Separation of volatile fatty acids (VFAs) from nutrients in food waste using membrane contactor: Analysis of VFA-membrane interactions, separation efficiency, and nutrient rejection

“Membrane surface properties and interactions with organic species can influence selective separation processes such as hydrophobic membrane contactors (HMC). The selective separation of volatile fatty acids (VFAs) from nutrients in industrial fermented food waste (FFW) was investigated using HMC. The focus was on (1) interactions induced by VFAs on membrane surface, (2) trends in membrane surface free energy (ϒStot), and (3) nutrient rejection (RNut) and VFA separation efficiency (Seff). The ϒStot and interactions varied with feed composition and concentration. The presence of VFAs increased the dispersive and polar interactions, and Lewis base components of the membrane surface by up to 2, 27, and 7-fold, respectively, while the Lewis acid components increased by three orders of magnitude. Consequently, the ϒStot tripled at maximum compared to the Control membrane, leading to decreased RNut and VFA Seff. The HMC separated 40–73 % of VFAs to the permeate while rejecting >95 % of nutrients in the feed. Increasing ϒStot above 36 mJ/m2 combined with decreasing water contact angle (WCA) below 90° were most detrimental to VFA Seff and RNut.”

(Citation: Francis Kotoka, Leonardo Gutierrez, Emile Cornelissen – Separation of volatile fatty acids (VFAs) from nutrients in food waste using membrane contactor: Analysis of VFA-membrane interactions, separation efficiency, and nutrient rejection –
Separation and Purification Technology 376(2025)Part 1, art. no. 133840 – https://doi.org/10.1016/j.seppur.2025.133840 – (Open Access))

© 2025 The Author(s). Published by Elsevier B.V. This is an open access article distributed under the terms of the Creative Commons CC-BY license