Adsorption and Reaction of Model Pollutants

Methylene blue (MeB) is a pollutant present in water stream effluents from dye factories. 

Experiments performed using MeB have intrinsic advantages as MeB blue s colour disappears as photoconversion progresses and provides a quick assessment of the reactor performance. This colour change is easy to follow via spectrophotometery (k = 664 nm). 

Runs were developed in the Photo-CREC-Water I (Chapter II) with a water recirculation of 1720 mL min . Initial MeB concentrations were varied in the 5-50-/rmole range during the experiments. Samples were analyzed at 664 nm using a PU8625 UVA IS spectrophotometer and Shimadzu 5050 TOC model. This allows to follow the disappearance of the model compound, the intermediate species and the total organic carbon. 

FIGURE 7.1. Change of MeB liquid phase concentration with time. Initial concentrations ( ) 27 10 mole L L (a) Period with light off (b) Period with light on . Water recirculation 1.72 L min f 

FIGURE 7.2. Eqiiilibiiiim isotherm for methylene blue and TiOa-mesh at 20 C. Water recirculation 1.72 L min . (Reprinted with permission from Ind. Eng. Chem. Res, 36(11), B. Senano and H.I. de Lasa, Photocatalytic degradation of water organic pollutants Kinetic modeling and energy efficiency, 4705 711. Copyright 1997 American Chemical Society). 

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