ĐỀ TÀI KHẢO SÁT PHƯƠNG PHÁP XỬ LÝ LÀM TĂNG KHẢ NĂNG HẤP THU CÁC ION KIM LOẠI NẶNG TRONG NƯỚC KHOÁNG BENTONITE VIỆT NAM

DAI HOC QUOC GIA HA NOI TRUING DAI HOC KHOA HOC Tl/NHIEN ^ : ) : ;J: ^ ^; ^ Jj: ^' -.'^ -N ^ ^ ^ -1^ ^ ^ ^ :i^ ^ ^ BAO CAO DE TAI KHAO SAT PHUONG PHAP XlTLI L A M N A N G HAP T H U CAC TANG KHA ION KIM LOAI NANG TRONG NUdc CUA K H O A N G BENTONITE VIET NAM Ma sd: Chii tri de tai: PGS TS Ng6 Sy Luang Can bg phdi hgp: TS Than Van Lien ThS Ha Van Van ThS Pham Van Tien CN Nguyen Thuy Mai DAI HOC Q U O C GlA HA NOi TPUNG TAt^ THOr.'G TIN THO VlFN DT J4 t Ha Noi 2005 PHAN L BAO CAO TOM TAT DE TAI BANG TIENG VIET Ten detai: Khdo sdt phuang phdp xir ly ldm tdng khd ndng hdp thu cdc ion kim logi ndng nUdc ciui khodng bentonite Viet Nam Ten tieng Anh: Research of treatment method to improve the ability of absorption for heavy metal ions on Vietnamese bentonite Chu tri de tai: PGS TS A^^^ Sy Luang Hgc ham, hgc vi: PGS TS Dan vi cong tac: Khoa Hod hgc Tel: 8241169 Cac can bg tham gia de tai: TS Than Van Lien Thac sy Ha Van Van Thac sy Pham van Tien CN Nguyen Thuy Mai Muc tieu va ngi dung nghien cuu: Bentonite la loai khoang set tu nhien, cd cau true Idp, cd dicn tfch be mat Idn nen cd khci nang hap thu tu m6i trudng nudc nhieu chat v6 ca va huu co Vl vay bentonite dugc ung dung nhieu ITnh vuc cd lien quan den kha nang hap thu cua no: xu li moi trudng, lam sach cac chat Idng khoi cac tap chat, che dung dich khoan, lam chat don Nudc ta cd triT lugng bentonite tuong ddi Idn, gdm mot sd mo nhu: Di linh - Lam Ddng, Thuan hai - Binh thuan, v.v Theo danh gia sa bg ham lugng montmonllonite khoang bentonite cua nudc ta kha thap Vi vay viec nghien cuu cac phuong phap lam tang ham lugng montmorillonite, ddng thdi hoat hoa de lam tang kha nang hap thu cua loai vat lieu nluTm muc dich tang kha lulng su dung ngudn tai nguyen phuc vu cho cac nganh kinh te qudc dan la mot van de rat dang dugc quan tam Mot nhung ung dung quan trgng cua khoang bentonite la sir dung nd lam vat lieu hap thu ion kim loai nang ITnh vuc xu If n^oi trudng nude Do vay, viec nghien cuu cac phuong phap hoat hoa lam tang kha nang hap thu eua bentonite ddi vdi cac ion kim loai nang la mdi quan tam cua nhieu nha khoa hgc va ngoai nude Bentonite cd mat dat, cd kha nang hap thu nen nd hoat dons nhu cac ludi loc tu nhien Khi nudc tham qua cac Idp dat thi bentonite giiTr lai cac ion kim loai \'a cac chat huu CO Vi vay, bentonite tu nhien bao gid cung da chi'ra sfin (du ft hoac nhieu) mot lugne nhat dinh cac chat da bi hap thu va vice loai bd cac chat de lam tang kha naiio hap thu cua bentonite trudc kin sudung la nhiem vu quan trgng De lam tang ham lugng ciia montmorillonite khoang bentonite, ngirdi ta thudni sir dung cac phuang phap tuyen khoang va phuang phap thudng dugc sir dung la tuyen trgn^ luc Hien cd mot sd phuang phap mdi dugc ap dung, vf du nhu tuye'n bang xyclon De hoat hoa lam tang kha nang hap thu cua bentonite, ngudi ta thudng su dung mot sc phuong phap sau: - Phuang hoat hoa bang nhiet: Dicing nhiet cao de loai nudc hap phu, loai cac cha huu ca khoi khoang bentonite - Phuang phap hoat hoa bang dung dich kiem: Dung dung dich kiem cd ndng thfcF hgp de xu If khoang bentonite - Plurang phap hoat hoa bang dung dich axit vo ca: Dung dung dich axit v6 co (thudng la axit sunfuric, axit clohydric) cd nong thfch hgp di xu If khoang bentonite Ccic phuang phap hoat hoa ndi tren dugc su dung mot each thfch hgp theo phfin, ham lugng montmorillonite bentonite va dac biet la thugc vao muc dfch sii dung Trong dd phuang phap hoat hoa bang cac dung dich axit sunfuric la dugc su dung nhieu nhai va cd hieu qua nhat 4.L Muc tieu nghien cuu - Ddi tugng nghien cuu la bentonite vung Di Linh - Lam D6ng va vising Tuy Phong Binh thuan Day la nhung vising co khoang bentonite co tru lugng thugc loai Idn nhat nude ta hicn - Tim phuoug phap thfch hgp nang ham lugng montmorillonite bentonite - Tim dieu kien tdi iru cho qua trinh hoat hoa bang axit nham lam tang kha nang hap thu ciia bentonite ddi vdi cac ion kim loai nang mdi trudng nirdc Nhu vay san pham bentonite sau hoat hoa nham muc dfch xu If moi trudng: tach loai cac ion kim loai nans tu moi truoug nuac, - Khao sat kha nang hap thu cac ion kim loai nang ciia bentonite dung dich nudc 4.2, Ndi dung nghien cuu - Phan tfch phfin khoang va phan hoa hgc cua man bentonite nghien ci'ru - Kluio sat phuang phap lam sach va hoat hoa bentonite bang axil H^SOj cd ndng va dieu kien thfch hgp de lam tang kha nang hap thu cac ion kim loai nang tromz nude - Khao sat kha nang hap thu ciia bentonite sau xu ly va so sanh vdi kha nang hap thu ciia bentonite nguyen khai chua xu ly Ciic kel qua da dat dugc g Anh hudng cua cdc chdt dien li moi trudng nudc Chuang II Phuang phap nghien cu*u 2.1 Phuang phap hoat hoa quang 2.2 Phuang phap phan tfch phan hoa hgc ciia bentonite a Xdc dinh hdm SiO^ b Xdc dinh hdm FeiO:^ c Xdc dinh hdm luang AFOj d^Xdc djnh MgO vd CaO 2.3 Phuo'ngphdp xdc dinh sdt, mangan dung dich a Phuo'ng phdp trdc r/uang xdc dinh ndng ion sdt dung dich vdi thudc thir thioxianat b Xdc dinh mangan bdng phuo'ng phdp trdc c/uang 2.4 Phuang phap xac dinh hap dung cua cac ion kim loai tren bentonite Chuang III - Ket qua va thao luan 3.1 Khao sat cac yeu td anh hirdng den kha nang hap phu cac ion kim loai nang moi Irudng nirdc cua bentonite 34.FF Anh hudng cua pH dung dich dcdi khd ndng hdp phu Fc'^ vd Mm^ tren bentonite 3.1.2 Anh hudng cua thdi gian khuay tdi sUhdp phu Mm^vd Fc'^ tren bentonite 3.1.3 Anh hudng ciia ndng chdt bi hdp phu 3.F3 Anh hudng ciia ty le the tich ciui dung dich hdp phu vd khdi lugng be/itonite 3.2 Mau khoang bentonite sir dung de nghien cuu 3.3 Khao sat qua trinh hoat hoa bentonite 3.3.1 Logi axit 3.3.2 Ndng axit 3.3.3 TvleRIL 3.3.4 Nhiet hogt hod 3.3.5 Tdc khuay tron 3.3.6 Thai gicm hogt hod Ke't luan Tai lieu tham khiio MOiDAU Bentonite la loai khocing set tu nhien, cd ca'u tnic Idp, co dien tfch be mat Idn nen cd kha nang ha'p phu nhieu chat vo ca va hxiu ca [1,51 Vi vay bentonite la loai vat lieu dugc ii'ng dung nhieu ITnh vuc khac Nudc ta cd tru lugng bentonite tuang ddi Idn, d mot sd mo nhu: Di linh - Lam Dong, Thuan hai - Binh thuan, v.v Quang bentonite Viet Nam cd ham lugng montmorillonite kha thap, chat lugng kem, do viec nghien cuu lam tang chat lugng de cd the sir dung tdt han ngudn lai nguyen de phuc vu cho cac nganh kinh le qudc dan la mdt va'n de ra't dang quan tam De tang cudng cha't lugng cua khoang bentonite, cd hai van de can dugc tien hanh: - Lam tang ham lugng montmorillonite khoang bentonite Giai doan thudng ditgc tien hanh bang cac phuang phap tuyen khoang th6ng thudng, chu yeu la phuang phap tuyen trgng luc - Hoat hoa khoang bentonite sau lam giau de tang kha nang hap phu cua no De hoat hoa bentonite, ngirdi ta thudng sir dung cac phuang phap hoat hoa nhict, hoat hoa bang dung dich kiem, hoat hoa bang dung dich axil, dd phirong phap hoat hoa bang dung dich axit vo ca, nlur H2SO4, HCl dirge sir dung ph6 bie'n nhat De danh gia chat lugng bentonite sau lam giau va hoat hoa, phuang phap phd bie'n la danh gia qua kha nang hap phu cua bentonite ddi vdi cac ion kim loai nang dung dich nirdc Dong tlidi muc dfch sir dung bentonite lam vat lieu hap phu tach loai cac ion dd khdi m6i tnrdng nudc gdp phfin chdng nhiem m6i trudng cung la mdi quan tam hang dau ddi vdi cac nha nghien cuu nirdc va tren the gidi ITnh vuc [5-8] Xuat phat tu y tudng do, chung t6i dat van de khao sat kha nang lam giau va hoat hoa bentonite bang phuong phap axit, cu the la H2SO4 Muc tieu nghien cuu dirac dat de tai nghien cuu la tim dugc phuong phap xu If lam tang kha nang hap phu cua bentonite ddi vdi cac ion kim loai nang in6i tnrdng nudc Cac ngi dung nghien ci'ru dugc dat de tai nghien cuu la: - Phan tfch phan khoang va phan hoii hgc ciia mau bentonite nghien cuu - Khao sat phuong phap lam giau dc tang ham lugng montmorillonite khoan" bentonite - Khao sat phuang phap xu ly axit H.SO^ cd nong va d dieu kien thfch hop de lam tang kha nang hap phu cac ion kim loai nang nudc - Khao sat kha nang hap phii cua bentonite sau xu ly va so sanh vdi kha nang hap phu cua bentonite nguyen khai chua xu ly Cac thf nghiem nghien cu*u ciia de tai dugc tien hanh d phong thf nghiem Vat lieu mdi thugc bg mon Hoa Vo ca - Khoa Hoa hgc - Tnrdng DHKHTN - DHQG HN va phdng thf nghiem thugc Trung tam Xu If quang - Vien C6ng nghe Xa - Hiem thugc Vien Nang lugng nguyen tir Viet Nam Kinh phf cua de tai dagc DHQG HN cap qua de tai cap DHQG mang ma sd Chung t6i xin chan cam an DHQG HN da cap kinh phf de chung toi hoan cac ngi dung nghien cuu cua de tai CHUONG I GICJI THIEU VE BENTONITE I.GI6I THIEU VE BENTONITE LI Thanh phan hoa hgc cua bentonite Bentonite la loai khoang set tu nhien, co phan chfnh la montmorillonite Vi vay cd the ggi bentonite theo phfin chinh la montmorilonite Cong thuc dan gian CLia montmorillonite ALOv4Si02.nH20 I'mg vdi nua te bao don vi cau tnic Cong thuc ly tudng cua montmorillonite la SiyAl402o(OH)4 cho mot dan vi ca'u tnic Tuy nhien phfin cLia montmorillonite luon khac vdi phan bieu dien ly thuyet cd sir thay the ddng hinh cua cac ion kim locai nhu Fe"*"", Fe^"^, Mn""" vao vi trf cua Si"*"" tu dien Si04 va ciia Al"^^ bat dien AlO^ Nhu vay phfin hoa hgc montmorillonite, ngoai sir co mat cua Si va AI, ta cdn iha'yeo sir xua't hien ciia cac nguyen td khac nhu: Fe, Zn, Mg, Na, K, v.v , ty le ALQvSiO.tu 1:2 den 1:4 Ngoai phfin chfnh la montmorillonite, bentonite chua mot sd khoang set khac nhu liectorit, saponit va mgl sd khoang phi set: canxit, pirit, manhetit, cac mudi kicm va mot sd cha't huu ca khac 1.2 Cau tnic cua montmorillonite Trong c6ng thi'rc ly lirdng cua montmorilonite, cac nguyen tu Si nfim d mang tu dien, cac nguyen tu Al nam d tam mang bat dien (trong tnrdng hgp mang nhom silicat la trung hoa dien) va cong thi'rc khai trien cua nhu sau hinh O o ^ ^o o : Si1ic o o O : O xI Hinh! Cong thirc khai trien khong gian ciia montmonllonite li tirdng Do montmorillonite cd cau tnic 2:1 dang diocta nen cau tnic lap montmorillonite da dugc hinh tir hai mang tir dien lien ket vdi mot mang bat dien d giua, tao nen mgl Idp nhdm silicat vdi cac khe trdng d giua Cac cation co kha nang trao d6i bi hydrat hoa va nudc bi ha'p thu cd the chie'm cho d cac khe trdng giua cac lap nhom sislicat Chieu rdng CLia khe trdng giiJa cac Idp cau tnic ca ban ciia montmorillonite la 9,6 A, chidu rong dd cd th^ bi thay ddi ft hay nhieu thugc vao sd lugng, ban chfi't cation trao doi va lugng nude hap thu, thudng c6 the den 15 A So d6 ca'u tnic khong gian mang lircri ciia montmorillonite, dugc trinh bay tren hinh 2, la mgl cau tnic trung hoa dicn Neu Si"^^ ti'r dien hay AL"^ bat dicn bi thay the dong hinh bdi cac cation duong thap hon thi cac phan mang dd tfch dien am Dien am cao hay thap thugc vao sd lugng va ban chat cua cac cation thay the Dien tfch am cua mang se dugc bi^i tri^r bang cac cation mang dicn tfch duang Na"^, K"*^, Ca^"^, Fe""^, Mn""^ d khoang kh6ng gian giua cac Idp Nhu vay kha nang trao ddi cation cua montmorillonite la tuang dirang vdi dien tfch ciia cac Idp Ci* i i o o O.Va « SLLLc J h o j c trs.c ^ i -f nW^c nhom Hinh Sa dd cdu true khong gian nigng ludi cua montmorillonite 1.3 Cac kha nang bien tinh Bentonite 7.3.7 Bien tinh giir nguyen cdu true cda lop aluniinosilicat Dac trung ca ban cua bentonite la tfnh chat trao ddi Tfnh chat dd cd dugc la sir thay the ddng hinh Si'*'' bang Ah^"*" mang ti'r dien va Ah^^ bang Mg""" mang ludi bat dien lam xua't hien dien tich am mang ludi cau true Kha nang thay doi manh hay yeu phii thugc vao lugng dien tfch am be mat va sd lugng ion trao ddi Neu sd lugng dien tfch am be mat cang Idn, sd lugng cation trao ddi cang Idn thi dung lugng trao d6i cLia bentonite cang Idn Kha nang trao ddi ion ciia nhdm silicat phu thugc vao dien ti'ch va ban kfnh cation trao doi Dien tfch cation cang thap thi cang de trao ddi hon cation dien tfch cao Me^>Me2-^>Me^L Ddi vdi Ccic cation ciuig dien tfch, ban kfnh cang nho thi kha nang trao d6i cang Idn cd the xap xe'p theo trat tu sau Li > Na > K > Cu > Fe > Al Tuy nhien kha nang trao d6i cua nhom silicat chii yeu van phu thugc vao dien tfch am be mat va luanc dien tfch am iron" manti ludi Bentonite ^6m be mat Irons va be mat ngoai Kha nang trao doi ion be mat ngoai phan anh kfch thudc tinh the, phu thugc vao kfch thudc tinh the, phu lhuoc vao su di'rt gay lien ke't va khuyet tat be mat Kfch thudc hat cang nhd thi kha nang trao doi cang Idn Kha nang tiao d6i be mat phan anh lugng dien tfch am mang ludi va khii nang hfip phu cua bentonite No phu thugc vao lugng cation bu tri^r mang ludi Sd lugng cation cang Idn ihl kha nang trao dcii cang Idn Dung lugng cation dao dong lir 80 -^ 150 mgdl/lOOg Dung lugng trao ddi anion dao dong tu 15H-40mgdI/100g Ngoai ra, sir trao doi ion ciia bentonite lien quan den sir thay the cac nguyen lir hydro cac nhdm hydroxyl ciia montmorilonite Theo mot sd nghien ci'ru, dinh ciia cac tir dien Si04 hirdng phfa ngoai ciia Idp cfi'u true O dinh cac nguyen tir ciia oxy bi thay the bdi cae nhom hydroxyl va cac nhom dam nhiem viec tri lien ket yeu giua Ciic Idp va gop phfin vao su can bang dien ti'ch Trong montmorilonite co cac nhdm hydroxyl nfim d dinh ciia cac bat dien AlO^ Trong sau dinh ciia bat dien co hai dinh la nhom OH cdn bdn dinh la oxy( hinh3) OH OH / 0 I I I I Al \ 0 I' II H d 1 6^-A/ in / \ ? f Hinh Vi ni ciiu ciic nlioni OH c6 rroiii; maii;.^ luai can Hue ciia l)eiiionlfe Trong dd nhdm hydroxyl ciia lien ket Si-OH (1) kh6ng co kha nang trao doi hydro, nhdm hydroxyl lien ket Al - 0H(11) cd tfnh axit yeu nen kha nang trao doi yeu Nhdm hydroxyl lien le't Si-0-Al(l 11) cd tfnh trao ddi manh nen cd tfnh quyet dinh den dung tfch trao doi cation H"' 1.3.2 Bien tinh ldm bien ddi cdu triic Idp aluniinosilicat Khoang bentonite tu nhien chi'ra nhieu tap chat nhu cac mudi can xii (CaCOO, dolomit (MgC03), mot sd oxyt: FcjO^ , FeO, Ti02, v.v va cac tap chat khac Qua trinh hoat hoa bentonite dugc thuc hien bang each dimg kiem hoac axit hoa tan mot sd oxyt luang tfnh nhu AI2O3, Fe203, de tao tren be mat set nhung 16 xdp va trung tam hoat dong, Viec sir dung nong kiem hoac axft cao cd kha nang hoa tan nh6m oxyt lam thay doi cau true bentonite 1.4 Dac tinh cau true bentonite va kha nang hap phu Chfnh V] bentonite co ca'u tnic Idp va phan tan cao nen no cd cfiu true xdp phuc tap va be mat rieng Idn Ca'u tnic xdp anh hudng rat Idn de'n tfnh cha't hap phu ciia cac cha't, dac iiung ciia nd la tfnh chat chon loc chat bi hfip phu Chl co phan tir nao cd dudng kfnh dii nhd so vdi 16 xdp thi mdi chui vao dugc de tham gia va qua trinh ha'p phu Dua vao dieu ngudi ta cd the tien hanh hoat hoa cho co the diing bentonite lam vat lieu tach chat Day cung la diem khac giua bentonite va cac chat ha'ji phu khac Nhd du dicn tfch tren cac nguyen tir ciia cac nut mang tinh the eho nen bentonite la mot chat hfi'p phu phan cue va vl vay no se uu tien hfip phu cac chat phan cue Tuy nhien, bentonite van cd the hap phu cac chat khong phan cue lire van der Walls va tuang tac hfip phu chii ye'u la tuang tac cam ung Be mat bentonite eo dien tfch tuong ddi Idn bao gdm be mat ngoai va be mat Be mat bao g6in be mat ciia cac lap nhom silicat chdng len va dugc ngan each bang cac cation kim loai den bu dien tfch tren be mat Idp bentonite Be mat ngoai dugc xac dinh bdi be mat ciia cac mao quan chuyen tiep Cac mao quan dugc lao nen su tiep xiic ciia cac hat bentonite va cd kfch thudc khoang 40 A -^ 90 A Dien tfch ciia be mat ngoai phu thugc vao kfch thudc cac hat bentonite, hat cang nhd thi dien tfch be mat ngoai cang Idn Kha nang trao ddi ion Idn cung vdi kha nang hfip phu tdt ma ta cd mgl loai vat lieu xir ly kim loai nang ra't hieu qua tir bentonite II NHUNG UNG DUNG CHU YEU CUA BENTONITE Do cd kha lulng hfip phu lot nhieu cha't v6 co va hiru co, nen bentonite cd nhieu Uim dung kha da dang va phong phii sir phat trien ciia xa hgi 2.1 Sudung bentonite lam chfit hap phu K E T LUAN Da xac dinh dugc didu kien tdi uu cho quii trinh hfip phu null sd ion kim loai naiig (Mir'' vii Fe-"") moi tnrdng nudc ciia bentonite kidm thd Di Lmh - Lam Ddng: pH = 4,0; thdi giiin tiep khufiy iron: 2h da khiio sat quii trinh lam giau benlonite Di Linh - Lam [3dng biing qu\ trinh thfch hgp ke'l hgp giua king giin va thuy xyclon Ket quii dii lulng dirge hiim lugng ciui montmorillonite bentonite iir 40-45% len - % , hieu suill thu hdi diit - % Da khao siit qiui irlnh hoiil hoii bentonite sau da lam giiiu ddi voi bentonile Di Linh Lam Ddng va Xiic dinh dugc didu kien thfch hgp cho qiui tiinh hoiit hoa lii: ndng axil II2SO4 15%, nhiet hoiU luxi: 90"C, thdi gian hoiit hoii: 6h ly le khdi hrgng R/L la 1:3, dieu kicn co khufiy iron miinh Sau dugc hoiil hoii tiong didu kien da neu d tren, ty lc giua Si02/Al20, diit 3,65, ham lugng Ciic oxit kim loiii kiem thd cdn liii thfip (hiim lugng Ciin.xi giam - Ifin, hiim lugng nuigie giiim luii kin), then ifch be mat rieng diit kha tdn (114 n r / g ) , hfip dung ddi vdi Ciic ion kim loiii nfmg ulng khii ciio: hfip dung ddi vdi Mir^ lang 1,71 kin, lulp dung ddi vdi Y-e'^ tang 1,47 Ifin, hiim lugng bcntonie tfmg len >1{)% Bentonite sau dugc kim giiiu vii hoitt hoii diip ling dugc _\eii cau ciia nhieu hnh vuc ung dung cd ITnh vuc xir If moi truong rai lieu tham khiio / O Abollino et al Adsorption pH a/ul organoic substances R Nassem using bemonde of heavy metals on Na - mojmnorillonite I Water Research 37 (2003) 1619 - 1627 and S S Tahir Removal of Pb(ll) f'om as an adsorbcm Vol 35, No 16, pp, .lung Ju Lee a al Simultaneous organohentomte I Chemosphere Sanu'cr Al- Asheh different tvpes of activated Fffcct of 49(2002) FawziBan!, bentonite sorption aqueous acidic solutions by 3982-39S6.2(hd of lead a^^J clorobenzence by 1309-1315 Leena Abu-ailh Saparation and Adsorption of phenol Purij:, uiion using Techonology, 33{2()03)I-I0 A.G Lspa!aleon,./ the removal A Nido, M Fernadez A Marsal L s if activated clays in of dves and surf tctants from tannerv waste waters Applied x.vi2003}.vv\-.\xx M Bacquet et Adsorption Letters.vd 2003 of poly(4-vinylpyruhnc) Clay imo ocntomtes Science Materials }.\xx.\xx 10 B Koumanova, P Peeva-Antova A of P-chlorophenol jnjni aqueous solutions on bentonite and perl ite Journal of Hazardous Materials A90 (2002)229-234 W P Gates, J S Anderson, M D Raven, G J Churchman Mineralogy of a bentonite from Miles, Queensland, Australia and characterisation of its acid activation products Applied Clay Science 20(2002)189-197 Allen Adrian Swingburn, Stckwell John Oliver, Black lan James Activation of Swelling Clays US Patent, number USJ9980I42220 J998J006, date 2000-02-15 10 Helena Paczek, Jcrzy Harasowski Method of activatim^ bentonite clav US Patent, number US32406I6, date 1966-03-15 Cong Irlnh nghien ciiii niiy dugc thuc hien vdi sir ket hgp giua cac can bg bg mon Hoa V6 CO - Khoa Hoii hgc - Trudng diii hgc Khoa hgc Tu nhien - DHQG Ha Ngi va cac can bg Vien Cdng nghe Xii Flicm - Vien Nang hrgng Nguyen tir Viel N;im Phfin cong viec lily mau nghien cuu, khito siit giai doiin lam giau va hoiit hoa khoiing bentonite dugc thuc hien chii yeu d Vien Cong nghe Xii Hiem - Vien Nang lugng Nguyen tir Viet Nam, phfin nghien cii'ii hoiil hoa quang va khiio siit khii nang hfip thu ducy llurc hien chu yeu d phdng thf nghiem Vfit lieu mdi, Bo mon Hoii Vo co - Khoii Moa hgc - Tiiriyng diii hgc Khoa hgc Tir nhien - DHQG lla Ngi C6ng trinh dirge DHQG lla Noi cil'p kinh phf Chiing loi xin chan ciim on lanh diio DHQG Hii Noi dii cfip kinh phf de cluing toi cd the thuc hoien dugc cac ngi dung nghien ciiu tren 11 y •••-' m THU HOI URANI VA MOT SO KIM LOAI NANG TIT DUNG DICH BANG PHU^ONG PHAP HAP PHU TREN BENTONITE (Removal of Uranium and heavy metals from aqueous solution by using bentonite as an adsorbent) il' THAN VAN LIEN', D QUt SON', CAO HUNG THAI", DOAN THI MO', HOANG RICH '"' NGOC|, TRAN VAN SON', LE THI KIM DUNG', NGUYEN DINH VAN', NGUYEN THI HONG HA',NGO SY L U O N G ' , PHAM TRUNG TINH', VUONG VAN T R U O N G ' (!) Vien Cdng nghe xg tiiem (2) Trudng Dgi hgc khoa hgc tu nhien Dia chi lien he: Vien Cong nghe xg lue'm, 48 Lang Ha, Ddng Da, Ha Noi Dien thoai: CQ 8353181 ' NR: 8584495 ' DD : 0912613087 Email: tvlien(S)hn.vnn.vn Astract - The sorption of U and hea\7 metals (Pb, Cr, Cd, Cu, ^^n, Fe and Zn) on Di Linh - Lam Dong benlonite ores at different condition of shaking lime, pH of solution , concentration, amour of adsorbent, was determined Isoiherm anlysis of adsorption data showed that the adsorption pattern of uranium and heavy metals on bentonite followed the langmuir isotherm and freundlich isotherm The adsorption of U, Pb, Cr, Cd, Cu, Mn, Fe and Zn on bentonite depends on many factors, for solution of low concentration of metals, the sorption capacity of bentonite are from 15 to 40 mg/g bentonile The sorption capacity of Di Linh bentonite increase in the folowing order: Pb^'< Cd-*< Cu-*< Zn^*< Fe^"'< Mn^* < Cr^'' < UO 2^* The avaluation of the total capacity of treated Di Linh - Lam Dong benlonite i, shews that this clay is a good sorbent towards all examined metals So that Di Linh bentonite may be used for :•- treatment uranium and heavy metals from liquid waste Keywords: Uranium; radioactive maierial; clay mineral; adsorbents; sorption; ion exchange; adsorpiion; bentonite: montmorillonite clay; lieavy metals M6 DAU: Bentonite la loai khoang set ton tai tir nhien, co cau true Icfp, co dien tfch ba mat Idn, CO kha nang trao doi ion cao va co kha nang lam thay doi hanh vi luu bien cua cac chat long mot each manh me, cho nen bentonite duoc uug dung rpng rai cong nghiep, ndng nghiep, y hoc, nganh nang lucmg nguyen tir va nganh che tao vat lieu mdi co kfch thuac nano ^: Bentonite duac ling dung de xir ly nudc co chu'a cac nguy6n id phong xa dac biet la nuoc thai 'sau qua trinh 15, Hien cac nghien cuu ve kha nang sir dung Na - bentomte dang nen lam vat lieu la'p cac kho chua chat thai phong xa dang dugc tien hanh NhCrng tfnh chat thfch ung cho ung dung la din thuy luc cua set bentonite da duoc nen rat thap (giu cho chi tu cac thai phong xa khdng nhiem vao nudc'ng^m) va nang suat trao d6i cation (de bat giu tat ca cac nuclit phong thoat tiir cac cha't thai phong xa) cao ^ , - ' , , , , Nhirng nam g^n day bentonite dugc img dung de che tao vat heu co kich thuoc nano Vat lieu co tfnh nang uu viet, dugc ung dung vko nhimg linh vuc, thi du: o ky thuat bao bi, ky Ihuat y 16, a c6ng nghe to, , ^ ^ - - x ^^ - ^ Theo ket qua dieu tra cho thay nirdc ta co tai nguyen bentonite tuong doi Ion VI vay, de gop phan dua bentonite nudc vao ung dung thuc te, nhung nam w a qua tai Vien Cong none xa hie'm da tien hanh nghien cuu nang cao ham luang bentomte va cong nghe hoat hoa bentomte nghian cuu danh gia kha nang hap phu uram va mot so kim loai nang iren bentomte, vv Tron2 khuon kh6 bao cao nav chiing toi xin gioi ihieu ket qua nghien cuu kha nSng hap phu'urani vhm6l s6 kim loai nang rren bentonite Di Linh - Lam Dong a dang tu nhien va dang da cua xir If I THl/C NGHIEM C6 loai bentonile dugc sir dting de nghien eu'u, la bentonite tu nhien la'y tir mo Di Linh, Lam Dong va loai bentonite Di Linh da dugc lam giau va boat hoa tai Vien Cong nghe xa hiem Bentonite tu nhien co ham lugng monlromorillonite la 48,0% bentonite sau da lam giau va hoat hoa co ham lugng montromorillonite Idn han 70% Kfch thu6c hat bentonite < 150 micron Cach tien hanh thf nghiem xac dinh hap dung kim loai nang tren bentonite: Chuan bi dung dich urani va dung dich kim loai nang v6i nong nhat djnh De dieu chinh d6 pH ciia dung dich da sir dyng dung dich dem axetat natri (de' dieu chinh pH irong khoang 2,5-5,5) va sir dung NaOH de dieu chinh dp pH khoang 5,5 den 8,0 La'y 500 ml cac dung dich cho vao cac coc Hit, cho vao 10 g bentonit, dat len may lac vdi toe dp 140 vong/ phut Sau hap phu bao hoa, lay 60 ml dung dich lpc va tia'n hanh xac dinh n6ng dp cac ion dich Ipc N6ng dp cua cac kim loai nang dirge xac dinh tren may ICP hoac bang phuang phap quang, dp pH dung dich dirge xac dinh bing may pH Trudc lilc tien hanh m6i mot thf nghiem set bentonile dirge dieu chinh de'n d6 pH tuang ttJ nhu d6 pH lam viec ciia dung dich dem Lugng ion kim loai hap phu bai bentonite (mg/g bentonite) dugc xac dinh tir sir chdnh lech nong dp kim loai dung dich trade va sau hap phu Dung lirang hap phu duoc tfnh theo cong thirc sau: a = [ ( C o - C ) V]/m Trong do: a la dung luang hap phu ciia bentonite; CQ la nong dp ion kim loai dung dich dau; C la n6ng dp ion kim loai can bing duac thiet lap; m la khoi lugng bentonile diJng de' ha'p phu; V la the tfch dung dich kim loai n KET QUA VA THAO LUAN 2.7 Xdc dinh th&i gian dat cdn bang hdp phu De xac dinh thcd gian dat can bing hap phu, da tien hanh thf nghiem xac dinh sir phu lhuoc cua luong kim loai Fe^\ Mn'", P b ' \ Cu'\ Cd'\ Zn'\ Mn'\ Cr^\ F e ' \ UO'^^ duoc h&'p phu vao thai gian vdi dung dich cac kim loai c6 n6ng d6 0,1 - 4,0 g/1 Ke't qua cho thay gia ha'p phu diu lien, tang lh5i gian hap phii lirong kim loai duac ha'p phu tren bentonite ciing tang ian va dat 95-99% tai then diem gid Sau gid ha'p phu, na'u cu tia'p tuc tang thdi gian ha'p phu thi lugng kim loai dirge ha'p phac tren bentonite vin kh6ng tang nghla la da dat can bing ha'p phu Vi vay, cac thf nghiem de' xac dinh hap dung tia'p theo dugc tie'n hanh vdi thdi gian hap phu la gid 2.2 Anh hudng cua pH den hdp 120 ^-•ii^ dung kim logi ndng tren bentonite: Ka't -Cr 100 qua khao sat anh huong cua pH (trong -Mn khoang 2,5-8,0) den ha'p dung kim loai 80 Zn nang tren bentonite dugc chi a hinh I -Cd Ke't qua cho thay ring dp pH giam thi •5 60 Pb ha'p dung cung giam Su anh huang the I hien ra't ro ddi vdi cac ion kim loai Cu, Pb i 40 -Cu' va Cd, d6'i vdi cac kim loai khac anh huong t miic dp tha'p ban Dp pH anh hudng khac =,' 20 -u da'n su hap phu cua timg ion va irong khoang pH < 3,5 thi hap thu tang lan theo 10 lhu- tu sau: Cu'-^ < Pb'" < Cd'^ < Zn'" < pH Mn'" < Cr'"