scholarly journals CO2 Carbonation of Olivine-Admixed Marine Clay: Suitability for Bottom Liner Application

2021 ◽  
Vol 11 (7) ◽  
pp. 3164
Author(s):  
Endene Emmanuel ◽  
Vivi Anggraini ◽  
Agusril Syamsir ◽  
Afshin Asadi

This paper focuses on employing an optimization approach in evaluating the hydraulic conductivity (HC) of CO2-carbonated olivine-admixed marine clay for possible utilization as a hydraulic barrier in engineered landfills to minimize leachate migration. The attainable region technique was used to optimize the olivine particle size during the grinding process before treating the soil, while the response surface methodology was used in designing the experiments, evaluating the results, and optimizing the variables responsible for reducing the HC of the CO2-carbonated olivine-treated clay. The effects of the control factors (olivine content, carbonation time, and carbonation pressure) on the response (HC) were studied by variance analysis. The factors and the response were related by a developed regression model. Predicted values from the model were in concurrence with their experimental counterparts. The results show that the HC of the CO2-carbonated olivine-treated clay samples met the Malaysian regulatory specification of ≤10−8 m/s for liner utilization. The optimum conditions were 24.7% olivine content, 20.1 h carbonation time, and 161 kPa carbonation pressure, which decreased the HC by approximately 98%. CO2-carbonation and olivine blend proved to be a sustainable technique to reduce the clay’s HC for possible application as a liner material in engineered landfills.

2020 ◽  
Vol 16 (1) ◽  
pp. 30-33
Author(s):  
Wong Lee Peng ◽  
Siti Hamidah Mohd Setapar ◽  
Hasmida Mohd Nasir

Hibiscus sabdariffa, commonly known as Roselle, is a native plant in Malaysia that is rich with bioactive compounds. In the present study, supercritical carbon dioxide (SC-CO2) extraction of Roselle was investigated. The optimum particle size (212µm, 300µm, 425µm, 600µm, and 710µm) to obtain highest yield was pre-determined. The effects of two operating parameters, pressure (20MPa, 25MPa, and 30MPa) and temperature (40 ºC, 60 ºC, and 80 ºC) on extraction yield were studied using response surface methodology (RSM). From the experimental data, the optimum conditions were achieved using particle size 300µm, pressure 27.5MPa, and temperature 50.8 ºC. Using the optimized parameters, the highest extraction yield was predicted to be 163.26 mg-extract/g-dried sample. The validation experimental results were consistent with the predicted values. 


2020 ◽  
Vol 83 (1) ◽  
pp. 85-92
Author(s):  
Mohd Azahar Mohd Ariff ◽  
Muhammad Syafiq Abd Jalil ◽  
Noor ‘Aina Abdul Razak ◽  
Jefri Jaapar

Caesalpinia sappan linn. (CSL) is a plant which is also known as Sepang tree contains various medicinal values such as to treat diarrhea, skin rashes, syphilis, jaundice, drinking water for blood purifying, diabetes, and to improve skin complexion. The aim of this study is to obtain the most optimum condition in terms of the ratio of sample to solvent, particle size, and extraction time to get the highest amount of concentration of the CSL extract. In this study, the ranges of each parameters used were: ratio sample to solvent: 1.0:20, 1.5:20, 2.0:20, 2.5:20, 3.0:20, particle size: 1 mm, 500 um, 250 um, 125 um, 63 um, and extraction time: 1 hr, 2 hr, 3 hr, 4 hr, 5 hr. The concentration was analyzed using a UV-vis spectrophotometer. The optimum conditions were obtained by response surface methodology. From the design, 20 samples were run throughout this experiment. The optimized value from the RSM were 2.0:20 for ratio sample to solvent, 125 µm of particle size and 2.48 hours with the concentration of 37.1184 ppm. The accuracy of the predictive model was validated with 2 repeated runs and the mean percentage error was less than 3%. This confirmed the model’s capability for optimizing the conditions for the reflux extraction of CSL’s wood.


2019 ◽  
Vol 20 (1) ◽  
pp. 39-48 ◽  
Author(s):  
Rasha H. Salman

This study depicts the removal of Manganese ions (Mn2+) from simulated wastewater by combined electrocoagulation/ electroflotation technologies. The effects of initial Mn concentration, current density (C.D.), electrolysis time, and different mesh numbers of stainless steel screen electrodes were investigated in a batch cell by adopting Taguchi experimental design to explore the optimum conditions for maximum removal efficiency of Mn. The results of multiple regression and signal to noise ratio (S/N) showed that the optimum conditions were Mn initial concentration of 100 ppm, C.D. of 4 mA/cm2, time of 120 min, and mesh no. of 30 (wire/inch). Also, the relative significance of each factor was attained by the analysis of variance (ANOVA) which indicates that the percentage of contribution followed the order: time (47.42%), C.D. (37.13%), Mesh number (5.73%), and Mn initial Conc. (0.05%). The electrolysis time and C.D. were the most effective operating parameters and mesh no. had a fair influence on Mn removal efficiency, while the initial conc. of Mn. had no significant effect in the studied ranges of control factors. Regression analysis (R2= 90.16%) showed an acceptable agreement between the experimental and the predicted values, and confirmation test results revealed that the removal efficiency of Mn at optimum conditions was higher than 99%.


2014 ◽  
Vol 67 (1) ◽  
Author(s):  
Liza Md Salleh ◽  
Hartati Hartati ◽  
Mohd. Azizi Che Yunus ◽  
Azila Abd. Aziz

Three operating parameters were pressure, temperature and particle size of supercritical carbon dioxide extraction of oil from Swietenia mahagoni have been optimized by response surface methodology to obtain high yield of oil. Results showed that data were adequately fitted into the second-order polynomial model. The linear and quadratic terms of independent variables of temperature, pressure and particle size have significant effects on the oil yield. Optimum conditions for oil yield within the experimental range of the studied variables were 29.99 MPa, 55.29oC and 0.75 mm, and the oil yield was predicted to be 20.76%.


Author(s):  
GANESH N. SHARMA ◽  
C. H. PRAVEEN KUMAR ◽  
BIRENDRA SHRIVASTAVA ◽  
B. KUMAR

Objective: The present research was designed to produce methylprednisolone containing chitosan-based nanoparticles using Box-Behnken Design (BBD) and Response Surface Methodology (RSM) for optimization. Methods: Nanostructures were prepared using the ionic gelation method with screened process parameters. According to the design, methylprednisolone chitosan-based nanoparticles (MCSNPs) were optimized using factors like methylprednisolone concentration, stirring speed and temperature whereas particle size, zeta potential and % encapsulation efficiency as responses. From the observed values of responses with confirmation location and desirability, the predicted values were very close to the observed values. Results: Observed values for the optimized formulation have a particle size of 243±2.33 nm with an encapsulation efficiency of 79.3±7.2%. Morphology of the particles using scanning electron microscopy reveals nearly spherical shaped particles. Methylprednisolone was released in vitro in a sustained manner for about 24 h in simulated colonic fluid pH 7, pH 7.8 (Fasted state) and phosphate buffer pH 7.4, when compared to simulated colonic fluid at pH 6 (Fed state). Optimized MCSNPs followed Korsmeyer peppas kinetics with drug release mechanism as anomalous transport. Conclusion: Application of Box-Behnken design and Response Surface Methodology using Design Expert software was successfully used in the optimization of methylprednisolone loaded chitosan-based nanoparticles with high encapsulation efficiency.


Food Research ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 232-245
Author(s):  
Noor Eliza M.R. ◽  
Siti Roha A.M. ◽  
Norrizah A.R. ◽  
Adi M.S.

Supercritical carbon dioxide (Sc-CO2) was applied to extract fat and cholesterol from beef floss (BF). A response surface methodology (RSM) based on central composite design (CCD) was employed to optimize the extraction conditions of temperature (30 - 62°C), pressure (7 - 35 MPa), and extraction time (0 - 40 mins). The optimum conditions were estimated to be at 51.0°C and 32.8 MPa for a duration of 32.7 mins. Under such conditions, the percentage of fat and cholesterol reduction plus lightness of Sc-CO2 treated BF (STBF) were 81.12%, 86.17%, and 57.60, respectively. There were no significant differences (p>0.05) between experimental and predicted values, indicating the adequacy of the well-fitting models. Furthermore, the protein and ash content of STBF increased significantly (p<0.05) as a result of the extraction. This study indicated that RSM-CCD can be potentially employed in maximizing the extraction of fat and cholesterol from BF under mild Sc-CO2 conditions.


Author(s):  
Marios Kazasidis ◽  
Elisa Verna ◽  
Shuo Yin ◽  
Rocco Lupoi

AbstractThis study elucidates the performance of cold-sprayed tungsten carbide-nickel coating against solid particle impingement erosion using alumina (corundum) particles. After the coating fabrication, part of the specimens followed two different annealing heat treatment cycles with peak temperatures of 600 °C and 800 °C. The coatings were examined in terms of microstructure in the as-sprayed (AS) and the two heat-treated conditions (HT1, HT2). Subsequently, the erosion tests were carried out using design of experiments with two control factors and two replicate measurements in each case. The effect of the heat treatment on the mass loss of the coatings was investigated at the three levels (AS, HT1, HT2), as well as the impact angle of the erodents (30°, 60°, 90°). Finally, the response surface methodology (RSM) was applied to analyze and optimize the results, building the mathematical models that relate the significant variables and their interactions to the output response (mass loss) for each coating condition. The obtained results demonstrated that erosion minimization was achieved when the coating was heat treated at 600 °C and the angle was 90°.


Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 32
Author(s):  
Waleed H. Hassoon ◽  
Dariusz Dziki ◽  
Antoni Miś ◽  
Beata Biernacka

The objective of this study was to determine the grinding characteristics of wheat with a low moisture content. Two kinds of wheat—soft spelt wheat and hard Khorasan wheat—were dried at 45 °C to reduce the moisture content from 12% to 5% (wet basis). Air drying at 45 °C and storage in a climatic chamber (45 °C, 10% relative humidity) were the methods used for grain dehydration. The grinding process was carried out using a knife mill. After grinding, the particle size distribution, average particle size and grinding energy indices were determined. In addition, the dough mixing properties of wholemeal flour dough were studied using a farinograph. It was observed that decreasing the moisture content in wheat grains from 12% to 5% made the grinding process more effective. As a result, the average particle size of the ground material was decreased. This effect was found in both soft and hard wheat. Importantly, lowering the grain moisture led to about a twofold decrease in the required grinding energy. Moreover, the flour obtained from the dried grains showed higher water absorption and higher dough stability during mixing. However, the method of grain dehydration had little or no effect on the results of the grinding process or dough properties.


2011 ◽  
Vol 236-238 ◽  
pp. 253-257
Author(s):  
Xian Zhen Zhang ◽  
De Si Sun ◽  
Hai Lin

The strain Jgj-1 was isolated from Gaoan bauxite ore. The relations of desilication of the strain Jgj-1 and the pH of solution, temperature, shaking speed, incubation time, particle size were investigated. The results shows the optimum conditions of bioleaching are as following: at 28°C, initial pH value is 7.2, particle size 0.056mm, 200rpm shaking speed, incubation 5-7 days.


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