NGHIÊN CỨU BIẾN TÍNH BENTONIT CỔ ĐỊNH VÀ ỨNG DỤNG TRONG XÚC TÁC – HẤP PHỤ

I HC HU TRNG I HC S PHM NGUYN Lấ M LINH NGHIấN CU BIN TNH BENTONIT C NH V NG DNG TRONG XC TC HP PH CHUYấN NGNH: HểA Lí THUYT V HểA Lí M S: 62.44.01.19 TểM TT LUN N TIN S HểA HC Hu, 2016 Cụng trỡnh c hon thnh ti Khoa Húa, trng i hc S phm, i hc Hu Ngi hng dn khoa hc: GS TS Nguyn Hu Phỳ Gii thiu lun ỏn 1: Gii thiu lun ỏn 2: Gii thiu lun ỏn 3: Lun ỏn s c bo v ti Hi ng chm lun ỏn tin s cp hp ti Vo hi ngy thỏng nm 2016 DANH MC CC CễNG TRèNH KHOA HC CễNG B LIấN QUAN N LUN N Nguyen Le My Linh, Nguyen Thi Thuc Nhi, inh Quang Khieu, Nguyen Huu Phu (2011), Modification of Co Dnh bentonite with cetyltrimethylammonium bromide by ion exchange and sonication assisted ion exchange methods, Tp Húa hc, 49 (5AB), tr.715-720 Nguyen Le My Linh, inh Quang Khieu, Nguyen Huu Phu (2011), Removal of phenol from aqueous solution by cetyltrimethylammonium functionalized bentonite, Tp Húa hc, 49 (5AB), tr.95-101 Nguyen Le My Linh, Nguyen Thi Thuc Nhi, Tran Xuan Mau, Dinh Quang Khieu, Nguyen Huu Phu (2013), Synthesis of Fe-CTAB-bentonite complexes from Co Dinh bentonite by ion exchange and hydrothermal assisted ion exchange methods, Tp khoa hc i hc Hu, 84 (6), tr 55-63 Nguyn Lờ M Linh, Dng Tun Quang, inh Quang Khiu, Nguyn Hu Phỳ (2015), Nghiờn cu tng hp Al-bentonite C nh bng phng phỏp trao i ion, Tp Xỳc tỏc v Hp ph, (4), tr 62-69 Nguyn Lờ M Linh, Nguyn Th Thanh Lai, Dng Tun Quang, inh Quang Khiu, Nguyn Hu Phỳ (2015), Nghiờn cu s hp ph As(V) dung dch nc trờn vt liu FeCTAB-bentonite, Tp Xỳc tỏc v Hp ph, (4), tr 70-77 Nguyn Lờ M Linh, Hong Vn c, Dng Tun Quang, Lờ Th Hũa, inh Quang Khiu, Nguyn Hu Phỳ (2015), Nghiờn cu phn ng benzyl húa p-xylene bng benzyl chloride trờn xỳc tỏc Fe-bentonite, Tp Húa hc, 53 (3E12), tr.213-217 Nguyn Lờ M Linh, Hong Vn c, Dng Tun Quang, Lờ Th Hũa, inh Quang Khiu, Nguyn Hu Phỳ (2015), Nghiờn cu s hp ph As(V) dung dch nc trờn vt liu Al-bentonite v AlCTAB-bentonite, Tp Húa hc, 53 (3E12), tr.296-302 Nguyn Lờ M Linh, Nguyn Th Anh Th, Dng Tun Quang, inh Quang Khiu, Nguyn Hu Phỳ (2015), Nghiờn cu ng hc v ng nhit hp ph phenol trờn vt liu bentonite bin tớnh, Tp Húa hc, 53 (3E12), tr.303-309 Nguyn Lờ M Linh, Nguyn Th Thanh Lai, Dng Tun Quang, inh Quang Khiu, Nguyn Hu Phỳ (2015), Nghiờn cu s hp ph As(V) dung dch nc trờn vt liu Fe-bentonit, Tp Húa hc, 53 (3), tr.367-373 M U Lý chn ti Bentonit vi thnh phn ch yu l sột smectit vi cu trỳc lp 2:1, cú cu trỳc mao qun, b mt riờng, dung lng trao i ion ln, bn c hc v húa hc cao nờn nú c s dng lm xỳc tỏc cỏc phn ng húa hc, cht hp ph, cht trao i ion, cht mang ci thin c tớnh, cht lng ca bentonit nhm m rng ng dng ca chỳng, cỏc nghiờn cu trung vo vic bin tớnh bentonit vi nhiu k thut khỏc Cỏc hng nghiờn cu trờn th gii cú th k l: (i) tng hp bentonit tr chng (pillared bentonite) bng cỏc kim loi, oxit kim loi vi cỏc phng phỏp khỏc [46, 48, 98, 115, 145, 150], (ii) tng hp vt liu sột hu c bng cỏch hu c húa bentonit [61, 62, 65, 66, 75, 82], (iii) tng hp vt liu polyme/bentonit nanocomposit [81, 86, 87] Trong ú ỏng quan tõm nht l vt liu sột chng tng hp bng cỏch chốn ion Keggin Al13, Fe13, vo khong gia cỏc lp sột v sột hu c u im ca sột chng l din tớch b mt v th tớch mao qun ln nờn tớnh cht hp ph v xỳc tỏc ci thin ỏng k so vi bentonit cha bin tớnh [141], nhng b mt a nc nờn sột chng hp ph yu cỏc hp cht hu c ụ nhim Trong ú, sột hu c li hp ph tt cỏc cht hu c Xut phỏt t ý tng kt hp hai loi vt liu ny m loi vt liu mi i chốn ng thi c ion kim loi ln cht hu c gi l sột vụ c-hu c (inorganicorganic clay) Tuy nhiờn, cho n cũn ớt cụng b v loi vt liu ny v mt tng hp cng nh ng dng Nc ta cú ngun ti nguyờn bentonit rt phong phỳ c phỏt hin nhiu ni vi tr lng ln: C nh - Thanh Húa, Di Linh Lõm ng, Tuy Phong - Bỡnh Thun Tuy nhiờn, bentonit nc ta mi c khai thỏc phm vi nh v ch yu c s dng lm vt liu gm, vt liu xõy dng, x lý mụi trng Do hm lng smectit bentonit nc ta tng i thp nờn khụng th s dng trc tip mt s ngnh cụng ngh cao m cn phi lm giu v bin tớnh cu trỳc, b mt vt liu Mc dự bentonit v cỏc sn phm bin tớnh t nú ó c quan tõm nghiờn cu nhiu trờn th gii, nhng Vit Nam vic nghiờn cu bin tớnh bentonit C nh mt cỏch cú h thng v ng dng hiu qu ca cỏc loi vt liu ny hp ph v xỳc tỏc cũn rt hn ch Ngoi ra, vi s phỏt trin vt bc ca khoa hc v cụng ngh ó thỳc y cỏc ngnh cụng nghip phỏt trin mnh,bờn cnh nhng thnh tu t c, xó hi ang phi i mt vi ụ nhim mt s ngnh cụng nghip to Trong ú, ỏng chỳ ý l cỏc cht thi t cỏc nh mỏy lc húa du, dt nhum, dc phm, cht do, sn, m phm, thuc tr sõu Hu qu l cỏc ngun nc b ụ nhim bi cỏc cht hu c khú phõn hy sinh hc (phenol v cỏc dn xut, thuc nhum ) v kim loi nng ( Cd, Pb, As, Hg ) ci thin tỡnh trng ụ nhim cỏc cht hu c, kim loi nng , hng nghiờn cu ca cỏc nh khoa hc l s dng vt liu thiờn nhiờn cú giỏ thnh thp, d kim nh bentonit v bentonit bin tớnh lm cht hp ph Do ú, vic s dng vt liu bin tớnh bentonit Vit Nam s em li nhng li ớch kinh t rt to ln Vỡ nhng lớ trờn, chỳng tụi chn ti: Nghiờn cu bin tớnh bentonit C nh v ng dng xỳc tỏc - hp ph Mc ớch v nhim v nghiờn cu Nghiờn cu tng hp vt liu bentonit hu c, bentonit vụ c v bentonit lai hp hu c vụ c Vt liu tng hp c ng dng hp ph As(V), phenol v xỳc tỏc cho phn ng benzyl húa p-xylen Nhng úng gúp mi ca lun ỏn - Nghiờn cu h vt liu smectit mi Vit Nam ú l nontronit C nh Thanh Húa - Ln u tiờn, c ch, ng hc v nhit ng hc ca cỏc quỏ trỡnh hp ph As(V), phenol trờn vt liu bentonit bin tớnh ó c tho lun mt cỏch chi tit So vi cỏc vt liu bentonit bin tớnh khỏc hin nay, vt liu Fe-bentonit, Al-bentonit c cụng b cú dung lng hp ph As(V) cao hn - Vt liu Fe-bentonit tng hp l cht xỳc tỏc tt cho phn ng alkyl húa cỏc hp cht thm vi chn lc v chuyn húa cao im ni bt ca lun ỏn l xỏc nh c mụ hỡnh LangmuirHinshewood phự hp vi mụ hỡnh ng hc ca phn ng benzyl húa p-xylen trờn xỳc tỏc Fe-bentonit - Cỏc quỏ trỡnh hp ph v xỳc tỏc u xy trờn cỏc tõm Fe3+ v Al3+ c phõn tỏn cu trỳc ca nontronit v nontronit c bin tớnh bng CTAB Nhit ng hc v ng hc ca cỏc quỏ trỡnh u xy trờn cỏc tõm hot ng trờn b mt ca thnh mao qun trung bỡnh v b mt ngoi (gúc, g, cnh, ) ca vt liu nontronit B cc ca lun ỏn Ni dung lun ỏn gm 140 trang, 42 bng, 86 hỡnh, 14 s , 152 ti liu tham kho B cc ca lun ỏn nh sau: M u: trang Chng Tng quan ti liu: 30 trang Chng Ni dung, phng phỏp nghiờn cu v thc nghim: 19 trang Chng Kt qu v tho lun: 84 trang Chng Kt lun cỏc kt qu t c: trang CHNG TNG QUAN Trong phn ny tỏc gi ó trỡnh by tng quan cỏc sau: 1.1 Gii thiu v vt liu khoỏng sột 1.2 Sột hu c 1.3 Khoỏng sột tr chng 1.4 Hp ph asen trờn vt liu bentonit v bentonit bin tớnh 1.5 Hp ph phenol trờn vt liu bentonit v bentonit bin tớnh 1.6 Phn ng benzyl húa Friedel-Crafts cỏc hp cht thm trờn cỏc xỳc tỏc khỏc CHNG NI DUNG, PHNG PHP NGHIấN CU V THC NGHIM 2.1 MC TIấU Tng hp c vt liu bentonit hu c, bentonit vụ c, bentonit lai hp hu c - vụ c ng dng hp ph As(V), phenol v xỳc tỏc cho phn ng benzyl húa p-xylen 2.2 NI DUNG - Tinh ch bentonit C nh, nghiờn cu thnh phn, cu trỳc v tớnh cht ca bentonit C nh - Tng hp vt liu CTAB-bentonit, Fe-bentonit, Fe-CTAB6 bentonit, Al-bentonit v Al-CTAB-bentonit - Nghiờn cu s hp ph As(V) dung dch nc ca vt liu bentonit bin tớnh: la chn cht hp ph, nh hng ca pH v c ch hp ph, ng hc v nhit ng hc quỏ trỡnh hp ph - Nghiờn cu s hp ph phenol dung dch nc ca vt liu bentonit bin tớnh - Nghiờn cu tớnh cht xỳc tỏc ca vt liu bentonit bin tớnh phn ng alkyl húa Friedel-Crafts 2.3 PHNG PHP NGHIấN CU 2.3.1 Cỏc phng phỏp c trng vt liu: Nhiu x tia X (XRD), ph hng ngoi (IR), hin vi in t quột (SEM), tỏn x nng lng tia X (EDX), ng nhit hp ph - kh hp ph nit 77K, phõn tớch nhit (TG-DTA) 2.3.2 Cỏc phng phỏp phõn tớch nh lng: Quang ph hp th nguyờn t (AAS), ph t ngoi - kh kin (UV-Vis), sc ký khớ kt hp vi ph (GC-MS) 2.3.3 Nghiờn cu ng nhit hp ph: s dng hai mụ hỡnh ng nhit hp ph: Langmuir v Freundlich 2.3.4 Nghiờn cu ng hc hp ph: s dng mụ hỡnh ng hc hp ph biu kin bc v bc 2.4 THC NGHIM - Tinh ch bentonit C nh - Tng hp vt liu CTAB-bentonit - Tng hp vt liu Fe-bentonit v Fe-CTAB-bentonit - Tng hp vt liu Al-bentonit v Al-CTAB-bentonit - Nghiờn cu s hp ph As(V) dung dch nc trờn vt liu Fe-bentonit, Fe-CTAB-bentonit, Al-bentonit, Al-CTAB-bentonit - Nghiờn cu s hp ph phenol dung dch nc trờn vt liu CTAB-bentonit, Fe-CTAB-bentonit, Al-CTAB-bentonit - Nghiờn cu phn ng alkyl húa Friedel-Crafts trờn xỳc tỏc Fe-bentonit Chng KT QU V THO LUN 3.1 THNH PHN, CU TRC V TNH CHT CA BENTONIT C NH 3.1.1 Thnh phn húa hc v cu trỳc ca bentonit C nh Qua kho sỏt thnh phn húa hc v cu trỳc ca bentonit C nh tinh ch, chỳng tụi cú kt lun sau: bentonit C nh (Thanh Húa) l mt dng sột lp smectit 2:1 thuc nhúm nontronit, cú cụng thc húa hc ca n v cu trỳc c bn nh sau: X (Si7,9Al0,1)IV (Fe3,02Al0,44Mg0,54)VI O20(OH)4 (3.6) 0,64 3.1.2 Mt s tớnh cht húa lý c trng ca bentonit C nh 3.1.2.1 Ph XRD Sau tinh ch, thch anh v cao lanh ó b loi b gn nh hon ton, ch cũn li ch yu l nontronit (hỡnh 3.1) Cỏc kt qu hỡnh 3.2 chng t rng bentonit C nh cú cu trỳc hỡnh hc kiu smectit, gia cỏc lp sột cú khong cỏch (14,4 - 9,6 ) Khong cỏch ú to mng vi mao qun ca sột, c trng cho vt liu nontronit (001) Q 15,4 K 10 K MMT Q BCĐ -TN 20 30 40 50 60 9,6 N-600 9,9 N-400 14,4 C- ờng độ (tù y chọn) (001) N-2d 14,3 C- ờng độ (tù y chọn) 14,4 N 10 Theta (độ) N 20 30 40 50 60 Theta (độ) Hỡnh 3.1 Gin XRD ca Hỡnh 3.2 Gin XRD ca cỏc mu BC-T, N-2d v N cỏc mu N trc v sau nung 3.1.2.2 Ph hng ngoi IR Cỏc pic hp th c trng ph IR ca mu N c trỡnh by bng 3.5: Bng 3.5 Cỏc pic hp th c trng ph IR ca mu N Dao ng Al-FeOH Fe-FeOH H-OH Si-O Fe-FeOH (bin dng) Al-FeOH IR (cm-1) 3549 3414 1638 964 1111 816 675 3.1.2.3 ng nhit hp ph N2, 77K Tớnh cht b mt v cu trỳc mao qun ca bentonit C nh c nghiờn cu bng phng phỏp hp ph - kh hp ph N2 77K (hỡnh 3.4) Sau tinh ch, vt liu giu sột smectit 2:1 hn, tớnh cht b mt ca N c ci thin hn (SBET, Smic, Sext v Vp u tng lờn)) SBET ca bentonit trc v sau tinh ch c xỏc nh l 70,26 v 114,44 m2/g 0,06 dV/dD (cm g nm ) BCé-TN N BCé-TN N -1 120 0,04 -1 L- ợ ng hấp phụ (cm /g, STP) (b) (a) 150 90 60 0,02 30 0,00 0,0 0,2 0,4 0,6 0,8 10 15 20 Đ - ờng kính mao quản (nm) 1,0 o p suất t- ơng đối (P/P ) Hỡnh 3.4 ng ng nhit hp ph - kh hp ph nit (a) v ng phõn b mao qun (b) ca cỏc mu BC-TN v N 3.1.2.4 im in tớch khụng Kt qu pHPZC ca BC-TN, N xỏc nh c ln lt l 6,9; 7,3 Nh vy, s tinh ch ó loi b cỏt thch anh, cao lanh v l b mt ngoi nhiu nhúm chc Al-OH v Fe-OH hn, nờn pHPZC ca N ln hn so vi BC-TN 3.1.2.5 Dung lng trao i ion Bng 3.6 Giỏ tr CEC ca cỏc mu bentonit C nh trc v sau tinh ch Mu BC-TN N-2d N CEC (ml/100g) 52,4 60,7 73,3 3.1.2.6 Phõn tớch nhit TG-DTA ng cong TG v DTA ca mu bentonit trc v sau tinh ch (hỡnh 3.6) tng t im khỏc bit l mu N xut hin pic thu nhit 778 oC (quy cho quỏ trỡnh tỏch nhúm -OH ca lp aluminosilicat), cũn mu BC-TN khụng thy xut hin pic thu nhit rừ rng iu ny chng t bentonit tinh ch thnh phn ch yu l NONT nờn nhit phỏ v cu trỳc NONT thp hn TG mg 6,0 DTA uV (a) (b) -10 5,6 N N -20 5,2 -30 BCé-TN BCé-TN -40 4,8 -50 0 200 400 600 800 200 400 600 1000 800 1000 o Nhiệt độ ( C) o Nhiệt độ ( C) Hỡnh 3.6 Gin TG v DTA ca mu BC-TN v N 3.2 TNG HP VT LIU CTAB-BENTONIT (001) 1,5C1N 0,8C1N 0,4C1N 0,1C1N 1,5C3N/S 1,0C3N/S C- ờng độ (tù y chọn) C- ờng độ (tù y chọn) 1,0C1N (001) 0,4C1N/S 0,5C2N/S 0,4C2N/S 0,5C3N/S N 10 20 30 40 50 N 60 Theta (độ) 10 20 30 40 Theta (độ) Hỡnh 3.8 Gin XRD ca cỏc mu CTAB-bentonit tng hp theo phng phỏp trao i ion vi nhng hm lng CTAB khỏc Hỡnh 3.9 Gin XRD ca cỏc mu CTAB-bentonit tng hp theo phng phỏp trao i ion cú s h tr ca siờu õm vi nhng hm lng CTAB khỏc 10 normal condition with different molar ratio nOH / nFe hydrothermal condition with different molar ratio nOH / nFe TG and DTA curves of N and Fe-bentonite samples are presented in Fig 3.20 TG mg (a) DTA uV (b) 1,5FeNT N 1,5FeN 0,3FeN N -20 1,5FeN 1,5FeNT -40 0,3FeN 200 400 600 800 200 400 600 800 o o Temperature ( C) Temperature ( C) Figure 3.20 TG (a) and DTA (b) curves of N and Fe-bentonites The results shows that there is the intercalation of polyhydroxy-Fe or polyoxo-Fe cations into bentonite The more the molar ratio nOH / nFe in the preparation solution increases, the less Fe content intercalates into the bentonite Fig 3.21 shows nitrogen adsorption-desorption isotherms of N, 0,3FeN and 1,5FeN The specific surface areas SBET are increased after intercalating inorganic cations into interlayer spaces of NONT, from 114,44 ( N) to 146,07 m2/g (0,3FeN) and to 150,96 m2/g (1,5FeN) 120 N 0,3FeN 1,5FeN -1 Volume adsorbed (cm g ,SPT) 150 90 60 30 0,0 0,2 0,4 0,6 0,8 1,0 o Relative pressure (P/P ) Figure 3.21 N2 adsorption desorption isotherms of N, 0,3FeN and 1,5FeN 3.3.2 Synthesis of Fe-CTAB-bentonite materials The results indicate that the synthesis of Fe-CTAB-bentonite samples in hydrothermal condition doesnt improve the properties of these materials than that in normal condition (Fig 3.22, 3.23) 42 (001) (001) 2,0FeCN 2,0FeCT 1,5FeCT Intensity (cps) Intensity (cps) 1,5FeCN 0,8FeCN 0,3FeCN 0,8FeCT 0,3FeCT 0,4C1N 0,4C1N N N 10 20 30 40 50 60 Theta (deg.) 10 20 30 40 50 60 Theta (deg.) Figure 3.22 XRD patterns of Fe- Figure 3.23 XRD patterns of FeCTAB-bentonite samples synthesized in hydrothermal condition with different molar ratio nOH /nFe CTAB-bentonite samples synthesized in normal condition with different molar ratio nOH /nFe The XRD results show that 1,5FeCN sample has the biggest d001 value The samples with the molar ratio nOH /nFe lower or greater than 1,5 have smaller d001 values and lower intensity of d001 peaks than that synthesized with the molar ratio nOH /nFe 1,5 This can be explained that Fe3+ and Fe(OH)4- ions intercalate into the layers and cause the dispersion effect of smectite particles of NONT at the low pH Fig 3.27 presents nitrogen adsorption-desorption isotherms of N, 0,4C1N, N 0,4C1N 0,3FeCN, 1,5FeCN The 0,3FeCN 1,5FeCN specific surface areas of two samples 0,3FeCN (4,88 m2/g) and 1,5FeCN (16,56 m2/g) are much smaller than that of purified bentonite Relative pressure (P/P ) 120 -1 Volume adsorbed (cm g ,SPT) 150 90 60 30 0,0 0,2 0,4 0,6 0,8 1,0 o Figure 3.27 N2 adsorption desorption isotherms of N, 0,4C1N, 0,3FeCN and 1,5FeCN 43 3.4 SYNTHESIS OF Al-BENTONITE BENTONITE MATERIALS AND Al-CTAB- 3.4.1 Synthesis of Al-bentonite materials Effect of factors such as bentonite concentration, molar ratio nOH /n Al and aging time of pillaring solution on Al-bentonite structure was studied and we reach some results below: - In order to intercalate Al13 Keggin-ion species into nontronite interlayer spaces, the molar ratio nOH /n Al is 2,0 and 2,4, bentonite nOH /n Al 2,4 (2,4Al1N) 150 N 2Al1N 2,4Al1N 120 Fig 3.32 shows nitrogen adsorptiondesorption isotherms of N, Al-bentonite samples synthesized in conditions: bentonite concentration of 1,0 %, aging time of pillaring solution of day, nOH /n Al 2,0 (2Al1N), Volume adsorbed (cm /g, STP) concentration is 1,0 % - The aging time of pillaring solution doesnt exceed days If lengthening the time, Al13 Keggin ions will be decomposed into smaller species 90 60 30 0,0 0,2 0,4 0,6 0,8 1,0 o Relative pressure (P/P ) 3.32 N2 adsorption desorption isotherms of N, 2Al1N Figure and 2,4Al1N The specific surface areas of two samples 2Al1N and 2,4Al1N are 152 and 170,13 m2/g, respectively The increase of the specific surface areas of Al-bentonite samples is due to the increase of specific surface area of micropores from 44,72 m2/g (N) to 92,84 m2/g (2Al1N) and to 119,61 m2/g (2,4Al1N) 3.4.2 Synthesis of Al-CTAB-bentonite materials From the XRD results (Fig 3.37, 3.38), we reach a conclusion: the basal spacings d001 of these materials increases when intercalatting CTAB species and Al13 cations into nontronite interlayer spaces, Al44 CTAB-bentonite structures depend on both the intercalation methods and CTAB content inserting to nontronite If Al13 cations are intercalated after CTAB (method 1), the obtained Al-CTAB-bentonite materials are shown to have the orderer structure than those synthesized by simultaneously intercalating both CTAB and Al13 cations into nontronite (method 2) Due to the presence of CTAB in Al-CTAB-bentonite materials, the nontronite structures can not be easily collapsed (001) (001) 19,8 19,9 Intensity (cps) 1,0CN2Al 19,9 0,8CN2Al 18,2 0,4CN2Al Intensity (cps) 1,5CN2Al 19,4 2Al1,0CN 19,1 2Al0,8CN 18,8 2Al0,4CN 15,4 14,4 14,4 N 10 20 30 40 50 N 14,4 0 2Al0,1CN 0,1CN2Al 60 10 20 30 40 Theta (deg.) Theta (deg.) Figure 3.38 XRD patterns of Al-CTAB-bentonite samples synthesized by method with different content of CTAB Figure 3.37 XRD patterns of Al-CTAB-bentonite samples synthesized by method with different content of CTAB 30 Volume adsorbed (cm /g, SPT) The nitrogen adsorption and desorption isotherms of 0,4CN2Al and 0,8CN2Al samples are shown in Fig 3.43 Table 3.15 Structural parameters of 0,4CN2Al and 0,8CN2Al 0,4CN2Al 0,8CN2Al SBET Vp Samples (m2/g) (cm3/g) 0,4CN2Al 5,07 0,028 0,8CN2Al 10,07 0,11 20 10 0,0 0,2 0,4 0,6 0,8 1,0 o Relative pressure (P/P ) Figure 3.43 N2 adsorption desorption isotherms of 0,4CN2Al and 0,8CN2Al 45 The obtained Al-CTABbentonit materials still maintain pore structure, but their specific surface areas are lower than that of purified bentonite 3.5 RECHERCHE OF ADSORPTION OF As(V) IN AQUEOUS SOLUTION ON Fe-BENTONITE, Fe-CTAB-BENTONITE, Al-BENTONITE, Al-CTAB-BENTONITE MATERIALS 3.5.1 Adsorbents selection and determination of point of zero charge of selected materials From the experimental results, 0,3FeN, 0,3FeCN, 2,4Al1N and 0,4CN2Al samples were selected for further study pHPZC of 0,3FeN, 0,3FeCN, 2,4Al1N, 0,4CN2Al samples are determined to be 3,1; 4,7; 4,8; 6,3 respectively The analytic results of the relationship of the important factors favoring the As(V) adsorption onto 0,3FeN, 0,3FeCN, 2,4Al1N and 0,4CN2Al materials show that the As(V) adsorption is essential carried out at outer surface of colloidal NONT particles (surfaces of mesopores, edges and sides of basic particles , that contain Fe and Al sites attracting As(V)), 3.5.2 Effect of solution pH and adsorption mechanisms 0,3FeN 0,3FeCN 2,4Al1N 0,4CN2Al 16 -1 qe (mg.g ) 12 4 10 pH Figure 3.46 Effect of pH on the adsorption capacity of As(V) onto 0,3FeN, 0,3FeCN samples (Co(As) = 12,98 mg/l), 2,4Al1N sample (Co(As) = 16,84 mg/l) and 0,4CN2Al sample (Co(As) = 8,46 mg/l)(T = 303K, m = 0,05 g, t = h) The Fig 3.46 reveals that the optimal adsorption was obtained in the pH 4,0 for 2,4Al1N, 0,4CN2Al samples and pH 3,0 for 0,3FeN, 0,3FeCN samples 46 Adsorption mechanisms: The recherche results indicate that the As (V) adsorption process onto 0,3FeN, 0,3FeCN, 2,4Al1N, 0,4CN2Al samples is followed by surface complexation with ligand exchange type and electrostatic interactions 3.5.3 Adsorption kinetics 3.5.3.1 Effect of contact time Experimental results indicate that the As(V) adsorption onto 0,3FeN, 0,3FeCN materials (Co(As) = 11,95 mg/l, pH = 3,0) and 2,4Al1N, 0,4CN2Al materials (Co(As) = 16,84 mg/l, pH = 4,0) at 283K, 293K, 303K and 313K is reached in 180 240 3.5.3.2 Kinetic models Parameters of pseudo-first-order and pseudo-second-order kinetic model are summarized in Table 3.18 The pseudo-second-order kinetic model is in a good agreement with the experimental value 3.5.3.3 Effect of temperature -3,5 (b) -4,0 (a) -5,0 lnk2 -4,5 lnk2 -5,5 -5,0 -6,0 -5,5 -6,5 -6,0 -7,0 -6,5 2,4Al1N R = 0,924 0,4CN2Al R = 0,900 0,3FeN R = 0,952 0,3FeCN R = 0,973 -7,5 -7,0 0,0032 -8,0 0,0033 0,0034 0,0035 -1 1/T (K ) 0,0032 0,0033 0,0034 0,0035 -1 1/T (K ) Figure 3.55 Plots of lnk2 vs 1/T for As(V) adsorption onto 0,3FeN, 0,3FeCN, 2,4Al1N and 0,4CN2Al materials From the Arrhộnius equation, we can calculate the activation energy of arsenate adsorption onto selected materials (0,3FeN (80,29 kJ/mol), 0,3FeCN (42,03 kJ/mol), 2,4Al1N (41,90 kJ/mol) and 0,4CN2Al (42,27 kJ/mol)) 47 Table 3.18 Parameters of pseudo-first-order and pseudosecond-order kinetic model of As (V) adsorption onto 0,3FeN, 0,3FeCN, 2,4Al1N, 0,4CN2Al materials at different temperature 0,3FeN T (K) 283 293 303 313 0,3FeCN T (K) 283 293 303 313 2,4Al1N T (K) 283 293 303 313 0,4CN2Al qe (tn) (mg/g) 14,38 14,42 14,42 14,44 qe (tn) (mg/g) 13,89 13,92 14,02 14,5 qe (tn) (mg/g) 18,47 20,75 20,80 21,05 T (K) qe (tn) (mg/g) 283 293 303 313 9,04 9,93 10,02 8,58 Pseudo-first-order qe (tt) k1(phỳt ) R2 (mg/g) 0,010 15,19 0,942 0,013 12,44 0,977 0,027 9,80 0,962 0,021 6,57 0,992 Pseudo-first-order k1 (phỳt- qe (tt) R2 ) (mg/g) 0,006 10,92 0,956 0,010 11,36 0,983 0,006 9,44 0,892 0,024 10,06 0,899 Pseudo-first-order qe (tt) k1 (phỳt-1) R2 (mg/g) 1,6.10-3 16,35 0,956 1,9.10-3 13,01 0,948 7,0.10-3 8,56 0,949 9,0.10-3 7,09 0,752 Pseudo-first-order k1 (phỳt- qe (tt) R2 ) (mg/g) 1,6.10-2 6,48 0,947 3,8 10-2 6,39 0,99 0,8.10-2 3,46 0,889 1,7.10-2 2,01 0,992 Pseudo-second-order -1 SE 1,85 4,55 11,81 19,57 SE 7,67 6,02 11,38 8,37 SE 19,68 19,33 30,97 33,30 k2(g/mg.phỳt) qe (tt) (mg/g) R2 -3 0,35.10 21,14 0,924 0,68.10-3 19,80 0,973 4,20.10-3 15,53 0,999 7,30.10-3 14,97 0,998 Pseudo-second-order qe (tt) k2(g/mg.phỳt) R2 (mg/g) -3 0,62.10 17,54 0,925 1,47 10-3 16,95 0,977 2,01 10-3 14,08 0,938 3,71.10-3 15,87 0,996 Pseudo-second-order k2 (g/mg.phỳt) -3 qe (tt) (mg/g) R2 1,0.10 22,22 0,984 2,9.10-3 22,22 0,998 4,2.10-3 20,83 0,992 5,8.10-3 21,28 0,996 Pseudo-second-order qe (tt) SE k2(g/mg.phỳt) R2 (mg/g) 11,20 3,8.10-3 10,10 0,992 8,65 12,2 10-3 10,42 0,998 14,49 13,5 10-3 10,00 0,990 13,89 24,6.10-3 8,77 0,999 SE 1,42 1,17 1,27 1,38 SE 1,76 1,73 3,07 1,25 SE 2,03 1,75 4,69 3,67 SE 0,71 0,92 2,12 1,29 qe (tn) is the equilibrium adsorption capacity calculated by initial concentration and equilibrium concentration qe (tt) is the equilibrium adsorption capacity calculated by kinetic equation 3.5.4 Adsorption isotherms The results indicate that the Langmuir model is appropriate to apply to the adsorption of As(V) onto selected materials The adsorption of As(V) onto modified bentonite only occurs at the outer surfaces and in the large pores of bentonite particles The As(V) monolayer adsorption capacity (qm) of 2,4Al1N, 0,3FeN, 0,4CN2Al, 0,3FeCN samples are determined to be 35,71 mg/g, 18,98 mg/g, 17,86 mg/g, 15,63 mg/g, respectively The thermodynamic parameters for the As(V) adsorption are presented in Table 3.21 48 Table 3.21 Thermodynamic parameters for the As(V) adsorption onto 0,3FeN, 0,3FeCN, 2,4Al1N and 0,4CN2Al materials 0,3FeCN 0,3FeN T (K) KL (l/mol) G (kJ/mol) 283 80913,6 -26,59 293 388085,6 -31,35 303 589620,4 -33,47 o Ho (kJ/mol) 71,23 So (kJ/mol.K) KL (l/mol) Go (kJ/mol) Ho (kJ/mol) So (kJ/mol.K) 0,347 53009,4 38788,3 -25,59 -25,74 -17,36 0,029 32618,2 -26,18 So (kJ/mol.K) KL (l/mol) Go (kJ/mol) Ho (kJ/mol) So (kJ/mol.K) 0,180 18879,8 15808,1 -23,17 -23,55 -17,95 0,019 11387,8 -23,53 0,4CN2Al 2,4Al1N T (K) 283 293 303 KL (l/mol) G (kJ/mol) 24259,1 -23,76 30559,9 52444,0 -25,16 o Ho (kJ/mol) 27,34 -27,38 The results show that the As(V) adsorption onto selected materials is spontaneous (Go < 0) in all the investigated temperature range However, we have a common rule: the As(V) adsorption onto 0,3FeN, 2,4Al1N is endothermic with the high variation of entropy and the As(V) adsorption onto 0,3FeCN, 0,4CN2Al is exothermic with the low variation of entropy 3.6 RECHERCHE OF ADSORPTION OF PHENOL RED IN AQUEOUS SOLUTION ON CTAB-BENTONITE, Fe-CTAB-BENTONITE AND Al-CTAB-BENTONITE MATERIALS 3.6.1 Adsorbents selection and determination of point of zero charge of selected materials From the experimental results, 0,8C1N, 0,8CN2Al and 1,5FeCN samples were selected for further study pHPZC of 0,8CN, 0,8CN2Al, 1,5FeCN samples are determined to be 7,1; 6,3; 5,8 respectively 3.6.2 Effect of solution pH The optimal pH for the phenol red adsorption onto modified bentonite is 3,0 (Figure 3.62) 49 -1 qe (mg.g ) 100 80 60 0,8C1N 0,8CN2Al 1,5FeCN 40 10 pH Figure 3.62 Effect of pH on the adsorption capacity of phenol red onto 0,8C1N, 0,8CN2Al and 1,5FeCN samples (Co(phenol red) = 100 mg/l, T=303K) 3.6.3 Adsorption kinetics The study results show that the pseudo-second-order model is correlated well with the experimental data on the adsorption of phenol red onto 0,8C1N, 0,8CN2Al and 1,5FeCN samples The adsorption of phenol red is taken place at the active sites located at outer surfaces and in pores formed among basic particles The activation energies of phenol red adsorption onto 0,8C1N, 0,8CN2Al, 1,5FeCN are calculated 17,82 kJ/mol, 33,87 kJ/mol, 17,52 kJ/mol, respectively 3.6.4 Adsorption isotherms The results show that the Langmuir model fits well with the experimental data The phenol red monolayer adsorption capacity (qm) of 0,8C1N, 0,8CN2Al, 1,5FeCN are 166,7 mg/g, 125,0 mg/g, 100,0 mg/g, respectively The study of determination of thermodynamic parameters for phenol red adsorption onto selected materials indicates that this adsorption is spontaneous (Go < 0), endothermic (Ho > 0) and entropy increases (So > 0) in all the investigated temperature range 3.7 RECHERCHE OF FRIEDEL-CRAFTS ALKYLATION USING Fe-BENTONITE MATERIAL AS CATALYST 3.7.1 Catalysts selection From the experimental data, 1,5FeN sample was selected for further study 50 3.7.2 Benzylation of different aromatics Table 3.28 Alkylation of different aromatics over 1,5FeN catalyst Conversion of benzyl chloride (%) Aromatic Benzene 100 Toluene 100 p-Xylene 100 Bromobenzene Product DPM (100 %) 2-MDPM (37,03 %) 4-MDPM (62,97 %) BDMB (100 %) No reaction It is evident from Table 3.28 that there are no assitant products in the benzylation of different aromatics by benzyl chloride over invertigated catalyst In addition, the alkylation over 1,5FeN catalyst shows a high selectivity and conversion 3.7.3 Factors influence on the benzylation of p-xylene 3.7.3.1 Influence of molar ratio of the reactants The results show that the conversion of benzyl chloride increases with increasing p-xylene: benzyl chloride molar ratio from 22:1 to 2:1 BC conversion (%) 100 80 2:1 3:1 6:1 22:1 60 40 20 0 20 40 60 t (min) Figure 3.72 Benzyl chloride conversion versus time using different molar ratio of p-xylene/benzyl chloride and 1,5FeN as catalyst (T = 343K, catalyst mass: 0,02 g) 51 3.7.3.2 Influence of catalyst mass The Fig 3.73 shows the conversion of benzyl chloride increases when the mass of the catalyst increases It is impotant to highlight the fact that the only product formed is the monoalkylated product BC conversion (%) 100 0,01 g 0,02 g 0,05 g 80 60 40 20 0 10 15 20 t (min) Figure 3.73 Benzyl chloride conversion versus time using different mass of 1,5FeN catalyst (T = 343K, p-xylene/benzyl chloride molar ratio of 22:1) 3.7.3.3 Influence of reaction temperature Reaction kinetics and activation energy The results show that the conversion of benzyl chloride over 1,5FeN catalyst increases by increasing the reaction temperature from 343 to 363K The paramaters of first-order kinetics are summerized in Table 3.29 Table 3.29 The paramaters of first-order kinetics for the benzylation of p-xylene over 1,5FeN catalyst Temperature (K) k' (min-1) k (g-1.min-1) R2 343 0,142 7,10 0,919 353 0,842 42,1 0,959 363 1,448 72,4 0,944 It can be seen from the Table 3.29 that the first order rate constant increases with temperature The activation energy was calculated by Arrhộnius equation was 120,76 kJ/mol 52 3.7.4 Investigation of heterogeneous nature of catalyst and recycling of catalyst 3.7.4.1 Investigation of heterogeneous nature of catalyst Fig 3.77 shows the conversion of benzyl chloride versus time using with 1,5FeN catalyst 1,5FeN catalyst and after removing 1,5FeN catalyst After 60 minutes of the reaction, the conversion of without 1,5FeN catalyst benzyl chloride remains hot filter almost unchanged after the removal of the catalyst This t (min) is proof to conclude that a heterogeneous catalytic Hỡnh 3.77 Conversion of benzyl reaction is taking place over chloride versus time using 1,5FeN 1,5FeN catalyst catalyst and after removing 1,5FeN catalyst BC conversion (%) 100 80 60 40 20 0 10 20 30 40 50 60 3.7.4.2 Recycling of catalyst The study of recycling catalyst indicates that the reaction over 1,5FeN catalyst is first run to the conversion of benzyl chloride of 94 % and second run to the conversion of 87 % These results show the high possibility of regeneration and reusability of 1,5FeN catalyst 3.7.5 Reaction kinetics for benzylation of p-xylene over 1,5FeN catalyst 3.7.5.1 Adsorption of benzyl chloride and p-xylene onto 1,5FeN catalyst The results show that the catalyst absorps both benzyl chloride and p-xylene at the same time The adsorption capacity of benzyl chloride is higher than that of p-xylene 3.7.5.2 Proposing kinetic model for benzylation of p-xylene over 1,5FeN catalyst From the experimental results, kinetics should be modelled considering LangmuirHinshelwood mechanism This leads to the equation of pseudo-first order of benzylation of p-xylene if an excess of p-xylene is used 53 C Bo (3.49) m.k t CB where CoB and CB are concentrations of benzyl chloride respectively at inital time and t time, k (mint-1) is rate constant, m is mass of catalyst, t is reaction time (min) 3.7.6 Proposed mechanism (i) Activation of p-xylene and benzyl chloride by redox sites ln CH3 CH3 H H + -Fe O - F - O e- - CH3 CH3 Cl n + Cl Fem+ n + Fe(m-n)+ CH2+ Cl n n Fe(m-n)+ + + Fem+ n Cl + n Cl n Cl (ii) Reaction forming BDMB CH3 CH H Fe - -O+ - CH2 + + H+ + -Fe O - CH3 CH Scheme 3.5 Proposed mechanism for the benzylation of p-xylene over 1,5FeN catalyst 54 CONCLUSIONS By purification of bentonite and by different methods of characteristics such as XRD, IR, EDX, TG-DTA for the first time in Viet Nam, Co Dinh bentonite is demonstrated is a type of 2:1 silicate layers of smectite which is composed of nontronite: iron rich, aluminium poor This material contains a lot of Fe3+, so it is favorable to synthesize catalysts, adsorbents The chemical formula of its basic structural unit is presented as below: X (Si7,9Al0,1)IV (Fe3,02Al0,44Mg0,54)VI O20(OH)4 0,64 Thesis investigated in detail the synthesis of organic bentonite (CTAB-bentonite), inorganic bentonite (Fe-bentonite, Al-bentonite) and organic-inorganic hybrid bentonite (Fe-CTAB-bentonite, AlCTAB-bentonite) by ion-exchange method The results of materials characterization show that depending on the synthesis conditions, the Fe, Al oligomers ((Fe3+)x, (Al3+)y, Fe13m+, Al13n+, where x, y, m, n are coefficients) are intercalated into NONT, which made the basal spacing d001 increase The obtained inorganic bentonites have pore structures and high specific surface areas (1,5FeN: 150,96 m2/g, 2,4Al1N: 170,13 m2/g) For the organic-inorganic hybrid bentonite materials, both organic and inorganic cations insert into the interlayer spaces of nontronite, so the d001 values increase, but their specific surface areas and pore volumes are significantly lower than those of purified bentonite due to the covering of micropores by CTAB Thesis investigated in detail the factors influenting the adsorption of As (V) onto inorganic bentonite and organic-inorganic hybrid bentonite materials from aqueous solution such as pH, As (V) inital concentration, temperature The optimal adsorption was obtained in the pH 4,0 for Fe-bentonite and Fe-CTAB-bentonite materials and pH 3,0 for Al-bentonite v Al-CTAB-bentonite materials The As(V) monolayer adsorption capacities (qm) of the thesis materials (2,4Al1N: qm = 35,71 mg/g, 0,3FeN: qm = 18,98 mg/g) are higher than those of published materials Adsorption kinetics study show that the pseudo-second-order model fitted the experimental data quite well The activation energy of As(V) adsorption onto Fe-bentonite, Fe-CTAB-bentonite, Al-bentonite and Al-CTAB-bentonite materials are calculated 80,29 kJ/mol, 42,03 kJ/mol, 41,90 kJ/mol and 0,4CN2Al, respectively The thermodynamic 55 parameters for As (V) adsorption onto four selected materials were determined indicating that this adsorption was spontaneous Among the investigated materials, CTAB-bentonite materials show the highest phenol red adsorption efficiency, the following were Al-CTAB-bentonite and Fe-CTAB-bentonite materials The factors influenting the adsorption of phenol red onto organic bentonite and organic-inorganic hybrid bentonite materials from aqueous solution such as pH, inital concentration of phenol red, temperature were investigated The kinetic data are well described by a pseudo-secondorder kinetic model for the phenol red adsorption onto investigated materials The adsorption isotherms are found to be of Langmuir type The phenol red monolayer adsorption capacities (qm) decrease in the following order: CTAB-bentonite (166,7 mg/g), Al-CTAB-bentonit e (125,0 mg/g) and Fe-CTAB-bentonite (100 mg/g) The thermodynamic parameters such as Go, Ho, So indicate that phenol red adsorption process is spontaneous (Go < 0), endothermic (Ho > 0) and increases entropy (So > 0) From the results of recherche, the fact has been established that organic bentonite and organic-inorganic hybrid bentonite can be used effectively as adsorbents for the removal of large size organic pollutants ( > 15 ) Fe-bentonite material shows both high conversation and high selectivity for the alkylation of aromatics The rate of p-xylene benzylation is enhanced by increasing molar ratio of the reactants, catalyst mass and reaction temperature The activation energy for the p-xylene benzylation over Fe-bentonite was determined 120,76 kJ/mol The precious point of thesis is the fact that kinetics of p-xylene benzylation was be modelled considering LangmuirHinshelwood mechanism This opens prospect of using pillared bentonite as catalyst for the Friedel-Crafts alkylation The recherche results of structure, material surface properties, adsorption thermodynamics, adsorption kinetics and p-xylene benzylation showed that adsoptive and catalytic processes take place at outer surfaces and in mesopores of material particles The intercalation of agents like Fe3+, Al3+, CTAB into interlayer space of nontronite plays a role to change the nature of adsoptive and catalytic sites, which stay in and show up in capillary walls and outer surfaces of material particles creating sites that are easy to approach to the agents (molecules, ions, ) participating in adsoptive and catalytic processes 56 [...]... Purification of Co Dinh bentonite - Synthesis of CTAB-bentonite - Synthesis of Fe-bentonite and Fe-CTAB-bentonite - Synthesis of Al-bentonite and Al-CTAB-bentonite - Recherche of As(V) adsorption on Fe-bentonite, Fe-CTABbentonite, Al-bentonite, Al-CTAB-bentonite materials from aqueous solution - Recherche of phenol red adsorption on CTAB-bentonite, FeCTAB-bentonite, Al-CTAB-bentonite materials from... (16,56 m2/g) u nh hn rt nhiu so vi bentonit ban u 120 3 -1 L- ợ ng hấp phụ (cm g ,SPT) 150 90 60 30 0 0,0 0,2 0,4 0,6 0,8 1,0 o á p suất t- ơng đối (P/P ) Hỡnh 3.27 ng hp ph - kh hp ph N2 ca cỏc mu N, 0,4C1N, 0,3FeCN v 1,5FeCN 14 3.4 TNG HP VT LIU Al -BENTONIT V Al-CTAB -BENTONIT 3.4.1 Tng hp vt liu Al -bentonit Qua kho sỏt cỏc yu t nh hng n cu trỳc vt liu Albentonit nh nng bentonit, t l mol nOH /nAl 3 v... vt liu bentonit hu c (CTAB -bentonit) , bentonit vụ c (Fe -bentonit, Al -bentonit) v bentonit lai hp hu c vụ c (Fe-CTAB -bentonit, Al-CTAB -bentonit) bng phng phỏp trao i ion Cỏc kt qu c trng vt liu cho thy, tựy iu kin tng hp, cỏc cation oligome Fe, Al((Fe3+)x, (Al3+)y, Fe13m+, Al13n+, vi x, y, m, n l cỏc h s) ó chốn vo NONT lm tng khong cỏch khụng gian d001.Vt liu bentonit vụ c thu c cú cu trỳc mao qun... Fe -bentonit, Fe-CTAB -bentonit, Al -bentonit v Al-CTAB -bentonit tớnh c ln lt l 80,29 kJ/mol, 42,03 kJ/mol, 41,90 kJ/mol, 42,27 kJ/mol Cỏc thụng s nhit ng 26 ca quỏ trỡnh hp ph As(V) trờn bn vt liu kho sỏt cng ó c xỏc nh, chng t rng quỏ trỡnh hp ph As(V) trờn cỏc vt liu ny l t din bin 4 Trong cỏc vt liu kho sỏt, CTAB- bentonit cú hiu sut hp ph phenol ln nht, sau ú l Al-CTAB -bentonit v Fe-CTABbentonit Cỏc yu... interlayered clay 1.10 Arsenic adsorption on bentonite and modified bentonite 1.11 Phenol red adsorption on bentonite and bentonite modified 1.6 Friedel-Crafts benzylation of divers aromatics using different catalysts Chapter 2 OBJECTIVES, CONTENTS AND EXPERIMENTAL METHODS 2.1 OBJECTIVES - Synthesis of organic bentonite, inorganic bentonite and organicinorganic hybrid bentonite materials - Application of these... phenol adsorptions, or catalysts for p-xylene benzylation 2.2 CONTENTS - Purification of Co Dinh bentonite and recherche of its composition, structure and property - Synthesis of CTAB-bentonite, Fe-bentonite, Fe-CTABbentonite, Al-bentonite and Al-CTAB-bentonite - Recherche of the As(V) adsorption on the modified bentonite materials from aqueous solution: choice of adsorbents, effect of pH 35 and mechanism... 0,028 0,8CN2Al 10,07 0,11 Vt liu Al-CTAB -bentonit tng hp cú cu trỳc mao qun á p suất t- ơng đối (P/P ) nhng b mt riờng rt thp so Hỡnh 3.43 ng ng nhit hp vi bentonit ban u ph v kh hp ph N2 (a) ca 20 10 0 0,0 0,2 0,4 0,6 0,8 1,0 o 0,4CN2Al v 0,8CN2Al 3.5 NGHIấN CU S HP PH As(V) TRONG DUNG DCH 16 NC TRấN VT LIU Fe -BENTONIT, Fe-CTAB -BENTONIT, Al -BENTONIT, Al-CTAB -BENTONIT 3.5.1 La chn cht hp ph v xỏc nh... cu ny nhn thy bentonit hu c v bentonit hu c - vụ c cú trin vng trong hp ph cỏc hp cht hu c ụ nhim cú kớch thc ln ( > 15 ) 5 Vt liu Fe -bentonit l cht xỳc tỏc tt cho phn ng alkyl húa cỏc hp cht thm vi chn lc v chuyn húa cao.Tc phn ng benzyl húa p-xylen trờn xỳc tỏc Fe -bentonit tng theo t l mol cỏc cht tham gia phn ng, hm lng xỳc tỏc v nhit Nng lng hot húa ca phn ng ny trờn xỳc tỏc Fe -bentonit xỏc... like bentonite and functionalized bentonite Therefore, the use of modified bentonite material in Vietnam will bring high economic benefits According to all of these reasons, the present work is focused in the ô Studies on Co Dinh bentonite functionalization and application in catalyse-adsorption ằ 2 Specific aims and main tasks of the thesis Our aim is to synthesize organic bentonite, inorganic bentonite,... Vt liu Fe -bentonit v Fe-CTABbentonit cú kh nng hp ph tt As(V) trong nc pH 3,0, cũn Al -bentonit v Al-CTAB -bentonit pH 4,0 Dung lng hp ph As(V) trờn cỏc vt liu ca lun ỏn (2,4Al1N vi qm = 35,71 mg/g, 0,3FeN vi qm = 18,98 mg/g) cao hn cỏc vt liu khỏc ó cụng b ng hc hp ph As(V) trờn cỏc vt liu kho sỏt phự hp khỏ tt vi mụ hỡnh ng hc biu kin bc 2 Nng lng hot húa ca quỏ trỡnh hp ph As(V) trờn Fe -bentonit,