Effects of collapsible-tube-induced pulsation vigour on membrane filtration performance

Pulsatile microfiltration experiments with bentonite suspension (0.5 g/l) were performed in a ceramic tubular membrane (0.2 μm). The pulsatile flow was generated by the self-excited oscillation of a collapsible tube. This study investigated the effects on microfiltration performance of varying the vigour of the pulsation, while the time-averaged transmembrane pressure and crossflow velocity remained constant at 100 kPa and 1.5 m/s. The pulsation was highly non-sinusoidal; vigour was associated with pulsation size. Depending on the collapsible-tube settings, up to 300% permeate flux enhancement and up to 87% reduction in backflushable resistance were observed, relative to steady microfiltration conducted at the same transmembrane pressure and crossflow velocity. Although irreversible resistance became much larger than in steady microfiltration, it still did not dominate overall resistance. The retention was slightly lowered in pulsatile flow. Two mechanism-related pulsatility parameters were used to explain the basis of the performance changes.