Bauxite-based hollow fiber membrane for oilfield produced water treatment

Abstract

An advanced treatment technology of oilfield produced water (PW) is required because of the incapability of physical separation technologies to produce high quality treated water. Recently, hollow fiber membranes (HFMs) have been widely utilized since it is recognized as one of the most effective PW treatment technologies. However, membrane fouling is the main drawback of commercial polymeric membranes while commercial ceramic membranes are extremely expensive. Therefore, the aim of this research is to develop HFM from natural low cost ceramic material which is raw bauxite to counter these problems. The bauxite hollow fiber membranes (BHFMs) were developed using Malaysian raw bauxite with different bauxite loadings (45-60 wt.%) and sintering temperature (1250-1450 °C) via phase inversion and sintering technique. From the results obtained, BHFM with 50 wt.% of bauxite loading and sintered at 1350 °C showed the best morphological structure with sufficient mechanical strength of 135 MPa, suitable porosity value of 15.54 % and the medium average pore size of 0.78 |im. The BHFM also showed excellent water permeation of 195 L/m2.h.bar and 99% of oil rejection. The results of the contact angle revealed that the membranes are super-hydrophilic and super-oleophobic membrane. The fouled BHFM was further evaluated for its self-cleaning ability via ultraviolet (UV) driven photocatalytic test. The results showed the water permeation of the UV radiated BHFM increased by 30% compared to non-radiated BHFM. Then, the fouled BHFM was tested again for another two runs with the long term photocatalytic test to observe the efficiency of the self-cleaning properties. The result showed that the longterm study does affect the water permeability of the BHFM, which decreased to 169 L/m2.h.bar in the 3rd run of the self-cleaning test. The results of the oil rejection do not affect by the long-term photocatalytic test which stay in the range of 99%. The BHFM need some modification in the pore size of the membrane to maintain the self-cleaning properties. In conclusion, this study would provide a new insight on the application of BHFM as the cost-effective, self-cleaning membrane for the PW treatment.