Composite inorganic membranes containing nanoparticles of hydrated zirconium dioxide for electrodialytic separation

Abstract

The aim of the work was to elucidate the nature of charge-selective properties of macroporous composite inorganic membranes modified with nanoparticles of hydrated zirconium dioxide. The membranes have been investigated using methods of standard contact porosimetry, potentiometry, electron microscopy and small-angle X-ray scattering. The ion exchanger has been found to deposit inside pores of ceramics. Differential curves of pore volume distribution have been resolved using Lorentz functions; each maximum has been related to structure elements of the matrix and ion exchanger by means of calculations according to homogeneous and heterogeneous geometrical models. It was found that the voids, the radius of which is 4 to 8 nm, are responsible for charge selectivity of the composite membranes. These pores are formed due to blocking of macropores of ceramics with aggregates of nanoparticles of the ion exchanger; the radius of these aggregates is 20 to 24 nm. The membranes were applied to desalination of the solution containing NaCl. The removal degree of the salt from the solution reached 95% and 9% for the composite and unmodified membranes, respectively.

Ceramic anion-exchange membranes based on microporous supports infiltrated with hydrated zirconium dioxide

“…However, they are generally processed at high temperatures, retain a small number of xed ionogenic groups and lack of ionexchange properties. 16 Among the wide variety of ceramic compounds there are important exceptions, such as hydrated oxides of multivalent metals. For example, hydrated oxides of titanium and zirconium polymerize by oxolation and give rise to a dense structure with oxygen atoms at their surface that are not completely coordinated by metal atoms.…”

Enhanced Thermal Properties of Zirconia Nanoparticles and Chitosan-Based Intumescent Flame Retardant Coatings

“…Flame retardant materials are of two types: external and internal [19]. Flame can be inhibited by two methods: The first method is restricting the atmospheric oxygen from reaching the material by releasing non-combustible gases; and the second method depends on the thermal behavior of the flame retardant, which lead to reducing the heat at surface of the material and finally results in the extinguishing of the flame of the burning material [20]. Materials such as nitrogen, phosphorous, halogenated (organic), and non-halogenated (inorganic) substances or molecules can be used as flame retardant agents; these agents can increase the flame retardant properties of a material.…”

Whey desalination using polymer and inorganic membranes: Operation conditions

“…Inorganic membranes modified with hydrated oxides of multivalent metals possess ion exchange ability, charge selectivity, and chemical stability (10)(11)(12)(13). The aim of the investigation was to develop the operation conditions for highly-intensive electrodialysis of whey and nanofiltration permeate.…”