Search

Abstract: Physical properties, namely, density and refractive index of the ternary mixture consisting of 1-butyl-3-methylimidazolium tetrafluoroborate+monoethanolamine+water have been measured at temperature range from (303.15 to 353.15) K. The measured density and refractive index data were correlated as a function of concentration and temperature. The excess properties (excess molar volume and excess refractive indices) have been deduced from the experimental physical properties. [Copyright &y& Elsevier]

Abstract: The densities and refractive indices of ternary system of bis(2-hydroxyethyl)ammonium acetate ([bheaa])+monoethanolamine+water have been measured at T =(303.15 to 353.15) K. The measured density and refractive index data were correlated as a function of concentration and temperature. Excess molar volumes and refractive index deviations were calculated from the measured densities and refractive indices at each temperature. The excess molar volumes are negative and the refractive index deviations are positive at all conditions. [Copyright &y& Elsevier]

Abstract: Binary mixtures of 1-hexyl-3-methylimidazolium tetrafluoroborate [hmim][BF4] with N-methyldiethanolamine (MDEA) were prepared. Physical properties namely, density ρ, dynamic viscosity η and refractive index n D , of the binary mixtures were measured over a temperature range of 303.15K to 323.15K. The measured density and refractive index data were correlated as a function of concentration and temperature. Excess molar volumes V E were deduced from the experimental data. Excess molar volumes showed positive deviations over the entire range of concentrations and temperatures indicating a weak interaction between [hmim][BF4] and MDEA. Viscosity data for the binary mixtures were correlated by using the Kendall–Monroe model. [Copyright &y& Elsevier]

Abstract: Binary mixtures of 1-hexyl-3-methylimidazolium bis(trisfluoromethylsulfonyl)imide [hmim][Tf2N] with N-methyldiethanolamine (MDEA) were prepared. Physical properties namely, density ρ, dynamic viscosity η and refractive index n D , of the binary mixtures were measured over a temperature range of 303.15K to 323.15K. Excess molar volumes V E and excess refractive indices n D E were calculated from the experimental values and fitted to the Redlich–Kister equation. Viscosity values of binary mixtures were correlated by McAllister three body interaction model. Excess molar volumes showed positive deviations, whereas excess refractive indices showed negative values over the entire range of concentrations and temperatures. The coefficients of thermal expansion α, and excess coefficients of thermal expansion α E were also calculated from the experimental data. [Copyright &y& Elsevier]

The presence of dyes in contaminated water poses substantial dangers to the health of both humans and aquatic life. A process called precipitation polymerization was used to create unique cross-linked hexa-chlorocyclotriphosphazene-co-phenolphthalein (Hex-CCP-co-PPT) microspheres for the purpose of this research. Advanced methods such as X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential thermogravimetry (DTG) were used to characterise these microspheres. In a simulated solution, the performance of Hex-CCP-co-PPTs as a sorbent for removing MB dye was investigated, and the results showed an unprecedentedly high removal rate of 88.4% for MB. Temperature of 25 °C, a Hex-CCP-co-PPTs dose of 40 mg, an MB concentration of 20 ppm, an MB solution volume of 20 mL, a contact time of 40 min, and a pH of 9 were found to be the optimal experimental conditions. According to the results of the kinetic and adsorption analyses, the PSO and Langmuir adsorption models are the best ones to use. These models favour the chemi-sorption nature and mono-layered adsorption of MB in comparison to Hex-CCP-co-PPTs. Importantly, the thermodynamic analysis demonstrated that the process of removing MB by utilizing Hex-CCP-co-PPTs was endothermic and occurred spontaneously. These findings highlight the potential application of Hex-CCP-co-PPT microspheres in Algal Membrane Bioreactors (AMBRs) for the efficient and sustainable removal of dye from wastewater. This would contribute to the protection of ecosystems as well as the public's health. [Display omitted] • Synthesized novel Hex-CCP-co-PPTs microspheres. • Tested as efficient adsorbent for the uptake of MB dye. • Achieved maximum removal % of 88.4%. • PSO and Langmuir models were best fitted to data. • Thermodynamic study confirmed the feasibility of the adsorption process. [ABSTRACT FROM AUTHOR]

Synthesis of biodiesel from a non-edible source as Pistacia khinjuk seed oil via ultrasonic cavitation (UC) system is reported in this study. A heterogeneous catalyst sulphated tin oxide impregnated with silicon dioxide (SO 4 2- /SnO 2 –SiO 2 ) was employed during the transesterification reaction in an UC reactor. Parametric optimisation results revealed the maximum Pistacia khinjuk methyl ester (PiKME) yield was 88 wt.% at reaction time of 50 min, amplitude of 50%, catalyst amount of 3.5 wt.% and molar ratio of 13:1 (alcohol:oil). Performance of UC at optimised values was compared with mechanical stirring (MS). UC proved advantageous over MS with 3 times more time efficient. Hence, the superiority of UC over MS was established. About 3.2 fold higher reaction rate constant using UC (0.029 min −1 ) compared to MS (0.009 min −1 ). PiKME production via UC can potentially subsidise the overall cost of production by having 3.2 fold higher reaction rate constant than MS. PiKME met most of the fuel properties enlisted in EN14214 and ASTM D6751 standards. [ABSTRACT FROM AUTHOR]

Chemical interesterification of rubber seed oil has been investigated for four different designed orifice devices in a pilot scale hydrodynamic cavitation (HC) system. Upstream pressure within 1–3.5 bar induced cavities to intensify the process. An optimal orifice plate geometry was considered as plate with 1 mm dia hole having 21 holes at 3 bar inlet pressure. The optimisation results of interesterification were revealed by response surface methodology; methyl acetate to oil molar ratio of 14:1, catalyst amount of 0.75 wt.% and reaction time of 20 min at 50 °C. HC is compared to mechanical stirring (MS) at optimised values. The reaction rate constant and the frequency factor of HC were 3.4-fold shorter and 3.2-fold higher than MS. The interesterified product was characterised by following EN 14214 and ASTM D 6751 international standards. [ABSTRACT FROM AUTHOR]

Biodiesel by non-edible oils via ultrasonic cavitational technique offers a unique and novel approach towards waste management. This study aims to synthesis biodiesel from two non-edible sources namely; Salvadora alii oil and Thespesia populneoides oil. Transesterification was carried out in the presence of solid base calcium oxide catalyst while using an ultrasonic cavitation (UC) reactor. Parametric optimisation was conducted by central composite design and response surface methodology. Results revealed that optimum condition to obtain maximum yield (≈92 wt %) of Salvadora alii methyl ester was as; molar ratio = 10:1 (alcohol: oil), catalyst amount = 3 wt %, and amplitude = 50% in 30 min of reaction time. Similarly, optimum condition was found satisfactory to render maximum yield (≈88.6 wt %) of Thespesia populenoides methyl ester as molar ratio = 6:1 (alcohol: oil), catalyst amount = 3.5 wt %, and amplitude = 45% in 30 min of reaction time. At obtained optimised values UC was compared with mechanical stirring (MS). UC showed 3 fold higher reaction constants and 3 fold more time efficiency than MS. The superiority of UC over MS can be established. Biomass waste to biofuel can make biodiesel synthesis towards cleaner fuel. These results suggest that combination of non-edible oils and UC technology have the potential to make cleaner process. Most of the fuel properties were met the EN 14214 and ASTM D 6751 standards. [ABSTRACT FROM AUTHOR]

Development of cleaner biodiesel production related to hydrodynamic cavitation of methyl ester synthesis from sustainable waste cooking oil via alkali-catalysed transesterification is gaining importance due to considerable lower energy requirement and time. The effects of the oil to methanol molar ratio (1:4–1:7), catalyst concentration (0.5–1.25 wt %) and reaction temperature (50–65 °C) have been studied in a hydrodynamic cavitation and mechanical stirring system. Highest conversion of 98% was achieved under optimum conditions of 1:6 M ratio of oil to methanol, 1 wt % potassium hydroxide as alkali catalyst, 60 °C and 15 min reaction time. It has been observed that yield efficiency and reaction time were 833% higher and 600% shorter using hydrodynamic cavitation compared to mechanical stirring. Triglycerides conversion obeys pseudo-first order mechanism. The kinetic parameters of hydrodynamic cavitation and mechanical stirring were calculated, where the reaction rate constants were 0.238 and 0.031 min −1 , activation energies were 89.7 and 92.7 kJ/mol and the pre-exponential factors were 2.623 × 10 ​13 and 1.120 × 10 ​13 min −1 . Hydrodynamic cavitation was 1.8 fold more energy efficient and 4.6 fold lower feedstock used per produced product than mechanical stirring in biodiesel production. In conclusion, waste cooking oil methyl ester produced via hydrodynamic cavitation proved to be time saving and energy efficient compared to mechanical stirring. This makes the process more environmental friendly using hydrodynamic cavitation. [ABSTRACT FROM AUTHOR]

Biodiesel is envisaged as environmentally benign fuel due to its unique properties, such as biodegradability, renewability and non-toxicity. Its utilisation leads to the reduction of sulphur oxide and greenhouse gas emissions as it produces quite lower amounts of carbon and sulphur based gases in comparison to conventional fossil fuels. This paper is a review of the recent achievements of the cleaner intensification technologies for biodiesel production. Merits and limitations of the cleaner intensification technologies have been discussed. Mechanical stirring via transesterification is the most common and extensively utilised for biodiesel production. It involves the conversion of oil to glycerol and acid alkyl ester while employing methanol. However, this process has an inherent drawback of mass transfer resistance resulting in a lower reaction rate and higher production cost. Intensification technologies have become more attractive to overcome these aforementioned problems. In a bid to increase the cost competitiveness of biodiesel production compared to diesel fuel, process intensification has been studied for numerous biodiesel processing technologies. Many researchers have resorted to several intensification technologies namely; microwave, ultrasonic cavitation and hydrodynamic cavitation reactor to eliminate the mass transfer resistance of immiscible reactants. Once the mass transfer resistance is reduced, it may lead to a shorter reaction time and lower energy consumptions compared to mechanical stirring. Recent studies reveal that microwave and ultrasonic cavitation techniques are not yet completely feasible for biodiesel production at industrial scale. On the other hand, it was found that hydrodynamic cavitation offers a number of advantages over other intensification technologies. It shows good performance with respect to product yield, reaction time, energy consumption and product quality. Furthermore, it exhibits a sustainable mean for energy recovery from renewable oils. It was concluded that more studies are needed to extend the existing information of hydrodynamic cavitation for the design of the plate geometry with respect to the methyl ester conversion. This will help to develop a sustainable and industrially viable route for energy recovery from renewable oils. Yield efficiency in relation to the method followed the order: hydrodynamic cavitation > microwave > ultrasonic cavitation > mechanical stirring. [ABSTRACT FROM AUTHOR]

Producing sustainable biodiesel using non-edible feedstock via transesterification reaction assisted hydrodynamic cavitation technology is a viable way to offset fossil diesel usage. This technology has affirmative environmental impacts with lower energy consumption and the reaction time and offers a cleaner possibility. Methyl ester conversion has been observed at a different inlet pressure of 1–3.5 bar on different plate geometries in 50 L pilot hydrodynamic cavitation reactor. Orifice plate with 21 holes of 1 mm and inlet pressure of 3 bar found to be the optimal arrangement. Parametric optimisation used response surface methodology and found as alcohol to oil ratio of 6:1, catalyst loading of 1 wt.%, reaction time of 18 min and reaction temperature of 55 °C. About 5 fold shorter reaction time, 6.5 fold higher energy efficiency and 4.9 fold higher reaction rate constant using hydrodynamic cavitation compared to mechanical stirring. Hydrodynamic cavitation is concluded to be time saving and energy efficient process compared to mechanical stirring. This makes the process more environmental friendly using hydrodynamic cavitation. Most of the properties in rubber seed oil methyl ester were met the EN 14214 and ASTM D 6751 standards. [ABSTRACT FROM AUTHOR]

This study examines how environmental concerns impact the connectivity amid formal, informal control and performance based on data gathered from different 156 construction companies. The empirical outcomes illustrate that behaviour, outcome relationship between variables and clan control affirmatively affect performance on construction projects. However, self-control is unimportantly identified with project execution. This research uncovers that in construction projects, the adequacy of managerial control varies. The results further suggest that interior environmental concerns contrarily moderate the consequence of control of cleaner merchandise enactment during projects. However, external natural hazards emphatically direct the adequacy of project control, showing noteworthy and assorted roles played by different ecological dangers in the assembly of control and project execution. The interactive empirical outcomes between formal control and external environmental hazards are significantly related to project performance(t > 2, and p < 0.05) however the controlling impact of the inner environmental hazard on project control is relatively lower (β = 0.338, p > 0.05). The study concluded the least significant of all controller means towards the enactment of construction projects. Results showed that for complex projects, operative control approaches should be prioritised over ineffective control methods. • Production and environmental wastes are dependent in construction projects. • Internal environmental hazards undesirably control product developments. • External environmental risk positively moderates the control. • Environmental risks have a diverse moderating role between control and performance. • In construction projects, the effectiveness of marginal controls varies. [ABSTRACT FROM AUTHOR]