Titanium coating on ultrafiltration inorganic membranes for fouling control

Abstract

• Electrically conductive UF ceramic membrane. • Fouling control and prevention through periodic electrolysis. • Ti-coating on Al 2 O 3 through e-beam deposition process. • High water flux of about 700 LMH. • High flux recovery; reaching ˃90% of original value after the 1st cycle. Inorganic membranes hold great potential for various mainstream applications such as in wastewater treatment, drug manufacturing, food and beverage production, and dairy purification. There are numerous commercially available ceramic membranes which possess high corrosion resistance, high strength, and good heat resistance. However, these membranes are still prone to fouling causing a considerable decline in membrane performance and hence shorter life-times. Conventional methods for flux recovery include rigorous chemical backwashing, producing large amounts of sludge leading to disposal problems. In this work, commercial α-Alumina (Al 2 O 3 ) ultrafiltration (UF) membranes were coated with titanium through an e-beam deposition process. The titanium coating rendered the membrane conductive, without changing the superhydrophilicity and average pore size of the membrane. Thermal degradation profiles suggested good thermal characteristics of the membrane. Good electrocatalytic activity for hydrogen evolution reaction was observed for the membrane, with an over-potential of 450 mV and 400 mV vs. Reference Hydrogen Electrode in acid and base solutions. The conductive membrane allowed for periodic electrolysis which is a fast and simple technique for fouling control and prevention. The membrane was used as a cathode during a cross-flow filtration setup, where 2.0 V was applied for 5 min during intervals. Without electrolysis, a considerable decline in flux was observed reaching almost 10% and 40% of its original value during yeast and sodium alginate (SA) filtration respectively. However, substantial flux recovery to 87% and 97.5% was achieved after the first cleaning cycle during yeast and sodium alginate (SA) filtration respectively. Thereafter, considerable flux recovery was achieved during each subsequent electrolysis cycle. Membrane’s good electrocatalytic properties led to the generation of hydrogen bubbles which helped in sweeping away the foulants from the membrane’s surface.