Emerging iron-based mesoporous materials for adsorptive removal of pollutants: Mechanism, optimization, challenges, and future perspective.

Iron-based materials (IBMs) have shown promise as adsorbents due to their unique physicochemical properties. This review provides an overview of the different types of IBMs, their synthesis methods, and their properties. Results found in the adsorption of emerging contaminants to a wide range of IBMs are discussed. The IBMs used were evaluated in terms of their maximum uptake capacity, with special consideration given to environmental conditions such as contact time, solution pH, initial pollutant concentration, etc. The adsorption mechanisms of pollutants are discussed taking into account the results of kinetic, isotherm, thermodynamic studies, surface complexation modelling (SCM), and available spectroscopic data. A current overview of molecular modeling and simulation studies related to density functional theory (DFT), surface response methodology (RSM), and artificial neural network (ANN) is presented. In addition, the reusability and suitability of IBMs in real wastewater treatment is shown. The review concludes with the strengths and weaknesses of current research and suggests ideas for future research that will improve our ability to remove contaminants from real wastewater streams.

Physicochemical and structural impact of CMC-hydrocolloids on the development of gluten-free foxtail millet biscuits.

Patients with celiac disease and those who are gluten intolerant have a need for gluten-free bakery items but developing them is a challenge for technologists and dietitians. Foxtail millets are naturally gluten-free and nutrient-dense grains. Herein, CMC-modified foxtail millet biscuits (CFMBs) were prepared using 0.01%, 0.05%, and 0.1% of CMC hydrocolloids with foxtail millet flour. The effects of CFMBs on the physicochemical properties, sensory, and morphology were investigated and compared with wheat (WB-100) and foxtail millet (FMB-100) products. CFMBs were thicker, had a larger specific volume, and had a lower diameter and spread ratio than FMB-100. CFMB-0.1 exhibited higher moisture content, higher water activity, and lower fat content than FMB-100 and WB-100. The hardness of CFMB-0.1 (35.08 ± 0.26 N) was close to WB-100 (37.75 ± 0.104 N) but higher than FM-100 (21.61 ± 0.064 N). The scanning electron microscope (SEM) study indicated that incorporating CMC influenced the morphology and microstructure of CFMBs. Skilled panelists gave WB-100 and CFMB-0.1 the highest sensory ratings and FMB-100 the lowest due to their color, appearance, flavor, and overall acceptability. Finally, CMC may be easily included in FMB manufacturing and supported like gluten in the food sector to suit the nutritional demands of customers.

Wrinkled Flower-Like rGO intercalated with Ni(OH)2 and MnO2 as High-Performing Supercapacitor Electrode.

This study reports a simple one-step hydrothermal method for the preparation of a Ni(OH)2 and MnO2 intercalated rGO nanostructure as a potential supercapacitor electrode material. Having highly amorphous rGO layers with turbostratic and integrated wrinkled flower-like morphology, the as-prepared electrode material showed a high specific capacitance of 420 F g-1 and an energy density of 14.58 Wh kg-1 with 0.5 M Na2SO4 as the electrolyte in a symmetric two-electrode. With the successful intercalation of the γ-MnO2 and α-Ni(OH)2 in between the surface of the as-prepared rGO layers, the interlayer distance of the rGO nanosheets expanded to 0.87 nm. The synergistic effect of γ-MnO2, α-Ni(OH)2, and rGO exhibited the satisfying high cyclic stability with a capacitance retention of 82% even after 10 000 cycles. Thus, the as-prepared Ni(OH)2 and MnO2 intercalated rGO ternary hybrid is expected to contribute to the fabrication of a real-time high-performing supercapacitor device.

Boosting capacitive performance of manganese oxide nanorods by decorating with three-dimensional crushed graphene.

This work reports the rational design of MnOx nanorods on 3D crushed reduced graphene oxide (MnOx/C-rGO) by chemical reduction of Ni-incorporated graphene oxide (GO) followed by chemical etching to remove Ni. The resulting MnOx/C-rGO composite synergistically integrates the electronic properties and geometry structure of MnOx and 3D C-rGO. As a result, MnOx/C-rGO shows a significantly higher specific capacitance (Csp) of 863 F g-1 than MnOx/2D graphene sheets (MnOx/S-rGO) (373 F g-1) and MnOx (200 F g-1) at a current density of 0.2 A g-1. Furthermore, when assembled into symmetric supercapacitors, the MnOx/C-rGO-based device delivers a higher Csp (288 F g-1) than MnOx/S-rGO-based device (75 F g-1) at a current density of 0.3 A g-1. The superior capacitive performance of the MnOx/C-rGO-based symmetric device is attributed to the enlarged accessible surface, reduced lamellar stacking of graphene, and improved ionic transport provided by the 3D architecture of MnOx/C-rGO. In addition, the MnOx/C-rGO-based device exhibits an energy density of 23 Wh kg-1 at a power density of 113 Wkg-1, and long-term cycling stability, demonstrating its promising potential for practical application.

Preparation of Manganese Oxide Nanoparticles with Enhanced Capacitive Properties Utilizing Gel Formation Method.

Development of efficient and environmentally benign materials is important to satisfy the increasing demand for energy storage materials. Nanostructured transition-metal oxides are attractive because of their variety in morphology, high conductivity, and high theoretical capacitance. In this work, the nanostructured MnO2 was successfully fabricated using a gel formation process followed by calcination at 400 °C (MNO4) and 700 °C (MNO7) in the presence of air. The suitability of the prepared materials for electrochemical capacitor application was investigated using graphite as an electrode substrate. The chemical, elemental, structural, morphological, and thermal characterizations of the materials were performed with relevant techniques. The structural and morphological analyses revealed to be a body-centered tetragonal crystal lattice with a nano-tablet-like porous surface. The capacitive performances of the MNO4- and MNO7-modified graphite electrodes were examined with cyclic voltammetry and chronopotentiometry in a 0.5 M Na2SO4 aqueous solution. The synthesized MNO7 demonstrated a higher specific capacitance (627.9 F g-1), energy density (31.4 Wh kg-1), and power density (803.5 W kg-1) value as compared to that of MNO4. After 400 cycles, the material MNO7 preserves 100% of capacitance as its initial capacitance. The highly conductive network of nanotablet structure and porous morphologies of MNO7 are most likely responsible for its high capacitive behavior. Such material characteristics deserve a good candidate for electrode material in energy storage applications.