Very efficient composite titania membranes in hybrid ultrafiltration/photocatalysis water treatment processes

Prototype composite membranes of partially reduced graphene oxide/TiO2 for photocatalytic ultrafiltration water treatment under visible light

“…The hybrid photocatalytic/membrane filtration processes took place in a photocatalytic purification device, which has been described in detail elsewhere [21]. In brief, the purification device allowed to determine the performance of photocatalytic tests in the cross-flow and dead-end filtration mode with irradiation applied on the shell side surface of the single channel monolith.…”

“…In former studies of our group, CVD derived double sided active photocatalytic ceramic ultrafiltration (UF) membranes were employed for organic dye removal from wastewater [18][19][20][21]. The innovative hybrid photocatalytic/UF process involved the filtration of polluted water in the cross-flow or dead-end membrane configuration, with UV irradiation applied on both photocatalytically active surfaces of the membranes.…”

“…The overall concept and method of implementation into an efficient water purification device are already protected by a European patent [22]. When compared to the standard nanofiltration (NF) with ceramic membranes, the hybrid photocatalytic/UF process achieved five times higher pollutant removal efficiency while performing with the same water recovery [21]. Most important, due to the low trans-membrane pressure, the energy expense (kW h/m 3 ) of the pump feeding the water stream in the membrane module was almost half the energy usually spent in NF.…”

“…The concern is clearly depicted in Fig. 1, where the energy consumption of a CVD derived photocatalytic ceramic membrane [21] is compared with the standard NF and reverse osmosis (RO) processes. When applying three or more UVA light sources of 8 W each, with the purpose to achieve sufficient irradiation density on the photocatalytically active membrane surface, the total energy consumed for treating the same amount of water exceeds that required in a typical NF process, and in some cases it is equal to that of the most energy demanding RO.…”

Chapter Green Nanotechnology: Development of Nanomaterials for Environmental and Energy Applications

“…Finally, composite carbon nanotubes/titania nanostructures were developed on well-aligned carbon nanotubes (CNTs) produced by means of chemical vapor deposition (CVD) using surfactant-stabilized Fe 3 O 4 particles and anodized alumina disks as templates. All these innovative approaches have been implemented by integrating extensive R&D efforts spanning a wide range of interdisciplinary activities from the development of novel nanomaterials and membranes to reactor engineering and analytical methods for water pollutants of emerging concern as well as pilot plant scale studies and cost analysis for water purification (95)(96)(97).…”