Thermodynamic and kinetic study of synthesised graphene oxide-CuO nanocomposites: A way forward to fuel additive and photocatalytic potentials

Rectangular shaped GO-CuO nanocomposites have gained special attention because of spectacular applications in wastewater treatment. However, due to a lack of research, the fuel additive properties of GO-CuO are still unreported. A proper synthesis and characterisation methods are necessary to investigate the fuel additive properties of GO-CuO. The present research demonstrates the synthesis of graphene oxide (GO) sheets via modified Hummers' method. Further, GO-CuO nanohybrid was prepared by fast, cost-effective, and easy to handle solvothermal approach. The crystal data such as crystal structure, unit cell parameters, space groups, crystal system, and coordinates were explained via XRD analysis. Physical and combustion properties of fuel were analysed at different concentrations (0, 20, 40, 60, and 80 ppm) of diesel-GO-CuO blend for fuel quality parameters. The flash point and fire point of pure diesel oil were observed as 78 and 80 °C which were decreased to 50 and 58 °C, respectively, at 80 ppm concentration. With GO-CuO nanocomposites, the cloud point and pour point decrease until a temperature of −8 °C and − 19 °C, respectively, with a pronounced decrease in the viscosity up to 1.83 mm2/s. Further, the photocatalytic degradation of Methylene Red (MR) dye is studied with the effect of changing H2O2, photocatalyst, and dye concentrations with time. Remarkably, the reaction kinetics and MR degradation of about 94% with sixth-time recyclability were observed. The results of this study showed improved MR degradation when using GO-CuO with H2O2. GO-CuO applications can be utilised to remove other dyes in future and to improve fuel quality parameters

Electrochemical production of sustainable hydrocarbon fuels from CO2 co-electrolysis in eutectic molten melts

Because of the heavy reliance of people on limited fossil fuels as energy resources, global warming has increased to severe levels because of huge CO2 emission into the atmosphere. To mitigate this situation, a green method is presented here for the conversion of CO2/H2O into sustainable hydrocarbon fuels via electrolysis in eutectic molten salts [(KCl-LiCl; 41:59 mol %), (LiOH-NaOH; 27:73 mol %), (KOH-NaOH; 50:50 mol %), and (Li2CO3-Na2CO3-K2CO3; 43.5:31.5:25 mol %)] under the conditions of 1.5-2 V and 225-475 °C depending on the molten electrolyte used. Gas chromatography (GC) and GC-mass spectrometry (MS) techniques were employed to analyze the content of gaseous products. The electrolysis results in hydrocarbon production with maximum 59.30, 87.70, and 99% Faraday efficiencies in the case of molten chloride, molten hydroxide, and molten carbonate electrolytes under the temperatures of 375, 275, and 425 °C, respectively. GC with a flame-ionization detector and a thermal conductivity detector and GC-MS analysis confirmed that H2 and CH4 were the main products in the case of molten chlorides and hydroxides at an applied voltage of 2 V, while longer-chain hydrocarbons (>C1) were obtained only in molten carbonates at 1.5 V. In this way, electricity is transformed into chemical energy. The heating values obtained from the produced hydrocarbon fuels are satisfactory for further application. The practice of using molten salts could be a promising and encouraging technology for further fundamental investigation of sustainable hydrocarbon fuel formation with more product concentrations because of their fast electrolytic conversion rate without the use of a catalyst

Kinetic and equilibrium study of graphene and copper oxides modified nanocomposites for metal ions adsorption from binary metal aqueous solution

Presently, the main cause of pollution of natural water resources is heavy metal ions. The removal of metal ions such as nickel (Ni2+) and cadmium (Cd2+) has been given considerable attention due to their health and environmental risks. In this regard, for wastewater treatment containing heavy metal ions, graphene oxide (GO) nanocomposites with metal oxide nanoparticles (NPs) attained significant importance. In this study, graphene oxide stacked with copper oxide nanocomposites (GO/CuO-NCs) were synthesized and characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and atomic force microscopy (AFM) analytical procedures. The prepared GO/CuO-NCs were applied for the removal of Ni2+ and Cd2+ ions from a binary metal ion system in batch and continuous experiments. The obtained results revealed that GO/CuO-NCs exhibited the highest removal efficiencies of Ni2+ (89.60% ± 2.12%) and Cd2+ (97.10% ± 1.91%) at the optimum values of pH: 8, dose: 0.25 g, contact time: 60 min, and at 50 ppm initial metal ion concentration in a batch study. However, 4 mL/min flow rate, 50 ppm initial concentration, and 2 cm bed height were proved to be the suitable conditions for metal ion adsorption in the column study. The kinetic adsorption data exhibited the best fitting with the pseudo-second-order model. The adsorption isotherm provided the best-fitting data in the Langmuir isotherm model. This study suggested that the GO/CuO nanocomposites have proved to be efficient adsorbents for Ni2+ and Cd2+ ions from a binary metal system

Is Antifibrinolytic Therapy Effective for Preventing Hemorrhage in Patients with Hemophilia Undergoing Dental Extractions? A Systematic Review and Meta-Analysis

Objectives This systematic review aims to analyze the systemic administration of antifibrinolytics (tranexamic acid and aminocaproic acid) to prevent postoperative bleeding in patients with hemophilia. Methods This systematic review was conducted adhering to PRISMA guidelines. Only randomized controlled trials that assessed human subjects of any age or gender with any severity of hemophilia undergoing dental extractions, and systemically administered antifibrinolytic therapy compared to placebo were included. Post-operative bleeding episodes and adverse events were presented. PubMed, Cochrane, Embase, CINAHL, Web of Science, and Scopus were searched through April 15, 2022. The risk ratio (RR) and odds ratio (OR) applying 95% confidence intervals (CI) were computed using RevMan 5.4.1 (Cochrane). Results Two randomized, placebo-controlled trials pooling in a total of 59 patients were pooled in this analysis. Among patients administered antifibrinolytic therapy, 84% reduced risk of post-operative bleeding was reported (RR = 0.16, 95% CI = 0.05–0.47, P = 0.0009). The chances of post-operative bleeding were reduced by 95% among the antifibrotics group (OR = 0.05, 95% CI = 0.01–0.22, P < 0.0001). Conclusion This review finds favorable outcomes for the routine use of antifibrinolytic therapy for dental extractions in hemophiliacs. Further trials are required to rationalize existing evidence