Influence of chitosan addition on resorcinol-formaldehyde xerogel structure

Gels are usually not environment-friendly due to their difficult biodegradability. Therefore, the addition of chitosan, even in small amounts, will make such gels biodegradable and thus can be useful in many applications that require environment-friendly materials. The addition of small quantities of chitosan to the reacting solution resorcinol-formaldehyde xerogel was investigated. Different hybrid resorcinol-formaldehyde-chitosan xerogels were characterized by dierent techniques, including Raman spectra, FTIR, XRD, TGA, SEM, surface area and porosity analyzer, and CHNS/O microanalyzer. It was seen that the addition of chitosan, even in a minor quantity, has a significant influence on the structural features of the resulting xerogels. The lattice order and crystallinity, chemical functions, thermal stability, morphology, elemental ratio, pore structure, and appearance were changed by adding chitosan into the xerogel structure. - 2019 by the authors. Licensee MDPI, Basel, Switzerland.This publication was made possible by the NPRP award (NPRP 08-014-2-003) from the Qatar National Research Fund (a member of Qatar Foundation). Statements made herein are the sole responsibility of the authors. Technical support from the Department of Chemical Engineering, Central Laboratory Unit (CLU) and Gas Processing Centre (GPC) at Qatar University is also acknowledged. Further, the publication of this article was funded by the Qatar National Library.Scopu

REMOVED: High Performance Gas Separation Membrane from a Polymer of Intrinsic Microporosity by Photochemical Surface Modification

This article has been removed: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).This article has been removed at the request of the Executive Publisher.This article has been removed because it was published without the permission of the author(s)

Influence of casting solvents on co2/ch4 separation using polysulfone membranes

Polysulfone membranes exhibit resistance to high temperature with low manufacturing cost and high efficiency in the separation process. The composition of gases is an important step that estimates the efficiency of separation in membranes. As membrane types are currently becoming in demand for CO2/CH4 segregation, polysulfone will be an advantageous alternative to have in further studies. Therefore, research is undertaken in this study to evaluate two solvents: chloroform (CF) and tetrahydrofuran (THF). These solvents are tested for casting polymeric membranes from polysulfone (PSF) to separate every single component from a binary gas mixture of CO2/CH4 . In addition, the effect of gas pressure was conducted from 1 to 10 bar on the behavior of the permeability and selectivity. The results refer to the fact that the maximum permeability of CO2 and CH4 for THF is 62.32 and 2.06 barrer at 1 and 2 bars, respectively. Further, the maximum permeability of CF is 57.59 and 2.12 barrer at 1 and 2 bars, respectively. The outcome selectivity values are 48 and 36 for THF and CF at 1 bar, accordingly. Furthermore, the study declares that with the increase in pressure, the permeability and selectivity values drop for CF and THF. The performance for polysulfone (PSF) membrane that is manufactured with THF is superior to that of CF relative to the Robeson upper bound. Therefore, through the results, it can be deduced that the solvent during in-situ synthesis has a significant influence on the gas separation of a binary mixture of CO2/CH4 .Scopu

Consequence of aging at Au/HTM/perovskite interface in triple cation 3D and 2D/3D hybrid perovskite solar cells

Perovskite solar cells (PSCs) expressed great potentials for offering a feasible alternative to conventional photovoltaic technologies. 2D/3D hybrid PSCs, where a 2D capping layer is used over the 3D film to avoid the instability issues associated with perovskite film, have been reported with improved stabilities and high power conversion efficiencies (PCE). However, the profound analysis of the PSCs with prolonged operational lifetime still needs to be described further. Heading towards efficient and long-life PSCs, in-depth insight into the complicated degradation processes and charge dynamics occurring at PSCs' interfaces is vital. In particular, the Au/HTM/perovskite interface got a substantial consideration due to the quest for better charge transfer; and this interface is debatably the trickiest to explain and analyze. In this study, multiple characterization techniques were put together to understand thoroughly the processes that occur at the Au/HTM/perovskite interface. Inquest analysis using current–voltage (I–V), electric field induced second harmonic generation (EFISHG), and impedance spectroscopy (IS) was performed. These techniques showed that the degradation at the Au/HTM/perovskite interface significantly contribute to the increase of charge accumulation and change in impedance value of the PSCs, hence resulting in efficiency fading. The 3D and 2D/3D hybrid cells, with PCEs of 18.87% and 20.21%, respectively, were used in this study, and the analysis was performed over the aging time of 5000 h. Our findings propose that the Au/HTM/perovskite interface engineering is exclusively essential for attaining a reliable performance of the PSCs and provides a new perspective towards the stability enhancement for the perovskite-based future emerging photovoltaic technology.Scopu

The effect of chitosan's addition to resorcinol/formaldehyde xerogels on the characteristics of resultant activated carbon

Hybrid chitosan-resorcinol/formaldehyde xerogels were synthesized, and the effect of including minor quantities of chitosan on the consequent activated carbon was investigated. The resulting activated carbon were characterized by different techniques. Clear changes were found in the structure of activated carbon as a result of including chitosan in the synthesis. The results showed that the disorder ratio of crystal lattice decreased from 0.750 to 0.628 when increasing the concentration of chitosan from 0 to 0.037 wt%. The micropores increased from ~0.3% to ~1.0%, mesopores increased from ~11.2% to ~32.9% and macropores decreased from ~88.4% to ~66.1%. The total pore volume decreased from 1.040 to 0.238 cm3/g and the total pore surface area decreased from 912.3 to 554.4 m2/g. On the other hand, the average pore width decreased from 2.3 to 0.8 nm and the average particle size decreased from 224 to 149 nm. Nano-scale Scanning Electron Microscope (NanoSEM) morphology indicated a critical composition of chitosan (0.022 wt%) that affects the structure and thermal stability of activated carbon produced. - 2019 by the authors.This publication was made possible by the NPRP award (NPRP 08-014-2-003) from the Qatar National Research Fund (a member of Qatar Foundation). Statements made herein are the sole responsibility of the authors. Technical support from the Department of Chemical Engineering, Central Laboratory Unit (CLU) and Gas Processing Centre (GPC) at Qatar University is also acknowledged. Further, the publication of this article was funded by the Qatar National Library. This research was funded by Qatar National Research Fund (QNRF), Qatar; grant number NPRP 08-014-2-003.Scopu

Effect of gas templating of resorcinol-formaldehyde xerogels on characteristics and performances of subsequent activated carbons

Gas-templated resorcinol formaldehyde-activated carbon xerogels (GT-RF-ACXs) were prepared from resorcinol-formaldehyde xerogels that were templated by infusing different gases (e.g., nitrogen, oxygen, methane, ethylene, ethane, propylene, n-butane, air, propane, helium, argon, carbon dioxide and hydrogen) into the sol media upon its gelation, with subsequent carbonization and activation of the gas-templated xerogels. The crystallinity, adsorption isotherms; pore structure, chemical structure and particle size of GT-RF-ACXs were studied. Wide ranges of characteristics were obtained for GT-RF-ACXs templated with different gases. The effect of templating with different gases on the adsorption performances of GT-RF-ACXs were demonstrated in aqueous media for the removal of (Ni2+, Pb2+ or Cr3+) ions from water; and in gas media for the adsorption of CO2, CH4 and N2. It was found that the gas-templating has a strong effect on the adsorption performance of GT-RF-ACXs towards different species in aqueous or gas media. Therefore, it is evident that gas-infusion during the synthesis of gel precursors significantly affects the features and their separation abilities of their subsequent activated carbons. - 2019 Elsevier B.V.This publication was made possible by the support of the NPRP awards [ NPRP 08-014-2-003 and NPRP-8-001-2-001 ] from the Qatar National Research Fund (a member of The Qatar Foundation). Technical support from the Department of Chemical Engineering and the Central Laboratory Unit at Qatar University is also acknowledged. The statements made herein are solely the responsibility of the authors.Scopu

Gas templating of resorcinol-formaldehyde xerogels

Gas templating of gels is a novel route in the know-how technology of templating porous gels. This technology depends basically on infusing certain gases into the media of sol-gel reaction upon the gelation process. The templated products have noticeable changes that depend on the synthesis conditions and the type of gas used. Furthermore, the gases used for templating are separated completely by natural means; and thus, the templated gels are not polluted with templating agents, which makes them friendlier to the environment. Resorcinol and formaldehyde precursors were used herein as a representative example for making and designing gas-templated resorcinol and formaldehyde-xerogels (GT-RFXs). It is found that different infused gases have noticeable changes on the characteristics and performances of the formed GT-RFXs.This publication was made possible by the support of the NPRP awards [ NPRP 08-014-2-003 and NPRP-8-001-2-001 ] from the Qatar National Research Fund (a member of The Qatar Foundation). Technical support from the Department of Chemical Engineering and the Central Laboratory Unit at Qatar University is also acknowledged. The statements made herein are solely the responsibility of the authors.Scopu

Dataset on the new recipe for the preparation of nanoporous carbon nanorods using resorcinol-formaldehyde xerogels

The data presented in this article are related to the research article entitled “Novel controlled synthesis of nanoporous carbon nanorods from resorcinol-formaldehyde xerogels" (Awadallah-F and Al-Muhtaseb, 2017) [1]. This article describes the novel controlled approach of nanoporous carbon nanorods synthesis from resorcinol/formaldehyde xerogels. The field dataset is made publicly available to enable critical or extended analyzes.This publication was made possible by the support of the NPRP awards [ NPRP 08–014-2–003 and NPRP-08-001-02-001 ] from the Qatar National Research Fund (a member of The Qatar Foundation). The statements made herein are solely the responsibility of the authors. Authors are also thankful to the Department of Chemical Engineering and the Central Laboratory Unit at Qatar University.Scopu

REMOVED: Nanocomposite Membrane of a Polymer of Intrinsic Microporosity and Zeolitic Imidazolate Frameworks for Gas Separation

This article has been removed: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).This article has been removed at the request of the Executive Publisher.This article has been removed because it was published without the permission of the author(s)

Nanocomposite Membranes of Silica and Polysulfone for Improved Gas Permeation

Polysulfone-Silica mixed matrix hybrid membranes have been prepared by incorporating silicon dioxide nanoparticles with average particle size of 136 nm. Two types of polysulfone-silica nanocomposite membranes were prepared by solution casting and solvent evaporation method to study the permeation of CO2 and N2 gases. Barrier properties were investigated as a function of nanoparticle composition for pure gases. SEM testing reveals that such composites have higher bounding with the polymeric matrix. Gas permeation measurements demonstrate that these materials show notable differences in gas separation efficiency, especially for the enrichment of nitrogen (N2) from carbon dioxide (CO2).NPRP Grant from Qatar National Research Fun