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Recent Advances in Anion Exchange Membranes for Fuel Cell Applications
Published in Anandhan Srinivasan, Selvakumar Murugesan, Arunjunai Raj Mahendran, Progress in Polymer Research for Biomedical, Energy and Specialty Applications, 2023
Vijayalekshmi Vijayakumar, Sang Yong Nam
The presence of the π conjugated structure in imidazolium cation and steric hindrance make it exhibit high stability. Guanidimidazole, a modified version of imidazole as quaternising as well as cross-linking agent was also reported to improve the alkaline stability of the membranes [77]. Lai et al. reported a copolymer of 1-vinyl imidazole and N-vinyl carbazole quaternised with imidazolium cation exhibited high ion conductivity and desirable methanol permeability for AEMFCs. Furthermore, the membrane maintained ion conductivity and IEC of about 79% and 81%, respectively, without further loss up to 1,400 h of exposure in 1 M KOH solution at 60°C. Carbazole, a nitrogen-containing aromatic heterocyclic compound having a large π-conjugated system with rigid fused rings favored the membranes to facilitate excellent thermal and alkaline stability [78]. Ari and his coworkers showed that the incorporation of electron-withdrawing nitro group in quaternized PPO can weaken the interaction between OH− group and quaternary ammonium group in the membrane structure and made the quaternized group less prone to degradation through nucleophilic substitution (SN2) [79]. A facile synthetic strategy developed by Mandal et al. to prepare a series of tetra block AEM copolymers based on vinyl addition polymerization of norborene (alternate two blocks each of butyl norborene and bromopropyl norborene) expressed high thermal stability up to 400°C and ionic conductivity of 122.7 mS cm−1 at 80°C with an IEC of 1.88 meq g−1. The prepared membrane displayed exceptional long-term chemical stability in 1 M NaOH solution at 80°C with no noticeable degradation (< 1%) over a 1,200 h and an excellent fuel cell performance with an optimum power density of 542.57 mW cm−2 at 0.43 V and 1.26 A cm−2 [70].
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Published in Joseph C. Salamone, Polymeric Materials Encyclopedia, 2020
The fundamental raw material for the manufacture of this polymer is carbazole, which present in coal tar in an amount of about 1.5%. It is obtained as a byproduct in the manufacture of anthracene. Carbazole is used in the manufacture of products for the dye industry and, after having been vinylated to N-vinylcarbazole, in the polymerization process to poly(N-vinylcarbazole).
Equilibrium adsorption modelling of selected crude oil components following a spill on Niger Delta soil
Published in Chemistry and Ecology, 2021
Nnamdi David Menkiti, Chukwuemeka Isanbor, Olusegun Ayejuyo
Lee and Kim [25] partitioned naphthalene onto the surface of kaolinite and halloysite by the surfactant HDTMA. They obtained a linear adsorption process that could be described by a dependent on the arrangement of the surfactant cations distribution process. Bastani et al. [26] calcined diatomite to the improved surface area with increased sorption capacity. Functionalised modification using surfactants changes the character of mineral materials such as organoclays [27], activated carbon and bentonite [28] and Zeolites [29,30] surfaces from hydrophilic to hydrophobic, which usually increases the affinity of the sorbent for organic pollutants. This modification is expensive and presents toxicity-related problems because of the quaternary ammonium salts [31]. The goal was to understand the mechanism of interaction of contaminants or crude oil components with natural soil in the Niger Delta region. For instance, the organic carbon content in soil determines the degree of sorption of non-polar organic compounds in soil [32,33], while non-ionisable nitrogen, sulphur and oxygen compounds (NSOs) such as benzothiophene, non-specific interaction (namely van der Waals forces) appear to be dominant in the sorption to clay till [34]. Also, compounds such as pyridine, pyrrole carbazole, indole, benzene and thiophene show a certain polarity which indicates an additional interaction may be playing an important role. Since crude oil is a mixture of complex compounds, this study aims at determining the mechanism of the sorption of crude oil onto the soil in the Niger Delta region through the use of environmentally important constituent of crude oil (phenol, pyridine and phenanthrene) to elucidate the sorption mechanism.
A novel self-assembly based on double-layer zinc porphyrin sensitizers in supramolecular solar cell
Published in Journal of Coordination Chemistry, 2019
Yu Wu, Hua Liu, Jia-Cheng Liu, Ren-Zhi Li, Neng-Zhi Jin
Aromatic amine derivatives are electron-rich compounds and are widely used in optoelectronics [19]. Researchers commonly used arylamine derivatives as donors of photosensitizers in dye-sensitized solar cells [20]. Common electron donors are triphenylamine, triarylamine, indole, phenothiazine, and carbazole. Carbazole and phenothiazine groups with strong photoelectric properties are good donors. In this article, two kinds of electron donors are used as the axis coordination porphyrin and the anchoring porphyrin to construct a supramolecular dye-sensitized solar cell.
Separation of heterocyclic nitrogen compounds from coal tar fractions via ionic liquids: COSMO-SAC screening and experimental study
Published in Chemical Engineering Communications, 2019
Dongmei Xu, Mi Zhang, Jun Gao, Lianzheng Zhang, Shixue Zhou, Yinglong Wang
The single factor experiments were adopted to study the influence of the extraction temperature. Considering the screened ILs are in liquid form at room temperature, 20, 25, 35, 45, and 55, five points were evaluated with the conditions of mass ratio of 1:5 for 30 min. Then, the calculated EE and D values are listed in Figure 7(a), which indicated that the EE and D values of indole and carbazole were little affected by temperature. As the temperature increases, the EE and D values decrease lightly, but the decrease is limited. And this is significantly different from [Bmim][Cl] which exists in a solid state at room temperature. For the neutral N-compounds, the maximum EE and D values of [Bmim][OTf] were 84.32, 64.86 and 10.74, 6.75 at 20, and for [Bmim][Tos] they were 93.68, 73.56 and 29.65, 26.43 at 20. Because of the screened ILs are all in liquid form at room temperature, there is no phase transition during the extraction process to improve the separation efficiency. While with the increase in temperature, the N-compounds are more and more easily soluble in the solvent which reduced the removal efficiency of N-compounds. The EE and D values are less changed due to the selected experimental conditions. In addition, because of the complex structure of carbazole which has a greater steric hindrance than indole, the separation of carbazole by the screened ILs is generally worse than that of indole. This resulting in the decrease in the EE and D values. Thus, the temperature of the extraction process was set at room temperature for the following experiments. In addition, the extraction ability for [Bmim][Tos] and [Bmim][OTf] is in accordance with the calculation results.