Recovery of acetic acid from wastewater using supported liquid membrane

Wastewater contains abundant small molecular acids such as acetic acid, but current treatment methods mainly focus on degradation, lacking effective means for recovery. In this study, we propose the use of supported liquid membrane (SLM) for the separation and recovery of organic acids in wastewater treatment. By optimizing the formulation of the liquid membrane and selecting the supporting matrix, we successfully constructed the SLM with superior performance for acetic acid separation, the acetic acid recovery efficiency could be stabilized at over 90 % after 9 hours. The effects of pH, recirculation flow rate, inorganic salt, and organic matter on the separation of acetic acid by this system were investigated and discussed. The primary driving forces for the separation of acetic acid in SLM are the chemical potential gradient and the concentration difference created by the pH difference, and the reaction mechanism and kinetics of this process were thoroughly analyzed. In the performance tests, the SLM exhibited excellent long-term operational stability and regenerative capacity, showing no decline in acetic acid recovery performance after five regeneration cycles. Furthermore, it demonstrated broad applicability for the recovery of various organic acids. Overall, this novel SLM system provides an effective strategy for recovering small organic acids from wastewater, facilitating their resourceful utilization.