Preparation of low-cost silicate-based microfiltration membrane: Characterization, membrane fouling mechanism and antifouling performance

Abstract

A low-cost microfiltration membrane was prepared by utilizing silicate cement and pore-forming material at room temperature. The effects of pore-forming material content (2–10%, wt.) on membrane properties such as morphology, porosity, flexural strength, pore size distribution, permeability, chemical stability and antifouling properties were investigated. The optimized silicate-based microfiltration membrane (SFM) with 6% of pore-forming material content has a porosity of 20.3%, an average pore diameter of 0.74 µm, a flexural strength of 13.2 MPa and a water permeability of 2.33 m3·m−2·h−1·bar−1. The SFM had poor stability in the pH range of 1–3, while had good stability in the pH range of 5–10. The fouling mechanism was mainly the formation of cake layer according to the different plugging models through the SFM pollution test. The analysis of flux recovery ratio (FRR), total flux decline ratio (TFR), reversible flux decline ratio (RFR) and irreversible flux decline ratio (IFR) demonstrated that the SFM could be regenerated by cleaning with deionized water and 2 mg/L ozone solution. Compared with deionized water cleaning process, ozone solution cleaning could more effectively remove contaminants on the surface of SFM, and displayed favorable FRR of more than 90%. Finally, because of its promising properties and affordable cost, the developed membrane may be proposed as an alternative to conventional ceramic membranes for water purification.