RESUMO
In this study, we investigated improving the performance of a layered double hydroxide (LDH) for the adsorption of As(III) and As(V) by controlling the morphology of LDH crystals. The LDH was synthesized via a simple coprecipitation method using barely soluble MgO as a precursor and succinic acid (SA) as a morphological control agent. Doping the LDH crystals with carboxylate ions (RCOO-) derived from SA caused the crystals to develop in a radial direction. This changed the pore characteristics and increased the density of active surface sites. Subsequently, SA/MgFe-LDH showed excellent affinity for As(III) and As(V) with maximum sorption densities of 2.42 and 1.60 mmol/g, respectively. By comparison, the pristine MgFe-LDH had sorption capacities of 1.56 and 1.31 mmol/g for As(III) and As(V), respectively. The LDH was effective over a wide pH range for As(III) adsorption (pH 3-8.5) and As(V) adsorption (pH 3-6.5). Using a combination of spectroscopy and sorption modeling calculations, the main sorption mechanism of As(III) and As(V) on SA/MgFe-LDH was identified as inner-sphere complexation via ligand exchange with hydroxyl group (-OH) and RCOO-. Specifically, bidentate As-Fe complexes were proposed for both As(III) and As(V) uptake, with the magnitude of formation varying with the initial As concentration. Importantly, the As-laden adsorbent had satisfactory stability in simulated real landfill leachate. These findings demonstrate that SA/MgFe-LDH exhibits considerable potential for remediation of As-contaminated water.
Assuntos
Arsênio , Hidróxidos , Óxido de Magnésio , Ácido Succínico , Poluentes Químicos da Água , Adsorção , Poluentes Químicos da Água/química , Cinética , Arsênio/química , Ácido Succínico/química , Hidróxidos/química , Óxido de Magnésio/química , Purificação da Água/métodos , Modelos QuímicosRESUMO
Sulfur trioxide (SO3) as a condensable particle matter has a significant influence on atmospheric visibility, which easily arouses formation of haze. It is imperative to control the SO3 emission from the industrial flue gas. Three commonly used basic absorbents, including Ca(OH)2, MgO and NaHCO3 were selected to explore the effects of temperature, SO2 concentration on the SO3 absorption, and the reaction mechanism of SO3 absorption was further illustrated. The suitable reaction temperature for various absorbents were proposed, Ca(OH)2 at the high temperatures above 500°C, MgO at the low temperatures below 320°C, and NaHCO3 at the temperature range of 320-500°C. The competitive absorption between SO2 and SO3 was found that the addition of SO2 reduced the SO3 absorption on Ca(OH)2 and NaHCO3, while had no effect on MgO. The order of the absorption selectivity of SO3 follows MgO, NaHCO3 and Ca(OH)2 under the given conditions in this work. The absorption process of SO3 on NaHCO3 follows the shrinking core model, thus the absorption reaction continues until NaHCO3 was exhausted with the utilization rate of nearly 100%. The absorption process of SO3 on Ca(OH)2 and MgO follows the grain model, and the dense product layer hinders the further absorption reaction, resulting in low utilization of about 50% for Ca(OH)2 and MgO. The research provides a favorable support for the selection of alkaline absorbent for SO3 removal in application.
Assuntos
Poluentes Atmosféricos , Dióxido de Enxofre , Dióxido de Enxofre/química , Poluentes Atmosféricos/química , Poluentes Atmosféricos/análise , Óxidos de Enxofre/química , Modelos Químicos , Óxido de Magnésio/química , Hidróxido de Cálcio/químicaRESUMO
BACKGROUND: Periodontal Disease (PD) associated with Type 2 Diabetes Mellitus (T2DM) is a chronic condition that affects the oral cavity of people living with T2DM. The mechanisms of the interaction between type 2 Diabetes Mellitus and Periodontal diseases are complex and involve multiple pathophysiological pathways related to the systemic inflammatory process and oxidative stress. Non-surgical periodontal treatment (NSTP) is considered the standard for the management of this disease; however, patients with systemic conditions such as type 2 Diabetes Mellitus do not seem to respond adequately. For this reason, the use of complementary treatments has been suggested to support non-surgical periodontal treatment to reduce the clinical consequences of the disease and improve the systemic conditions of the patient. The use of zinc gluconate and magnesium oxide as an adjunct to non-surgical periodontal treatment and its effects on periodontal clinical features and oxidative stress in patients with Periodontal diseases -type 2 Diabetes Mellitus is poorly understood. METHODS: A quasi-experimental study was performed in patients with periodontal diseases associated with T2DM. Initially, 45 subjects who met the selection criteria were included. 19 were assigned to a control group [non-surgical periodontal treatment] and 20 to the experimental group (non-surgical periodontal treatment + 500 mg of magnesium oxide and 50 mg of zinc gluconate for oral supplementation for 30 days) and the data of 6 patients were eliminated. Sociodemographic characteristics, physiological factors, biochemical parameters, and clinical features of periodontal diseases were assessed. RESULTS: In this research a change in periodontal clinical characteristics was observed, which has been associated with disease remission. Additionally, a shift in MDA levels was presented for both groups. Furthermore, the supplementation group showed an increase in antioxidant enzymes when compared to the group that only received NSPT. CONCLUSION: The use of Zinc gluconate and magnesium oxide can serve as a complementary treatment to non-surgical periodontal treatment, that supports the remission of PD as a result of regulation-reduction of oxidative biomarkers and increase in antioxidant enzymes activity. TRIAL REGISTRATION: https://www.isrctn.com ISRCTN 14,092,381. September 13º 2023. Retrospective Registration.
Assuntos
Antioxidantes , Diabetes Mellitus Tipo 2 , Gluconatos , Estresse Oxidativo , Humanos , Estresse Oxidativo/efeitos dos fármacos , Diabetes Mellitus Tipo 2/complicações , Feminino , Pessoa de Meia-Idade , Masculino , Gluconatos/uso terapêutico , Antioxidantes/uso terapêutico , Óxido de Magnésio/uso terapêutico , Suplementos Nutricionais , Zinco/uso terapêutico , Magnésio/uso terapêutico , Doenças Periodontais/tratamento farmacológico , Doenças Periodontais/terapia , AdultoRESUMO
Allogeneic bone grafts are used to treat bone defects in orthopedic surgery, but the osteogenic potential of artificial bones remains a challenge. In this study, we developed a ß-tricalcium phosphate (ß-TCP) formulation containing MgO, ZnO, SrO, and SiO2 and compared its bone-forming ability with that of ß-TCP without biological elements. We prepared ß-TCP discs with 60% porosity containing 1.0 wt% of these biological elements. ß-TCP scaffolds were loaded with bone marrow-derived mesenchymal stem cells (BMSC) from 7-week-old male rats and cultured for 2 weeks. ALP activity and mRNA expression of osteogenic markers were evaluated. In addition, scaffolds were implanted subcutaneously in rats and analyzed after 7 weeks. In vitro, the MgO group showed lower Ca concentrations and higher osteogenic marker expression compared to controls. In vivo, the MgO group showed higher ALP activity compared to controls, and RT-qPCR analysis showed significant expression of BMP2 and VEGF. Histopathology, fluorescent immunostaining, and micro-CT also showed relatively better bone formation in the MgO group. ß-TCP with MgO may enhance bone morphology in vitro and in vivo and improve the prognosis of patients with substantial and refractory bone defects.
Assuntos
Fosfatos de Cálcio , Óxido de Magnésio , Células-Tronco Mesenquimais , Osteogênese , Alicerces Teciduais , Animais , Osteogênese/efeitos dos fármacos , Fosfatos de Cálcio/farmacologia , Fosfatos de Cálcio/química , Ratos , Masculino , Células-Tronco Mesenquimais/metabolismo , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/citologia , Óxido de Magnésio/farmacologia , Óxido de Magnésio/química , Alicerces Teciduais/química , Proteína Morfogenética Óssea 2/metabolismo , Proteína Morfogenética Óssea 2/genética , Microtomografia por Raio-X , Ratos Sprague-Dawley , Fosfatase Alcalina/metabolismo , Células Cultivadas , Engenharia Tecidual/métodos , Diferenciação Celular/efeitos dos fármacos , Fator A de Crescimento do Endotélio Vascular/metabolismo , Fator A de Crescimento do Endotélio Vascular/genéticaRESUMO
Magnesium is one of the recommended treatments for calcium stone formers (CSFs) with hyperoxaluria. In this study, we compared the effect of magnesium oxide (MgO) or magnesium citrate (MgCit) with placebo on 24-hour urine (24-U) metabolites and the calcium oxalate supersaturation index (CaOx SS). In a randomized, double-blind, placebo-controlled clinical trial, 90 CSFs with idiopathic hyperoxaluria were recruited from a tertiary stone prevention clinic. Patients were randomly assigned into three groups: 120 mg MgO, 120 mg MgCit or placebo (supplements were taken three times per day, with meals). Finally, 76 patients were included in the final analysis. Analyses of 24-U were performed at baseline and after eight weeks. Study outcomes included changes in 24-U oxalate, magnesium, citrate, and CaOx SS. Dietary factors were controlled by 24-hour food recalls. Repeated measure ANOVA was used to compare the results. After the intervention, both MgO and MgCit supplements decreased 24-U oxalate excretion (-8.13±16.45 in the MgO group and -16.99±18.02 in the MgCit group) and CaOx SS compared to the placebo, with the effects of MgCit reaching statistical significance (p=0.011 and p=0.010, respectively). An increasing trend was observed for 24-U magnesium and citrate excretion without significant differences among groups. Interestingly, MgCit exhibited a significantly greater inhibitory effect on 24-U oxalate in patients with normal urine magnesium levels (p=0.021). Clinically, both MgO and MgCit reduced 24-U oxalate and CaOx SS compared to placebo. However, MgCit demonstrated a greater effect, especially in patients with normal urine magnesium levels.
Assuntos
Suplementos Nutricionais , Hiperoxalúria , Cálculos Renais , Óxido de Magnésio , Humanos , Óxido de Magnésio/uso terapêutico , Óxido de Magnésio/administração & dosagem , Feminino , Masculino , Cálculos Renais/urina , Cálculos Renais/prevenção & controle , Cálculos Renais/tratamento farmacológico , Cálculos Renais/metabolismo , Adulto , Hiperoxalúria/urina , Hiperoxalúria/tratamento farmacológico , Hiperoxalúria/complicações , Método Duplo-Cego , Fatores de Risco , Pessoa de Meia-Idade , Ácido Cítrico/urina , Compostos de Magnésio/uso terapêutico , Compostos de Magnésio/urina , Compostos de Magnésio/farmacologia , Compostos de Magnésio/administração & dosagem , Compostos OrganometálicosRESUMO
This study investigates the synthesize of activated carbon for carbon dioxide adsorption using palm kernel shell (PKS), a by-product of oil palm industry. The adsorbent synthesis involved a simple two-step carbonization method. Firstly, PKS was activated with potassium oxide (KOH), followed by functionalization with magnesium oxide (MgO). Surface analysis revealed that KOH activated PKS has resulted in a high specific surface area of 1086 m2/g compared to untreated PKS (435 m2/g). However, impregnation of MgO resulted in the reduction of surface area due to blockage of pores by MgO. Thermogravimetric analysis (TGA) demonstrated that PKS-based adsorbents exhibited minimal weight loss of less than 30% up to 500 °C, indicating their suitability for high-temperature applications. CO2 adsorption experiments revealed that PKS-AC-MgO has achieved a higher adsorption capacity of 155.35 mg/g compared to PKS-AC (149.63 mg/g) at 25 °C and 5 bars. The adsorption behaviour of PKS-AC-MgO was well fitted by both the Sips and Langmuir isotherms, suggesting a combination of both heterogeneous and homogeneous adsorption and indicating a chemical reaction between MgO and CO2. Thermodynamic analysis indicated a spontaneous and thermodynamically favourable process for CO2 capture by PKS-AC-MgO, with negative change in enthalpy (- 0.21 kJ/mol), positive change in entropy (2.44 kJ/mol), and negative change in Gibbs free energy (- 729.61 J/mol, - 790.79 J/mol, and - 851.98 J/mol) across tested temperature. Economic assessment revealed that the cost of PKS-AC-MgO is 21% lower than the current market price of commercial activated carbon, indicating its potential for industrial application. Environmental assessment shows a significant reduction in greenhouse gas emissions (381.9 tCO2) through the utilization of PKS-AC-MgO, underscoring its environmental benefits. In summary, the use of activated carbon produced from PKS and functionalised with MgO shows great potential for absorbing CO2. This aligns with the ideas of a circular economy and sustainable development.
Assuntos
Arecaceae , Dióxido de Carbono , Dióxido de Carbono/química , Adsorção , Arecaceae/química , Carbono/química , Óxido de Magnésio/química , Carvão Vegetal/química , Óleo de Palmeira/químicaRESUMO
Pb-contaminated soil poses significant environmental and health risks as well as soil stability issues. Research on sandy soils highlights CO2-enhanced reactive MgO as a promising solution for improving the solidification of Pb-contaminated soils. However, carbonation effects can differ markedly between soil types owing to varying soil properties. In this study, we evaluated the effects of CO2-enhanced reactive MgO on the engineering and environmental characteristics of Pb-contaminated red clay and explored its mechanism of carbonation solidification. The results showed that CO2-enhanced reactive MgO increased the strength of Pb-contaminated red clay to over 3 MPa within 1 h, which was approximately 25 times the strength of untreated soil (0.2 MPa) and significantly higher than that of reactive MgO-treated, uncarbonated soil (0.8 MPa). The pH of the carbonated soil (9-10) facilitated Pb2+ immobilization, and the increase over the initial parameter elevated the electrical conductivity value. Moreover, CO2-enhanced reactive MgO reduced the Pb2+ leaching concentration to below 0.1 mg/L, even at high Pb concentrations (10,000 mg/kg). Pb2+ transformed into lead carbonates during the carbonation process, with the hydrated magnesium carbonates forming a dense internal structure. This solidification mechanism included chemical precipitation, physical adsorption, and encapsulation. Notably, the carbonation time should be controlled within 1 h to prevent soil expansion. Together, these findings support the potential of CO2-enhanced reactive MgO for efficient and low-carbon application in the solidification of Pb-contaminated red clay.
Assuntos
Dióxido de Carbono , Argila , Chumbo , Poluentes do Solo , Solo , Dióxido de Carbono/química , Poluentes do Solo/química , Chumbo/química , Argila/química , Solo/química , Óxido de Magnésio/químicaRESUMO
Lately, children's daily consumption of some products, such as cereals and candies, has been rising, which provides a compelling rationale for determining any metallic substances that may be present. Monitoring the concentration of certain metals, like nickel, in these products is necessary due to medical issues in humans when consumed regularly. So, in this work, a novel and highly selective carbon paste as a Ni(II) ion-selective sensor was prepared and investigated using ceramic magnesium aluminum spinel nanoparticles as the ionophore and tritolyl phosphate (TOCP) as a plasticizer. A modified co-precipitation method was used to synthesize the spinel nanoparticles. X-ray diffraction, scanning electron microscope with EDAX, transmission electron microscope, and BET surface area were used to determine the phase composition, microstructure, pores size, particle size, and surface area of the synthesized nanoparticles. The spinel nanoparticle was found to have a nano crystallite size with a cubic crystal system, a particle size ranging from 17.2 to 51.52 nm, mesoporous nature (average pore size = 8.72 nm), and a large surface area (61.75 m2/g). The composition ratio of graphite carbon as a base: TOCP as binder: spinal as ionophore was 67.3:30.0:2.7 (wt%) based on potentiometric detections over concentrations from 5.0 × 10-8 to 1.0 × 10-2 mol L-1 with LOD of 5.0 × 10-8 mol L-1. A measurement of 29.22 ± 0.12 mV decade-1 over pH 2.0-7.0 was made for the Nernstian slope. This sensor demonstrated good repeatability over nine weeks and a rapid response of 8 s. A good selectivity was shown for Ni(II) ions across many interferents, tri-, di-, and monovalent cations. The Ni(II) content in spiked real samples, including cocaine, sweets, coca, chocolate, carbonated drinks, cereals, and packages, were measured. The results obtained indicated no significant difference between the proposed potentiometric method and the officially reported ICP method according to the F- and t-test data. In addition to utilizing ANOVA statistical analysis, validation procedures have been implemented, and the results exceed the ICP-MS methodology.
Assuntos
Níquel , Níquel/análise , Níquel/química , Humanos , Criança , Óxido de Magnésio/química , Técnicas Eletroquímicas/métodos , Óxido de Alumínio/química , Nanopartículas/química , Magnésio/química , Magnésio/análise , Íons/análise , Difração de Raios X , Ionóforos/químicaRESUMO
Given the widespread clinical demand, addressing irregular cranial bone defects poses a significant challenge following surgical procedures and traumatic events. In situ-formed injectable hydrogels are attractive for irregular bone defects due to their ease of administration and the ability to incorporate ceramics, ions, and proteins into the hydrogel. In this study, a multifunctional hydrogel composed of oxidized sodium alginate (OSA)-grafted dopamine (DO), carboxymethyl chitosan (CMCS), calcium ions (Ca2+), nanohydroxyapatite (nHA), and magnesium oxide (MgO) (DOCMCHM) was prepared to address irregular cranial bone defects via dynamic Schiff base and chelation reactions. DOCMCHM hydrogel exhibits strong adhesion to wet tissues, self-healing properties, and antibacterial characteristics. Biological evaluations indicate that DOCMCHM hydrogel has good biocompatibility, in vivo degradability, and the ability to promote cell proliferation. Importantly, DOCMCHM hydrogel, containing MgO, promotes the expression of osteogenic protein markers COL-1, OCN, and RUNX2, and stimulates the formation of new blood vessels by upregulating CD31. This study could provide meaningful insights into ion therapy for the repair of cranial bone defects.
Assuntos
Alginatos , Antibacterianos , Quitosana , Hidrogéis , Crânio , Hidrogéis/química , Hidrogéis/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Quitosana/química , Quitosana/análogos & derivados , Quitosana/farmacologia , Animais , Alginatos/química , Crânio/efeitos dos fármacos , Crânio/patologia , Crânio/diagnóstico por imagem , Crânio/lesões , Óxido de Magnésio/química , Óxido de Magnésio/farmacologia , Regeneração Óssea/efeitos dos fármacos , Dopamina/química , Dopamina/farmacologia , Durapatita/química , Durapatita/farmacologia , Camundongos , Proliferação de Células/efeitos dos fármacos , Cálcio/metabolismo , Cálcio/química , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Osteogênese/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacosRESUMO
In recent years, there has been a growing interest in utilizing spinel ferrite and their nanocomposites as Fenton-like catalysts. The use of these materials offers numerous advantages, including ability to efficiently degrade pollutants and potential for long-term and repeated use facilitated by their magnetic properties that make them easily recoverable. The remarkable catalytic properties, stability, and reusability of these materials make them highly attractive for researchers. This paper encompasses a comprehensive review of various aspects related to the Fenton process and the utilization of spinel ferrite and their composites in catalytic applications. Firstly, it provides an overview of the background, principles, mechanisms, and key parameters governing the Fenton reaction, along with the role of physical field assistance in enhancing the process. Secondly, it delves into the advantages and mechanisms of H2O2 activation induced by different spinel ferrite and their composites for the removal of organic pollutants, shedding light on their efficacy in environmental remediation. Thirdly, the paper explores the application of these materials in various Fenton-like processes, including Fenon-like, photo-Fenton-like, sono-Fenton-like, and electro-Fenton-like, for the effective removal of different types of contaminants. Furthermore, it addresses important considerations such as the toxicity, recovery, and reuse of these materials. Finally, the paper presents the challenges associated with H2O2 activation by these materials, along with proposed directions for future improvements.
Assuntos
Compostos Férricos , Peróxido de Hidrogênio , Ferro , Catálise , Peróxido de Hidrogênio/química , Compostos Férricos/química , Ferro/química , Nanocompostos/química , Óxido de Alumínio , Óxido de MagnésioRESUMO
Seaweed waste, abundant and rich in plant-stimulating properties, has the potential to be transformed into valuable soil amendments through proper composting and utilization management. Given its low carbon-to-nitrogen ratio, co-composting seaweed with carbon-rich cornstarch dregs is an effective strategy. However, the potential application of co-composting largely depends on the efficiency of the composting and the quality of the product. This study explores the effects of adding 10 % corn stalk biochar to a co-composting system of seaweed and cornstarch dregs, alongside varying buffering capacities of phosphates (KH2PO4 and K2HPO4·3H2O-KH2PO4) and MgO, on the degradation efficiency of organic matter, nitrogen transformation, and humification. The results indicate that the addition of biochar and salts enhances the oxygen utilization rate (OUR) and cellulase activity during the thermophilic phase. Additionally, X-ray diffraction (XRD) and parallel factor analysis (PARAFAC) demonstrate more intense solubilization and transformation of proteinaceous substances, along with cellulose degradation. These processes are crucial for enhancing organic matter degradation and humification, significantly boosting degradation (with an increase of 28.6 % to 33.8 %) and humification levels (HA/FA increased by 37.1 % to 49.6 %). Specifically, groups with high buffering capacity significantly promote the formation of NO3--N and NH4+-N, and a higher degree of humification, creating an optimal environment for significantly improving nitrogen retention (increased by 4.80 %). Additionally, this treatment retains and slightly enhances the plant-stimulating properties of seaweed. These findings underscore the potential of integrating biochar with specific ratios of phosphates and MgO to enhance composting efficiency and product quality while preserving the plant-stimulating effects of seaweed.
Assuntos
Carvão Vegetal , Compostagem , Óxido de Magnésio , Nitrogênio , Fosfatos , Alga Marinha , Alga Marinha/química , Carvão Vegetal/química , Óxido de Magnésio/química , Compostagem/métodos , Zea mays , Amido/química , Substâncias Húmicas/análise , Solo/químicaRESUMO
The significant production of municipal solid waste incineration fly ash (MSWI FA) underscores the importance of developing efficient solidification materials. This study employed MgO and CaO for immobilizing MSWI FA (with a 70% fly ash incorporation), and the immobilization effect was compared with that of Portland cement (PC). Experimental findings revealed that MgO exhibited the most effective stabilization for heavy metals (Cd, Cu, Pb, and Zn) compared to CaO and PC. XRD, FTIR, TG, and SEM analysis indicated that the principal hydration products in MSWI FA binders solidified with MgO, CaO, and PC were Mg(OH)2, CaCO3, and C-S-H gel, respectively. Mg(OH)2 efficiently immobilized heavy metals through chemical complexation and surface adsorption mechanisms. The MgO-treated MSWI FA demonstrated the highest residual fractions and the lowest easily leachable fractions. Moreover, the leaching characteristics of heavy metals were significantly influenced by the pH level, so MgO-treated MSWI FA with a leachate pH of 9.18 achieved the precipitation and stabilization of most heavy metals. In summary, this study provided an effective material selection for MSWI FA immobilization and presented a novel strategy for MSWI FA management.
Assuntos
Compostos de Cálcio , Cinza de Carvão , Materiais de Construção , Incineração , Óxido de Magnésio , Metais Pesados , Óxidos , Cinza de Carvão/química , Metais Pesados/análise , Metais Pesados/química , Óxido de Magnésio/química , Materiais de Construção/análise , Compostos de Cálcio/química , Óxidos/química , Incineração/métodos , Resíduos Sólidos/análise , Adsorção , Eliminação de Resíduos/métodosRESUMO
Microbially induced carbonate precipitation (MICP) is a promising technique for remediating heavy metal-contaminated soils. However, the effectiveness of MICP in immobilizing Cd in alkaline calcareous soils, especially when applied in agricultural soils, remains unclear. Biochar and magnesium oxide are two environmentally friendly passivating materials, and there are few reports on the combined application of MICP with passivating materials for remediating heavy metal-contaminated soils. Additionally, the number of treatments with MICP cement and the concentration of calcium chloride during the MICP process can both affect the effectiveness of heavy metal immobilization by MICP. Therefore, we conducted MICP and MICP-biochar-magnesium oxide treatments on agricultural soils collected from Baiyin, Gansu Province (pH = 8.62), and analyzed the effects of the number of treatments with cement and the concentration of calcium chloride on the immobilization of Cd by MICP and combined treatments. The results showed that early-stage MICP could immobilize exchangeable cadmium and increase the residual cadmium content, especially with high-concentration calcium chloride MICP treatment. However, in the later stage, soil nitrification and exchange processes led to the dissolution of carbonate-bound cadmium and cadmium activation. The fixing effect of MICP influence whether the MICP-MgO-biochar is superior to the MgO-biochar. Four treatments with cement were more effective than single treatment in MICP-biochar-magnesium oxide treatment, and the MICP-biochar-magnesium oxide treatment with four treatments was the most effective, with passivation rates of 40.7% and 46.6% for exchangeable cadmium and bioavailable cadmium, respectively. However, attention should be paid to the increase in soil salinity. The main mechanism of MICP-magnesium oxide-biochar treatment in immobilizing cadmium was the formation of Cd(OH)2, followed by the formation of cadmium carbonate.
Assuntos
Agricultura , Cádmio , Carbonatos , Carvão Vegetal , Óxido de Magnésio , Poluentes do Solo , Solo , Cádmio/metabolismo , Óxido de Magnésio/química , Poluentes do Solo/metabolismo , Carbonatos/química , Solo/química , Agricultura/métodos , Carvão Vegetal/química , Recuperação e Remediação Ambiental/métodos , Microbiologia do SoloRESUMO
The development of new polymer nanocomposites or antibacterial coatings is crucial in combating drug-resistant infections, particularly bacterial infections. In this study, a new chitosan polymer based nanocomposite reinforced with magnesium oxide nanopowders and carbon quantum dots was fabricated by sol-gel technique and coated on 316 L stainless steel. In order to gaining the optimal amount of components to achieve the maximum antibacterial properties, the effect of concentration of nanocomposite components on its antibacterial properties was investigated. Crystal structure, microstructure, elemental dispersion, size distribution, chemical composition and morphology of nanocomposite and coating were characterized with various analyses. The obtained results exhibited that the carbon quantum dot and magnesium oxide nanopowders were distributed uniformly and without agglomeration in the chitosan matrix and created a uniform coating. The antibacterial properties of the synthesized samples against Staphylococcus aureus bacteria (gram positive) were evaluated using disk diffusion and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) antibacterial tests. The inhibition growth zone formed around the antibiotic and nanocomposite 25 mg/ml under dark and light was about 32 and 14, 11 mm, respectively. Also, MIC and MBC values for final nanocomposite were 62.5 and 125 µg/ml, respectively.
Assuntos
Antibacterianos , Quitosana , Óxido de Magnésio , Testes de Sensibilidade Microbiana , Nanocompostos , Staphylococcus aureus , Quitosana/química , Quitosana/farmacologia , Nanocompostos/química , Óxido de Magnésio/química , Óxido de Magnésio/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Antibacterianos/farmacologia , Antibacterianos/química , Pontos Quânticos/química , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/farmacologiaRESUMO
The isomerization of glucose is a crucial step for biomass valorization to downstream chemicals. Herein, highly dispersed MgO doped biochar (BM-0.5@450) was prepared from rice straw via a solvent-free ball milling pretreatment and pyrolysis under nitrogen conditions. The nano-MgO doped biochar demonstrated enhanced conversion of glucose in water at low temperatures. A 31 % yield of fructose was obtained from glucose over BM-0.5@450 at 50 °C with 80.0 % selectivity. At 60 °C for 140 min, BM-0.5@450 achieved a 32.5 % yield of fructose. Compared to catalyst synthesized from conventional impregnation method (IM@450), the BM-0.5@450 catalyst shows much higher fructose yields (32.5 % vs 25.9 %), which can be attributed to smaller crystallite size of MgO (11.32 nm vs 19.58 nm) and homogenous distribution. The mechanism study shows that the activated MgOH+·OH- group by water facilitated the deprotonation process leading to the formation of key intermediate enediol.
Assuntos
Carvão Vegetal , Glucose , Óxido de Magnésio , Carvão Vegetal/química , Óxido de Magnésio/química , Glucose/química , Isomerismo , Catálise , Oryza/química , Frutose/química , Temperatura Baixa , TemperaturaRESUMO
The present work was designed to synthesize Ag2O-supported MgO/rGO nanocomposites (NCs) via green method using Phoenix leaf extract for improved photocatalytic and anticancer activity. Green synthesized Ag2O-supported MgO/rGO NCs were characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), Raman, ultraviolet-visible (UV-vis) spectroscopy, and photoluminescence (PL) spectroscopy, and gas chromatography-mass spectroscopy (GC-MS) was applied to examine the chemical components of the Phoenix leaf extract. Characterization data confirmed the preparation of MgO NPs, Ag2O-MgO NCs, and Ag2O-MgO/rGO NC with particle size of 26-28 nm. UV-vis study exhibited that the band gap energy of MgO NPs, Ag2O-MgO NCs, and Ag2O-MgO/rGO NC were in the range of 3.53-3.43 eV. The photocatalytic results showed that the photodegradation of Rh B dye of Ag2O-supported MgO/rGO NCs (82.81%) was significantly higher than pure MgO NPs. Additionally, the biological response demonstrates that the Ag2O-supported MgO/rGO NCs induced high cytotoxicity against MCF-7 cancer cells for 24 h and 48 h compared with both pure MgO NPs and Ag2O-MgO NCs. This study suggests that the adding of Ag2O and rGO sheets played significant role in the enhanced photocatalytic and anticancer performance of MgO NPs.
Assuntos
Antineoplásicos , Óxido de Magnésio , Nanocompostos , Extratos Vegetais , Folhas de Planta , Nanocompostos/química , Extratos Vegetais/química , Antineoplásicos/farmacologia , Antineoplásicos/química , Folhas de Planta/química , Humanos , Catálise , Óxido de Magnésio/química , Compostos de Prata/química , Química Verde , Grafite/química , Óxidos/químicaRESUMO
This study presents a comprehensive investigation into NiXCo1-xFe2O4 (x = 0.5) spinel nanoparticles synthesized through a one-pot hydrothermal method using Co(NO3)2.6H2O and Ni(NO3)2.6H2O salts. XRD, FTIR, FESEM, and VSM analyses confirmed a cubic structure of NiXCo1-xFe2O4 (x = 0.5) nanoparticles without impurities. These nanoparticles exhibit efficient Zn (II) adsorption characteristics, following Langmuir isotherm and pseudo-second-order kinetics. The maximum adsorption capacity was measured to be 666.67 mg g-1 at pH = 7, with mechanisms involving both electrostatic attraction and cation exchange. Desorption studies indicate more than 75% Zn (II) recovery in an acidic environment (pH = 2) after three cycles. Computational analysis was used to validate the experimental results through Molecular Dynamics simulations, initially focusing on NiXCo1-xFe2O4 (x = 0.5). Further exploration involved variations in x at 0.25 and 0.75 to identify the optimal Ni and Co ratio in this bivalent cation spinel ferrite. Computational analyses reveal the superior performance of NiXCo1-xFe2O4 (x = 0.75) in Zn (II) removal, supported by radial distribution analysis, VdW energy, Coulombic energy, mean square displacement (MSD), root mean square displacement (RMSD), and interaction energy. This comprehensive study provides valuable insights into the adsorption behavior and structural stability of NiXCo1-xFe2O4 nanoparticles, showcasing potential applications in Zn (II) removal.
Assuntos
Cobalto , Compostos Férricos , Níquel , Zinco , Adsorção , Compostos Férricos/química , Cobalto/química , Zinco/química , Níquel/química , Cinética , Poluentes Químicos da Água/química , Óxido de Alumínio/química , Simulação de Dinâmica Molecular , Nanopartículas/química , Concentração de Íons de Hidrogênio , Óxido de MagnésioRESUMO
This work aims to demonstrate the effect of ZrO2 and MgO inclusion into the Poly(methyl methacrylate) (PMMA). To fabricate novel hybrid composites via heat cure method, various composites (PZM2, PZM4 and PZM6) were synthesized in the system [(95-x) PMMA + 5 ZrO2 + x MgO] (x = 2, 4, and 6) respectively. Density of the prepared composites were determined and varying between 1.035-1.152 g/cm3. X-ray Diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) followed by EDAX and mechanical testing were performed to evaluate the fabricated composite properties. Moreover, to explore the structure of the fabricated composites the 13 C CP-MAS SSNMR and 1 H-13 C Phase-Modulated Lee Goldberg (PMLG) HETCOR Spectrum were recorded which clarify chemical shifting and motional dynamics of the composites. Mechanical tests were performed by UTM and the obtained parameters such as compressive strength, Young's modulus, fracture toughness, brittleness coefficient, flexural strength and flexural modulus are found to be in the range of 91-100 MPa, 0.48-0.51 GPa, 9.122-9.705 MPa.m1/2, 0.66-0.815, 51.03-42.78 MPa and 499-663 MPa respectively. Some more mechanical parameters such as proportional limit, elastic limit, failure strength, modulus of resilience and modulus of toughness were also calculated. Furthermore, tribological properties were also determined and the coefficient of friction (COF) was decreased by 17.4 % and 38 % for composite PZM6 at 20 N and 40 N as compared to the composite PZM2 and the lowest wear volume of 1.55 mm3 was observed for PZM2, whereas the maximum volume loss of 5.64 mm3 is observed for composite PZM6. To check out the biocompatibility, cytotoxicity and genotoxicity of the fabricated composites the Trypan-blue assay was also performed for PZM2 and PZM6 composites. Dissection on the gut of larvae was also performed on the both composites followed by DAPI and DCFH-DA staining. Therefore, these synthesized samples can be used for the fabrication of denture materials.
Assuntos
Resinas Compostas , Resistência à Flexão , Óxido de Magnésio , Teste de Materiais , Microscopia Eletrônica de Varredura , Polimetil Metacrilato , Difração de Raios X , Zircônio , Zircônio/química , Polimetil Metacrilato/química , Espectroscopia de Infravermelho com Transformada de Fourier , Resinas Compostas/química , Óxido de Magnésio/química , Propriedades de Superfície , Módulo de Elasticidade , Força Compressiva , Materiais Dentários/químicaRESUMO
This study develops a composite bone graft of CaO-MgO-SiO2 glass-ceramic and CaSO4 [abbreviated as (CMS)3-x(CS)x] via the sponge replication technique with weight fractions of x = 0, 1, 1.5, 2, and 3. The (CMS)1.5(CS)1.5 composite displays a superior degradability and, a suitable compressive strength of â¼3 MPa, and excellent cell proliferation and differentiation. The in vivo rat femur test in the hybrid-pore (CMS)1.5(CS)1.5 composite granules achieves a higher rate of bone formation, which is â¼2.7 times better than that of the commercial HAP/ß-TCP at 12 weeks. Improved expressions of osteocyte and mature osteocyte marker genes, namely (Spp1, Dmp1, and Fgf23), were observed in the (CMS)1.5(CS)1.5 group, indicating a faster differentiation into mature bone tissue. The ions release of (CMS)1.5(CS)1.5 through the ERK1/2 signaling pathway promotes osteogenic differentiation. The high bone generation rate can be attributed to faster active ions release and modified surface topography. This work highlights an excellent bone graft candidate for clinical applications in orthopedic surgery.
Assuntos
Cerâmica , Osteogênese , Cerâmica/química , Animais , Osteogênese/efeitos dos fármacos , Ratos , Diferenciação Celular/efeitos dos fármacos , Compostos de Cálcio/química , Ratos Sprague-Dawley , Proliferação de Células/efeitos dos fármacos , Óxidos/química , Dióxido de Silício/química , Masculino , Substitutos Ósseos/química , Substitutos Ósseos/farmacologia , Transplante Ósseo/métodos , Óxido de Magnésio/química , Propriedades de Superfície , FêmurRESUMO
This study aimed to evaluate the effect of adding liquid extract of algae (Hypnea musciformis, Grateloupia acuminata, and Sargassum muticum) (HGS) and Magnesium oxide nanoparticles (MgO NPs) using this extract to rear water of Oreochromis niloticus, on improving culture water indices, growth performance, digestive enzyme, hemato-biochemical characters, immune, antioxidative responses, and resistance after challenged by Aeromonas hydrophila with specific refer to the potential role of the mixture in vitro as resistance against three strains bacteria (Aeromonas sobria, Pseudomonas fluorescens, P. aeruginosa) and one parasite (Cichlidogyrus tilapia). The first group represented control, HGS0, whereas the other group, HGS5, HGS10, and HGS15 mL-1 of liquid extract, as well as all groups with 7.5⯵gâ¯mL-1 MgO-NPs added to culture water of O. niloticus, for 60 days. Data showed that increasing levels at HGS 10 and HGS15 mL-1 in to-culture water significantly enhanced growth-stimulating digestive enzyme activity and a significantly improved survival rate of O. niloticus after being challenged with A. hydrophila than in the control group. The total viability, coliform, fecal coliform count, and heavy metal in muscle partially decreased at HGS 10 and HGS15 mL-1 than in the control group. Correspondingly, the highest positive effect on hemato-biochemical indices was noticed at levels HGS 10 and HGS15 mL-1. Fish noticed an improvement in immune and antioxidant indices compared to control groups partially at HGS 10 and HGS15 mL-1. Interestingly, fish cultured in rearing water with the mixture provided downregulated the related inflammatory genes (HSP70, TNF, IL-1ß, and IL-8) partially at HGS15 mL-1. In vitro, the mixture showed positive efficiency as an antibacterial and partially antiparasitic at HGS 10 and HGS15 mL-1. This study proposes utilizing a mixture of (HGS) and (MgO-NPs) with optimum levels of 10-15â¯mL-1 in cultured water to improve water indices, growth, health status, and increased resistance of O. niloticus against bacterial and parasitic infection.