Nghien cCu - Trao doi
Nghien cuU che tao than ho?ninh lam tir loi ngo bang phirtfng phap dot yem khi
Ohg dung xilr ly chat huti ctf trong niitfc
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O VU THI HAI, LE TH! TRINH, TRINH TH! THOY Trttdng Dai hoc Tii nguyin vi Mdi tnldng Hi Ndi
H
ign nay, mdt htfdng dl mdi nham htfdng tii itfi ich KT-XH va mang lai y nghia quan trgng trong llnh vtfc BVMT la tin dgng, tii si dgng va tii chd chat thai. Didu niy da dutfc Chinh phi dua vio MtfC tieu Chign itftfc BVMT qudc gia cia Vigt Nam nam 2010 vi dmh hudng den nam 2020, dd ia tip trung hinh thinh vi phit trien nginh cdng nghiip tii chd chat thai Cic htftfng nghien^ciu xily ntfdc d nhiim bang cic vgt iigu dtftfc chd tao ttf cac chdt thii, vit ligu cd sin trong ttf nhien nhtfvo trau, vo Igc, xtfdtfa, xtfday, ba mia, gio dtfa dang dutfc cic tic gii quan tam nghien ctfuva thtfc hign trin toin thd gidi ndi chung va Vigt Nam ndi rieng. Uu didm cia cic vit lieu niy li sin pham tgo thinh cd gii thinh thdp, thin thiin vdi mdi trudng vi cd the ing dtfng d cic quy md khic nhau. 6 nhiem chat hOu ctf trong ntfdc thai sinh hoat vi cdng nghigp dutfc xi ly bang phtfang phip sinh hge, tuy nhlin vin khdng dat tieu chuan cho phep trudc khi thai ra ngoii mdi trtfdng do dd cin xiiy tang ctftfng bang phtfang phip hap phg.
Muc tiSu nghiSn cdu Thtfc nghiim
Mau nghlSn cdu bao gdm mau nddc tU pha trong phdng thf nghiem cd ndng dp 50-200mg/l.
Che tgo vit iiiu. VSt lieu hip phu dupc che tao td Idi ngd p h i thai theo quy trtnh sau: Ldi ngd p h i thai ddpc rda sach, de khd td nhien, sau dd say 8 100°C trong 2 h, d l ngudi, xay nhd, rfty, sang phan vat iieu thd cd kich cd td 0.5 - 2 cm. Hoat hda vat lieu thd bang dung djch KOH (25g KOH pha trong 1 iit nddc cat) vdi ty IS trdn idi ngd; Dung djch KOH xftc djnh trong 4h; rda vat lieu sau khi ngftm d i n khi dung dich rda dat pH 7 - B; iam khd vat lieu trong td say 8 nhiet dd 110°C trong vdng 24h. Nung vftt lieu da hoat hda 8 cftc mdc nhiet dd trong khoang 500 -
900°C trong 2h, lay vftt liSu sau khi nung ra, d l ngudi trong binh chart khdng. Tilp tuc rda than sau nung bang dung djch HCl 3N de pH cda than dat7- 8, sau dd sly than trong 12h.
Cac didu kign khao sit trong thi nghigm: Anh huSng cua nhlSt dd nung than ddpc tiln hftnh tai cac nhiSt: 500,600,700,800,900''C, ti le trdn loi ngd: Thl tich KOH Ift 1:10. NghiSn cdu ftnh hdSng cda ti IS trdn loi ngd (gam): T h l tich KOH (ml) ddpc tiln hdnh tai cftc tl le 1 ;3, T.5,1 ;7,1 ;10 tai nhlSt dp nung tdi du.
Dinh gii hiiu qua xi ly chat htfu ca trong nude cua vit lieu: Nghien cdu da tien hanh danh gia hieu qua xd ly chit hdu cd trong nddc cda vat IISu c h i tao 8 cftc dilu kiSn khac nhau trln nen mftu gia djnh cd h4m Idpng COD 50-200mg/l 8 cac dieu kien pH kh4c nhau vd mau cd ham Idpng COD khdo nhau.
Xac dinh dac trung cdu true cua than: Mdt s6 thdng sd dac trdng d l xdc dinh c i u trdc cda than da che tao bao gdm: Dien tich be mat riSng ddpc xftc djnh thep phdPng phap BET, dd am xac dinh theo phdPng phap phftn tlch khdi lupng, chup ciu trdc bang phupng phdp kinh hien vi dien td qudt SEM.
Ket qud nghien cufu
Anh hudng cua nhiet do nung ddn khi nang 1^
phu cua than: K i t qua khao s4t cho thay rang hidu suit hip phg cua than phg thudc vao nhiet dp nung, hieu suit hip phu COD cua than tang td 6 - 63%
tuong dng vdi cac mdc nhiet dd nung tang td 500- 800°C vft sau dd giftm xudng 58% khi nung 8 mdc nhiet dp 900°C. Dieu nay cd the ddpc giai thich khi quft trinh than hda xay ra 8 nhiet dd eftng cao trong mdc gidi han thl than thu dupc cd cau true eftng xdp hay b l mat riSng cua than eftng phftt trtln. Do dd, nhiet dp tdi du cda q u i trinh tap than tai 800°C trong 2h.
2 8 Tdi nguyen yg Mdi tru'dng | Ky 2-Thing8/2616
B^ng 1: Kit qua khao sat inh hudng cua nhi$t do din khi nang hip phu cua than
Stt 1 2 3 4 5
Loai than CoC) 500 600 700 800 900
Co (mgA)
COD=
52 mg/1
(mg/1) 49 47 39 19 22
Hieu suat xiV
6 10 25 63 38
Kdt qui xic dinh dgc trtfng tinh chat cia than K i t quft phan tich dien tfch be mat ridng bang phdn tich hap phu N2 cho thdy dien tich b l mat than boat tinh ddpc heat hda bang KOH cd S B E T = 891,7620 m^/g, tdPng dpi cao. Ket quft chgp ftnh be mat cua than d cdc mdc dd phdng dai khfte nhau bang may dien td quyet SEM tai hinh 1 cho thiy;
Hinh 1 : Hinh inh SEM cua loi ngb vi than hoat tinh
Biing 2: Ket qui khao sat inh hudng cua tl Ig trdn ddn kha nang hdp phu cua than
Stt I 2 3 4
Tl le b'on 1:3 1:5 1:7 1:10
Co (mg/1)
COD
= 244 mg/1
Sd, (mg/1)
102 107 122 134
Hicu suat xir
iy(%) 58 52 50 45 Ghi chu: Co: Ndng do COD ban dau, C^: Nong db COD tai cin bang
Anh hudng cua ti ie trin gitta idi ngb va dung dich KOH den kha nang hap phu cia than: K i t quft q u i trtnh khao s4t hiSu sua't xd iy COD cua cac ioai than ddpc tao thSnh td cac mdc ti IS trdn kh4c nhau gida vat liSu idi ngd vd tdc nhftn hoat hda KOH dUOc thdng ke tai bang 2. Lupng hda chft't cho vdP cd tftc dgng 14m tac nhftn khd hda hpc Ift khd hydrat tap dilg kien cho cac hpp cha't hOu cP trpng vftt lieu dS dftng bj phan hdy dddi tftc dung nhiSt va quft trtnh oxy hda, mdt sd nguySn td eacbon bj dd't chfty thftnh CO, CO2, khi ndy bay ra d l lai chd trdng, tao dd rong xdp cho than.
Td dd thj cd the nhftn thiy hieu sua't xd iy COD 8 tl le trdn tdt nhft't 14 1:3 (Igam vat lieu thd: 3mi dung djch KOH). Khi the tich axit t4ng hPn tai tl id 1 ;5,1:7, 1 ;10 ) thl hilu suit hip phu COD cua than tap thanh giam dan td 58- 45% vi Idpng axit dd khdng cd tac dung tao dp rdng xdp vft phftn buy chft't hdu CO cda than boat tinh thftnh pham.
Than hoat tinh d dd phdng dai 900 ian K i t quft cho tha'y than heat tinh dupc heat hda bang KOH khi nung 8 800°C cd cau true cftc Id rdng sau rd ret x l p gan nhau nhu mdt he thdng id tang ong. Chinh cftc Id rdng nfty Idm cho kha nang hap phu b l mat cda than c h i tao ddpc tdt hdn rit nhilu lan so vdi b l mat cda vat iiSu idi ngd thd ban dau.
Toi nguyen yg Mgi tru'dng | Ky 2-Thing 6/2016 2 9
Nghiin ctfu cic ydu td anh htfdng cua qua trinh hap phg COD cia than hogt tinh
Nghien cttu anh hudng cia pH: K i t qua khdo sat hieu suit xd ly COD cua than qua c4c gid tri pH khfte nhau dUdc bilu diln tpi hinh 3 cho thiy khi pH trong dung djch COD d i u vac tftng khoing td 4-10 thl hieu suit hip phg COD cda than giam din td 67 - 28%. NghTa 14 khi pH cua dung djch ban diu cang tang thl kha nang hap phu COD trong dung djch do cda than cdng giftm. Hieu suit hip phu cao nhat 8 mdc pH = 4. Do dd, mdc pH tdi du cho qua trtnh hap phg COD cda than mft d l tai Ida chpn Ift pH =4.
Hinh 2:H/eu suat xi ii COD cua than theo pH
Hieu suat h i p phu ciia than theo ham luffng CODdSuvao.
il
m 1
inh I
Hinh 3: Higu suit hap phg cia than theo ham iuang COD dau vio
Nghiin cttu inh hudng cua ndng dd COD dau vao den hiiu qua xi iy: Ket qua khao s4t hidu suit xd ly COD cua than tao th4nh qua c4c mdc ham Idpng COD diu V4P khfte nhau cho thiy, khi hftm iupng COD dau vfto tang din td 57 - 257 mg/1 thl hieu suit hap phu COD cda than tddng dng giftm din td 67- 44% NghTa Ift khi hftm idpng COD ban dau c4ng nhd thl kha nang hip phu cda than cang tdt. Hidu qua hap phu id tddng ddi cac, tddng td nhd kit qua hap phu COD cua than heat tinh td mdt sd nghien cdu khfte nhu tftc gia Nguyin Thj Ha va cdng sd da nghien cdu xd ly boat
hda bui bdng bang cdch ddt vdi axit sunfunc d^m i ^ , cho hidu suit hap phg mftg/COD kho&ng 70%, vdi"
IS COD/vat iiSg hap phg Ift 40mg/g. Than heat tinh ddpc tao ra td vd san cho hiSu qgft hip phy COD a 86%, dien tich be mftt rtSng SgEx la 430,05 nflg.
KS't luan va kien nghj
Tban hoat tinh che tao td Idi ngd ddpc heat hoa bang KOH cd k h i nang hap phg cac chit hOu cd trong nddc. K i t quft nghiSn cdu bddc d i u trong phdng thf nghiSm cho thiy than ddpc tao thftnh d mdc tl IS trpn 1:3 (1 g idi ngd:3 ml KOH) vft nung 6 nhiet dd 800°C cho hieu suit xd ly COD Ift cao nhat Than thftnh phim cd dac diem tinh chit gidng than hoat tinh thuong pham nhd SgET = ^^^ '^5^ m'lg, anh chup SEM cho thay than cd elu trdc gidng ting ong cd nhilu Id x l p canh nhau lam tang dien tich tilp xdc cua than tren be mat, kich thddc mao quan cda than trong khoftng 20- 30Mm, phu hop de lam v4t IISu hap phu trong xd ly mdi trddng.
Trong khoang ndng dp COD td 50 den 250mg/l, hieu suat xd ly COD dat 67% tai pH tdi du tpi 4 va thdi gian 30 phut vdi he tinh. Cac nghien cdu tilp theo se khao s4t cP che cua qu4 trtnh hip phg, khao s4t tren he thi nghiem ddng d l cd cd s8 ftp dung trong thuc tidn.
Tai lidu tham khdo
1. Le Van Cat (2002), Hdp phu vi trao ddi ion trong ky thuat xi li ntfdc thai. Nxb Thdng ke, Hd Ndi.
2. NguySn Thj H4, Hd Thi Hda (2008), •Nghiin cttu hdp phu mau/xO iy COD trong nUdc thii nhuim bang eacbon hoat hda che tao ttf bgi bdng, Khoa Mdi trudng, TrUdng Oai bpc Khca hpc TU nhiSn.
3. Ddng Thj HuS (2012), "Nghien cttu ehe tgo than hoat tinh ttt vd trau bang phttdng phip oxy hoa vi ttng dung lam chat hap phu trong xi iy ntfdc Ml", Trudng Dai hpc Dan lap Hai Phdng.
4 TranVan Hdng (2011), "Nghiin ctfu chd tao than hogt tinh ttt vo sin vi ing dung iim vgt lieu hap phu mit sd chdt htfu ca". Dpi hoc Da Nftng.
5. Nguyin Tran Thien Ly, Trln Thj Thu Ha (2013), "Nghien cttu kha nang xi iy miu nttdc thii det nhubm cua vat liiu hdp phu chd tao ttfba mia", Khoa Cdng nghe mdi trudng, TrUdng Dpi hpc Lac Hdng.
6. D.lpanidou, A zabaniotou (2006), "Agricultural residues as precursors for activated cartion production - Areview". Chemical Engineertng Department, Aris- totle University of the ssaloniki, Greece.
7. W.T.Sai (2005), "Preparation and characteri- zation of activated carbons from corn cob". Deapart- ment of Environmental Engineering and Health, Chia Na College of Pharmacy and Science, Taiv»an.«
3 0 Toi nguyen yg MSi tru'dng | Ky 2 - Thing 6/2016