Prediction of fouling resistance and permeate flux in cross-flow micellar-enhanced ultrafiltration (MEUF)

Cross-flow micellar-enhanced ultrafiltration had been used to separate pollutants from waste water effectively, while permeate flux decline with time because of the increase of fouling resistance. According to resistances in series theory, total transport resistance is the sum of two parts: membrane hydrodynamic resistance and fouling resistance. By observing material balance and hydrodynamic type of filtration, we proposed an analysis method of fouling resistance that was based on cross-flow filtration and took into account the presence of micelles instead of traditional cake resistance theory that was built from dead-end filtration. We found permeate flux decline not only by the relationship of time t1/2 that traditional cake resistance theory said, but also by concentration of fouling layer ϕ (or φ). Retentate non-recycled and retentate recycled cross-flow experiments were carried out under different operate conditions (i.e., transmembrane pressure (TMP) and initial concentration) by using artificial cadmium (Cd) contaminated water and sodium dodecyl sulfate (SDS) and models showed excellent accuracy to predict permeate flux through correlation r2 from 0.935 to 0.990.

The metal ions are absorbed in the surfactant micelles surface directly by electrostatic interaction. Simultaneously, charged cadmium ions bridged surfactant micelles that make micelles easier get together that form fouling layer.Figure optionsDownload as PowerPoint slideHighlights
► Models of cross-flow MEUF were built and showed excellent accuracy.
► Membrane hydrodynamic resistance is not a constant with different TMP.
► Not only TMP, initial concentration also affected specific fouling resistance.
► Not always higher TMP led to lower permeate flux.