Virus removal can be successfully achieved based on an
electrostatic
adsorption mechanism. The key requirement for this process is to develop
filter materials that can be produced by low-cost technologies and
are suitable in large-scale production for real applications. In this
study, we report development of spray-dried alumina granules modified
with copper (oxide) nanoparticles and critically assess the effect
of copper oxidation state on virus removal capacity. Using plate-shaped
alumina as a support material resulted in porous structure, which
in turn ensured prolonged contact time of contaminated water with
the material. Subsequently, copper (oxide) nanoparticles provided
a large number of adsorption sites. Flow experiments revealed that
copper(I) oxide and metallic copper were the active phases in virus
removal and 99.9% of MS2 bacteriophages could be removed. However,
almost no virus removal was observed in the presence of copper(II)
oxide. Contrasting virus removal characteristics are associated with
the different surface charge of copper species, as determined by zeta
potential measurements.
The commercially dominating technology for hydrogen production (i.e. steam methane reforming) emits large quantities of CO2 into the atmosphere. On the other hand, thermochemical water-splitting cycles allow to produce high purity H2 while simultaneously capturing CO2.
Chemical looping is a promising process to produce high purity H 2 while simultaneously capturing CO 2 . The key requirement for this process is the availability of oxygen carriers that possess a high cyclic redox stability, resistance to carbon deposition, and thermal sintering. In this study, ZrO 2 -supported Fe 2 O 3based oxygen carriers were developed using a coprecipitation technique. We assess in detail the influence of the key synthesis parameter, i.e., the pH value at which the precipitation was performed, on the morphological properties, chemical composition, local structure, and cyclic redox stability. The performance of the new oxygen carriers was compared to unsupported Fe 2 O 3 and Al 2 O 3 -supported Fe 2 O 3 . A higher degree of disorder in the local structure of oxygen carriers precipitated at low pH values was confirmed by X-ray absorption spectroscopy (XAS) measurements. Electrical conductivity measurements showed that supporting Fe 2 O 3 on ZrO 2 lowered significantly the activation energy for charge transport when compared to pure Fe 2 O 3 . In line with this observation, ZrO 2supported oxygen carriers displayed a very high and stable H 2 yield over 15 redox cycles when precipitation was performed at pH > 5.
The production of high purity hydrogen with the simultaneous capture of CO2, can be achieved through a chemical looping (CL) cycle relying on an iron oxide-based oxygen carrier. Indeed, the availability of active and cyclically stable oxygen carriers is a key criterion for the practical implementation of this technology. In this regard, improving our understanding of the reduction pathway(s) of iron-based oxygen carriers and the development of concepts to increase the reduction kinetics are important aspects. The aim of this work is to evaluate the effect of the addition of copper on the redox behaviour of iron oxide based oxygen carriers stabilized on ZrO2. In situ pulsed-H2 XANES (Fe K-edge) experiments allowed for the determination of the reduction pathways in these materials, viz. the reduction of both Fe2O3 and CuFe2O4 proceeded via a Fe2+ intermediate: Fe2O3 (CuFe2O4) → Fe3O4 (Cu0) → FeO (Cu0) → Fe0 (Cu0). In the first step CuFe2O4 is reduced to Cu0 and Fe3O4, whereby Cu0 promotes the further reduction of iron oxide, increasing their rate of formation. In particular, the rate of reduction of FeO → Fe0 is accelerated most dramatically by Cu0. This is an encouraging result as the FeO → Fe0 transition is the slowest reduction reaction.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.