Process intensification in Desalination operation in mesoscale systems

Development of desalination technologies has been identified as vital to fulfilling future water demand. Directional solvent extraction is one of the promising membrane-less seawater desalination method. Membrane based desalination technologies incur a higher cost and are subjected to fouling after certain period of time of operation and needs regular maintenance and monitoring. It is believed that, overcoming these drawbacks is possible by working in the millimeter scale through the incorporation of pulsatile flow and air damper. This work presents a theoretical approach designed for a certain nominal length of an air damper, placed on the top of the extraction column, with the flow in the desalination unit being semi pulsatile combined with secondary pulsation generated due to air suspension during solvent extraction applied for desalination operation. Henceforth a theoretical approach based on the above stated parameters, it is found theoretically that with increase in flow pulsation amplitude and frequency the extracted salt concentration in solvent increases. The application of infra red radiation in preheating section with the help of a infrared heating device is the crucial part of DSE process, cooling is planned to achieve via a heat exchanger or atmospheric cooling. The total exergy and energy calculations will be conducted to see the energy requirement for the process. It is planned to calculate the salt separation efficiency of sea water (on the basis of WHO guidelines) to fresh water, alongwith flow rate and processing time.

A Novel Antibacterial Component and the Mechanisms of an Amaranthus tricolor Leaf Ethyl Acetate Extract against Acidovorax avenae subsp. citrulli

The aim of the present investigation was to determine the active ingredients in Amaranthus tricolor L. leaves and develop a biological pesticide. Organic solvent extraction, column chromatography, liquid chromatography, ODS-C18 reverse elution, Sephadex LH-20 gel filtration, H spectrum, and C spectrum were used to isolate the pure product for an assessment of the agricultural activity and bacteriostatic mechanisms. The results showed that the activity of the crude extract following carbon powder filtration was 1.63-fold that of the non-filtered extract. Further isolation was performed to obtain two pure products, namely, hydroxybenzoic acid (HBA) and benzo[b]furan-2-carboxaldehyde (BFC), and their molecular formulas and molecular weights were C7H6O3 and 138.12, and C9H6O2 and 146.12, respectively. Our study is the first to determine that HBA has bacteriostatic activity (MIC 125 μg/mL) and is also the first to isolate BFC from A. tricolor. The ultrastructure observation results showed that HBA caused the bacteria to become shriveled, distorted, and deformed, as well as exhibit uneven surfaces. After HBA treatment, 70 differentially expressed metabolites were detected in the bacteria, of which 9 were downregulated and 61 were upregulated. The differentially expressed metabolites were mainly strigolactones, organic acids and derivatives, fatty acids, benzene and substituted benzene derivatives, amino acids and associated metabolites, and alcohols and amines. Among all of the downregulated differentially expressed metabolites, MEDP1280 was the most critical, as it participates in many physiological and biochemical processes. The enrichment analysis showed that the differentially expressed metabolites mainly participate in tyrosine metabolism, biosynthesis of amino acids, cysteine and methionine metabolism, and arginine and proline metabolism. Additionally, HBA was found to disrupt cell membrane permeability and integrity, causing the leakage of substances and apoptosis. The physiological and biochemical test results showed that HBA could increase the pyruvate levels in bacteria but could decrease the activities of respiratory enzymes (malate dehydrogenase (MDH) and NADH oxidase) and antioxidant enzymes (superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX)). Inverse molecular docking was used to study the binding between HBA and respiratory and antioxidant enzymes. The results showed that HBA could bind to MDH, NADH oxidase, SOD, and GSH-PX, suggesting that these enzymes may be the effector targets of HBA. Conclusion: The optimal active ingredient in A. tricolor that can inhibit Acidovorax avenae subsp. citrulli was identified as HBA. HBA mainly disrupts the cell membrane, damages the metabolic system, and inhibits respiration and antioxidant enzyme activity to control bacterial growth. These results provide a reference for the further development of biological pesticides.

A Newly Developed Empirical Predictive Model for the Dispersed Phase (DP) Holdup in Rotating Disc Contactors

Newly novel developed correlations were derived to predict the dispersed phase (DP) holdup in a rotating disc contactor (RDC) extraction column. DP holdup is one of the significant parameters in the design of liquid–liquid contactors and for calculating their production capacity. Despite the availability of quite a large number of holdup prediction correlations for the RDC, most of these correlations are either general in nature or valid for a limited range of operating conditions. This study conducted an experimental and theoretical investigation of the RDC holdup under the influence of varying geometries, including variations in the dispersed phase distributor, speed of the disc, flow rate, and physical characteristics of the system. The analysis revealed that the holdup decreased with an increasing distributor hole diameter and increased with an increasing disc speed and total flow rate. The effect of the physical properties on the holdup was larger than the effect of the disc speed. Using the measurements of over 150 runs, two RDC column holdup predictive models were proposed and evaluated. The first correlation was derived in terms of the distributor hole diameter, operating parameters, system physical properties, and column geometry. The second correlation excluded the column geometry. These correlations, which consider the distributor hole inlet diameter in predicting the DP holdup for an RDC column, were presented for the first time in this study. The predictive capability of these correlations was evaluated via their standard deviation (SD) and mean average percentage error (MAPE). The respective SD and MAPE of the two correlations were 1.7 and 5.2% for the first correlation and 1.6 and 11.4% for the second.

Reversal of ABCG2/BCRP-Mediated Multidrug Resistance by 5,3′,5′-Trihydroxy-3,6,7,4′-tetramethoxyflavone Isolated from the Australian Desert Plant Eremophila galeata Chinnock

Multidrug resistance (MDR) is a major challenge in cancer treatment, and the breast cancer resistance protein (BCRP) is an important target in the search for new MDR-reversing drugs. With the aim of discovering new potential BCRP inhibitors, the crude extract of leaves of Eremophila galeata, a plant endemic to Australia, was investigated for inhibitory activity of parental (HT29par) as well as BCRP-overexpressing HT29 colon cancer cells resistant to the chemotherapeutic SN-38 (i.e., HT29SN38 cells). This identified a fraction, eluted with 40% acetonitrile on a solid-phase extraction column, which showed weak growth-inhibitory activity on HT29SN38 cells when administered alone, but exhibited concentration-dependent growth inhibition when administered in combination with SN-38. The major constituent in this fraction was isolated and found to be 5,3′,5′-trihydroxy-3,6,7,4′-tetramethoxyflavone (2), which at a concentration of 25 μg/mL potentiated the growth-inhibitory activity of SN-38 to a degree comparable to that of the known BCRP inhibitor Ko143 at 1 μM. A dye accumulation experiment suggested that 2 inhibits BCRP, and docking studies showed that 2 binds to the same BCRP site as SN-38. These results indicate that 2 acts synergistically with SN-38, with 2 being a BCRP efflux pump inhibitor while SN-38 inhibits topoisomerase-1.

Health-Promoting Properties of Borage Seed Oil Fractionated by Supercritical Carbon Dioxide Extraction

Borage (Borago officinalis L.) seed oil is an important source of γ–linolenic acid, which is normally used as a treatment against different pathologies. Since the fractionation of this interesting seed oil has many environmental, economic and biological benefits, two borage fractionation techniques after extraction with CO2 under supercritical conditions have been studied: precipitation in two cyclone separators and countercurrent extraction column. Both techniques have successfully collected free fatty acids in one fraction: (i) two separators set up in series obtained the highest concentration of free fatty acids in separator 2 at 90 bar/40 °C; (ii) when countercurrent extraction column was used, the acidity index of the raffinate stream was independent from the operating conditions (2.6 ± 0.5%). Furthermore, the composition of the fatty acids, as well as their antioxidant and cytotoxic activities, were determined. The profile of the fatty acids obtained by either of these two methods remained unaltered, so that the crude oil exhibited improved antioxidant and cytotoxic properties. All the extracts obtained in the two cyclone separators at the same pressure/temperature conditions displayed high tumouricidal activity against HL 60 promyelocytic leukaemia cells, even if the extracts at 50% concentration from separator 2 presented a lower inhibitory activity (IC50). The extracts from separator 2 at 90 bar/40 °C exhibited the highest anti-proliferative activity at low doses (IC50 of 0.3 μL/mL for the trypan blue exclusion test). To reach the lethal dose—IC50—with the product obtained through countercurrent column fractionation, a concentration of 2 μL/mL of crude borage oil raffinate was required.

Reducing energy costs during solvent regeneration at the tar deasphalting unit

For propane tar deasphalting units, a rather high energy intensity of the technological process is characteristic. In order to reduce it, an assessment was made of the possibility of reducing the steam consumption during the regeneration of propane from asphalt solution. The study was carried out using a Honeywell UniSim Design modeling system, in which a model of a propane tar deasphalting unit was formed. The Peng-Robinson method was used as a mathematical package for calculating the thermodynamic properties of the components of the fractions. The component composition of the feedstock is represented by oil fractions with boiling points from 405 to 616 °C. When carrying out a computational experiment, the following values of technological parameters were used: the tar consumption was 38.9 t / h, the ratio (propane: raw material) was (6.4: 1), the yield of deasphalted oil was about 30 wt%. The performed analysis of a typical scheme for the regeneration of propane from asphalt solution showed that in the process stream supplied to the feed of the stripping column K-6, there is already a sufficiently large amount of a vapor phase consisting practically of propane and traces of oil fractions. To efficiently use the energy of the flow without attracting additional energy costs, it is advisable to separate the gas and liquid phases before they enter the column K-6, that is, to include an additional separator in the technological scheme before it. The performed computational experiment showed that in the proposed version of the technological scheme, the steam consumption required for the release of propane decreases by 17.5%, which, accordingly, for the subsequent devices of the scheme, reduces the amount of water discharged into the sewage system. Optimization of technological modes of the stripping column K-6 provides a clear separation of propane, in the flow of which the content of bitumen fractions is 0.03 mol%, which makes it possible in industrial conditions to return the flow of propane to the feed of the extraction column. The proposed technological solution for propane recovery can be used in the processes of one- and two-stage tar deasphalting.

Molecular Imprinted of Nylon 6 for Selective Separation of Procaine by Solid-Phase Extraction

The study is based on the selective binding ability of the drug compound procaine (PRO) on a surface imprinted with nylon 6 (N6) polymer. Physical characterization of the polymer template was performed by X-ray diffraction and DSC thermal analysis. The imprinted polymer showed a high adsorption capacity to trap procaine (237 µg/g) and excellent recognition ability with an imprinted factor equal to 3.2. The method was applied to an extraction column simulating a solid-phase extraction to separate the drug compound in the presence of tinoxicam and nucleosimide separately and in a mixture of them with a recovery rate more than the presence of tinoxicam and nucleosimide separately and in a mixture of them with a recovery rate of more than 82%. Separation efficiency and excellent selectivity for procaine were ensured using a mixed solution injected into an HPLC technique consisting of a C18 column with a mobile phase mixture of water-acetonitrile (75:25) at pH 3.3. The study of drug control using an imprinted polymer with procaine compound showed that the complete drug release process is faster at pH1 in a maximum period of 80 min. The proposed method was successfully applied on some of the available pharmaceuticals, and it showed high selectivity for the separation of PRO, RE % was < 1.18, and RSD was less than 0.447.