Rehabilitation of fouled membrane from natural rubber skim latex concentration through membrane autopsy and ultrasonication enhanced membrane cleaning procedure

Abstract

This study investigated the membrane foulants characteristics and cleaning protocol required for a poly vinylidene fluoride (PVDF) type, tubular cross flow 200 kD MWCO ultrafiltration membrane fouled during natural rubber skim latex concentration process. Chemical (alkaline and acidic solutions) and physical (ultrasonic application) cleaning procedures were conducted at room temperature of 28 °C and at an elevated temperature of 50 °C. The membrane permeability recoveries were obtained after the end of each membrane cleaning operation, by performing deionised water flux tests (DIWFT). The extracted chemical solutions were analyzed using total organic carbon analyzer and atomic absorption spectrophotometer to quantify organic and inorganic foulants, respectively. Fourier transformation infrared attenuated total reflection spectroscopy (ATR/FTIR) was used to examine the fouled membrane surface to determine the chemical nature of the foulants. The fouled and cleaned membrane surfaces were also examined using scanning electron microscopy (SEM). The SEM images and ATR/FTIR spectrums of fouled against cleaned membranes were used to determine the efficiencies of various cleaning procedures. The measured flux recoveries using DIWFT obtained after chemical cleaning at an elevated temperature of 50 °C were 93% and 89% with and without ultrasonic application, respectively.