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1 8,28(11) 19~113 China Environmental Science B,,,, (, 4182) (MWNTs),. (SEM),X (XRD) zeta, B.., 7.5h B 87.5%, 11.2mg/g., B,,. Langmuir, Langergren. B X 73 A (8) Removal of rhodamine B from aqueous solution by magnetic multi-wall carbon nanotubes. WANG Bin, GONG Ji-lai, YANG Chun-ping, ZENG Guang-ming, ZHOU Wen-jing (College of Environmental Science and Engineering, Hunan University, Changsha 4182, China). China Environmental Science, 8,28(11) 19~113 Abstract Multi-wall carbon nanotubes / iron oxide magnetic composite was prepared using chemical co-precipitation after multi-wall carbon nanotubes (MWNTs) were purified by nitric acid solution. The magnetic composite obtained was characterized by SEM, powder XRD and zeta SIZER. In addition, the adsorption kinetics, adsorption isotherm and effects of adsorbent dosage on magnetic composite adsorption ability were discussed in detail. The removal rate of rhodamine B reached to 87.5% at 7.5h and the maximum adsorption was 11.2mg/g. The adsorbent had good adsorption properties and could be well separated from aqueous solution by a permanent magnet. The sorption isotherm coincided with Langmuir model, the sorption processes coincided with Langergren pseudo-first-order kinetics equation. Key words multi-wall carbon nanotubes magnetic material rhodamine B adsorption capacity,, [1 3].,,, [4].,,., [5 6] [7].,,,.,,., [8 9]., B, (NH 4 ) 2 Fe(SO 4 ) 2 6H 2 O)( ), (NH 4 Fe(SO 4 ) 2 12H 2 O)( ), ( ), B( ), ( ). (MWNTs)( 1~nm), g MWNTs 25mL, 1mL,6, (5887),, yangc@hnu.cn

2 11 28 (r/min) 12h, (MWNTs).,,,1 4h,. MWNTs. Fe 2+ Fe 3+ MWNTs. Fe 2+ Fe 3+ 1:2. 5, 1.g MWNTs 1.7g (4.33mmol) (NH 4 ) 2 Fe(SO 4 ) 2 6H 2 O 2.51g (8.66mmol) NH 4 Fe(SO 4 ) 2 12H 2 O ml. 1min, 1mL 8mol/L,. ph 11~12., 5 3min 3r/min.,, 3,. 1.3 (SEM,JSM 67F), X (XRD,D 5), zeta (ZETA SIZER) ph. 1.4 B ph,. B (UV ), 554 nm mg 15mL mol/l,.5g/l, ph 4.5, (3±1),, B B mol/l mol/l, ph 4.5±.1, (3±1) 24h, B. B mol/l, ph 4.5±.1,.1g/L.9g/L, (3±1) 24h, B. 1.5 SigmaPlot ,,,. B, B,,, B.,,,. (SEM) X (XRD), zeta. SEM 1(a), 1(b). 1(a),. 1(b) ( ). 2, 2a,b [2θ( )=26.1]. 4, : Fe 3 O 4 (Mn),γ Fe 2 O 3 (Mh), α Fe 2 O 3 (H) FeO(OH). Fe 3 O 4 γ Fe 2 O 3. 2a [2θ( ) 3.2, 35.6, 43.3, 57.2] 4, Fe 3 O 4 γ Fe 2 O [1] 3, [2θ( ) 53.7, 68.2]2 α Fe 2 O [11] 3. ph zeta 3. 3,pH2~1,

3 11 B 111 zeta ph,,,. (a) zeta (mv) ph 3 zeta ph Fig.3 Effect of ph value on zeta potential (b) ,, B,7.5h 87.5%,,h,.,,24 h. 4 Langergren :ln(q e q t )=ln(q e ) kt, :q e,q t t, mg/g; k. 1 1 SEM Fig.1 SEM photograph of MWNTs and magnetic MWNTs (a) ; (b) (%) 8 6 # # MCNT Mn/Mh H MCNT/Mn/Mh a b (h) 4 B Fig.4 Kinetics graph for removal of Rhodamine B by magnetic MWNTs 6 8 2θ ( ) 2 XRD Fig.2 XRD patterns of the pure MWNTs and MWNTs / iron oxide composites a. ; b. 5 Langergren,R 2 =.972, Langergren Langmuir [12], 6. 6, Langmuir B

4 112 28,R 2 =.996, Q m 11.2mg/g, K L 34.89L/mg(Langmuir ). ln(qe-qt) (h) 5 B Langergren Fig.5 Langergren fitting for biosorption of Rhodamine B by magnetic MWNTs (mg/g) 1/ 14 a (mg/l)..35 b / 6 B Fig.6 Adsorption isotherms of Rhodamine B on magnetic MWNTs and the linear transformation of equilibrium adsorption date a. b.langmuir B ( 7). B mol/l,.1~.9g/l,, 13.7% 99.6%;.1~.5g/L ;.5g/L,.,. (%) (g/l) 7 Fig.7 The influence of adsorbent dosage B, 11.2mg/g. 3.2 Langmuir, Langergren. [1] Koch M, Yediler A, Lienert D, et al. Ozonation of hydrolyzed azo dye reactive yellow 84(CI) [J]. Chemosphere, 2,46(1): [2] Malik P K, Saha S K. Oxidation of direct dyes with hydrogen peroxide using ferrous ion as catalyst [J]. Separation and Purification Technology, 3,31(3): [3],,,. [J]., 5,25(Suppl.): [4] Wu Chung-Hsin. Adorption of reactive dye onto carbon nanotubes: Equilibrium, kinetics and thermodynamics [J]. Journal of Hazardous Materials, 7,144:93 1. [5] Lu Chungsying, Chung Yao-Lei, Chang Kuan-Foo. Adsorption of trihalomethanes from water with carbon nanotubes [J]. Water Research, 5,39:

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