TITLE:
Discoloration on Methylene Blue Solutions by Direct and Catalytic Ozonation
AUTHORS:
Antonio D. Rodriguez-Lopez, Jose Garcia-Garrido, Cynthia Perez-Ramiro, Esperanza M. Garcia-Castello
KEYWORDS:
Textile Wastewater; Methylene Blue; Discoloration; Ozonation; Catalytic
JOURNAL NAME:
Journal of Materials Science and Chemical Engineering,
Vol.1 No.5,
November
7,
2013
ABSTRACT: During textile manufacturing, huge amounts of
wastewaters characterized by removed impurities and high concentrations of dye
are produced. These wastewaters cause several problems when they are discharged
to the environment. The use of ozone in wastewater treatment results of
interest. In this work we propose to assess the discoloration rate of different
synthetic wastewaters as a function of pH, dye concentration (methylene blue
(MB)) and reaction time. A comparison of discoloration rate between
conventional ozonation and catalytic ozonation salts of copper, zinc, silver
and nickel was also performed. For the optimization of the ozonation process of
colored solutions, it was used a central composite experimental design with
five replicates of the center point resulting to evaluate the influence
of the independent variables at different ranges of pH, [MB] and time. In the
catalyst-assisted ozonation, [MB], pH and the reaction time were fixed to 100
mg/L, 5.5 and 15 min, respectively. The optimized experimental conditions to
provide maximum discoloration were pH=3.3; [MB]=8.6 mg/L
and time=74.3 min. Regarding the catalyst-assisted ozonation, it was found
that CuSO4 catalyst gave better color reduction if compared with
other catalysts assayed.