application of response surface methodology for optimazation of PVDF hollow fiber membrane in DCMD and AGMD performance

Polyvinylidene fluoride (PVDF) hollow fiber membranes were prepared by the dry/wet jet spinning phase inversion technique. the Box-Behnken design method were applied for study the fibers under different polymer concentrations, BaCl2 salt concentrations and air gap length to optimize mean outer surface pore size, overall porosity and hydrophobicity. The prepared membranes were characterized through SEM observation and contact angle test. An optimal hollow fiber membrane was finally fabricated using the determined optimum spinning conditions: polymer concentration of 22 %w/w, BaCl2 concentration of 2.9 %w/w and air gap of 34.5 cm. The optimum fiber was tested for desalination by direct contact and air gap membrane distillation (DCMD and AGMD). The permeate flux of this fiber at different concentrations and temperatures of feed was tested for comparison. At optimal MD condition (feed concentration of 0.5 mol/lit and temperature of 80 °C), optimum fiber synthesis was compared with a fiber prepared at the same spinning condition but without salt additive. Permeation flux was improved in optimal fiber from 13.750 kg/m2.hr to 20.101 and from 10.212 to 13.367 with salt rejection of 99.9% for DCMD and AGMD respectively.

کلیدواژه ها:

Poly (vinylidene fluoride) ، Membrane distillation (MD) ، Hollow fiber ، Salt additive ، Desalination ، Box-Behnken method