Phase equilibria, structure identification, and dissociation enthalpies of HFC-134a hydrates in the presence of NaCl are investigated for potential application in desalination. To verify the influence of NaCl on the thermodynamic hydrate stability of the HFC-134a hydrate, the three-phase (hydrate (H) - liquid water (L W ) - vapor (V)) equilibria of the HFC-134a+NaCl (0, 3.5, and 8.0 wt%)+water systems are measured by both a conventional isochoric (pVT) method and a stepwise differential scanning calorimeter (DSC) method. Both pVT and DSC methods demonstrate reliable and consistent hydrate phase equilibrium points of the HFC-134a hydrates in the presence of NaCl. The HFC-134a hydrate is identified as sII via powder X-ray diffraction. The dissociation enthalpies (ΔH d ) of the HFC-134a hydrates in the presence of NaCl are also measured with a high pressure micro-differential scanning calorimeter. The salinity results in significant thermodynamic inhibition of the HFC-134a hydrates, whereas it has little effect on the dissociation enthalpy of the HFC-134a hydrates. The experimental results obtained in this study can be utilized as foundational data for the hydrate-based desalination process.
Extensive use of fossil fuel resources especially petroleum has resulted in situation to look for alternative fuel sources. Biodiesel offers a good choice due to its renewable nature. In recent times, mainly methanol has been used in transesterification reaction for biodiesel production as it is derived from fossil sources, and biodiesel produced cannot be termed as completely renewable while other alcohols such as ethanol, being obtained from renewable sources such as potatoes, sugarcane, grains, corn and sorghum can be used for transesterification reaction. The aim of this work was to investigate the impact of ethanol on biodiesel production from Karanja oil and then optimise process variables for transesterification process. Further a comparison was done in optimised reaction parameters for methanolysis and ethanolysis. The result of experimental investigation shows that Karanja biodiesel yield of 91.05% was achieved with molar ratio of 10.44:1 for methanol using 1.22% w/w KOH as catalyst for 90.78 min at the temperature of 66.8 °C. On the other hand for, ethanolysis, optimised reaction conditions were, 8.42:1 molar ratio, 61.3 °C reaction temperature with 1.21% of catalyst and 120 min of reaction time to obtain yield of 77.4%.
The nanosheet-structured CuxS thin films used as counter electrodes (CEs) for CdS/CdSe quantum dot sensitized solar cells (QDSSCs) have been in situ prepared via the sulfidation of Cu nanoparticles deposited on F-doped SnO2 glass (FTO glass) substrate by magnetron sputtering method. The thickness of the deposited Cu film affects the morphology and thickness of the obtained CuxS films. The CuxS nanosheet films have good adhesion with FTO glass and the surface exhibits uniform morphology. The characteristics of QDSSCs are studied in more detail by photocurrent-voltage performance measurements, incident photon-to-current conversion efficiency (IPCE) and electrochemical impedance spectroscopy (EIS). The CuxS on FTO glass (CuxS/FTO) CEs show much higher power conversion efficiency (PCE) and IPCE than those of the Pt on FTO (Pt/FTO) CE because of their superior carrier mobility and electro-catalytic ability for the polysulfide redox reactions. Based on an optimal CuxS film thickness of 2.7 μm obtained by the sulfidation of the Cu film thickness of 300 nm on FTO, the best photovoltaic performance with PCE of 3.67% (Jsc = 16.47 mA cm−2, Voc = 0.481 V, FF = 0.46) under full one-sun illumination is achieved.