Modeling and Experimental Investigation of Sulfurous Compounds Removal from Gas Condensate through Ultrasound-Assisted Oxidative Desulfurization Method.

This study employed an ultrasound-assisted oxidative desulfurization process (UAOD) to investigate the degradation of three sulfurous compounds in the synthetic gas condensate. Various parameters, including oxidizers (hydrogen peroxide, sodium peroxide, potassium superoxide), promoters (formic acid, acetic acid), catalysts (phosphotungstic acid, ferrous(II) sulfate, zirconium dioxide, vanadium pentoxide, aluminum oxide γ, copper(II) oxide), and phase transfer agents (isobutanol, tetraoctylammonium bromide, and tetra-n-butylammonium fluoride), were examined to identify the optimal combination for reducing sulfurous compounds in the UAOD process. The influence of the extraction stage and reactor vessel material on the desulfurization efficiency was also investigated. Results revealed that hydrogen peroxide, formic acid, phosphotungstic acid, and isobutyl alcohol were the most effective oxidizers, promoters, catalysts, and phase transfer agents, respectively. Response surface methodology was used to determine the optimal conditions by evaluating different concentrations of these reagents within specific ranges. The study considered ranges such as 10-70 vol % of hydrogen peroxide, 5-70 vol % of formic acid, 1-30 wt % of phosphotungstic acid, 1-30 vol % of isobutanol, and 5-40 min of ultrasonic ripple time. Empirical models were developed for each sulfurous compound type, providing optimal conditions for sulfur removal with an error margin of less than 0.1%. The validity of the suggested models was confirmed through an industrial data analysis. Additionally, it was observed that increasing the number of extraction stages improved desulfurization efficiency, and using a stainless-steel reactor vessel was more suitable than using a glass vessel.

Design and fabrication of bone tissue scaffolds based on PCL/PHBV containing hydroxyapatite nanoparticles: dual-leaching technique.

Scaffolds are the important part of the tissue-engineering field that are made from different biomaterials using various techniques. In this study, new scaffold based on polycaprolactone (PCL) and poly (hydroxybutyrate-co-hydroxyvalerate) (PHBV) containing hydroxyapatite nanopraticles (n-HA) were fabricated using the dual-leaching technique (DLT). Morphology, porosity, degradation rate, Fourier transfer infrared ray (FTIR) spectra, surface, and mechanical properties as well as capacity of cell binding and cell proliferation on the constructed scaffolds were evaluated. FTIR analysis showed that n-HA particles have some interest interactions with polymeric chains. The best 3D-structure was seen in PCL70PHBV30 scaffold using the scanning electron microscopy (SEM) and its structure improved in the presence of 3, 5 wt% of n-HA. Results of energy dispersive x-ray analysis (EDXA, map of Ca) showed that the nanoparticles have the uniform distribution within the fabricated scaffolds. Porosity analysis showed that the particulate salt leaching technique is a successful approach to building a 3D structure. Increasing of PHBV content and n-HA up to 3 and 5 wt% in the PCL matrix led to increase porosity in all samples. Mechanical properties analysis showed that values of compression modulus and strength are decreased with addition of PHBV and HA nanoparticles. These results were directly in line with the results of morphology and porosity. Cell culture experiments demonstrated that the PCL/PHBV/nHA nanocomposite scaffold has a better tendency of proliferation to cells than that of the pure PCL/PHBV scaffold. All of these results suggest promising potentials of the developed PCL/PHBV/nHA scaffolds in this study desire for bone tissue engineering.