This invention discloses a method for pretreating L-lactic acid fermentation solution with magnetic polymer by flocculation. The magnetic polymer is prepared from chitosan and ferroferric oxide in a weak acid condition. The method comprises: adding the magnetic polymer into L-lactic acid fermentation solution, stirring so that a flox occurs, applying a magnetic field for 1-2 min to separate the floc from the solution, and removing the floc to obtain L-lactic acid fermentation solution. The method has such advantages as simple process, high flocculation rate, compact floc structure, rapid solid-liquid separation, high treating efficiency and no influence on L-lactic acid content in the fermentation solution. The method has potential applications in the pretreatment of L-lactic acid fermentation solution. |