Treatment of oil/water emulsion by polyethylene glycol ultrafiltration membrane

摘要

Polyethylene glycol (PEG) membranes with different molecular mass cut-offs were used to treat oil/water emulsion, and the effects of experimental conditions including pressure, temperature and different operating modes on permeate flux and removal rate of chemical oxygen demand (COD_(Cr)) were studied. The results show that the permeate flux of ultrafiltration membrane is influenced by pressure and temperature; practical pressure is chosen to be 0.3 - 0.7 MPa for the PEG with molecular mass cut-offs of 8 000 and 0. 7 - 1. 0 MPa for the PEG with molecular mass cut-offs of 2 500; and the practical temperature is chosen to be 25 - 32℃. Different operating modes of ultrafiltration also influence the permeate flux and removal rate of COD_(Cr). The ultrafiltration membrane of intermittent cross-flow operating mode is easier to be influenced by blocky polarization and contamination than that of sequential cross-flow operating mode. Removal rate of COD_(Cr) in intermittent cross-flow and sequential cross-flow condition can be maintained at about 93%.