The present study reports on a green method for the fabrication of wound dressing loaded with Pistacia atlantica extract. The oil was extracted from P. atlantica plant using a solvent extraction ...process. The UV–vis spectroscopy showed that the phenolic compounds existed in the P. atlantica oil (PAO). The result of the antioxidant activity with the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay illustrated an IC50 value of 7.26 mg/ml, which indicated that the PAO was a significant source of natural antioxidants. Then, the PAO-loaded polyvinyl alcohol (PVA)-sodium alginate (SA) nanofibres were successfully produced using the electrospinning process. The results of field emission scanning electron microscopy showed that the addition of the PAO to the polymer solution increased the diameter of the fabricated nanofibres, while the optimum blending concentration of the PAO for obtaining the maximum scaffold stiffness was almost 1.5% (w/v). The physical properties of the fabricated nanofibres were evaluated using Fourier transform infrared spectroscopy, X-ray diffraction technique, and thermogravimetric-derivative and thermogravimetric analysis. The results showed that the PAO was bonded to the structure of the PVA/SA nanofibres, and the crystallinity, as well as the thermal stability of the fabricated nanofibres increased due to this attachment. In addition, the experiments showed that the PAO concentration in the structure of the fabricated nanofibres played a major role in the drug release rate, and increasing the PAO concentration from the optimum value decreased the controlled release of the drug. Last, based on the two-film theory, a mass transfer model was developed to predict the PAO released from the fabricated wound dressing.
•The P. atlantica oil was extracted with high antioxidant and healing properties.•The nanofibers loaded oil extract with optimum concentration were electrospun.•P. atlantica extract acts as a natural cross-linker and strengthens the nanofibers.•The extract release followed the developed model of two-film mass transfer.
In this Paper,
YCa
2
Cu
3
O
7
superconductor composites were fabricated with biocompatible carbonate calcium nanoparticles. The effect of the biocompatible nanoparticle on YBCO superconductor ...properties were investigated. For this purpose, planetary ball milling process used to produce
CaCO
3
nanoparticles from cuttlebone (
Sepia pharaonis
) of the Persian Gulf. Then, samples of superconductor composite with the natural carbonate calcium were fabricated. The samples were prepared by solid state reaction method with mixing, calcination and sintering process. The samples were characterized and studied using dynamic light scattering technique, Meissner effect test, XRD analysis and FESEM imaging. The critical current density (
J
C
) and oxygen content of samples were measured by traditional four-probes method and iodometric titration method, respectively. The superconducting transition temperatures and
J
C
were determined 90.2 K and 28.4
A
/
cm
2
by four-probe method measurements, respectively. The results showed a significant enhancement of the superconducting
J
C
due to using the natural
CaCO
3
nanoparticles in the samples.
Hydrothermal liquefaction (HTL) is a green technology for biocrude production from algae. The global reaction kinetic, component additivity model (CAM), and response surface methodology (RSM) of HTL ...from high-lipid microalgae (Aurantiochytrium sp.) were evaluated. Lipids, proteins, and carbohydrates of the microalgae cell reacted at different rates and produced the aqueous phase, bio-oil, and gas phase in the kinetic model. Performing global kinetic modelling, understanding the reactions, and the performance of algae for biofuel production by HTL were the main ideas and novelty behind this work. Also, the predictive ability of bio-oil yield was examined by kinetic, CAM, and RSM approaches. MATLAB was utilized to solve the system of ordinary differential equations and calculate the optimum values for Arrhenius kinetic parameters by minimizing the least-square differences between model and experimental yields. R-squared of 0.997 showed that the global kinetic modelling provides a great prediction of bio-oil yields. Activation energies were calculated at 32.31, 38.50, and 46.99 kJ/mol for the conversion of lipids, proteins, and carbohydrates to bio-oil. Furthermore, a maximum bio-oil yield of 53.43 wt% was predicted at 800 K in 2 min. Also, the result of bio-oil prediction by global kinetic modelling compared to CAM and RSM equations. In comparison with the CAM model, the RSM equations showed better adaption with the bio-oil yield at 350 °C and 40 min. However, the kinetic model had the best potential for bio-oil predicting yields of Aurantiochytrium sp. because of the minimum mean absolute error of 2.078%.
Economic estimation of an environmental-friendly biomethanation process based on economic values of consumed and produced gases would be a unique attitude. In this paper, time and space dependent ...concentration profiles of components involved in a batch process, designed for biomethanation, were predicted through a mass transfer modelling. The reaction terms used in the modeling required bio-kinetic parameters of μ
max
, m, k
L
, Y
C/L
, Y
X/L
, and
Y
P/L
which were globally optimized via a predefined algorithm using some experimental data as 0.0987 day
1
, 0.1374 day
1
, 1.5422 mole m
−3
, 1.3636, 0.0183, 0.0908. Upon model verification, process income was calculated for a long-term scenario under a variety of factors and maximized through response surface methodology. The maximum income achieved was $-0.4/m
3
bioreactor. A term carbon subsidy was considered in the income equation in order to find a break-even income for subsidy value of $363/ton CO
2
. Sensitivity analysis revealed that the amount of carbon subsidy directly influenced the selection of low or high levels of some process parameters to make the process profitable. In addition, it was found that pressure and liquid volume were the most important factors to achieve maximum income when $30 and $300/ton CO
2
carbon subsidy were allocated to the process, respectively.
In this study, an experimental design was employed to optimize the fabrication of the
YCa
2
Cu
3
O
7
superconductor composite. The superconductors were fabricated using biocompatible calcium ...carbonate nanoparticles extracted from cuttlebone, Sepia pharaonis, of the Persian Gulf in the Bushehr coastal area, and their effects on
YCa
2
Cu
3
O
7
superconductor’s properties were investigated. Ball milling process and solid-state calcination reaction were used for obtaining the natural calcium carbonate nanoparticles and fabrication of the superconductors, respectively. The effects of three factors, milling time and the excess amount of the natural calcium carbonate as well as yttrium oxide, were investigated on the superconductivity properties of the products. The Taguchi statistical design of experiments was conducted to reveal the sensitivity analysis of the products’ properties due to the variation in each variable, finding optimal production conditions, and reduction in the total number of required experiments. In this method, the oxygen content of the fabricated superconductor was considered as the targeted
YCa
2
Cu
3
O
7
property. Moreover, the morphology and structural properties of the products were investigated to find the relationship between physicochemical properties and superconductivity. The
YCa
2
Cu
3
O
7
superconductors were characterized by the Meissner effect test, XRD analysis, and FESEM imaging. The sensitivity analysis was shown that by increasing milling time and the excess amount of the reactants in the solid-state reaction, the connectivity and crystallization of the grains were improved, and the optimum operating conditions for the production were achieved. Besides, the variation in milling time causes more signal-to-noise ratio, which indicates the highest efficacy of this factor on the superconductivity of the products in comparison with the other variables.
In the last two decades, researchers have attempted to use environmentally friendly pigments and porous nanostructures as sensitizers and semiconductors in dye-sensitized solar cells (DSSCs), ...respectively. In this study, the pigments were extracted from black plums (Syzygium cumini) to increase the biocompatibility of the DSSCs. The UV–vis spectroscopy of the extracted solution revealed the existence of anthocyanin pigments. The cyclic voltammetry measurement showed that the pigment energy levels were suitable for electron transfer to the TiO2 semiconductor, and the pigment electrochemical properties were also comparable with the commercial synthetic pigments. The dynamic light scattering experiment and zeta potential measurement illustrated that the size and electrostatic potential of the pigments were 0.3 nm and ±5 mV, respectively. These data confirmed the potential of the pigments for the diffusion into the porous structure of the TiO2 semiconductor and attraction as a shell layer on its surfaces. Besides, the TiO2 pastes were produced with seven different methods and characterized using XRD, SEM, and BET experiments. The results showed that the morphology, particle size, porosity, and surface area of the produced nanostructures were different in each method. Finally, the pastes were coated on the glass, sensitized with the extracted natural pigments, and used in the fabricated DSSCs. The efficiency of the cells was evaluated in the range of 0.027%–0.256% using the sun simulator technique. The results showed that the optimum particle size of the TiO2 semiconductor was around 25.6 nm which had been formed in the sixth method of the paste preparation.
Biomass (especially algae) is a renewable energy source that can be a great alternative to fossil fuels. Wet algal biomass converts into products such as solid, aqueous, and gaseous phases as well as ...biocrude in hydrothermal liquefaction (HTL). The aim of this work was to provide detailed exergy analyses of the production of biocrude from
Nannochloropsis
sp. by HTL. Physical and chemical exergy of the HTL products, exergy losses, exergy efficiency, and exergy distribution of the HTL process were determined in this research. The highest exergy loss and the lowest efficiency values obtained for the heat exchanger were 65,856.83 MJ/hr and 66.64%, respectively, which was mainly caused by the irreversibility of the heat transfer process. Moreover, the HTL reactor had high efficiency (99.9%) due to the complex reactions that occurred at high temperature and pressure. Also, the optimum operating conditions of the reactor were obtained at 350 °C and 20 MPa by using sensitivity analysis. The high overall exergy efficiency of the process (94.93%) indicated that HTL was the most effective process for the conversion of algae. In addition, the exergy recovery values of the overall exergy input values in the HTL process for biocrude, as well as the aqueous, solid, and gas phases, were nearly 74.88%, 18.42%, 0.86%, and 0.76%, respectively. Exergy assessment provides beneficial information for improving the thermodynamic performance of the HTL system.
Injection of chemicals in the reservoir in order to displace the remaining oil from the pore spaces is among the most widely accepted techniques. Combination of surfactant and polymer along with ...nanoparticles (NPs) is gaining the attention of scholars nowadays. Present work focuses on the application of bio-Ca NPs with the surfactant polymer (SP) slug to improve its efficiency. Surface tension, interfacial tension, surfactant adsorption and oil recovery were examined for the evaluation of performance of the NPs-assisted SP injection technique. Addition of 1000 ppm of NPs reduced the CMC of surfactant by 24%. Synergistic effect between bio-Ca NPs and anionic surfactant molecules observed from the experimental results of surface tension and IFT values. The surface tension value of distilled water reduces to 34.5 mN from 72.6 mN/m upon addition of 2500 ppm surfactant. Addition of NPs further reduced the surface tension of the solution by 24%. Introduction of NPs modified the wetting behavior of oil-wet surface to strongly water-wet surface. Furthermore, addition of NPs also improved the viscosity of the SP slug by 41% at 108 s
−1
shear rate. An increase in cumulative oil recovery from ~ 69 to ~ 76% was obtained upon addition of 1000 ppm of bio-Ca NPs in SP slug. Furthermore, 1000 ppm of NPs addition also reduced the surfactant adsorption by 33% for 1000 ppm of surfactant concentration. It can be inferred from the experimental data that the bio-Ca NPs has the potential to improve the performance of the chemical injection technique that can be exploited for additional oil recovery.
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Biological treatment, due to the formation of hazardous chemicals to remove organic compounds such as dimethyl sulfoxide (DMSO) and N, N-dimethylacetamide (DMAC), has limited ...potential. Advanced oxidation processes (AOPs) are regarded as a viable alternative for treating molecules containing carbon-hydrogen bonds that cannot be broken down by traditional physico-chemical methods. In this investigation, various AOPs such as Photo-Fenton, Electro-Fenton, and Photo-Electro-Fenton processes were studied to treat wastewaters containing DMSO and DMAC. The effects of the operating parameters, including various initial concentrations of DMSO and DMAC, initial pH, reaction time, different concentrations of Fenton’s reagent, power of UV lamp, different concentrations of electrolytes, the distance between electrodes and current intensity, were investigated. The findings of the experiments revealed that a pH of 3 and a reaction time of 120 min were optimal. At 2000 mg L−1 of DMSO, maximum degradation and the final concentration of TOC were 98.64 % and 256.8 mg L−1, respectively, by the Electro-Fenton process under the optimal conditions. The Electro-Fenton process was successful in determining the maximum degradation of DMAC (96.31 %) and the final TOC concentration (10.03 mg L−1) at 250 mg L−1 of DMAC under optimal conditions. Finally, it can be concluded that the Electro-Fenton process was the best process for the efficient removal of DMSO and DMAC. The second step of the kinetic model follows a pseudo-first-order reaction for 250 and 500 mg L−1 of pollutants and obeyed a pseudo-second-order kinetic model for concentrations of 1000, 2000 mg L−1.
CO
2
miscible injection method combined with surfactants and silica nanoparticles was studied to investigate the effect of these additives on CO
2
mass transfer parameters to the light oil, including ...diffusion coefficient, mass transfer coefficient and solubility. Silica nanoparticles with controlled size distribution were synthesized in isooctane/1-hexanol/CTAB/ammonium hydroxide, a highly-stable reverse micellar system with w
o
=5. The presence of Si-O-Si and Si-O-H bonds in FTIR spectra of the system revealed that silica nanoparticles are formed by partial hydrolysis of TEOS. Results of DLS indicated that the average size and size distribution of the synthesized nanoparticles were 27.6 nm and 13-76 nm, respectively. Diffusion tests were carried out using CO
2
gas and three liquid systems: isooctane/1-hexanol, isooctane/1-hexanol/CTAB reverse micellar system without nanoparticles, and isooctane/1-hexanol/CTAB reverse micellar system with nanoparticles. Results of modeling and optimization of the gas-liquid systems under nonequilibrium interface condition, using pressure decay data show that the presence of surfactants and nanoparticles leads to decreased gas diffusion coefficient; while increased interface mass transfer resistance due to presence of aqueous droplets and nanoparticles as well as lower solubility of CO
2
in the light oil are the results of applying these additives, which limits their application. The obtained CO
2
diffusion coefficients for isooctane/1-hexanol, reverse micellar system without nanoparticles, and reverse micellar system with nanoparticles are 8.5550×10
−8
, 8.2216×10
−8
, and 8.1114×10
−8
m
2
/s, respectively.
