Simultaneous removal and recovery of copper(II) from acidic wastewater by hollow fiber renewal liquid membrane with LIX984N as carrier

摘要

Hollow fiber renewal liquid membrane (HFRLM), a new liquid membrane technique inspired from surface renewal theory, is used to simultaneously remove and recover copper from acidic wastewater. The commercial extractant, LIX984N, is used as a carrier in liquid membrane phase, kerosene used as a diluent. CuSO4 solutions is used to simulate acidic industrial wastewater, in which the pH is adjusted by dilute H2SO4. The mass transfer mechanisms of the process are investigated. As a carrier-facilitated transport process, the addition of LIX984N in the liquid membrane phase can greatly improve the transport performance; the organic/aqueous stripping volume ratio from 1:10 to 1:7 on lumen side mixture is better in terms of the renewal effect and diffusion resistance. The higher pH in the feed phase (>3) and H2SO4 concentration in the stripping phase around 2.0 mol L~(-1) are favorable for the transport process due to the increase of mass transfer driving forces. The mass transfer fluxes increase with increasing flow rates on two sides. The countercurrent cascade experiments show that the HFRLM process could carry out the simultaneous removal and recovery of copper from wastewater successfully. The modeled results based on the surface renewal theory demonstrate a good agreement with experimental data.