leila Ardestani; Morteza Hosseini; Mohsen Jahanshahi; Alireza Amiri
Abstract
The bioactive compounds in extracts are prone to degradation by oxidation, heat, or light. Nanoencapsulation is one of the best techniques to keep the properties of these chemical compounds. The aim of this study was the extraction of Melissa officinalis (MO) and nanoencapsulation of the extract via ...
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The bioactive compounds in extracts are prone to degradation by oxidation, heat, or light. Nanoencapsulation is one of the best techniques to keep the properties of these chemical compounds. The aim of this study was the extraction of Melissa officinalis (MO) and nanoencapsulation of the extract via chitosan as a biodegradable polymer. In this research, extraction of MO was investigated using various extraction methods and nanoencapsulation with MO extract was carried out via ionic gelation technique. The effectiveness of the extracts was evaluated by measuring the total phenolic content (TPC), antioxidant activity, and extraction efficiency of the solid contents. The highest efficiency was achieved for microwave-assisted extraction with the utmost values in each parameter. (TSC) was 22.81% and amounts of the TPC and antioxidant activity were 311.94 mg Gallic acid and 36 mg diphenyl picryl hydrazyl (DPPH) per 1g of the plant, respectively. Morphology study by field emission scanning electron microscopy (FE-SEM) indicated spherical shape nanoparticles with a diameter of 25nm. The size of the nanoparticles was evaluated by the Dynamic Light Scattering (DLS) technique for various concentrations of the used extracts in the encapsulation process. For 1.0, 3.0, and 5.0 mg /mL concentration, mean diameters were 24, 118, and 145 nm, respectively. Results indicated that microwave-assisted extraction was the best extraction method for MO and the encapsulation of MO extract could be created successfully with different particle sizes for the protection of bioactive compounds. Since MO is a beneficial herbal plant, the development of this research is recommended.
Soodabeh Khalili; Mohsen Jahanshahi
Abstract
The objective of this work is to develop a cost-effective carbonaceous CO2 adsorbent. N-doped porous carbon (NDC) with nano- pore size was synthesized by KOH activation of nano polyaniline (PANI). PANI synthesized in this work has thin nanofibrillar morphology with different lengths and diameters. The ...
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The objective of this work is to develop a cost-effective carbonaceous CO2 adsorbent. N-doped porous carbon (NDC) with nano- pore size was synthesized by KOH activation of nano polyaniline (PANI). PANI synthesized in this work has thin nanofibrillar morphology with different lengths and diameters. The activation process was carried out at 800 °C with KOH/precursor ratio of 2. This adsorbent of carbon exhibits high CO2 adsorption capacity of 1.9 mmol/g at 25 °C under atmospheric pressure. The morphology of PNCs is investigated through different technical methods, such as scanning electron microscopy (SEM), N2 adsorption isotherm at 77 K and Fourier transform infrared spectroscopy (FTIR). The CO2 adsorption experiments were done at three different temperatures (298, 308, and 318 K) and pressures up to 10 bar, and correlated with the Langmuir, Freundlich, and Sips models. The Sips isotherm model presented the best fit to the experimental data. Small values of isosteric heat of adsorption were evaluated based on Clausius–Clapeyron equation showed the physical nature of adsorption mechanism. The high amount of CO2 capture by nano- pore size NDC renders it as a promising carrier for practical applications such as gas separation.
Mahzad Mirzaei; Reza Khanbabaie; Mohsen Jahanshahi; Ghasem Najafpour Darzi
Abstract
Recently, safety concerns over the handling of nanomaterials have become an important issue. The aim of the present study was to optimize the key parameters in the hydrothermal synthesis of CuInS2 quantum dots (QDs) as a non-toxic alternative to the cadmium-based QDs, that historically had dominated ...
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Recently, safety concerns over the handling of nanomaterials have become an important issue. The aim of the present study was to optimize the key parameters in the hydrothermal synthesis of CuInS2 quantum dots (QDs) as a non-toxic alternative to the cadmium-based QDs, that historically had dominated the literature. Response surface methodology (RSM) in combination with D-optimal design was applied to optimize the synthesis and evaluate the PL intensity as the response which described by a reduced quadratic equation. The relationship between the PL intensity and independent variables (ligand/precursor, reaction time, reaction temperature, pH, and precursors ratio) was investigated using reduced quadratic polynomial equations. The produced QDs in the optimum condition were analyzed by UV-Vis, FE-SEM, and FTIR. The results showed that the nanoparticles have a high PL intensity and a red shift in both emission and absorbtion spectra which is a splendid point for their applications specially in bioimaging. The interaction between variables was not significant and the temperature was the most effective variable of PL intensity. A good agreement between predicted model and experimental data confirmed the correlated model.
Nika Gholamzadeh; Majid Peyravi; Mohsen Jahanshahi
Abstract
The olive mill wastewater (OMW) is generated from olive oil extraction in olive mills. It contains a very high organic load and considerable quantities of phytotoxicity compounds. Comprehensive articles with different methods have been published about the treatment of OMW. This paper reviews the recent ...
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The olive mill wastewater (OMW) is generated from olive oil extraction in olive mills. It contains a very high organic load and considerable quantities of phytotoxicity compounds. Comprehensive articles with different methods have been published about the treatment of OMW. This paper reviews the recent reports on the variety methods of OMW treatment. Biological process, containing aerobic pre-treatment by using different cultures and anaerobic co-digestion with other sewage and also added external nutrient with optimum ratio attracted much attention in the treatment of OMW. However, advanced oxidation process (AOP) due to the high oxidation potential which causes destruction of organic pollutants, toxic and chlorinated compounds have been considered. Furthermore, membrane technologies consist of microfiltration, ultrafiltration and especially nanofiltrationin wastewater treatment are growing in recent years. They offer high efficiency and mediocre investments owing to novel membrane materials, membrane design technics, module figures and improvement of the skills. In addition, fouling reduces the membrane performances in time, which is a main problem of cost efficiency.