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The United Nations, through its Sustainable Development Goals, have identified access to clean water as one of the challenges facing society. With reported global deaths exceeding 1 million annually linked to untreated water consumption, which is usually contaminated by pathogenic micro-organisms, further research continues in water disinfection. The direct generation of non-thermal plasma in water is a promising method for the inactivation of disease-causing bacteria present in the wastewater. This study explored the efficacy of plasma in the inactivation of different bacterial densities (4.0×104, 1.5×105, and 2.5×107 CFU/mL) using a 500 mL plasma batch reactor operating at atmospheric pressure. The plasma discharge was generated in water by a Technix-SR-10R-5000 high voltage direct current power supply in negative polarity with a set current of 0.45 A and a maximum pre-set ignition voltage of 9 kV. The electrodes used in the discharge was a copper material. A bacterial culture of Escherichia coli ATCC® 25922TM (E.coli) was used as a model for the direct plasma discharge. The study further investigated the contribution of copper ions (0.4 and 0.7 mg/L) released into the water during treatment by having two control reactors that were not exposed to plasma. The results show a complete inactivation at 180 seconds for the bacterial densities from 4.0×104 to 2.5×107 CFU/mL. The results from this study indicated the potential of a direct electric discharge in handling water source with high-bacteria densities.

Alkanolamine solutions are used in the industry worldwide to remove carbon dioxide and hydrogen sulfide from natural gas, but such technologies have disadvantages. This study aimed to investigate t...

Novel isothermal phase equilibrium data were measured, via the static analytic (SA) and static synthetic (SS) techniques, for the binary mixtures of tetrafluoromethane with either perfluoroheptane ...

The influence of different catalyst cobalt loadings on the C1-C3 hydrocarbon product yields and energy consumption in plasma-catalytic Fischer-Tropsch synthesis (FTS) was investigated from the standpoint of various reactor operating conditions: pressure (0.5 to 10 MPa), current (250 to 450 mA) and inter-electrode gap (0.5 to 2 mm). This was accomplished by introducing a mullite substrate, coated with 2 wt%-Co/5 wt%-Al2O3, 6 wt%-Co/5 wt%-Al2O3 or 0 wt%-Co/5 wt%-Al2O3 (blank catalyst), into a recently developed high pressure arc discharge reactor. The blank catalyst was ineffective in synthesizing hydrocarbons. Between the blank catalyst, 2 wt%, and the 6 wt% Co catalyst, the 6 wt% improved C1-C3 hydrocarbon production at all conditions, with higher yields and relatively lower energy consumption at (i) 10 MPa at 10 s, and 2 MPa at 60 s, for the pressure variation study, (ii) 250 mA for the current variation study, and (iii) 2 mm for the inter-electrode gap variation study. The inter-electrode gap of 2 mm, using the 6 wt% Co catalyst, led to the overall highest methane, ethane, ethylene, propane and propylene yields of 22 424, 517, 101, 79 and 19 ppm, respectively, compared to 40 ppm of methane and &lt, 1 ppm of C1-C3 hydrocarbons for the blank catalyst, while consuming 660 times less energy for the production of a mole of methane. Furthermore, the 6 wt% Co catalyst produced carbon nanotubes (CNTs), detected via transmission electron microscopy (TEM). In addition, scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX) and x-ray diffraction (XRD) showed that the cobalt catalyst was modified by plasma treatment.

An organic–inorganic functionalized nano-filler (CNC–TiO2), was prepared by loading titanium dioxide nanoparticles (TiO2) onto the crystalline nanocellulose (CNC) surface by using methacrylatesilane as cross-link agent in order to enhance compatibility between nanofiller and matrix (PMMA). Nanocomposite films (PMMA/CNC–TiO2) were prepared by free radical copolymerization of various amount (0–5 wt%) of functionalized nanofiller (CNC–TiO2) with methylmethacrylate (MMA) as main monomer, followed by solvent casting technique. The films were characterized using TEM, FTIR, FEG-SEM, and XRD, TGA, and UV–VIS spectroscopy. The results of TEM and FTIR confirmed the modification of CNC with TiO2 and the interaction between the CNC–TiO2 nanofiller and PMMA. FEG-SEM results showed a uniform dispersion of the nanofiller in the PMMA matrix whereas EDX confirmed the presence of TiO2 in the nanocomposite films. The effect of the nanofiller on the mechanical properties of PMMA was also investigated and the results showed significant improvement in tensile and modulus strengths with increasing amounts of nanofiller. In addition, TGA results demonstrated remarkable improvements in the thermal properties of the PMMA/CNC–TiO2 nanocomposite films UV results showed a response to UV absorbance due to incorporation of TiO2. Nanocomposite films can be beneficial for a variety of applications such as coating materials for windows, shelters, glazing, optical filters, and as hard packaging with UV-blocking properties.

As an extension of the pure component property estimation techniques that we have developed for normal boiling point, critical property data, vapor pressure, and liquid viscosity, a new group contr...

Isothermal vapor–liquid equilibrium data for five binary systems including 1,1,2,3,3,3-hexafluoro-1-propene and either 2,2,3,3,4,4,4-heptafluoro-1-butanol, cyclohexane, methylcyclohexane, 2-methylt...

In this work, the effect of a series of zwitterionic compounds (ZIs) aqueous solutions on the thermodynamic equilibrium and kinetic conditions of carbon dioxide hydrate formation is investigated. The hydrate dissociation conditions for (CO2 + ZI + water) systems are studied at different concentrations of ZI, viz. (0.10; 0.20, 0.30) mass fraction. The experiment was performed over a temperature range of T = (272–282) K and pressures range of p = (1.27–4.31 MPa) using a high pressure equilibrium cell. In this work the following ZIs: 4-(triethylammonio)butane-1-sulfonate [N222C4S], 4-(tributylammonio)-butane-1-sulfonate [N444C4S] and 4-(tributylphosphonio) butane-1-sulfonate [P444C4S] were investigated, therefore it was possible to determine the influence of alkyl chain length and the structure of the core atom on the kinetic behaviour of carbon dioxide gas hydrate formation. The results show that the gas hydrate phase equilibrium in the presence of zwitterionic compounds is shifted to higher pressures and lower temperatures so that the ZIs act slightly as a thermodynamic inhibitor of hydrate formation.

The solubility at solid–liquid equilibrium (SLE) has been determined for roflumilast (3-(cyclopropylmethoxy)-{N}-(3,5-dichloropyridin-4-yl)-4-(difluoromethoxy)benzamide) in eight solvents and marav...

Phase equilibrium conditions (dissociation data) for clathrate hydrates (gas hydrates) were studied for systems involving fluorinated refrigerants + water + single and mixed electrolytes (NaCl, CaCl2, MgCl2 and Na2SO4) at varying salt concentrations in the absence and presence of cyclopentane (CP). The ternary systems for (R410a or R507) + water + CP were performed in the temperature and pressures ranges of (279.8–294.4) K and (0.158–1.385) MPa, respectively. Measurements for {R410a + water + (NaCl or CaCl2) + CP} were undertaken at salt concentrations of (0.10, 0.15 and 0.20) mass fractions in the temperature and pressure ranges of (278.4–293.7) K and (0.214–1.179) MPa, respectively. The temperature and pressure conditions for the (R410a + water + Na2SO4) system were investigated at salt concentration of 0.10 mass fraction in range of (283.3–291.6) K and (0.483–1.373) MPa respectively. Measurements for {(R410a or R507) + water + mixed electrolytes NaCl, CaCl2, MgCl2} were undertaken at various salt concentrations of (0.002–0.15) mass fractions in the temperature and pressure ranges of (274.5–292.9) K and (0.149–1.119) MPa in the absence and presence of CP, for which there are no published data related to mixed salt and a promoter. The phase equilibrium measurements were performed using a non-visual isochoric equilibrium cell and the pressure-search technique. This study was focused on obtaining equilibrium data that can be utilized to design and optimize for water desalination process and the development of a Hydrate Electrolyte–Cubic Plus Association (HE–CPA) Equation of State based model. The results indicate hydrate dissociation pressure reduction/hydrate dissociation temperature increase up to ambient conditions in the presence of promoter (CP). The experimental results were then modelled. The modelling results are in good agreement with the measured hydrate dissociation data.

In this work we studied the applicability of two ionic liquids (ILs) for the separation of thiophene from octane, or hexadecane, as a model of the diesel stream. Experimental liquid-liquid phase equilibrium (LLE) data were obtained for four ternary systems {IL + thiophene + octane, or hexadecane} at T = 308.15 K and pressure p = 101 kPa. The ILs 1,3-dihydroxyimidazolium bis{(trifluoromethyl)sulfonyl}imide, [OHOHIM][NTf2] and 1-butyl-3-methylimidazolium trifluoromethanesulfonate, ([BMIM][CF3SO3]), [BMIM][OTf] were used to assess the desulfurization process. [BMIM][OTf] showed better selectivity than [OHOHIM][NTf2] in the extraction of thiophene from both, octane and hexadecane. The distribution ratio in all systems is acceptable in comparison with currently published data for different ILs. Chromatography analysis showed that the IL was not present in the octane, or hexadecane layer. This simplifies the process separating the solvent from the hydrocarbon layer. The data obtained have been correlated with the non-random two liquid (NRTL) model.

Hydrate dissociation conditions for the systems of CO2 + water + {NaCl or CaCl2 or MgCl2} + cyclopentane (CP) were investigated at various salt molalities of (1.041–4.278) mol·kg–1 in different tem...

Hydrate dissociation conditions are reported for the following systems: CO2 + tetra-n-butyl ammonium acetate (TBAA) + water, CO2 + tetra-n-butyl ammonium fluoride (TBAF) + water, CO2 + tetra-n-buty...

Isothermal vapor–liquid equilibrium measurements (pressure– temperature–liquid and vapor composition) were conducted for water (1) + propan-1-ol (2), n-hexane (1) + butan-2-ol (2), and n-hexane (1)...

In the present study, we reported the densities and excess molar volumes for the pure organic solvent mixtures such as {toluene (x1) + acetic acid (x2)}, {cyclohexane (x1) + acetic acid (x2)}, {toluene (x1) + 1-hexanol (x2)}, {toluene (x1) + 2-octanol (x2) } and {n-heptane (x1) + 1-hexanol (x2) } at temperature range from (288.15 to 343.15) K and at a pressure of 0.1 MPa. Excess molar volumes for these binary mixtures were calculated from the experimental density data and fitted to the Redlich-Kister polynomial equation to check the accuracy of experimental data. In addition, the interactions between the unlike molecules in the mixtures were confirmed by using the experimental results. We have also study the effect of temperature on molecular interactions between the molecules in the mixtures.

2,3-Pentanedione, acetaldehyde, and acetone are by-products found downstream in the sugar manufacturing process. 2,3-Pentanedione has various food and industrial-related uses, making it a product of interest. It can be recovered using extractive distillation recovery processes, whereby chemicals of similar boiling points are separated. Vapor–liquid equilibrium (VLE) measurements were conducted isobarically for the systems 2,3-pentanedione + {acetaldehyde or acetone} at 100, 150, and 200 kPa. Measurements were undertaken using a moderate pressure recirculating VLE still, capable of withstanding pressures up to 350 kPa. The measured VLE data were regressed using the gamma–phi (γ–φ) approach and the nonrandom two-liquid activity coefficient model, which displayed satisfactory representation of the system behavior. None of the binary systems exhibit azeotropic behavior. All the binary systems displayed a positive deviation from Raoult’s law.

In this study, CF4 hydrate dissociation conditions in the presence of different TBAB aqueous solutions with the concentrations of 0.05, 0.10, 0.20, and 0.3 mass fractions were experimentall...

Petroleum fractions, in particular heptane-plus fraction (C7+), are complex mixtures and measuring properties of hydrocarbon-plus fractions is difficult and time-consuming. In this study, the norma...

Isothermal phase equilibrium data were measured for the binary systems of tetrafluoromethane with either perfluorohexane or perfluorooctane to investigate the effect of carbon chain length of the solvent with regards to the solubility of tetrafluoromethane. Both the “static-analytic” and the “static-synthetic” methods were utilized to measure the high-pressure phase equilibrium data. Isothermal measurements were performed within the temperature range of (283.15–303.15) K and at pressures up to 11 MPa. Vapour pressure data for perfluorohexane and perfluorooctane were measured within the temperature range of (283.15–323.15) K. Additionally, isothermal vapour-liquid equilibrium data were measured for the binary system of carbon dioxide + n-hexane at 313.15 K; the data were utilized to validate the experimental method. The experimental data were modeled using the Peng-Robinson equation of state with the Wong-Sandler mixing rule and Non-Random Two-Liquid excess Gibbs energy model. The model provides a satisfactory representation of the experimental data within the measured temperature range.

In this study, modeling wax disappearance temperatures (WDTs) in hydrocarbon fluids is presented using three different soft computing approaches, namely feed forward artificial neural network; mult...

In this work, a thermodynamic consistency test method was used to investigate the reliability of isobaric experimental data on the sulfur content of hydrogen sulfide. The test was applied t...

New isothermal binary vapor–liquid equilibrium (VLE) systems of 1-pentanol + 2,2,4-trimethylpentane at 350.2, 360.2, and 370.2 K, methyl-tert-butyl-ether + 2,2,4-trimethylpentane at 307.2, 317.2, and 327.2 K, and methyl-tert-butyl-ether + 1-pentanol at 317.2 and 327.2 K were measured. The vapor–liquid equilibrium data were measured using a dynamic low pressure glass still. The experimental data were regressed using the γ–Φ approach (combined method) with the Wilson, NRTL, and UNIQUAC activity coefficient models for description of the liquid phase nonideality. The virial equation of state with the Hayden and O’Connell correlation for the second virial coefficient was used to describe the vapor phase nonideality. The system of 2,2,4- trimethylpentane + 1-pentanol exhibited a minimum boiling azeotrope. The methyl-tert-butyl-ether + (2,2,4-trimethylpentane/1-pentanol) systems showed positive deviation from Raoult’s law. The aforementioned activity coefficient models correlated the experimental data well. The ...

A new experimental setup based on the “static-synthetic” method was designed and commissioned for the measurement of solubility from vacuum to moderates pressures. The new apparatus and experimental method were extensively validated by measuring the solubility of carbon dioxide in three pure solvents, viz., n-hexane, n-methyl-2-pyrrolidone and 1-butyl-3-methylimidazolium tetrafluoroborate. New solubility data for carbon dioxide in hybrid solvents with different mixtures of 1-butyl-3-methylimidazolium tetrafluoroborate + n-methyl-2-pyrrolidone were measured at three temperatures, viz. (298.15, 313.15 and 323.15) K. Additionally, viscosity, density and sound velocity for binary mixtures of n-methyl-2-pyrrolidone + 1-butyl-3-methylimidazolium tetrafluoroborate were measured. The experimental phase equilibrium data were modelled using the Peng-Robinson equation of state and van der Waals mixing rule. In general, the solubility of carbon dioxide in the hybrid solvent was lower than the respective pure constituents. However, the hybrid solvent exhibited a significantly lower viscosity than the pure ionic liquid.