Aqueous Solutions Of Piperazine Research Articles

Predictive modeling of CO2 solubility in piperazine aqueous solutions using boosting algorithms for carbon capture goals

Carbon dioxide (CO2) is the main greenhouse gas that drives global warming, climate change, and other environmental issues. CO2 absorption using amine solvents stands out as one of the most well-known industrial technologies of CO2 capture. However, accurate prediction of CO2 absorption in aqueous amine solutions under different operating conditions is crucial for designing an efficient amine scrubbing system in power plants. In this work, CO2 solubility in aqueous piperazine (PZ) solutions was modeled using 517 experimental data points covering a temperature range of 298 to 373 K, PZ concentration of 0.1 to 6.2 mol/L (M), and CO2 partial pressure of 0.03 to 7399 kPa. To this end, four robust machine learning algorithms, including gradient boosting with categorical features support (CatBoost), light gradient boosting machine (LightGBM), extreme gradient boosting (XGBoost), and adaptive boosting decision trees (AdaBoost-DT) were utilized. Among the developed models, the CatBoost model presented the highest accuracy with an overall determination coefficient (R2) of 0.9953 and an average absolute relative error of 2.36%. Sensitivity analysis revealed that CO2 partial pressure had the greatest influence on CO2 absorption in aqueous PZ solutions, followed by PZ concentration and temperature. Moreover, CO2 partial pressure positively influenced CO2 absorption in aqueous PZ solutions, while PZ concentration and temperature exhibited negative effects. Finally, the leverage technique indicated that both the experimental data bank used for modeling and the model’s estimates were statistically acceptable and valid showing only 8 points (∼1.5% of total data) as possible suspected data.

Open access, thermodynamically consistent, electrolyte NRTL model for piperazine, AMP, water, CO2 systems on Aspen Plus

This study developed a comprehensive, open-access, thermodynamically consistent, validated vapour-liquid equilibrium model for CO2 absorption into aqueous solutions of piperazine (PZ) activated 2-amino-2-methyl-1-propanol (AMP) on Aspen Plus. This solves a two-decade-old problem of inconsistent specification of PZ, and lacking AMP/PZ, thermodynamic models on Aspen Plus, supporting robust process modelling of AMP/PZ-based CO2 capture systems, considered the contemporary benchmark. The model coverage is wide: total amine concentrations from 30 wt% to 50 wt%, AMP/PZ mole ratios from 0.46 to 23.1, CO2 loadings from 0.04 to 1.07 mol CO2/mol amine, and temperatures from 20 °C to 160 °C. The significance lies in the model’s innovative treatment of the zwitterion PZH+CO2–, leading to accurate VLE predictions and closed charge balances. Absolute average relative deviations (AARD) are 16.6 % to 22.3 % for CO2 partial pressure predictions and 6.3 % to 7.7 % for absorption heats. Gibbs-Helmholz and flash calculated absorption heats consistently compare within 1.5 % to 7.0 %, signalling the model’s thermodynamic consistency.

Electrochemical behavior of smooth gold in aqueous solutions of piperazine and N1,N2-dimethylethane-1,2-diamine

Electrochemical behavior of smooth gold in aqueous solutions of piperazine and N1,N2-dimethylethane-1,2-diamine

Guanidinium manipulated interfacial polymerization for polyamide nanofiltration membranes with ultra-high permselectivity

Polyamide (PA) nanofiltration (NF) membranes with excellent permeability and selectivity have always been the ultimate pursuit of desalination technology. Herein, we present a guanidinium manipulated interfacial polymerization strategy to develop guanidyl-integrated PA NF membranes with ultra-high permselectivity. A nylon microfiltration membrane is utilized as the support to conduct spatial-temporal regulation of amine monomers along with controllable diffusion reaction. Through introducing 1,3-diaminoguanidine (DAG) or triaminoguanidine (TAG) into the aqueous piperazine solution, the free volumes of PA membranes could be well modulated at the sub-angstrom scale. Consequently, the TAG-integrated PA membrane exhibited high water permeance of 33.1 LMH bar−1 and superior Na2SO4 rejection of 99.2%. Meanwhile, this membrane achieved outstanding anion sieving capability (Cl−/SO42− ∼ 343) and nearly 100% tetracycline removal, which is superior to the “state-of-the-art” PA NF membranes. The DAG-integrated PA membrane attained ultra-high water permeance of 46.5 LMH bar−1 due to its relatively large free volume. In addition, the nylon composite PA membranes displayed desirable anti-pressure and organic solvent-resistant abilities. This study provides a convenient and scalable preparation strategy for highly permselective NF membranes, which holds great application potential in desalination and resource recovery.

Energy-efficient carbon dioxide capture using piperazine (PZ) activated EMEA+DEEA water lean solvent: Performance and mechanism

Water vapor contained in industrial waste gas will be accumulated in non-aqueous amine solvents when used for CO2 capture and subsequently affect capture efficiency. While Piperazine (PZ) could be considered as an activator of the solution. Hence the effect of different contents of water and PZ added into the non-aqueous amine solvents on the CO2 capture performance has been investigated. 13C NMR has been used to identify the compounds present in aqueous CO2-rich amine solvents to characterize the mechanism of reactions. The energy consumption using 2-(ethylamino)ethanol (EMEA) water-lean amine solvent and aqueous monoethanolamine (MEA) solution was tested and compared on lab-scale, and further a comprehensive evaluation in a bench-scale pilot plant has been performed; It was found that the regeneration efficiency of the solution was reduced by approximately 10% when the water content was 10 wt%. The addition of PZ can recover the regeneration efficiency of the solvent to 94.2%. And its energy consumption was reduced by about 45% compared to the aqueous MEA solution in a 72-hour continuous absorption-desorption experiment. The results demonstrated that the aqueous PZ solution could improve the regeneration efficiency by involving in the proton transfer process. This work has proven that the blend of water-lean amine solvent and PZ is a novel, energy-efficient absorbent for CO2 capture.

Preparation and characterization of a novel polyethersulfone nanofiltration membrane modified with Bi2O3 nanoparticles for enhanced separation performance and antifouling properties

The nanofiltration membranes were prepared based on Poly Ether Sulfone (PES) via the phase inversion method in the study. The membranes were subsequently fabricated through interfacial polymerization between Piperazine (PIP) and Trimesoyl Chloride (TMC) monomers. Consequently, the fabricated membranes were modified using Bismuth Oxide (Bi2O3) nanoparticles. Bi2O3 nanoparticles were dispersed in PIP aqueous solution (Nano Bi2O3-TFCaq) and in TMC organic solution (Nano Bi2O3-TFCorg) by two different procedures to investigate the effect of nanoparticles and the manufacturing process on membrane properties. The prepared membranes were characterized via Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) analysis, atomic force microscopy (AFM), tensile strength, and zeta potential analysis. The tests were performed to check the surface structure, chemical composition, and hydrophilicity of the modified membrane. Also, the salt and BSA rejection rate of the membranes were investigated. Besides, both modified membranes were used to remove Hydrochlorothiazide (HCTZ) drug as the target pollutant. Eventually, it was concluded that the novel Nano Bi2O3-TFC membranes could be so useful in wastewater treatment.

Incorporating Ag@RF core-shell nanomaterials into the thin film nanocomposite membrane to improve permeability and long-term antibacterial properties for nanofiltration

Ag@resorcinol-formaldehyde resin (Ag@RF) core-shell nanomaterials were prepared by Stöber method, and introduced into polyamide (PA) selective layer of thin-film nanocomposite (TFN) membranes through the interfacial polymerization (IP) process. Due to the abundant hydroxyl groups on the surface and suitable particle size, Ag@RF nanoparticles (Ag@RFs) could be uniformly dispersed in the piperazine aqueous solution and participate in the IP process to precisely regulate the microstructure of the PA selective layer. The resulting “crater structure” and irregular granular structure enlarged the permeable area and contributed to the surface hydrophilicity. For the nanofiltration application, the water flux of TFN membrane modified by Ag@RFs to Na2SO4 solution reached 150 L·m−2·h−1 which was 87.5% greater than TFC, and salt rejection was maintained. The antibacterial efficiency of the prepared TFN membrane on E. coli reached 99.6% in the antibacterial experiment. In addition, due to the special structure of Ag@RFs, the TFN membrane also showed an expected slow-release capability of Ag+, allowing for long-term anti-biofouling properties. This work demonstrates that Ag@RF core-shell nanoparticles with high compatibility of organic nanoparticles and antibacterial properties of Ag nanoparticles could be used as promising nanofillers for designing functional nanofiltration TFN membranes.

Innate connection between salts on preparation and separation performance of Thin-film Poly (piperazinamide) composite membrane

ABSTRACT The development of thin-film polyamide composite membranes is a revolutionary aspect of the history of membrane science. ‘Wet phase inversion’ and ‘interfacial polymerization’ are two important steps in preparing thin-film polyamide composite (TFC) membranes. Poly (piperazinamide) TFC membranes make a strong pitch for greater regulation of selective passage of mono- and bi-valent salts. The result is a resounding success for the salt separation. In this work, an attempt has been made to study the consequence of salt in gelation bath and interfacial polymerization regarding the behavior of TFC membranes to separate salts from water. The water flux through the polysulfone (Ps) membrane decreases (776.15 LMH to 179.56 LMH) with TDS (salt up to 20000 mg/L. The increase in salt concentration in the aqueous phase (5 to 500 mg/L) of the interfacial reaction influences the salt separation abilities of the TFC membranes. It increases salt separation (Na2SO4 8–9% NaCl 4–6%) by adding 500 mg/L NaCl in piperazine-aqueous solution in different base membranes (Ps-I to Ps-VII). The defluoridation performances of the membranes in accordance with the similar trend as SO4 =. The separation follows the sequence: SO4 = > F− > Cl−. The rejection difference (between Pip-IC and Pip-VIIC) is highest as TDS increases, i.e., TDS: 500 mg/L. The flux reduction is similar (i.e., 30%) as in the case of SO4 = and Cl−.

Ultrapermeable polyamide nanofiltration membrane formed on a self-constructed cellulose nanofibers interlayer

Improving the water permeance of polyamide nanofiltration (NF) membranes without the simultaneous loss of rejection is highly desired but remains a challenge. In this work, we prepared an ultrapermeable polyamide NF membrane containing an in-situ-formed cellulose nanofibre (CN) interconnected network film between a polyamide active layer and ultrafiltration (UF) membrane support through direct addition of the CN to a piperazine aqueous solution for interfacial polymerization. Such in-situ-formed CN interlayer with high porosity can provide a large number of channels for water transport. Compared with the polyamide active layer directly supported by the UF support, the polyamide active layer supported by the CN interlayer can contribute a more effective area for water permeation. Consequently, the polyamide NF membrane exhibited a pure water permeance up to 35.7 L m−2 h−1 bar−1 while maintaining salt rejection to Na2SO4 of >97%. This permeance is 2.5 times greater than that of the membrane without the CN interlayer.

Enhancement of kinetic rates of CO2 in aqueous solutions of piperazine and methyldiethanolamine with addition of sulfolane

AbstractMeasurements of kinetics rates of CO2 in aqueous solutions of methyldiethanolamine (MDEA), piperazine (PZ), and mixtures of (MDEA + PZ), (PZ + sulfolane) and (MDEA + sulfolane) were carried out using the stopped flow technique, and reported in terms of pseudo‐first‐order rate constants (k0). When possible, the second‐order reaction rate constants (k2) were regressed from the data. Experiments were performed over new concentration ranges of (10–60), (200–800), (200–800, 10–40), (10–40, 10–200), and (200–800, 10–200) mol/m3 for the above‐mentioned five systems, respectively, and at temperatures varying from (298.15–313.15 K). When sulfolane was added to the amine solution, pseudo‐first‐order rate constants in the mixed solvents were higher than in aqueous MDEA and PZ solutions at all temperatures. The kinetic rates were highest at 298.15 K and decreased at higher temperatures for aqueous (MDEA + sulfolane) solutions but increased with temperature for aqueous (PZ + sulfolane) systems. Reaction orders for both PZ and MDEA were practically one at all sulfolane concentrations and temperatures. The base catalysis mechanism was used to regress very well data for aqueous MDEA and (MDEA + sulfolane + water) and the termolecular mechanism was used for (PZ + sulfolane + water) system. Both the zwitterion and termolecular models were able to fit the experimental data for the aqueous PZ system well. Finally, the termolecular and a hybrid model based on the combination of the Zwitterion and base catalysis mechanisms were able to successfully correlate the experimental data for the mixed aqueous (MDEA + PZ) systems.

Optimization and modeling of carbon dioxide absorption into blended sulfolane and piperazine aqueous solution in a stirrer reactor

Optimization and modeling of carbon dioxide absorption into blended sulfolane and piperazine aqueous solution in a stirrer reactor

Postcombustion CO2 Capture: A Comparative Techno-Economic Assessment of Three Technologies Using a Solvent, an Adsorbent, and a Membrane

This work compares three postcombustion CO2 capture processes based on mature technologies for CO2 separation, namely, (i) absorption using an aqueous piperazine solution, (ii) adsorption using Zeolite 13X in conventional fixed beds (either vacuum swing adsorption or temperature swing adsorption), and (iii) multistage membrane separation using a polymeric material (with CO2/N2 selectivity of 50 and permeability for CO2 of 1700 GPU). All three capture plants are assumed to be retrofitted to a generic industrial CO2-emitting source with 12% CO2 v/v (with 95% relative humidity at the inlet temperature and pressure of 30 °C and 1.3 bar, respectively) to deliver CO2 at 96% purity. In the cases of adsorption and membranes, the flue gas is dried before feeding it to the CO2 capture unit. In a first step, the capture processes (i.e., components and design parameters) are optimized based on their technical performance, defined through process exergy requirement and plant productivity; exergy–productivity Pareto fronts are computed for varying CO2 recovery rates. Second, the economic performance of the processes is assessed through a cost analysis. Estimates of CO2 capture costs are provided for each process as a function of the plant size and CO2 recovery rate. The comparative assessment shows that, although the adsorption- and membrane-based processes analyzed may become cost competitive at the small scale (i.e., below sizes of 100 tons of flue gas processed per day) and low recovery rates (i.e., below ca. 40%), the absorption-based process considered is the most cost-effective option at most plant sizes and recovery rates.

Measurement of the Absorption Rates of Carbon Dioxide in Aqueous Solutions of Piperazine and Sulfolane Using the Stopped-flow Technique

With the accelaration of the exploitation of natural gas reservoirs, the efficient removal of contaminants such as CO2, H2S, RSH, and COS is becoming of critical importance. In recent years, there is a growing interest in using amine blends or mixed solvents instead of a single amine for gas sweetening processes. Mixed solvents composed of a chemical solvent and a physical solvent take advantage of the benefits of both physical and chemical absorptions. The study of the absorption kinetics of the mixed solvent are necessary for designing and optimizing the process for removal of CO2 from natural gas, synthesis gas, or reformer gas. As a physical solvent, Sulfolane has excellent stability and low corrosiveness, in addition to a high capability for CO2 absorption. Sulfinol is a comercially successful process used in more than 200 plants and based on the use of Sulfolane as a physical solvent and either Diisopropanolamine (DIPA) or Methyldiethanolamine (MDEA) as chemical solvents. Mixed Sulfolane-based solvents have recently been proposed for post-combustion CO2 capture. In this study, the reaction kinetics of carbon dioxide (CO2) in aqueous solutions of aqueous piperazine (PZ) and an aqueous mixed solvent of (PZ + Sulfolane) were measured using the stopped flow technique resulting in the meaurement of observed pseudo-first-order rate constants (k0) allowing for the calculation of the second-order reaction rate constants (k2). The experiments were carried out over) concentration ranges of (10 to 60) for PZ, and (10 to 40, 10 to 200) (mol/m3) for PZ and Sulfolane, respectively and temperatures ranging from (298.15 to 313.15) K. Results show that the kinetic rates of the mixed solvent (PZ + Sulfolane + Water) were higher than those in aqueous PZ at all temperatures. The reaction kinetics in aqueous mixed solents of (PZ + Sulfolane) in reaction with CO2 increase with increasing temperature and concentration. The Termolecular mechanisms correlated the aqueous mixed systems of (PZ + Sulfolane) successfully. The reaction kinetics increased with the increase in temperature and concentration. The addition of Sulfolane to aqueous PZ resulted in increased absorption rates. Thus, the mixed solvent of PZ, Sulfolane and water can be considered an attractive alternative to aqueous amines for the enhancement of CO2 capture.

A combined interfacial polymerization and in-situ sol-gel strategy to construct composite nanofiltration membrane with improved pore size distribution and anti-protein-fouling property

Pore size distribution is crucial for the application of nanofiltration membrane in size-selective separation of industrial fluids. In this work, a novel combined interfacial polymerization (IP) and in-situ sol-gel strategy was proposed to fabricate composite nanofiltration membrane with narrow pore size distribution. Aqueous solution of piperazine and polyvinyl alcohol (PVA) was employed to perform interfacial polymerization with organic solution of trimesoyl chloride and tetraethyl orthosilicate (TEOS) on porous support. The non-reactive additive TEOS within the interfacially synthesized selective separation layer was then employed to perform sol-gel. The space-limited hydrolysis and condensation of TEOS molecules and their chemical bonding with PVA molecules were confirmed by analyzing membrane physico-chemical property and were found to be effective in tuning mean pore diameter, narrowing the pore size distribution and thus enhancing membrane perm-selectivity. Compared to those of membrane PA1 with similar mean pore size fabricated by only IP technique, the water permeability and rejection ratio of PEG1000 to raffinose (RPEG1000/Rraffinose) of membrane PA-TEOS0.5 fabricated by combined IP and sol-gel technique were higher by 25.0 and 20.1%, respectively. Moreover, static adsorption and dynamic deposition tests using aqueous bovine serum albumin solution proved that in-situ sol-gel process could endow the membrane with better protein fouling resistance.

In-situ synthesis of PA/PVDF composite hollow fiber membranes with an outer selective structure for efficient fractionation of low-molecular-weight dyes-salts

A polyamide/poly(vinylidene fluoride) composite hollow fiber membrane (HFM) was designed by in situ interfacial polymerization (IP) during the fiber spinning process. Using a piperazine aqueous solution as the bore fluid and a dual-bath coagulation, the PA outer layer was formed via IP of the PIP in the bore fluid and TMC in the second reactive bath during phase inversion process. Chemical structure, membrane morphology and surface property were characterized by using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscope (XPS), scanning electron microscope (SEM), and zeta potential. The effects of several parameters involved in the membrane fabrication (e.g., piperazine concentration, bore fluid flow rate, residence time and heat treatment temperature) on the morphology and performance of resultant composite HFMs were investigated. The composite HFM showed a performance that is comparable favorably with conventional nanofiltration membranes in terms of showed water permeability (10.2 L/m2·h·bar), high rejection to dyes (i.e., 100% for CR and EBT, 99.99% for RhB and MB, 98.3% for MO) and low salt rejections (NaCl 6.2%). Moreover, the newly developed composite HFM showed good stability and flux recovery with simple water rinsing for treatment of simulated textile wastewater. This work is expected to provide a new approach to designing composite HFMs for the treatment and reuse of textile wastewater.

Numerical simulation of CO2 chemical absorption in a gas-liquid bubble column using the space-time CESE method

Abstract In this study, numerical simulation of the removal process of CO2 using aqueous solutions of piperazine (PZ) in a bubble column has been done. The main focus of this work is to investigate the applicability of the space-time conservation element and solution element (CESE) method for the numerical solution of the coupling of hydrodynamics, mass transfer and chemical reactions. The reactive absorption process has been investigated by means of experiments and numerical simulation. A two-dimensional computational fluid dynamics (CFD) model in the Eulerian framework has been used to describe the gas-liquid system. To obtain the numerical solution, the CESE method based on a uniform rectangular mesh has been implemented by developing a computer code. Experimental study and CFD simulations have been carried out at different conditions of CO2 partial pressure (20 and 36 kPa) and solution concentration (0.1, 0.3 and 0.5 M). The simulation results were in reasonable agreement of 5.226 % and 4.575 % with the experimental values for gas holdup and mass transfer flux, respectively. The comparisons prove that the CESE method can be considered as a proper numerical method for the simulation of complex multiphase flows due to its simplicity, accuracy and low computational costs.

Modeling and validation of carbon dioxide absorption in aqueous solution of piperazine + methyldiethanolamine by PC-SAFT and E-NRTL models in a packed bed pilot plant: Study of kinetics and thermodynamics

A pilot plant with a closed cycle of the absorption/desorption process has been taken into account for the simulation of carbon dioxide (CO2) capture by piperazine (PZ) + methyldiethanolamine (MDEA) solution using Aspen Plus rate-based model with all design and operational parameters such as the hydraulic specifications of absorber and stripper as well as inlet flue gas conditions which are present in a commercial gas-fired burner for heating houses. Metal FLEXIPAC 250Y has been considered as the packing type to apply the model to the proposed correlations on Aspen Plus for calculation of flooding and pressure drop. In order to simulate the process, a new property package has been developed by electrolyte non-random two-liquid (E-NRTL) model and perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state which are used for the calculation of activity and fugacity coefficients respectively. The model has been compared with some experimental data e.g. CO2 absorption efficiency and CO2 loading and demonstrated good agreement with them.

Monitoring the Interfacial Polymerization of Piperazine and Trimesoyl Chloride with Hydrophilic Interlayer or Macromolecular Additive by In Situ FT-IR Spectroscopy.

The interfacial polymerization (IP) of piperazine (PIP) and trimesoyl chloride (TMC) has been extensively utilized to synthesize nanofiltration (NF) membranes. However, it is still a huge challenge to monitor the IP reaction, because of the fast reaction rate and the formed ultra-thin film. Herein, two effective strategies were applied to reduce the IP reaction rate: (1) the introduction of hydrophilic interlayers between the porous substrate and the formed polyamide layer, and (2) the addition of macromolecular additives in the aqueous solution of PIP. As a result, in situ Fourier transform infrared (FT-IR) spectroscopy was firstly used to monitor the IP reaction of PIP/TMC with hydrophilic interlayers or macromolecular additives in the aqueous solution of PIP. Moreover, the formed polyamide layer growth on the substrate was studied in a real-time manner. The in situ FT-IR experimental results confirmed that the IP reaction rates were effectively suppressed and that the formed polyamide thickness was reduced from 138 ± 24 nm to 46 ± 2 nm according to TEM observation. Furthermore, an optimized NF membrane with excellent performance was consequently obtained, which included boosted water permeation of about 141–238 (L/m2·h·MPa) and superior salt rejection of Na2SO4 > 98.4%.

Porous Zr-Based Metal-Organic Frameworks (Zr-MOFs)-Incorporated Thin-Film Nanocomposite Membrane toward Enhanced Desalination Performance.

Four different thin-film nanocomposite (TFN) membranes were prepared by adding different concentrations of porous Zr-metal-organic frameworks (MOFs) (UiO-66 and UiO-66-NH2) to piperazine aqueous solution (aqueous phase) or 1,3,5-benzenetricarbonyl trichloride-n-hexane solution (organic phase) by interfacial polymerization. The main purpose is to study the specific effects of different addition methods and addition amounts of nanoparticles on the structure and performance of the TFN membranes by interfacial polymerization. All four TFN membranes exhibited a higher water permeability while maintaining high salt rejection compared to thin-film composite membrane. On the one hand, the TFN membranes behave differently, which are prepared by adding the same kind of nanoparticles to the aqueous phase or organic phase, respectively. The TFN membrane prepared by adding 0.2 w/v% UiO-66 to the organic phase had a high water flux of 87.86 L m-2 h-1, compared to 46.31 L m-2 h-1 of the membrane prepared by adding 0.3 w/v% UiO-66 in the aqueous phase. This is due to the fact that UiO-66 greatly slows the interfacial polymerization rate when UiO-66 is added to the organic phase, resulting in a thinner and wider-aperture polyamide thin-film layer, reducing the water transmission resistance during filtration. Therefore, it is more economical by adding nanoparticles to organic phase than aqueous phase under the same filtering effect. On the other hand, different nanoparticles can also cause differences in performance and structure of the TFN membranes even in the same preparation manner. TFN membrane with UiO-66-NH2 in the aqueous phase has higher water permeance than the one with UiO-66 in the aqueous phase, owing to the good hydrophilicity of the amino group, which improves the water dispersibility of UiO-66-NH2 so that the TFN membrane is more uniform. In addition, UiO-66-NH2 slows down the process of interface polymerization, making the membrane more porous. The monomers in the aqueous phase and organic phase can be adsorbed in the pores of Zr-MOFs, which makes the interfacial polymerization occur both in the pores and on the surface of the pores. Thus, the compatibility between the polyamide and MOFs was enhanced and less defects were formed in the thin-film layer, resulting in a high salt rejection even when the concentration of Zr-MOFs increased. This is the first time to explain that polyamide membrane has not obvious salt rejection attenuation with increasing porous material content using pore adsorption reaction monomer principle. Also, the Zr-MOFs-based TFN membrane exhibited good heat resistance and antifouling property. This work shows that porous Zr-MOFs nanomaterials have significant advantages in the development of nanofiltration membranes with high water flux and rejection.

Efficient hybrid modeling of CO2 absorption in aqueous solution of piperazine: Applications to energy and environment

Carbon dioxide (CO2) considerably contributes to the greenhouse effects and consequently, to the global warming. Thus, reduction of CO2 emissions/concentration in the atmosphere is an important goal for various industrial and environmental sectors. In this research work, we study CO2 capture by its absorption in mixtures of water and piperazine (PZ). Experimental techniques to obtain the equilibrium data are usually costly and time consuming. Thermodynamic modeling by Equations of State (EOSs) and connectionist tools leads to more reliable and accurate results, compared to the empirical models and analytical modeling strategies. This research work utilizes Genetic Programming (GP) and Genetic Algorithm-Adaptive Neuro Fuzzy Inference System (GA-ANFIS) to estimate the solubility of CO2 in mixtures of water and piperazine (PZ). In both methods, the input parameters are temperature, partial pressure of CO2, and concentration of PZ in the solution. A total number of 390 data points is collected from the literature and used to develop GP and GA-ANFIS models. Assessing the models by the statistical methods, both models are found to acceptably predict the CO2 solubility in water/PZ mixtures. However, the GP exhibits a superior performance, compared to GA-ANFIS; the values of Average Absolute Relative Error (AARD) are 5.3213% and 9.7143% for the GP and GA-ANFIS models, respectively. Such reliable predictive tools can assist engineers and researchers to effectively determine the key thermodynamic properties (e.g., solubility, vapor pressure, and compressibility factor) which are central to design and operation of the carbon capture processes in a variety of chemical plants such as power plants and refineries.