Mesoporous Magnesium Oxide Research Articles

Application of ultrasound-assisted technique for production of mesoporous magnesium oxide from solid waste of ductile iron: An alternative method for elimination of surfactants from precipitation process

In the present work, the mesoporous magnesium oxide nanoparticles were produced from the solid waste of ductile iron casting industry. Mg2+ ions were extracted from the waste through the acid leaching, and MgO nanoparticles were obtained by the conventional, and ultrasound-assisted methods. Mg(OH)2 nanoparticles was precipitated in the presence of sodium dodecyl sulfate/Triton, 1:1, and under ultrasound irradiation in the absence of mentioned surfactant. The precipitates were then converted to mesoporous MgO via the calcination at 500 °C. The structure of products was evaluated by X-ray diffractometry (XRD), field emission electron microscopy (FESEM), and N2 adsorption-desorption isotherms. Although MgO nanoparticles with the specific surface area of 118 m2 g−1 could be fabricated by the conventional precipitation, the surfactant concentration should be fixed at the level of 1.5 g L−1. The precipitation under ultrasound irradiation is suggested for the clean fabrication of highly porous powder, 0.7586 cm3 g−1, in which the pore diameter is distributed in the range of 2–12 nm. In consequence, the solid waste of ductile iron industry is a potential material for the fabrication of mesoporous MgO by ultrasound- assisted technique in the absence of surfactant.

Bimetallic AuNi nanoparticles supported on mesoporous MgO as catalyst for Sonogashira-Hagihara cross-coupling reaction

Gold catalysts have been reported to be applied only for the Sonogashira-Hagihara reaction of iodobenzene and phenylacetylene under harsh reaction conditions, while the scope of the reaction has not been expanded for coupling reaction of other aryl halides and alkynes. In this investigation, a cost-effective, Pd-free catalyst based on mesoporous magnesium oxide supported bimetallic AuNi nanoparticles (m-MgO@AuNi) have been synthesized by hydrothermal method and its efficiency has been demonstrated in Sonogashira-Hagihara cross-coupling reaction. The m-MgO@AuNi nanocatalyst was structurally and morphologically characterized using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS) and the mesoporous structure of MgO has been confirmed through BET analysis. Using this palladium-free catalyst, Sonogashira-Hagihara coupling reaction of aryl iodides and aryl bromides with alkynes have been successfully performed and catalyst was recycled for several times. The results demonstrate that the synergistic effect between Au, Ni and mesoporous MgO support plays key role in enhancement of m-MgO@AuNi catalytic activity in Sonogashira-Hagihara reaction.

Model-driven development of durable and scalable thermal energy storage materials for buildings

The energy impact of integrating phase change materials (PCMs) in buildings for thermal energy storage has been modeled by various whole-building simulation programs, demonstrating that PCM incorporation can reduce energy consumption, provide grid flexibility and resilience, and reduce CO2 emissions. The models assume that the PCMs are in perfect operating condition and underestimate the impact of actual phase change behavior (e.g., enthalpy curve shape) on thermal load shifting in practical deployment. In this paper, we bridge the gap between theory and practice when evaluating the energy impact of PCMs by using a model-driven approach to develop durable thermal energy storage materials with desired phase change properties. For ease of integration, we fabricate shape-stabilized PCMs (ss-PCMs) by encapsulating solid-liquid polyethylene glycol (PEG) consisting of different molecular weights within mesoporous magnesium oxide (MgO) matrices. Learning from the modeling results, we manipulate phase change properties such as peak melting temperature and temperature glide of PEG-MgO ss-PCMs during the synthesis process to achieve desired properties. As such, the energy density is maximized within the optimum operating temperature range, which is critical to boosting energy efficiency. Compared to a case with no PCM, a layer of PEG-MgO ss-PCM integrated into the wall provides a 50% reduction in the peak load and also exhibits a repeatable phase change behavior for up to 1000 thermal cycles without leakage, showing durability of this material. We also show that this lab-scale synthesis process is easy to be scaled up by 100 times for a demonstration of large-scale industrial production. The synthetic tunability of transition temperature of ss-PCMs also extends their applicability beyond buildings.

Mesoporous Magnesium Oxide Adsorbent Prepared via Lime (Citrus aurantifolia) Peel Bio-templating for CO2 Capture

The utilization of the lime (Citrus aurantifolia) peel as a template can improve the adsorbent’s structural properties, which consequently affect its CO2 uptake capacity. Herein, a mesoporous magnesium oxide (MgO-lime (Citrus aurantifolia) peel template (LPT)) adsorbent was synthesized using an LPT. MgO-LPT demonstrated improved structural properties and excellent CO2 uptake capacity. Moreover, another MgO adsorbent was prepared via thermal decomposition (MgO-TD) for comparison. The prepared adsorbents were characterized by N2 physisorption, Fourier transform infrared spectroscopy and thermogravimetric analysis. The CO2 uptake of these adsorbents was under 100% CO2 gas and ambient temperature and pressure conditions. MgO-LPT exhibited a higher Brunauer–Emmett–Teller surface area, Barrett–Joyner–Halenda pore volume, and pore diameter of 23 m2.g−1, 0.142 cm3.g−1, and 24.6 nm, respectively, than those of MgO-TD, which indicated the mesoporous structure of MgO-LPT. The CO2 uptake capacity of MgO-LPT is 3.79 mmol CO2.g−1, which is 15 times that of MgO-TD. This study shows that the application of lime peel as a template for the synthesis of MgO adsorbents is a promising approach to achieve MgO adsorbents with enhanced surface area and thus increased CO2 capture performance. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

High-performance flake-like mesoporous magnesium oxide prepared by eggshell membrane template for carbon dioxide capture

The utilization of eggshell membrane (ESM) as a template can improve the structural properties of the synthesised adsorbent, further affecting its CO2 uptake capacity. In this study, a flake-like shape mesoporous magnesium oxide (MgO) adsorbent was synthesised via the ESM bio-templating method to form MgO-BT. The prepared adsorbents were characterised by field emission scanning electron microscopy equipped with an energy-dispersive X-ray (FESEM-EDX), X-ray diffraction (XRD), N2 physisorption, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and CO2-temperature programmed desorption (CO2-TPD). The flake-like shape MgO-BT possesses an improved surface area of 79 m2/g, which is higher than the MgO adsorbent prepared by the thermal decomposition method (MgO-TD). Also, ESM bio-templating method has resulted in the increase of MgO-BT's basic site which mainly composed of strong-basic attachment site. These improved MgO-BT's structural properties have led to the increased CO2 uptake capacity of 1.55 ​mmol/g, which is 6-times higher than MgO-TD (0.23 ​mmol/g) at ambient temperature and pressure under 100% CO2 flow condition. Moreover, under flue gas conditions, the MgO-BT has demonstrated a slight reduction in CO2 uptake (~15%), however, this value is still tremendously higher than MgO-TD. It can be concluded that the utilization of ESM as a bio-template in the MgO preparation stage has significantly influenced the physicochemical properties of the adsorbent, therefore leading to a high CO2 adsorption performance.

Facile synthesis of mesoporous magnesium oxide–graphene oxide composite for efficient and highly selective adsorption of hazardous anionic dyes

Mesoporous magnesium oxide–graphene oxide composite (MGC) has been synthesized using a facile post-immobilization method by mixing pre-synthesized magnesium oxide (MgO) with graphene oxide (GO). MgO used for fabrication of the composite has been synthesized using an environment-friendly method involving gelatin as a template. XRD, Raman and EDX analyses have confirmed the presence of MgO and GO in the composite. FTIR and SEM analyses of synthesized MGC have further elucidated the surface functionalities and morphology, respectively. Using N2 adsorption–desorption isotherm, BET surface area of MGC has been calculated to be 55.9 m2 g−1 and BJH analysis confirmed the mesoporous nature of MGC. The application of synthesized MGC as a selective adsorbent for various toxic anionic dyes has been explored. Batch adsorption studies have been carried out to investigate the influence of different adsorption parameters on the adsorption of two anionic dyes: indigo carmine (IC) and orange G (OG). The maximum adsorption capacities exhibited by MGC for IC and OG are 252.4 and 24.5 mg g−1, respectively. Plausible mechanism of dye adsorption has been explained in detail using FTIR analysis. In a mixture of cationic and anionic dyes, MGC selectively adsorbs anionic dyes with high separation factors, while in binary mixtures of anionic dyes, both dyes are adsorbed efficiently. Thus, MGC has been shown to be a potential adsorbent for the selective removal of anionic dyes from wastewater.

Wormhole-like mesoporous magnesium oxide fabricated by surfactant templating method to enhance cycling performance of lithium-sulfur batteries

Lithium-sulfur (Li–S) batteries are considered to have the best development prospect for electric vehicles. But enhancing the cycling performance of Li–S batteries is necessary and urgent. Mesoporous MgO particles (MMgO) are prepared by surfactant templating method and used to prepare cathode materials for the first time. The prepared MMgO has a hexagonal flake-like structure with a thickness of 50–80 nm, a transverse length of 150–350 nm, a processing area of 181.56 m2/g, an average pore diameter of 3.11 nm and a pore volume of 0.26 cc/g. MMgO shows low intensity and slightly broader diffraction peaks in the XRD pattern, indicating the presence of lattice distortion, defects, dislocations or unsaturated valence bonds. MMgO particles are uniformly distributed on the sulfur surface to provide high surface area, many active sites and interconnected channel structure, which makes more sulfur contact with MMgO to be adsorbed, activated and participated in charge and discharge reaction. The Li–S battery containing sulfur/MMgO composite at weight ratio 90:10 shows the best cyclic stability with capacity retention rate 84.7% after 100 cycles at 0.2 C. The initial specific capacity of a Li–S battery with sulfur/MMgO composite at weight ratio 70:30 can reach 1062 mAh/g at 0.2 C, which is much higher than sulfur/commercial MgO at the same weight ratio.

Synthesis, characterization and low-temperature carbonation of mesoporous magnesium oxide

A sample of MgO was successfully synthesized using thermal decomposition of hydromagnesite and compared to commercial material. The characterization of materials using XRD, SEM, BET and BJH methods showed that the thermal decomposition way led to rectangular mesoporous microsheets with high specific surface area of 100 m2 g−1. This porous magnesium oxide has been shown to be a potential candidate for CO2 capture at low temperatures range (30 and 50 °C), low pressures of CO2 ( $$ P_{{{\text{CO}}_{2} }} = 600\;{\text{mbar}} $$ ) and in the presence of water vapor ( $$ P_{{{\text{H}}_{2} {\text{O}}}} = 15\;{\text{mbar}} $$ ). In these conditions, our results show that 11% of MgO was converted to hydrated magnesium carbonate MgCO3·3H2O after 8 h of carbonation in a thermobalance and reached 54% after 24 h of carbonation using tube furnace. After carbonation, hydration reaction pore size and surface area have noticeably changed.

Mesoporous Magnesium Oxide Nanosheet Electrocatalysts for the Detection of Lead(II)

Ultrathin two-dimensional (2D) magnesium oxide nanosheets (MgO-NSs) with mesoporous structure (Brunauer–Emmett–Teller surface area of 158 m2·g–1 and a pore size of 2–3 nm) are proposed as excellent electrocatalysts for the detection of lead(II). A sugar-blowing-induced confined synthesis method was developed to synthesize MgO-NSs by one-step calcination of a Mg(NO3)2–glucose mixture. Impressively, MgOs-NSs display excellent sensing performances for the electrochemical detection of lead(II) with a detection limit of 0.16 nM and a linear range of 20–150 nM (R2 = 0.996). This work sheds light on the preparation of ultrathin 2D mesoporous nanosheets for sensing applications.

Graphene-induced hierarchical mesoporous MgO for the Claisen–Schmidt condensation reaction

Multistage mesoporous magnesium oxide prepared by a simple hydrothermal method has an ideal particle size, channel distribution, active crystal face, good catalytic activity and regeneration ability.

High tribology performance of Poly(vinylidene fluoride) composites based on three-dimensional mesoporous magnesium oxide nanosheets

Three-dimensional mesoporous MgO nanosheets (MgO_NS) were synthesized by a facile non-hydrothermal method for the improvement of the tribological properties of poly(vinylidene fluoride) (PVDF) composites. The interactions and structural properties of the MgO_NS composites were systematically compared with those of commercially available MgO beads (MgO_B). It was found that the incorporation of MgO_NS decreased the polar β phase of the PVDF crystallinity owing to an intimate contact and good interactions between the mesoporous MgO_NS filler and PVDF matrix. Recipro-mode tribology tester results for a long measurement time of 3 h showed that the friction coefficients of the PVDF composites decreased with the increasing filler content for both MgO_B and MgO_NS, indicating an important role of MgO as a self-lubricating material. In particular, the PVDF/MgO_NS 5.0% composite exhibited an outstanding initial friction coefficient of 0.091 and specific wear rate of 1.8 × 10−5 mm3/N m as compared with MgO_B, this performance being among the best for PVDF-based composites. The results indicated that mesoporous MgO_NS composites with their small crystal size, large surface area, good dispersion, and intimate contact with the PVDF matrix were more effective than randomly organized MgO_B.

EFFECT OF PREPARATION METHOD ON PHYSICOCHEMICAL PROPERTIES OF NANOSTRUCTURED MgO POWDER

Magnesium oxide is widely used as an adsorbent, catalyst, identifier of chemical and toxic pollutants, in water and gas purification processes. Mesoporous magnesium oxide powder has been synthesized by the method of deposition, spray pyrolysis and glycine-citrate-nitrate method, their crystal structure, microstructure, granulometric composition and adsorption properties have been studied. Optimal conditions for the production of magnesium oxide by the glycine-citrate-nitrate method have been determined, which make it possible to obtain a powder with average primary particle sizes of 12 nm and the smallest sizes of secondary particles starting from 70 nm. The influence of the method of obtaining nanostructured magnesium oxide powder on the physicochemical properties is established. High values of the total pore volume of 1.038 cm3 /g exhibited the MgO powder obtained by the precipitation method.

A Novel Method to Improve the Anticancer Activity of Natural-Based Hydroxyapatite against the Liver Cancer Cell Line HepG2 Using Mesoporous Magnesia as a Micro-Carrier.

Micro-carriers are the best known vehicles to transport different kinds of drugs to achieve high impact. In this study, mesoporous magnesium oxide has been harnessed as a micro-carrier to encapsulate the anticancer candidate drug natural-based cubic hydroxyapatite (HAP). HAP@MgO composites with different HAP loading (0–60 wt %), were prepared by a hydrothermal treatment method using triethanol amine as a template. The characterization of the prepared composites were achieved by using XRD, Raman spectroscopy, FTIR and SEM. Characterization data confirm the formation of sphere-like structures of MgO containing HAP particles. It was observed that the size of the spheres increased with HAP loading up to 40 wt %, then collapsed. Furthermore, the anticancer property of the prepared composites was evaluated against the HepG2 liver cancer cell line. The HAP@MgO composites exhibited higher activity than neat MgO or HAP. The 20 wt % of HAP was the optimum loading to control cell proliferation by inducing apoptosis. Apoptosis was determined by typical apoptotic bodies produced by the cell membrane.

Organic Polymers as Porogenic Structure Matrices for Mesoporous Alumina and Magnesia

Mesoporous alumina and magnesia were prepared using various polymers, poly(ethylene glycol) (PEG), poly(vinyl alcohol) (PVA), poly(N-(2-hydroxypropyl) methacrylamide) (PHPMA), and poly(dimethylacrylamide) (PDMAAm), as porogenic structure matrices. Mesoporous alumina exhibits large Brunauer–Emmett–Teller (BET) surface areas up to 365 m2 g−1, while mesoporous magnesium oxide possesses BET surface areas around 111 m2 g−1. Variation of the polymers has little impact on the structural properties of the products. The calcination of the polymer/metal oxide composite materials benefits from the fact that the polymer decomposition is catalyzed by the freshly formed metal oxide.

Fabrication of mesoporous magnesium oxide nanosheets using magnesium powder and their excellent adsorption of Ni (II)

Mesoporous MgO nanosheets with a high adsorption rate and excellent adsorption capacity for removing Ni (II) were successfully synthesized by a hydrothermal and annealing method. The Mg(OH)2 was first synthesized by a hydrothermal process using magnesium powder as the starting material. MgO was then obtained by annealing the as-prepared Mg(OH)2 at 450°C. The advantage of the magnesium powder as the starting material is it slowly generated Mg2+. Thus, the low centration of Mg2+ guaranteed a slow rate of forming Mg(OH)2, which benefited with a mesoporous structure. The effect of the hydrothermal time on the structure and adsorption performance was studied. The results showed that the MgO synthesized for 4h had the highest adsorption performance of 2217mg/g and the highest adsorption rate, which resulted in an efficient adsorption of 96% in 5min for Ni (II) with the concentration of 500mg/L.

Sorption capacity and stability of mesoporous magnesium oxide in post-combustion CO2 capture

Mesoporous magnesium oxides with a high surface area (672–686 m2/g) were synthesized by an aerogel method and subsequently evaluated for CO2 capture efficiency under ambient-temperature sorption and intermediate-temperature regeneration. The effects of one-step (MgO-1) and four-step (MgO-4) calcination methods on the as-prepared MgO samples were evaluated with respect to textual properties and CO2 sorption capacity at various temperatures (30–350 °C). The as-prepared MgOs showed greater than 10 wt% of CO2 sorption at 30 °C, showing very fast sorption of more than 7 wt% CO2 within 5 min. The cyclic stability of the sorbents was tested by using CO2 sorption at 30 °C and N2 regeneration at 450 °C. The sorption performance of MgO-1 was more stable and higher than that of MgO-4, but the surface area and pore volume were still reduced. The cyclic sorption capacity became 6.1 wt% at the condition of mixture gas sorption (CO2/N2: 15/85 vol%) and CO2 regeneration. Since inter-crystallites coupling plays an important role in pore formation as well as stability, calcination condition can contribute to preventing the degradation level of performance and textural properties of sorbents.

Hydrothermal Fabrication of High Specific Surface Area Mesoporous MgO with Excellent CO2 Adsorption Potential at Intermediate Temperatures

In this work, we report on a novel sodium dodecyl sulfate (SDS)-assisted magnesium oxide (MgO)-based porous adsorbent synthesized by hydrothermal method for intermediate CO2 capture. For industrial MgO, its CO2 adsorption capacity is normally less than 0.06 mmol g−1, with a specific surface area as low as 25.1 m2 g−1. Herein, leaf-like MgO nanosheets which exhibited a disordered layer structure were fabricated by the introduction of SDS surfactants and the control of other synthesis parameters. This leaf-like MgO adsorbent showed an excellent CO2 capacity of 0.96 mmol g−1 at moderate temperatures (~300 °C), which is more than ten times higher than that of the commercial light MgO. This novel mesoporous MgO adsorbent also exhibited high stability during multiple CO2 adsorption/desorption cycles. The excellent CO2 capturing performance was believed to be related to its high specific surface area of 321.3 m2 g−1 and abundant surface active adsorption sites. This work suggested a new synthesis scheme for MgO based CO2 adsorbents at intermediate temperatures, providing a competitive candidate for capturing CO2 from certain sorption enhanced hydrogen production processes.

Mesoporous magnesium oxide nanoparticles derived via complexation-combustion for enhanced performance in carbon dioxide capture.

Magnesium oxide (MgO) is a promising candidate for carbon dioxide (CO2) capture at high temperature applicable to pre-combustion capture in an integrated gasification combined cycle (IGCC) scheme. In this work, mesoporous MgO nanoparticles were synthesized via simple complexation-combustion method by using glycine (G) and urea (U) as fuels (F). The obtained sorbents were thoroughly characterized in terms of the crystalline structure, morphology, nature of the fuel, F/O ratio, and their consequent effects on CO2 sorption. It was observed that due to the complexation followed by combustion in the presence of glycine, MgO with crystallite size as small as∼8nm could be derived. The synthesized MgO nanoparticles exhibited exceptionally high CO2 sorption at elevated temperatures. Furthermore, CO2 sorption isotherms in assistance with FT-IR and DSC experiments demonstrated that the low CO2 uptake at ambient temperature (25-100°C) may be due to the formation of monodentate carbonates, whereas predominant bicarbonates enhance the CO2 uptake at elevated temperatures (100-300°C). MgO-1.5(G) obtained the highest sorption corresponding to 1.34mmol/g at 200°C.

Mesoporous Magnesium Oxide Hollow Spheres as Superior Arsenite Adsorbent: Synthesis and Adsorption Behavior.

Arsenic contamination in natural water has posed a significant threat to global health due to its toxicity and carcinogenity. Adsorption technology is an easy and flexible method for arsenic removal with high efficiency. In this Article, we demonstrated the synthesis of mesoporous MgO hollow spheres (MgO-HS) and their application as high performance arsenite (As(III)) adsorbent. MgO-HS with uniform particle size (∼180 nm), high specific surface area (175 m(2) g(-1)), and distinguished mesopores (9.5 nm in size) have been prepared by hard-templating approach using mesoporous hollow carbon spheres as templates. An ultrahigh maximum As(III) adsorption capacity (Qmax) of 892 mg g(-1) was achieved in batch As(III) removal study. Adsorption kinetic study demonstrated that MgO-HS could enable As(III) adsorption 6 times faster as a commercial MgO adsorbent. The ultrahigh adsorption capacity and faster adsorption kinetics were attributed to the unique structure and morphology of MgO-HS that enabled fast transformation into a flower-like porous structure composed of ultrathin Mg(OH)2 nanosheets. This in situ formed structure provided abundant and highly accessible hydroxyl groups, which enhanced the adsorption performance toward As(III). The outstanding As(III) removal capability of MgO-HS showed their great promise as highly efficient adsorbents for As(III) sequestration from contaminated water.

Facile Synthesis of High-Surface-Area Mesoporous MgO with Excellent High-Temperature CO2 Adsorption Potential

Mesoporous magnesium oxide of high surface area (>350 m2/g) has been synthesized by a simple ammonia precipitation method from an aqueous magnesium nitrate solution. This material has been evaluated for CO2 adsorption in the temperature and pressure regimes relevant to precombustion capture in an integrated gasification combined cycle scheme. CO2 adsorption capacities were also compared with those of magnesium oxides obtained by other synthetic routes such as hydrothermal urea hydrolysis and direct thermal degradation of magnesium nitrate. Mesoporous magnesium oxide shows a CO2 capacity at high temperatures that is comparable or even exceeds the capacity values for this class of high-temperature CO2 adsorbents reported in the literature so far. The materials studied have been characterized by various characterization techniques like powder X-ray diffraction, surface area, pore-size distribution analysis, scanning electron microscopy, and Fourier transform infrared. A cyclic adsorption/desorption study was...