The Experimental Study Of Liquid Membrane In The Process Of Penicillin G Recovery

Penicillin G (PG) is a widely used antibiotic and also serves as an important raw material for semisynthetic penicillins. During traditional physical solvent extraction of PG from filtered broth , the lost of PG are considerable at pH values of 1.8-2.2. A low temperature of 0 to 5℃must be applied and expensive centrifugal extractors are necessary for the phase separation in extraction. Liquid membranes (LM) technical is a alternative which can combine extraction and back-extraction processes in one step. With the the advantages of high mass transfer efficiency and good selectivity, liquid membrane has become one of the most advantageous techniques in the purification and separation biochemical products such as penicillin G.In this work, Bulk liquid membrane (BLM) and a new liquid membrane, named hollow fiber renewal liquid membrane (HFRLM ) were applied to study the separation of penicillin G. The following achivedment were gotten in this work:A HPLC method for penicillin G determination in its solvent extraction process was established. 0.2 mol·L^-1 KH₂PO₄ (pH=3.5)—methanol (38:62) was chose as the mobile phase. The method is rapid, accurate and reliable and the influence of buffer and organic solvents can be omitted. Several kinds of extractants were used to study the extraction behavior with different pH, temperature, carrier content, diluent. The patition coefficients of physical extraction processes was higher but considerable PG were lost. Reactive extraction process can be conducted under mild pH (5-7) and room temperature.Bulk liquid membrane experiment was performed to testify the feasibility and advantages of liquid membrane in penicillin G separation. The effects of operation mode, flow rate, carrier concentration, pH on the mass transfer performance of HFRLM were determined. The pH difference between the feed and strip is the main driving force during the mass transfer process of penicillin G.HFRLM has both good extraction and concentration efficiencies for penicillin G. The extraction in the feed reached 99.2% and the recovery in the strip was 92.2% in the circulated experiments with a initial concentration of 50000 u. During the simulated process with HFRLM to separate high concentration (100000 u) feed, the recovery of penicillin G can reach above 88% after 8 stages HFRLM operation.