Impact of pH and temperature

Keeping a sufficient requires a pH lower than 7, but it is necessary to operate at an even lower level to completely desulfurize and decrease die solubility of phenolic oils. 

The substantial reduction in COD is due to natural H2S degassing in super-saturation. Solvent extractions can be carried out at pH values between 6 and 3. 

The ratio depends on extractor design and on the initial phenol concentration in the spent caustic. To achieve the same efficiency of 75% in one stage, it may be necessary to use  

Using a four-stage system with parallel solvent currents would require a ratio of 6 to 8 to treat spent caustic with 80 g-l of phenols. However, using a countercurrent can cut this ratio to one (Fig. 52). 

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Impact of pH and Temperature on the Plasma Protein Binding Assay... 

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