanh ndng dd cumen
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6 giai doan sau do miu Nano-NaX cd the tich hap phu ldn hon nen vin hdp phu cumen nhieu hon lam do thj hdp phu van nam d phia dudi. Nhung sau khi cac mao quan thii cdp da dien gdn day thi qua trinh hdp phu phu Ihudc chii yeu vao cac mao quan nhd ban. Cac zeolit thdng thudng cd kich thudc ldn hon nen chieu dai khuech tan trung binh ciia cac mao quan se dai hon do vay qua Irinh khuech tan cac
Tdng hop, ddc tnmg va ung dung, phan V.
phan tu cumen vao sau frong cac mao quan dien ra cham ban, dugc the hien d do ddc dd thj nhd han.
Vdi mau Nano-NaX cd kich thudc hat cd nano nen chieu dai mao quan ngan han cac zeolit thdng thudng (Micro-NaX) vi vay cac phan lir se nhanh dien day mao quan va do ddc ciia do thi se ldn hon va nhanh dat bao hda hon.
O v ^ g cong Mp phu
-» Zeolit NaX
Qu^mg cong nhi hip phu
ThM gian hip phu, ptiul T h ^ gian nhi hap phu, phul
Hmh 2\ Dudng cong hap phu va nha hap phu ciia mau Nano-NaX va Micro-NaX vdi cimg dieu kien hoat hda mau d 300"C frong 2 gid
Con vdi qua trinh nha hap phu cho thay mau Nano-NaX nha hap phu nhieu hon va nhanh hon mau Micro-NaX. Do ddc ciia dd thi nha hap phu rat ldn chirng to qua trinh nha hap phu xay ra nhanh.
Chi sau khoang 12 phiit mau Nano-NaX da gan nhu nha hap phu xong, frong khi mau Micro-NaX can hon 16 phiit. Qua trinh nha hap phu xay ra nhanh la do d nhiet dp cao cac phan lir cumen thoai nhanh ra khdi cac mao quan trung binh. Cdn cac mao quan nho thi vdi mau Nano-NaX do co chieu dai khuech
tan ngan hon nen cung thoat ra nhanh hon so voi Micro-NaX.
3.2.4. Do ben hdp phu cita mdu Nano-NaX
Mau Nano-NaX dugc lien hanh hap phu, nha hap phu nhieu lan de khao sal dp ben hap phu ciia mau. Hinh 3 the hien cac dudng cong hap phu va nha hap phu cua mau d ian hap phu thii 1 so vdi lan hap phu thir 6.
N6ng do cumen (ppm) D i f o n g c o n g hap phu
4,000 3.000 2.000 1,000 0 I
H i p phy lan 1 H i p phy l i n 6
N 6 n g d p c u m e n (ppm) 20,000 18 000 16 000 14 000 12,000 10,000 8 000 6,000 4 000 2.000
DiFO'ng c o n g nha h i p p h u
Nha hap phu l i n 1 li Nha hap phu lan 6
Thfri gian hap p h u (phtit) T h a t g i a n nha h d p p h u (phOt)
Hinh 3: Khao sat dp ben hap phu cua mau Nano-NaX
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Ket qua nhan dugc tu hinh 3 xac nhan, su hdp phu va nha hap phu giiia lan 1 va lan 6 hau nhu khdng thay ddi Cac dudng cong hap phu - nha hap phu gan nhu triing nhau chimg td mau Nano-NaX tdng hgp dugc cd do bin hip phu rdt tdt va on djnh.
Day la tinh chdt quy ciia vat lieu vi dp ben hdp phu cao phan anh kha nang hap phu va kha nang tai sii dung hap phu cao ciia vat lieu Nano-NaX. Khi vat lieu cd kha nang tai sinh va tai sii dung cao thi kha nang ling dung se ldn, hieu qua kinh te mang lai cao hon dan den giam gia thanh san pham. Vdi xu the hien nay la tiet kiem chi phi dau vao ma van dam bao chat lugng de giam gia thanh san pham thi frong tuang lai vat lieu Nano-NaX se dugc ung dung nhieu trong thuc te,
4. KET LUAN
1. Da su dung cac vat lieu zeolit NaX, nano- zeolit NaX va nano-zeolit NaX trao ddi Fe(lll) de xii ly nudc cd nhiem asen. Kit qua thu dugc da chirng td, mau nano-zeolit NaX hap phu tdt ban zeoht NaX, vdi lugng 0,070 g nano-zeolit NaX da frao ddi sdt cd the xir ly I lit dung dich asen cd ndng do 0,5 mg/1 xuong ndng dp 0,001 mg/1 sau 15 phiit lai pH = 7 va 25 °C - thda man QCVN 24:2009/BTNMT va lieu chuan WHO sir dung nudc vdi muc dich sinh boat.
Ngoai ra, de tang hieu sudt xii ly asen thi can oxi hda dua As(lll) Ien As(V) bdng nudc gia ven Khi dy, chi can 0,05 g nano-zeolit NaX da trao ddi sat co the cho ket qua tuong tu.
Tg Nggc Ddn vd cdng su 2. Da khao sat kha nang hap phu ddng cumen cua vat lieu nano-zeoht NaX tdng hgp dugc. Ket qua cho thdy miu nano-zeolit NaX tdng hgp dugc cd kha nang hap phu, khii hap phu cumen nhanh, dung lugng hap phu ldn han so vdi zeolit NaX. Ngoai ra mdu nano-zeolit NaX tdng hgp dugc cdn cd dp bin hap phu tdt.
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Lien hi: Ta Nggc Ddn Vien Ky thuat Hda hgc Trudng Dai hgc Bach khoa Ha Ndi Sd 1 Dai Cd Viet, Hai Ba Trung, Ha Npi Email: don.tangoc(ghusl.edu,vn.
