Abstract: mCMC-PEG-CS bipolar membrane(BM) was prepared by cation and anion exchange membrane. Cation exchange membrane was prepared with polyethylene glycol(PEG)-sodium carboxymethyl cellubse(CMC) blends which were modified by Fe³⁺, and anion exchange membrane was prepared by PEG-chitosan(CS) blends which were modified by glutaraldehyde(GA), rspectively. mCMC-PEG-CS bipolar membrane was used as a separator in the electrolysis cell to produce thioglycolic acid(TGA). Thioglycolic acid(TGA) was prepared by electro-reduction of dithioglycollic acid(DTDGA) with the mixture of TGA and DTDGA as the raw materials. The influences such as acid concentration, temperature and electrolysis current densities on the electro-generation and the current efficiency of TGA were studied. The experiment results show that TGA was prepared effectively by electroreduction of dithioglycollic acid(DTDGA) with the mixture of TGA(2.79%) and DTDGA in the cathodic room. The current efficiency was up to 74.69% at 35 ℃ in a cylinder electrolysis cell at 10 mA/cm². To compare with the traditional of metal reduction method, the electro-reduction technology saves the zinc powder and eliminates the pollution to environment.

Key words: mCMC-PEG-CS Bipolar membrane, Thioglycolic acid(TGA), Electro-reduction, Dithioglycollic acid(DTDGA)