Một số yếu tố ảnh hưởng đến hiệu quả xử lý DDT tồn lưu trong môi trường đất và nước bằng sắt Nano

KHOA HQC C 6 N 0 NOH^<br /> <br /> <br /> <br /> MOT SO Y £ U T O AlXlH HLTQIMG D £ I V H I $ U Q U A X U LY<br /> DDT TOIXl L U U TROIVG IVIOI TRUdlVG D A T V A IVUOC<br /> D A I V G S A T [XIAIVO<br /> U Dlic^ NguyfinXuin Huin*, LftTliiThiiyAii',<br /> Ph^m TTii Thiiy Duong*, Die Thi Um'. Tt4n Thi Tliiiy'<br /> <br /> T6MTAT<br /> DDT li loai thu6c trir siu trude kia duijnc su dgng ph(J bidn M tidu didt cic loai cdn tning. Do tinh ddc h^<br /> cao, thdi gian tdn tgi trong mdi trudng dii ndn hidn nay da bj c ^ sir dgng. Tuy nhidn, lucmg DDT tdn luu<br /> trong mdi trudng di(t vi nude d cic kho chua hidn dang gSy nhftng tic h?! Idn ddi vdi con ngudi. Nghidn ^<br /> ciiu niy xic djnh mdt sd ydu td inh hudng dffn hidu qui xii ly DDT bilng v$t lid" Fe" nano. Kdt qua nghidn<br /> cdu cho thfly, s^t nano cd hidu qui xii ly DDT cao, tuy nhidn hidu qOa xii ly niy phy thudc vio m^t s6 ydu<br /> td. Khi xu ly nude 6 nhi^m d ndng dd 35 mg/1, ty Id sit nano/DDT li 19/1, pH - 3, thi sau 24 gid, hidu<br /> qua xu ly d^it 82,51%. Khi pH tilng Idn 7 hidu qui xii \y giim chi cdn 69,74%. Ddi vdi d^t d Huong Vin, Tidn<br /> Du, Bic Ninh cd him lu9ng DDT li 0,978 mg/ kg, khiti1$ sit nano/DDT li 205/1 thi sau 10 ngiy, toin bO<br /> lugng DDT Uong dit da dupe xii ly hdt, vdi ty Id sit nano/DDT li 4/1 thi sau 20 ngiy cdtii^xu ly du^ic 7896.<br /> T^i pH = 3, hidu qui xir ly DDT li cao nhit (79,33% sau 20 ngiy), sau d6 giim din khi ting pH Idn 5 vi 7.<br /> Hidu qui xu l^ DDT bdi sit nano cung bj inh hudng ciia axit humic. Hidu qui xii ly giim tu 78% xudng cdn<br /> 20% khi bo sung thdm 50% lupng axit humic so vdi luong axit ban diu vio dit nghidn ctiu.<br /> T^j khda: Anh hudng, DDT, mdi trudng, sit nano, xCrly.<br /> <br /> PAA. Hat sit nano di^u ch^ dugc cd kich thudc tuong<br /> ddi nhd (10 - 18,6 nm), cd di^n tich bd mat Idn (60<br /> 6 nhidm hda ch^t bio vd thi^ vit ton luu trong<br /> mVg) dupe lim khd v i bao quan or nhidt dd phdng<br /> mdi tnrdng do cac kho chua d^ lai trdn dia ban c i<br /> [1].<br /> nude da giy anh huong nghidm trpng ddn chat lugrng<br /> moi trudng dong thdi cung gay anh hudng khdng - Mhi nude dupe giy nhi^m DDT nhin t^o.<br /> nhd tdi siic khoe cua nhin din trong khu vuc. Vi v$y, - M5u d^t dugc ISiy t^i thdn Lac V$, xi Huong<br /> ngiy 21 thing 10 nim 2010, Thu tudng Chinh phu da van, Tidn Du, Bic Ninh. Diy l i di^m giy biic xiic v^<br /> ban hinh Quy^t dinh sd 1946/QD-TTG v^ k^ ho^ch d nhidm mdi trudng cho nhin din d trong vung.<br /> xii ly, phdng ngiia d nhidm mdi truong do hda ch^t<br /> - Axit humic dugc tich ra tu than birn theo<br /> bao vd thuc vat tdn luu trong ph^un vi ca nude. Hidn<br /> phuong phip ci'ia Jononova- Bentricova.<br /> nay phuong phip xu ly chu y^u l i thidu huy, chdn<br /> l^p, cich ly, sir dung vi sinh ho$c hda chit k^t hpp b. N0i dung viphinmgphup nghiin oiu<br /> vdi chdn l^p. Vide nghidn ciiu cdng nghd sit nano d^ + Khao sit khn ning x r ly cua Fe"nano vdi nuoc<br /> xii ly cic ch^t thii ddc hai, cic chit thii nguy hai d i b( giy nhi^p. ODT nhan tao.<br /> dupe nhi^u nude lira chpn. Tinh ridng b My, nim<br /> - Khio sit anh hirnnp cua thdi gian defn hidu qua<br /> 2001 da cd hon 20 dv i n dupe hoin thinh. Nghidn<br /> x u I y D D T m „nudc:<br /> ctiu niy d^ cip d^n mdt sd y^u td i n h hudng d^n<br /> hi$u qua xii ly DDT tdn luu trong d^t v i nude b ^ Hda tan DDT vio dung djch etanol: nude vdi tj<br /> sit nano. le 1:10, dung dung djch d^m CH3COONH4 dik<br /> chinh dung dich vd pH = 3, sau khi tan dinh miic de<br /> I . Ddi TUQK, NOI IHinK VJi PHUOW PIW NGHEN Ciiu dugc dung djch cd ndng dO DDT la 35 mg/1. Lay 8<br /> a. Ddi tupng nghidn cihi binh tam giic 100 ml chia d^u thinh 2 nhdm va hiit<br /> vio mdi binh 15 ml dung djch trdn. Cin chinh xic<br /> - Sit nano do nhdm nghidn ciiu di^u ch^ bing<br /> 0,01 g Fe° nano cho vio 4 binh tam giic nhdm 1. Cac<br /> each su diing phuong phip khu mudi sit pha trong<br /> binh tam giic cdn lai khdng cho Fe° nano d^ lim doi<br /> con b ^ g NaBHj khi cd su dimg chit phin t i n l i<br /> ehiing. Sau thdi gian 3 gidf, 10 gicr, 17 gid, 24 gio.<br /> phin tich lupng DDT cdn 1^ trong cic dung djch {ca<br /> ' Khoa Mdi trudng, Tmdng D^i h^c Khoa hpc T\r nhidn<br /> <br /> 40<br /> N O N G NGHllP VA PHAT TRIEN N O N G T H C N - K i 1 - THANG 6/2012<br />  KHOA Hpc C 6 M G N G H |<br /> <br /> <br /> nku cd Fe" nano vi mau ddi chiing) b ^ g phuong D^t nghidn ciiu dugc thay ddi him lugng axit<br /> Dhip phin tich sic ky khi [2]. humic bing .cich bd sung thdm axit humic vdi lugng<br /> - Khao sit anh hudng ciia pH dung djch d^n hidu 50,100,200 vi 400% so vdi lupng axit humic ban diu.<br /> ^ui xu ly DDT trong nude: Sau dd cin cii vio k^t qui khao sit inh hudng ciia<br /> him lupng Fe'* nano (tiii nghidm 3) d^ lira chpn him<br /> Hda tan DDT vao dung dich etanol: nude vdi ty<br /> lupng Fe" nano cintiii^tdua vio d^t. Cin cii vio kdt<br /> id 1:10, diing cic dung djch ddm CHgCOONHiCd pH<br /> qui khio sit inh hudng ciia thdi gian (thi nghidm 1)<br /> = 3, 5 vi 7 d6 didu chinh dung djch trdn v^ pH - 3, 5<br /> d^ li^a chpn thdi di^m l^y miu vi phin tich lai him<br /> vk 7, sau khi tan djnh miic d^ dupe cic dung djch cd<br /> lugng DDT cdn lai bing phuong phip sic ky khi [2].<br /> ndng dp DDT li 35 mg/1. Uy 6 binh tam giic 100ml<br /> chia d^u thinh 2 nhdm vi hiit vio m6i binh 15 ml • . K ^ QUA niGHEiv CUU vA THAO LUAN<br /> dung dich trdn. Cin chinh xic 0,01 g Fe^nano (tuong 1. Mdt sd tinh ch^t ca bin ciia m^u dit nghidn<br /> ling vdi ty Id Fe"* nano/DDT li 19/1) cho vio 3 binh cihi<br /> tam giic nhdm 1. Cic binh tam giic cdn 1^1 khdng<br /> Xu ly d nhi^m DDTti-ongd^t bing Fe"* nano<br /> cho Fe" nano d^ lim ddi chiing. Sau thdi gian 17 gid,<br /> ehju inh hudng rit nhi^u cua tinh ch^t ca ban cua<br /> phin tich lugng DDT cdn lai trong cic dung djch (ci<br /> miu d^t nghidn ciiu. Vi v|iy, di phin tich mdt sd tinh<br /> mSu cd Fe" nano vi miu ddi chiing bing phuong<br /> ch^t ca bin ciia d^t theo cic phuong phip thudng<br /> phip phin tich sic 1^ khi [2].<br /> diing trong phin tich dit K^t qui nghidn ciiu dupe<br /> + Khao sit mot so y^u td anh hudng tdi khi ning th^ hidn d bing 1.<br /> xu if DDT trong d^t bdi Fe" nano.<br /> Bing 1. K^t qui philn tich mft s6 tinh chdt ccrbiln<br /> - Anh hudng ciia thdi gian tdi hidu qua xii ly: cua miu ddt nghito cihi<br /> Cd dinh him lupng Fe° nano trong miu xtr ly, TT Thdng s^ phin tich (don vj)<br /> Ditninkho<br /> thu nghidm hidu qua xii ly ciia Fe° nano theo thdi Huong Vin<br /> gian: 5 ngiy, 10 ngiy, 15 ngiy, 20 ngay. M^u d^t sau 1 PHKQ 3,46<br /> khi xii If dupe phin tich xic dinh ham lupng DDT 2 Chit huu ca(%) 1,79<br /> bing phuong phip phan tich sic ky khi [2].<br /> Cit {%) 71,32<br /> - Anh hudng cua him lupng Fe" nano tdi hidu Thinh phin<br /> 3 limon (%) 10,41<br /> qui xu ly DDT trong dat: cagidi<br /> Set 06) 18,27<br /> Ham lupng Fe" nano dupe dua vio xahi nghidn 4 CECCmgdl/lOOgdit) 6,28<br /> ciiu sao cho ty Id ciia Fe" nano/DDT li 0 (ddi chting,<br /> khdng b6 sung Fe" nano), 2, 4, 8 vi 12 lin. Cin cii 5 Axit humic (%) 0,080<br /> vao k^t qua khao sat anh hudng ctia thdi gian (dii 6 NOaOng/lOOg) 3,372<br /> Qghidm 1) de lua chpn thdi di^m l^y mSu vi phin 7 PiOsTsW 0,057<br /> tich lai him lugng DDT cdn Igi bing phuong phip 8 P^OsaCmg/lOOg) 0,243<br /> sic ky khi [2]. 9 Fe^*(mg/100g) 0,95<br /> - Anh hudng cua pH dat tdi hi^u qua xu ly: 10 A1A») 1,95<br /> Cic miu nghidn ciiu dupe thay ddi pH d^t tgi 11 Fe^OsCSl) 1,68<br /> cic gii tri 3, 5 vi 7. D^t sau khi diay d6i gii tr; pH 12 DDT(mg/kg) 0,978<br /> 3upc d^ trong di^u kidn tu nhidn trong 7 ngiy. Sau<br /> 4d cin cii vio k^t qua khao sit anh hudng cua him K^t qui phin tich cho thf(y, d^t nghidn oiu cd<br /> I'rang Fe° nano (thi nghidm 2) d^ lua chgn him gii tri pH = 3,46 d miic rat chua, him lupng ch^t hiiu<br /> ca li 1,79%, d miic nghdo; thinh phin ca gidi thudc<br /> lugng Fe° nano can thiet dua vio d^t Cin eii vi k^t<br /> iogi d^t thit pha cat CEC d miie th^; him lugng<br /> lui khao sat anh hudng ciia thdi gian (thi nghidm 1)<br /> 3^ lua chgn thdi di^m lay miu vi phin tich lai himDDT li 0,978 mg/kg.<br /> ugng DDT cdn lai bing phirong phip sic ky khi [21. 2. Khio sit khi ning xii ^ ciia Fe** nano vdi nude<br /> - Anh huong cua ham lupng axit humic tdi hidu bi giy nbiSm DDT nhin t^o<br /> luixuljh a. Anh huong cOa thdi gian ddn hiiu guixuiy<br /> <br /> "JdNG NGHllP VA PHAT TRIEN N O N G THdN - ICV' 1 - THANG 6/2012 41<br />  KHOA HpC C 6 N 0 NOHt<br /> <br /> 30 - Khu boi hidro: H, li sin pham cua qua trinh an<br /> >• to m6n trong diiu Itijn ky khi c6 th^ phan ling voi RX<br /> <br /> <br /> LX<br /> J)<br /> ^ n n^u c6 tic dOng ctia chit xuc tic.<br /> fa) • Fe» + HjO -» Fe^- + OH + H, (4)<br /> <br /> <br /> <br /> <br /> 1 Jj •<br /> •I H, + I « •> RH+C1+H'(5)<br /> |io<br /> <br /> Klui tntc tiep tren b^ 11)41 kiiii loai<br /> <br /> S«]k SHlOh So I l k S»]lh<br /> <br /> TUipulttlf<br /> <br /> <br /> <br /> Hinh 1. N6ng dO DDT c6n lai vi hi^u qui xiH)> DDT<br /> theo th6i gian<br /> | - * - N i n 9 dS Felll), mgfl - • - M i f i g « Fe(lll), mi^ \<br /> <br /> <br /> <br /> ,„^' "<br /> p<br /> £<br /> 3»<br /> 300<br /> ^<br /> s ^ ^<br /> y<br /> ^<br /> " " ^ a —<br /> D<br /> Sa3h StuIDh StnlTh SIU 34k<br /> <br /> Tboigiu^ly<br /> ^CJ Kh«trvcliepbdiH;\mvaitr6cuacliaixuclae<br /> Hinh 2. Ndng dd Fe^ vi Fe** sau xii ly DDT bing<br /> Fe" nano<br /> Ket qui nghidn oiu cho thay, trong didu kidn<br /> khdng bi inh hudng bdi cac y^u to khac thi kha ning<br /> xu ly DDT ciia Fe° nano li rat nhanh. Ca che ciia qui<br /> trinh xu ly nay dugc Paul Tratnyek vi Matheson<br /> nghidn ciiu vao nim 1994 [3], la ca ch^ khu mgnh<br /> RX<br /> <br /> <br /> <br /> HH + C I - + H *<br /> C<br /> ciia Fe" nano. Tuy nhidn, hidn tugng in mdn sit kim<br /> Nguyen l^ phin ung cua F^ nano vdi hpp diit<br /> loai tao ra ion sit vi H2, ca hai san phdm nay cung<br /> hau CO chua do theo Tratnyek va Matheson (1994)<br /> ddu cd khi ning tham gia phan ling khii, tuy thudc<br /> vio chat d nhidm. Paul Tratnyek vi Matheson di dua 6 moi trudng axit, Fe" ddng vai trd li chit khii,<br /> ra 3 phuong thuc khu ciia Fe° nano dupe trinh biy cho electron.<br /> dudi diy: Fe^^Fe^* +2e(l)<br /> - Khit true ti^p tai b^ m|lt kim loai: Dd li su RCl + H* + 2e->RH+Cl(2)<br /> chuyen nhupng electron tryc ti^p ciia Fe" nano cho Tdng hgp cua hai phin ling 1 vi 2 li:<br /> cac hidroncacbon halogen (RX) hip phu trdn b6 m$t RCl + Fe'* + H* -• RH + Fe^* + CI" (3)<br /> ciia hd kim loai- nude, k^t qui li phin ling khii cio vi Vi du: CjCl^ + 5 Fe" + 6H* -> C^YU + 5Fe=^ + ^^<br /> san ph&i Fe(II) dupe tao thinh.<br /> Nhu vay, Fe" nano cd kha ning khu dugc nhi^<br /> Fe"+ RX + H* -> RH + X- + Fe^* (1) hgp chit huu ca chiia cio. Sau 24 gio xu ly, nong ^9<br /> - Khu bai FeOD h-dn b^ mit: FeOD li san phim DDT di giam bJ 35 mg/1 xudng cdn 5,57 mg/1, hifiu<br /> cua qui trinh in mdn Fe" ciing cd Ih^ tham gia phan qui xu ly dat 84,1%. N6ng dO DDT giam theo thoi<br /> jng khtr cio trong RX, tao thinh FeGIO- gian phan ling, thdi gian cing lau thi lugng DDT cin<br /> Fe^+RX + H* -> Fe3*+RH + Cl-{2) lai cing thip. Trung binh sau 1 gid thi lupng DDT<br /> Fe^* + H2O -> Fe='*+ Hj + OH' (3) khu dugc li 1,23 mg/1, tuy nhidn tdc dd khu li khflng<br /> <br /> 42 NONG NGHIEP VA PHAT TRIEN N 6 N G T H O N - ICV' 1 - THANG 6/2012<br />  KHOA HOC GONG NGHl<br /> <br /> <br /> giong nhau b m6i giai doan. Trong 3 gia dau ( 0 - 3 24 gib. Di^u niy co th^ la do luong Fe° giim xuong<br /> gio) luong DDT bi khii la 9,54 mg/1 tuong duong theo thoi gian, mot phin bi oxi hoa thinh Fe(II),<br /> 3,18 mg/1 trong 1 gicr, 7 gio sau (3 gio • 10 gio) luqmg Fe (III). K^t qua phin tich ham luong Fe'* va Fe'* cua<br /> DDT bi khir li 11,16 mg/1 tuong duong 1,59 mg/1 cic dung djch sau xii ly DDT trong nude duoc thi<br /> trong 1 gio; sau 7 gia tiep theo (10 gia -17 gib) luong hi$n o hinh 2. Him lu(?ng Fe'* vi Fe** trong dung<br /> DDT bi khu l i 8,19 mg/1 tuong duong 1,17 mg/1 dich sau xir ly DDT dupe tao thinh va ting din dieo<br /> trong 1 gio; v i sau 7 gio ti^p theo (17 gio -24 gio) th6i gian xii ly. Him luong Fe'* vi Fe"* lin luot ting<br /> luong DDT bi khu l i 0,546 mg/1 tuong duong 0,078 tir 113 vi 10 mg/1 sau 3 h xii ly 14n d^n 460 vi 56<br /> mg/1 trong 1 gio. Nhu vay, trong giai doan diu tifen mg/1 sau 24 h xii ly,<br /> kha nang khii la nhanh nhat, sau do giam din o cic<br /> b. Anh huvng cua pH dung dich dSn hi^u quaxti<br /> giai doan sau vi giim manh nhat a giai doan tu 17 -<br /> ly<br /> Bang 2 Hi^u qui xu ly DDT bing Fe° nano tai cic pH khic nhau vi cic sin phim tnuig gian dupe tjio thinh<br /> pH Nom' d e DDT (mg/1) >16ng d6 DDD (mg/l N6ngdODDE(mE/l)<br /> TT Tnjoc Sau Truoc Sau Hi$u Truoc Sau Tnroc Sau<br /> xuly xiily xirly xiily qui, % xuly xiily xirly xirly<br /> 1 3 3.94 35 6,12 82,51 0 1,91 0 0,20<br /> 2 5 5,23 35 7,64 78.17 0 3,93 0 0,37<br /> 3 7 6,51 35 10,59 69,74 0 5,49 0 0,55<br /> Ket qui nghien ciiu d bang 2 cho thay tai pH = 3 va 0,37 mg/1; tai pH = 7 cic san pham trung gian la<br /> hidu qua xii ly DDT bang Fe" nano dat gii tri cao DDD vi DDE l i Idn nhat, tuong ling bing 5,49 vi<br /> nhat (82,51%), hidu qua xu ly giam xudng cdn 78,17% 0,55 mg/1. Qua dd cho thay, tdt nhat ndn xii ly DDT<br /> khi tang pH Idn 5 v i tiep tuc giam xudng cdn 69,74% tai pH = 3 vira cho hidu qua cao vi cic sin pham<br /> khi ting pH len 7. Tai pH = 3 va 5 (mdi trudng phan trung gian cung nhd. Trong khudn khd ciia nghidn<br /> ung la axit) thi gia tn pH sau xii ly tang tuong ling la ciiu niy chua xic dinh dugc cu thd san pham cua qui<br /> 3,94 va 5,23. Dieu nay cd the l i do trong mdi trudng trinh khii DDT tao ra. Tuy nhidn theo nghien ciru<br /> axit thi CO che khu DDT bdi Fe" nano dugc thuc hidn "khii cio trong thudc didt cd bing hot s i r ciia cac tie<br /> do qua trinh khii true tiep trdn bd mat kim loai va gii Angela Volpe, Antonio Lopez, Giuseppe Mascolo<br /> khii bdi ion Fe^'. Trong q u i trinh phan ling, theo hai vi Antonio Detomaso (2004) cho thay: ket qua cua<br /> CO che niy, can nhan them H" tir mdi trudng lim xiic qua trinh xu ly tiiallate (S-2,3,3-ti-ichloroallyl di-<br /> tic cho qua trinh khii ndn trong dung dich mat di isopropyl thiocarbamate) bing hot sat (20-50 fun) vdi<br /> mot phan H', lim cho gii tri pH cua dung dich ting dung dich tiiallate cd ndng dp 2,5 mg/1 chi ra rang,<br /> len. Ca ch^ phan ting dugc the hien d phuong trinh sau 5 ngiy thudc trir cd da giim tdi 97% va sin pham<br /> phan ling sau: chinh cua phan ling li alkyl da dupe khit cio (S-2-<br /> propyl di-isopropyl thiocarbamat). Tuy nhien, mdt<br /> RCl + Fe" + H* -J- RH + Fe^* + CV lupng v^t dichloroallyl di-isopropyl thiocarbamat<br /> Tai pH = 7 sau xu ly gii trj pH giim di cdn 6,51 cung dirpc phat hidn, dd cung chinh l i vai trd vi mat<br /> do ti-ong mdi trudng trung tinh d^n ki^m thi ca ch^ trii ciia qui trinh khii cio [4].<br /> khii DDT bang Fe" nano dupe thuc hien do q u i tiinh Theo Quensen, DDT, DDE v i DDD ti-ong h-am<br /> khii true tiep bdi Hg, sin pham sau phan ting cd tao tich vi trong dat cd k h i ning ehuydn hoa thinh<br /> thanh H'^ lim cho gii tri pH ciia dung dich sau phan DDMU Cl-cloro-2,2 bis[p