Nn. Dutta et al., A NOVEL PROCESS FOR RECOVERY OF PHENOL FROM ALKALINE WASTE-WATER - LABORATORY STUDY AND PREDESIGN COST ESTIMATE, Water environment research, 70(1), 1998, pp. 4-9
A novel process for recovery of phenol from alkaline wastewater has be
en demonstrated at laboratory scale. The process is based on the polym
er-supported phase-transfer-catalyzed reaction of alkaline phenols wit
h benzoyl chloride dissolved in toluene. The reaction conducted in a t
riphase system at room temperature generates phenyl benzoate, which is
subsequently recovered as the product. Phosphonium ion immobilized on
chloromethyl polystyrene crosslinked with divinylbenzene was used as
the catalyst. Laboratory experiments were conducted in a batch slurry
reactor and a fixed-bed reactor to assess the suitability of a particu
lar reactor type to practical applications. An aqueous phase to organi
c phase volume ratio of 1:2 was found to be suitable. The slurry react
or was found to be more attractive for the reaction. Based on the resu
lt of experiments in batch slurry reactors and other processing steps,
a conceptual flow scheme was proposed for the process, and a predesig
n cost estimate was made. As such, the treatment cost of the proposed
process is higher than that of the usual solvent extraction process, b
ut the capital cost is comparable. However, the cost of the recovered
phenyl benzoate will more than offset the higher treatment cost. This
is reflected in a payback period of 1.5 years for the proposed process
as compared to 2.5 years for the typical solvent extraction process.
For industrial applications, a pilot-plant study needs to be performed
for a detailed cost analysis.