Carbon Xerogel is an economic choice of material for electrodes with applications in Electric Double Layer Capacitors (EDLCs) and Capacitive DeIonization systems (CDI, particularly for desalination). The objective here is to optimize Carbon Xerogel's performance, specifically its capacitance, through multi-parameter optimization using Response Surface Methodology (RSM). We choose NaOH as the catalyst and select as the optimization parameters (i) the pH of the initial Resorcinol-Formaldehyde-Catalyst (RFC) solution, (ii) Reactants to Liquid mass ratio (R/L) of the RFC solution, and (iii) the Pyrolysis Temperature (PT). For a selected range of these three parameters, we obtain an optimum capacitance of Carbon Xerogel equal to 37.6 F/g with optimized parameters PT = 800, R/L = 30% and pH = 5.7. Through comparing Carbon Xerogel samples synthesized with Na 2 CO 3 versus NaOH as the catalyst, we show that the capacitance not only depends on the pH of the initial RFC solution, but also is a strong function of the catalyst material.

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Nano-confined chemical reactions bear great promise for a wide range of important applications in the near-to-medium term, e.g., within the emerging area of chemical storage of renewable energy. To explore this important trend, in the present work, resorcinol-/formaldehyde-based carbon aerogels were prepared by sol-gel polymerisation of resorcinol, with furfural catalysed by a sodium-carbonate solution using ambient-pressure drying. These aerogels were further carbonised in nitrogen to obtain their corresponding carbon aerogels. Through this study, the synthesis parameters were selected in a way to obtain minimum shrinkage during the drying step. The microstructure of the product was observed using Scanning Electron Microscopy (SEM) and Field Emission Scanning Electron Microscopy (FESEM) imaging techniques. The optimised carbon aerogels were found to have pore sizes of ~21 nm with a specific accessible surface area equal to 854.0 m2/g. Physical activation of the carbon aerogel with CO2 generates activated carbon aerogels with a surface area of 1756 m2/g and a total porosity volume up to 3.23 cm3/g. The product was then used as a scaffold for magnesium/cobalt-hydride formation. At first, cobalt nanoparticles were formed inside the scaffold, by reducing the confined cobalt oxide, then MgH2 was synthesised as the second required component in the scaffold, by infiltrating the solution of dibutyl magnesium (MgBu2) precursor, followed by a hydrogenation reaction. Further hydrogenation at higher temperature leads to the formation of Mg2CoH5. In situ synchrotron X-ray diffraction was employed to study the mechanism of hydride formation during the heating process.

Population growth and increasing global demand for freshwater have raised a serious challenge for the depleting sources of freshwater in the 21st century. Desalination technologies can be a reliable technique for providing freshwater. Capacitive deionization is one of the innovative desalination methods that has received increasing interest. Flow-electrode capacitive deionization (FCDI) (a new architecture of capacitive deionization) is one of the efficient, cost-effective, and environmentally-friendly desalination methods for freshwater production. In this experimental research, the performance of an FCDI system was investigated and the influence of important parameters such as flow rate of flow-electrodes, electrolyte salt concentration of flow-electrodes, and initial feed water concentration will be assessed on the efficiency of desalination operation. In this study, the flow-electrodes operated in short-circuited closed-cycle operation (SCC) mode, and also the feed water operated similarly to the flow-electrodes in closed-cycle. Moreover, in all the experiments, the salt adsorption capacity (SAC) and salt removal efficiency (SRE) was calculated. Herein, by optimizing the above mentioned parameters, the salt removal efficiency of 83% and a SAC value of 29.12 mg/g dry carbon were achieved in 5 hours.

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