Spectrokinetics study of probable effects of diverse inorganic ions on bleaching of dye

Abstract

Toluidine blue (TB) is an important anticoagulant metachromasia molecule showing a pronounced variation in the visible spectrum due to the aggregation phenomenon and electrostatic interaction with the charged synthetic and biologic polymers. The current study describes the interactive role of diverse inorganic material ions on the bleaching of toluidine blue (tolonium chloride) (TB⁺) with urea in acidic and basic media using the spectrophotometric technique. The spectra of TB and urea with different cations and anions were monitored and their characteristic features are presented here. The negative effect of added cations on reduction may be the result of altered electron pathways which led to suppression of the reduction/bleaching of TB, while a slight decrease in dye reduction by added anions may be due to the scavenging of the OH* radical. It has been observed in the case of Co²⁺ that in addition to the electron-transfer reaction, other processes like layer and precipitate formation also appear to be taking place. The dye bleaching process followed pseudo first order kinetics with respect to TB, urea, and H⁺ ion, whereas significant decoloration in the presence of urea proved that reductants control the redox reaction. No decoloration in acidic medium with diverse ions was seen compared to alkaline media, showing that water pH played an important role in the bleaching of dye. The reduction/bleaching of dye was investigated at different temperatures, and energy parameters were evaluated for a TB⁺-Urea reaction, including the energy of activation (E_a = 39.60 kJ·mol^-1), enthalpy of activation (∆H^# = 34kJ·mol^-1), entropy of activation (∆S^# = 146.5 kJ mol^-1·K^-1), and free energy of activation (ΔG* = -52.35 kJ·mol^-1). A mechanism of interaction of diverse ions in dye bleaching and a mechanism of reduction based on the above findings is proposed.

Keywords

TB / diverse ions / suppress / decoloration

References

[1] Pakshirajan K, Rene E R, Swaminathan T. Decolourisation of azo dye containing synthetic wastewater in a rotating biological contactor reactor: a factorial design study. International Journal of Environment and Pollution, 2009, 37(2-3): 266-275

[2] Cooper A T, Goswami D Y. Evaluation of methylene blue and rose bengal for dye sensitized solar water treatment. Journal of Solar Energy Engineering, 2002, 124(3): 305-310

[3] Kornaros M, Lyberatos G. Biological treatment of wastewaters from a dye manufacturing company using a trickling filter. Journal of Hazardous Materials, 2006, 136(1): 95-102

[4] Mills G, Hoffmann M R. Photocatalytic degradation of pentachlorophenol on titanium dioxide particles: identification of intermediates and mechanism of reaction. Environmental Science & Technology, 1993, 27(8): 1681-1689

[5] Dhale A D, Mahajani V V. Reactive dye house wastewater treatment. Use of hybrid technology: membrane, sonication followed by wet oxidation. Industrial & Engineering Chemistry Research, 1999, 38(5): 2058-2064

[6] Yeung K W, Shang S M. The influence of metal ions on the aggregation and hydrophobicity of dyes in solutions. Coloration Technology, 1999, 115(7-8): 228-232

[7] Rauf M A, Ashraf S S, Alhadrami S N. Photolytic oxidation of coomassie brilliant blue with H₂O₂. Dyes and Pigments, 2005, 66(3): 197-200

[8] Ashraf S S, Rauf M A, Alhadrami S. Degradation of methyl red using Fenton’s reagent and the effect of various salts. Dyes and Pigments, 2006, 69(1-2): 74-78

[9] Rauf M A, Bukallah S B, Hamidi A, Sulaiman A, Hamadi F. The effect of operational parameters on the photo-induced decoloration of dyes using a hybrid catalyst V₂O₅/TiO₂. Chemical Engineering Journal, 2007, 129(1-3): 167-172

[10] Chen C, Li X, Ma W, Zhao J, Hidaka H, Serpone N. Effect of transition metal ions on the TiO₂-assisted photodegradation of dyes under visible irradiation: a probe for the interfacial electron transfer process and reaction mechanism. J Phys Chem B, 2002, 106(2): 318-324

[11] Missmann M, Jank S, Laimer K, Gassner R. A reason for the use of toluidine blue staining in the presurgical management of patients with oral squamous cell carcinomas. Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology, 2006, 102(6): 741-743

[12] Jonnalagadda S B, Dumba M. Reduction of toluidine blue by stannous ion at low pH: Kinetics and simulation. International Journal of Chemical Kinetics, 1993, 25(9): 745-753

[13] Jonnalagadda S B, Tshabalala D. A kinetic study of the reduction of toluidine blue with thiourea in acidic solution. International Journal of Chemical Kinetics, 1992, 24(11): 999-1007

[14] Azmat R, Yasmeen B, Uddin F. Kinetics of methylene blue reduction with oxalic acid by visible spectrophotometric method. Asian Journal of Chemistry, 2007, 19: 1115-1121

[15] Azmat R, Ahmed S, Qureshi S, Mohammed F V, Uddin F. Aerobic oxidation of D-glucose by methylene green in alkaline aqueous solution by visible spectrophotometry. Journal of Applied Science, 2006, 6(13): 2784-2788

[16] Azmat R, Uddin F. Photo bleaching of methylene blue with galactose and D-mannose by high intensity radiations. Canadian Journal of Pure and Applied Sciences, 2008, 2: 275-283

[17] Azmat R, Qamer N, Saeed A, Uddin F. Reduction of methylene green by EDTA. Kinetic and thermodynamic aspects. Chinese Journal of Chemistry, 2008, 26: 631-634

[18] Uddin F, Hasnain Q Z. Photochemical reduction of thionine with dimethylamine. Kuwait J Sci Eng, 2002, 29: 67-85

[19] Uddin F. Kinetics of photochemical reactions of thionine with thiourea. European Journal of Organic Chemistry, 2000, 7: 1345-1351

[20] Arikan B, Tuncay M. Micellar effects and reactant incorporation in reduction of toluidine blue by ascorbic acid. Dyes and Pigments, 2005, 64(1): 1-8

[21] Mahadevan J, Guha S N, Kishore K, Moorthy P N. One-electron reduction of toluidine blue. A pulse radiolysis study. Journal of Chemical Sciences, 1989, 101: 43-53

[22] Snehalatha T, Rajanna K C, Saiprakash P K. Methylene blue-ascorbic acid: an undergraduate experiment in kinetics. Journal of Chemical Education, 1997, 74(2): 228-233

[23] Karunaratne DeFazio S A, Lemley A T. Electrochemical treatment of acid dye systems: sodium meta-bisulfite addition to the andco system. Journal of Environmental Science and Health, Part A, Toxic/Hazardous Substances and Environmental Engineering, 1999, 34(2): 217-240

[24] Muruganandham M, Swaminathan M. Photocatalytic decolorisation and degradation of reactive orange 4 by TiO₂-UV process. Dyes and Pigments, 2006, 68(2-3): 133-142

RIGHTS & PERMISSIONS

2014 Higher Education Press and Springer-Verlag Berlin Heidelberg