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).

Spherical CeO2 nanoparticles prepared using an egg-shell membrane as a bio-template for high CO2 adsorption

A spherical-like mesoporous cerium oxide (CeO2-BT) was prepared through biotemplating method using egg-shell membrane (ESM) as a template. The CeO2-BT has shown a smaller nanoparticle size (30–34 nm) and larger surface area (26.52 m2/g) compared to CeO2 prepared through thermal decomposition method (CeO2-TD). The CeO2-BT has also shown a lattice expansion with the high defect site and oxygen vacancies as evidenced by the Williamson-Hall (W-H) plot. These enhancements have resulted in excellent CO2 uptake of CeO2-BT (1.412 mmol/g), being 12-fold higher than that of CeO2-TD at 1 bar and 25 °C

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

Magnesium oxide-based adsorbents for carbon dioxide capture: Current progress and future opportunities

Adsorption technology has been introduced as one approach to reduce CO2 emissions into the Earth's atmosphere. MgO-based adsorbents are promising due to their abundant availability, wide temperature range, and tuneable physicochemical properties. Over the last decade, there has been a growing number of MgO-based adsorbent studies using various improved approaches that have achieved high CO2 capture performance. For instance, modification using metal/non-metal hybrids and the introduction of promoters, such as alkali metal nitrate/carbonate, and amines to the MgO adsorbent have a significant impact toward enhancing the CO2 uptake capacity and performance stability. Therefore, it is important to provide the latest review on MgO-based adsorbents prepared via various modification strategies using promoters, such as alkali metal nitrate/carbonate (molten salt), amines, and metal oxides, and their relationship with the CO2 uptake performance. In this study, the adsorbent preparation method and CO2 adsorption mechanism are discussed, in which the ambient adsorption pressure conditions, which is typically related to the flue gas of the post-combustion working conditions, were emphasised. Several recommendations for future studies have also been proposed

Solvent dependence of the rheological properties in hydrogel magnetorheological plastomer

This work described the effect of 3-aminopropyltrimethoxysilane (APTMS) functionalization on the mesoporous ceria nanoparticles (MCNs) toward CO2 capture. The MCN and APTMS-loaded MCN (APTMS-MCN) were prepared by the sol-gel and impregnation method, respectively. The functionalization of APTMS on the MCN enhanced the CO2 binding sites which were observed through the formation of carbamate species from the interaction of CO2 with the NH group. This resulted to the increase of CO2 adsorption capacity of APTMS-MCN with 10-fold higher than that of pristine MCNs. For MCNs, CO2 may be adsorbed onto oxygen basic, oxygen vacant, and hydroxyl sites which further formed polydentate, monodentate, bidentate, and hydrogen carbonate species. In addition to these carbonate species, the adsorption of CO2 on APTMS-MCN has largely occurred through the formation of carbamate species which further enhanced its CO2 uptake

Magnesium-based alloys for solid-state hydrogen storage applications: a review

Magnesium hydrides (MgH2) have attracted extensive attention as solid-state H2 storage, owing to their low cost, abundance, excellent reversibility, and high H2 storage capacity. This review comprehensively explores the synthesis and performance of Mg-based alloys. Several factors affecting their hydrogen storage performance were also reviewed. The metals addition led to destabilization of Mg–H bonds to boost the dehydrogenation process. A unique morphology could provide more available active sites for the dissociation/recombination of H2 and allow the activation energy reduction. Also, an appropriate support prevent the agglomeration of Mg particles, hence, sustains their nanosize particles. Moreover, the perspective of avenues for future research presented in this review is expected to act as a guide for the development of novel Mg-based H2 storage systems. New morphological shape of catalysts, more unexplored and highly potential waste materials, and numerous synthesis procedures should be explored to further enhance the H2 storage of Mg-based alloys

Reconstruction of bony facial contour deficiencies with polymethylmethacrylate implants: case report

Facial trauma can be considered one of the most serious aggressions found in the medical centers due to the emotional consequences and the possibility of deformity. In craniofacial surgery, the use of autologous bone is still the first choice for reconstructing bony defects or irregularities. When there is a shortage of donor bone or a patient refuses an intracranial operation, alloplastic materials such as polymethylmethacrylate (PMMA) can be used. The PMMA prosthesis can be pre-fabricated, bringing advantages such as reduction of surgical time, easy technical handling and good esthetic results. This paper describes the procedures for rehabilitating a patient with PMMA implants in the region of the face, recovering the facial contours and esthetics of the patient

Experimental model of distraction osteogenesis in edentulous rats

Distraction osteogenesis (DO) is a surgical technique producing bone lengthening by distraction of the fracture callus. Although a large number of experimental studies on the events associated with DO of craniofacial skeleton have been reported, the few employing rat mandibular bone DO used complicated designs and produced a small volume of newly formed bone. Thus, this study aims to present an original experimental model of mandibular DO in edentulous rats that produces a sufficient quantity and quality of intramembranous bone. Eight male Wistar rats, weighing 75 g, underwent extraction of lower molars. With rats weighing 350 g, right mandibular osteotomy was performed and the distraction device was placed. The distraction device was custom made using micro-implants, expansion screws, and acrylic resin. Study protocol: latency: 6 days, distraction: ¼ turn (0.175 mm) once a day during 6 d, consolidation: 28 d after distraction phase, sacrifice. DO-treated and contralateral hemimandibles were dissected and compared macroscopically and using radiographic studies. Histological sections were obtained and stained with H&E. A distraction gap filled with newly formed and mature bone tissue was obtained. This model of mandibular DO proved useful to obtain adequate quantity and quality of bone to study bone regeneration