Surface Modification and Performance Enhancement of Polyethersulfone (PES) Membrane Using Combination of Ultra Violet Irradiation and Thermal Annealing for Produced Water Treatment

摘要

Background: Produced water is waste water from crude oil production process. A large volume of water is produced during operation as a by-product. This volume is expected to increase from maturing conventional oil and gas fields. Due to its hazardous contents, produced water needs to be treated before disposing to the environment or being utilized. Materials and Methods: The membrane was prepared by casting a stable and homogeny dope solution containing 19% weight polyether sulfone and 81% weight n-methyl-2-pyrrolidone using dry/wet phase inversion technique. The performance of the membrane was investigated as effects of set of variables: UV irradiation (10, 25 and 300 sec), annealing temperature (150 and 180°C) and annealing time (10, 25 and 60 sec). Permeation test was used to investigate flux and rejection, SEM analysis was used to observe the morphology of the membrane and FTIR analysis was employed to investigate the functional group contained in the membrane. Results: Flat sheet PES membranes were successfully fabricated via dry/wet phase inversion technique. Subjecting the membrane under UV irradiation for 300 sec showed the highest flux of 38 L h^?1 m^?2 bar^?1. The annealing treatment to the membrane at 180°C for 10 sec performed the highest rejection efficiency of 76% as S^2? rejection, 70% as TDS rejection and 65% as Ca²⁺ rejection. Cross-sectional SEM images showed the asymmetric and finger-like structure, the surface images showed no voids could be observed. The FTIR spectra analysis showed the formation of hydrophilic functional group as an effect of UV irradiation on the membrane surface. Conclusion: The PES membrane was successfully modified using UV irradiation and thermal annealing treatment. The UV irradiation on the membrane for 300 sec and thermal annealing at 180°C for 10 sec significantly increased the flux and rejection.