Enhancement of phenol recovery from wastewater by nanofluid utilizing liquid-liquid extraction method in a membrane-based contactor

This study aims to investigate the effect of adding nanoparticles (NPs) to phenol solvent on the recovery of phenol from wastewater by applying the liquid-liquid extraction technique in a contactor of a hollow fiber membrane. The resulting solution, called na-nofluid, is composed of dispersed SiO2 nanoparticles in a 10% (v/v) tributyl phosphate (TBP) /kerosene mixture. The solvent loaded with phenol was regenerated using NaOH solution in a stripping hollow fiber membrane contactor. The stability of SiO2 NPs in the nanofluid was also investigated. Furthermore, the influence of operating conditions, such as NPs concentration, organic phase flow rate (Qorg), aqueous phase flow rate (Qaqu), and inlet phenol concentration on extraction efficiency (& eta;extrac), extraction flux (Jextrac), and stripping efficiency (& eta;stripp) were evaluated. The results showed that after 24 h, approxi-mately 80% of the initial dispersion of SiO2 NPs into the nanofluid was achieved. Furthermore, it was observed that adding NPs to the TBP/kerosene solution improved & eta;extrac, Jextrac, and & eta;stripp. Among the studied NPs concentrations, 0.02 wt% exhibited higher values of & eta;extrac, Jextrac, and & eta;stripp. Additionally, it was found that increasing Qorg led to a significant increase in & eta;extrac and Jextrac, but a decrease in & eta;stripp. Conversely, increasing Qaqu led to a decrease in both & eta;extrac and & eta;stripp, but an increase in Jextrac. At an inlet phenol concentration of 1000 ppm and with Qorg and Qaqu at the same value of 150 mL min-1, the use of a solvent containing 0.02 wt% SiO2 NPs resulted in & eta;extrac of 97.8% and & eta;stripp of 97.7%. & COPY; 2023 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.