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Generation of Particles by Reactions
Published in Ko Higashitani, Hisao Makino, Shuji Matsusaka, Powder Technology Handbook, 2019
Kakeru Fujiwara, Sotiris E. Pratsinis, Hisao Suzuki
There are however certain disadvantages3, 10: 1.Capital investment is needed even for simple exploration of tiny quantities (hoods, controls, filters, etc.) 2.Safety must be closely observed as particles in gases can easily escape and be inhaled while operating at high temperatures requires close attention. 3.Low-cost precursor availability, preparation and handling is not always trivial. 4.Assuring product composition and uniformity requires thorough process design as on-line monitoring of particle characteristics is practically impossible during their large-scale manufacture. 5.Particles are typically more polydisperse than those made by wet-chemistry processes.
A review on synthesis and applications of versatile nanomaterials
Published in Inorganic and Nano-Metal Chemistry, 2022
G. N. Kokila, C. Mallikarjunaswamy, V. Lakshmi Ranganatha
The hydrothermal synthesizing method can change particle morphology and control grain size, surface chemistry, and crystalline phase by optimizing specific parameters such as the reaction temperature, pressure, solution composition, pH of the solvent, and surfactant and aging time.[52] Solvents chemical properties may boost the nucleation and grain growth; thereby influence the mass of the nanoparticles and their structure. The viscosity of the solvents can decide the size and chemical properties. By varying the pH of the solution, structural stability, composition, size, and morphology control can be done. The controlled temperature in the reaction mixture can vary the precursor’s solubility, stability, and chemical properties and procure the crystallization to encourage grain growth. The selection of precursors is significant because it can stabilize the structure and increase the chemical reactivity of the product.[53]
Recent progress in adsorptive removal of per- and poly-fluoroalkyl substances (PFAS) from water/wastewater
Published in Critical Reviews in Environmental Science and Technology, 2022
Most current treatment technologies (e.g., biological degradation, sonochemical degradation, ozonation, and chemical oxidation/reduction) are unable to energy-efficiently destroy PFAS due to their thermal and chemical stability (Rahman et al., 2014). Moreover, some redox treatments may result in shorter chained fluorinated by-products, whose toxicity is largely unknown (L. Xiao et al., 2019). Adsorption as a simple, effective, low-energy-demanding, economically feasible, and environmentally friendly technology is then considered a good option to address water contamination problems caused by PFAS (Kucharzyk et al., 2017). Although significant progress has been made in this regard during the last decade, more research efforts are still needed to solve the PFAS contamination issue, especially for the development of more effective and environmentally-friendly adsorbents (Du et al., 2014). To date, the mostly used adsorbents are activated carbons (ACs) and resins, which however are relatively expensive, limiting their use for field-scale applications (Nassi et al., 2014). Other new classes of adsorbents, such as minerals, polymers, and biomaterials, have been tested for PFAS removal (Rayne & Forest, 2009). Yet, their potential drawbacks of expensive precursor materials and complicated synthesis procedures have hindered their wide application. Besides, the effective adsorption of short-chained PFAS remains a challenge for most adsorbents (Kjølholt et al., 2015).
Synthesis of mesoscopic particles of multi-component rare earth permanent magnet compounds
Published in Science and Technology of Advanced Materials, 2021
T. Thuy Trinh, Jungryang Kim, Ryota Sato, Kenshi Matsumoto, Toshiharu Teranishi
The high negative reduction potentials of R cations, a large difference in reduction potentials of R and T cations, and high chemical instability of R metals make it impossible to directly synthesize R–T intermetallics by solution-phase chemical reactions. An alternative chemical synthetic approach is to first synthesize nanostructured precursors, which are chemically stable and readily synthesized by solution-phase reactions, followed by R–D reactions of the precursors. Monodisperse nanostructured precursors with controllable composition, size, and shape are an important key to determine the microstructure of MMPs, and they are advantageous depending on their structural fashions such as core@shell, encapsulated, doped, or mixed oxide NPs.