Phenol recovery from phenolic resin manufacturing: Viability of the emulsion pertraction technology

In this paper, the viability of emulsion pertraction technology (EPT) for phenol recovery from the aqueous condensates obtained in the manufacturing of phenolic resins is described. This waste is highly concentrated in phenol (15–25 wt%) and formaldehyde (10–15 wt%). The experimental work was performed using real effluents of a phenolic resin producer. The simultaneous selective extraction and recovery of phenol from the condensate is performed in a single hollow fiber membrane contactor. Kerosene and its mixtures with a highly effective phenol extractant, Cyanex 923, were used as organic solvents. Phenol was transferred to the caustic stripping phase to give a final phenol concentration in the treated waste less than 0.5 wt%, whereas formaldehyde remained in the feed, thus providing the required selectivity. Phenol recovery was attained after acidification of the concentrated stripping phase.

The viability of emulsion pertraction technology (EPT) for the phenol recovery from waste aqueous condensates generated in the manufacturing of phenolic resins is performed. By using a hollow fiber membrane contactor, kerosene and its mixture with Cyanex 923 as organic extractant, and sodium hydroxide as stripping phase, the phenol concentration in the feed is reduced from the initial 25 wt% to values lower than 0.5 wt%. By including Cyanex 923 in the composition of the extractant phase, the kinetic of phenol separation is increased over the use of single kerosene. Acidification is proposed for phenol recovery from the stripping phase, providing an organic phase with a phenol concentration of 70 wt%, adequate for its re-use in the manufacturing of phenolic resins.