title: Distribution and deposition of organic fouling on the microfiltration membrane evaluated by high-frequency ultrasound.
abstract: A 50 MHz high-frequency ultrasound and analysis method were developed to further improve the in situ assessment of deposition and distribution of organic fouling on the polyvinylidene fluoride (PVDF) membranes. Measurements of fouling depositions were performed from PVDF membranes filtrated with aqueous humic acid solutions (HAS) of 2 and 4 ppm concentrations in a flat-sheet module. Ultrasound signals reflected from the PVDF membranes, following filtrations at various durations including 0, 5, 15, 30, 60, and 100 min, were acquired. The thickness and distribution of fouling estimated and assessed by peak-to-peak echo voltage (Vpp) and C-mode images were found to be non-homogeneously deposited on the membranes. Following the filtrations with 2 and 4 ppm HAS for 100 min, the corresponding thickness of fouling deposition increased from 1.81±9 to 2.4571.57 mm, respectively; those averageVppdecreased from 2.05±07 to 1.13±16 V and from 2.11±08 to 0.94±15 V. These results demonstrated that the deposition and distribution of organic fouling could be sensitively and rapidly evaluated by high-frequency ultrasound image incorporated with the analysis method.
authors.affiliation: National Cheng Kung University, Department of Computer Science and Information Engineering, Institute of Medical Informatics and Medical Device Innovation Center, 1, University Road, Tainan 70101, Taiwan.
authors.forename: Yi-Hsun
authors.initials: YH
authors.lastname: Lin
authors.affiliation: Department of Chemical Engineering, National Taiwan University 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan ; R&D Center for Membrane Technology, Chung Yuan University 200, Chung Pei Road, Chung Li 32023, Taiwan.
authors.forename: Kuo-Lun
authors.initials: KL
authors.lastname: Tung
authors.affiliation: National Cheng Kung University, Department of Computer Science and Information Engineering, Institute of Medical Informatics and Medical Device Innovation Center, 1, University Road, Tainan 70101, Taiwan.
authors.forename: Shyh-Hau
authors.initials: SH
authors.lastname: Wang
authors.affiliation: NIH Ultrasound Transducer Resource Center, Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA.
authors.forename: Qifa
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: NIH Ultrasound Transducer Resource Center, Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA.
authors.forename: K Kirk
authors.initials: KK
authors.lastname: Shung
keywords: High-frequency ultrasound; Humic acid; Membrane fouling; Microfiltration