Experimental aspects of ultrasonically enhanced cross-flow membrane filtration of industrial wastewater (original) (raw)

2006, Ultrasonics sonochemistry

Ultrasound based on-line cleaning for membrane filtration of industrial wastewater was studied. An ultrasonic transducer was assembled in the membrane module in order to get an efficient cleaning of membranes in fouling conditions. The focus of the studies was on the effects of the ultrasound propagation direction and frequency as well as the transmembrane pressure. The more open the membrane was the easier the membrane became plugged by wastewater colloids, when the ultrasound propagation direction was from the feed flow side of the membrane. If the membrane was tight enough, the ultrasound irradiated from the feed side of the membrane increased the flux significantly. However, in the circumstances studied, the power intensity needed during filtration was so high that the membranes eroded gradually at some spots of the membrane surface. It was discovered that the ultrasonic field produced by the used transducers was uneven in pressurised conditions. On the other hand, the ultrasoun...

Effect of Ultrasound on Membrane Filtration and Cleaning Operations

Separation Science and Technology, 2012

The impact of ultrasound (US) on membrane filtration and cleaning were studied and compared at various operating parameters of nominal pore sizes of 10 and 100 kDa membrane, trans-membrane pressure (TMP) of 100 and 140 kPa, and US frequencies of 20 kHz and 40 kHz. An average of 15%–20% increase of permeability was observed when US (20 kHz) was applied to assist membrane filtration on 10 kDa membrane and 100 kPa trans-membrane pressure (TMP). However, an insignificant improvement was observed in the case of larger pore size membrane at higher TMP (140 kPa). US also augmented the membrane cleaning process effectively. Lower frequency 20 kHz US exhibited a higher flux recovery (>90%) than the high frequency 40 kHz (59%) using the 10 kDa pore size membrane with US-assisted membrane cleaning. Important factors influencing optimization of US effectiveness lie heavily on its configuration and operation. The experimental results as supported with SEM images demonstrate that US-assisted filtration and cleaning are most effective when membrane pore size, US frequency, and TMP are lower.

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