Biodiesel was produced through transesterification of refined cotton seed oil with methanol and potassium hydroxide (KOH) as a catalyst using batch mode. The physicochemical properties of cotton seed ...oil and biodiesel as an alternative fuel for diesel engine was characterized through ASTM standards for fuel tests. The functional groups of the biodiesel were investigated using Fourier transform infrared spectroscopy. Influence of key parameters like reaction temperature, reaction time, catalyst concentration and methanol/oil molar ratio were determined using batch mode. These process parameters were optimized using response surface methodology (RSM) and analysis of variance (ANOVA). The significance of the different process parameters and their combined effects on the transesterification efficiency were established through a full factorial central composite design. The results obtained are in good agreement with published data for other vegetable oil biodiesel as well as various international standards for biodiesel fuel. An optimum yield of 96% was achieved with optimal conditions of methanol/oil molar ratio, 6:1; temperature, 55°C; time, 60min; and catalyst concentration, 0.6%. This investigation has shown that cotton seed oil from Nigeria can be used to produce biodiesel.
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•Syngas production from methane and CO2 is maximized using two-stage optimization.•The first-stage maximum syngas yield from Taguchi approach is 2.191 mol (mol CH4)−1.•The ranges of ...three operating parameters are further narrowed in the second-stage optimization.•The maximum syngas yield of 2.304 mol (mol CH4)−1 is achieved in the second stage.•RSM and ANOVA lifts the syngas yield by 5.15% in the second stage.
This study aims to figure out syngas production from methane and CO2 where the catalytic partial oxidation of methane over a rhodium-based catalyst bed in a Swiss-roll reactor is explored. The syngas yield from the best combination of gas hourly space velocity (GHSV), oxygen-to-methane molar ratio (O2/C ratio), and CO2-to- O2 molar ratio (CO2/O2 ratio) is acquired by a two-stage optimization, namely, the Taguchi approach followed by response surface methodology (RSM). In the first stage, the Taguchi approach suggests that the influences of the factors on the syngas yield are ranked by O2/C ratio > CO2/O2 ratio > GHSV, and the maximum syngas yield is 2.191 mol∙(mol-CH4)−1. Thereafter, the ranges of the three operating parameters are narrowed, and RSM and analysis of variance are used in the second stage to obtain a more precise optimization. In this stage, the significance of the regression coefficients indicating that GHSV and the combination of GHSV and O2/C ratio are pronounced. Based on the Box-Behnken experimental design, RSM analysis leads to the maximum syngas yield of 2.304 mol∙(mol CH4)−1, lifting the syngas yield by 5.15% in the second stage. These results reveal that the syngas yield from the two-stage optimization (Taguchi + RSM) is more efficient than from the single-stage.
Microbial electrolysis cells (MECs) are a new bio-electrochemical method for converting organic matter to hydrogen gas (H2). Palm oil mill effluent (POME) is hazardous wastewater that is mostly ...formed during the crude oil extraction process in the palm oil industry. In the present study, POME was used in the MEC system for hydrogen generation as a feasible treatment technology. To enhance biohydrogen generation from POME in the MEC, an empirical model was generated using response surface methodology (RSM). A central composite design (CCD) was utilized to perform twenty experimental runs of MEC given three important variables, namely incubation temperature, initial pH, and influent dilution rate. Experimental results from CCD showed that an average value of 1.16 m3 H2/m3 d for maximum hydrogen production rate (HPR) was produced. A second-order polynomial model was adjusted to the experimental results from CCD. The regression model showed that the quadratic term of all variables tested had a highly significant effect (P < 0.01) on maximum HPR as a defined response. The analysis of the empirical model revealed that the optimal conditions for maximum HPR were incubation temperature, initial pH, and influent dilution rate of 30.23 ∘C, 6.63, and 50.71%, respectively. Generated regression model predicted a maximum HPR of 1.1659 m3 H2/m3 d could be generated under optimum conditions. Confirmation experimentation was conducted in the optimal conditions determined. Experimental results of the validation test showed that a maximum HPR of 1.1747 m3 H2/m3 d was produced.
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•POME used in MEC for H2 as a feasible method and effective treatment technology.•To enhance H2 production from POME, an empirical model was generated using RSM.•Results from CCD showed 1.16 m3 H2/m3 d for maximum HPR was produced.•The confirmation test results showed a maximum HPR of 1.1747 m3 H2/m3 d.
Herein, the dimethyl phthalate (DMP) contamination, as an emerging pollutant, has been cost-effectively removed from landfill leachate through an advanced oxidation process, that is the ...electro-Fenton (EF) process. For this purpose, a quadratic polynomial model was developed via response surface methodology (RSM). Furthermore, the analysis of variance (ANOVA) was performed for evaluating the significance of the proposed assumptions. The actual removal rate of 99.1% was obtained with optimal values of 4 mg L−1 of initial DMP concentration, 50 mM Na2SO4, 600 μL L−1 H2O2, 8-minute electrolytic time, solution pH 3 and 6 mA cm−2 current density for the process variables and was consistent with the expected 99.6% removal rate. Satisfactory correlation coefficients were obtained, and a non-significant value of 0.0618 for model mismatch confirmed that the proposed model is extremely important and can successfully predict the effectiveness of DMP removal. The kinetics of the process and the effect of the presence of some radical scavengers were studied to understand the exact mechanism of DMP degradation. Therefore, it was observed that the reaction of hydroxyl radicals with DMPs followed the first-order kinetics model. Moreover, it was established that the optimal ratio of H2O2/Fe2+ mole was 1.6 and the electricity consumption was 0.157 kWh m−3. The elaborated treatment model used to remove DMP from landfill leachate showed that DMP contamination was effectively removed with a 95.6% removal efficiency in the investigating process.
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•The removal efficiency of 95.6% achieved for the treatment of landfill site leachate•The kinetic of the developed treatment model follows a first-order reaction.•EF-generated hydroxyl radicals were the principal components of the degradation process.
The flow field of cyclone separators was simulated with different vortex finder diameters and inlet dimensions using the Reynolds Stress Model to determine the mechanism of stagnation of axial ...velocity. Two flow patterns of axial velocity in cyclone were observed with changing vortex finder diameter and inlet dimension. As vortex finder diameter and inlet dimension increased, stagnation worsened. If the pressure gradient at the centerline of cyclone separator is positive, stagnation of axial velocity appears in the separation space of cyclone. The variation of the dimensionless critical vortex finder diameter of stagnation with inlet dimension was attributed to the proportion distribution of energy loss in cyclone. Finally, response surface methodology and Muschelknautz method of modeling (MM) were applied and yielded parameters with significant effects on stagnation. The variance analysis confirmed a larger quantitative contribution from inlet dimension on stagnation compared to that of vortex finder diameter, which will be useful for the structural optimization of cyclone.
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•Give the effect of Der and Ka on stagnation in detail for the first time.•Acquire the condition for stagnation just appearing in the separation space.•The mechanism of axial velocity stagnation is revealed.•Provide quantitative contribution from Der and Ka on stagnation by RSM.•Reveal the variation of Dcer with Ka.
This study focuses on the investigation of removal of textile dye (Reactive Yellow) by a combined approach of sorption integrated with biodegradation using low cost adsorbent fly ash immobilized with ...Pseudomonas sp. To ensure immobilization of bacterial species on treated fly ash, fly ash with immobilized bacterial cells was characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and fluorescence microscopy. Comparative batch studies were carried out using Pseudomonas sp, fly ash and immobilized Pseudomonas sp on flyash and were observed that immobilized Pseudomonas sp on flyash acted as better decolourizing agent. The optimized pH, temperature, and immobilized adsorbent dosage for highest percentage of dye removal were observed to be pH 6, 303 K, 1.2 g/L in all the cases. At optimum condition, the highest percentage of dye removal was found to be 88.51%, 92.62% and 98.72% for sorption (flyash), biodegradation (Pseudomonas sp) and integral approach (Pseudomonas sp on flyash) respectively. Optimization of operating parameters of textile dye decolourization was done by response surface methodology (RSM) using Design Expert 7 software. Phytotoxicity evaluation with Cicer arietinum revealed that seeds exposed to untreated dye effluents showed considerably lower growth, inhibited biochemical, and enzyme parameters with compared to those exposed to treated textile effluents. Thus this immobilized inexpensive technique could be used for removal of synthetic dyes present in textile wastewater.
•Pseudomonas mendocina was immobilized on waste and processed fly ash.•The immobilized Pseudomonas sp. was used to remove Reactive Yellow by integrated sorption and biodegradation approach.•Dye removal was found to be 88.51%, 92.62% and 98.72% for sorption, biodegradation and integrated approach.•Optimization of operating parameters of was done by response surface methodology.•Cicerarietinum seedlings exposed to untreated effluents showed poor growth, inhibited biochemical and enzyme parameters.
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For clean upgrading of heavy oil, catalytic treatment in supercritical water (SC-H2O) is known as an attractive green methodology. To gain quantitative and qualitative insights of ...heavy oil upgrading in SC-H2O, optimization of operating conditions was performed where higher heating value (HHV), low sulfur contents as well as low rate of coke formation are desirable. A series of experiments for upgrading the vacuum residue (VR) feed in SC-H2O were designed with response surface methodology (RSM) and performed in presence of formic acid and hematite iron oxide nanoparticles as hydrogen donor and catalyst, respectively. The key process parameters including temperature, water, formic acid, catalyst contents and reaction time were optimized by the mentioned statistical methodology. The proposed optimization model displayed an acceptable correlation between the predicted and experimental results. From the experimental results it was apparent the incorporation of hematite nanoparticles with SC-H2O and formic acid exhibited higher degree of light fraction product and low coke formation derived from oxygen vacancy and better catalyst reducibility in SC-H2O.
In recent years, heterogeneous electro-Fenton processes have gained considerable attention as an alternative to homogeneous processes. In this context, the aim of this study is the use of a ...commercial iron metal-organic framework (Fe-MOF), Basolite® F-300, as a base material for the design of a heterogeneous electro-Fenton treatment system for the removal of antipyrine. Initially, the catalyst was applied as powder in aqueous solution and three key parameters of the electro-Fenton process (pH, Fe-MOF concentration and current density) were evaluated and optimized by a Central Composite Design Face Centred (CCD-FC) using antipyrine removal and energy consumption as response functions. Near complete antipyrine removal (94%) was achieved under optimal conditions: pH 3, Fe-MOF 157.78 mg/L and current density 6.67 mA/cm2, obtaining an energy consumption of 0.29 W·h per mg of antipyrine removed. Later, two electrocatalysts (Fe-MOF functionalized cathodes), prepared by different Fe-MOF immobilisation approaches (composite of carbon black/polytetrafluoroethylene or by electrospinning on Ni foam), were synthesized. Their characterisation showed notable Fe-MOF incorporation into the material and favourable properties as electrocatalysts. Both Fe-MOF functionalized cathodes were evaluated in the removal of antipyrine at different pH (acidic and natural) and current density (27.78 and 55.56 mA/cm2), achieving in the best conditions removal levels around 80% in 1 h without any operational problems. In addition, several intermediates generated during the treatment were identified and their toxicity estimated. According to the obtained results, the degradation compounds have less toxicity than the parent compounds, confirming the effectiveness of the treatment.
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•Fe-MOF as heterogeneous catalyst for electro-Fenton process.•Optimization of key parameters for antipyrine degradation by Fe-MOF electro-Fenton.•Fe-MOF utility for the synthesis of electrocatalyst: Composite and electrospinning fibre.•Composite green synthesis showed great strength and high removal efficiency.•Fiber Fe-MOF exhibited good performance, high stability and durability.
This paper aims to fabricate and optimize eco-sustainable cement brick using different sizes of clay brick waste (CBW). The prime input factors of mixtures were clay brick powder (CBP) as a binder, ...fine-clay brick (FCB) as a fine aggregate, and coarse-clay brick (CCB) as a coarse aggregate, whereas the compressive strength was the main response of the generated eco-sustainable bricks. This was accomplished by utilizing the central composite design (CCD) and Response Surface Methodology (RSM) with Minitab-19. Twenty mixtures with CBW were generated and experimentally evaluated utilizing CCD concept in RSM. A multi-objective optimization approach was applied to obtain the optimum results for the input parameters. Based on an experimental program, the optimum mixtures were selected to investigate the physical and durability properties of the produced brick. The SEM test was also performed to determine the effect of the CBW particles on the microstructure of the brick. The life cycle assessment of mixtures is also performed in terms of global warming potential. The optimization showed that the input components CBP, FCB, and CCB had average optimum values of 21%, 0%, and 9.09%, respectively. The experimental results showed that employing CBW yields a durable and high freeze-thaw resistance of the eco-sustainable brick despite its high porosity and absorption. Furthermore, using cement brick with CBW particles is acknowledged as a more environmentally beneficial combination. The proposed models can speed up the process of mix design by using different sizes of brick waste to get the optimum eco-friendly cement brick properties.
In this article, we report the results of a robust model developed for estimating the thermal conductivity of a copper oxide-water nano-suspensions using Response Surface Methodology (RSM) at ...different temperatures and various mass fractions of nanoparticles. To increase the reliability, an ANOVA statistical approach was utilised to further identify the F-value and P-value of the model. To rank the operating parameters, a normal probability assessment was applied to the data to calculate the value of the noise and potential error distribution of the model. Results revealed that the developed model is robust, reliable and the achieved outcome is in a reasonable agreement with those data obtained by the experiments for the thermal conductivity of CuO (II)/water NF within 25 °C to 40 °C and mass concentrations of 1000 ppm to 4000 ppm. The values of R-squared (R2) and average absolute deviation (AAD%) were 0.9939 and 0.615%, respectively showing the accuracy and robustness of the established model. We also validated the RSM model by conducting further experiments. It was shown that the model can predict the thermal conductivity of the NF with less than 2% error.
•A model was developed for prediction of thermal conductivity of CuO-water.•Temperature and mass fraction were considered as input variables.•ANOVA technique was used to identify F-value and P-value of the model.•The obtained values of R2 and AAD% were 0.9939 and 0.615% for proposed model.
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