NGHIEN cufu CHE TAO THAN HOAT TINH TUf TINH

NGHIEN cufu CHE TAO THAN HOAT TINH TUf TINH

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DUNG LAM V A T LIEU HAP THU

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CHU XUAN ANH, TA THj THAO, HO LAN PHl/aNG Khoa Hda hpc, TrUdng DH Khca hpc tu nhiin -

Dai hpe Qude gia Hi NOi

SUMMARY ""^

The magnetic activated carbon particles were synthesized by modifying the activated carbon with iron oxide and cfiaracterized by analyzing the quantitative ofFe(II) and Fe(III) in material. The magnetic field effect in the separation using a magnet was also verified. The equilibrium adsorption isotherm of

crystal violet was investigated and the maximum exchange capacity of the material was also determined.

The magnetic activated carbon particles were suitable for removal of water soluble organic dye.

I. Md DAU

Trong cdng nghigp xQ ty nQdc thdi ndi chung va nude nhQng ldgi nude ngdm cd chQg hdm IQpng cacbon hQu thdi dgt nhuPm not rigng, ngudi ta thudnp sQ dgng cd hda tan cae. Logi thQ hai Id cdc nhga trae ddi cation phQdng phdp ddng tg, tpc hoge oxi hda, hdp thu. Tuy tQ tinh, cd khung cae phdn tQ chQa cac nhdm chQc cd nhign, nhQpc diem Idn nhdt eua cdc vgt ligu hdp thu khd nang tign ke't vdi cdc cation vd bae bpc cdc hgt oxit truyen thd'ng Id thdi gian ddng tg lau, sinh ra lupng chat sdt tQ, dQpc dung dg logi bd cdc cation kim logi ngng thdi Idn. VI vgy, hudng nghien cQu mdi phat trign gdn treng nude [7-8]. Ngoai hai logi kg tren, mdt sd vgt ddy la dQa thgm thdnh phdn mang tfnh ehdt tQ tfnh H^U hd'p thu khdc nhQ ede hgt mO,, chitosan cung vao cgu true vdt tigu. Cac vgt tigu ndy dupe digu chg chu dupc tQ tfnh hda dg tegi bd cdc ien kim logi [9-101.

ygu eo kfch thude nhd, dign tfch be mgt rigng tdn ngn ^ ^ , , ,

sau khi khudy, cae hgt tQ tfnh cc cgm vdi nhau thdnh ''•°"9 ^0 ede vgt tigu hdp thu sdn ed trong tg nhign mgt khd'i sa ldng, tach dg ddno khdi pha Idng. Da sd "^^^ ^d trdu, mun cQa, xd dQa..., than hcgt tfnh ed khd cdc hgt mgng tQ tfnh Id oxit sdt tQ [1-2]. VI vdy, tfnh "g^Q hd'p thu nhigu togi hpp chd't cd vO cd vd hQu cd chdt eua vgt ligu tQ tfnh phg thuOc rd't nhigu vdo kfch " g " thudng dgpc dung treng xQ ly hd'p thu cdc chd't co thudc hgt oxit sdt tQ chg' tgo dQpc. mdu vd mui [11].

Phd bie'n nhdt trong cdc togi vgt tigu Id nhga trao ddi Jrong nghign cQu nay, than hogt tfnh tQ tfnh da dupc anion tQtfnh. Dgc digm ehung eua logi nay la khung cao ehe tgo bdng cdch dieu chg' oxit sdt tQ cung vdi than phan tQ cd ChQa cdc nhdm tfch dign dQdng vd bae bpc hogt tfnh vd Qng dgng d l logi chd't mdu hQu ed trong cac hgt cd tQ tinh [3-6]. Cae vgt ligu nay da dupc Qng nghg phlm nhupm vdi uu digm thdi gian ldng rd't nhanh dgng rOng rai treng xQ ty nQdc, dgc bigt higu qud vdi de cd tQ tfnh cao.

H. THVC NGHIEM

1. Tong hcjfp oxit sSt tiif dm dUpc mdu vdt tigu A.

3 p^huong phdp dieu ehg' oxit sdt tQ da dQpc nghign PhUdng phip 2: Hda tan 2,78 gam FeS04.7H20 trong cifu gdm: 100mt nQdc ndng d 98°C. Tig'p tgc rdt tQ tQ dung djch

PhUdng phip 1: Hda tan eung luc 0,025mot FeS04 ^^^^ ^,'^^^°^ ^9^: ^^^^^ '^{^ ^^ '^^^ ^.^^"^ ^^°J^^^

7H2O va 0,025mol Fe(N03)3.9H20 trong lOOmt nudc ed't ^id. RQa ggn kgt tug 3 tan bdng ngdc cgj, giQ ket tua Thgm tQ tQ dunp djch chQa 0,2mol NaOH vde dung djch ° ^^^^ ^^^^ ^^^ *^°"9 ^" '^"'^' ^^'^^ ^^^ "^^ ''^"^ ^•

hdn hpp trgn va dieu chinh pH dg'n 11. Sau khi ket tua PhUdng phip 3: Sgc khf N2 vde binh ndn chQa SOmt hoan todn, tpc hgt chdn khOng. RQa s^ch ket tua thu nude ed't ddpc dun trgn bgp khudy tQ d 90°C. Thgm dQpc, sdy d 80°C treng 2 ngay, Id'y ra dg trong binh hut 2,78 gam FeS04.7H20 vdo binh ndn, sau dd nhd tQ tQ

Hoa hpc & Ung dung

o Si 16 (ioo)/2oog

tQng gipt dung djch KNO3 vg KOH tQ phgu chig't vao binh ndn, sgc khi N2 thgm 20 phut va dun ndng ddng thdi khud'y dgu treng 1 gid. RQa ggn sdn phdm 5 tdn bdng ngdc Ignh. Thgm nudc cdt vgo huygn phu dgn thg tfch lOOmt, giQ sdn phdm d 4°C.

2. Kiem tra thanh phSn oxit sdt

Hda tan mdt IQpng exit sdt digu chg' dupe bdng hdn hpp H2SO4 25% va H3PO410%, djnh mQc dg'n thg tfch

chfnh xdc, sau do xae djnh ddng thdi ham tgpng Fe(lt) vg Fe(ltt) bdng phQOng phdp trdc quang sQ dgng hdn hpp thud'c thQ axit salysilic va o-phenantrolin [12].

3. Kiem tra tinh chS't tiif tinh cua v^t lif u

DQdng eong tQ hda eua ede miu dd bdng phUdng phdp tQ kg dign rung. TQ dQdng eong nay, tinh dQpc momen tQ bao hda.

III. KET QUA VA

T H A O

LUAN 1. Ddc tinh cua oxit sdt tuf

Trong 3 phQdng phdp dieu ehg' exit sdt tQ b trgn, miu vgt tigu A digu ehg' thee phuong phap 1 d dgng bgt mjn, khO, mau ngu den, ed hgt phg thuOe vdo qug trinh nghign. Miu vgt tigu B dieu chg' thee phuong phap 2 se khdng kigm sodt dupe ty Ig Fejtt) vg Fe(ttl) trong oxit, sdn phdm ban ddu d dgng xOp bOng, sau dd chuyen ddn sang dgng hgt. Theo phUdng phdp 3 digu chg dupe cac miu vgt ligu oxit sdt tQ cd ky higu tQ C, dg'n Cs. Cie oxit digu ehg thee cdch ndy d dgng hgt mjn kfch cd

khodng 0,5mm, ban ddu d dgng xO'p sau dd chuyen sang dgng hgt mjn, cd hgt deu. Nhu vgy cgc oxit nay rdt thfch hpp dg dQa vao cao phdn tQ eua cdc ehdt hdp thu, giup gidm kfch thudc hgt vgt ligu.

2. Phan tich ty If Fe(II) va Fe(III) va kif'm tra tuf tinh cua vSt lif u

Bing 7 td ty Ig hdm lupng Fe(tl) vd Fe(ltt) trong cdc miu oxit Udt va khd khac nhau vd gia tn md men tQ M, (emu/g) cua vdt ligu khi dgt trgng thdi bad hda.

Bing

Miu oxit Fe(tl): Fe(ltt) tVliu udt Fe(tl): Fe(ttt) Miu khd Ms (emu/g)

f; Ty IQ Fe(ll) vi Fe(lll) trong thdnh phd

A -

1:14,8

-

B 1,9:1

1:3,8

78 C, 1,9:1

1:4,3

-

Cz 1,0:3

1:4,6

56 C3 1:1

1:5,5

-

n oxit sdt tir vd mO men tif

C4 1:2,1

1:5,3

63 Cs 1:1,3

1:4,1

62 Ce 1:2,2

1:4,4

63 C;

1: 2,3

1:10,1

-

Cs 1,5:1

1:4,5

61

(cic miu ghi ky hi^u - W cic mSu khdng tien hinh xie djnh)

Kg't qud trgn cho thdy, d phuong phdp 1 vd 2 vdi cgc miu oxit A va B, ty tg Fe(tt): Fe(tlt) khdng kiem sodt dupe do khi sg'y khO, oxi khOng khf da oxi hda Fe(tl) thanh Fe(ltt). Theo phQdng phdp 3 khi dung ehd't oxi hda td Kt\l03 kg't hpp vdi KOH se thu dQpc ty Ig Fe(tt):

Fe(lll) ^dn nhu mong mud'n. Tuy nhign, ty Ig ndy bj thay ddi khi sdy vl vgt ngn glQ vgt ligu d 4°C.

Ket qud do tinh cua cac miu vgt ligu B, C2, C4, C5, Ce va Ca thu dupe d hinh 1 (trang bgn) cho thdy tQ tinh kha cao va dn djnh. Vdng tQ trg chQng td dgy Id cdc oxit sdt ed tQ tinh va thfch hpp de dQa vao cac

vgt ligu hdp thu.

3. Ki§'m tra thcfi gian ldng cua oxit sdt

Ldy cae miu vgt ligu dieu che theo phuong phap 2 vd 3, thgm nude cdt, dg ldng tg do va dg ldng trong tQ trgdng bdng each dgt tgn trgn nam ehgm. Kg't qud thu dupc d bing 2 (trang bgn) eho thd'y ng'u khdng cd tQ trQdng thi oxit dieu ehg'theo phUdng phap 3 khi cd chdt oxi hda NO3 nhanh hdn theo phuong phap 2. Do vgy phuong phap 2 va phQOng phgp 3 se dQpc diJng de dieu che than hogt tinh tQ tinh.

Hoa hpc & Ung d u n g

Si 16 {ioo)l20og

_{' ^}

M & u C j

70-

u-

3 » 3 0 ' JO - 0 -

.-' / -

1 l'.'' j ' *

1 1 1 1 1

2 3

MauC^

M i u C ,

M a u B

II<Kw>

MauC<

M^u d

Hinh 1: Difofng cong tU hoa va vong tiif tre cua oxit sdt tuf

o Hoa hpc & U n g d u n g

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Bing 2: Thdi gian ldng (phut) cua oxit sdt tir

Miu

Ldng tg do Dgt vao tQ trupng Hign tgpng

B 60 2

Ldng xudng day, hgt xd'p Ci

15 2

Cz 15 2

Ca 15 2

C4

15 2

Cs 15 2

Ce 15 2

C7

IS 2

Ce 15 2 Ldng sat xudng day, hgt mjn

4. VSt lif u hS^p thu tiif tinh va u^ng dung a) Dieu che than ho^t tinh tCl tfnh

Vgt li$u than hogt tfnh tQ tfnh dQpc digu ehg' theo phuong phap 2 vd phQdng phap 3 da md td d trgn, chi khac la ban dau cd thgm 0,5 gam than hogt tinh sigu mjn. Theo phuong phap 2 vdt tigu thu dupc d dgng huygn phij hoi xO'p (vgt ligu Tl). Con theo phuong phdp 3_, sau khodng 20 phut, nhOng hgt vgt ligu mau den lang hg't xudng ddy, hgt mjn hon nhung phdn than id iQng tang (vdt tigu T2). Vi vgy cdn tang td'c dg khudy.

b) XAc djnh thhnh phan cua than hoat tfnh tu tinh

Ldy 0,5 gam vgt ligu udt (giQ 6 4°C) vao cd'c chju nhigt 2S0ml, thgm nude cat de'n 10ml va them 2ml H2SO4 dgc. Ngam 4 gid trong nudc dm, lpc qua gia'y Ipc bang xanh vao binh djnh mQc SOmI, lie deu. Ket qud xac djnh ty Ig ndng dp Fe(lt) va Fe(lll) trong dung djch tuong Qng la 1 : 1,3 (vdi vgt ligu Tl) va 1 : 1,6 (vdi vgt ligu T2). Dieu nay chQng td cd thg dieu chinh lupng chdt oxi hda d phQdng phap 3 dg tang IQpng Fe(tlt) trong vgt ligu tQ tinh nhdm tgo vgt ligu hdp thu dgt higu qud cao nhdt.

c) Danh gii khi nSng ling cua vat li$u tU tfnh Thf nghigm vPi 3 togi vgt ligu hdp thu Id 2 logi than hogt tfnh tQ tfnh chg' tgo theo phQdng phdp 2 (vgt ligu Tl) va than hogt tfnh tQ tfnh chg' tgo theo phQOng phap 3 (vgt ligu T2) dd'i chQng vdi tha_n hogt tfnh thdng thQdng. Sau dd thQ dp ldng cua mdi logi vdi chdt can xQjy trong cdng nghg dgt nhupm la tfm tinh thg' (CV).

Mdi logi vgt ligu igy 0,5 gam pha trong 100ml nudc, IQpng tim tinh thg' thf nghigm la 200mg/L.

Ket qud thgc nghigm eho thdy 2 logi vgt ligu than hogt tfnh tQ tfnh che tgo dQpc cd thdi gian tg ldng nhu nhau (25 phiit) va nhanh hdn nhieu lan so vdi than hogt

tinh thdng thudng (240 phut). Khi cd tQ trQdng cd hai vgt ligu nay chl edn 5 phut la ldng hodn toan. Khi cd tim tinh the thi ed hai togi vgt ligu nay dgu ldng rdt nhanh (10 phut), pha nude trgn b l mgt vgt ligu trd ngn trong sud't eon than hogt tfnh cdn 180 phut mdi ldng, trong khi dung dich vin rg't dgc.

d) Dung lU0ng hap thu tfm tinh the ct/c d$i cua than ho^t tinh tU tinh

Ldc deu SOmI huygn phu cua hai logi vgt tigu da dilu chg' d trgn, la'y 2ml huygn phu vao cac binh ndn dung tfch SOmI, thgm vao cae binh dung djch tfm tfnh the (CV) cd ndng dp bie'n ddi tQ ISmg/L den 220mg/L, ldc cac dung dich vdi td'c dp 80 vdng/phut trong 4 gip d nhigt dp phong. Lpc phdn dung djch trong vd do dp hap thg quang cua dung dich d budc sdng cgc dgi cua tim tinh the (X = S90nm)^vdi dung djch so sanh la nude cat. Dga vao dudng chuan se xac dinh dupe IQpng tim tinh thg' chQa bj ha'p thu. Dung lupng hdp thu cua vgt ligu dupc tinh tlieo phuong trinh Langmuir nhu sau:

P b X q„3^ q ^ ^ Trong dd: C: la ndng dp cuO'i (mg/L);

q va q^a,: Id lgpng tfm tinh thg hdp thu trgn vgt tigu tQ luc can bdng vd IQpng cQc dgi;

b: la hg sd hg'p thu.

Dgng dudng bigu dign ed dgng y = A + Bx vdi y = C/q va X la ndng dp ti'm tinh thg' ta se ed b = tga = Mq^^

tQ dd se tinh dQpc dung lupng hg'p thu cgc dgi q^„.

Ke't qud khdo sdt vdi vgt ligu Tl cho tha'y cQ 2mt huyen phu se vgt ligu nay hdp thu thu dupc tdi da 3,9mg tim tinh thg hay 19Smg CV/g vgt ligu. Khao sat tuong tg vdi vgt ligu 2 se tfnh dupc dung lupng ha'p thu cgc dgi la 220mg CV/gam vgt ligu.

IV. KET LUAN

Cdng trinh nay da nghign cQu ehg' tgc thdnh cdng than hogt tinh tQ tfnh trgn cd sd dieu chg' oxit sdt tQ bang each ket tua hydroxit sdt tQ mud'i sdt (II) va sdt (III) cd mgt chdt oxi hda KNO3 cung vdi than hogt tfnh va say khd d 80°C. Theo each nay than hogt tfnh tQ tfnh dieu chg' dupc cd tQ tinh khd cae vd dn djnh, ldng rd't nhanh d trgng thdi tg de (15 phut) vd khi dgt trong tQ

trQdng (2 phut). Vgt tigu nay da dupc dung dg hdp thu tim tinh the vdi dung tupng hg'p thu cgc dgi khodng 220mg tim tinh thg'/gam vgt ligu. NhQng kg't qud nay eho thdy cd the Qng dgng than hogt tinh tQ tinh trong xQ ly mdi trudng ndi chung va xQ ly cac chat thdi nganh cdng nghigp dgt nhupm ndi rigng.

(Xem tiep trang 47)

H o a h p c & U n g d u n g

5 / 1 6 (lOo)/20og

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IV. KET LUAN

Chung tOi da nghign cQu tgo gia vj mi an lign chua cay tQ nguygn ligu: Id 1,4g trOn vdi mud'i 1,2g, mi ehfnh 0,8g, dt 0,2g; vd qud bQa khO 0,1 g trOn vdi mudi 1,2g, mi ehfnh 0,8g, dt 0,2g. Kg't qud ddnh gid edm quan cho thdy 02 logi gia vj nay phii hpp vdi thj hig'u ciJa ngudi Vigt Nam, dgt chg't lgpng vdi gia vj mi an lign, digm ehdt IQpng 13-13,1 diem vd diem trung binh cija cac chl tigu ChQa cd trpng IQpng 4,2 - 4,7 digm (IPn hdn

2,8 digm). Bdng phQdng phap sdc ky Idng cao dp (HPLC) da chl ra rdng cdu true cua axit (-) hydroxy xitric khdng thay ddi trong 02 logi gia vj tg tgo va hoan todn cd the Qng dgng Idm gia vj mi an lign mpt each an toan.

TQ ket qud nay ed thg Qng dgng td vd vd qud bQa dg lam gia vj eho mi an liln chua cay vQa ed tdc dgng ngon migng vQa eo tdc dgng chQa tn beo phi.

TAI LI$U THAM KHAO

1. Ddo Hung Cudng, Dgng Quang Vinh (2007), "Xie djnh axit hdu cd tU li, vd qui bUa bing sic ky ldng eao ip", Tgp ehf Khoa hpe vd Cdng nghg - Dgi hpe Dd Ndng, 3 (20), tr 137-143.

2. Jena BS, Jayaprakasha GK, Singh RP, Sakariah KK. (2002 Jan 2), "Chemistry and biochemistry of (-)- hydroxycitrie acid from Garcinia", Journal of Agricul-

tural and Food chemistry, 50(1): 10-22.

3. TCVN 5604-1991: Sin phim thUe f}him vi gia vj - Diiu kiin chung de tien hinh dinh gii cim quan.

4. TCVN 3215-1979: Sin phim thi^c phim - phin tfch dm quan - phUdng phip cho diem. *

NgUdi phdn bifn: GS, TSKH NGUYEN DINH TRI^U

::.*'^

l.^"'

NGHIEN cufu CHE TAO...

(Ti^p theo trang 37)

TAI LIEU THAM KHAO

[1]. Robert, C, Handly, A modern magnetic material and applications. A Wiley- tnterscience publication, NewYork. 1998.

[2]. Chow, C, Cook D., Drikas M., Evaluation of mag- netic ion Exchange resin (MIEX) and alum treatment tor formation of disinfection by products and bacterial growth.

Water Science and Technology, 2(3), 267 - 274 (2002).

[3]. Moran J.Y., Bursilt O.B., Drikas M., Nguyen H., Sim- ple method to reduce disinfection by product formation. Aus- tralian water and wastewater Association, 11th federal conference prxeeding, Melbourne, Vol. 1 526 - 530 (1997).

[4]. Moran J.Y., Bursilt O.B. Y., Drikas M., Nguyen H.V.. A new technique for removal of natural organic matter. AWWA Watertech. conference proceeding, Syd- ney, 428-432 (1996).

[5]. Nguyen H.V., Bursilt O.B., Drikas M., Moran J.Y., THM and drinking water- A new process for re- moval, Envir. Material 94, 19-21, Oct. proceeding Ku- talampur, Malaysia, p.59.

[6]. Nguyen H. V., Lunjki M., Bourke M.t., Drikas M., DOC removal by MIEX TM Process scaling-up and other development. Water and wastewater Association, Pro- ceeding 16-21 march, Melbourne, Australia, 373- 379.

[7]. Abrit 0., Yakup M. A., preparation and character- ization of magnetic potymethyl methaelylate mierobeads carrying ethylene polyamide for removal of Cu(tl), Cd(tt), Pb(ll) and Hgfll) from aqueous solution. Journal d Ap- plied polymer Science, Vol. 78, 81-89, (2000).

[8]. Young K. K, Kun J. L., Synthesis of a magnetic composite resin and Cobalt removal Characteristics in aqueous solution. Journal of Nuclear science and tech- nology. Vol. 38, No. 9, 785-792 (2001).

[9]. Towler P. G., Smith J. 0. Dixion D. R., magnetic Recovery of Radium, lead, and Polonium from Seawater samples after Preconeentration on a magnetic adsor- bent of MnO, coated magnetic. Anal. Chem. India. Vo.

328, 53-59 (1996).

[10]. Tran Van Nhan, Ngd Thj Nga. Giao trinh cdng nghg xQ ty nQdc thdi. Nhd xudt bdn KHKT (1999).

[11]. Hoang QuO'c Trupng, Cao Thj LTnh. Hda hpc thuo'c nhupm. NXB KHKT (1995).

ri2].Sajavi A., Abdollahi H., Speciation of Fe(ll) and Fe(ltl) with chromogenie Mixed Reagents by principal Component Regression. Mierochemical Journal. Vol. 63, 211-217 (1997).*

Ngudi phan bi^n: TS DO QUANG TRUNG

H o a h p c & Lfng d u n g

5*" 1 6 (ioo)/20og

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