A self-cleaning piezoelectric PVDF membrane system for filtration of kaolin suspension
A self-cleaning piezoelectric PVDF membrane system for filtration of kaolin suspension
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DOI：
10.1016/j.seppur.2018.12.082
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发表时间：
2019-05-15
影响因子：
8.6
通讯作者：
Pomalaza-Raez, Carlos
中科院分区：
文献类型：
--
作者：
Chen, Dong;Pomalaza-Raez, Carlos
开发新型膜材料是缓解膜污染的重要途径。研究了一种自清洁的聚偏氟乙烯（PVDF）压电膜系统，该系统可以在控制的频率、振幅和波形下振动，以减轻膜污染。在不同的PVDF薄膜中，选择了β相含量最高的PVDF薄膜，因为其压电系数最大。将膜针刺成0.14 +/-0.02mm的孔用于过滤目的。振动速度和振幅的特征峰被识别的测量与分层驱动电压的扫描激光多普勒测振仪。在34.5 kPa的恒定过滤压力下，在用0.5 g L-1 Z-平均直径为907.7 nm的高岭土悬浮液进料的死端过滤系统中测试压电膜。结果表明，振动速度比振幅更重要的选择振动频率，以优化膜污染控制。由24 V（峰-峰）和频率为1601 Hz（振动速度峰值）的正弦波驱动的连续振动的压电膜产生比对照测试高87 +/-3%的渗透通量，相比之下，在664 Hz（振动振幅峰值）的频率下增加30 +/-3%。然而，间歇性振动的振动效果并不明显，这可能是由于清洁和防结垢过程中断。对清选的机理解释表明，水力剪切产生的升力比振动产生的惯性升力更重要。
Exploring innovative membrane material is an important approach to mitigate membrane fouling. This study investigated a self-cleaning polyvinylidene fluoride (PVDF) piezoelectric membrane system which can vibrate at controlled frequencies, amplitudes and waveforms to mitigate membrane fouling. Among different PVDF films, the one of the highest content beta-phase PVDF was selected because of the greatest piezoelectric coefficient. The film was pin punched to 0.14 +/- 0.02 mm holes for filtration purpose. The characteristic peaks of vibration velocity and amplitude were identified by measurements of a Scanning Laser-Doppler vibrometer with tiered driving voltages. The piezoelectric membrane was tested in a dead-end filtration system fed with 0.5 g L-1 kaolin suspension of 907.7 nm Z-average diameter at a constant filtration pressure of 34.5 kPa. The results indicate vibration velocity is more important than amplitude to choose the vibration frequency in order to optimize membrane fouling control. The piezoelectric membrane with continued vibration driven by 24 V (peak-to-peak) and sine wave at the frequency of 1601 Hz (the peak of vibration velocity) yielded 87 +/- 3% higher permeate flux than control test, compared to 30 +/- 3% increase at the frequency of 664 Hz (the peak of vibration amplitude). However, the antifouling effect was not apparent with intermittent vibration, possibly due to interrupted processes of cleaning and fouling prevention. The mechanistic explanation of cleaning suggests lift force brought by hydraulic shearing is more important than inertial lift force of vibration.