Separation of organic acids by newly developed polysulfone microcapsules containing triotylamine

Newly developed polysulfone (PS) microcapsules containing triotylamine (TOA) were successfully prepared with a phase inversion method and the influence factors on the microcapsules have been investigated. The extraction performance of the microcapsules has also been carried out with oxalic acid, propionic acid and citric acid as solutes and the stability of the microcapsules was tested too. The results show that proper ethanol content in solidification solution, an optimal distance from pinhead to the surface of solidification solution and an appropriate emulsion composition are in favor of forming regularly spherical microcapsules. The prepared microcapsule has uniform outside surface and there is no apparent deficiency. The microcapsules have hollow structure and digital structure in their wall. Parts of TOA are immobilized in the wall with small particle form. The mass transfer rate and the uptakes to the organic acids are enough high. After seven times of repeated extraction and stripping, the microcapsules kept almost the same extraction ability, which indicated that the microcapsules have very good stability in the extraction process.