Phytic acid is mainly extracted from rice bran and grain by‑products. Conventional processes such as plate‑and‑frame filtration and thermal evaporation suffer from incomplete impurity removal, thermal degradation of active components, high energy consumption and unstable product purity. Membrane separation works at ambient temperature via physical sieving. Ultrafiltration removes colloids and protein impurities, while nanofiltration realizes concentration and desalination simultaneously. It improves clarity, purity and recovery rate, becoming a preferred solution for food‑grade and pharmaceutical‑grade phytic acid production.