A vibratory nanofiltration (NF) system was investigated in the preconcentration of coffee extracts for soluble coffee production. Four different NF membranes were studied, among which the selected membrane (Trisep Microdyn TS80) rendered the highest permeate flux and rejection efficiencies. The vibratory NF operation also considerably improved permeate flux, rejection efficiencies, and reduced flux decline from those observed in crossflow (CF) operation. Further, the effects of applied transmembrane pressure (TMP) and module vibrational frequency (F) at corresponding displacement (d) were investigated via response surface methodology in conjunction with a Box-Behnken experimental design, as to their interactions on the performance of the vibratory NF operation. Mathematical models were statistically determined from multivariate regression analysis on permeate flux, maximum surface shear rate, permeate quality, and rejection efficiencies. These correlations were also used to determine optimum conditions (TMP = 3.79 MPa, F = 54.7 Hz, d = 3.18 cm) to process 25.4 g L−1 coffee extracts. The observed responses from experimental verification were found to be in good agreement with the predicted values obtained by the reduced regression models.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Process Chemistry and Technology
- Filtration and Separation