Recovery of Aniline from Aqueous Solution Using the Membrane Aromatic Recovery System (MARS)

This paper describes a new process for the recovery of aromatic, cyclic, and aliphatic amines from aqueous streams, the membrane aromatic recovery system (MARS). The process comprises a stripping vessel, where the amines are extracted through nonporous membranes and concentrated into an HCl solution as hydrochloride salts, and a two-phase separator in which the solution from the stripping vessel is separated into an aniline-rich phase and an aqueous phase by adjusting the pH to caustic conditions with NaOH. In this study, aniline was recovered from a synthetic wastewater using silicone rubber tubing as the membrane. The stripping-solution temperature was 50 °C, and the HCl concentration was 10.45 wt %. After recovery, an organic-rich product phase containing 96.5 wt % aniline and 3.5 wt % water was obtained. The overall mass-transfer coefficients (OMTCs) for a range of amines were also investigated to demonstrate the wide potential application of MARS technology.