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Adsorption on Activated Carbon: Role of Surface Chemistry in Water Purification
Published in Jayant K. Singh, Nishith Verma, Aqueous Phase Adsorption, 2018
Silver is commonly used as an antibacterial agent to protect a wide variety of products against bacteria, fungus, mold, and other microbes. Colloidal silver, mostly as silver nitrate or silver acetate, is an effective bactericide for water treatment. Colloidal silver in drinking water has also been used with some limitations. Two issues facing surface activation or modification of carbon with colloidal silver are leach-level and cost. In order to overcome these issues, several research studies are being carried out to introduce nano silver impregnation to minimize leach and also to bring down the cost. Very few companies have developed a unique nano silver impregnation process to address both issues associated with the conventional colloidal silver impregnation.
Effect of Nanoparticles on Gastrointestinal Tract
Published in V Ravishankar Rai, Jamuna A. Bai, Nanotechnology Applications in the Food Industry, 2018
Jamuna A. Bai, V Ravishankar Rai
The distribution of silver after 28 days of repeated oral administration of silver NPs and silver acetate was studied in rats. Ag NPs remained stable throughout the duration of the 28-day oral toxicity study. Besides the intestinal system, the largest silver concentrations were detected in the liver and kidneys. Silver was also found in the lungs and brain. Autometallographic staining showed cellular localization of silver in the ileum, liver, and kidney tissue in rats. TEM studies showed nanosized granules in the ileum of animals located in the basal lamina of the ileal epithelium and in lysosomes of macrophages within the lamina propria. EDX showed that the granules in lysosomes consisted of silver, selenium, and sulfur. However, silver granules were not seen in the liver (Loeschner et al. 2008).
Tuning the Properties of Silver Monolayers for Biological Applications
Published in Huiliang Cao, Silver Nanoparticles for Antibacterial Devices, 2017
Chemical precipitation is a convenient, environmentally friendly and safe method that may be conducted at mild temperatures with the use of various substrates. It occurs when an insoluble product is formed on the selected substrates as a consequence of a chemical reaction. Chemical precipitation involves the mixing of the precipitating agent with metal ions (e.g. silver ions derived from the dissociation of soluble silver slats such as silver nitrate or silver acetate) in a liquid medium, hydrolysis–condensation of hydrated ions and complexes (inorganic polymerisation) and their heteronucleation onto substrates. The nucleation and growth of particles can be adjusted by the controlled release of anions and cations. In turn, the precipitation kinetics is influenced by the reactant concentration, temperature and pH of mixtures. By controlling these factors, high-quality nanostructured films with desired architecture can be produced (Zhang 2010).
A review of hepatic nanotoxicology – summation of recent findings and considerations for the next generation of study designs
Published in Journal of Toxicology and Environmental Health, Part B, 2020
Ali Kermanizadeh, Leagh G Powell, Vicki Stone
Bergin et al. (2016) administered orally to two different Ag NMs (PVP or citrate-stabilized colloidal suspensions with median hydrodynamic diameters of 20 and 110 nm, respectively) at doses of 0.1, 1 or 10 mg/kg daily to male C57BL/6 mice (6-weeks-old) for 3 days. In these experiments, an additional silver acetate exposure group was included as the ionic Ag control. The animals were sacrificed on day 3 or 9 post final Ag NM exposure. Results demonstrated that between 70% and 98% of the administered Ag dose was recovered in feces, while particle size and coating did not significantly influence elimination of the NMs (peak fecal Ag detected 6–9 hr post-administration). Bergin et al. (2016) also showed that 0.5% of total administered dose was detectable in liver, spleen and intestines at 48 hr post final Ag NM administration. Finally, no hepatic histopathology was observed following the acute Ag NM exposure regime.
The complex puzzle of dietary silver nanoparticles, mucus and microbiota in the gut
Published in Journal of Toxicology and Environmental Health, Part B, 2020
Yuqiang Bi, Andrew K. Marcus, Hervé Robert, Rosa Krajmalnik-Brown, Bruce E. Rittmann, Paul Westerhoff, Marie-Hélène Ropers, Muriel Mercier-Bonin
Regarding the interplay of AgNPs with the intestinal microbiota, the conflicting results across preclinical studies using rodent models may be due to discrepancies in (i) size, coating, physicochemistry, and vehicle of AgNPs; (ii) the dose, duration, and mode of administration (oral gavage/food pellets supplemented with AgNPs); (iii) the rodent model (gender, age, number of animals per group, animal facilities-dependent microbiota); (iv) use of controls (e.g. ionic silver in the form of silver chloride (Das et al. 2014) or silver acetate (Williams et al. 2015); (v) sacrifice scheduling (immediately or 24 hr after the last gavage); and (vi) sample analysis, including method for microbiota detection (e.g. possible bias due to cultivation methods), and region of sampling (feces/ileum/cecum, mucosal/luminal microbiota). Few studies directly addressed the interplay. Therefore, this area of research needs to be further addressed by investigating indicators such as mucin expression, mucin/mucus composition, mucin O-glycosylation, thickness and physicochemistry/penetrability of the mucus network.
EUROCORR 2020: ‘Closing the gap between industry and academia in corrosion science and prediction’
Published in Corrosion Engineering, Science and Technology, 2021
D. J. Mills, D. Nuttall, L. Atkin
A poster by Romain Bodeux, EDF R&D, France, entitled ‘Analysis of aged photovoltaic modules’ summarised a study of the physical, chemical and microstructural changes which occur as PV modules degrade. Typically, only the photo-electric degradation of such modules is studied in degradation/accelerated aging tests. Aluminium black- field technology modules were studied, which are the most commonly used for power generation worldwide. The panels are made up of an encapsulated solar cell with a silver contact ‘finger’. The study found that when ethylene vinyl acetate (EVA) is used as an encapsulant, ingress of moisture and degradation of the EVA occurs. Galvanic corrosion occurs resulting in the formation of silver acetate, resulting in decreased performance of the panel with age.