Hydrodynamic modelling of the filtration of molten metals through high-refractory cellular foam-ceramic filters

Abstract There is an urgent need for an effective and long-lasting ceramic filter for point-of-use water treatment. In this study, silver-diatomite nanocomposite ceramic filters were developed by an easy and effective method. The ceramic filters have a three-dimensional interconnected pore structure and porosity of 50.85%. Characterizations of the silver-diatomite nanocomposite ceramic filters were performed using scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Silver nanoparticles were confirmed to be formed in situ in the ceramic filter. The highest silver concentration in water was 0.24 μg/L and 2.1 μg/L in short- and long-term experiments, indicating very low silver-release properties of silver-diatomite nanocomposite ceramic filter. The nanocomposite ceramics show strong bactericidal activity. When contact time with Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) of 105 colony forming units (CFU)/mL exceeded 3 h, the bactericidal rates of the four different silver content ceramics against E. coli and S. aureus were all 100%. Strong bactericidal effect against E. coli with initial concentration of 109 CFU/mL were also observed in ceramic newly obtained and ceramic immersed in water for 270 days, demonstrating its high stability. The silver-diatomite nanocomposite ceramic filters could be a promising candidate for point-of-use water treatment.

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Direct Cladding from Molten Metals of Aluminum and Magnesium Alloys Using a Tandem Horizontal Twin Roll Caster

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.772.250 ◽

2015 ◽

Vol 772 ◽

pp. 250-256 ◽

Cited By ~ 5

Author(s):

Hideto Harada ◽

Shin Ichi Nishida ◽

Mayumi Suzuki ◽

Hisaki Watari ◽

T. Haga

Keyword(s):

Surface Condition ◽

Hardness Test ◽

Al Alloys ◽

Mg Alloy ◽

Al Alloy ◽

Molten Metals ◽

Electron Probe Micro Analyzer ◽

Twin Roll Caster ◽

Aluminum And Magnesium Alloys ◽

Twin Roll

This paper describes direct cladding of magnesium (Mg) and aluminum (Al) alloys using a tandem horizontal twin roll caster that has three pairs of upper and lower rolls. Manufacturing conditions that are appropriate for fabricating Al/Mg and Al/Mg/Al cladded material were investigated. The surface condition of the cladded cast strip was examined. An electron probe micro analyzer was used to observe the interface between Al alloy and Mg alloy. The thickness of the mixed layer of Al and Mg alloy was 15μm, and how the materials were connected was clarified. Microscopic observation and backscattered electron analysis were used to investigate the cladding mechanisms of the Al and Mg alloy layers. Average hardness was determined using the Vickers hardness test at the Al layer and at the diffused layer between Mg and Al alloys. Cladding of Al/Mg alloy and A/Mg/Al alloy was possible using a tandem twin-roll caster. In addition, Al3Mg2 and Al12Mg17 phase precipitation at the interface of the Al and Mg alloys was confirmed during direct cladding from molten metals.

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Antimicrobial Ceramic Filters for Water Bio-Decontamination

Coatings ◽

10.3390/coatings11030323 ◽

2021 ◽

Vol 11 (3) ◽

pp. 323

Author(s):

Olga Ferreira ◽

Patrícia Rijo ◽

João Gomes ◽

Ricardo Santos ◽

Sílvia Monteiro ◽

...

Keyword(s):

Biofilm Formation ◽

Methicillin Resistant Staphylococcus Aureus ◽

Environmental Risks ◽

Flow Conditions ◽

Industrial Systems ◽

Ceramic Filters ◽

Effective Strategies ◽

Human Health Risks ◽

Aquatic Medium ◽

Biocide Release

Bio-contamination of water through biofouling, which involves the natural colonization of submerged surfaces by waterborne organisms, is a global socio-economic concern, allied to premature materials bio-corrosion and high human health risks. Most effective strategies release toxic and persistent disinfectant compounds into the aquatic medium, causing environmental problems and leading to more stringent legislation regarding their use. To minimize these side effects, a newly non-biocide-release coating strategy suitable for several polymeric matrices, namely polydimethylsiloxane and polyurethane (PU)-based coatings, was used to generate antimicrobial ceramic filters for water bio-decontamination. The best results, in terms of antimicrobial activity and biocide release, showed an expressed delay and a decrease of up to 66% in the population of methicillin-resistant Staphylococcus aureus bacteria on ceramic filters coated with polyurethane (PU)-based coatings containing grafted Econea biocide, and no evidence of biocide release after being submerged for 45 days in water. Biocidal PU-based surfaces were also less prone to Enterococcus faecalis biofilm formation under flow conditions with an average reduction of 60% after 48 h compared to a pristine PU-based surface. Biocidal coated filters show to be a potential eco-friendly alternative for minimizing the environmental risks associated with biofouling formation in water-based industrial systems.

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