Piperazine Research Articles

Rigid twisted structured PA membranes for organic solvent nanofiltration via co-solvent assisted interfacial polymerization

Interfacial polymerization has always been a research hotspot for the preparation of polyamide (PA) membranes for molecular sieving. In previous reports, water-soluble amines (such as piperazine (PIP), m-phenylenediamine (MPD), etc.) were mostly used as monomers containing amino functional groups in the aqueous phase to conduct interfacial polymerization with 1,3,5-mesotribenzoyl chloride (TMC) in hexane, resulting in a dense PA film. However, this approach limits the diversity of polymer structures in PA films. To introduce water-insoluble 9,9-Bis(4-aminophenyl)fluorene (BAF) with a rigid twisted structure into interfacial polymerization, this study reports the interfacial polymerization of BAF in DMF/water solution with TMC in n-hexane. BAF-PA films with a larger free volume compared with MPD-PA were successfully prepared. The anomalous interfacial diffusion phenomenon was explained by the interfacial properties and molecular diffusion mechanism of the two-phase solvent and was confirmed by observing the microscopic morphology of the film. Since the structure of BAF-PA has a larger free volume, the BAF-PA film prepared by co-solvent interfacial polymerization has higher permeance to methanol (23.88 L m−2 h−1 bar−1). Meanwhile, it has more than 90% rejection of dyes with molecular weights of 585 Da and above. The large free volume PA film prepared with DMF/water mixed solvent exhibited excellent performance in organic solvent nanofiltration. This method also offers the possibility of introducing other water-insoluble amines into the interfacial polymerization to prepare PA films.

Carbon dioxide capture in a HiGee reactor with packing featuring controllable cross-sectional area

A rotating packed bed (RPB), as one of the typical HiGee reactors, has achieved extensive praise in CO2 capture fields. In this work, the novel mesh packings with controllable cross-sectional areas (CSAs) were applied to intensify the CO2 absorption process in an RPB, as well as combining with the blended aqueous amine solutions including diethylenetriamine (DETA) and piperazine (PZ). The gas pressure drop and CO2 absorption performance of various packings were investigated. Different operating conditions including rotational speed (400–2400 r/min), liquid flow rate (10–35 L/h), gas flow rate (900–2400 L/h), and CO2 molar fraction in gas inlet (2–12%) were considered. The results exhibited that the rise in gas pressure drop of concentric packing with constant CSA (CONC-9) relative to conventional coiled packing with increasing CSA (COII-9) was less than 10% on average. Meanwhile, the CO2 absorption efficiency of CONC-9 exceeded 17.1% on average than that of COII-9. For further comparison, the ratio of mass transfer coefficient to gas pressure drop in the wet RPB (KGa/△PW) was analyzed. The KGa/△PW of CONC-9 was 48.6% larger on average than that of COII-9. The average mass transfer coefficient and height of mass transfer unit of CONC-9 reached up to 16.7 kmol∙kPa−1∙m−3∙h−1 and 0.013 m, respectively. Overall, it is a viable way to adopt the packing with constant CSA to intensify the CO2 absorption in RPBs.

Asymmetric polyamide nanofilm with coordinated charge and nanopore, tuned by azlactone-based monomer to facilitate ion separation

Herein, we report an asymmetric polyamide (PA) nanofilm formed by using trimesoyl-[4,4-dimethyl-5(4H)-azlactone] (TMDMA) and trimesoyl chloride (TMC) as mixed organic phase. Of which, the sublayer is dendrimer porous layer and the top layer is a nanostriped interfacial polymerization (IP) PA nanofilm. Due to the higher acidity coefficient (pKa) of the hydrolyzed TMDMA, the resultant optimized asymmetric PA nanofilms have coordinated surface charge and narrowed mean effective nanopore. Experimental data demonstrate that the 0.1TMC/0.0125TMDMA–0.8 piperazine (PIP)-15 had a high MgCl2 rejection (97.41 ± 0.29 %) and a lower LiCl rejection (34.94 ± 1.02 %), and the corresponding water permeances were 343.6 ± 4.90 and 396.6 ± 4.98 kg m–2h−1 MPa−1, respectively. Moreover, a significantly enhanced Li+/Mg2+ selectivity was achieved, up to 58.7 under a LiCl/MgCl2 solution of 10.5 g L–1, while the related water permeance was 174.66 kg m–2h−1 MPa−1, which was superior to the most literature reported membranes and part of common commercial PA membranes (DK, DL and NF 90). Besides, the resultant membranes also showed an excellent sieving performance of Cl–/SO42– (141.1). This work demonstrates that the azlactone-based monomer enables to coordination of the inner structure of the IP PA nanofilm, thus facilitating ion sieving.

Regulation of interfacial polymerization process based on reversible enamine reaction for high performance nanofiltration membrane

The regulation of interfacial polymerization (IP) is the critical procedure for the preparation and industrialization of thin film composite (TFC) nanofiltration (NF) membranes. However, the IP control is still a huge challenge based on the extremely rapid reaction rate during the fabrication of the membrane. Herein, a new strategy was developed to modulate the IP process to increase the NF membrane performance. The aldehyde oxidized dextran (ODex) interlayer was deposited on the polysulfone ultrafiltration substrate, and the enamine would form between the secondary amines of aqueous phase monomer piperazine (PIP) and aldehyde groups of the ODex. Based on the by-products of IP, the enamine gradually decomposed reversibly in a hydrogen ion environment and the immobilized PIP was released and continued to react with organic phase monomer trimesoyl chloride (TMC). Accordingly, a thinner and exhibiting nanowire structures separation layer with fewer defects was obtained. The permeance of the optimal NF membrane with 0.7 wt% ODex interlayer deposition concentration could reach up to 208 ± 10.4 Lm−2h−1MPa−1, which was more than 2.5 times permeance of the ordinary NF membrane, and the rejection rate for Na2SO4 could reach 99.3 ± 0.3%. In addition, the mono- and divalent ion selectivity of the modified membrane was also greatly improved (αNaCl/Na2SO4 = 115). This study provides a new idea for the regulation of IP process, thereby suggesting a reasonable proposal for improving the performance of TFC NF membranes.

Synthesis, Docking Studies and Pharmacological Evaluation of Serotoninergic Ligands Containing a 5-Norbornene-2-Carboxamide Nucleus.

A new series of 5-norbornene-2-carboxamide derivatives was prepared and their affinities to the 5-HT1A, 5-HT2A, and 5-HT2C receptors were evaluated and compared to a previously synthesized series of derivatives characterized by exo-N-hydroxy-5-norbornene-2,3-dicarboximidenucleus, in order to identify selective ligands for the above-mentioned subtype receptors. Arylpiperazines represents one of the most important classes of 5-HT1AR ligands, and recent research concerning new derivatives has been focused on the modification of one or more portions of such pharmacophore. The combination of structural elements (heterocyclic nucleus, propyl chain and 4-substituted piperazine), known to be critical to the affinity to 5-HT1A receptors, and the proper selection of substituents led to compounds with high specificity and affinity towards serotoninergic receptors. The most active compounds were selected for further in vivo assays to determine their functional activity. Finally, to rationalize the obtained results, molecular docking studies were performed. The results of the pharmacological studies showed that Norbo-4 and Norbo-18 were the most active and promising derivatives for the serotonin receptor considered in this study.

Facile synthesis of nanofiltration membrane with asymmetric selectivity towards enhanced water recovery for groundwater remediation

Groundwater remediation by nanofiltration (NF) membrane is still hindered by low water recovery due to membrane scaling. In this study, a simple NaOH-promoted interfacial polymerization strategy was proposed to tailor the membrane asymmetric selectivity of calcium over sulfate ions to reduce scaling potential towards high water recovery. A 0.5 wt% NaOH was introduced during the interfacial polymerization of piperazine (PIP) and trimesoyl chloride on a polysulfone support. The promoted interfacial polymerization reduced polyamide defects for better rejection and enabled the use of lower PIP concentrations. Enhanced hydrolysis of the polyamide layer created a more negatively charged surface with larger pore sizes to achieve asymmetrical selectivity together with enhanced permeance. The water permeance of fabricated TFC-0.1 membrane with the aid of NaOH was 2.1 times that of commercial NF270 membrane, while exhibiting comparable perfluorooctanesulfonic acid rejections (>95%). This membrane also achieved ∼50% more water recovery than that of NF270 membrane under simulated gypsum scaling condition, owing to the selective passage of calcium (low rejection of 11.4 ± 0.6%). The exemplified strategy of NaOH-promoted interfacial polymerization is facile and readily scalable, which demonstrated strong potential towards high water recovery in groundwater remediation contaminated by emerging pollutants.

Fabrication of Thin Film Composite Membranes on Nanozeolite Modified Support Layer for Tailored Nanofiltration Performance.

Thin-film composite (TFC) structure has been widely employed in polymeric membrane fabrication to achieve superior performance for desalination and water treatment. In particular, TFC membranes with a thin active polyamide (PA) selective layer are proven to offer improved permeability without compromising salt rejection. Several modifications to TFCs have been proposed over the years to enhance their performance by altering the selective, intermediate, or support layer. This study proposes the modification of the membrane support using nanozeolites prepared by a unique ball milling technique for tailoring the nanofiltration performance. TFC membranes were fabricated by the interfacial polymerization of Piperazine (PIP) and 1,3,5-Benzenetricarbonyl trichloride (TMC) on Polysulfone (PSf) supports modified with nanozeolites. The nanozeolite concentration in the casting solution varied from 0 to 0.2%. Supports prepared with different nanozeolite concentrations resulted in varied hydrophilicity, porosity, and permeability. Results showed that optimum membrane performance was obtained for supports modified with 0.1% nanozeolites where pure water permeance of 17.1 ± 2.1 Lm−2 h−1 bar−1 was observed with a salt rejection of 11.47%, 33.84%, 94%, and 95.1% for NaCl, MgCl2, MgSO4, and Na2SO4 respectively.

Rapid transport of water and monovalent ions through ultrathin polyamide nanofilms for highly efficient mono/bivalent ions separation

Defect-free ultrathin polyamide nanofilms enable superior separation performance, which can be prepared by interfacial polymerization (IP) at free oil–water interface (also known as support-free IP). However, the current free IP methods usually suffer from complicated process, or complex equipment. Herein, an easily-manufactured plate-and-frame assembly for free IP was designed for more efficient fabrication of ultrathin membranes. Piperazine (PIP)-based negatively-charged NF membranes were fabricated by this method, combining with introduction of a rigidly-contorted spirobisindane monomer that simultaneously enhanced the mechanical strength, microporosity, and electronegativity of membrane. The resulting defect-free ultrathin membranes not only exhibit super-high Na2SO4 rejection (∼99.7 %), and allow rapid transport of water and monovalent ions, thus leading to a Cl-/SO42- selectivity of up to 240. Furthermore, the polymerization of acyl chloride and macromolecule polyethyleneimine (PEI) at free oil–water interface was also investigated. The resulting positively-charged ultrathin membranes show outstanding calculated monovalent/bivalent cation selectivity (54.8 for Li+/Mg2+, 43.2 for Na+/Mg2+), further demonstrating the effectiveness of ‘thickness reduction’ strategy to enhance ions selectivity. In addition, the cause of different surface charge properties for PIP and PEI membrane system was revealed by molecular simulation.

Robust polyamide-PTFE hollow fibre membranes for harsh organic solvent nanofiltration

Polymeric membranes have been extensively studied for organic solvent nanofiltration (OSN) but many fail to show sufficient chemical resistance in strong solvents like dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). This study focuses on harnessing the outstanding chemical resistance of polytetrafluoroethylene (PTFE), to develop polyamide-PTFE thin film composite (TFC) membranes that are resistant to such aprotic solvents. A defect-free polyamide thin film layer was successfully synthesized on the microfiltration PTFE hollow fibre substrates, overcoming challenges such as large and uneven pore size, and hydrophobicity of the PTFE substrates. A simple polydopamine (PDA) coating was carried out to improve the substrate’s hydrophilicity prior to the polyamide synthesis via interfacial polymerization (IP). Polyethyleneimine (PEI) and trimesoyl chloride (TMC) were used as the monomers and a two-time IP method was employed to obtain a defect-free polyamide coating. The synthesized membranes showed high acetonitrile (ACN) and DMF permeabilities of 7.94 and 3.70 lm−2h−1bar−1, respectively, with acid fuchsin (585 Da) rejections of > 90 %. The molecular weight cut-off (MWCO) of the membranes could be further reduced to ∼300 Da by the addition of piperazine (PIP) monomers. The membranes also showed excellent stability and performance in a 72-hour OSN test performed in DMF indicating their great potential in effective molecular separation in harsh solvents. This study demonstrates how a simple modification and coating technique can transform commercially available microfiltration PTFE hollow fibres into durable and high value OSN membranes.

Fabrication of Loose Nanofiltration Membranes with High Rejection Selectivity between Natural Organic Matter and Salts for Drinking Water Treatment.

Loose nanofiltration (LNF) membranes with a molecular weight cut-off (MWCO) of about 1000 Da and high surface negative charge density have great application potential for drinking water treatment pursuing high rejection selectivity between natural organic matter (NOM) and mineral salts. This study was conducted to exploit the novel method coupling non-solvent induced phase separation (NIPS) and interfacial polymerization (IP) for the preparation of high-performance LNF membranes. A number of LNF membranes were synthesized by varying the polyethersulfone (PES) and piperazine (PIP) concentrations in the cast solution for the PES support layer preparation. Results showed that these two conditions could greatly affect the membrane water permeance, MWCO and surface charge. One LNF membrane, with a water permeance as high as 23.0 ± 1.8 L/m2/h/bar, when used for the filtration of conventional process-treated natural water, demonstrated a rejection of NOM higher than 70% and a low rejection of mineral salts at about 20%. Both the mineral salts/NOM selectivity and permselectivity were superior to the currently available LNF membranes as far as the authors know. This study demonstrated the great advantage of the NIPS–IP method for the fabrication of LNF membranes, particularly for the advanced treatment of drinking water.

Distinct impact of substrate hydrophilicity on performance and structure of TFC NF and RO polyamide membranes

Substrate properties have profound impacts on the structure and performance of both thin-film composite (TFC) nanofiltration (NF) and reverse osmosis (RO) polyamide (PA) membranes. Some studies have previously investigated the impact of substrate hydrophilicity on PA formation and TFC membrane performance. However, the observed phenomena and explanations remain contradictory in literature. Herein, we performed interfacial polymerization (IP) reactions of both piperazine (PIP)-trimesoyl chloride (TMC) and m-phenylenediamine (MPD)-TMC systems on substrates with different hydrophilicity. We found that the TFC RO membrane showed higher water permeance and NaCl rejection on the relatively hydrophobic substrate, while the TFC NF membrane favored the relatively hydrophilic substrate. The critical importance of interfacial degassing and local monomer concentration was highlighted to dissect the distinct impact of substrate hydrophilicity. For the MPD-TMC system, interfacial nanobubble generation was inhibited because of the decreased local MPD concentration and heat production for the more hydrophilic substrates, resulting in a decrease in the roughness feature and compromised water permeance of RO membranes. In contrast, interfacial degassing was not a dominant mechanism in the PIP-TMC system due to the slower reaction rate of PIP-TMC than MPD-TMC. Consequently, the PA layer of NF membrane became thinner and looser when the substrate became more hydrophilic, resulting from the diluted local PIP concentration. Our study unveils the fundamental relationship among substrate hydrophilicity, PA structure, and separation performance of both TFC NF and RO PA membranes, providing important guides on their design and synthesis.

Comprehensive mass transfer analysis of CO2 absorption in high potential ternary AMP-PZ-MEA solvent using three-level factorial design.

Mass transfer of CO2 absorption in 2-amino-2-methyl-1-propanol (AMP)-piperazine (PZ)-monoethanolamine (MEA) was statistically investigated in terms of overall mass transfer coefficient ([Formula: see text]) and CO2 removal percentage. The parameters of interest were lean solvent flux (A), rich gas flux (B), CO2 loading in the lean solvent (C), and ratio of the sampling height to the total column height [Formula: see text] (D). From ANOVA, A was the most impactable parameter on both responses with three-quarters of the overall contribution. Regarding the three-level factorial design, a second-order polynomial increasing trend of [Formula: see text] was observed as C and/or D increased. Additionally, [Formula: see text] linearly increased as A increased but was not affected by B. On the other hand, the CO2 removal percentage linearly increased as A and/or D increased but linearly decreased as B and/or C increased. Surface analysis suggested the optimum condition for both responses at a high level of A, low level of B, low level of C, and middle level of D. In this work, D was statistically investigated and included in the predictive correlation for [Formula: see text] for the first time. The main advantage of the proposed correlation over the recently reported correlations was that it did not require a measurement of CO2 partial pressure along the column height. For each amine component in the blend, (i) AMP played a positive key role in cyclic capacity and solvent regeneration duty, (ii) PZ enhanced transfer rate, and (iii) MEA elevated total amine concentration. As a result, 1.5:1.5:3 was recommended due to (i) elevations of 68.2% [Formula: see text], 14% CO2 removal percentage, 15.1% absorption capacity, and 66.7% cyclic capacity and (ii) reduction of 50% regeneration duty compared with 5M MEA. With respect to the other literature-reported solvents, AMP-PZ-MEA is very competitive in terms of transfer coefficient, cyclic capacity, and solvent regeneration heat duty.

MODELING POLARIZATION CURVE IN AN AQUEOUS CARBONATED SOLUTION OF PIPERAZINE

A polarization curve model is developed for carbon steel in an aqueous carbonated solution of piperazine (PZ). This model has been used to generate the polarization curve and control the parameters relevant to the corrosion rate of carbon steel in the PZ-CO2-H2O system. Electrochemical experiments are carried out for carbon steel corrosion measurements at 40 °C and different carbon dioxide partial pressure using the potentiodynamic polarization technique. The Vapor-liquid Equilibrium and the electrochemical corrosion models are the two main models used in this study. The electrolyte-NRTL equilibrium model was utilized to calculate the chemical species concentration at the carbon steel-solution interface in the PZ-CO2-H2O system. The findings of speciation were then applied to the generation of polarization curves and the prediction of the corrosion rate of the carbon steel surface. The results of the polarization curves modeling were compared to the experimental curves developed in MatLab software 2013a. Comparing experimental and modeled polarization curves and corrosion rate reveals excellent agreement.

Nanofiltration Membranes with Crumpled Polyamide Films: A Critical Review on Mechanisms, Performances, and Environmental Applications

Nanofiltration (NF) membranes have been widely applied in many important environmental applications, including water softening, surface/groundwater purification, wastewater treatment, and water reuse. In recent years, a new class of piperazine (PIP)-based NF membranes featuring a crumpled polyamide layer has received considerable attention because of their great potential for achieving dramatic improvements in membrane separation performance. Since the report of novel crumpled Turing structures that exhibited an order of magnitude enhancement in water permeance ( Science 2018, 360 (6388), 518-521), the number of published research papers on this emerging topic has grown exponentially to approximately 200. In this critical review, we provide a systematic framework to classify the crumpled NF morphologies. The fundamental mechanisms and fabrication methods involved in the formation of these crumpled morphologies are summarized. We then discuss the transport of water and solutes in crumpled NF membranes and how these transport phenomena could simultaneously improve membrane water permeance, selectivity, and antifouling performance. The environmental applications of these emerging NF membranes are highlighted, and future research opportunities/needs are identified. The fundamental insights in this review provide critical guidance on the further development of high-performance NF membranes tailored for a wide range of environmental applications.

Ultrathin polyamide nanofiltration membrane prepared by triazine-based porous organic polymer as interlayer for dye removal

Separation membrane with high flux is generally encouraged in industrial application, because of the tremendous needs for decreasing membrane areas, usage costs and space requirements. The most effective and direct method for obtaining the high flux is to decrease membrane thickness. Polyamide (PA) nanofiltration membrane is conventionally prepared by the direct interfacial polymerization (IP) on substrate surface, and results in a thick PA layer. In this work, we proposed a strategy that constructing triazine-based porous organic polymer (TRZ-POP) as the interlayer to prepare the ultrathin PA nanofiltration membranes. TRZ-POP is firstly deposited on the polyethersulfone substrate, and then the formed TRZ-POP provides more adhesion sites towards PA based on its high specific surface areas. The chemical bonding between terminal amine group of TRZ-POP and the amide group of PA further improves the binding force, and strengthens the stability of PA layer. More importantly, the high porosity of TRZ-POP layer causes the higher polymerization of initial PA owning to the stored sufficient amino monomer; and H-bonding interaction between amine groups of TRZ-POP and piperazine (PIP) can astrict the release of PIP. Thus, IP process is controlled, and the thinnest thickness of prepared PA layer is only < 15 nm. As expected, PA/TRZ-POP membrane shows a more excellent water flux of 1414 L·m−2·h−1·MPa−1 than that of the state-of-the-art nanofiltration membranes, and without sacrificing dye rejection. The build of TRZ-POP interlayer develops a new method for obtaining a high-flux nanofiltration membrane.

Positively Charged Poly(Piperazinamide) Nanofiltration Membranes for the Fast Removal of Metal Ions

AbstractPositively charged nanofiltration (NF) membranes with high perm‐selectivity are highly desired to remove divalent cations such as Ca2+ and Mg2+ ions to ensure the safety of domestic and industrial water supply. In this work, a poly(piperazinamide) NF membrane with a positively charged surface is fabricated via the surfactant‐assembly regulated interfacial polymerization (SARIP) of piperazine (PIP) and 1,3,5‐trimesoyl chloride (TMC). The surfactant assembly can accelerate PIP monomer into the hexane to react with TMC monomer, thus reducing the difference in the trans‐interface diffusion of PIP and the diffusion of TMC in hexane, forming an interfacial polymerization with a stoichiometric characteristic. By tuning the concentration ratio of PIP and TMC, a positively charged poly(piperazinamide) NF membrane will be achieved. At the same time, utilizing the superior hydrophilicity of bacterial cellulose nanofibers nanofilm, a crumpled poly(piperazinamide) active layer is successfully constructed, resulting in a permeating flux up to 22 L m−2 h−1 bar−1 and simultaneously with a MgCl2 rejection &gt;96%. The performance of this positively charged poly(piperazinamide) NF membrane is superior to most other positive NF membranes for the removal of divalent cations so far.

Multiscale energy reduction of amine-based absorbent SO2 capture technology: Absorbent screening and process improvement

The high total regeneration energy consumption (Qtot) limits the industrial application of amine-based absorbent SO2 capture technology, and regeneration energy consumption can be divided into desorption reaction heat (Qdes), latent heat consumption (Qlat) and sensible heat consumption. This work focused on developing an energy-efficient SO2 capture technology through amine-based adsorbent screening and process improvement, in which desorption reaction heat, being the internal cause of high regeneration energy consumption, was only related to the type of adsorbent. An absorbent screening method was established with SO2 absorption capacity (α) and desorption reaction heat values as indicators. The screening results showed the functional relationship of Qdes-α for five organic diamines ethylenediamine (EDA), piperazine (PZ), N-hydroxyethylpiperazine (HEP), N, N'-dihydroxyethylpiperazine (DIHEP), and N-hydroxyethyl-N'-hydroxypropylpiperazine (HEHPP)): according to αEDA > αPZ > αHEHPP > αHEP > αDIHEP, Qdes(EDA) > Qdes(PZ) > Qdes(HEHPP) > Qdes(DIHEP) > Qdes(HEP). The latent heat consumption and sensible heat consumption were related to process configuration, and N-methyldiethanolamine (MDEA), EDA, PZ and HEP were screened as amine-based absorbers for process modeling. The energy analysis showed that the order for regeneration energy consumption of the four absorbents followed Qtot(MDEA) > Qtot(EDA) > Qtot(PZ) > Qtot(HEP), and the energy distribution calculations showed that latent heat consumption had the largest proportion in regeneration energy consumption. Three improved processes (the rich-split, the lean-flash heat pump and the top-steam heat pump processes) were designed to recover the energy available in the system. Compared to the conventional process, the top-steam heat pump case could greatly reduce the regeneration energy consumption, and the Qtot values of the four absorbents (MDEA, EDA, PZ, and HEP) in the top-steam heat pump case were 4.28 GJ·t−1 SO2, 3.10 GJ·t−1 SO2, 3.13 GJ·t−1 SO2 and 3.68 GJ·t−1 SO2, respectively. According to technical and economic analyses, the top-steam heat pump case under the PZ absorbent system had the most potential for the flue gas SO2 capture process.

Novel tertiary amine-based biphasic solvent for energy-efficient CO2 capture with low corrosivity

A tertiary amine-based biphasic solvent, N,N-dimethylethanolamine (DMEA)/piperazine (PZ)/N-butanol (n-BuOH)/H2O, was proposed for energy-efficient CO2 capture. Low energy-consuming deprotonation dominated the CO2 desorption reaction, resulting in a Qrxn as low as 1.17 GJ/t CO2. Combining with the significantly reduced Qsen and Qlatent due to phase separation, an extremely low regeneration energy consumption (1.59 GJ/t CO2) was obtained, which was only 39.8% of 30 wt% MEA, and lower than most of reported biphasic solvents. The addition of n-BuOH not only induced the phase separation, but also reduced the activation energy of the reaction between DMEA and CO2. It worked together with PZ to improve the inherent slow absorption rate of DMEA to a comparable value with 30 wt% MEA. Although a decreased CO2 loading in the total solution was detected because the addition of n-BuOH reduced the equilibrium constant from 3.82 E+2 to 8.98 E+1, this biphasic solvent still achieved high CO2-rich loading (4.23 mol/L), large desorption capacity (3.77 mol/L), and superior desorption efficiency (89.1% at 393.15 K) owing to the good phase separation and desorption properties. In addition, the corrosion rate of CO2-rich phase was only 1.35% of CO2-loaded MEA. This research provided a promising alternative absorbent for CO2 capture.

The nematode serotonin-gated chloride channel MOD-1: A novel target for anthelmintic therapy

Anthelmintics are used to treat human and veterinary parasitic diseases and to reduce crop and livestock production loss associated with parasitosis. The free-living nematode Caenorhabditis elegans, a model system for anthelmintic drug discovery, has a serotonin (5-HT)-gated chloride channel, MOD-1, which belongs to the Cys-loop receptor family and modulates locomotory and behavioral functions. Since MOD-1 is unique to nematodes, it is emerging as an attractive anthelmintic drug target, but details of MOD-1 function are unclear. Here, we revealed novel aspects of MOD-1 function from the molecular level to the organism level and identified compounds targeting this receptor, which may provide new directions for anthelmintic drug discovery. We used whole-cell current recordings from heterologously expressed MOD-1 to show that tryptamine (Tryp), a weak partial agonist of vertebrate serotonin type 3 (5-HT3) receptors, efficaciously activates MOD-1. A screen for modulators revealed that GABAergic ligands piperazine (PZE) and muscimol reduce 5-HT-elicited currents, thus identifying novel MOD-1 allosteric inhibitors. Next, we performed locomotor activity assays, and we found 5-HT and Tryp rapidly decrease worm motility, which is reversible only at low 5-HT concentrations. Mutants lacking MOD-1 are partially resistant to both drugs, demonstrating its role in locomotion. Acting as an antagonist of MOD-1, we showed PZE reduces the locomotor effects of exogenous 5-HT. Therefore, Tryp- and PZE-derived compounds, acting at MOD-1 through different molecular mechanisms, emerge as promising anthelmintic agents. This study enhances our knowledge of the function and drug selectivity of Cys-loop receptors and postulates MOD-1 as a potential target for anthelmintic therapy.

Development of Antifouling Thin-Film Composite/Nanocomposite Membranes for Removal of Phosphate and Malachite Green Dye.

Nowadays polymer-based thin film nanocomposite (TFN) membrane technologies are showing key interest to improve the separation properties. TFN membranes are well known in diverse fields but developing highly improved TFN membranes for the removal of low concentration solutions is the main challenge for the researchers. Application of functional nanomaterials, incorporated in TFN membranes provides better performance as permeance and selectivity. The polymer membrane-based separation process plays an important role in the chemical industry for the isolation of products and recovery of different important types of reactants. Due to the reduction in investment, less operating costs and safety issues membrane methods are mainly used for the separation process. Membranes do good separation of dyes and ions, yet their separation efficiency is challenged when the impurity is in low concentration. Herewith, we have developed, UiO-66-NH2 incorporated TFN membranes through interfacial polymerization between piperazine (PIP) and trimesoyl chloride (TMC) for separating malachite green dye and phosphate from water in their low concentration. A comparative study between thin-film composite (TFC) and TFN has been carried out to comprehend the benefit of loading nanoparticles. To provide mechanical strength to the polyamide layer ultra-porous polysulfone support was made through phase inversion. As a result, outstanding separation values of malachite green (MG) 91.90 ± 3% rejection with 13.32 ± 0.6 Lm−2h−1 flux and phosphate 78.36 ± 3% rejection with 22.22 ± 1.1 Lm−2h−1 flux by TFN membrane were obtained. The antifouling tendency of the membranes was examined by using bovine serum albumin (BSA)-mixed feed and deionized water, the study showed a good ~84% antifouling tendency of TFN membrane with a small ~14% irreversible fouling. Membrane’s antibacterial test against E. coli. and S. aureus. also revealed that the TFN membrane possesses antibacterial activity as well. We believe that the present work is an approach to obtaining good results from the membranes under tricky conditions.