Preparation of supported zirconia ultrafiltration membranes with the aid of polymeric additives

Preparation of high-permeance ceramic microfiltration membranes using a pore-sealing method

A pore-sealing method for preparation of high-permeance alumina microfiltration (MF) membranes free of any intermediate layers is presented. It involves sequential coating of a polyvinyl butyral (PVB) layer and an alumina membrane precursor on the surface of the macroporous alumina support. An alumina MF membrane with no intermediate layers can be obtained on the support after pyrolysis of the PVB interlayer. The interlayer-free membrane prepared by this method has an average pore diameter of 0.26 μm and a water permeance of 1468 ± 81 L m^-2 h^-1 bar^-1 which is prominently higher than that of the ceramic membranes prepared with other techniques. The conspicuous increase of water permeance is speculated mainly due to the filtration resistance decrease of the interlayer-free ceramic membrane.

Preparation of high permeable alumina ceramic membrane with good separation performance via UV curing technique

The traditional dip-coating method for preparation of ceramic membranes requires a long drying time and easily produces drying defects. In this work, an improved dip-coating process was proposed. The UV curing technique was utilized to avoid crack formation and agglomeration of ceramic particles, for drying to be completed in a few minutes. Photosensitive resin and a photoinitiator were added into the aqueous ceramic suspension. Under the action of free radicals excited by ultraviolet light, a giant network formed in the green membrane within a short time which limits the migration of membrane particles. Experiments were performed to explore the influence of UV curing process on membrane properties and the optimum preparation conditions were obtained. Following a rapid drying treatment and firing, crack-free membranes were prepared, which exhibited a narrow pore size distribution centered at approximately 65.2 nm and a water permeance of 887 ± 48 L m⁻² h⁻¹ bar⁻¹. The largest pore size of the membrane was 85.7 nm while it could filter out 98.2% of the 100 nm monosize PS microsphere and the 60.1% of 60 nm, indicating its potential application in both membrane production efficiency and separation accuracy improvements.

The traditional dip-coating method for preparation of ceramic membranes requires a long drying time and easily produces drying defects. In this work, an improved dip-coating process was proposed.

A preparation method for the highly permeable ceramic microfiltration membrane – precursor film firing method

A new technique is proposed to improve the permeance of ceramic membranes.

Preparation and Characterization of Al2O3-Based Composite Membranes by Sol-Gel Method

Porous Al2O3-SiO2-ZrO2 ceramic composite membranes were fabricated by the sol-gel method. The effects of constitution of the composite sol, dip-coating parameters and calcination parameters on the morphology, phase composition, pore size distribution and BET surface area of the membranes were investigated extensively. The thermogravimetric analysis (TGA)/differential scanning calorimeters (TG/DSC), scanning Electron Microscopy (SEM), XRD analysis and N2 adsorption-desorption analysis was employed for the membranes characterization. TG/DSC curve shows that the suitable calcination temperature of Al2O3-SiO2-ZrO2 membranes is 1000°C. The SEM morphology displays a smooth and free-crack layer of Al2O3-SiO2-ZrO2 composite membranes on the surface of the support after calcination at 1000°C. Furthermore, the membranes were also successfully coated with a good adhesion to the support. The optimal composite membranes were obtained when the moral ratio of Al2O3-SiO2-ZrO2 was 10:2.3:1, the dip-coating parameters were four times dip-coating with every time of 60s respectively.

Preparation of a highly permeable alumina membrane via wet film phase inversion

Highly permeable alumina membrane has been prepared via wet film phase inversion. Orientated microtubular pores formed due to phase inversion of cellulose acetate.

Sol–Gel Synthesis of Alumina–Titania Nanostructure Membrane: Preparation and Characterization

In the present paper, the preparation and characterization of porous alumina–titania nanostructure membrane is described. The membrane layers consisted of an α-alumina membrane support, which was dip-coated with a composite alumina–titania top layer prepared in a sol–gel process. Thermogravimetric analysis showed that drying progress of the membrane layer is completed at about 560 °C. Scanning electron microscopy analysis displayed a smooth and defect-free layer of alumina–titania membrane after calcination at 600 °C. X-ray diffraction analysis showed the formation of gamma and orthorhombic alumina, brookite titania, and aluminium titanate (Al2TiO5) after the calcination step. Transmission electron microscopy analysis showed that the alumina–titania composite particle size was almost below 40 nm. The Brunauer–Emmet–Teller (BET) surface area, average pore size, and thickness of the membrane top layer were determined to be 292 m2/g, 2.2 nm, and 4 μm, respectively.