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TAP CHI HOA HQC T 5I(1)121 126 THANG 2 NAM 2013 NGHIEN CU''''U DI^U CH^ THAN HOAT T INH TIT PHg THAI N O N G NGHIEP {ROM RA, TRAU) Le Ha Giang, Ha Quang Anh, Nguyen Trung Kien, Dao Dire Canh, Hoang Thi T[.]
TAP CHI H O A H Q C T.5I(1)121-126 THANG N A M 2013 NGHIEN CU'U DI^U CH^ THAN HOAT T I N H TIT PHg T H A I N O N G N G H I E P { R O M - R A , T R A U ) Le Ha Giang, Ha Quang Anh, Nguyen Trung Kien, Dao Dire Canh, Hoang Thi Thu Thuy, Tran Thi Kim Hoa, Dang Tuyet Phiro-ng va Vu Anh Tuan' Vi?n Hda hgc Vi?n Hdn Idm Khoa hgc va Cdng ngh? Vi?t Nam Den Tda sogn 25-9-2012 Activated carbon was successfully produced from char-side products of the pyrolysis of rice straw lo produce biooil The obtained activated carbon was characterized by FE-SEM, BET EDX From the chacracterization results, it revealed that the active carbon showed high surface area (1600-2506 mVg) with uniform pore size distribution of (1.92.2 nm and 2-3 nm) The obtained product exhibited very high adsorption capacity of 70-93% for both polar solvent (acetone) and unpolar one (m-xylene), opening, the high application potential as new and effective adsorbent for environmental treatment I MO DAU Viet Nam la nudc xual khIu ggo dirng thir hai tren the gidi Trong qua trinh san xuat lua gao hang nam da tgo khoang 40 trieu tan ram la san pham phu - phe thai chiem gan 66% san pham phi thai nong nghiep Viec chuyen hda ram rg bang phuang phap nhiet phan tao nhien lieu sinh hgc (dau sinh hgc) ddng vai trd quan trgng an ninh nang lugng qude gia Ngoai ra, san pham phu ciia qua trinh nhiet phan rom la chat thai ran cd the diing lam nguyen lieu dau de che tgo than hogt tinh Tren the gidi, viec che tao than hoat ti'nh tir phe thai ndnjf' lam nghiep dvim quan lam nghien ciru va phat trien [1, 13] Than boat tinh che tgo tir phe thai tren dugc ling dyng rgng rai viec xir ly nudc sinh hoat va nirdc thai, xir ly kim loai nang va asen nudc, xir ly khdng bi d nhiem bdi cac chat hiru ca dgc hai va dac biet dugc diing de loai bd cac chat cue dpc - nguy hgi nhu dioxin, furan [15, 17] Viet Nam, viec nghien cuu che tao than boat linh tir phe thai nong-lam nghiep nhu trau, miin cua da duac trien khai nghien ciru, luy nhien viec che tao than hoat tinh tir phe thai ndng nghi?p ram it dugc quan tam Trong bai bao nay, chiing tdi trinh bay ket qua nghien ciru ehl tgo than boat tinh lir phi thai nong nghiep ddng thdi nghien ciru dac trung cau triic than hogt tinh long hgp dugc va kha nang hap phu ciia logi vat lieu mdi THUC NGHIEM 2.L Qua trinh nhiet phan rem, rg Dieu kien ciia qud trinh nhiet phdn ram rg- nhiel dp nhiet phan: 550°C, tdc gia nhiet: I5''C/phiit, Idc ddng mang N2: 10 ml/s, thdi gian: 20 phut Nhu vay vdi dieu kien nhiet phan klidng cd xiic tac nhu tren chiing ldi da thu dugc kit qua: san pham pha khi; 20-30% San pham pha long: 45-48% San pham ran: 25-30% 1.1 Qua trinh hoat hda than Chung tdi da lien hanh nhieu thi nghiem vdi nhieu each thiic khac nhu thay ddi ty le than/KOH hoac NaOH, thay ddi kbdi lugng san pham dua vao boat hoa, va sau dd dem danh gia sa bg cac san pham thu dugc bang kha nang hap phu iTnh va da riil dugc mdt quy trinh tao vgl lieu bap ph^i tdt nhat nhu sau: Phe thai lir nbi?t phan ram dugc tam vdi dung dich NaOH hogc KOH vdi ndng dp M sly 12 gid d nhi?l 100°C dl duoi hit nudc Hoat hoa than d nhiet dg 700-800''C gid, toe dg N2: 5-7 ml/s, tdc dg gia nhiet lO^C/phiit San pham thu dugc ciia qua trinh hoat boa trung hoa bang HCI 0,1 N, rua sgch san pham tdi pH = bang nudc cat, sau dd dem say d 100°C den kho —> thu dugc vat lieu than boat tinh (bao va Anh Tuan vd cgng Sir TCHH, T.51(l), 2013 quan binh kin) Sa cua qua trinh hogt hda than dugc thi hi?n hinh Nguyen li?u sau dugc tim KOH ho^c NaOH da say khd se dugc cho vao ong phan ung (4) va dugc Idt mgt Idp bdng gom (5) mdng d hai dau Ld phan ii-ng (3) dugc dieu khien bing thiet bj gia nhi^t (7) va on djnh nhi?t bing can nhi$t (2) Ddng tir binh N2 (I) se duoi het khdng Irong ong phan ling va cuon theo cac sinh qua trinh hogt hoa di ngoai va di vao tu hiit (8) Hmh 1: Qua trinh hogt hoa than I Binh N2, Can nhi^t, LP phdn irng, 6ng phan irng, BSng gom, Nguyen lieu, Thiel bl dieu chinh nhiet do, Tii hiil Than hogt tinh dugc dgc trung bang phuang phap: EDX tren may JED-2300, FE-SEM (do tren may HITACHI S-4800) vdi dg phan giai tir 300 nm din iim, BET (Thilt bi TriStar 3000) KET QUA VA THAO LUAN 3.L Thanh phan hda hgc, cau triic than boat tinh Thanh phan hda hgc ciia than boat tinh dugc che tao tir ram va Irau dugc phan lich nhd phuong phap EDX, cac kel qua dugc trinh bay d bang boat tinh chii yeu chira cacbon (82-87% nguyen tu) Ngoai cdn cd mat cac nguyen to oxi, Silic va ham lugng nhd cac nguyen Id kim logi nhu: nhdm, sIl, kali, canxi va titan S\r cd mgt ciia oxi phan ciia than boat tinh nam dudi dang cac nhdm chirc cacbonyl be mat Ham lugng silic la su phan bi?t ldn nhat giira than boat tinh che tao tir ram (0,58%) va than boat tinh che tgo tir triu (3,05%) De hieu rd ban s^' thay ddi phan hda hgc anh hudng the nao den cau triic vgt lieu chiing toi tien hanh SEM va BET 3.2 Hinh thai cua than Bdng 1: Thanh phan hda hgc ciia than boat tinh che tgo tir ram-ra va trau Nguyen to {% nguyen tu) C Si Mg Al K Ca Fc Ti Than hoat tinh (rom-ra) 87,17 0,58 11,2 0,08 0,37 0,36 0,07 0,11 0,06 Than ho^t tinh (trau) 82,42 3,05 12,92 1,05 0,28 0,21 0,04 Tir bang I cho thay, phan hda hgc cua than 1.1 Phucmg phdp chgp dnh SEM De xac djnh hinh thai cua than hogt tinh dieu che dugc, chiing tdi lien hanh chyp SEM ciia vat lieu Hinh trinh bay anh SEM vdi dg phan giai khac ciia than hogt tinh tir rom-rg va than hogt tinh tir trau Quan sal tir anh SEM ta thly than hogt linh dugc dieu che cd dgng tam (rgng 2-3 pm va day 0,8-1 ^m) dugc hinh tir hgt cd ddng deu cao 20-30 nm sap xep theo thiir ty hinh nen h? mao quan trung binh thu d p (10-15 nm) vdi than hoat tinh tir ram rg va (20-30 nm) vdi than hogt tinh tir trau Chinh cac h? mao quan thir cap cho phep than hogt tinh cd kha nang hap phy d ap suat rieng phan cao (P/Po> 0,5-1) ngung ty mao quan 122 rCHH,T 51(1), 2013 Nghien cuu dieu che than hogt tinh 3.2.2 Hdp phu vd khirhdpphy nita (BET) D I xac dinh dien tich be mat cung nhu dg xdp (kich thudc Id xop, thi tich Id, va sy phan bd Id xdp) cua than boat tinh, chung tdi lien hanh nghien ciru hap phu N2 theo phuang phap BET Tinh chat xdp cua vgt lieu dugc nghien cuu bing each hip phy va giai hap ding nhi^t N2 d 77 K, Dudng ding nhiet hap phy - khij hap phy N2 ciia than hogt tinh (hinh 3A va 3B), phan bo kich thudc Id theo BJH (hinh 4A va 48) Theo phan loai ciia lUPAC, dudng dang nhi?t hap phy N2 cd dgng I va dac trung cho he vat li?u cd cau triic vi mao quan dugc the hien d hinh 3, va bang (A) (B) Hinh 2: Anh SEM ciia vat lieu than hogt linh tir ram rg (A) va than boat tinh di lir trau (B) Tir dudng hap phu-kbu hip phu N; ta thay cd su khac biet d ap suit rieng phin thlp P/Po = 0-0,3 xay su hip phy nhanh qua trinh hap phu don Idp N2, d ap suit rieng phin cao tir 0,4-0,8 ta thay kha nang hap phy N? gan nhu bao hoa, dieu co the hiiu la vgl lieu tdn tai rat it mao quan trung binh (0,124-0,134 cmVg), dd tang ap suit len qua trinh hap phu vao mao quan rat it vay lam cho lugng N; hap phy vao vat lieu CO chieu hudng bao hoa Dien tich be mat theo -HXC-h G™ is? phuong phap BET dugc tinh dogn tuyen tinh ciia sy hip phy (P/Po < 0,2), cac gia tri ciia cac dac Irung cau triic nhu: dien tich be mat rieng thu dugc la SBET = 2506 mVg ddi vdi than hoat ti'nh di tir rom va SBET = '660 mVg ddi vdi than boat tinh di lir trlu Sy phan bd kich thudc mao quan (hinh 4A, hinh 4B) cho thly vi mao quan cd kich thudc ddng dlu, dudng kinh mao quan trung binh nam khoang 1,9-2,2 nm vdi than hogt tinh tir ram-ra va 2,0-3,0 nm ddi vdi rom tir trau I.oUltmiLjn.uPlol / T/ i™ ; Rel ',,?,' 'suifCp^)"' (A) (B) Hinh 3: Dircmg ctjng nhiet hSp phu - khii: hdp phu N; o- 77 K ciia than hoat tinh di tu rcm-ra (A) va than hoat tinh di tir trau (B) KM Anh Tudn va Cfng sir TCHH, T.51(l), 2013 BJHD(BiplD.dVMDPonVolmrô 11 r e I" ã J \ V, PenC ™,.„.u,, (A) (B) Hinh 4: Phan bo mao quan ciia than hogt linh di lir rom-rg (A) va than hogt tinh di lir trlu (B) So sanh vdi cac vgt li^u than hogt tinh dS cdng bd nhu than gao dira SRET = 800 m^/g deu thly di?n tich be mgt ciia hai logi than hogt tinh tir ram-rg va trau cd sy tang len, nguyen nhan gay tang di^n tich be mat la la vi mao quan vat li^u chiem ban 90% tdng the lich mao quan Tuy nhien sy cd mat ciia ham lugng Silic cao than boat tinh tir trau (3,05%) da iam giam dipn tich be mgt ciia than so vdi than boat tinh di tir ram-ra, iam thay ddi dudng kinh mao quan trung binh (1,9-3,0 nm) va tdng the tich mao quan ciia than hogt tinh (0,852-1,204 cmVg) Bdng cac thdng so dac trung ciia than boat ti'nh Than boat tinh lir rom-ra Than boat tinh tir trau Dien tich be mat (BET-m'/g) 2506 1660 The tich vi mao quan (cm"'/g) 1,070 0,728 The tich mao quan meso (cmVg) 0,134 0,124 Tdng the tich mao quan (cmVg) 1,204 0,852 Dudng kinh mao quan (nm) 1,9-2,2 2,0-3,0 Thdng sd Sy thay doi di?n tich be mgt, clu true Id xdp va sy phan bd Id lam anh hudng den tinh chat hap phy cua than boat tinh, vi vgy chiing tdi tiln hanh nghien cuu kha nang hip phy cua than hogt linh 3.3 Nghien ciru kha nang hap phu cua than ho^t tinh De danh gia kha nang hap phy cua vgt li$u chiing tdi lien hanh khao sat kha nSng hap phy cua than hogt ti'nh che tgo dugc di tir ram-rg than hogt linh di tir trau va than hogt linh thucmg mgi-lhan gao dira (GD-I) doi vdi cac dung mdi hiru ca dgc hgi dl bay hai: m-xylen (dung mdi khdng phan eye) va axeton (dung mdi phan eye) Nhu chung ta da biet m-xylen la mgt dung mdi thudng dugc diing de pha son nhien cd the gay dgc hgi gay anh hudng xau den sire khoe ngudi Vi?c xu- ly dung mdi mxylen cac nha may san xuat son, cac phan xudng son old, xe may, cac thilt bj cung nhu cac dung mdi axeton, isopropanol cac phan xudng che tgo linh ki^n dien tu, nha may in bang viec sii dung than hogt tinh cd tinh cap thiet va thyc lien cao 3.3.1 Hdpphg m-xylen Hinh trinh bay dung lugng hap phy m-xylen theo thdi gian tren than hogt tinh gao dira (GD-1), than hogt tinh tir trau va than hogt linh tir ram-ra Tir hinh ta thly vgt li?u than boat linh lir rom-ra va than hogt tinh lir trlu cd toe dg hip phy ban dau nhanh hap phy h^ thdng vi mao quan cua vat li?u, dd than hogt tinh gao dira cd h? thdng vi mao quan thap han vgy loc dg hip phy ban dau chgm va dung lugng hap phy dan den bao boa thdi gian tang So sanh dung lugng hap phy bao hda, cd the nhgn thly trinh ty dung lugng hap phy m-xylen tren cac vat ligu nhu sau: than boat linh tir rcrm (-94%) > than hogt tinh tir trau (-80%) > than hogt tinh gao dira (GD-I) (-43%) Sd di than hogt tinh tong hgp tir rom-rg cd dung Iugng hem than boat tinh tir trau la dl?n tich be m^t Idn han 3.3.2 Hdp phy axeton Tir hinh the hi^n dung lugng hip axeton theo thai gian tren cac vgt Ii?u MCM-4I, than boat tinh tir ram-ra va than hogt tinh tir trlu, ta co the nhgn TCHH, T 51(1), 2013 Nghien ciru dieu che than hogt tinh Than liof I llnh nr roni i f Hinh 6: Dung lugng hap phy m-xylen theo Ihdi gian tren than hogt tinh tir ram-rg, than hogt linh tir trau va than hogt tinh gao dira (GD-1) Hinh 7: Dung lugng hap phy axeton theo thai gian tren cac vgt lipu MCM-41, than boat tinh tir ram-ra va than hogt linh lir trau thay vat lieu than hogt tinh tir ram va than boat tinh tir trau cd tdc dg bap phu ban dau nhanh ban hln so vdi MCM-41(72% ddi vdi than hoat linh tir rom-ra, 60% vdi than hogt tinh tir trau va 50% ddi vdi MCM-41) Khi keo dai thdi gian hip phu, dung lugng hip phy tang tir 72% len 93% ddi vdi than hoat tinh tir ram va tang tir 60% len 70% vdi than hoai tinh tir trlu kbi MCM-41 lang tir 50% len 71% Nhu vgy than boat tinh lir rom-rg cd dung lirgng hip phy axeton cao han so vdi MCM-41 Tuy nhien ddi vdi than boat linh tir trlu ta thay dung lirgng hip phy nhd ban MCM-41, nguyen nhan la MCM-41 mao quan trung binh chiem kha ldn vay thdi gian tang len dung lugng hap phu ciia MCM-41 cung tang len Tdm lai than boat tinh tur ram-rg dung lugng hap phu cao hon bin so vdi than hoat linh thuong mai hoac MCM-41 Dung lirgng hip phu dung mdi hiru ca ddc hai ciia than hoat tinh ram-ra dgt gia trj cao (91-93%) Ddi vdi than hoat tinh di tir trlu dung lugng hap phu tuang dtrong vdi MCM-41 va thlp ban so vdi than boat tinh tir rom-rg (70% vdi than hogt tinh tir trau va 72% vdi MCM-41) Dung lugng hip phu cao ciia logi vgt lieu dugc ly giai la be mat rieng ldn dudng kinh mao quan nam khoang chuyen tiep gi&a vi mao quan va mao quan trung binh kich thude nano nen thugn lgi cho viec hap phy Qua nghien ciiu dac trung hinh thai ciia cac chat hap phy bang cac phuang phap hda ly hien dgi nhu SEM, BET da xac djnh dugc than boat tinh cd dien lich bl mat ldn (2506 mVg ddi vdi than boat tinh tir ram-ra va 1660 m'g vdi than hoat tinh lir trau), cd till lich xop ldn (0,825-1,204 cmVg), ca hai loai than hogt tinh che tao dugc deu cd phan bd mao quan dong dlu, kich thudc 1,9-2,2 nm vdi than boat tinh tir ram-rg va 2,0-3,0 nm vdi than hoat tinh tir trau \ Than boat linh tii ram-rg cd tdc va dung lugng hip phy (91-93%) cao ban so vdi than boat tinh tir trlu (70-80%i) ddi vdi cac dung mdi hiru ca phan cue (axeton) va khdng phan eye (m-xylen) Diiu md kha nang, trien vpng irng dung cao xir ly mdi trudng cua loai vat lieu mdi KET LUAN Da cdng vi$c che tgo than hogt linh tir ngudn phe thai ndng nghiep ram-ra, trau Bang phuang phap tan xa nang lugng EDX da chiing minh dugc sy tdn tai cua ham lugng cac kim logi, va su cd mat ciia cua ham lugng silic 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andmechanismof removal of methylene blue by adsorption on various carbons-a comparative study Dyes Pigments, L 25-40 (2001) 28 M J Martin A Artola, M D Balaguer, M Rigola Activated carbons developed from surplus sewage sludge for the removal of dyes from dilute aqueous solution, Chem Eng, J., 94, 231 -239 (2003) Lien he: Vu Anh Tuan Vipn Hda hgc, Vien Han lam Khoa hgc va Cdng nghp Vipt N a m 18 Hoang Q u d e Vipt, Cau Giay, Ha Ngi Email: vuanhluan.vasl@gmail.com ... ligu nhu sau: than boat linh tir rcrm (-94%) > than hogt tinh tir trau (-80%) > than hogt tinh gao dira (GD-I) (-43%) Sd di than hogt tinh tong hgp tir rom-rg cd dung Iugng hem than boat tinh... tren than hogt tinh tir ram-rg, than hogt linh tir trau va than hogt tinh gao dira (GD-1) Hinh 7: Dung lugng hap phy axeton theo thai gian tren cac vgt lipu MCM-41, than boat tinh tir ram-ra va than. .. lir rom-rg (A) va than hogt tinh di lir trlu (B) So sanh vdi cac vgt li^u than hogt tinh dS cdng bd nhu than gao dira SRET = 800 m^/g deu thly di?n tich be mgt ciia hai logi than hogt tinh tir