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Hyper-crosslinked Polymers
Published in Inamuddin, Mohd Imran Ahamed, Rajender Boddula, Porous Polymer Science and Applications, 2022
Belén Arcentales-Vera, Lisandra Bastidas, Moises Bustamante-Torres, Paul Maldonado Pinos, Emilio Bucio
In an effort to seek low/non-polluting fuels to replace fossil fuels, hydrogen emerges as an efficient alternative. The use of hydrogen as a fuel has several benefits like its availability and a large amount of produced energy. Another advantage of hydrogen is that it is a clean source releasing only water as a by-product. Thus, hydrogen is an environmental-friendly alternative that offers the potential to reduce or eradicate carbon emissions from fossil fuels. Despite the numerous studies to develop adsorbent materials for hydrogen storage, safe storage is still a huge challenge (Tan and Tan 2017). One of the approaches to store hydrogen consists of using physisorption with porous polymers that possess large storage capacity and reversible sorption (Tan and Tan 2017). Surface area is a property that plays a crucial role in the adsorption behavior because a greater specific surface area indicates a high hydrogen adsorption capacity.
P
Published in Joseph C. Salamone, Polymeric Materials Encyclopedia, 2020
Dependence of composite properties on composition is a crucial question for the processing and application of these materials. The amount of filler necessary to achieve the optimum combination of properties must be always determined by experiments or by calculations, if the appropriate models are available. The modulus of PP composites increases with increasing filler content.31 Tensile properties (yield stress, tensile strength, elongation) and impact characteristics depend on composition in a more complicated way. These properties are said to decrease with increasing filler content in particulate-filled polymers, while at least stiffness and strength increase with filling in the case of reinforcements.32 In Figure 2 the tensile yield stress of PP composites is presented as a function of composition; the figure shows that true reinforcing can be achieved with particulate fillers as well. The figure also illustrates the effect of some particle characteristics; it is obvious that with decreasing particle size and increasing specific surface area, yield stress increases. The dashed line in the figure is the theoretical minimum of the yield stress. The effect of the specific surface area indicates that increasing contact surface (i.e., matrix–filler interaction) always leads to increased strength.
Solid State Testing of Inhaled Formulations
Published in Anthony J. Hickey, Sandro R.P. da Rocha, Pharmaceutical Inhalation Aerosol Technology, 2019
Philip Chi Lip Kwok, Hak-Kim Chan
A common method for measuring specific surface area is by adsorbing an inert gas (nitrogen or krypton) onto the surface of the sample (Lowell and Shields 1991). The experiment is conducted in a liquid nitrogen bath (77.4 K) because the amount of adsorbed gas at a given pressure increases with decreasing temperature (British Pharmacopoeia 2017, European Pharmacopoeia 2017, United States Pharmacopeia 40-National Formulary 35 2017). The gas molecules form layers on the particle surfaces by van der Waals forces. The volume of the adsorbed gas is then used to calculate the surface area with the Brunauer, Emmett, and Teller equation: () 1Va(PP0−1)=C−1VmC×PP0+1VmC
A review of technologies for bromide and iodide removal from water
Published in Environmental Technology Reviews, 2023
Silver-impregnated activated carbon and carbon aerogels have been proven excellent adsorbents for iodide and bromide [56,75–77]. The material with a higher specific surface area had better adsorption performance. Chloride and natural organic matter (NOM) had adverse effects on adsorption, and controlling the chloride-to-bromide ratio and the pore size of active carbon could reduce the impact [56]. However, silver-impregnated activated carbon has silver leaching problem, which will cause secondary pollution. Rajaeian et al. [74] found that, when the pH was 10.4, only 3% silver leaching and effective bromide removal could be achieved. Furthermore, silver chloride-impregnated activated carbon had less silver leaching and could remove more than 80% of bromide and 90% of iodide at pH 6.5 when the initial concentrations were both 1 mg/L [78].
Magnetically recyclable copper doped core-shell Fe3O4@TiO2@Cu nanocomposites for wastewater remediation
Published in Environmental Technology, 2022
Nisha Rani, Brijnandan S. Dehiya
Photocatalysis requires the dye degradation speed up by an ideal catalyst using light. Titanium dioxide is a familiar photocatalyst due to its many unique properties such as [22–24] chemical inertness, a strong oxidising agent, stability, and nontoxicity, etc. The photocatalytic dye degradation using TiO2 needs the illumination of titanium dioxide by light [25]. A variety of organic contaminants are targeted and oxidised by the hydroxyl radicals generated due to photocatalysis. It is interesting to use this material in wastewater treatment, especially for the degradation of contaminants in wastewater in industrial production. For the catalytic process, a huge specific surface area will benefit to improve the catalytic activity. Then nanoparticle materials will be attractive due to that their specific surface area is much larger than the coarse particles. Especially, when they are employed in the suspended state in liquids, a large surface area would significantly enhance the photocatalytic property. Though separation between TiO2 and wastewater turns out to be the main issue, where the photocatalytic powder can be wasted through taking apart procedure. However, if the employed nanoparticle materials cannot be withdrawn and reused, the cost for the processing would be very high. So it is imperative to develop new ways to withdraw the photocatalytic materials for reuse.
Magnetite-silica core–shell grafted myristic acid nanocomposites for oil adsorption from petroleum wastewater
Published in Journal of Dispersion Science and Technology, 2022
Amira K. Ibrahem, Mahmoud F. Mubarak, Mohamed Keshawy, Yasser Mohamed Moustafa, Mostafa Mohamed Khalil, Thanaa Abdel Moghny
The specific surface area is an important property that influences many aspects of reactivity, such as hydroxylation, dissolution, interaction with adsorbate molecules, and stability.[34] in this regard, the specific surface area, volume, and mean size of the adsorbent pores were determined using BET analysis; and, the findings are presented in Table 2 and Figure S3. It’s found that the maximum surface area of Fe3O4/SiO2@MA was 390 m2/g, taking into consideration that the reported magnetite range magnetite samples range from 4 to 100 m2/g, depending on the size of the crystal (e.g. massive to 50 nm, respectively), while the big crystals are considered non-porous. In other words, this may provide that the Fe3O4/SiO2@MA has a higher adsorption capacity in removing the contaminants. Moreover, increasing the specific surface area of Fe3O4/SiO2@MA can be due to the presence of silica in Fe3O4/SiO2@MA textural. Meanwhile, the results revealed that the mean pore size of Fe3O4/SiO2@MA was 127 nm. Based on this result and the IUPAC category, the prepared adsorbents Fe3O4/SiO2@MA, can be categorized into mesopores groups.