Search results for: supercritical methanol

Authors: Kyunghun Kang, Sangwoo Oh, Yongha Hwang

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PDMS (Polydimethylsiloxane)-based microfluidic device has been recently applied to area of biomedical research, tissue engineering, and diagnostics because PDMS is low cost, nontoxic, optically transparent, gas-permeable, and especially biocompatible. Generally, PDMS microfluidic devices are fabricated by conventional soft lithography. Microfabrication requires expensive cleanroom facilities and a lot of time; however, only two-dimensional or simple three-dimensional structures can be fabricated. In this study, we introduce fabricating method for complex three-dimensional microfluidic channels using soluble wax mold. Using the 3D printing technique, we firstly fabricated three-dimensional mold which consists of soluble wax material. The PDMS pre-polymer is cast around, followed by PDMS casting and curing. The three-dimensional casting mold was removed from PDMS by chemically dissolved with methanol and acetone. In this work, two preliminary experiments were carried out. Firstly, the solubility of several waxes was tested using various solvents, such as acetone, methanol, hexane, and IPA. We found the combination between wax and solvent which dissolves the wax. Next, side effects of the solvent were investigated during the curing process of PDMS pre-polymer. While some solvents let PDMS drastically swell, methanol and acetone let PDMS swell only 2% and 6%, respectively. Thus, methanol and acetone can be used to dissolve wax in PDMS without any serious impact. Based on the preliminary tests, three-dimensional PDMS microfluidic channels was fabricated using the mold which was printed out using 3D printer. With the proposed fabricating technique, PDMS-based microfluidic devices have advantages of fast prototyping, low cost, optically transparence, as well as having complex three-dimensional geometry. Acknowledgements: This research was supported by Supported by a Korea University Grant and Basic Science Research Program through the National Research Foundation of Korea(NRF).

Keywords: microfluidic channel, polydimethylsiloxane, 3D printing, casting

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Authors: Rawaz A. Ahmed, Katherine Huddersman

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High-lipid Fats, Oils and Grease (FOGs) from wastewater are underutilized despite their potential for conversion into valuable fuels; this work describes a surface-functionalized fibrous Polyacrylonitrile (PAN) mesh as a novel heterogeneous acid catalyst for the conversion of free fatty acids (FFAs), via a catalytic esterification process into biodiesel. The esterification of stearic acid (SA) with methanol was studied over an acidified PAN solid acid catalyst. Disappearance of the carboxylic acid (C=O) peak of the stearic acid at 1696 cm-1 in the FT-IR spectrum with the associated appearance of the ester (C=O) peak at 1739 cm-1 confirmed the production of the methyl stearate. This was further supported by 1H NMR spectra with the appearance of the ester (-CH₂OCOR) at 3.60-3.70 ppm. Quantitate analysis by GC-FID showed the catalyst has excellent activity with >95 % yield of methyl stearate (MS) at 90 ◦C after 3 h and a molar ratio of methanol to SA of 35:1. To date, to our best knowledge, there is no research in the literature on the esterification reaction for biodiesel production using a modified PAN mesh as a catalyst. It is noteworthy that this acidified PAN mesh catalyst showed comparable activity to conventional Brönsted acids, namely H₂SO₄ and p-TSA, as well as exhibiting higher activity than various other heterogeneous catalysts such as zeolites, ion-exchange resins and acid clay.

Keywords: fats oil and greases (FOGs), free fatty acid, esterification reaction, methyl ester, PAN

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Authors: Ikechukwu Ejim

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This research project addresses the optimization of biodiesel production from gossypium herbaceum (cottonseed) and moringa oleifera seeds. Soxhlet extractor method using n-hexane for gossypium herbaceum (cottonseed) and ethanol for moringa oleifera were used for solvent extraction. 1250 ml of oil was realized from both gossypium herbaceum (cottonseed) and moringa oleifera seeds before characterization. In transesterification process, a 4-factor-3-level experiment was conducted using an optimal design of Response Surface Methodology. The effects of methanol/oil molar ratio, catalyst concentration (%), temperature (°C) and time (mins), on the yield of methyl ester for both cottonseed and moringa oleifera oils were determined. The design consisted of 25 experimental runs (5 lack of fit points, five replicate points, 0 additional center points and I optimality) and provided sufficient information to fit a second-degree polynomial model. The experimental results suggested that optimum conditions were as follows; cottonseed yield (96.231%), catalyst concentration (0.972%), temperature (55oC), time (60mins) and methanol/oil molar ratios (8/1) respectively while moringa oleifera optimum values were yield (80.811%), catalyst concentration (1.0%), temperature (54.7oC), time (30mins ) and methanol/oil molar ratios (8/1) respectively. This optimized conditions were validated with the actual biodiesel yield in experimental trials and literature.

Keywords: optimization, Gossypium herbaceum, Moringa oleifera, biodiesel

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Authors: V. Mani Rathnam, Giridhar Madras

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Fossil fuels are depleting rapidly as the demand for energy, and its allied chemicals are continuously increasing in the modern world. Therefore, sustainable renewable energy sources based on non-edible oils are being explored as a viable option as they do not compete with the food commodities. Oils such as castor oil are rich in fatty acids and thus can be used for the synthesis of biodiesel, bio-lubricants, and many other fine industrial chemicals. There are several processes available for the synthesis of different chemicals obtained from the castor oil. One such process is the transesterification of castor oil, which results in a mixture of fatty acid methyl esters. The main products in the above reaction are methyl ricinoleate and methyl 10-undecenoate. To separate these compounds, supercritical carbon dioxide (SCCO₂) was used as a green solvent. SCCO₂ was chosen as a solvent due to its easy availability, non-toxic, non-flammable, and low cost. In order to design any separation process, the preliminary requirement is the solubility or phase equilibrium data. Therefore, the solubility of a mixture of methyl ricinoleate with methyl 10-undecenoate in SCCO₂ was determined in the present study. The temperature and pressure range selected for the investigation were T = 313 K to 333 K and P = 10 MPa to 18 MPa. It was observed that the solubility (mol·mol⁻¹) of methyl 10-undecenoate varied from 2.44 x 10⁻³ to 8.42 x 10⁻³ whereas it varied from 0.203 x 10⁻³ to 6.28 x 10⁻³ for methyl ricinoleate within the chosen operating conditions. These solubilities followed a retrograde behavior (characterized by the decrease in the solubility values with the increase in temperature) throughout the range of investigated operating conditions. An association theory model, coupled with regular solution theory for activity coefficients, was developed in the present study. The deviation from the experimental data using this model can be quantified using the average absolute relative deviation (AARD). The AARD% for the present compounds is 4.69 and 8.08 for methyl 10-undecenoate and methyl ricinoleate, respectively in a mixture of methyl ricinoleate and methyl 10-undecenoate. The maximum solubility enhancement of 32% was observed for the methyl ricinoleate in a mixture of methyl ricinoleate and methyl 10-undecenoate. The highest selectivity of SCCO₂ was observed to be 12 for methyl 10-undecenoate in a mixture of methyl ricinoleate and methyl 10-undecenoate.

Keywords: association theory, liquid mixtures, solubilities, supercritical carbon dioxide

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Authors: Elitsa Kolentsova, Dimitar Dimitrov, Vasko Idakiev, Tatyana Tabakova, Krasimir Ivanov

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Formaldehyde production by selective oxidation of methanol is an important industrial process. The main by-products in the waste gas are CO and dimethyl ether (DME). The idea of this study is to combine the advantages of both Cu-Mn and Cu-Co catalytic systems by obtaining a new mixed Cu-Mn-Co catalyst with high activity and selectivity at the simultaneous oxidation of CO, methanol, and DME. Two basic Cu-Mn samples with high activity were selected for further investigation: (i) manganese-rich Cu-Mn/γ–Al2O3 catalyst with Cu/Mn molar ratio 1:5 and (ii) copper-rich Cu-Mn/γ-Al2O3 catalyst with Cu/Mn molar ratio 2:1. Manganese in these samples was replaced by cobalt in the whole concentration region, and catalytic properties were determined. The results show a general trend of decreasing the activity toward DME oxidation and increasing the activity toward CO and methanol oxidation with the increase of cobalt up to 60% for both groups of catalyst. This general trend, however, contains specific features, depending on the composition of the catalyst and the nature of the oxidized gas. The catalytic activity of the sample with Cu/(Mn+Co) molar ratio of 2:1 is gradually changed with increasing the cobalt content. The activity of the sample with Cu/(Mn+Co) molar ratio of 1: 5 passes through a maximum at 60% manganese replacement by cobalt, probably due to the formation of highly dispersed Co-based spinel structures (Co3O4 and/or MnCo2O4). In conclusion, the present study demonstrates that the Cu-Mn-Co/γ–alumina supported catalysts have enhanced activity toward CO, methanol and DME oxidation. Cu/(Mn+Co) molar ratio 1:5 and Co/Mn molar ratio 1.5 in the active component can ensure successful oxidation of CO, CH3OH and DME. The active component of the mixed Cu-Mn-Co/γ–alumina catalysts consists of at least six compounds - CuO, Co3O4, MnO2, Cu1.5Mn1.5O4, MnCo2O4 and CuCo2O4, depending on the Cu/Mn/Co molar ratio. Chemical composition strongly influences catalytic properties, this effect being quite variable with regards to the different processes.

Keywords: Cu-Mn-Co catalysts, oxidation, carbon oxide, VOCs

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Authors: Chiu-Hsuan Lee, Min-Hao Yuan, Kun-Cheng Lin, Qiao-Yin Tsai, Yun-Jie Lu, Yi-Jhen Wang, Hsin-Yi Lin, Chih-Hua Hsu, Jia-Rong Jhou, Si-Ying Li, Yi-Hung Chen, Je-Lueng Shie

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Raw food waste has a high-water content. If it is incinerated, it will increase the cost of treatment. Therefore, composting or energy is usually used. There are mature technologies for composting food waste. Odor, wastewater, and other problems are serious, but the output of compost products is limited. And bakelite is mainly used in the manufacturing of integrated circuit boards. It is hard to directly recycle and reuse due to its hard structure and also difficult to incinerate and produce air pollutants due to incomplete incineration. In this study, supercritical hydrothermal and subcritical glycolysis thermal conversion technology is used to convert biomass wastes of bakelite and raw kitchen wastes to carbon materials and biofuels. Batch carbonization tests are performed under high temperature and pressure conditions of solvents and different operating conditions, including wet and dry base mixed biomass. This study can be divided into two parts. In the first part, bakelite waste is performed as dry-based industrial waste. And in the second part, raw kitchen wastes (lemon, banana, watermelon, and pineapple peel) are used as wet-based biomass ones. The parameters include reaction temperature, reaction time, mass-to-solvent ratio, and volume filling rates. The yield, conversion, and recovery rates of products (solid, gas, and liquid) are evaluated and discussed. The results explore the benefits of synergistic effects in thermal glycolysis dehydration and carbonization on the yield and recovery rate of solid products. The purpose is to obtain the optimum operating conditions. This technology is a biomass-negative carbon technology (BNCT); if it is combined with carbon capture and storage (BECCS), it can provide a new direction for 2050 net zero carbon dioxide emissions (NZCDE).

Keywords: biochar, raw food waste, bakelite, supercritical hydrothermal, subcritical glycolysis, biofuels

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Authors: Rauf Razzaq, Kaiwu Dong, Muhammad Sharif, Ralf Jackstell, Matthias Beller

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Carbon dioxide (CO2), a key greenhouse gas produced from both anthropogenic and natural sources, has been recently considered to be an important C1 building-block for the synthesis of many industrial fuels and chemicals. Catalytic hydrogenation of CO2 using a heterogeneous system is regarded as an efficient process for CO2 valorization. In this regard CO2 reduction to CO via the reverse water gas shift reaction (RWGSR) has attracted much attention as a viable process for large scale commercial CO2 utilization. This process can generate syn-gas (CO+H2) which can provide an alternative route to direct CO2 conversion to methanol and/or liquid HCs from FT reaction. Herein, we report a highly active and selective silica supported copper catalyst with efficient CO2 reduction to CO in a slurry-bed batch autoclave reactor. The reactions were carried out at 200°C and 60 bar initial pressure with CO2/H2 ratio of 1:3 with varying temperature, pressure and fed-gas ratio. The gaseous phase products were analyzed using FID while the liquid products were analyzed by using FID detectors. It was found that Cu/SiO2 catalyst prepared using novel ammonia precipitation-urea gelation method achieved 26% CO2 conversion with a CO and methanol selectivity of 98 and 2% respectively. The high catalytic activity could be attributed to its strong metal-support interaction with highly dispersed and stabilized Cu+ species active for RWGSR. So, it can be concluded that reduction of CO2 to CO via RWGSR could address the problem of using CO2 gas in C1 chemistry.

Keywords: CO2 reduction, methanol, slurry reactor, synthesis gas

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Authors: Golnoosh Torabian, P. Valtchev, F. Dehghani

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The need for efficient nutraceutical products has been dramatically changing the approach of the industrial processes. The development of novel mild processes is highly demanded for the production of such products; especially when both quality and safety need to be guaranteed during their long shelf life. Within this research, for the first time, we investigated the effect of supercritical carbon dioxide treatment for the inactivation of microbes and enzymes in a berry juice possessing therapeutic effect. We demonstrated that a complete inactivation of microbes can be achieved at optimized conditions of treatment. However, the bottle neck of the process was represented by the unpromising inactivation of the degradative enzyme by supercritical carbon dioxide treatment. However, complete enzyme inactivation was achieved by applying two strategies: the first was optimizing juicing method by adding a mechanical step and the second strategy was addition of natural inhibitors to the juice. Overall these results demonstrate that our hybrid process has a significant effect on the inactivation of microorganism and enzymes in the fresh juice. The developed process opens the possibility for the evolution of new products with optimal nutritional and sensorial characteristics, as well as offering a competitive cost and an environmentally friendly alternative for pasteurization and extension of shelf life in a wide range of natural therapeutic products.

Keywords: hybrid method, berry juice, pasteurization, enzymes inactivation

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Authors: Wanthani Paengsri, Thanyarat Chuesaard, Napapha Promsawan

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Spilanthes acmella Murr. was extracted with methanol, yielding methanol crude extract 5.86 %w/w. This study aimed to examine the chemical composition and antioxidant activity of methanolic crude extract. The chemical composition of methanolic crude extract was analyzed by gas chromatography-mass spectrometry (GC-MS). The predominant components were found to be palmitic acid (40.08%), 2-hexadecanoyl glycerol (6.96%) and octadecanoic acid (4.06%). Antioxidant activity was determined using 2,2-diphenyl-1-picryl hydrazyl (DPPH) free radical, for evaluating free radicle scavenging activity. The methanolic extract at 150 µg/mL showed an antioxidant activity with high of radical scavenging activity (75.23%).

Keywords: antioxidant activity, GC-MS analysis, Spilanthes, Phak-Kratt Hauwaen

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Authors: Sarmistha Baruah, Akshai Kumar, Nageswara Rao Peela

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The global energy crisis due to the dependence on fossil fuels and its limited reserves as well as environmental pollution are key concerns to the research communities. However, the implementation of alcohol-based fuel cells such as methanol is anticipated as a reliable source of future energy technology due to their high energy density, environment friendliness, ease of storage, transportation, etc. To drive the anodic methanol oxidation reaction (MOR) in direct methanol fuel cells (DMFCs), an active and long-lasting catalyst is necessary for efficient energy conversion from methanol. Recently, transition metal-zeolite-based materials have been considered versatile catalysts for a variety of industrial and lab-scale processes. Large specific surface area, well-organized micropores, and adjustable acidity/basicity are characteristics of zeolites that make them excellent supports for immobilizing small-sized and highly dispersed metal species. Significant advancement in the production and characterization of well-defined metal clusters encapsulated within zeolite matrix has substantially expanded the library of materials available, and consequently, their catalytic efficacy. In this context, we developed bimetallic Ni-Co catalysts encapsulated within LTA (also known as 4A) zeolite via a method combined with the in-situ encapsulation of metal species using hydrothermal treatment followed by a chemical reduction process. The prepared catalyst was characterized using advanced characterization techniques, such as X-ray diffraction (XRD), field emission transmission electron microscope (FETEM), field emission scanning electron microscope (FESEM), energy dispersive X-ray (EDX), and X-ray photoelectron spectroscopy (XPS). The electrocatalytic activity of the catalyst for MOR was carried out in an alkaline medium at room temperature using techniques such as cyclic voltammetry (CV), and chronoamperometry (CA). The resulting catalyst exhibited better catalytic activity of 12.1 mA cm-2 at 1.12 V vs Ag/AgCl and retained remarkable stability (~77%) even after 1000 cycles CV test for the electro-oxidation of methanol in alkaline media without any significant microstructural changes. The high surface area, better Ni-Co species integration in the zeolite, and the ample amount of surface hydroxyl groups contribute to highly dispersed active sites and quick analyte diffusion, which provide notable MOR kinetics. Thus, this study will open up new possibilities to develop a noble metal-free zeolite-based electrocatalyst due to its simple synthesis steps, large-scale fabrication, improved stability, and efficient activity for DMFC application.

Keywords: alkaline media, bimetallic, encapsulation, methanol oxidation reaction, LTA zeolite.

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Authors: Akwu N. A., Naidoo Y., Salau V. F., Olofinsan K. A.

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Grewia lasiocarpa E. Mey. ex Harv. (Malvaceae) is a Southern African medicinal plant indigenously used with other plants for birthing problems. The anti-diabetic properties of the hexane, chloroform, and methanol extracts of Grewia lasiocarpa stem bark were assessed using in vitro α-glucosidase enzyme inhibition assay. The predictive in silico drug-likeness and toxicity properties of the phytocompounds were conducted using the pKCSM, ADMElab, and SwissADME computer-aided online tools. The highest α-glucosidase percentage inhibition was observed in the hexane extract (86.76%, IC50= 0.24 mg/mL), followed by chloroform (63.08%, IC50= 4.87 mg/mL) and methanol (53.22%, IC50= 9.41 mg/mL); while acarbose, the standard anti-diabetic drug was (84.54%, IC50= 1.96 mg/mL). The α-glucosidase assay revealed that the hexane extract exhibited the strongest carbohydrate inhibiting capacity and is a better inhibitor than the standard reference drug-acarbose. The computational studies also affirm the results observed in the in vitroα-glucosidaseassay. Thus, the extracts of G. lasiocarpa may be considered a potential plant-sourced compound for treating type 2 diabetes mellitus. This is the first study on the anti-diabetic properties of Grewia lasiocarpa hexane, chloroform, and methanol extracts using in vitro and in silico models.

Keywords: grewia lasiocarpa, α-glucosidase inhibition, anti-diabetes, ADMET

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Authors: Wael A. Aboutaleb, Ahmed M. A. El Naggar, Heba M. Gobara

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This research work reports the photocatalytic production of hydrogen from water-methanol mixture using three different 15% ceria/iron oxide catalysts. The catalysts were prepared by physical mixing, precipitation, and ultrasonication methods and labeled as catalysts A-C. The structural and texture properties of the obtained catalysts were confirmed by X-ray diffraction (XRD), BET-surface area analysis and transmission electron microscopy (TEM). The photocatalytic activity of the three catalysts towards hydrogen generation was then tested. Promising hydrogen productivity was obtained by the three catalysts however different gases compositions were obtained by each type of catalyst. Specifically, catalyst A had produced hydrogen mixed with CO₂ while the composite structure (catalyst B) had generated only pure H₂. In the case of catalyst C, syngas made of H₂ and CO was revealed, as a novel product, for the first time, in such process.

Keywords: hydrogen production, water splitting, photocatalysts, clean energy

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Authors: C. N. Okafor, M. Maaza, T. A. E. Mokrani

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A proton exchange membrane has been developed for Direct Methanol Fuel Cell (DMFC). The nanofiber network composite membranes were prepared by interconnected network of Nafion (perfuorosulfonic acid) nanofibers that have been embedded in an uncharged and inert polymer matrix, by electro-spinning. The spinning solution of Nafion with a low concentration (1 wt. % compared to Nafion) of high molecular weight poly(ethylene oxide), as a carrier polymer. The interconnected network of Nafion nanofibers with average fiber diameter in the range of 160-700nm, were used to make the membranes, with the nanofiber occupying up to 85% of the membrane volume. The matrix polymer was cross-linked with Norland Optical Adhesive 63 under UV. The resulting membranes showed proton conductivity of 0.10 S/cm at 25°C and 80% RH; and methanol permeability of 3.6 x 10-6 cm2/s.

Keywords: composite membrane, electrospinning, fuel cell, nanofibers

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Authors: Michal Urzynicok, Krzysztof Kwiecinski

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The development of materials used in the power generation industry for the production of boilers and their parts is characterized by high steam parameters, which present new challenges. Implementation of new combinations of alloying elements that lead to the best possible mechanical properties, including creep resistance, greatly affects new steels' weldability. All new grades have to undergo many different examinations, in regards to bending and welding, in order to enable the development of fabrication technologies, ensuring failure-free production and assembly of boiler components. 12% Cr martensitic steels like THOR™ 115 or VM-12 SHC are characterized by high oxidation resistance in high-temperature environments. At the moment, VM-12 SHC can be found in many boilers where both headers and superheater coils were produced. As this material is very difficult to obtain, a search for a proper replacement has begun. A new creep strength-enhanced ferritic steel for service in supercritical and ultra-supercritical boiler applications was developed by Tenaris in Italy and it is designated as Thor™115 (Tenaris High Oxidation Resistance). As high demand in power plants occurred to replace some parts of existing installations fabricated from VM12-SHC with other alternatives, a new development of welding procedures has begun to prepare fabricators for the challenges of joining old components with new THOR™ 115 material. This paper covers the first research of welding of dissimilar joints made out of VM12-SHC and THOR™ 115.

Keywords: thor, vm12, dissimilar welding, weldability

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Authors: Andreas Kohlhepp, Gerrit Schatte, Wieland Christoph, Spliethoff Hartmut

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In recent years the research of heat transfer phenomena of water and other working fluids near the critical point experiences a growing interest for power engineering applications. To match the highly volatile characteristics of renewable energies, conventional power plants need to shift towards flexible operation. This requires speeding up the load change dynamics of steam generators and their heating surfaces near the critical point. In dynamic load transients, both a high heat flux with an unfavorable ratio to the mass flux and a high difference in fluid and wall temperatures, may cause problems. It may lead to deteriorated heat transfer (at supercritical pressures), dry-out or departure from nucleate boiling (at subcritical pressures), all cases leading to an extensive rise of temperatures. For relevant technical applications, the heat transfer coefficients need to be predicted correctly in case of transient scenarios to prevent damage to the heated surfaces (membrane walls, tube bundles or fuel rods). In transient processes, the state of the art method of calculating the heat transfer coefficients is using a multitude of different steady-state correlations for the momentarily existing local parameters for each time step. This approach does not necessarily reflect the different cases that may lead to a significant variation of the heat transfer coefficients and shows gaps in the individual ranges of validity. An algorithm was implemented to calculate the transient behavior of steam generators during load changes. It is used to assess existing correlations for transient heat transfer calculations. It is also desirable to validate the calculation using experimental data. By the use of a new full-scale supercritical thermo-hydraulic test rig, experimental data is obtained to describe the transient phenomena under dynamic boundary conditions as mentioned above and to serve for validation of transient steam generator calculations. Aiming to improve correlations for the prediction of the onset of deteriorated heat transfer in both, stationary and transient cases the test rig was specially designed for this task. It is a closed loop design with a directly electrically heated evaporation tube, the total heating power of the evaporator tube and the preheater is 1MW. To allow a big range of parameters, including supercritical pressures, the maximum pressure rating is 380 bar. The measurements contain the most important extrinsic thermo-hydraulic parameters. Moreover, a high geometric resolution allows to accurately predict the local heat transfer coefficients and fluid enthalpies.

Keywords: departure from nucleate boiling, deteriorated heat transfer, dryout, supercritical working fluid, transient operation of steam generators

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Authors: Kanika Kalra, Harmeet Kaur, Dinesh Goyal

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Total phenolics were extracted from waste orange peels by solvent extraction and alkali hydrolysis method. The most efficient solvents for extracting phenolic compounds from waste biomass were methanol (60%) > dimethyl sulfoxide > ethanol (60%) > distilled water. The extraction yields were significantly impacted by solvents (ethanol, methanol, and dimethyl sulfoxide) due to varying polarity and concentrations. Extraction of phenolics using 60% methanol yielded the highest phenolics (in terms of gallic acid equivalent (GAE) per gram of biomass) in orange peels. Alkali hydrolyzed extract from orange peels contained 7.58±0.33 mg GAE g⁻¹. By using the solvent extraction technique, it was observed that 60% methanol is comparatively the best-suited solvent for extracting polyphenolic compounds and gave the maximum yield of 4.68 ± 0.47 mg GAE g⁻¹ in orange peel extracts. DPPH radical scavenging activity and reducing the power of orange peel extract were checked, where 60% methanolic extract showed the highest antioxidant activity, 85.50±0.009% for DPPH, and dimethyl sulfoxide (DMSO) extract gave the highest yield of 1.75±0.01% for reducing power ability of the orange peels extract. Characterization of the polyphenolic compounds was done by using Fourier transformation infrared (FTIR) spectroscopy. Solvent and alkali hydrolysed extracts were evaluated for antibacterial activity using the agar well diffusion method against Gram-positive Bacillus subtilis MTCC441 and Gram-negative Escherichia coli MTCC729. Methanolic extract at 300µl concentration showed an inhibition zone of around 16.33±0.47 mm against Bacillus subtilis, whereas, for Escherichia coli, it was comparatively less. Broth-based turbidimetric assay revealed the antibacterial effect of different volumes of orange peel extracts against both organisms.

Keywords: orange peels, total phenolic content, antioxidant, antibacterial

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Authors: A. Mohammad Abdul Motalib Momin, B. Sheikh Mohammad Adil Uddin, C. Md Mamunur Rashid, D. Sheikh Arman Mahbub, E. Mohammad Sazzad Rahman, F. Abdullah Faruque

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The present study was designed to investigate the antioxidant and cytotoxicity potential of methanol and pet ether extracts of the Lagenaria siceraria (LM, LP), Cucumis sativus (CSM, CSP), Cucurbita maxima (CMM, CMP) plants. For the phytochemical screening, crude extract was tested for the presence of different chemical groups. In Lagenaria siceraria the following groups were identified: alkaloids, steroids, glycosides and saponins for methanol extract and alkaloids, steroids, glycosides, tannins and saponins are for pet ether extract. Glycosides, steroids, alkaloids, saponins and tannins are present in the methanol extract of Cucumis sativus; the pet ether extract has the alkaloids, steroids and saponins. Glycosides, steroids, alkaloids, saponins and tannins are present in both the methanolic and pet ether extract of Cucurbita maxima. In vitro antioxidant activity of the extracts were performed using DPPH radical scavenging, nitric oxide (NO) scavenging, total antioxidant capacity, total phenol content, total flavonoid content, and Cupric Reducing Antioxidant Capacity assays. The most prominent antioxidant activity was observed with the CSM in the DPPH free radical scavenging test with an IC50 value of 1667.23±11.00271 μg/ml as opposed to that of standard ascorbic acid (IC50 value of 15.707± 1.181 μg/ml.) In total antioxidant capacity method, CMP showed the highest activity (427.81±11.4 mg ascorbic acid/g). The total phenolic and flavonoids content were determined by Folin-Ciocalteu Reagent and aluminium chloride colorimetric method, respectively. The highest total phenols and total flavonoids content were found in CMM and LP with the value of 79.06±16.06 mg gallic acid/g & 119.0±1.41 mg quercetin/g, respectively. In nitric oxide (NO) scavenging the most prominent antioxidant activity was observed in CMM with an IC50 value of 8.119± 0.0036 μg/ml. The Cupric reducing capacity of the extracts was strong and dose dependent manner and CSM showed lowest reducing capacity. The cytotoxicity was determined by Brine shrimp lethality test and among these extracts most potent cytotoxicity was shown by CMM with LC50 value 16.98 µg/ml. The obtained results indicate that the investigated plants could be potential sources of natural antioxidants and can be used for various types of diseases.

Keywords: antioxidant, cytotoxicity, methanol, petroleum ether

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Authors: M. N. Khajavi, S. Nasiri, E. Farokhi, M. R. Bavir

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Alcohol fuels are renewable, have low pollution and have high octane number; therefore, they are important as fuel in internal combustion engines. Percentage detection of these alcoholic fuels with gasoline is a complicated, time consuming, and expensive process. Nowadays, these processes are done in equipped laboratories, based on international standards. The aim of this research is to determine percentage detection of different fuels based on vibration analysis of engine block signals. By doing, so considerable saving in time and cost can be achieved. Five different fuels consisted of pure gasoline (G) as base fuel and combination of this fuel with different percent of ethanol and methanol are prepared. For example, volumetric combination of pure gasoline with 10 percent ethanol is called E10. By this convention, we made M10 (10% methanol plus 90% pure gasoline), E30 (30% ethanol plus 70% pure gasoline), and M30 (30% Methanol plus 70% pure gasoline) were prepared. To simulate real working condition for this experiment, the vehicle was mounted on a chassis dynamometer and run under 1900 rpm and 30 KW load. To measure the engine block vibration, a three axis accelerometer was mounted between cylinder 2 and 3. After acquisition of vibration signal, eight time feature of these signals were used as inputs to an Adaptive Neuro Fuzzy Inference System (ANFIS). The designed ANFIS was trained for classifying these five different fuels. The results show suitable classification ability of the designed ANFIS network with 96.3 percent of correct classification.

Keywords: internal combustion engine, vibration signal, fuel composition, classification, ANFIS

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Authors: Alaa M. M. Badr Eldin, Marwa I. Ezzat, Mohammed S. Sedeek, Manal S. Afifi, Omar M. Sabry

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Cytotoxic activity of the total methanol extract against breast cancer cell line MCF-7 was amazing IC50 at 54 ug/ml. 130 polyphenolic compounds were tentatively identified in pomegranate peel (Punica granatum L.) methanol extract using HPLC-MS/MS technique. The antiestrogenic activity of the polyphenolic constituents found in pomegranate extract was confirmed experimentally in-vitro and by the in-silico molecular docking using gallagic acid, ellagic acid, and Punicalagin as these are considered model compounds confirmed in pomegranate peel extract. The methanolic extract was found to suppress ER, TGF-β, and NF-kB in-vitro gene expression strongly, and that was verified by qPCR and Western Blot gel electrophoresis techniques.

Keywords: HPLC-MS/MS, pomegranate, breast cancer, ovarian cancer, ER, TGF-β, NF-kB

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Authors: S. B. Bhandare, K. S. Laddha

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Podphyllum hexandrum belonging to family berberidaceae has gained attention in phytochemical and pharmacological research as it shows excellent anticancer activity and has been used in treatment of skin diseases, sunburns and radioprotection. Chemically it contains lignans and flavonoids such as kaempferol, quercetin and their glycosides. Objective: To isolate and identify Kaempferol and Quercetin from Podophyllum rhizome. Method: The powdered rhizome of Podophyllum hexandrum was subjected to soxhlet extraction with methanol. This methanolic extract is used to obtain podophyllin. Podohyllin was extracted with ethyl acetate and this extract was then concentrated and subjected to column chromatography to obtain purified kaempferol and quercetin. Result: Isolated kaempferol, quercetin were light yellow and dark yellow in colour respectively. TLC of the isolated compounds was performed using chloroform: methanol (9:1) which showed single band on silica plate at Rf 0.6 and 0.4 for kaempferol and quercetin. UV spectrometric studies showed UV maxima (methanol) at 259, 360 nm and 260, 370 nm which are identical with standard kaempferol and quercetin respectively. Both IR spectra exhibited prominent absorption bands for free phenolic OH at 3277 and 3296.2 cm-1 and for conjugated C=O at 1597 and 1659.7 cm-1 respectively. The mass spectrum of kaempferol and quercetin showed (M+1) peak at m/z 287 and 303.09 respectively. 1H NMR analysis of both isolated compounds exhibited typical four-peak pattern of two doublets at δ 6.86 and δ 8.01 which was assigned to H-3’,5’ and H-2’,6’ respectively. Absence of signals less than δ 6.81 in the 1H NMR spectrum supported the aromatic nature of compound. Kaempferol and Quercetin showed 98.1% and 97% purity by HPLC at UV 370 nm. Conclusion: Easy and simple method for isolation of Kaempferol and Quercetin was developed and their structures were confirmed by UV, IR, NMR and mass studies. Method has shown good reproducibility, yield and purity.

Keywords: flavonoids, kaempferol, podophyllum rhizome, quercetin

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Authors: M. Nafis Alfarizi, Dinda A. Utami, Arif Hidayat

Abstract:

Biodiesel is one solution to overcome the use of petroleum fuels. Many alternative feedstocks that can be used among which canola oil. The purpose of this study was to determine the ability of canola oil and KOH for the trans-esterification reaction in biodiesel production. Canola oil has a very high purity that can be used as an alternative feedstock for biodiesel production and expected it will be produced biodiesel with excellent quality. In this case of study, we used trans-esterification process wherein the triglyceride is reacted with an alcohol with KOH as a catalyst, and it will produce biodiesel and glycerol as byproduct and we choose trans-esterification process because canola oil has a 0,445% FFA content. The variables studied in this research include the comparison of canola oil and methanol, temperature, time, and the percent of catalyst used. In this study the method of analysis we use GCMS and FTIR to know what the characteristic in canola oil. Development of canola oil seems to be the perfect solution to produce high-quality biodiesel. The reaction conditions resulted in 97.87% -w methyl ester (biodiesel) product by using a 0.5% wt KOH catalyst with canola and methanol ratio 1:8 at 60°C.

Keywords: biodiesel, canola oil, KOH, trans-esterification

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Authors: Yongzheng Li, Hongfang Ma, Qiwen Sun, Haitao Zhang, Weiyong Ying

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Radial profiles of particle velocities were investigated in a 6.1 m tall methanol-to-olefins cold model experimental device using a TSI laser Doppler velocimeter. The measurement of axial levels was conducted in the full developed region. The effect of axial level on flow development was not obvious under the same operating condition. Superficial gas velocity and solid circulating rate had significant influence on particle velocity in the center region of the riser. Besides, comparisons between upward, downward and average particle velocity were conducted. The average particle velocity was close to upward velocity and higher than downward velocity in radial locations except the wall region of riser.

Keywords: circulating fluidized bed, laser doppler velocimeter, particle velocity, radial profile

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Authors: Sunny Arora, Meghal A. Desai

Abstract:

An impetus towards green consumerism and implementation of sustainable techniques, consumption of natural products and utilization of environment friendly techniques have gained accelerated acceptance. Butein, a natural colorant, has many medicinal properties apart from its use in dyeing industries. Extraction of butein from the flowers of flame of forest was carried out using ultrasonication bath. Solid loading (2-6 g), extraction time (30-50 min), volume of solvent (30-50 mL) and types of solvent (methanol, ethanol and water) have been studied to maximize the yield of butein using the Taguchi method. The highest yield of butein 4.67% (w/w) was obtained using 4 g of plant material, 40 min of extraction time and 30 mL volume of methanol as a solvent. The present method provided a greater reduction in extraction time compared to the conventional method of extraction. Hence, the outcome of the present investigation could further be utilized to develop the method at a higher scale.

Keywords: butein, flowers of Flame of the Forest, Taguchi method, ultrasonic bath

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Authors: Djemai Zoughlache Soumia, Yahia Mouloud, Lekbir Adel, Meslem Meriem, Maouchi Madiha, Bahi Ahlem, Benbia Souhila

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Natural extracts is known for their contents of biologically active molecules. In this context, we attempted to evaluate the antioxidant activity of the methanolic extract prepared from the bark of the roots of Zizyphus lotus. The quantitative analysis based on the dosage, phenolic compounds, flavonoids and tannins provided following values: 0.39 ± 0.007 ug EAG/mg of extract for phenolic compounds, 0.05 ± 0.02ug EQ/mg extract for flavonoids and 0.0025 ± 7.071 E-4 ECT ug/mg extract for tannins. The study of the antioxidant activity by the DPPH test in vitro showed a powerful antiradical power with an IC50 = 8,8 ug/ml. For the DPPH test in vivo we used two rats lots, one lot with a dose of 200 mg/kg of the methanol extract and a control lot. We found a significant difference in antiradical activity with p < 0.05.

Keywords: Zizyphus lotus, antioxidant activity, DPPH, phenolic compounds, flavonoids, tannins

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Authors: Chow Jeng Hei, Pavel Tkalich, Low Kai Sheng Bryan

Abstract:

Due to the growing demand for sustainability in the maritime industry, there has been a significant increase in focus on alternative fuels such as biofuels, liquefied natural gas (LNG), hydrogen, methanol and ammonia to reduce the carbon footprint of vessels. Alternative fuels offer efficient transportability and significantly reduce carbon dioxide emissions, a critical factor in combating global warming. In an era where the world is determined to tackle climate change, the utilization of methanol is projected to witness a consistent rise in demand, even during downturns in the oil and gas industry. Since 2022, there has been an increase in methanol loading and discharging operations for industrial use in Singapore. These operations were conducted across various storage tank terminals at Jurong Island of varying capacities, which are also used to store alternative fuels for bunkering requirements. The key objective of this research is to support the green shipping industries in the transformation to new fuels such as methanol and ammonia, especially in evolving the capability to inform risk assessment and management of spills. In the unlikely event of accidental spills, a highly reliable forecasting system must be in place to provide mitigation measures and ahead planning. The outcomes of this research would lead to an enhanced metocean prediction capability and, together with advanced sensing, will continuously build up a robust digital twin of the bunkering operating environment. Outputs from the developments will contribute to management strategies for alternative marine fuel spills, including best practices, safety challenges and crisis management. The outputs can also benefit key port operators and the various bunkering, petrochemicals, shipping, protection and indemnity, and emergency response sectors. The forecasted datasets provide a forecast of the expected atmosphere and hydrodynamic conditions prior to bunkering exercises, enabling a better understanding of the metocean conditions ahead and allowing for more refined spill incident management planning

Keywords: clean fuels, hydrodynamics, coastal engineering, impact assessments

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Authors: Sunil Kumar

Abstract:

Background: The present study was performed to investigate the antidiabetic effect of the constituents isolated from Sarca asoca by enzyme inhibitory activity. Methods: The dried leaves of Sarca asoca were defatted with petroleum ether and further the same amount plant materials were extracted with methanol. The dried methanol extract was subjected to fractionation and chromatographic separation, which led to the isolation of kaemferol, β-sitosterol and quercetin stigmasterol. Their structures were elucidated on the basis of spectroscopic studies as well as by comparison with the data available in the literature. The compounds were evaluated for in vitro enzyme inhibition effect. Results: The isolated compounds kaemferol, β-sitosterol and stigmasterol showed 45.32, 40.5 and 41.23% α-amylase inhibition respectively and 43.45, 39.29 and 32.43% α-glucosidase inhibition respectively at the conc. of 50 µg/kg. Conclusion: The compounds isolated from Sarca asoca showed in vitro and in vivo antidiabetic activity. So, Euphorbia hirta is a beneficial plant for management of diabetic disorders.

Keywords: diabetes, quercetin, sitosterol, stigmasterol

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Authors: Dalvir Kataria, Khushminder Kaur Chahal, Amit Kumar

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The carrot seed essential oil was obtained by hydrodistillation. Hexane, dichloromethane, and methanol solvents were used for extraction of carrot seed by Soxhlet extraction methods. The major and minor compounds identified in carrot seed essential oil were carotol (52.73), daucol (5.10), daucene (5.68), (E)-β-farnesene (5.40), β-cubebene (3.19), longifolenaldehyde (3.23), β-elimene (3.23), (E)-caryophyllene (1.22), β-bisabolene (2.95) etc. The chemical composition of hexane, dichloromethane, and methanol extracts was different. Carotol was the common compound present. Major compounds isolated were from the carrot seed essential oil by column chromatography. Chemical transformations of carotol (2) with mercuric acetate/sodium borohydride, dry hydrochloric acid gas, acetonitrile/sulfuric acid, selenium dioxide/t-butyl hydrogen peroxide, N-bromosuccinimide, hydrogen iodide, and phenol were carried out. The derivatives of carotol were designed to explore the significance of some structural modifications in relation to antioxidant activities. The structures of major compounds and derivatives were confirmed on the basis of FT-IR, 1HNMR and 13CNMR spectroscopy. Antioxidant activity of carrot seed essential oil, various extracts and isolated compounds were tested by in vitro models involving 2, 2-diphenyl-1-picrylhydrazyl (DPPH•), hydroxyl (OH•), nitric oxide (NO•), superoxide radical scavenging methods and ferric reducing antioxidant power assay (FRAP). Chemical transformations of major isolated compound carotol were carried out, and antioxidant activity of all compounds was undertaken. The major sesquiterpenoidcarotol isolated from carrot seed essential oil showed the highest antioxidant activity in all the methods. The methanol extract showed higher antioxidant potential as compared to carrot seed essential oil, hexane, and dichloromethane extracts.

Keywords: antioxidant, carotol, carrot, DPPH

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Authors: S.Kauroo, J. Govinden Soulange, D. Marie

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Psiadia species from the Asteraceae are traditionally used in the folk medicine of Mauritius to treat cutaneous and bronchial infections. The present study aimed at validating the phytomedicinal properties of the selected species from the Asteraceae family, namely Psiadia arguta, Psiadia viscosa, Psiadia lithospermifolia, and Distephanus populifolius. Dried hexane, ethyl acetate, and methanol leaf extracts were studied for their antioxidant properties using the DPPH (1, 1-diphenyl-2-picryl-hydrazyl), FRAP (Ferric Reducing Ability of Plasma), and Deoxyribose assays. Antibacterial activity against human pathogenic bacteria namely Escherichia coli (ATCC 27853), Staphylococcus aureus (ATCC 29213), Enterococcus faecalis (ATCC 29212), Klebsiella pneumonia (ATCC27853), Pseudomonas aeruginosa (ATCC 27853), and Bacillus cereus (ATCC 11778) was measured using the broth microdilution assay. Qualitative phytochemical screening using standard methods revealed the presence of coumarins, tannins, leucoanthocyanins, and steroids in all the tested extracts. The measured phenolics level of the selected plant extracts varied from 24.0 to 231.6 mg GAE/g with the maximum level in methanol extracts in all four species. The highest flavonoids and proanthocyanidins content was noted in Psiadia arguta methanolic extracts with 65.7±1.8 mg QE/g and 5.1±0.0 mg CAT/g dry weight (DW) extract, respectively. The maximum free radical scavenging activity was measured in Psiadia arguta methanol and ethyl acetate extracts with IC50 11.3±0.2 and 11.6± 0.2 µg/mL, respectively and followed by Distephanus populifolius methanol extracts with an IC50 of 11.3± 0.8 µg/mL. The maximum ferric reducing antioxidant potential was noted in Psiadia lithospermifolia methanol extracts with a FRAP value of 18.8 ± 0.4 µmol Fe2+/L/g DW. The antioxidant capacity based on DPPH and Deoxyribose values were negatively related to total phenolics, flavonoid and proanthocyanidins content while the ferric reducing antioxidant potential were strongly correlated to total phenolics, flavonoid and proanthocyanidins content. All four species exhibited antimicrobial activity against the tested bacteria (both Gram-negative and Gram-positive). Interestingly, the hexane and ethyl acetate extracts of Psiadia viscosa and Psiadia lithospermifolia were more active than the control antibiotic Chloramphenicol. The Minimum inhibitory concentration (MIC) values for hexane and ethyl acetate extracts of Psiadia viscosa and Psiadia lithospermifolia against the tested bacteria ranged from (62.5 to 500 µg/ml). These findings validate the use of these tested Asteraceae in the traditional medicine of Mauritius and also highlight their pharmaceutical potential as prospective phytomedicines.

Keywords: antibacterial, antioxidant, DPPH, flavonoids, FRAP, Psiadia spp

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Authors: Palash Soni, Vivek Kumar Gaba, Shubhankar Bhowmick, Bidyut Mazumdar

Abstract:

Refrigeration technology is a fast developing field at the present era since it has very wide application in both domestic and industrial areas. It started from the usage of simple ice coolers to store food stuffs to the present sophisticated cold storages along with other air conditioning system. A variety of techniques are used to bring down the temperature below the ambient. Adsorption refrigeration technology is a novel, advanced and promising technique developed in the past few decades. It gained attention due to its attractive property of exploiting unlimited natural sources like solar energy, geothermal energy or even waste heat recovery from plants or from the exhaust of locomotives to fulfill its energy need. This will reduce the exploitation of non-renewable resources and hence reduce pollution too. This work is aimed to develop a model for a solar adsorption refrigeration system and to simulate the same for different operating conditions. In this system, the mechanical compressor is replaced by a thermal compressor. The thermal compressor uses renewable energy such as solar energy and geothermal energy which makes it useful for those areas where electricity is not available. Refrigerants normally in use like chlorofluorocarbon/perfluorocarbon have harmful effects like ozone depletion and greenhouse warming. It is another advantage of adsorption systems that it can replace these refrigerants with less harmful natural refrigerants like water, methanol, ammonia, etc. Thus the double benefit of reduction in energy consumption and pollution can be achieved. A thermodynamic model was developed for the proposed adsorber, and a universal MATLAB code was used to simulate the model. Simulations were carried out for a different operating condition for the silicagel-methanol working pair. Various graphs are plotted between regeneration temperature, adsorption capacities, the coefficient of performance, desorption rate, specific cooling power, adsorption/desorption times and mass. The results proved that adsorption system could be installed successfully for refrigeration purpose as it has saving in terms of power and reduction in carbon emission even though the efficiency is comparatively less as compared to conventional systems. The model was tested for its compliance in a cold storage refrigeration with a cooling load of 12 TR.

Keywords: adsorption, refrigeration, renewable energy, silicagel-methanol

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Authors: Angalabiri-Owei E. Bekekeme, Brambaifa Nelson

Abstract:

In view of the peculiar environment of the Niger Delta, access to modern health care is limited, hence the inhabitants especially those in the swampy areas resorts to sourcing for alternatives cure for their ailments using plants commonly found in this area without scientific evaluation. Rhizophora racemosa, G. F. Meyer (Rhizophoraceae) is the most abundant mangrove plant in the Niger Delta Area of Nigeria. The plant has been observed to be used for relief of a toothache and dysmenorrhoea among some Ijaw communities in the region. This work has revealed the likely potential of the plant in drug discovery and development. The crude methanol extract at doses of 300 mg/kg and 600 mg/kg (intraperitoneal) were tested for analgesic effect using fresh egg albumin induced inflammatory pain and Randall–Sellito method to assess the pain threshold. The anti-inflammatory effect was also evaluated with the extract at doses of 300 mg/kg and 600 mg/kg (intraperitoneal) using acute inflammatory model; fresh egg albumin induced paw oedema and assessed using Plethysmometer in rats. The methanol extracts 300 mg/kg and 600 mg/kg exhibited a significant (P < 0.001) and dose-dependent analgesic activity compared with the negative control and a standard drug diclofenac using ANOVA with Least Significant Difference post hoc test as evidenced by increased pain threshold. Also, the extract significantly (P < 0.001) reduced the rat paw oedema induced by the sub plantar injection of fresh egg albumin when compared with the negative control and a standard diclofenac using above statistical methods. This study revealed that the plant possesses analgesic and anti-inflammatory activities hence provide scientific bases for use as medicine.

Keywords: analgesic, anti-inflammatory, plethysmometer, Rhizophora racemosa

Procedia PDF Downloads 318