Evaluation of the performance of air micro-nano bubbles for cleaning in place to reduce the reverse osmosis membrane clogging
Ali Sharifi, Seyed Fazlolah Saghravani, Karim Ghasemipanah, Behnaz Dahrazma, Behnam Rasekh
Abstract
This paper investigates the effect of air micro-nano bubbles (AMNBs) on increasing the efficiency of the cleaning in place (CIP) process for reverse osmosis (RO) systems used in petrochemical industries. A membrane from the desalination unit was extracted as the test section over which surface have been formed various types of clogging. The test set-up included, a Lab-Scale Plate-and-Frame Module (LSPFD) accompanied by a micro-nano bubble generator. The ratio of permeate flux and salt rejection in four states before CIP, after conventional CIP, after treatment with AMNBs, and after the conventional CIP along with AMNBs were recorded as 24.4, 26.9, 25.1, 27.3 and 68.2, 77.4, 70.1, 81.8 %, respectively. Scanning Electron Microscopy (SEM) images and Energy Dispersive X-ray Spectrometer (EDS) analysis clearly show a notable reduction in clogging on the membrane when AMNBs are employed. Therefore, cleaning intervals of the industrial RO membranes increase resulting in the extension of their life-span.