Recent Advances on Purification of Lactic Acid

With increasing interest in developing biodegradable polymers to replace fossil-based products globally, lactic acid (LA) has been paid extensive attention due to the high environment-compatibility of its downstream products. The mainstream efforts have been put in developing energy-efficient conversion technologies through biological and chemical routes to synthesize LA. However, to our best knowledge, there is a lack of sufficient attention in developing effective separation technologies with high atom economics for purifying LA and derivatives. In this review, the most recent advances in purifying LA using precipitation, reactive extraction, emulsion liquid membrane, reactive distillation, molecular distillation, and membrane techniques will be discussed critically with respect to the fundamentals, flow scheme, energy efficiency, and equipment. The outcome of this article is to offer insights into implementing more atomic and energy-efficient technologies for upgrading LA.