Preparation and characterization of inexpensive kaolin hollow fibre membrane (KHFM) prepared using phase inversion/sintering technique for the efficient separation of real oily wastewater

Abstract

A low-cost kaolin hollow fiber membrane (KHFM) with unique finger-like and sponge-like structures was successfully fabricated by utilizing cheap and abundantly available kaolin clay as the starting material via phase inversion/sintering technique. In this study, mixing kaolin particles prepare the ceramic suspension, dispersant, polymer binder, and solvent using a planetary ball mill. This process is then followed by extrusion at various kaolin contents, bore fluid flow rates, and sintering temperatures ranging from 1200 to 1500 °C. The effect of calcium carbonate (CaCO3) content and polyethylene glycol (PEG) molecular weight as a function of pore agents are also discussed. Membrane characterizations were performed in terms of morphology, pore size distribution, porosity, mechanical strength, contact angle value, and pure water flux. The performance of membranes towards oil-in-water separation was conducted using oily wastewater samples taken from three points in Johor, Malaysia which were Kluang Oil Palm Mill Sdn. Bhd. in Kluang district, a car wash in Taman Skudai Baru in Johor Bahru district, and Meranti café, Universiti Teknologi Malaysia (UTM). The optimum parameters in fabricating the inexpensive KHFM were identified. It was found that the increase of kaolin content, bore fluid flow rate, and sintering temperature gave insignificant effect in the formation of finger–like structure but the process can be used to find a defect-free (i.e., rounded lumen and sufficient thickness) hollow fiber membrane shape. Interestingly, the finger-like structure can be controlled by the addition of PEG as a pore agent at different molecular weights. KHFM prepared with PEG 30,000 as a pore agent offered the highest oil rejection of 99.99% of turbidity and total organic carbon (TOC), and 91.8% of chemical oxygen demand (COD) with stable high flux of 320 L/m2h for all oily wastewater samples.