Temperature and durability studies of lactic acid dehydration with inorganic membranes

The use of lactic acid in product manufacture is growing due to its versatility, non-toxicity and environmentally benign source materials. One of the major costs in its production is the complex purification processes. The cost of such separation may be reduced by using simple dehydrating membrane technology. Inorganic membranes have been demonstrated in the past to effectively separate gases, and more recently for dehydration of aqueous solutions of alcohols. In this work, we demonstrate performance of high selectivity silica membrane for lactic acid dehydration. The membrane exhibited a H₂O selectivity factor of 63 after 300 minutes of continuous testing with flux stabilising at 0.76 kg.m^-2.hr^-1. Increasing operation temperature greatly improved flux to 5.8 kg.m^-2.hr ^-1. The minimum area required to dehydrate 1 l.min^-1 15% lactic acid feed to 85% was estimated in a simple single stage process model. At ambient conditions, 68 m² of membrane area was required, but upon heating to 80 C, this was reduced to 9 m². CTMSS membranes are ideal candidates for LA dehydration to reduce LA processing costs