Hgi nghi Khoa hgc ky niem 35 ndm Vien Khoa hgc vd Cong nghe Viet Nam - Hd Not 10/2010
XLT LY
NLTOC T H A ITlT CAC KHU KHAI THAC MO BANG
V A T L I E U K H O A N G VAPOLYME
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Phan Van Trirdng, Nguyen Xuan Tang, Le Thi Hoai Thu, Nguyen Due Niii, Le Thi Hai Ninh
Vien khoa hpc vat lieu truonRpv(a)ims.vast.ac.vn Tom tat:
Tren ca sd nghiin cieu khd ndng hdp phu ciia cdc vdt lieu khodng vd polyme diin hinh nhu bentonit hogt hda, zeolit vd cdc polyacryamid, cdc tdc gid dd di xudt phucmg phdp vd khd ndng icng dung chiing di xie ly chdt d nhiem trong nude thdi khai thdc - chi biin khodng sdn. Kit qud cho thdy, hiiu sudt xie ly dgt tic 90 - 96% ddi vdi cdc kim logi ndng vd tir 86 - 92%) ddi vdi cdc hpp chdt nita.
Abstract:
Based on research on adsorption capacity of mineral and polymer materials, as bentonit, zeolit and poly aery amids, authors propose treatment measures and their applications to pollutants in wastewater from exploiting and processing of mineral. Treatment efficiency reaches 90-96% for heavy metals and 86-92% for nitrogen compounds.
1. DAT VAN DE
Nude thai tir cac khu mo khai thac va che bien khoang san thuong co khoi lupng ldn, chira nhieu chat 6 nhiem va khong dugc xir ly trudc khi xa thang ra moi trudng tac dgng xau tdi moi trudng dat, nude mat va nude ngam.
Bang nhieu bien phap sinh hgc, boa hpc khac nhau, mot so noi da tien hanh ap dung, tuy nhien, hieu qua xir ly khong cao, mat khac chi phi thuong rat ton kem. Trong dieu kien khai thac, che bien khoang san d Viet Nam, viec sit dung cac khoang chat tu nhien va polyme trong xir ly cac loai nude thai loai nay hau nhu chua dugc nghien ciiu ling dung nhieu, vi vay, viec dua ra phuong phap xir ly phu hgp se gop phan tao dieu kien cho cac co sd khai thac mo ling dung trong xir ly nude thai, dam bao tieu chuan trudc khi thi ra moi trudng.
2. LITA CHON FHU'CNG PHAP VA VAT LIEU Xlf LY Nl/dC THAI 2.1 Vat lieu polyme
Theo nhirng ket qua nghien ciiu va ling dung cac vat lieu khoang va polyme trong viec xir ly nude thai cong nghiep, nude cap [1-5, 8, 10, 11], trong cong trinh thir nghiem nay, chiing toi lira chgn doi tugng nude thai tai cac diem khai thac titan ven bien va xir ly bang cac vat lieu polyme loai polyacryamid va khoang chat la bentonit boat h6a va zeolit tu nhien. Nhung dac tinh va kha nang ung dung chiing dugc mo ta nhu sau:
Cac polyme thuong co kha nang tan rihieu den hoan toan trong nude, do chung d trang thai v6
Tieu ban: Moi tnt&ng vd Ndng lugng ISBN: 978-604-913-013-7
dinh hinh, sip xIp khong dac kbit, lai co sir chuyin dgng cua cac mat xich, tao dilu kien cho cac phin tir dung moi (nude) dl Igt qua tao thanh dung dich. Polyme loai polyacryamid co dac tinh nli bat vl kha nang hip phu la khi boa tan trong nude va bi thuy phan trd thanh polyme mang tich dien am (moi trudng baza) hoac duong (moi trudng axit) (hmh 1).
Qua trinh kit tu va va kit tua cua polyme thong qua cac co cbl trung hoa dien tich vdi cac chit 6 nhiem trong moi trudng tinh dien. Cac chit dien phan co do tap trung dien tich cao se hiit bam ben tren nhiing khu vu'c phan tir mang dien tich trai dau. Cac dien tich trai dau tren cac phan tir kl nhau se kit hgp vdi nhau, dan din sir kit tu. Sir kit tu dugc phan loai chung theo ban chit cua dien tich ma chiing mang, chiing co thi la ion duong, ion am hay khong ion tiiy theo trpng lugng phan tir, mat do tich dien va do phan nhanh (hinh 2a). Nhiing phan tir kit tu nho, dugc hinh thanh do sir kit tua, tap hgp lai thanh mgt khIi kit tu ldn ban khi ket hgp vdi mot polyme (hinh 2b). Nhiing phan tir ldn ban dugc hinh thanh theo each nay day nhanh toe dp d6ng can. Theo each nay, sir bac cau giira cac polyme ma trong do chat dien phan bao hoc phan tir kit tu hinh cbuli dugc moc vao nhau va du dua cd the gan lien vdi nhiing phan tir gin ben (hinh 2c) [8, 9].
-CH2-CH-
N H 9 - n
nH" =
-CH2-CH-
N H ^ n
-CH2-CH-
r
+ nOH"NHT^n
COO-
-CH2-CH-CH- + nH20 NHr^n
a) b Hinh I: Qud trinh thuy phdn polyme tich diin duang (a) vd tich diin dm (b) [I, 2, 6]
Polyme mang dien tich
duong
Cac phan tir mang dien tich
am
Phan tir baton
dinh
Phan tir bat on dirih
Su phat trien cua phan tir ket
tu Ket tu tao cau noi Hinh 2: Co chi trung hda - kit tiia diin tich vd kit tu qua viec tgo cdu ndi polyme [6]
2.2 Cac khoang chat
Dli vdi cac khoang chat, kha nang xir ly chit 6 nhiem do dac trung bdi cac tinh chit sau:
- Tinh truang nd: Do c6 ciu triic dang tinh thi phan lap lien kit, khi bao hoa nude, qua trinh bydrat hoa lam thi tich tang len 15 - 20 lin. Ban dau chiing hip thu phin tir nude tren cac tam hip thu giua cac Idp, cac cation tin tai trong do vi su thay thi vao cac niit mang tinh thi nhu Al^"", Fe^"',...thay Mg^"", Fe^"',...gay thira dien tich am. Moi cation bj bydrat boa bdi 3 - 6 phan tir nude va lam tang khoang each giira cac Idp din 5A.
- Khd ndng trao ddi ion: Chiing dugc thi hien qua su thay dli ding hinh cua cac cation
Hgi nghi Khoa hgc ky niem 35 ndm Vien Khoa hgc vd Cong nghe Viet Nam - Hd Noi 10/2010
trong mang cau tnic tinh the lam xuat hien dien tich am. Dung lugng trao doi ion phu thuoc vao sd lugng dien tich am be mat, do pH cua moi trudng va co the dugc can bang bdi cac nhom hydroxyl thay the nguyen tir oxi trong cau tnic.
- Tinh hdp phu: Do dac tinh be mat xop (be mat ngoai va trong) nen cac khoang chat co kha nang hap phu, chung co the hap phu cac hgp chat dudi dang cation hoac cac cac cation trao doi. Miic do hap phu tiiy thuoc vao kich thudc cac mao quan va kich thudc hat, hat cang nho, dien tich be mat ngoai cac ldn, trong khoang 500 - 700m7gam [2,3,6,7].
2.3 Phirong phap xii" ly nirdc thai mo tai phong thi nghiem
Bang cac budc hda tan polyme thanh dung dich, sau d6 tien hanh khuay trgn trong thdi gian nhat dinh, chiing toi da lira chgn dugc quy trinh ky thuat xir ly nude thai trong khu mo khai thac titan Ky Khang (tinh Ha TTnh) dat hieu qua cao nhit (hinh 3).
4. KET QUA THI NGHIEM
Sau khi thi nghiem vdi cac loai vat lieu tren nude thai khai thac mo, ket qua xir ly dat hieu suat cao nhat doi vdi polyme d miic l,Og, bentonit boat hoa d miic 4g va zeolit tu nhien la 15g tren Im^ nude thai (bang 3, hinh 4).
Neu sir dung bentonit hogt hoa: 3,4,5,6g/m^ nude thdi Neu sir dung zeolit: 10-15- 20g/m^ nuac thdi
Mau nude thai
Lang, loc (15 phut) tdch cdn
Neu sir dung polyme: Pha dung dich polyme (Ig/lit mcdc cdt, pH >« 7), xie -ly v&i 0,5-1,0-1,5 lit dung dich/m^
nuac thdi -khudy 150 vong/phiit,
thdi gian khudy Id 45 phitt
Phan tich mau
Ket qua
LTinh 3: So dd nguyin ly xir ly nude thdi md bdng cdc polyme vd vdt lieu khodng Bdng 3: Kit qud xir ly nude thdi [6]
Chi tieu
As TSS
Ham lupng ban dau
0,04 132,4
Ket qua xir ly (mg/l)/hieu suat (%) Polyme
(0,5g) 0,008 11
Bentonit boat hoa (4g)
0,018 10
Zeolit (15g) 0,03
25
QCVN 08:2008
0,01 20
QCVN 09:2008
0,05
-
Tieu ban: Moi tru&ng vd Ndng lugng ISBN: 978-604-913-013-7
NH4^
Pb Fe Cr Zn N03- Mn
Dau md khoang
0,97 0,04 6,14 0,015
0,07 0,45 1,27 0,35
0,09 0,001
0,18 0,006 0,028 0,087 0,04 0,001
0,11 0,03 2,11 0,007 0,043 0,11 0,45 0,008
0,7 0,03
3,1 0,012
0,05 0,27 0,78 0,18
0,1 0,02
0,5 0,01
0,5 2
- 0,01
0,1 0,05
5 0,05
3,0 15 0,5 -
Ghi chit: QCVN 08:2008/BTNMT - Quy chudn ky thuat Qudc gia vi chdt luong nude mat;
QCVN 09:2008/BTNMT - Quy chudn ky thuat Qudc gia vi chdt luang nude ngdm.
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Hinh 4: Hieu suat xir ly nude thai khai thac mo bang vat lieu polyme (a) va bentonit (b) [6]
5. DANH GIA VA THAO LUAN
Ddi vdi kim logi ndng (As, Fe, Zn, Mn): Kha nang hip phu cua polyme la tuong dli cao.
Dli polyme cho hieu qua cao nhat, hieu suat dat tir 90 - 96%) d miic 1 ,Og/m'^ nude thai.
Cac khoang chat (bentonit hoat hoa, zeolit) co kha nang xu ly kim loai thip ban. Dli vdi bentonit boat hoa, hieu suat xir ly doi vdi Fe la cao nhit d khIi lugng nguyen lieu la 4g/m^
nude thai - hieu suat dat 61.1%. Trong khi zeolit tu nhien, vdi miic nguyen lieu 15g/m^
nude thai, hieu suat xir ly Fe chi dat 49,5%.
Ddi vdi cdc hpp chdt nito (NHf, NO/): kha nang xir ly nude thai cua polyme d miic l,Og, hieu suat cao nhit dat NH4'': 92,0%, NO3': 80,7%. Tuong tu thi nghiem tren bentonit boat hoa, d miic 4g/m\ kit qua dat dugc la cao nhit, trong do NH4"': 91.7%) va NO3": 86.0%.
Rieng dli vdi zeolit tu nhien c6 hieu suit xir ly thip nhit, kit qua cho thiy ring, dli vdi
Hgi nghi Khoa hgc ky niem 35 ndm Vien Khoa hgc vd Cong nghe Viet Nam - Hd Not 10/2010
kim loai nang thi Fe dat cao nhit la 49,5%, cac hgp chit nito dat tir 27,1 - 40%.
Chdt rdn la lirng (TSS): hieu suat xir ly tuyen tinh vdi khoi lugng nguyen lieu. Xir ly vdi polyme d miic 0,5 - l,5g/m^ nude thai, hieu suat dat tir 91.7% - 98.1%.
Ddi vdi ddu ma khodng: Cac polyme gan nhu xir ly triet de dau md khi khoi lugng nguyen lieu la 1,0 g/lm nude thai, khoang chat bentonit boat boa ciing cho ket qua tot d miic 4 gam/1 m'' nude thai. Rieng vdi zeolit, kha nang xir ly kem ban, chi hap phu toi da 50% ham lugng 6 nhilm d mirc 15 gam/lm^ nude thai.
Tren co sd so sanh vdi gidi ban cho phep la cac Quy chuan ky thuat Quoc gia ve chat lugng nude ngam va nude mat, cac chi tieu 6 nhiem sau xir ly bang cac polyme va nguyen lieu khoang d miic do nao do dat tieu chuan thai, dam bao trong viec xa thai ra nguon tiep nhan.
6. KET LUAN
Nude thai trong cac khu khai thac, che bien khoang san thuong c6 khoi lupng ldn va chiia nhieu chat 6 nhiem nhu As, NH4'^, Pb, Fe, Cr, Zn, NO3", Mn,... la nguy co gay 6 nhiem moi trudng dat, nude ngam va nude mat.
Tren co sd nghien ciiu trong phong thi nghiem kha nang hap phu cua cac vat lieu khoang va polyme dien hinh nhu bentonit boat boa, zeolit va cac polyacryarnid, bang phuang phap vdi cac budc don gian gom hda tan (doi vdi polyme) va khuay tron vat lieu vdi nude thai. Ket qua cho thay, hieu suat xir ly dat tir 90 - 96% doi vdi cac kim loai nang va tir 86 - 92% doi vdi cac hop chat nito, ngoai ra, doi vdi mgt so chi tieu nhu dau md, chat ran lo limg hieu suat xir ly dat tren 85%. So vdi tieu chuan cho phep, nude thai sau xir ly dam bao chat lugng thai ra moi trudng.
TAI LIEU THAM KHAO
1. Ta Quoc Hiing, 200S, "Nghiin ciru che tgo bentonit hogt hda sir dung nguyen lieu bentonit Cd Dinh - Thanh Hda vd icng dung trong cdng nghi xir ly nude thdi chi biin thuc phdm",.
2. Duong Van Nam, 2007, "Nghiin ciru cdng nghi xir ly nude thdi ciia cdc ca sd chi biin thuc phdm bdng vdt lieu bentonite hogt hda ", Bao cao ket qua de tai cap Vien Khoa hgc Vat lieu.
3. Pham Minh Tii, Dang Kim Chi, Hoang Thu Huong, Tham do kha nang xir ly nude thai cua cac che pham zeolit X, A dugc tong hgp tir cao lanh khong nung. Tuyen tap bao cao Hgi thao Quoc gia Dia sinh thai va cong nghe moi trudng. Hgi Dia boa Viet Nam (2006).
4. Le Diic Trung, 2007, "Sir dung vdt lieu hdp phu tu nhiin di xic ly kim logi ndng trong biin thdi cdng nghiep ", Tap chi phat trien KH&CN, tap 10, so 01/2007.
5. Dang Kim Chi, 2006, "Khd ndng logi trie As bdng than gdo dira Viet Nam d hd gia dinh ", Tuyen tap bao cao khoa hgc Hgi thao Quoc gia Dia sinh thai va CNMT - Hgi Dia hoa VN.
6. Phan Van Trudng, 2007, "Nghiin ciru xir ly nude thdi tgi cdc diem khai thdc, chi biin sa khodng Titan ven biin miin Trung bdng vdt lieu khodng vd polyme", Bao cao ket
Tiiu ban: Moi tru&ng vd Ndng lugng ISBN: 978-604-913-013-7
qua de tai cap Vien Khoa hgc Vat lieu.
7. Qian Guang-ren, YuLi-jia, Xia Fang-yuan, 2006, "Surfactant scouring wastewater modified bentonites - promising material for unmanageable wastewater treatment", Journal of Shanghai University, Volume 10. Number 1.
8. Howard H. Lo; Yung-Tse Hung, 2005, "Utilization of clays and zeolites for coagulation treatment of municipal wastewater. International Journal of Environmental Studies ", Volume 37, Issue 3^
9. Hossein Eisazadeh, 2008, "Removal of Arsenic in Water Using Polypyrrole and its Composites", World Applied Sciences Journal 3.
10. Jan Veres, Zuzana Orolinova, 2009, "Study of the treated and magnetically modified bentonite as possible sorbents of heavy metals". Acta Montanistica Slovaca, Rocnik 14 cislo 2.
11. Vengris, T., Binkiene, R., Nickel, 2001, "Copper and zinc removal from waste water by a modified clay sorbent", Appl. Clay Sci. 18.
