Effects of experimental conditions and kinetics of photodegradation of methylene blue over TiO₂

Abstract

The authors investigated the catalytic activity of TiO₂ for methylene blue(MB) degradation under solar light. The reaction parameters such as reaction time, TiO₂ content, temperature, pH, MB concentration and light irradiation were in attention. Then, the experimental data was analyzed to investigate the adsorption order and adsorption model. The results indicate that the optimum conditions for the removal of MB are a TiO₂ content of 0.5 g/L, 0.50 mg/L MB solution, a temperature of 30 °C and reaction time of 60 min. It was found that the amount of MB removal was decreased when the pH and temperature increased. This suggests that the removal process is exothermic. However, the solar light irradiation plays a vital role in enhancing the removal amount of MB. In the dark reaction, the ability of TiO₂ to remove MB was increased when the pH increased. The kinetics studies confirm that the adsorption of MB is the Pseudo-second-order. And the adsorption model was fitted with the Freundlich isotherm.

Keywords

Methylene blue / Photodegradation / Kinetic / TiO₂

References

[1] Fujishima A, Rao T N, Tryk D A. J. Photochem. Photobiol. C: Photochem. Rev., 2000, 1: 1.

[2] Wang G, Wu F, Zhang X, Luo M, Deng N. J. Hazard. Mater., 2006, 133: 85.

[3] Zhang X, Wu F, Wang Z, Guo Y, Deng N. J. Mol. Catal. A: Chem., 2009, 301: 134.

[4] Zhang L, Li P, Gong Z, Li X. J. Hazard. Mater., 2008, 158: 478.

[5] Hu L, Flanders P M, Miller P L. Water. Res., 2007, 41: 2612.

[6] Wu R J, Chen C C, Lu C S, Hsu P Y, Chen M H. Desalination, 2010, 250: 869.

[7] Senthilkumaar S, Porkodi K, Vidyalakshmi R. J. Photochem. Photobiol. A: Chem., 2005, 170(3): 225.

[8] Sauer T, Cesconeto Neto G, Jose H J, Moreira R F P M. J. Photochem. Photobiol. A, 2002, 149: 147.

[9] Chen C C, Lu C S, Chung Y C, Jan J L. J. Hazard. Mater., 2007, 141(3): 520.

[10] Xiao Q, Zhang J, Xiao C, Si Z, Tan X. Solar Ener., 2008, 82: 706.

[11] Ma M Y, Li Y J, Chen W, Li L Y. Chin. J. Catal., 2010, 31(10): 1221.

[12] Kumar V, Suh N P. Polym. Eng. Sci., 1990, 30(10): 1327.

[13] Davis R J, Gainer J L, Neal G O, Wenwu I. Water Environ. Res., 1994, 66: 50.

[14] Matthews R W. J. Chem. Soc., Faraday Trans., 1989, 85: 1291.

[15] Hsieh C T, Fan W S, Chen W Y. Microporous Mesoporous Mater., 2008, 116: 677.

[16] Chen D W, Sivakumar M, Ray A K. Develop. Chem. Eng. Miner. Process., 2000, 8(5/6): 505.

[17] Chen Y, Wang K, Lou L. J. Photochem. Photobiol. A: Chem., 2004, 163: 281.

[18] Rahchamani J, Mousavi H Z, Behzad M. Desal., 2011, 267(2/3): 256.

[19] Yao S, Li J, Shi Z. Particuol., 2010, 8: 272.

[20] Liu C C, Hsieh Y H, Lai P F, Li C H, Kao C L. Dye. Pigm., 2006, 68(2/3): 191.

[21] Toor A P, Verma A, Jotshi C K, Bajpai P K, Singh V. Dye. Pigm., 2006, 68(1): 53.

[22] Ling C M, Mohamed A R, Bhatia S. Chemos., 2004, 57(7): 547.

[23] Han C, Li Z, Shen J. J. Hazard. Mater., 2009, 168(1): 215.

[24] Gupta V K, Jain R, Nayak A, Agarwal S, Shrivastava M. Mat. Sci. Eng. C, 2011, 31(5): 1062.

[25] Lagergren S. Handlingar., 1898, 24(4): 1.

[26] McKay G, Ho Y S. Process Biochem., 1999, 34: 451.