Clean Technology, Vol.18, No.1, 76-82, March, 2012
제올라이트를 이용한 말라카이트 그린의 흡착평형, 동력학 및 열역학 연구
Adsorption Equilibrium, Kinetics and Thermodynamics Studies of Malachite Green Using Zeolite
E-mail:
초록
폐수로 부터 유독한 말라카이트 그린 성분을 제거하는데 있어서 제올라이트의 활용가능성을 살펴보았다. 흡착실험은 298, 308 및 318 K에서 수행하였으며, 흡착에 대한 온도, 접촉시간과 초기농도의 영향을 조사하였다. 흡착자료를 기초로 Langmuir와 Freundlich 흡착등온식에 대한 적합성을 평가하였다. 흡착공정은 Freundlich 흡착등온식이 잘 맞았으므로 제올라이트 표면의 불균일한 에너지에 의해 선택적인 흡착이 이루어짐을 알았다. 계산된 흡착등온선의 상수 값으로부터 제올라이트에 의해서 말라카이트 그린의 효과적인 처리가 가능하다는 것을 알 수 있었다. 동력학적 실험으로부터, 흡착공정은 유사이차반
응속도식에 잘 맞으며, 속도상수(k2) 값은 말라카이트 그린의 초기농도가 증가할수록 감소하였다. 활성화에너지, 엔탈피,엔트로피 및 자유에너지변화와 같은 열역학 파라미터들은 흡착공정의 특성을 평가하기 위하여 조사하였다. 활성화에너지의 계산값은 제올라이트에 대한 말라카이트 그린의 흡착이 물리적 공정임을 나타냈다. 자유에너지변화값(ΔG° = -6.47~-9.07 kJ/mol)과 엔탈피변화값(ΔH° = +32.414 kJ/mol)은 흡착공정이 298~318 K 범위에서 자발적이고 흡열과정이라는 것을 나타냈다.
The paper includes utlization of zeolite as potential adsorbent to remove a hazardous malachite green from waste water. The adsorption studies were carried out at 298, 308 and 318 K and effects of temperature, contact time, initial concentration on the adsorption were measured. On the basis of adsorption data Langmuir and Freundlich adsorption isotherm model were also
confirmed. The equilibrium process was described well by Freundlich isotherm model, showing a selective adsorption by irregular energy of zeolite surface. From determined isotherm constants, zeolite could be employed as effective treatment for removal of malachite green. From kinetic experiments, the adsorption process followed the pseudo second order model, and the
adsorption rate constant (k2) decreased with increasing initial concentration of malachite green. Thermodynamic parameters like activation energy, change of free energy, enthalpy, and entropy were also calculated to predict the nature adsorption. The activation energy calculated from Arrhenius equation indicated that the adsorption of malachite green on the zeolite was physical
process. The negative free energy change (ΔG° =-6.47~-9.07 kJ/mol) and the positive enthalpy change (ΔH° = +32.414 kJ/mol) indicated the spontaneous and endothermic nature of the adsorption in the temperature range 298~318 K.
- Zhou L, Gao C, Xu W, ACS Appl. Mater. Interfaces., 2, 1483 (2010)
- Blackburn R, Environ.Sci. Technol., 38, 4905 (2004)
- Shi BY, Li GH, Wang DS, Feng CH, Tang HX, J. Hazard. Mater., 143(1-2), 567 (2007)
- Lee J, Choi S, Thiruvenkatacharib R, Chim W, Moon H, Water Res., 40, 435 (2006)
- Mahanta D, Madras G, Radhakrishnan S, Patil S, J. Phys. Chem. B, 113(8), 2293 (2009)
- Mahanta D, Madras G, Radhakrishnan S, Patil S, J. Phys. Chem. B, 112(33), 10153 (2008)
- Chen W, Lu W, Yao Y, Xu M, Environ. Sci. Technol., 41, 6240 (2007)
- Wong YC, Szeto YS, Cheung WH, McKay G, Langmuir, 19(19), 7888 (2003)
- Fernandez J, Kiwi J, Lizama C, Freer J, Baeza J, Mansilia H, J. Photochem. Photobiol. A., 151, 213 (2002)
- Tan IAW, Ahmad AL, Hameed BH, J. Hazard. Mater., 154(1-3), 337 (2008)
- Samiey B, Toosi A, Central Eur. J. Chem., 8, 906 (2010)
- Gupta VK, Mittal A, Krishnan L, Gajbe V, Sep. Purif. Technol., 40(1), 87 (2004)
- Mittal A, J. Hazard. Mater., 133(1-3), 196 (2006)
- Zhang J, Li Y, Zhang C, Jing Y, J. Hazard. Mater., 150, 774 (2008)
- Kumar K, Sivanesan S, Ramamurthi V, Proc. Biochem., 40, 2865 (2005)
- Ahmad R, Kumar R, J. Environ. Manag., 91, 1032 (2010)
- Chowdhury S, Mishra R, Saha P, Kushwaha P, Desalination, 265(1-3), 159 (2011)
- Sekhar C, Kalidhasan S, Rajesh V, Rajesh N, Chemosphere., 77, 842 (2009)
- Baek MH, Ijagbemi CO, Se-Jin O, Kim DS, J. Hazard. Mater., 176(1-3), 820 (2010)
- Bekci Z, Ozveri C, Seki Y, Yurdakoc K, J. Hazard. Mater., 154(1-3), 254 (2008)
- Nollet H, Roels M, Lutgen P, Van der Meeren P, Verstraete W, Chemosphere., 53(6), 655 (2003)
- Ijagbemi CO, Baek MH, Kim DS, J. Hazard. Mater., 166(1), 538 (2009)
- Jaycock MJ, Parfitt GD, “Chemistry of Interfaces,” Ellis Horwood Ltd., Chichester (1981)
- Dogan M, Alkan M, Demirbas O, Ozdemir Y, Ozmetin C, Chem. Eng. J., 124(1-3), 89 (2006)
- Lee JJ, Clean Technol., 17(2), 97 (2011)