32 8 2013 8 ENVIRONMENTAL CHEMISTRY Vol 32 No 8 August 2013 DOI 10 7524 /j issn 0254-6108 2013 08 019 * 张 1 佳 2 任秉雄 王 3 鹏 1,3** 王崇臣 1 100044 2 100037 3 100044 298 303 308 313 318K Langmuir Freundlich Dubinin-Radushkevish Gibbs "G θ "H θ "S θ Langmuir Gibbs "G θ "H θ "S θ 1 1t 744 t 10% 20% 50% 2 1 mg L - 1 1 1 3 1 3 4 1 5-7 2000 t 1 1 1 722S SHZ-82 Spectrum-100 - C 16 H 18 N 3 SCl 3H 2 O 373 90 2012 11 15 * PHR201106124 2010ZX07320-002 2013 ** Tel 010-68322124 E-mail chongchenwang@ 126 com
1540 32 30 < 0 59 mm 1 2 Spectrum 100 4000 400cm - 1 KBr 1 3 250 ml 6 8 10 g L - 1 200 ml 60 80 100 mg L - 1 0 1 mol L - 1 NaOH HCl ph 308 K 150 r min - 1 0 45 μm 662 nm A 1 2 8 q = C 0 - C e V W 1 η = C 0 - C e 100% 2 C 0 q mg g - 1 C 0 mg L - 1 C e mg L - 1 V L W g 1 4 ph ph 8 g L - 1 80 mg L - 1 ph 5 5 ph 3 5 4 5 5 5 6 5 7 5 0 45 μm 3 0 ml A ph 1 5 8 g L - 1 80 mg L - 1 308 K 0 45 μm 3 0 ml A Langergren 3 9 4 9 1 6 ln( q e - q ) t = lnq e - k 1 t 3 t = 1 + 1 t 4 q t k 2 q 2 q e e 250 ml 40 80 120 160 200 mg L - 1 8 g L - 1 298 303 308 313 318 K 150 r min - 1 q e 5 298 303 308 313 318 K Langmuir Freundlich Dubinin-Radushkevish 5 7 8 C e q e = 1 q max K L + C e q max 5 lnq e = lnk F + 1 n lnc e 6 ( ) e lnq e = lnq max - K DR ε 2 ε = RTln 1 + 1 C q e mg g - 1 q max mg g - 1 K L Langmuir L mg - 1 n Freundlich L g - 1 ε polenyi K DR E 7
8 1541 E = 2K DR - 1 /2 1 7 8 9 10 ΔG θ ΔH θ ΔS θ ΔG θ = - RTlnK L 8 lnk L = ΔSθ R - ΔHθ RT R 8 314 J mol - 1 K - 1 T K K L Langmuir L mg - 1 lnk L 1 /T ΔG θ ΔH θ ΔS θ 9 2 2 1 1 3433 cm - 1 OH 17 cm - 1 3416 cm - 1 OH 1631 cm - 1 C O 2 cm - 1 1629 cm - 1 2925 cm - 1 2923 cm - 1 CH 3 1033 cm - 1 1032 cm - 1 OH 1000 cm - 1 4 Fig 1 1 Infrared spectra of tea seed powder 2 2 T = 308 K 60 80 100 mg L - 1 6 8 10 g L - 1 t q η 2 2 a q 6 g L - 1 100 mg L - 1 40 min 20 30 min 2 8 g L - 1 80 mg L - 1 6 min 95% 15 min 98% 30 min 99% 2 b 2 3 ph 308 K 8 mg L - 1 80 mg L - 1 ph 3 5 4 5 5 5 6 5 7 5 3 9 50 mg g - 1 9 72 mg g - 1 20 30 min ph 7 5
1542 32 97% ph 3 5 4 5 5 5 6 5 95% ph 5 5 9 62 mg g - 1 96% 2 a b Fig 2 Adsorption amount a and removal rate b of methylene blue on tea seed powder as a function of time with different initial methylene blue concentration and tea seed powder dose Fig 3 3 ph Effect of ph value on the adsorption amount and removal rate of methylene blue on tea seed powder 2 4 Langergren 3 4 4 Fig 4 4 a b Kinetics equation fitting curve a Pseudo-first order kinetics b Pseudo-second order kinetics
8 1543 4 a b R 2 = 0 9999 k 2 = 1 009 g mg - 1 min - 1 q e 9 940 mg g - 1 q e 9 873 mg g - 1 11 5 q t t 1 /2 15 min t 1 /2 = 3 9 min 1 /2 t 1 /2 75 min t 1 /2 = 8 7 min 1 /2 60 mg L - 1 100 mg L - 1 k 0 334 1 534 mg g - 1 min - 1 /2 6 5 6 Fig 5 Intra-particle diffusion plots for methylene blue adsorption on tea seed powder Fig 6 Pore diffusion plots for methylene blue adsorption on tea seed powder 2 5 5 Langmuir Freundlich Dubinin-Radushkevish 5 7 Langmuir 2 1 7 1 Langmuir > Dubinin-Radushkevich > Freundlich Langmuir R 2 > 0 9 K L q max / K 1 q max / mg g - 1 Table 1 Langmuir Freundlich Dubinin-Radushkevish Constants of Langmuir Freundlich and Dubinin-Radushkevish isotherms for methylene q max / mg g - 1 blue adsorption by tea seed powder at different temperatures Langmuir K L / L mg - 1 R 2 Freundlich K F / L g - 1 1 /n R 2 D-R K DR E / kj mol - 1 R 2 298 9 05 9 19 0 266 0 9824 6 877 0 117 0 6949 0 034 3 824 0 8565 303 7 15 7 31 0 159 0 9678 6 370 0 095 0 3961 0 091 2 343 0 7331 308 6 02 6 19 0 128 0 9585 6 370 0 068 0 1648 0 149 1 835 0 5471 313 4 65 4 84 0 094 0 9346 6 645 0 027 0 0222 0 108 2 150 0 2974 318 3 57 3 75 0 077 0 9055 7 159 0 014 0 0038 0 102 2 210 0 1459
1544 32 2 6 8 9 ΔG θ ΔH θ ΔS θ lnk L K L Langmuir 1 /T 8 ΔH θ ΔS θ ΔG θ ΔH θ ΔS θ 2 Fig 7 7 8 Langmuir Langmuir isotherms for the adsorption of methylene Fig 8 Effect of temperature on the equilibrium constants blue by tea seed powder of methylene adsorption blue by tea seed powder 2 ΔG θ ΔH θ ΔS θ 0 ΔG θ 0-20 kj mol - 1 ΔG θ - 80-400 kj mol - 1 ΔG θ - 27 81-29 14 kj mol - 1 12 ΔH θ < 0 ΔH θ 30 kj mol - 1 13 ΔS θ < 0 Table 2 2 Values of thermodynamic parameters for the adsorption of methylene blue on tea seed powder /K K L / L mg - 1 ΔG θ / kj mol - 1 ΔS θ / J mol - 1 K - 1 ΔH θ / kj mol - 1 298 127973-29 14 303 76228-28 32 308 61322-28 23-62 33-47 47 313 45024-27 88 318 37072-27 81 3 1 298 K 8 g L - 1 80 mg L - 1 30 min 99% 2 0 999 3 3 Langmuir ph 3 5 7 5 9 50 mg g - 1 9 72 mg g - 1 ph ph 4 ΔG θ ΔH θ ΔS θ 0
8 1545 1 Grégorio C Non-conventional low-cost adsorbents for dye removal A review J Bioresource Technology 2006 97 9 1061-1085 2 Keggin Dawson J 2009 7 1042-1045 3 Mittal A Malviya A Kaur D et al Studies on the adsorption kinetics and isotherms for the removal and recovery of Methyl Orange from wastewaters using waste materials J Journal of Hazardous Materials 2007 148 1 /2 229-240 4 Gadd G M Biosorption Critical review of scientific rationale environmental importance and significance for pollution treatment J Journal of Chemical Technology & Biotechnology 2009 84 1 13-28 5 Forgacs E Cserháti T Oros G Removal of synthetic dyes from wastewaters A review J Environment International 2004 30 7 953-971 6 Senthilkumaar S Kalaamani P Porkodi K et al Adsorption of dissolved Reactive red dye from aqueous phase onto activated carbon prepared from agricultural waste J Bioresource Technology 2006 97 14 1618-1625 7 Wang S Zhu Z H Characterisation and environmental application of an Australian natural zeolite for basic dye removal from aqueous solution J Journal of Hazardous Materials 2006 136 3 946-952 8 B J 2011 31 12 2601-2608 9 J 2009 29 12 2510-2518 10 J 2009 32 11 19-23 11 J 2011 5 10 2288-2292 12 3 4 J 2009 28 3 361-363 13 - J 2005 31 132 15-19 14 Qin Qingdong Ma Jun Liu Ke Adsorption of anionic dyes onammonium-functionalized MCM-41 J Journal of Hazardous Materials 2009 162 133-139 15 Haquea E Leea J E Jangb I T et al Adsorptive removal of methyl orange from aqueous solution with metal-organic frameworks porous chromium-benzenedicarboxylates J Journal of Hazardous Materials 2010 181 535-542 16 J 2011 34 12 45-49 17 B J 2008 28 11 1009-1013 18 J 2012 31 5 646-652 19 J 2012 31 5 669-676 Mechanistic study on adsorption of methylene blue on tea seed powder ZHANG Jia 1 REN Bingxiong 2 WANG Peng 3 WANG Chongchen 1 3* 1 Beijing Climate Change Response Research and Education Center Beijing University of Civil Engineering and Architecture Beijing 100044 China 2 Beijing Cycletimes Environment Science & Technology Co Ltd Beijing 100037 China 3 Key Laboratory of Urban Storm Water System and Water Environment Beijing University of Civil Engineering and Architecture Beijing 100044 China ABSTRACT In order to investigate the dye adsorption properties of tea seed powder methylene blue was chose as the sorbate The data obtained at different temperatures 298 303 308 313 318 K were fitted with Langmuir Freundlich and Dubinin-Radushkevish models to describe the equilibrium isotherms The kinetics rates were modeled using pseudo-first-order and pseudo-second-order kinetic equations The Gibbs free energy "G θ enthalpy change "H θ and entropy change "S θ were calculated The results revealed that the equilibrium adsorption amount decreased with the increase of temperature The adsorption could be well depicted by the Langmuir adsorption isotherm The Gibbs free energy "G θ enthalpy change "H θ and entropy change "S θ were negative indicating that the adsorption was a spontaneous exothermic and decreasing entropy process The adsorption kinetics followed pseudo-second-order kinetic equation Keywords tea seed powder methylene blue adsorption thermodynamics kinetics