TAP CHi CONG THIfONt
NGHIEN Clfu TONG HdP
VAT LIEU KHUNG HLfU COf KIM LOAI KEM TEREPHTALAT VA DONG (II) TEREPHTALAT TlJ AXIT TEREPHTALIC
TAI CHE Tl/ NHl/A PET
• VO QUANG MAI - NGUYEN NH J HUNG - QUACH N G U Y I N K H A N H NGUYEN - PHAM TH! THANH H J C J N G
TOM TAT:
Hien nay d nhidm rac thai nhffa dang la van de nan gidi dd'i vdi mdi trffdng, trong do so' Iffdng nhffa PET (polyethylene terephthalate) phd' thai ngay mdt tang nhanh chdng, ehid'm 30%
tong Iffdng PET tieu thu, nhffng chi cd mpt phan nhd dffdc tai che' (trong nam 2016 la 7%). D^
gdp phan bao v6 mdi trffdng cung nhff tao ra vat lieu cd nhieu ffng dung, trong nghien ciiu nay chung tdi tai sff diang nhffa PET dd' t6ng hdp axit terephtalic (TPA), tff dd diing de che' tao vdt lieu khung hffu cd kim loai MOF-Zn va MOF-Cu. Cac MOF nay dffdc t6ng hdp bang phffdng phap nhiet dung mdi. Trong bai bao nay, chung tdi tdng hdp cac MOF vdi khung hffu cd TPA dffdc dieu ch6' tff nhffa phe thai PET, cac khung kim loai la Cu (II) va Zn (II). Cac phep phan tich ca'u true v|t lieu dffdc thffc hidn bang gidn dd tia X (XRD, DS-Advance Bruker, Dffc), phd hdng ngoai bien ddi Fourier (FT-IR, BIO-RAD FTS-3000, Nhat Ban), ffinh thai be mat dffdc phSn tich bang hien vi dien t^ truyen qua (TEM, JEOL 1010, Hitachi, Nhat Ban) va hien vi dien tff qudt (SEM, S4800, Hitachi, Nhat Ban).
Tuf khoa: Khung cd kim hiJM cd, chat diai nhffa PET, TPA, che tao.
I. Gidi thieu
vat lieu khung hffu cd kim loai (metal organic frameworks, MOFs) la loai vat lieu dffdc cac nha khoa hoc tren the' gidi quan tam nghien cffu vao thap nien 90 cua the ki XX. Ke tff dd de'n nay, so' cdng trlnh nghien cffu ve loai vat lieu nay ngay mot tang len mdt each nhanh chdng [ 1 ]. Vat lieu MOFs dffdc ca'u true tff cac ion hoac cac cum ion kim loai vdi cac cau ndi hffu cd trong khdng gian 3 chieu, la loai vSl lieu xd'p vffa cd mao quan trung binh vffa cd vi mao quan. Tuy thudc vao phffdng phap tong hdp.
loai ion kim loai hoac cau ndi hffu cd cd the thu
dffdc cac loai vat lieu MOFs khac nhau nhff MOF-5, MOF-77, MlL-101, MIL-125, MIL-47, MIL-53 cd pho'i tff hffu cd la axit da chffc va mpt kim loai chuyen tiep hda tri II, III vi du nhff Cu, Zn.
MOFs cd dien tich be mat va th^ tich mao quan ra't ldn (2000-6000 m^/g; 1-2 mVg) [2][3][4][5], he thdng khung mang 3 chieu, ca'u tnic hinh hoc da dang, cd dem nang ffng dung trong nhieu ITnh vffc lffu trff khi, cd nhieu ffng diing lam xuc tac cho cac phan ffng hffu cd. Trong cac nghien cffu hien nay, sff dung ngudn terephtalat tff axit terephtalic (TPA), TPA dffdc tai tao tff nhffa PET, day la mot
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uuiia nam. inub rnHM
P°Jyi"f dffdc sff dung pho bie'n lam chai Ig chffa chat long nhff nffdc tinh khie't, nffdc cd ga, nffdc ngot, nffdc tffdng,... Vdi Iffdng vd chai PET ngay cang tang, theo sdheu nam 2009 toan the gidi da su:
dung 15,5 tridu ta'n PET va den nam 2017 dat den 20 trieu tl'n. Viec PET ngay cdng dffdc sff dung nhieu nhff vay, thfim vao dd PET la loai nhffa khong bi giam cap trong dieu kidn tff nhien va cho tdi nay chffa cd cdng bd' nao ve vi sinh cd the phan huy dffdc PET, ddng nghTa vdi Iffdng thai hang nam tang len ra't nhanh gay anh hffdng nghiem trgng de'n mdi trffdng [6]. Do do, nghien cffu tff nhffa PET phe' thai lam nguon tdng hdp MOFs mang y nghia rat ldn ve mdi trffdng cung nhff khoa hoc.
II. Thi^c nghiem / . Bieu che'TPA tin PET
La'y l,5g NaOH cho vao 2g nhffa PET d\i(ic cat nho (6 mm x 6 mm) cho vao binh ndn chffa 10ml dung dich etylen glycol va trdn deu. Dffa binh vao Id vi sdng d cdng sua't nha't dinh trong thdi gian xac dinh. La'y mlu de ngudi d nhiet do phdng rdi them ti^p 2Qml nffdc ca't va khua'y deu. Sau dd tien hanh loc rffa mlu bang NaOH va H2SO4.
2. Tdng hap vat li$u khung hUu cd kim loai Zn-TPA
Mlu MOFs dffdc tdng hdp theo phffdng phap thuy nhidt. Quy trinh tong hdp dffdc thffc hien: hdn hdp l,782g Zn(N03)2.6H20,0,249g axit terephtalic (thu dffdc tff PET thai, sau khi da tinh che), 150ml N,N dimetylfomamit dffdc khua'y tan trong 15 phut, sau dd cho hdn hdp vao cdc 250nil va dffdc gia nhiet den lOO^C trong 24h d dieu kien tinh. San pham thu dffdc dang tinh the vang nhat. San pham tao thanh dffdc ngam trong lOml dung mdi N,N dimetylfomamit trong 3 ngay va mdi ngay thay dung moi 2 lan, sau do ta cung tie'n hanh tffdng tff vdi dung mdi CH2CI2. Cac qua trinh ngam va rffa san pham trdn dffdc thffc hien d nhiet do phdng.
3. Tdng hap vat li^u khung hHu cd kim lotii Cu-TPA
Mlu MOFs dffdc tdng hdp theo phffdng phap thuy nhiet. Quy trinh tong hdp dffdc thffc hien:
hdn hdp l,668g Cu(N03)2.5H20, 0,249g axit terephtalic (thu dffdc tff PET thai, sau khi da tinh che), 150ml N,N dimetylfomamit dffdc khua'y tan trong 15 phut, sau dd cho hdn hdp vao cd'c 250ml va dffdc gia nhiet dd'n 100"C trong 24h d dieu kien tTnh. San pha'm thu dffdc cd dang chat ran mau xanh. San pham tao thanh dffdc ngdm trong 10ml dung r.idi N,N dimetylfomamit d-ong 3 ngay va
mdi ngay thay dung mdi 2 lan, sau dd ta cung den hanh tffdng tff vdi dung moi CH^Cl,. Cac qua trinh ngam va rffa san pham tren dffdc thffc hien d nhiet dp phdng.
i n . Kg't qua va thao lu§n 1. Gidn do nhiiu xa tia X (XRD)
De nghien cffu ca'u tnic tinh thd' cua vat lidu, mau nhilu xa tia X (XRD) da dffdc thffc hien tai nhiet do phdng. Cac ke't qua dffdc hi^n thi trong Hinh 1.
Hinh 1: Cac mdu XRD cua TPA, MOF Cu-TPA va Zn-TPA
,j'
J L
10 20 30 40 50 60
20 (degree)
Nhieu xa tia X cho TPA dffdc xac dinh cac peak dac trffng d 20 = 17.4°, 24.77", 27.98", Quan sat dinh nhieu xa ra't phu hdp vdi cac tai Heu xac dinh stf hinh thanh TPA [7]. Khdng tha'y cd dinh nhieu xa thff cap nao lien quan de'n cac pha hoac tap cha't khac dffdc phat hien. Dinh nhiiu xa cua mau nay cd cffdng do cao, sac, nhgn; dien hinh la dinh chinh d vitri 17,4", chffng to cho viec che'tao thanh cdng vat lieu TPA vdi dp tinh khie't cao.
Nhilu xa tia X cua MOF-Zn the hien cac dinh nhilu xa d khoang 8.89", 12.09", 15.06" tffdng ffng vdi cac mat mang dac trffng (220), (400) va (420), tffdng ffng. Cac dinh nhieu xa cua mau MOF-Zn phu hdp vdi mlu XRD dffdc cdng bd' cho MOF- Zn [4]. Cac dinh cd dd phan giai td't vdi do sac net va cffdng do cao cho tha'y do ke't tinh cao cua MOF-Zn.
Nhidu xa tia X cua MOF-Cu thd' hidn cac dmh nhieu xa d khoang 10.19", i7.4«, 24,77" tffdng tfng vdi cac nhidu xa dac Q-ffng (220), (440), (444). Cac dinh chinh cua mlu MOF-Cu phu hdp vdi mlu XRD dffdc cdng bd cho MOF-Cu [8].
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TJjiP CHi CONG THirHNE
2. Kinh hien vi di^n tic quet (SEM) Hinti 2: Anh SEM cua vat lieu
Anh SEM cua MOF-Zn cho tha'y cac hat cd hinh dang khac nhau va kich thffdc tinh the khdng ddng deu (hat trdn, hat thon dai, khdng deu...), khoang each giffa cac hat cung khdng d^u, cdn anh SEM cua MOF-Cu cho tha'y sff phan bd' kich thffdc hat hep. Hau he't cac phin tff dinh ldn nhau.
3. Kinh hien vi di^n tiC truyen qua (TEM) Hinh 3: Anh TEM cua vat lieu MOF-Cu va MOF-
Anh TEM cua vat lieu MOF-Cu (Hinh 3a) cho tha'y hinh anh vat lieu la hinh lap phffdng nhffng cd mot so manh tinh thi dinh xung quanh. Cdn d mlu MOF-Zn cho tha'y vat lieu la nhffng khd'i lap phffdng chdng len nhau (Hinh 3b).
4. Phdn tich ph6 hong ngoai (FT-IR) Trong phd' FT-IR cua TPA, dai dac trffng d 878
cm ' va 787 cm-I la dao ddng bie'n dang ngoai mat phang cua lien ke^t C-H trong CioH,o04, cdc dinh d 1510 c m ' va 1578 cm-1 la cac dao ddng cua lien ke't C=C trong C10H10O4, Cac dai d 1689 c m ' va 1423 cm ' lan lffdt la lien ke't C=0 vd C- O cua axit cacboxylic, ddi manh d 1283 cm-1 la dao ddng hda tri cua lien ke't C-OH dai dien cho ddi dac trirtig cua TPA. (Hinh 4).
Trong phd FT- IR cua MOF'Zn, Cac dai d 1581 cm-1 va 1390 cm- 1 la cac dao dgng hda tri dd'i xffng va bd't dd'i xffng cua lien ke't C-0 trongC|oHio04. 3 dai manh quan sdt dffdc d 830 cm', 748 cm-1 va 652 c m ' dffdc ddc trffng cho dao dpng bie'n dang ngoai mat phdng cua lidn kd't C-H trong vdng benzen. Ddi d 523 cm' ' la dao ddng hda tri dac trffng cua Zn-0. Kd't qua da xac nhan rang cac dac tinh cua ca'u true MOF- Zn dffdc tdng hdp tffdng tff MOF-Zn tidu chuan, cho tha'y sff thanh cdng cua vat lieu MOF-Zn.
Trong phd FT-IR cua MOF-Cu, dai hap thu d sd'sdng 1585 era"' dac tnftig cho dao ddng cua lien
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nuH nut - i\im NGHE THDC PHAM
Hinh 4: PhS hdng ngoai cua MOF-Zn, MOF-Cu va TPA
• " " ' ^
-TPA MOF-Cu MOF-Zn
2CO0 A (cm-')
ka'tC=0. Dai ha'p thud so sdng 1463 cm-' va 1394 cml dac trffng cho dao ddng hda trj ddi xtfng va bat dd'i xffng cua nhdm cacboxylic cua 1,4-ben- zen dicacboxylic lidn ke't phd'i tri vdi kim loai trung tam. Dai hap thu d so' sdng 618 cm"' dac trffng cho dao dgng hda tri lien kd't Cu-0. Dai ha'p thudsdsdng735cm-'va 1109 cm-' dac trffng cho dao dong Hdn kd't C-H cua vdng benzen.
IV. Kd't luan
Trong nghien cffu nay, chung tdi tdng hdp dffdc vat lieu MOF-Zn va MOF-Cu bang phffdng phap nhidt dung mdi tff axit terephtalic dieu che' tff nhffa phd' thai PET. Cdc dac trffng hda ly cua cac vat lieu da dffdc kiem tra va ddnh gia bang nhilu xa tia X (XRD), phd hdng ngoai (FT-IR) cho tha'y sff thanh cdng ve che' tao, cac dac tinh ddn tinh thd' dffdc thi hien •
L^i cdm <Jn:
Cong trinh duac hodn thdnh vdi stf hd tr^ cua de tdi cd'p ca sd TrUcfng Dai hoc Sdi Gon md s
TAI LIEU THAM KHAO:
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Ngay nh§n bai: 5/6/2019
N-^ay phan bidn danh gia va suTa chifa: 15/6/2019 [Sfgay chap nh$n dang bai: 25/6/2019
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TAP CHi CDNG THIftiNG
Thong lin ldc gid:
PGS. TS. VO QUANG MAI NGUYEN NHIJ HUNG
TS. QUACH NGUYEN KHANH NGUYEN ThS. PHAM THI THANH HlfCiNG Trrfdng Dai hoc Sai Gon
A STUDY ON FABRICATION OF METAL ORGANIC FRAMEWORKS OF ZN/CU (U) TEREPHTHALATE
FROM WASTED PET PLASTICS
• Assoc. Prof, VO QUANG MAI
• Master student. NGUYEN NHU HUNG
• Ptl.D. QUACH NGUYEN KHANH NGUYEN
• Master. PHAM THI THANH HUONG Saigon University
ABSTRACT:
Nowadays, the plastic pollution is a raising problem worldwide. In which, the volume of wasted polyethylene terephthalate (PET), accounts for 30% of total used PET, is increasing rapidly. In order to protect the environment and create a multipurpose material, in this study, the TPA was synthesized by the PET in order to fabricate jMOF-Zn and MOF-Cu. The MOF-Zn and MOF-Cu was fabricated by using the solvothermal method. The crystal structure and morphological properties of these MOF were investigated by X-ray diffraction (XRD), Fourier Transform Infrared (FT-IR) and microscopy techniques such as transmission electron (TEM) and scanning electron (SEM) microscopies. XRD pattems of synthesized samples showed the success of MOF fabrication. FT-IR showed the bonding of Cu-O and Zn-0. TEM micrographs indicated that shapes of MOF-Zn and MOF-Cu are homogeneous.
Keywords: Metal organic framework (MOF), wasted PET, TPA, fabrication.
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