RSC Advances

Landström, Kritika Narang; Nambi, Ashwin; Kaiser, Andreas; Akhtar, Farid

doi: 10.1039/d3ra01175epmid: 37260714

The synthesis of metal–organic frameworks (MOFs) and their processing into structures with tailored hierarchical porosity is essential for using MOFs in the adsorption-driven gas separation process. We report the synthesis of modified Cu-MOF nanocrystals for CO2 separation from CH4 and N2, prepared from DABCO (1,4-diazabicyclo[2.2.2] octane) and 9,10 anthracene dicarboxylic acid linkers with copper metal salt. The synthesis parameters were optimized to introduce mesoporosity in the microporous Cu-MOF crystals. The volumetric CO2 adsorption capacity of the new hierarchical Cu-MOF was 2.58 mmol g−1 at 293 K and 100 kPa with a low isosteric heat of adsorption of 28 kJ mol−1. The hierarchical Cu-MOF nanocrystals were structured into mechanically stable pellets with a diametral compression strength exceeding 1.2 MPa using polyvinyl alcohol (PVA) as a binder. The CO2 breakthrough curves were measured from a binary CO2–CH4 (45/55 vol%) gas mixture at 293 K and 400 kPa pressure on Cu-MOF pellets to demonstrate the role of hierarchical porosity in mass transfer kinetics during adsorption. The structured hierarchical Cu-MOF pellets showed stable cyclic CO2 adsorption capacity during 5 adsorption–desorption cycles with a CO2 uptake capacity of 3.1 mmol g−1 at 400 kPa and showed a high mass transfer coefficient of 1.8 m s−1 as compared to the benchmark zeolite NaX commercialized binderless granules, suggesting that the introduction of hierarchical porosity in Cu-MOF pellets can effectively reduce the time for CO2 separation cycles.

Khan, Musa; Ali, Faiz; Ramzan, Saba; AlOthman, Zeid A.

doi: 10.1039/d3ra02568cpmid: 37260720

The sophisticatedly altered Hummer's and sol–gel procedures were applied for the synthesis of graphene oxides and porous silica monolith particles respectively. The Fischer esterification protocol was used for coupling silica monoliths with graphene oxides. A N-phenyl acrylamide-incorporated porous polymer was synthesized at the surface of composites via reversible addition fragmentation chain transfer polymerization. The composition was confirmed by Fourier transform infra-red spectroscopy, FE-SEM, X-ray diffraction, zeta potential (zeta pH), Brunauer–Emmett–Teller (BET/BJH) analysis, and EDAX analysis. The resulting polymer-bound composite efficiently removed Cr(VI) and Cr(III) from waste water. Adsorption parameters such as contact time, pH effect, temperature, and adsorbent and adsorbate concentration were optimized for the optimal output of the composite. The kinetic and equilibrium models were applied to the adsorption of Cr(VI) and Cr(III) at the adsorbent surface. The maximum adsorption capacity (qe) of Cr(VI) and Cr(III) was found to be 298.507 mg g−1 and 401.874 mg g−1, respectively, using the same initial concentration of Cr(VI) and Cr(III) [10–60 ppm]. The adsorption data of both states of the Cr-metal followed the pseudo 2nd-order kinetic model with regression values of 0.996 ∼ Cr(VI) and 0.999 ∼ Cr(III) at ambient temperature. Similarly, the adsorption data of Cr(VI) best fit into the Langmuir adsorption isotherm (R2 = 0.972) while that of Cr(III) followed the Freundlich model (R2 = 0.983).

Taheri, Kimiya; Elhamifar, Dawood; Kargar, Shiva; Zarnegaryan, Ali

doi: 10.1039/d3ra01438jpmid: 37260712

Herein, a lamellar structured nano-graphene oxide supported ionic liquid/Fe complex (NGO/IL–Fe) is prepared through grafting of alkyl imidazolium chloride on the NGO followed by treatment with iron(III) chloride hexahydrate. The NGO/IL–Fe nanomaterial was characterized by using FT-IR, PXRD, TGA, EDX and SEM techniques. NGO/IL–Fe was used as a robust and efficient nanocatalyst for the synthesis of tetrahydrobenzo[b]pyrans in water at 25 °C. The desired products were obtained in high yield over a relatively short time. The recoverability, reusability and also leaching tests were performed to study the stability and the nature of the designed catalyst under applied conditions.

Feng, Shouchun; Tan, Jinwang; Ma, Yufan; Chang, Li-Yuan

doi: 10.1039/d3ra02261gpmid: 37260717

In recent years, magnetic nanocatalysts have been recommended as one of the best catalysts by chemists. Among magnetic nanoparticles, Fe3O4 nanoparticles are highly suitable due to their magnetic properties, chemical stability and low toxicity. These catalysts can be separated via magnetic separation after the chemical process is over and reused after regeneration. Owing to the importance of 1,3,5-triazine derivatives in pharmaceutical and medicinal chemistry, the synthesis of these compounds is always one of the important goals of organic chemists. In this research work, we first successfully synthesized CuBr2 immobilized on magnetic Fe3O4 nanoparticles functionalized with Dop-OH (prepared via the reaction of MNP-dopamine with 2-phenyloxirane) nanocomposites and then investigated their catalytic application in the synthesis of 1,3,5-triazine derivatives via an oxidative coupling reaction of amidine hydrochlorides and alcohols in air. Recycling experiments clearly revealed that MNP-[Dop-OH]-CuBr2 nanocatalysts could be reused for at least 8 times without much loss of catalytic activity.

Flores-Reyes, Julio C.; Cotlame-Salinas, Vanesa del C.; Ibarra, Ilich A.; González-Zamora, Eduardo; Islas-Jácome, Alejandro

doi: 10.1039/d3ra02746epmid: 37260715

Classical multicomponent reactions (MCRs) are domino-type one-pot processes in which three or more different reactants are combined sequentially in the same reactor to synthesize compounds containing all or almost all atoms coming from the reactants. Besides, pseudo-MCRs are also domino-type one-pot processes involving combinations of at least three reactants but in which at least one of them takes part in two or more reaction steps. In consequence, the products synthesized through pseudo-MCRs contain also all or almost all atoms but coming from two or more identical reactants. Thus, pseudo-MCRs differ from classical MCRs because the first ones appear to involve an assembly of a higher number of different components than those that are being truly assembled. However, pseudo-MCRs are also useful synthetic tools to generate libraries of complex compounds in few experimental steps, and although the repeated reactants may make them appear less diverse than classical MCRs, this can be offset by the higher number of reactants that can participate in this type of reaction. Overall, there are two types of pseudo-MCRs. The first are those in which the duplicated reagents participate in different steps of the corresponding reaction mechanism. The second kind of pseudo-MCRs are those in which one or more components react simultaneously with a main reagent containing two or more identical functional groups. These latter are known as repetitive pseudo-MCRs. Thus, the aim of the present review is to cover for the first time selected works mainly published in the last two decades about pseudo-MCRs and their repetitive versions toward the synthesis of novel, complex, and highly symmetrical molecules, often including their interesting applications in various fields of science and technology. The manuscript has been categorized considering the number of reagents participating in the corresponding pseudo-MCRs, aiming to give readers novel insights for their future investigations.

Zheng, Jili; Li, Jun; Zhang, Liang; Yang, Yang

doi: 10.1039/d3ra01463kpmid: 37260716

The rapid development of human society has resulted in the extensive release of waste heat. The thermo-electrochemical cell (TEC), a cutting-edge technology that converts low-grade waste heat into electricity, has garnered increasing attention. However, the complex interactions among various processes, such as fluid flow, electrochemical reactions and heat transfer, make it challenging to evaluate their effect on the overall performance of the TEC. Understanding the synergistic mechanisms and coupling effects of these processes is crucial for optimizing and implementing TECs in practical applications. In this paper, a mathematical model is developed by coupling electrochemical reactions and heat/mass transfer. The distributions of ion concentration, electrolyte velocity and temperature are analyzed under varying temperature differences and electrode distances. The results demonstrate a significant interaction between heat transfer and electrolyte flow. Higher temperatures not only improve the open circuit voltage, but also promote ion transport convection and hence enhance the current density. In addition, a higher concentration of ions or smaller electrode spacing exhibits an apparently improved performance of the TEC, due to the facilitated ion transport and reduced concentration overpotential. Notably, electrode spacing has a negligible effect on the maximum power density of the TEC under a constant heat flux, but it does enhance the current density due to the combined effect of heat and ion transfer. Overall, the proposed mathematical model provides deeper insight into the physical–chemical processes involved in TECs and offers valuable guidance for TEC design and practical applications.

Thu, Myo Myo; Chaiammart, Nattapat; Jongprateep, Oratai; Techapiesancharoenkij, Ratchatee; Thant, Aye Aye; Saito, Nagahiro; Panomsuwan, Gasidit

doi: 10.1039/d3ra02314apmid: 37305444

Carbon materials synthesized via a solution plasma process (SPP) have recently shown great potential for various applications. However, they mainly possess a meso–macroporous structure with a lack of micropores, which limits their applications for supercapacitors. Herein, carbon nanoparticles (CNPs) were synthesized from benzene via SPP and then subjected to thermal treatment at different temperatures (400, 600, 800, and 1000 °C) in an argon environment. The CNPs exhibited an amorphous phase and were more graphitized at high treatment temperatures. A small content of tungsten carbide particles was also observed, which were encapsulated in CNPs. An increase in treatment temperature led to an increase in the specific surface area of CNPs from 184 to 260 m2 g−1 through the development of micropores, while their meso–macropore structure remained unchanged. The oxygen content of CNPs decreased from 14.72 to 1.20 atom% as the treatment temperature increased due to the degradation of oxygen functionality. The charge storage properties of CNPs were evaluated for supercapacitor applications by electrochemical measurements using a three-electrode system in 1 M H2SO4 electrolyte. The CNPs treated at low temperatures exhibited an electric double layer and pseudocapacitive behavior due to the presence of quinone groups on the carbon surface. With increasing treatment temperature, the electric double layer behavior became more dominant, while pseudocapacitive behavior was suppressed due to the quinone degradation. Regarding cycling stability, the CNPs treated at high temperatures (with a lack of oxygen functionality) were more stable than those treated at low temperatures. This work highlights a way of introducing micropores into CNPs derived from SPP via thermal treatment, which could be helpful for controlling and adjusting their pore structure for supercapacitor applications.

Guo, Yuxin; Wang, Qiuwen; Liu, Siyu; Ya, Wen; Qi, Ping; Ni, Zenan; Liu, Huimin; Zhang, Qijian

doi: 10.1039/d3ra02046kpmid: 37260719

Long afterglow luminescent (LAL) materials can release their stored light after turning off the light irradiating on them. Because of this unique characteristic, the coupling of LAL materials and conventional semiconductors is an environmental-friendly method for supporting photocatalytic activity for environmental remediation. Currently, the exploration of “afterglow-catalysis” materials for the fabrication of around-the-clock photocatalytic systems is still in its infancy. Accordingly, herein, we summarize the application of LAL materials in photocatalytic environmental remediation and energy crisis alleviation to stimulate further motivation for the development of novel LAL materials. By discussing the works in the last five years on novel LAL materials, we anticipate the development of new materials, i.e., “afterglow-catalysis” composites, to realize waste-to-energy, even achieving industrialization.

Almawgani, Abdulkarem H. M.; Awasthi, Suneet Kumar; Mehaney, Ahmed; Ali, Ghassan Ahmed; Elsayed, Hussein A.; Sayed, Hassan; Ahmed, Ashour M.

doi: 10.1039/d3ra01984epmid: 37260718

In this study, the biosensing capabilities of conventional and hybrid multilayer structures were theoretically examined based on surface plasmon resonance (SPR). The transfer matrix method is adopted to obtain the reflectance spectra of the hybrid multilayer structure in the visible region. In this regard, the considered SPR sensor is configured as, [prism (CaF2)/Al2O3/Ag/Al2O3/2D material/Al2O3/Sensing medium]. Interestingly, many optimization steps were conducted to obtain the highest sensitivity of the new SPR biosensor from the hybrid structure. Firstly, the thickness of an Al2O3 layer with a 2D material (Blue P/WS2) is optimized to obtain an upgraded sensitivity of 360° RIU−1. Secondly, the method to find the most appropriate 2D material for the proposed design is investigated to obtain an ultra-high sensitivity. Meanwhile, the inclusion of black phosphorus (BP) increases the sensor's sensitivity to 466° RIU−1. Thus, black phosphorus (BP) was obtained as the most suitable 2D material for the proposed design. In this regard, the proposed hybrid SPR biosensing design may pave the way for further opportunities for the development of various SPR sensors to be utilized in chemical and biomedical engineering fields.

Zhang, Jingnan; Huang, Hai; Zhang, Ming; Wang, Wenchang

doi: 10.1039/d2ra06762epmid: 37260713

Nanofluids have been recently proposed as new chemical agents for enhanced oil recovery. In this study, in order to reflect the effect of nanofluids on imbibition, the imbibition performance of manganese chloride (MnCl2) solution, sodium dodecylbenzene sulfonate (SDBS) solution, and silica (SiO2) nanofluids were studied by a spontaneous imbibition experiment at 25 °C and 0 MPa. The oil production from pores with different sizes and the imbibition efficiency were tested by nuclear magnetic resonance T2 spectroscopy and metering in spontaneous imbibition. In addition, the interfacial tensions between the imbibition liquids and oil were tested. The changes in the contact angle of the core slice before and after immersing in imbibition liquids were measured. The silica nanofluid is used as the imbibition liquid, and the shift of the T2 spectral peak to the left is not obvious and shifted by only 23.95–25.72 ms, the change in the contact angle is 6.63°–12°, the interfacial tension between the nanofluid and the simulated oil is 0.25–0.41 mN m−1, and the imbibition efficiency was slightly improved with increasing nanoparticle concentration, up to 57.40%, which improved by 16.14% and 32.95%, respectively, compared to the surfactant solution and the manganese chloride solution. This shows that the silica nanofluid can effectively improve oil production in small pores, reduce oil–water interfacial tension, and change rock wettability.