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Recent Development in Nanomaterials: Industrial Scale Fabrication and Applications
Published in Uma Shanker, Manviri Rani, Liquid and Crystal Nanomaterials for Water Pollutants Remediation, 2022
Ankita Dhillon, Meena Nemiwal, Dinesh Kumar
Suitable shape, size, temperature, appropriate solvent, and reducing/capping agent need to be well-thought-out for the synthesis of PtNPs. Aggregation can be avoided by this method. The inexpensive nature of the process, ease of functionality, adaptable surface chemistry, thermal stability, high production, low dispersion, and size-controlled synthesis are various chemical methods. The employment of harmful chemicals and organic solvents and reduced purity are downsides of chemical methods. Several studies have reported the chemical synthesis of PtNPs (Yuan et al. 2020, Wu et al. 2021, Quinson et al. 2021, Rondelli et al. 2017) that involved three critical modules for the fabrication are metal salt solutions, capping or stabilizing reagents, and reducing agents. Colloidal solution of PtNPs is produced by chemically reducing the metallic ion using a suitable reducing agent (Figure 4) (Jeyaraj et al. 2019). Sodium borohydride, elemental hydrogen, potassium bitartrate, trisodium citrate, and ascorbate are commonly used reducing agents. The reaction temperature (Shameli et al. 2010), a reducing agent (Salvador et al. 2021), and the concentration of the precursor (Figure 5) determines the morphology of the synthesized PtNPs (Jeyaraj et al. 2019).
Introduction to Membrane Processing
Published in M. Selvamuthukumaran, Applications of Membrane Technology for Food Processing Industries, 2020
Carole C. Tranchant, M. Selvamuthukumaran
ED is a technology of choice for the concentration and separation of ions and charged molecules from aqueous solutions. Commercial applications of ED with monopolar membranes include desalination (seawater, brackish water and industrial wastewater), water demineralization, as well as the separation and concentration of various substances such as organic acids (e.g., lactic acid and citric acid) and ammonium sulphate in the biochemical, biotechnological and pharmaceutical industries (Moresi and Sappino, 1998; Warsinger et al., 2016; Wee et al., 2005). ED was recently found to be an economically promising technology for the recovery of nitrogen from wastewater (Ward et al., 2018). In the food industry, ED with monopolar membranes has found numerous applications in the processing of dairy products, wines and fruit juices, as well as in the treatment of food processing effluents and byproducts, for instance, demineralization of distillery vinasse, desalination of mussel cooking juice and recovery of bioactive peptides from crab byproducts (Kotsanopoulos and Arvanitoyannis, 2015; Nazir et al., 2019) (Table 1.3). Applications in the dairy industry include the demineralization of whey and skim milk. In winemaking, ED is applied to stabilize wines by removing potassium bitartrate (Fidaleo and Moresi, 2006; Mikhaylin and Bazinet, 2016).
Tracers
Published in Werner Käss, Tracing Technique in Geohydrology, 2018
The first indication that yeast could be used as a tracer came from Miquel (1901). He obtained good results in the Cretaceous karst in the Avre and Vanne regions (Picardie/Northern France). There, up to 40 kg of yeast from breweries were diluted 10 to 20 fold and injected in the underground. The yeast was detected in springs and wells over distances between 10 and 15 km. Miquel also observed that the yeast cells survived in water pipes for over two months and at distances of over 100 km. Miquel tested for yeast thus: The freshly taken water samples are poured into small flasks and an acidic peptone-sugar-bouillon (200 g saccharose + 1 g tartaric acid + some potassium bitartrate) added and kept at 25°C. If yeast is present, after 24 and 48 hours spots or colonies of Sxerevisiae will form on the flask bottom under heavy alcohol formation. If this procedure is followed, any lactic acid bacteria possibly present will not develop until later, they can however overgrow the whole bouillon.
Catalysts used in biodiesel production: a review
Published in Biofuels, 2021
Since the optimization of the catalysts requires an increase in the number of active sites in order to increase the specific surface area, the size of particles should be decreased. Modern catalysts usually contain multi-component active phases and these phases may include a suitable base that gives rise to unique properties in the catalyst particles [93]. As such, increased surface area-to-volume ratio can be a key feature of nano-catalysts. Smaller objects have a larger surface area than their volume [100]. Furthermore, a catalyst can increase the speed of a reaction in three ways: it can reduce the activation energy in a given reaction; it may function as a facilitator; and when two or more products are formed, the catalyst tries to increase the reaction efficiency of a specific component. Depending on the application in question, nano-catalysts can be used in all of these ways. Nano-catalysts are more effective than ordinary catalysts for the following two reasons: first, their ultra-small size (10–80 nm) leads to a significant surface area-to-volume ratio. Second, when materials come in nano-sized quantities, they acquire properties that do not reside in macroscopic size [5]. It has also been shown that the size of and distance between nano-particles have significant impacts on their catalytic activities and selectivity [91]. Different solid nano-catalysts have been tested in biodiesel synthesis, such as amorphous alumina nano-particles, K2O/γ–Al2O3, hydrotalcite particles, mixed oxide SiO2/ZrO2, Fe3O4, amino-silane modified Fe3O4, Ca/Al/Fe3O4, KF/γ–Al2O3, potassium bitartrate on zirconia support and Cs–CA/SiO2–TiO2 [99–111].