Synthesis of alumina, titania, and alumina-titania hydrophobic membranes via sol?gel polymeric route

Abstract

Nanometer TiO 2 -Al 2 O 3 composite membranes were synthesized through the sol-gel polymeric reaction of TiCl 4 and AlCl 3 in the presence of acrylic-acrylamide copolymer as a template. The dried samples were characterized by DTA, TGA, FTIR, XRD, and TEM to determine the thermal behavior, chemical composition, crystal structure, shape, and size of the particles. Octyltrichlorosilane was chosen as a silane coupling agent to increase the hydrophobic nature of the prepared membranes. The morphological structure, hydrophobic nature, water permeability, and desalination efficiency of the prepared membranes were studied by SEM, contact angle, permeability, and NaCl rejection coefficient (R%) measurements. The crystal structure of titania and alumina particles in the composite was affected by the AlCl 3 and TiCl 4 feed ratio. As the titania concentration increased, the average particle size of the composite particles became larger and the uniformity of the membrane layer decreased. The alumina (75%)-titania (25%) composite (AT25) showed a uniform crack-free membrane layer with a pore diameter of 12.9 nm and a porosity of 21.46%, with great hydrophobic nature, and with contact angle reaching 116°. This membrane can withstand calcination temperature up to 700°C, as the alumina and titania were present in their active forms: gamma-alumina and anatase, respectively. The membrane produced from this composite showed a high surface area of 333 m 2 /g with a respective particle size of 4.6 nm. Moreover, it showed a high ability to reject NaCl from water with a rejection coefficient of 73% and a high permeation flux of 4.8 l/h m 2 at 75°C.

Effect of Calcination Temperature on the Silica Ceramic Membrane Synthesized via Sol-gel Dip-Coating Method

“…The broad band in the region range between 1060 to 1090 cm -1 correspond to the O-Si-O bond of mesoporous silica, altogether verify the existence of silica. IR adsorption at 791.4 cm -1 shows the modification of Si-CH3 group on the silica ceramic membrane surface as mentioned by Bowen et al [9].…”

Alumina-Activated Carbon Composite as Adsorbent of Procion Red Dye from Wastewater Songket Industry

“…Meanwhile the remaining of C-H stretching for methyl or methylene group were recorded at 3317.8 cm -1 for the activated carbon, and at 3328.9 cm -1 for the resulted of alumina-activated carbon composite. The characteristic spectra FTIR for alumina, can be assigned 624-659 cm -1 is the uptake group C-O-R + , where R + is Al 3+ [13]. This peak appears at 611.4 cm -1 .…”

Corrosion Protection of Aluminum Metal Using MCM-41 Films Supported by Silver Nanoparticles and Distyrylpyrazine Photopolymer

“…In order to eliminate the creak defects in the coating and to optimize the coating structure and properties, the Al/MCM-41 electrode was immersed in boiling water for 10-50 min, and then thermally treated in a muffle oven again at 450 C for 10 min. 23 In order to eliminate the cracks and other defects, various additives such as polyethylene glycol PEG, polyvinyl alcohol (PVA), 24 and hydroxypropylcellulose (HPC) 25 are reported to be added into the colloidal solution to improve the drying properties of the gel, adjust the viscosity of the sol, and increase the strength of the material to prevent crack formation. 26…”