Abstract
The kinetics of decolorization of methylene blue (MB+) with sodium sulphite in aqueous media was investigated over the temperature range 20-40°C. The kinetic studies were carried out as a function of different variables like concentration, pH, and temperature on rate of decolorization. The rate of the reaction was found to be [H+] dependent and first order in both [MB+] and reductant. The empirical rate law conforms to the equation: Where K1 is the protonation constant, and k2 and k3 are overall pseudo-second order rate constants for the decolorization of MB+ with 2 3 SO − . The rate was found to increase linearly with temperature. The rate of decolorization decreased after addition of Co(II), Ni(II), Mn(II) and Zn(II), but increased after addition of Fe(II) and Cu(II). The activation parameters (Ea, ΔG#, ΔH# and ΔS#) of the decolorization reaction of MB+ with 2 3 SO − in absence and in presence of Fe(II) and Cu(II) were calculated.
Highlights
A variety of hazardous pollutants are discharged into the aquatic bodies from several industrial streams [1,2]
Methylene blue is blue when it is in an oxidizing environment, but colorless (leuco methylene blue (LMB)) if it is exposed to a reducing agent (Scheme 1)
It is seen that the decolorization of MB+ is relatively fast at the beginning and decreases as the reaction progresses
Summary
A variety of hazardous pollutants are discharged into the aquatic bodies from several industrial streams [1,2]. The use of methylene blue as a dye in textile industry [5] has decreased slightly in last few years due to its high light sensitivity It is still widely used for the manufacture of color pens and polygraphic inks [6]. To find a general process for treatment of the color of dye used in dyeing processes is very difficult due to the complexity and variety of these types of industrial wastewater The disadvantages of these methods are sludge formation, waste disposal and high operation cost, time consuming and ineffectiveness in cases where complicated aromatic compounds are present [20,21]. Methylene blue is blue when it is in an oxidizing environment, but colorless (leuco methylene blue (LMB)) if it is exposed to a reducing agent (Scheme 1) These processes have found applications in numerous inventions like data recording holographic industries, optical data storage, food and pharmaceutical industries. J Phys Chem Biophys 4: 136. doi:10.4172/2161-0398.1000136
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
