Investigation of theoretical maximum water yield and efficiency-optimized temperature for cyclopentane hydrate-based desalination.

Hydrate-based desalination (HBD) shows promise as a freshwater production technology for saline water. Liquid-phase hydrate formers, with their ability to facilitate hydrate formation at atmospheric pressure, have gained attention for their high energy efficiency in HBD. This study explored cyclopentane (CP) HBD by experimentally measuring the thermodynamic properties of CP hydrate in saline solutions and developing a theoretical framework to estimate the water yield of CP HBD under various operating conditions. The measured dissociation enthalpy of CP hydrate was found to be 12 % and 22 % lower compared to those of propane and R134a hydrates, respectively. The equilibrium dissociation temperatures of CP hydrate at different NaCl concentrations under atmospheric pressure were experimentally measured and then predicted using the Hu-Lee-Sum correlation. The theoretically achievable maximum salinity and water yield for CP HBD were calculated in the temperature range of 268-280 K and the initial salinity range of 0-8 wt.%. Additionally, the concept of HBD heat efficiency, representing the maximum amount of pure water producible per unit of heat, was introduced to identify an optimal operating condition for the HBD process. Efficiency-maximized temperatures, where the HBD heat efficiency reached its peaks, were determined for various initial salinities in the process, for example, 273.4 K for NaCl 3.5 wt.% solution. This novel approach provides invaluable guidance for determining the most energy-efficient operating conditions in the HBD process and establishes a solid foundation for further advancements in this field.

Evaluation of Ibuprofen/Montmorillonite Nano-Clay Composites as an Oral Drug Delivery System and In-Vitro Drug Release Performance.

A formulation for controlled delivery of ibuprofen (IBU) involving montmorillonite (MMT) nanoclays has been proposed. The present work has investigated the beneficial effect of MMT in improving controlled delivery of IBU. The intercalation of IBU into the interlayer of MMT was studied under different processing conditions such as reaction time and initial concentration of IBU. To characterize the IBU/MMT composites, X-ray diffraction (XRD) and Fourier transform infrared spectra (FTIR) were performed. The release behavior of IBU from IBU/MMT composites have been investigated under vitro conditions using buffer media of simulated gastric fluid (pH 1.2) and simulated intestinal fluid (pH 7.4) at 37 °C. Controlled release of IBU from IBU/MMT composite has been observed during in vitro release experiments. Different mathematical models were used for fitting our experimental results, among them the best fitting was found for Higuchi equation based on the parabolic diffusion process.

Application of Silver Nanofluids on Kinetics of Sulfur Hexafluoride Gas Hydrate Formation.

Gas hydrates are nonstoichiometric nano-structured crystalline compounds which are stabilized by gas molecules incorporated in the cages made of hydrogen bonding of water molecules at suitable thermodynamic conditions. The gas hydrate as a technology has been successful for several potential applications in various engineering fields, such as, gas separation, carbon dioxide sequestration, gas storage and transportation, desalination of salt water and wastewater treatment. Recently, metal-based nanofluids are considered as interesting kinetic promoter candidates for accelerating formation of gas hydrates. Although organic-based kinetic promoters are widely studied for the rapid formation of gas hydrates, research of a new material system is still a challenge. In this study, Silver (Ag) nanofluids as kinetic promoter of sulfur hexafluoride (SF6) hydrate were prepared by electrical explosion of pure metal wire in deionized water. The kinetics of SF6 gas hydrates were evaluated with different concentration of Ag nanofluids at condition of 276 K and 0.7 MPa, respectively. The Ag nanofluids, as kinetic nano-prompter, showed excellent effect on the formation of SF6 hydrates.

Preparation and Characterization of Poly Methyl Methacrylate/Clay Nanocomposite Powders by Microwave-Assisted In-Situ Suspension Polymerization.

The PMMA (poly methyl methacrylate)/clay nanocomposite powders were synthesized by In-Situ suspension polymerizations using microwave heating. The PMMA/clay nanocomposites were also sampled using injection moulding to make specimens for material characterization. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) indicated the formation of a highly intercalated clay layer in the nanocomposites. It was found that the microstructure of PMMA/clay nanocomposites was strongly dependent of content of clay. Thermo gravimetric analysis (TGA) indicated an improvement in the thermal stability of nanocomposites compared to that of the pure PMMA. Differential scanning calorimetry (DSC) showed that the nanocomposites had a higher glass transition (Tg) temperature than the PMMA. Fourier-transform infrared (FT-IR) spectroscopy indicated an interaction between the carbonyl group of PMMA and hydroxyl group of the clay. Therefore, a possible reason in enhanced material properties of nanocomposites is that the chemical interaction and nanostructure of PMMA polymer and intercalated inorganic silicate layer has increased the thermal stability of the PMMA/clay nanocomposites.