Ibuprofen Adsorption onto Olive Pomace Activated Carbon

Posted on by
Ibuprofen Adsorption onto Olive Pomace Activated Carbon

The potential of activated carbon derived from olive pomace in the adsorption of ibuprofen from aqueous solution was explored. The effects of initial concentration and pH of the solution and adsorbent dosage were studied, and the adsorption capacity was evaluated through equilibrium and kinetic adsorption. The study found high adsorption capacity and good batch and fixed-bed adsorption performance.


Abstract

Pharmaceutical compounds present in liquid effluents have great environmental impact. Thus, the development of alternative adsorbent materials from agro-industrial activities has received attention. This work aimed to adsorb ibuprofen onto activated carbon from olive pomace and evaluate the parameters of the adsorption system. The experiments were performed in batch and continuous flow. The mathematical models that best described the experimental data were the pseudo-second-order and Langmuir models for kinetic and isothermal studies. The fixed bed experiments showed a good fit for the Thomas model.

Synthesis and Characterization of 15N‐Labeled Poly(sulfur nitride) in Bulk and in Superconductor Composites

Posted on by
Synthesis and Characterization of 15N-Labeled Poly(sulfur nitride) in Bulk and in Superconductor Composites

S4 15N4 was used for the synthesis of poly(sulfur nitride). The isotope ratio in the labeled polymer was obtained by laser deposition ionization time-of-flight mass spectroscopy. Solid-state 15N nuclear magnetic resonance spectroscopy of S15N x indicates that at least three different chemical environments for 15N atoms are present in the crystals.


Abstract

15N-labeled tetrasulfur tetranitride (S4 15N4) was synthesized by reacting S2Cl2 with 15NH3. The reaction was finalized with 14NH3. The successful labeling was confirmed by solution 15N nuclear magnetic resonance (NMR) spectroscopy. S4 15N4 was used for the synthesis of poly(sulfur nitride) S15N x via the intermediate species of S2N2. It was a topochemical polymerization in the solid state. The isotope ratio in the labeled polymer was obtained by laser deposition ionization time-of-flight mass spectroscopy. Solid-state 15N NMR spectroscopy of S15N x indicates that at least three different chemical environments for 15N atoms are present in the crystals. Finally, SN x was polymerized in the presence of two other superconductors, MgB2 and yttrium barium copper oxide (YBCO), which demonstrates the capability of SN x for grain boundary engineering.

Electron‐Deficient Phenanthrenequinone Derivative for Photoactivated Hydrogen Atom Transfer Mediated Oxidation of Secondary Alcohols

Posted on by
Electron-Deficient Phenanthrenequinone Derivative for Photoactivated Hydrogen Atom Transfer Mediated Oxidation of Secondary Alcohols

We designed a synthetic route for previously unpublished photocatalyst, 3,6-bis(trifluoromethyl)-9,10-phenanthrenequinone (PQ-CF3), and studied its photophysical properties in comparison with other known phenanthrenequinones. The photocatalytic efficacy was demonstrated in the oxidation of 29 secondary alcohols. Mechanistic studies revealed that regardless of the electronic properties of the substrate, PQ-CF3 operates rather via highly efficient hydrogen atom transfer (HAT) than single-electron transfer (SET).


Abstract

In 2000, Fukuzumi and co-workers reported a seminal study on the photochemical oxidation of benzylic alcohols with visible-light-excited 9,10-phenanthrenequinone (PQ) under argon atmosphere (J. Am. Chem. Soc. 2000, 122, 8435). We optimized the reaction conditions they reported and were able to oxidize 1-(4-methoxyphenyl)ethanol quantitatively to 4'-methoxyacetophenone in only 15 min with 10 mol % PQ as a photocatalyst under oxygen. However, we observed a significant decrease in the oxidation rate with more electron-deficient benzylic alcohols as starting materials. To improve the photooxidation performance, we designed a high-yielding synthetic route for a novel, more electron-deficient PQ derivative, 3,6-bis(trifluoromethyl)-9,10-phenanthrenequinone (PQ-CF3). Its efficiency as a photocatalyst in the fast oxidation of secondary alcohols was demonstrated not only with several electronically diverse benzylic alcohols but also with aliphatic substrates. The comprehensive mechanistic studies based on Hammett plot construction, kinetic isotope experiments, and DFT computations suggest that the mechanistic pathway of the alcohol oxidation is dependent on the electronic properties of both the catalyst and the substrate. As the key mechanistic discovery, we showed that the newly developed PQ-CF3 operates as a highly efficient hydrogen atom transfer (HAT) catalyst.

Hydrogen Fuel Cell Technology Revolution and Intervention Using TRIZ S‐curve Analysis for Automotive System Innovation

Posted on by
Hydrogen Fuel Cell Technology Revolution and Intervention Using TRIZ S-curve Analysis for Automotive System Innovation

Renewable energy, carbon neutrality, and global efforts are considered increasingly important. Green hydrogen provides flexibility to power networks and supports intermittent renewable power, benefiting renewable energy grids. Technological progress in ecological hydrogen incremented significantly but its innovation is disruptive. As product diversity expands, the innovation cycle is just beginning.


Abstract

The global energy industrial sector is focused on and committed to supporting clean energy usage and reducing or eliminating the emission of greenhouse gases by 2050. The most preferred technological energy source is the hydrogen-based energy source of the future. This study investigates challenges in the context of technical and non-technical perspectives using one of the tools under the theory of inventive problem solving (TRIZ). The TRIZ tool called S-curve analysis helps assess the technological maturity of the hydrogen fuel cell at four stages: infant, growth, mature and decline, using specific indicators developed by the founder of TRIZ, Genrich Altshuller. The application of TRIZ expands the intervention strategies to successfully accelerate the development of hydrogen fuel cell technology towards the growth stage. Here, an S-curve analysis application will be applied on the hydrogen fuel cell technologies patented in the selected country as a case study in automotive system innovation. The data of patent mapping can support the recommendations presented by TRIZ S-curve analysis, and a proposal of intervention has been delivered to improve the growth of targeted country energy sectors through the strategic initiative of automotive technology evolution and revolution of the hydrogen fuel cell.

Thermodynamic Analysis of Membrane Separation‐Enhanced Co‐Hydrogenation of CO2/CO to Ethanol

Posted on by
Thermodynamic Analysis of Membrane Separation-Enhanced Co-Hydrogenation of CO2/CO to Ethanol

Co-hydrogenation of CO2/CO to produce ethanol presents a notable way to utilize carbon-neutralized biomass resources via gasification, but the highly exothermic reactions lead to a low equilibrium conversion at high temperatures. Applying a water-permselective membrane reactor, water as the byproduct of CO2/CO hydrogenation to ethanol can be removed, enhancing ethanol formation thermodynamically.


Abstract

Co-hydrogenation of CO2/CO to produce ethanol presents an important way to utilize carbon-neutralized biomass resources through gasification. By applying a water-permselective membrane reactor, water, the byproduct of CO2/CO hydrogenation to ethanol, can be removed. Thus, ethanol formation can be promoted thermodynamically. Accordingly, herein, the thermodynamics of ethanol synthesis by CO2, CO, CO2/CO hydrogenation was investigated, as well as the promoting effects of water removal under various temperatures and pressures by Aspen Plus. It is found that, at medium reaction temperature (e.g., 250 °C), medium pressure (e.g., 10–50 bar), and medium CO fraction (e.g., 0.1–0.5) together with 1-stage water removal, a CO2/CO equilibrium conversion higher than 80 % can be obtained.

Freeze‐Thawed Nafion‐Poly(vinyl alcohol) Self‐healing Membranes for Direct Methanol Fuel Cells

Posted on by
Freeze-Thawed Nafion-Poly(vinyl alcohol) Self-healing Membranes for Direct Methanol Fuel Cells

Nafion and poly(vinyl alcohol) (PVA) were used to prepare proton-exchange membranes (PEM) by a physical crosslinking method, freezing-thawing. The Nafion-PVA blend membrane exhibited a self-healing property due to reversible hydrogen bonding, which may increase the PEM's durability. The continued effectiveness of the membrane in preventing methanol after healing is seen as a plus for direct methanol fuel cells.


Abstract

Self-healing proton-exchange membranes (PEMs) made of poly(vinyl alcohol) (PVA) and Nafion were synthesized using the freeze-thaw method. Since PVA is more selective towards water than methanol, the blend membrane successfully reduced methanol permeability and improved selectivity compared to the recast Nafion membrane. The addition of PVA also helped the membrane self-heal by promoting the formation of hydrogen bonds. In contrast to the pristine Nafion, which exhibited even more severe methanol crossover after being damaged than before, the Nafion-PVA membrane underwent a self-healing process and regained much of its methanol barrier function. These advantageous characteristics of the Nafion-PVA membrane suggest its potential use in direct methanol fuel cells (DMFCs).