Efficient separation and purification of trans-ferulic acid in fermentation broth based on a sulfonated graphene oxide/molecularly imprinted polymer composite membrane

Trans-ferulic acid (TFA) is a natural phenolic acid compound with anti-inflammatory, antioxidant and anti-tumor activities. Its efficient separation in complex biological fermentation broths is challenging. In this study, sulfonated graphene oxide (SGO)/molecularly imprinted polymers (MIP) composite membranes were prepared. Specific recognition sites were constructed using bifunctional monomers (methacrylic acid and acrylamide), and the membrane pore structure was regulated by non-solvent induced phase separation (NIPS), which enabled efficient separation of TFA. The results show that the SGO/MIP composite membrane prepared with mass ratio of SGO:MIP:polyvinylidene fluoride (PVDF):polyethylene glycol 2000 (pore-forming agent) of 0.9:0.225:12:0.72 has an adsorption capacity of 2249.31 mg/m² for TFA in the fermentation broth at 25 ℃, and a membrane flux of 53.94 L/(m²·h), indicating that it maintains good permeation performance while efficiently retaining target molecules. After gradient elution with 10%-60% (volume fraction) ethanol and recrystallization, the purity of TFA was 96.4% and the recovery rate was 87.17%. This study shows that the selective adsorption capacity of target molecules is significantly improved by introducing SGO and bifunctional monomer strategies, which provides a new idea for the large-scale separation of natural products.