Sericin Recovery from Silk Cocoon Degumming Wastewater by a Membrane Process

Abstract

Flat sheet asymmetric polymeric membranes were prepared from a homogeneous solution of polysulfone (PSF) in N-methylpyrrolidone by the phase inversion process with various concentrations and molecular weights of polydioxolane (PDXL) ( M_n = 10,000 Da and 200,000 Da) and polyethylene glycol (PEG) ( M_n = 300, 2000, 4600 and 10,000 Da) as the polymeric additives. The surface morphology of the prepared membranes was investigated. The performance of the prepared membranes was tested by their use in the recovery of sericin from silk cocoon degumming wastewater. The effects of polymeric additives and transmembrane pressures (200, 300 and 400 kPa) were studied in terms of the permeate
flux (PF), protein retention and molecular weight cut-off (MWCO) of sericin retention. Results showed that the PF and MWCO of the permeate increased but protein retention decreased with increasing concentration, molecular weight of both polymeric additives and transmembrane pressure. Hence, it clearly revealed that the morphological parameters and flux performance of the membranes have a significant inter-relationship with the concentration, molecular weight of both polymeric additives and transmembrane pressure.