Quan ly Tai nguyen rimg & Mol tn/dng
/V NGHIEN Ciru KHA NANG HAP PHU THUOC NHUOM METHYLEN XANH CUA VAT LIEU HAP PHU CHE TAO
Ttr LOI NGO VA VO NGO
Duong Thi Bich Ngge', Nguyin Thi Mai LiroTig^, Nguyen Thi T h a n h ' ThS. Tru&ng Bai hQc Ldm nghiep
SV. K55 KHMT, Tru&ng Bgi hoc Ldm nghiip T O M T A T
Nghien citu tiin hknh thf nghiSm kha nang hap phu methylen xaiih ciia vit lieu hip phu (VLHP) duoc chfi tao til 1 g ISi ngo, 1 g v6 ngo trong cic diSu kien thay dfli ve thoi gian, pH va nflng dfl 6 nhiim methylen xanh Theo thoi gian, sau 20 phiit hi^u suit h ^ phu methylen xanh ciia 15i ngo va vo ngo da len toi gan 98%. Qua trinh hip phu methylen xanh diu dat tren 96% trong khoang pH rit rflng tir axft manh den ki€m manh: loi ngfl tir 3 dfln 11;
vfl ngfl tii 3 den 8,8. Kha nang hip phu ciia 16i ngo va vfl ngfl c6 xu huong giam nhe khi nflng do methylen xanh tang tir 200 mg/l dfln 350 mg/l nhung hieu suit vin dat treu 97%. Trong tit ca cac dieu kien thi nghiem ciia nghien ciin, l5i ngo lufln cho dung lucmg h ^ phu can biing cao hon gin 2 lan so vai vo ngfl. N ^ e n ciru d2 buac dau khang dinh VLHP tir I5i ngfl va vo ngfl, hai phfl pham nong nghiflp pho bifln 6 Viet Nam, co liflm nang rat ldn trong Xli ly fl nhiim niroc thai do thuflc nhuom methylen xanh.
Til khoi: Hdp phg, loi ngd, methylen xanh, phi ph&m ndng nghiip, vai lieu hip phu, vdngd
I. BAT VAN BE
6 nhiem mdi trudng do nuoc thii noi chung vi nudc thii det nhugm noi ridng l i mgt van dd mdi trudng "ndng" 6 Viet Nam trong nhiing nam gin diy. Nudc thai det nhugm thudng bi d nhiem mau do sir cd mat ham lugng ldn cac chat nhudm. Viec xir ly nuac thai ddt nhugm thudng gap nhieu khd khan do thudc nhugm cd tinh chit jat ben, ciu tao phuc tap din den chi phi xir ly thucmg rat cao. Do do nghien cuu de xu ly d nhidm do thudc nhu^m trong nuoc thii biing cic VLHP co gii thinh thip, thin thien vdi mdi trucmg nhu loi ngd va vd ngd la vide lam rat can thidt.
Methylen xanh la mdt loai thudc nhugm dugc su dung khi phd bidn trong cdng nghidp det nhudm, thudng dugc sir dung true tidp dd nhugm miu vai, sgi bdng hay diing d6 nhudm giiy; nhudm cac san phim tir tre mia, manh trie da va chd muc vidt. Methylen xanh co thd g i y ' r a cac benh vd mit, da, dudng hd hip, duang tieu hda v i tham chi giy ung thu. Ndng dd methylen xanh trong nudc qua cao se ciu trd SLT hip thu oxy vio nudc tir khdng khi do
dd lam cin trd su sinh trudng ciia cic ddng thuc vat, giy ra hien tugng xao tr0n hoat ddng ctia vi sinh vat va anh hudng den qui trinh tu lim sach ciia nuoc.
Nghien cuu tiinh bay khi nang xii ly methylen xanh nha qui trinh hip phu ciia hai VLHP dugc chd tao tir loi ngd va vd ngd trong cic didu kien thi nghiem khac nhau vd thoi gian hip phu, khoang pH va ndng dg d nhidm methylen xanh. Nghien cuu nhim tim kiem giii phap Xli ly thudc nhudm methylen xanh vol chi phi thip, khi thi v i than thidn vdi mdi trudng.
n . PHl/ONG PHAP NGHIEN ClTU 2.1. Phuong phap b6 tri thi nghiem 2.1.1 Vdt lieu nghiin ciru
• Ldi ngd: Ldi ngd dugc thu gom v i loai bd het cic tap c h i t sau do dugc nia sach bing nudc cit, tidp theo phoi loi ngd cho khd tir nhien; sau dd dem loi ngd di nghidn ca hat tir 0,1-0,4 mm v i siy khd bing tu siy 6 105°C trong 30 phiit.
• Vd ngd: Vd ngd dugc thu gom va loai bd TAP CHI KHOA HQC VA CONG NGHE LAM NGHIEP S 6 2 - 2013
Quan ly Tai nguyen rimg & Moi tn/dng hdt tap chit, rira sach bing nuac cat, phai vd ngd cho khd tu nhien; cat hoic nghidn vd ngd ddn kich thudc 0,2-0,5 mm, sau do siy khd trong tu siy d 1 OS'^C thdi gian 30 phiit.
2.1.2. Khd ndng hdp phu methylen xanh cua vd ngd vd ldi ngd iheo th&i gian
• Ldi ngd: Liy 5 binh ndn dung tich 50 ml chira 20 ml methylen xanh vdi ndng do 300 mg/l cd pH=7 v i tai nhiet do phong. Cin lg vit lidu cho vio mdi binh dung dich, lac trong cic khoing thdi gian khic nhau l i 20 phiit, 30 phiit, 40 phiit, 60 phiit, 80 phiiL Sau do lgc bd ba rin bing giiy lgc, giii lai dung djch sau khi lgc. Lay chinh xic 10ml dich lgc cho vao cic binh dinh miic 50 ml. Binh muc tdi vach bang nuoc cat va dem di so miu, thu dugc kdt qua ndng do methylen xanh trong dung dich sau hip phu.
• Vd ngd: Cich thuc hidn tuong tu nhu loi ngd nhung dimg methylen xanh ndng do 200 mg/l.
2.1.3 Khdo sdt dnh htr&ng cua pH din kha ndng hap phu methylen xanh cua ldi ngo vd vd ngd
• Loi ngd: Liy 4 binh ndn dung tich 50 ml chiia 20 ml methylen xanh ndng do 300 mg/l.
DCmg NaOH 2M va HCI IM dd tao mdi trudng cd ndng dg pH lin luat Ii: 3,L; 5,0; 8,8; 11,4.
Cho vio moi binh lg vat lieu, sau do khuiy trong 40 phiit d dieu kien nhiet dg phdng. Lgc bd ba rin bing giiy lgc, giu iai dung dich sau khi lgc. Liy chinh xac 10 ml dich lgc cho vao cic binh dinh miic 50 ml. Dinh miic tdi vach bing nuac cat v i dem di so mau. Thu dugc kdt qua ndng dp methylen xanh trong dung dich sau khi lgc.
• Vd ngd: Cich thuc hien tuong tu nhu loi ngd nhung dimg methylen xanh ndng do 200 mg/l.
2.1.4. Khdo sdt dnh hu&ng cda ndng do methylen xanh din khd ndng hdp phu methylen xanh cua ldi ngd vd vd ngo
• Ldi ngd: Liy 5 binh ndn dung tich 50 ml chiia 20 ml methylene xanh vai nong dg lan lugt li: 200; 250; 300; 350 mg/I; d cimg didu kidn mdi truong pH=7. Can Ig VLHP vao dung dich, khuiy cic binh trong khoang thoi gian h i p phu la 40phut. Lgc bd ba rin bing giiy Igc, giir Iai dung dich sau khi lgc. Liy chinh xac 10 ml djch Igc cho vao cic binh djnh miic 50 ml. Dinh muc toi vach bing nudfc cit va dem di di so miu. Thu dugc ket qui ndng do methylen xanh trong dung djch sau khi lgc.
• Vo ngd: Cich thuc hi&i tuong ty: nhu I3i ngd.
2.2. Phffcmg phap so mau
Duong chuin methylen xanh dugc xiy dung tii cac ndng dd 2; 4; 6; 8; 10; 12; 14 mg/l va tai budc sdng cue dai Xmax^ 664 nm bing may do quang UV-VIS. Sau dd ndng dg dung dich methylen xanh sau qui trinh hap phu dugc xic djnh nhd dugc chuin tren.
2.3. Phu-ong phap xu* ly so h | u
De so sanh kha nang hap phu cua ldi ngd va vd ngd, nghien ciiu sir dung hai cong thiic sau:
Hieu suit hip phu:
H = <100(%) Dung lugng h i p phu cin bang:
£o_ C F ( -
-)
(1)
(2) Tror^ dd: H: hieu suit h ^ phi^ (%); q: dimg lugr^ h i p phu can bing (mg/g); CQ: ndr^ dO dung djch ban diu (mg/l); Ccb: ndng dO dung djch dat cin bing h i p phu (mg/l); V: the tich dung dich chit bj h i p phu (1); m: khdi lugng VLHP(g).
HL Ktr QUA NGHIEN CUtJ VA THAO L U ^ 3.1. Kha nang hap phu methylen xanh ciia loi ago va v6 ngd theo thoi gian
Ket qua nghien ciiu inh huong ciia thdi gian toi k h i nang hip phu methylen xanh cua loi ngd v i vd ngd dugc trinh bay d bing 3.1.
78 T ^ CHI KHOA HOC VA CONG N G H ? LAM NGHIEP SQ 2 - 2013
Quan ly Tai nguyen rimg & Mol tn/dng Bang 3.1. Th&i gian vd khd ndng h&p phu ngiu hon vd ngd. Dieu nay cd the giii thich l i
methylen xanh cda ldi ngo vd vo ngo do ham lugng chit xo cua loi ngd cao hon cua Thai Loi ngQ Vo ago vd ngd (gan 30%) va ham Iugng mo ciia loi g'^*i — g = ~ ngd thip hon vd ngd nen khi tidp xuc voi ldi (phut) (%) (mo/o) (%) (mg/g) ^S° ^^ thucmg thiy hk mat ciia loi ngd thd rap, san siii hon so vai vd ngd, do dd dien tich tiep 20
30 40 60 80
97,8 98,1 98,4 99,2 99,2
5,842 5,854 5,877 5,920 5,924
97,6 99,0 98,8 99,3 99,5
3,902 3,950 3,950 3,947 3,963
Xiic bd mat ciia loi ngd se ldn hon vd ngd. Day l i mdt trong nhirng nhin td din den khi nang hip phu ciia loi ngd ldn hon vd ngd.
32. Ajoh hirdng cua pH toi kha n a i ^ hap phu methylen xanh ciia loi i ^ va vd ngo
Mdi trudng pH co anh hudng den ciu tnic Ket qua nghidn ciiu cho thiy hieu suit hip bd mat ciia VLHP ndn cd thd inh hudng den phu H (%) cua c i hai VLHP ddu rit cao va xap kha nang hip phu methylen xanh ciia VLHP la xi trdn 97%. Sau ngay 20 phiit diu, c i hai Ioai loi ngd va vd ngd. Tuy nhien kdt qua tai bang vit lieu deu hip phu dugc mgt lugng Ion 3.2 cho thiy pH khdng inh huong nhidu den methylen xanh vcri hieu suit lan lugt l i 97,8% khi nang xu ly methylen xanh ciia ldi ngd v i va 97,6%. Trong khoang thdi gian tir 20-80 vd ngo.
phut, hidu suit hip phu khic bidt khdng that rd g-^g 3.2. Anh hu&ng cuapH t&i khd ndng hdp rang. Tuy nhien cd the thiy lugng hip phu phu methylen xanh cua loi ngo vd vo ngo methylen xanh dat hidu qua tdi da cua loi ngd
li 60phiit (99,2%); con vd ngd la 80 phiit (99,5%). Hip phu cua cac vit lieu thuong xay ra hai pha: hip phu bd m^t va hip phu mao din, methylen xanh chu ydu dugc h i p phu d dang pha diu nen ngay trong khoang thoi gian diu 20 phiit, khi nang hip phu d i tang manh.
Sau khi bd mit vit lieu d i no chit bj h i p phu, hieu suit ting rat cham va tham chi khdng tang ho^c giam din do qua trinh giii hip.
Kdt qua d bang 3.1 cOng cho thiy hieu suit g^^ ^ ^ c i hai VLHP, khi thay ddi pH tir hip phu ciia hai VLHP khdng cd su khic biet ^,1 ddn U.4 va vd ngd tu 3 ddn 8.7 hieu suit ldn nhung dung lugng hap phu cin bing (q) lai ^^^ pl^^ ^^ ^^ cao (tren 97%). Nhu viy buac cho thiy su khac biet lon. Vdi cimg khdi lugng ^^^ ^^ ^^ l^gt l u ^ ^ y i^ mdt thuin lgi cho VLHP 1 g trong 80 phiit hip phu thi Idi ngd cho ^^ ^ ^ ^ ^^ ly ^i VLHP vin hoat ddng tdt gia tri q I i 5,924 mg/g ldn hon gin 50% so vai ^ ^ g khoing pH rdng. Diy l i mdt uu didm v i vd ngd (3,963). Trong khoang thdi gian tLr_20 ^^^^ ^^^ ^4t 1^^ ^g ^p dung vao thuc td vi phiit ddn 80 phiit dung lugng hip phu can bang ^^-^^ ^.^^^^ ^ nhidm thucmg 6 nhidu mdi cua hai vit h?u khdng cd su bien ddi Ion. Tai ^ ^ ^ ^ p ^ ^^^ ^ ^ ^
« « ; tUrr^ ftiem nghien cuu, dung Iugng hip phu , . . .
mgi thm diem ngui , ^ v s> F K . 3 3 j ^ ^ ^^ ^ a ngng 35 methyl xanh r.fln hin<^ cua ldi ngd luon lan hon vo ngo. Nhu -^-f- ^ n n nuon^ cua """= - / ^ ^ X cT'tiid thiy loi ngd cd kha ning hip phu ^en k h i n i n g hap phu cua loi ngo va vo ngo.
methylen ' ' ^ ™ " ' * ' * ' ^ **' ^^^ ' ' ' ' " ' ^ ' ^ ^™S 3.3 cho thiy nSng do methylen .tanh TAP C H i KHOA H O C V.K C 6 N G NGHE L.AM N G H I f P S 6 2 - 2013 79
pH
3,1 5,0 7,0 8,8 11,4
Loi H 96,9 98,9 98,4 98,7 99,1
Dgo q(mg/g)
5,788 5,921 5,877 5,901 5,930
Vc H 97,9 98,9 98,8 99,2
ingS q(mg/g)
3,913 3,925 3,950 3,968
Quan ly Tai nguyen nmg & Moi tu&ng cang ting thi khi ning hip phu ciia loi ngd va vd ngd cd xu huong cang giim.
Bang 3 J . Anh hu&ng cda ndng dp methylen xanh den khd ndng hdp phu cua loi ngo
vd vo ngd Co (mg/I)
200 250 300 350
H,».„W 99,6 99,2 98,4 98,5
H . i . g i W 99,8 97,8 97,7 97,4
Ket qui d bing 3.3 cho thiy, khi ndng do metiiylen xanh tang len 2,5 lin thi hieu suit h i p phu ciia ISi ngd giim 3% (tir 99,6 xudng 96,6%), vd ngd ciing tuong tu khi ndng do ting tir 150-350 mg/l (2,3 lin) thi hieu suit giim gin 2% (tir 99,2 xudng con 97,4%).
Didu niy cd the dugc giii thich la do su chiem vi tri hip ph\i cua methylen xanh. Khi cac vi tri hap phu bj diy thi se dien ra qua trinh giii hip, do qui trinh iiip phu l i qui trinh can bing dgng nen lugng methylen xanh khdng dugc tiep tuc hip phu ma mgt phin methylen xanh bj giii hip, vi viy hieu qua giam din khi ndng dg ting.
3.4. Thao l u ^
Theo nghien ciiu ciia Dhuha D.Salman et al., (2012) khi xic djnh didu kien tdi uu dd hip phu methylen xanh ciia ming td bio tning ga thi hi?u suit xii ly dat gin 67%. Hay Vehnurugan. F et al., (2011) da chi ra khi ning hip phu methylen xanh ciia vd cam tuong ddi Idrn (gin 97%) tai pH = 10. Nhu viy ndu so sinh vdi ket qui nghien ciiu ciia tac gia thi kha ning hip phu ciia Idi ngd va vd ngd cho hieu suit rit cao co the Ien toi gin 99%, hon niia VLHP ldi ngd v i vd ngo dugc chd tao rit don gian v i chi phi thip.
So sanh voi mdt sd nghien ciiu trong nudc nhu theo tic gia Nguyin Tnic Lmh et al.,
(2010) thi Idp phii TiO? trdn ndn phosphate hap phu tot nhit methylen xanh phii mit khoang 2 gid nhimg hieu suit ciing chi khoing 77%. Tuy nhien ldi ngd va vd ngd trong nghien cuu cua tac gii thi voi thdi gian rit ngan (khoang 60 phiit) da dat dugc hieu suit tren 99%. Tuong tu nhu viy theo nghien cuu cua Nguyen Thj Ha, Hd Thi Hda (2008), ctmg 1 g VLHP tai ndng do methylen xanh xir ly ttr 50-lOOmg/I d dieu kien pH tdi uu thi bui bdng hoat hoa hip phu djtt hidu suit 98% trong 30 phiit. Trong khi loi ngd Xli Iy methylen xanh d ndng dg 300 mg/l (cao gip 3-6 lin) tai pH=7 trong BOphiit thi dat hieu suit d i len tdi 98,1%; hay vdi vd ngd d ndng do 200 mg/l ding dat tdi 99%. Nhu viy dung lugng hap phu methylen xanh ciia ldi ngd va vd ngd lon han so voi bui bdng hoat hda.
Loi ngd v i vd ngd l i hai dang phe phim ndng nghidp tuong doi phd bidn d Viet Nam;
phin bd nhidu nhit a Tiy Bic, Tay Nguyen va Ddng Nam Bg nen cd thd dd dang ap dung tip trung thu mua vdi sd lugng 1cm de xii ly moi truong d nhidm do methylen xanh trong nudc thii. Cic VLHP khac nhu mang td bio tning ga, vo cam, bui bdng hoat tinh khdng phd hien d Viet Nam, die biet Ii h i p phu bing lop phu Ti02 rit khd tim, kho chd tao v i chi phi cao nen tinh khi thi de xir ly methylen xanh khdng cao bang loi ngd va vd ngd. Nhu vay, budc diu cd thd khing dinh loi ngo va vo ngd h ^ phu methylen xanh uu viet hon hin so vai cac loai VLHP d i dugc nghien cuu trudc do.
IV. KtT LUAN
Vd ngd v i I5i ngd dugc xir ly mdt cich don gian thanh VLHP, hip phu dugc methylen xanh vdi hidu suit rit cao - Ien tdi tren 97%. Usp phu dugc mgt lugng ldn methylen xanh trong thdi gian ngin va trong khoang pH rdng la nhung uu diem ndi bat cua hai loai vit Ueu niy. Vdi loi ngo sau 60 phiit, v i vd ngd sau 80 phut tiiu dugc hieu suit cao nhit tuong iing Ii 99,2 va 99,5%. Methylen xanh dugc hip phu troi^
khoang pH rit rgng voi Idi ngd: tir 3 ddn 11, vd
80 T^JP CHI KHOA H Q C VA CONG N G H | : LAM N G H I f P S 6 2 - 2 0 1 3
Quan ly Tai nguyen rimg & Moi tn/dng ngd: tir 3 den 8,8. Khi ting ndng do methylen
xanh ddn 350 mg/l, khi ning hip phu cua ca loi ngd va vd ngd cd xu huong giam. Trong mgi dieu kidn thi nghiem ciia nghien ciiu nay, loi ngd ludn cd dung lugng hip phu cin bing lon hon gin 2 lan so voi vd ngo.
Loi ngd va vd ngd cd tmh kha thi cao trong Xli ly 6 nhiem nuoc thii do thudc nhugm methylen xanh. Die bidt day li hai dang phe pham nong nghiep rit ddi dao a Viet Nam, do do tiem ning iing dung ciia hai loai VLHP nay la rat Ion.
TAI LEEU THAM KHAO
1 Dhuha D. Saknan, Wisam S. Ulaiwi and N.M.
Tariq (2012), Determination the Optimal Conditions of Metf^lene Blue Adsorption by the Chicken Egg Shell
Membrane, Internationa! Journal of Poultry Science, volume II, page 391-396
2. Dang Xuan Viet (2007), Nghien ciru phuang pht^
thich hap di khd mdu thudc nhugm hogt tinh trong mrdc thdi del nhugm, luan an tien si kf thu^t, D ^ hoc Bach Khoa H4 Noi
3. Nguyin Thi Ha, H6 Thi Hoa (2008), Nghien cuu hdp phu mdu/xCr ly COD irong nudc thdi nhuQm bdng cacbon hoax hoa chi tgo tir bui bong, T?p chi Khoa hoc Dai bpc Qu6c gja Ha Ha N6i, Khoa hpc T\f nhien v i C6ngNghe.24: 18-22
4. Nguyin Thi Tnic Linh, Nguyin Hilu Tri, Nguyin v a n Dung (2010), Anh hudng ciia nhiit dp u den cdu True vd hoat tinh quang xiic tdc dia lap phu Ti02 trin nen phosphate. Science and Technology Development, 13:10-16
5. Velmurugan. P, Raihina kumar, V, Dhinakaran. G (2011), Dye removal from aqueous solution using low cost absorbent. Intematianal journal of environmental sciences, volume 1, page 1492-1503
METHYLENE BLUE ADSORPTION BY COB AND CORN HUSK Duong Thi Bich Ngoc, Nguyen Thi Mai Luong, Nguyen Thi Thanh SUMMARY
Research conducted experiments of adsorption capacity of methylene blue by Igram cob and Igram com husk in the different conditions of adsorbing time, pH and concentrations of methylene blue. After 20 minutes the adsorption process of methylene blue by cob and com husk had up approximately 98%. The process of adsorption reached over 96% in wide range pH from strong acids to strong alkalis: for cob from 3 lo 11; for com husk from 3 to 8.8. The adsorption process tended to decrease lightly, but still achieved about 97%, while concentrations of methylene blue increasing from200mg/l to 350mg/l. In the experiments cob always showed that its equilibrium adsorption was abnost 2 times higher compared with com husk. The research revealed that cob and com husk, two of the low cost absorbents in Vietnam, could be high potential for treating polluted wastewater by methylene blue.
Keywords: Absorbent, adsorption, agricultural waste, cob, com husk, methylene blue Ngu&iphdn bi^n: PGS. TS. B l Minh C h i u
Ngdy nhdn bdi- 30/5/2013 Ngay phdn bien: 02/6/2013 Ngdy quyit dinh ddng: 07/6/2013
TAP CHI KHOA HQC VA CONG N G H | : L.AM NGHEEP S d 2 - 2013
