In this study, the biosorption mechanisms of methylene blue (MB) and Cr(iii) onto pomelo peel collected from our local fruits are investigated by combining experimental analysis with ab initio simulations.
their advantages over other fuel cells in terms of the clean and efficient power generation and lower operating temperature. [1] They are expected to reduce the fossil fuel consumption, which is believed to be the primary sources causing the climate change. PEM, which consists of super acid groups (i.e., sulfonic acid), has been considered as one of the key components in achieving the high fuel cell performance because of its unique fuel cell properties such as ionic conductance, mechanical strength, and thermal and chemical stabilities. When a dry PEM is immersed in water, the hydrophilic chains with sulfonic ion groups can absorb water and consequently form the interconnected ion channels inside the hydrated regions. The macro and microphase separations, viz., crystalline morphologies, conducting layers (ion channels), characteristic domain sizes, and the connection and distribution of the ionic groups and water in the conducting layers and around the crystalline phases are believed to play an important role in the conductivity and mechanical integrity of the PEMs. [2][3][4] Currently, the main challenges to improve the conductivity and mechanical strength of the PEMs are the lack of detailed informationThe changes of the lamellar periods (L 1D ), thickness of lamellar crystals (L c ), and amorphous layers (L a ) within the stacked lamellae of poly(styrenesulfonic acid)-grafted poly(ethylene-co-tetrafluoroethylene) polymer electrolyte membranes (ETFE-PEMs), induced by the preparation and water-absorbing steps are investigated using the small-angle X-ray scattering method. The L 1D values of all the samples quickly increase at a grafting degree (GD) range of less than 19% and then level off. The solvent-induced recrystallization is observed at the early stage of grafting (GD < 10%) and at successive sulfonation and hydration steps. The L 1D , L a , and L c of dry and hydrated PEMs show similar values at higher GD ranges (>34%), leading to the conclusion that most water molecules in the PEMs with higher GDs exist at the outside of the lamellar stacks. Accordingly, for the PEMs with low GD (<19%), all the hydrophilic graft-polymers (ion-channels) locate in the lamellar stacks and are strongly restricted by lamellar crystalline layers, which suppress the swelling of the PEMs. The unique lamellar structures of ETFE-PEMs characterized by L a and L c are well connected with the high conductance and mechanical properties of the membranes, and are suitable for fuel cell applications.
In this study, a novel nanostructure of fluoride red emitting phosphor is synthesized via soft templates. K2SiF6:Mn4+ nanocrystals in the range of 3-5 nm diameter are found inside the porous K2SiF6:Mn4+ nanoparticle hosts, forming unique dots-in-nanoparticles (d-NPs) structures with controlled optical properties. The porous K2SiF6:Mn4+ d-NPs exhibit a sharp and deep red emission with an excellent quantum yield of ∼95.9%, and ultra-high color purity with the corresponding x and y in the CIE chromaticity coordinates are 0.7102 and 0.2870, respectively. Moreover, this nanophosphor possesses good thermal stability in range of 300 K–500 K, under light excitation of 455 nm. The K2SiF6:Mn4+ d-NPs are covered onto a surface of 100×100 µm2 blue-yellow InxGa1−xN nanowire light-emitting diode (LED) to make warm white LEDs (WLEDs). The fabricated WLEDs present an excellent color rendering index of ∼95.4 and a low correlated color temperature of ∼3649 K. Porous K2SiF6:Mn4+ d-NPs are suggested as a potential red component for high color quality micro WLED applications.
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