scholarly journals Microwave Assisted Alkaline Pretreatment of Algae Waste in the Production of Cellulosic Bioethanol

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5891
Author(s):  
Rocío Maceiras ◽  
Víctor Alfonsín ◽  
Luis Seguí ◽  
Juan F. González
Keyword(s):  
Microwave Power ◽  
Reducing Sugars ◽  
Irradiation Time ◽  
Alkaline Pretreatment ◽  
Liquid Ratio ◽  
Fermentation Efficiency ◽  
Microwave Assisted ◽  
Microwave Effect ◽  
Solid Liquid ◽  
Bioethanol Yield

Biomass pretreatment has an important role in the production of cellulosic bioethanol. In this study, the effectiveness of microwave assisted alkaline pretreatment of algae waste was analysed. After pretreatment, the product was hydrolysed using sulphuric acid. The effects of microwave power, irradiating time, solid–liquid ratio and NaOH concentration were examined. Under the best conditions, the fermentable sugars were converted to cellulosic bioethanol using Saccharomyces Cerevisiae with a bioethanol yield of 1.93 ± 0.01 g/g and a fermentation efficiency of 40.4%. The reducing sugars concentration was 30% higher than that obtained from conventional hydrolysis without pretreatment. The obtained results suggest that microwave assisted alkaline pretreatment is effective in improving the production of cellulosic bioethanol of algae waste compared to that without microwave effect. Considering energy consumption, low microwave power and short microwave irradiation time are favourable for this pretreatment.

Response Surface Method to Optimize Pretreatment of Rice Husk by Microwave-Assisted NaOH Solution

2012 ◽  
Vol 550-553 ◽  
pp. 1486-1490 ◽  
Author(s):  
Dan Ni Han ◽  
Ding Xie ◽  
Yan Gao ◽  
Qiong Zhang ◽  
Jing Zhu
Keyword(s):  
Response Surface ◽  
Response Surface Method ◽  
Rice Husk ◽  
Microwave Power ◽  
Irradiation Time ◽  
Liquid Ratio ◽  
Microwave Assisted ◽  
Surface Method ◽  
Naoh Solution

The effect of microwave-assisted NaOH solution to pretreat rice husk was studied with RSM (Response Surface Method). When NaOH concentration; microwave power; irradiation time and solid-to-liquid ratio, are 1.5%; 650 w; 16 min and 1:12 respectively, the rice husk which are treated under such conditions can be hydrolyzed by the enzyme to get 56.24% sugars.

scholarly journals Is the Household Microwave Recommended to Obtain Antioxidant-Rich Extracts from Lycium barbarum Leaves?

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 656
Author(s):  
Luna Pollini ◽  
Federica Ianni ◽  
Giuseppa Verducci ◽  
Francesca Blasi ◽  
Lina Cossignani
Keyword(s):  
Antioxidant Activity ◽  
Microwave Power ◽  
Phenolic Content ◽  
Irradiation Time ◽  
Total Phenolic ◽  
Liquid Ratio ◽  
Leaf Extracts ◽  
Lycium Barbarum ◽  
Plant Materials ◽  
Solid Liquid

Nowadays, much interest is devoted to the extraction of plant materials, considering also their waste and by-products, to obtain antioxidant-rich products. The effect of household microwave-assisted extraction (MAE) on the phenolic content and antioxidant activity of Lycium barbarum leaf extracts was investigated. An experimental design approach was adopted considering solid/liquid ratio (1, 3, and 5 g of leaves in 150 mL water), irradiation time (1, 3, and 5 min), and microwave power (300, 400, and 500 W) as independent variables. These three factors and their interactions were studied to evaluate the effect of MAE conditions on the responses of total phenolic content, antioxidant activity, and chlorogenic acid content. The results showed that the analytical parameters were positively influenced by the solid/liquid ratio and time. On the contrary, microwave power was inversely correlated with the investigated responses. This research revealed that microwave extraction conditions should be carefully monitored to obtain bioactive-rich aqueous extracts with high antioxidant activity. A comparison with household traditional methods showed an unexpected lower phenolic content and antioxidant activity for MAE extract in respect to the decoction and infusion. In fact, it was found that L. barbarum leaf infusion had the best functional properties, regarding the investigated characteristics. The outcome of this study has implications for raising awareness that household preparation conditions strongly affect the health properties of herbal extracts.

scholarly journals Extraction of Phytosterol Concentration in Different Legume Pods by Using Microwave-Assisted Hydrodistillation

2019 ◽  
Vol 19 (3) ◽  
pp. 796
Author(s):  
Noormazlinah Noormazlinah ◽  
Norlaili Hashim ◽  
Abdurahman Hamid Nour ◽  
Mimi Sakinah Abdul Munaim ◽  
Maria Pilar Almajano ◽  
...  
Keyword(s):  
Bioactive Compounds ◽  
Microwave Power ◽  
Ethanol Concentration ◽  
Irradiation Time ◽  
Optimal Conditions ◽  
Solvent Concentration ◽  
Visible Spectroscopy ◽  
Optimum System ◽  
Microwave Assisted ◽  
Extraction Parameters

The traditional ways in the extraction of bioactive compounds using conventional methods are disadvantageous from both economic and environmental perspectives. In this, the potential of microwave-assisted hydrodistillation conditions for extraction of phytosterol from legume pods was investigated. Salkowski test performed on the legume pod has shown the reddish brown in all sample which confirmed the presence of phytosterol qualitatively. Liebermann-Burchard procedure and ultraviolet-visible spectroscopy (UV-Vis) apparatus were used to study the concentration of phytosterol at different extraction parameters which are temperature (25–80 °C), solvent concentration (50–100% v/v), irradiation time (1–10 min) and microwave power (400–800 W). The optimal conditions for highest yield of extract (0.219 mg/L) were obtained at a microwave power of 600 W, the irradiation time of 6 min, and ethanol concentration of 75% v/v. Results obtained in this study have shown the capability of microwave-assisted hydrodistillation in the extraction of phytosterol from legume pod. Further works are nevertheless required to provide a deeper understanding of the mechanisms involved to facilitate the development of an optimum system applicable to the industry.

Meso-mechanics simulation analysis of microwave-assisted mineral liberation

2015 ◽  
Author(s):  
Qin Like ◽  
Dai Jun ◽  
Yuan Liqun
Keyword(s):  
Energy Consumption ◽  
Microwave Irradiation ◽  
Power Density ◽  
Microwave Power ◽  
Mineral Content ◽  
Crystal Size ◽  
Irradiation Time ◽  
Mineral Crystal ◽  
Microwave Assisted ◽  
Time And Energy

Microwave-assisted crushing and grinding can improve efficiency and reduce energy consumption. This paper takes rock grains with galena and calcite as the research object to establish a two-dimensional computational model through the finite difference software FLAC2D. It analyzes the process and law of mineral boundary failure under microwave irradiation, and assesses the effects of four factors, namely, microwave irradiation time, power density, mineral crystal size, and mineral content, on mineral boundary failure. Results indicate an optimal microwave irradiation period for the rapid failure of mineral boundary. Moreover, irradiation time and energy consumption can be reduced by increasing the microwave power density. However, irradiation time and energy consumption are basically unchanged when the microwave power density is above a certain threshold. Mineral content slightly affects the microwave irradiation time, whereas mineral crystal size significantly affects the microwave irradiation time. In addition, a larger-sized mineral crystal requires less irradiation time and energy consumption to reach the same failure rate. However, irradiation time and energy consumption slightly change when the crystal size is larger than a certain value.

Enhanced production of reducing sugars from paragrass using microwave-assisted alkaline pretreatment

2020 ◽  
Author(s):  
Sasikarn Nuchdang ◽  
Vipa Thongtus ◽  
Maneerat Khemkhao ◽  
Suchata Kirdponpattara ◽  
Elvin J. Moore ◽  
...  
Keyword(s):  
Reducing Sugars ◽  
Alkaline Pretreatment ◽  
Microwave Assisted ◽  
Enhanced Production

scholarly journals Screening of Microwave-Assisted-Batch Extraction Parameters for Recovering Total Phenolic and Flavonoid Contents from Chromolaena odorata Leaves through Two-Level Factorial Design

2019 ◽  
Vol 19 (2) ◽  
pp. 511 ◽  
Author(s):  
Oluwaseun Ruth Alara ◽  
Abdurahman Hamid Nour ◽  
Siti Kholijah Binti Abdul Mudalip
Keyword(s):  
Factorial Design ◽  
Microwave Power ◽  
Ethanol Concentration ◽  
Irradiation Time ◽  
Power Level ◽  
Feed Ratio ◽  
Total Phenolic ◽  
Chromolaena Odorata ◽  
Microwave Assisted ◽  
Microwave Power Level

Microwave-assisted extraction (MAE) of phenolic compounds from Chromolaena odorata leaves was investigated using one-factor-at-a-time (OFAT) and two-level factorial design. The MAE parameters studied were irradiation time (A: 1–5 min); microwave power level (B: 400-800 W); extraction temperature (C: 60–80 °C); solvent/feed ratio (D: 8:1–14:1 mL/g); and ethanol concentration (E: 20–60% v/v). The optima yields of TPC and TFC were 56.13 mg GAE/g d.w. and 44.78 mg QE/g d.w., respectively were achieved from MAE of C. odorata leaf at irradiation time of 2 min, microwave power of 600 W, temperature of 60 °C, solvent:feed ratio of 10:1 mL/g, and ethanol concentration of 40% v/v through one-factor-at-time (OFAT) experimental trials. The results obtained from a two-level factorial design experiments reflected that only ethanol concentration (20–60% v/v), irradiation time (1–5 min) and microwave power level (400–800 W) had significant effects on the yields of total phenolic content (TPC) and total flavonoid content (TFC) from C. odorata leaves (p < 0.05). However, temperature and solvent/feed ratio was not significant. In addition, the interactions AB (irradiation time and microwave power) and AE (irradiation time and ethanol concentration) contributed greatly to the recovery yields.

scholarly journals Ekstraksi Polifenol Total dari Herba Suruhan (Peperomia pellucida [L.] KUNTH) Menggunakan Metode Citric Acid-Glucose Based Microwave Assisted Extraction

2019 ◽  
Vol 10 ◽  
pp. 76-80
Author(s):  
Duwi Meiliyani ◽  
Sabaniah ◽  
Islamudin Ahmad
Keyword(s):  
Citric Acid ◽  
Extraction Method ◽  
Microwave Assisted Extraction ◽  
Green Solvent ◽  
Liquid Ratio ◽  
Extraction Condition ◽  
Total Polyphenols ◽  
Microwave Assisted ◽  
Assisted Extraction ◽  
Solid Liquid

This study aims to determine the effect of citric acid-glucose based microwave assited extraction (MAE) method on total polyphenols content from (Peperomia pellucida [L.] Kunth) herbs. Dried samples were extracted using green solvent glucose citric acid with a ratio of 1: 1 g/g, 3: 1 g/g, and 5: 1 g/g, respectively, 30% microwave power for 5 minutes, and 1:5 g /mL solid-liquid ratio. Then the obtained extract solution was performed determination total polyphenols content using Folin-Ciocalteu reagent, and the absorbance was measured using a UV-Vis spectrophotometer at 791 nm. Based on the results, obtained total polyphenols content according to the extraction condition namely 214.405 mg GAE/g sample (3: 1 g /g solvent), 84.833 mg GAE /g sample (1: 1 g /g solvent) and 53,9451 mg GAE/g sample (5: 1 g /g solvent), respectively. This study is a preliminary data about the use of citric acid-glucose based microwave assisted extraction method on total polyphenols content from this plant quickly, easily and efficiently.

Study on Water Extraction Technology of Litsea cubeba Essential Oil from the Seed of Litsea cubeba (Lour.) Pers. Assisted by Microwave and Ultrasonic

2010 ◽  
Vol 156-157 ◽  
pp. 1113-1116
Author(s):  
Guo En Yang ◽  
Xiang Zhou Li ◽  
Min Zhang ◽  
Ying He Li
Keyword(s):  
Essential Oil ◽  
Microwave Power ◽  
Extraction Process ◽  
Water Extraction ◽  
Average Yield ◽  
Liquid Ratio ◽  
Extraction Technology ◽  
Litsea Cubeba ◽  
Optimal Technology ◽  
Solid Liquid

Evaluated with the yield of litsea cubeba essential oil, water extraction technology of essential oil from the seed of Litsea Cubeba (Lour.) Pers. assisted by microwave and ultrasonic is studied for the first time in this paper. The optimal water extraction technology of litsea cubeba essential oil assisted by pure microwave is as follows: extracting time 40 minutes, microwave power 650 W, solid-liquid ratio 1:4 (g/mL). Average yield of litsea cubeba essential oil is up to 10.287% (g/g) under the above optimal technology. The optimal water extraction technology of litsea cubeba essential oil assisted by microwave together with ultrasonic is as follows: extracting time 8 minutes, microwave power 600 W, solid-liquid ratio 1:7 (g/mL), extracting temperature 85 . Average yield of litsea cubeba essential oil is up to 14.188% under the above optimal technology. Microwave and ultrasonic can effectively enhance the extraction process of litsea cubeba essential oil.

scholarly journals Phase Transformation of VO2Nanoparticles Assisted by Microwave Heating

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Phatcharee Phoempoon ◽  
Lek. Sikong
Keyword(s):  
Microwave Power ◽  
Irradiation Time ◽  
Power Level ◽  
Thermal Analyses ◽  
Morphological Properties ◽  
Microwave Assisted Synthesis ◽  
Tem Analysis ◽  
Microwave Assisted ◽  
Thermochromic Properties ◽  
Microwave Power Level

The microwave assisted synthesis nowadays attracts a great deal of attention. Monoclinic phase VO2(M) was prepared from NH4VO3andH2C2O4·2H2Oby a rapid microwave assisted technique. The synthesis parameters, microwave irradiation time, microwave power, and calcinations temperature were systematically varied and their influences on the structure and morphology were evaluated. The microwave power level has been carried out in range 180–600 W. TEM analysis demonstrated nanosized samples. The structural and morphological properties were measured using XRD, TEM, and thermal analyses. The variations of vanadium phase led to thermochromic properties.

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