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In situ monitoring of membrane fouling and cleaning in spiral-wound RO modules by Ultrasonic time-domain reflectometry
Authors: AN Genghong1, LIN Jiebin1, LI Xianhui1, LI Jianxin11*, JIAN Xiqi2, JING Dawei3
Units: 1. State Key Laboratory of Hollow Fiber Membrane Materials and Processes, School of Material Science and Engineering, Tianjin Polytechnic University, Tianjin 300160, China;2. Tianjin Medical University, Tianjin 300070, P.R. China;3. Center for Membrane Technology, Tianjin Institute of Urban Construction, Tianjin 300384, China
KeyWords: ultrasonic time-domain reflectometry (UTDR); spiral-wound membrane module; reverse osmosis; membrane scaling and cleaning; sound intensity
ClassificationCode:TQ028
year,volume(issue):pagination: 2012,32(1):87-92

Abstract:
The study describes the ultrasonic time-domain reflectometry with a sound intensity model for monitoring membrane scaling and cleaning in a spiral-wound reverse osmosis element. Three focused transducers with the frequency of 2.25 MHZ and the commercial spiral-wound RO module were used. The scaling experiments were carried out with 1.0 g/L calcium sulfate and the cleaning process consisted of three different phases: pure water flushing, immersion cleaning and acid-washing. Results showed that the ultrasound generated by the focused transducer is capable to penetrate through the multiple layers of membrane. The systematic changes in ultrasonic signals had also been observed during the fouling process. The results of sound intensity revealed that the corresponding sound intensity gradually decreased to minimum with the deposition of the foulant on the membrane and then kept constant as the formation of fouling layer. Further, with different initial lag phases on different ports, the scaling gradually deposited and more and more along the feed flow direction with the fouling process due to concentration polarization. Moreover, the membrane flux and sound intensity recovered step by step with the cleaning processes. The results obtained by independent methods were in good agreement with the observations by ultrasonic technology.
 

Funds:
国家自然科学基金资助项目(20876115)

AuthorIntro:
安耿宏(1984-),男,山西省忻州市人,在读硕士,从事膜分离及水处理技术研究. *通讯联系人:022-24528072,〈jxli0288@yahoo.com.cn〉

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