Nghiên cứu, xác định hàm lượng kim loại nặng trong các mẫu nước bằng phương pháp trắc quang

l S S > n ^ 9 - 3070 Cac cong trinh nghign ciru Dia chat va Dja vat ly bien. Tap XT<br /> <br /> NGHIEN CUU, XAC DINH HAM Ll/ONG KIM LOAI NANG<br /> TRONG CAC MAU NlJOC BANG PHUONG PHAP TRAC QUANG<br /> <br /> Pham Thi Lan Huvn^, Le N^oc Anh. Do Thi So'n<br /> <br /> TOM TAT<br /> Trong thdi gian qua, nghien cim xdc dinh hdm luang kim logi ndng Irong cdc<br /> mdu nude vd ctia chdt clang Id vdn cfe dicc/c gidi chuyen mdn quan ldm. Phuang phdp<br /> trdc quang cu the la phicang phdp quang phd hdp thu phdn tie dmrc dp dung khd phd<br /> bien vd clem lai hieu qud cao trong phdn tich. Bdi bdo da di sdu nghien cicu, phdn tich.<br /> xdy dung cdc quy trinh chudn cfe xdc dinh hdm luang kim logi ndng trong cdc ddi<br /> tuang mdu bdng phicang phdp trdc quang. Cd the khdng dinh ddy Id mot phicang phdp<br /> cho ket qud cd do chinh xcic vd do lap Igi cao. cd y nghTa thuc le.<br /> <br /> I. MO DAU<br /> 0 nude ta, vdn dg d nhigm mdi tmdng da vd dang Id van dg lo ngai, quan tdm<br /> hdng dau trong thdi gian gdn ddy. Hdu nhu loan bd nude thdi, khi thdi d cdc cd san<br /> xudt, sinh boat hdng ngdy khdng qua xu ly dugc dd tryc tigp vdo mdi trudng. Cdc nhd<br /> mdy, xi nghiep ma dien, pin, thude da... hdng ngdy thdi vdo mdi trudng mot lugng ldn<br /> cdc kim loai ndng nhu Cu"\ Fe \ Mn"^ Pb"'', Cd~\ Ni~\ Hg^V--gay d nhigm nguon<br /> nude, ddi. Kim loai nang cung nhu cdc nguygn Id vi lugng khdc can thiet cho co the<br /> ngudi, dgng vat cung nhu cdc loai cdy trong. Song, ngu lugng kim loai Irong co thg<br /> qud mire cho phep do sir dung ngudn nude bj 6 nhigm se ddn dgn khd ndng bj nhigm<br /> doc cdp tinh gdy tir vong bode ddn tdi nhigu benh tdt nguy higm. Vi vay, viec xdc djnh<br /> ham lugng kim loai ndng trong cdc mdu dja chdt vd mdi trirdng Id rat cdn thigt. Ngdy<br /> nay, nhigu phuong phdp dugc dp dung xdc djnh ham lugng kim loai nang trong cdc doi<br /> tugng mau, trong pham vi cdng trinh ndy tdc gid da lua chgn vd sir dung phuang phap<br /> trdc quang.<br /> <br /> II. PHUONG PHAP NGHIEN ClTU<br /> Phuong phdp phdn tich quang phd hdp thi,i viing tir ngoai - khd kign (UV - VIS) Id<br /> phuang phdp dugc diing rdt rdng rdi trong cdc phep djnh lugng cdc nguyen to hod hgc.<br /> ILL Phu'O'ng phap phan tich sat (Fe): phuang phdp dua trgn nguygn ly tao mdu<br /> dd tia cua Fe^^ vdi o - phenantrolin vd cd cdng thirc [(C|2HsN2)2Fe]"'^. Xdc djnh trgn<br /> mdy trdc quang tai budc sdng 508nm. Phirc ndy bgn vd cudng do mdu khong ddi trong<br /> khodng pH = 2 - 9. Cdc ion cd phirc mdu tuong ty vd mdt so nguygn to khdc ngdn can<br /> viec xdc djnh Fe bang ihudc thir nay. Ag^^ Bi'^ tao kgt tiia, cdc ion Cd", Hg"" lao phirc<br /> khd tan vdi Ihudc thir. ddng thdi ldm giam cudng do mdu cua phirc. Co the ldm gidm<br /> dnh hudng cua cdc nguygn td Be, Sn, Cu dgn muc tdi thigu bang cdch hieu chinh pH<br /> mdi trudng trong khodng hep td 3 dgn 5 [3].<br /> <br /> 119<br /> Cac cong trinh nghien ciru Dja chdt va Dja vat ly bign. Tap XI ISSN_K>5^- 3070<br /> <br /> IL2. Phuong phap phan tich mangan (Mn): Ion pemanganat (IVlnOj) cd mdu<br /> tim dac trung vd hdp thu dnh sdng rdt manh. Chang ban. cd thg dung pcsunfat dg oxi<br /> hod Mn(ll) khi cd ion .Ag' ldm xuc tac. Phdn ung xdy ra nhu sau:<br /> 2Mn^" + 5 S , 0 ^ " + 8 H 2 0 - » 2 M n O ^ + lOSO^" + 16H^<br /> Ngu trong nude cd cdc ion khdc nhu CI", Cr207^", CiC^, Ni""^ Id cdc ion dg tao<br /> thdnh kgt tua, tao mdu ldm cdn trd dgn phep do cdn phdi loai trir. CI 'thudng dugc loai<br /> trir bdng AgNOs tao thdnh kgt tua trdng AgCl, Igc loai bd ket tua. Fe"^"^ dugc loai trir<br /> bdng H3PO4 (1:4). Cdc ion Cr207^", Cu^"", Ni^^... dugc loai tru bdng cdch do quang<br /> dung djch hai ldn [2].<br /> 11.3. Phuong phap phan tich dong (Cu): Cu"^ phdn ung vdi dung djch<br /> dithizone trong djch axit vd co loang pH = 3-^5 tao phuc mdu dd tim cd hap thy cue<br /> dai d budc song 400 nm [3].<br /> H.4. Phuo'ng phap phan tich chi (Pb): Ditbizon - Dipbenyltbiocacbazon Id<br /> thuoc thu biin co cd khd ndng tao phirc cdng cua vdi ion Pb. Trong CCI4 Pb dithizonat<br /> CO mdu dd, cyc dai hap thu d 520 nm. Pb dugc chigt chgn Igc va djnh lugng tu dung<br /> djch nude cd pH= 8-^9 chira lugng du CN" Id chat dung dg che cdc kim loai khdc ciing<br /> bj chigt vdi Pb la tali, biiiiut vd tbige (II) [2].<br /> IL5. Phuong phap phan tich niken (Ni): trong nidi tmdng kigm NH3, khi cd<br /> mat chat oxi hda manh (Bi^) thi Ni""*^ Ni''^. Ni'^* phdn ung vdi thuoc thir<br /> dimet)lglioxiin tao thdnh hgp chdt co phuc mdu dd, hdp thu cyc dai d budc sdng 510<br /> nm. Fe ', Cu''^, Cr ^ khdng tham gia phdn ii'ng vdi thude thir dimetyiglioxim nhung<br /> Idm djch chuygn mat do quang ciia phiic. Loai Fe"^, Fe^ bang cdch thgm vdo dung djch<br /> mdu, H2O2 3%, dun sdi man dg ngudi, ldm kgt tua Fe^ bang NH3 roi Igc bd kgt hia.<br /> Croniat \a dieomat dugc loai bo bdng cdch thgm H2O2 trong nidi trudng axit dg Cr^^-><br /> Cr"'. Sau do, thgm NH3 dc ket tua Cr(0H)3 rdi Igc bd ket tiia. Cic' dugc loai bd bang<br /> cdch axil hoa mdu bang HCl dgn pH =- 0.5, sue H2S dg kgt lua CuS, Igc bd kgt tua [2].<br /> II.6. Phu'O'ng phap phan tich kem (Zn): dg xdc dinh Zn bang phuang phdp tide<br /> quang dung dithizone (DZ) ngudi ta chigt phirc (Zn - DZ) bang CCI4 bdng mdi tm'dng<br /> kigm manh. Dung djch dithiozat cua Cd trong dung mdi hdu co cd mdu dd hap thu cyc<br /> dai d budc sdng 515 nm [2].<br /> III. KET QUA NGHIEN CUU<br /> III.L Xay dung dudng chuan<br /> Tign hdnh pha dung djch chudn (dung djch gdc) cho Cd. Cu. Fe. Mn, Pb, Ni vdi<br /> nong do Ig'l (hay 1000 ppni). Tir dung djch gdc, pha loang dg thu dugc cdc dung djch<br /> cd nong do Id: 0,1; 0,5; 1,0; 1,5; 2 ppm. Dua vdo mdy do ldn lugt (khi da lap ddy dii<br /> digu kien do), ihu dugc cdc dudng chudn ciia tdng sdt, Mn, Cu, Pb, Ni vd Zn (Hinh I 2<br /> 3,4,5,6):<br /> <br /> <br /> 120<br /> ISSN 1859-3070 Cae ciing trinh nghien ciru Dja chat \ a Dia vat ly bien. Tap XI<br /> <br /> <br /> <br /> <br /> 0,5 1 1.5 0.5 15 2.5<br /> <br /> Nong Do( ppm ) Nong Do { ppnn )<br /> <br /> <br /> Hinh I: Dd thj dudng chudn cua tdng sat Hinh 2: Dd thi dudng chudn ciia mangan<br /> <br /> <br /> <br /> <br /> 0,5 1 15<br /> Nong Do ( ppm } No n g Do ( p p m )<br /> <br /> <br /> Hinh 3: Dd thj dudng chudn cua ddng Hinh 4: Dd thi dirdniz chudn cua chi<br /> <br /> <br /> <br /> <br /> Q,t 05 1 15 2 0,5 1 15<br /> <br /> Nong Do (ppm) Nong Do ( ppm )<br /> <br /> <br /> Hinh 5: Dd thj dudng chudn ciia niken Hinh 6: Dd thj dudng chudn cua kem<br /> <br /> III.2. Xay dung quy trinh phan tich<br /> Dg xdy dyng quy trinh xdy dyng dudng chudn cdc thigt bj phdn tich cdn dugc<br /> chudn bj ky cdng, chudn xdc thi kgt qud thu dugc cd do chinh xdc cao. Vi kgt qud thu<br /> dugc la dudng chudn se quyet djnh do chinh xdc cua cdc kgt qua phdn tich mdu sau<br /> ndy. Dudi ddy Id quy trinh xdy dyng dudng chudn (Hinh7), quy trinh xu ly vd phdn<br /> tich mau nude (Hinh 8)<br /> <br /> <br /> <br /> <br /> 121<br /> Cac cong trinh nghign ciru Dja chat va Dja vai ly biin. Tap XI ISSN 1 8 5 9 - 3 0 7 0<br /> <br /> <br /> Can chinh sit ChoHNO.lhl C bo viu mi) do<br /> Cliuycn dd Thii diii/t dd rb]|gin;dil<br /> 0,5g Ihu dirm<br /> ctio den khi van JOtDBDfdo Ibudivccitdil<br /> kim loai 99,9% diiimj chiijn<br /> tan ht't binh dinb miic ItaMMBppml l,l;L\l;l,5;!ppiii<br /> <br /> <br /> <br /> Hinh 7: Quy trinh xdy dung dudng chuan<br /> <br /> <br /> Lay 500ral Them 5ml 1IN0.1 Dun Irong tu ho! ThmMHCI ThcmSnilllNO.l<br /> niroc mau \ao vaSmlllCI cho bay hoi den tccandtnmioijin va<br /> coc chiu nhiet dun Iren hep khi man con ?ml d( n^noi Diro'c cai 2 lan<br /> <br /> <br /> Chuyen vao I? niomHiiDt<br /> dmijmau jtlmliirairttil<br /> da difuc danh sii ligdiciiiliDiiic<br /> <br /> T&lnlintemi<br /> *\ tlori! lie Jill ri 11M<br /> lilt.fL'iilliiil<br /> <br /> wiJilmjIils!<br /> iklGiUimlliiii<br /> BO lilt, ill liif If pill<br /> <br /> <br /> QoyBIvidit<br /> iliiiliii{ilin](l}l>EoiiD<br /> dilioplmii<br /> Loc miiii bang<br /> ni.ing (buy (inb<br /> dinb mire 50ml<br /> <br /> <br /> <br /> Do do hap Ihu<br /> ddabuacsong<br /> Ihieh ho'p cua kL<br /> <br /> <br /> <br /> ,\ic dinb nonj do<br /> kim loai<br /> lir diriras choin<br /> <br /> <br /> <br /> <br /> Hinh 8: Quy trinh xir ly vd phdn tich mdu nude<br /> Mdu nude phdn tich lay tai hien trudng dugc dung ddy binh, niit chat trong binh<br /> thiiy tinh bode nhua sach polyetilen. Trudc khi dyng, binh dugc trdng ky 2 - 3 ldn bdng<br /> nude sap dyng. Dg phdn tich hdm lugng cdc kim loai ndng nhu Cu, Pb, Zn, Mn, Fe,<br /> Ni...thi ham mdu bdng cdch cho vdo binh dung mdu 5iiil HNO3 dac.<br /> Rigng cdc man phdn tich Pb, Cu, Zn sau khi da dugc xu ly mau, cd qud trinh<br /> phdn tich rigng dudi day (Hinh 9):<br /> <br /> <br /> <br /> <br /> 122<br /> ISSN 1859-3070 Cae eong trinh nghien ciru Dja chat va Dja vat ly bien. Tap XI<br /> <br /> Cho 50ml mau<br /> \aococ<br /> dinh mire 250ml<br /> <br /> <br /> 'r<br /> <br /> <br /> ecu V3 dii ecu va Mum<br /> pll=!,3<br /> —icy><br /> i 1'<br /> <br /> <br /> Pha ecu Pha nu'irc Pha niro'c<br /> CCH l i cirbanule<br /> Dung dich KI ecu aciibanuli'<br /> H:O liipll-SJ<br /> I; pll=8.3<br /> ' 1'<br /> <br /> <br /> Pha ecu PhaCCll PhaCeil<br /> NH4()110,01M<br /> 1110 HCl 0,02 ,\1 HCl 0,02 .M<br /> f<br /> <br /> <br /> <br /> Pha ceil PhaCCll Pha niro'c<br /> Cong pha avit CCHucaibmil! CCH i carbanult<br /> liiplhSJ 11 p l b U n<br /> 1f '<br /> DDIICl PhaCCll Pha ecu<br /> ecu icarbiDult NH4OH0,0IM<br /> 1? pH = !,5 m iMI4OH0,01M<br /> m<br /> \' 1<br /> r<br /> PhaCCU Pha ecu Pha ceil<br /> <br /> Cu lai JOOnm Zn tai 535nni<br /> r<br /> PblaiJlOiim<br /> <br /> <br /> Hinh 9: So dd phdn tich Cu, Pb, Zn<br /> III.3. Ket qua phan tich<br /> Cdc kgt qud phdn tich thu dugc trong bdng I dd dugc dp dicing dung quy trinh<br /> phdn tich d tren. Ddy Id cdc mdu phdn tich dugc thu thdp tir cdc mdu nude ciia cdc bai<br /> gigng nude tai I Id Ndi (Luang Yen, Nggc Hd, Tuong Mai, Ngd Sy Lign, Ygn Phu) tai<br /> cdc thdi diem khdc nhau.<br /> Bdng 1: Kgt qud phdn tich cdc mdu nude tai cdc gigng nude tai Hd Ndi<br /> STT Ky hieu EFe Mn Cu Pb Ni Zn<br /> mau (ppm) (ppm) (ppb) (ppb) (ppb) (ppb)<br /> 1 THB- 1 2,54 0,40 21,53 33,73 8,07 2,51<br /> 2 THB - 2 6,81 0,46 11,85 31,85 7,86 2,35<br /> 3 THB-3 4,85 0,94 7,72 33,62 5,92 2,63<br /> 4 THB-4 5,15 1,20 7,50 35,37 10,54 2,94<br /> 5 THB-5 2,54 0,42 15,94 37,02 8,77 3,08<br /> 6 THB - 6 2,31 0,14 20,32 36,32 7,87 2,21<br /> 7 '^ THB - 7 4,96 0,15 10,73 44,12 8,31 5,74<br /> 8 THB - 8 8,98 1,02 7,77 34,06 5,89 6,55<br /> <br /> 123<br /> ( ac cong trinh nghien ciru Dia chat \a Dia \'at ly bien. Tap XI ISSN 1S59-3070<br /> <br /> 9 THB - 9 4,37 0,22 6,29 29,87 5,46 2,45<br /> 10 THB - 10 3.67 0,07 1,36 43.46 6,10 2,78<br /> 11 THB - 1 1 6.23 0,83 6,55 40.78 7,44 3,24<br /> 12 T H B - 12 4,25 0,67 11,28 25.89 6,98 3,11<br /> 13 T H B - 13 7.17 1,35 7,98 34,88 5,89 2,37<br /> 14 T H B - 14 5,64 0,54 8,34 29.87 11,42 2,67<br /> 15 T H B - 15 3,85 0,34 9,01 44,67 3,87 7,83<br /> 16 T H B - 16 1,22 1,31 8,23 36,78 5,46 12,34<br /> 17 T H B - 17 5,17 0,59 11,52 39.03 7,35 2,58<br /> 18 T H B - 18 3,95 0,24 9,56 47,98 6,93 5,68<br /> 19 T H B - 19 2,29 0,78 6,78 28,62 9,67 9,71<br /> 20 THB - 20 4,74 0,54 15,34 39.56 9,48 2,53<br /> 21 THB -21 9,03 0,97 12,56 35,11 8,67 1,92<br /> 22 THB - 22 2,88 0,78 8,63 36.82 10,33 13,24<br /> 23 THB - 23 3,45 0,77 6,59 38,67 7,83 6,34<br /> 24 THB - 24 5,21 0,63 7,56 40,78 9,66 2,64<br /> 25 THB - 25 1,18 1,04 6,88 38,54 8,37 1,89<br /> Kgt qud cho thdy hdm lugng cac kim oai ndng trong cdc mau nude phdn tich<br /> nhin chung cdn ndm trong gidi ban cho phep. Rigng chi cd Fe, Mn cd ddu hieu da bi d<br /> nhigm cdn phdi xu ly tdt 2 kim loai ndy trudc khi dua ngudn nude vdo xu dung.<br /> <br /> IV. KET LUAN<br /> Tir cdc kgt qud dat dugc cd thg rut ra mdt sd kgt ludn nhu sau:<br /> - Trong qud trinh nghign cuu cdc ygu td dnh hudng, chung tdi da xdy dung dugc<br /> quy trinh phdn tich, xdc dinh ham lugng kim loai ndng trong cdc ddi tugng man.<br /> - Phuang phdp phan tich trac quang Id phuong phap hien dai da dugc su dung<br /> rong trong cdc nghien ciru khoa hoc vd da Ididng dinh dugc tinh hieu qua ciia nd.<br /> - Viec dp diing quy trinh phdn tich ndy dg xdc dinh hdm lugng kim loai ndng<br /> trong cdc ddi tugng mdu da cho thdy kgt qud Ihu dugc cd do lap lai, do tin cdy cao.<br /> <br /> TAI LIEU THAM KHAO<br /> 1. Nguygn Tinh Dung, 2002. Hod hgc phdn lich. phan 111. Cdcphieoagphdp dinh<br /> luong hod hoc. NXB Gido Due.<br /> 2. Hd Quy Vigt, 2005. Cdc phuong phdp phdn tich cdng cu trong hod hgc bign<br /> dai. NXB Dgi hoc Siephgm.<br /> 3. Hd Quy Vigt, Nguygn Tinh Dung, 1991. Cdc phuang phdp phdn tich li - hod<br /> A'.\'5 Dgi hoc Sic phgm.<br /> 4. David Harvey, 2000. Morden analytical chemistry. Mc Grown Hill.<br /> <br /> <br /> 124<br /> ^SSN 1859 - 3070 Cac cong trinh nghien ciru Dia ehSt va Dja vat ly bign. Tap XI<br /> <br /> 5. H. A. Latine, 1976. Phan tich hod hgc, lap 2. NXB Khoa hoc vd Kilhiidt, Hd Ndi.<br /> 6. Hasan Cesur, Turk J C. em, 2003. 27, 307 - 314.<br /> 7. P. G. Brewer, D. W. Spencer. (Jan, 1971). Limnology and Oceanography, Vol.<br /> 16, No. 1 pp. 107- 110.<br /> 8. U. S. Department of health and human services. Seplcniber 2000. Agency for<br /> toxic substances and disease registry. Toxicologiccdprojile for manganese.<br /> <br /> <br /> SUMMARY<br /> Determination of the concentration of heavy metals in water samples<br /> by the method of spectroscopy<br /> By Pham Thi Lan Huong. Le Ngoc Anh. Do Thi Son<br /> <br /> <br /> In Ihe recent time, determination cf the concentration of heavy metals in Ihe<br /> samples of water and geology has been studied by many different researchers. The<br /> method of spectroscopy, namely the molecular adsorption spectroscopy is used quite<br /> widely for analyzing efjectively heavy metals. In this paper, the determination of<br /> heavy metals was investigated carefully and a standard protocol for analyzing was<br /> set up for the different kinds of sample by using the method of spectroscopy. From<br /> the result of research, this is the very usejul method with a high repeatability and<br /> hi