Separation Method Research Articles

A novel green cloud point extraction-based switchable hydrophilicity solvent method for antimony separation and quantification from various bottled beverages by HGAAS

Herein, switchable hydrophilicity solvent (SHS) was used as a synergistic reagent in the cloud point extraction (CPE) protocol to increase the procedure’s efficiency and sensitivity. At room temperature, the CPE-SHS method was created for the fast and accurate extraction of antimony from a variety of drinks. Hydride generation atomic absorption spectroscopy (HGAAS) was used to antimony detection in various samples following the CPE-SHS protocol. The N,N-dimethylamine (DMA), TritonX-100, and p-tert-butyl-tetrakis[(diethylamide)methoxy]tetrathiacalix[4]arene (BTDMTA) were used as a SHS, surfactant, and chelation reagent, respectively. This procedure’s criteria for validation have been identified, including linearity (0.01–700 µg/L), accuracy, precision, limit of detection (LOD = 0.007 µg/L), limit of quantification (LOQ = 0.023 µg/L), enhancement factor (EF = 160), and matrix influence. This approach was validated using certified reference material. The environmentally friendly practices of this method were assessed using recent tools like Complex Modified GAPI (ComplexMoGAPI) software, Analytical GREEnness Calculator (AGREE) software, Blue Applicability Grade Index (BAGI) software, and Sample Preparation Metric of Sustainability (SPMS) program.

Emerging ZnO Semiconductors for Photocatalytic CO2 Reduction to Methanol.

Carbon recycling is poised to emerge as a prominent trend for mitigating severe climate change and meeting the rising demand for energy. Converting carbon dioxide (CO2) into green energy and valuable feedstocks through photocatalytic CO2 reduction (PCCR) offers a promising solution to global warming and energy needs. Among all semiconductors, zinc oxide (ZnO) has garnered considerable interest due to its ecofriendly nature, biocompatibility, abundance, exceptional semiconducting and optical properties, cost-effectiveness, easy synthesis, and durability. This review thoroughly discusses recent advances in mechanistic insights, fundamental principles, experimental parameters, and modulation of ZnO catalysts for direct PCCR to C1 products (methanol). Various ZnO modification techniques are explored, including atomic size regulation, synthesis strategies, morphology manipulation, doping with cocatalysts, defect engineering, incorporation of plasmonic metals, and single atom modulation to boost its photocatalytic performance. Additionally, the review highlights the importance of photoreactor design, reactor types, geometries, operating modes, and phases. Future research endeavors should prioritize the development of cost-effective catalyst immobilization methods for solid-liquid separation and catalyst recycling, while emphasizing the use of abundant and non-toxic materials to ensure environmental sustainability and economic viability. Finally, the review outlines key challenges and proposes novel directions for further enhancing ZnO-based photocatalytic CO2 conversion processes.

Diagnosing multiple faults in rotating machinery using empirical mode decomposition and blind source separation methods

It is a challenging task to accurately diagnose multiple faults in a rotating machinery. In this paper, the authors have used empirical mode decomposition (EMD) and blind source separation (BSS) methods for this purpose. A portable rotating machinery setup is made in the laboratory and faults such as bearing inner and outer race faults, angular misalignment are created into it. The vibration data is collected using SPM made LEONOVA DIAMOND(r) FFT analyzer and processed using CONDMASTER RUBY(r) and MATLAB(r) softwares. Firstly, wavelet transform is applied to the signal to denoise it. After this, EMD is implemented to decompose the signal into different intrinsic mode functions (IMFs). After preprocessing these IMFs using the principal component analysis (PCA), BSS is used to extract fault-related information from the IMFs. A comparison of the results obtained from EMD and PCA-BSS is also presented in the paper. Keywords: Rotating machinery, Multiple faults, Vibration data, Wavelet transform, Empirical mode decomposition, Blind source separation, Principal component analysis.

A positive semi definite tensor factorization method for separation of non stationary noise sources

In the aircraft industry, noise mitigation has emerged as an increasingly pressing issue, underscoring the critical importance of advancing our understanding of noise origins within turbofan engines. This paper presents the application of Positive Semi Definite Tensor Factorization (PSDTF), a potential method for the analysis of engine static tests conducted with far-field microphone arrays. By extending the capabilities of Non-negative Matrix Factorization (NMF), PSDTF offers an effective algorithm for source separation. Leveraging on cross spectral matrices to harness phase information across microphones, this approach aims at separating the contributions of several noise sources, avoiding the need for a precise acoustical model (sound propagation, source directivity, etc.). Experimental findings on a controlled experiment demonstrate the superiority of PSDTF over conventional NMF variants in achieving higher-quality source separation.

Biotechnological methods for separation of pigs pancreas glands protein substances with membrane technologies

The pancreas gland (PG) is a secondary product of livestock processing; it contains a wide range of biologically active compounds. The purpose of this article is to analyze the efficiency of technological approaches for pancreas gland extraction with the help of trehalose and a glycine-proline mixture aimed for recovery and separation of the gland’s protein-peptide compounds. The extraction was conducted with 0.9% NaCl, 0.9% NaCl, with addition of 0.5 M trehalose (0.9% NaCl-0.5 M trehalose) and 0.9% NaCl with addition of 1% glycine and 0.1 M L-proline (0.9% NaCl-1% Gly-0.1M Pro), the ratio of pancreas gland to extractant was equal to 1:5. The concentration of the protein in the supernatants after their extraction was measured by the biuret reaction in a semi-automatic biochemical analyzer Biochem SA. The proteomic composition of the extracts and the native pancreas gland was assessed by one-dimensional Laemmli electrophoresis in a 12.5% polyacrylamide gel and by two-dimensional O’Farrell electrophoresis. When determining the intensity of the protein fractions, it was noted that the methodology of separation of protein-peptide mixtures extracted from the pigs pancreas gland with the extractant 0.9% NaCl-1% Gly-0.1M Pro, ensured the higher extraction of the proteins in comparison with the method of 0.9% NaCl-0.5 M trehalose. Notwithstanding the fact that application of amino acids (glycine and proline) mixture provided for a greater yield of proteins from the extract into the diafiltrate, the experiments in vitro showed that the diafiltrate obtained though trehalose featured higher activity. This may be explained by the fact that after dialysis removal of trehalose from the protein fraction with a molecular weight of less than 50 kDa, its residual quantities were still sufficient to prevent proteins aggregation and, as a consequence, the biological activity of the extracted proteins was preserved, while in the diafiltrate obtained through amino acids mixture where numerous protein aggregates were detected by 2-DE. This study allowed testing the biotechnological methodics on pig pancreatic tissues aimed to intensifying the extraction and separation of protein compounds. The results of the study are important for development of methodological approaches to obtaining the targeted substances for their further utilizing for various purposes.

Research on Magnetic Field of Permanent Magnet Rolls Arranged Periodically in Circumferential—Axial Direction

The separation of non-magnetic non-ferrous metals such as copper and aluminum from scrapped automobiles is a critical area of research due to the increasing number of end-of-life vehicles. Traditional eddy current separation methods have limitations, particularly in handling large-sized broken copper and aluminum parts. This paper proposes a novel magnetic roller model featuring a circumferential–axial periodic arrangement of permanent magnets. This study explores the external magnetic field distribution of this new roller design by constructing an equivalent current model, solving magnetic scalar potential equations, and employing simulation tools. The findings indicate that the new magnet array enhances both the magnetic field strength and the range of the external magnetic field, leading to improved separation efficiency of large-sized metal fragments. The results provide a theoretical basis for advancing the separation technology of large-sized broken copper and aluminum parts in scrapped automobiles, offering potential improvements in the recycling of non-ferrous metals from end-of-life vehicles.

Rotating and stationary sound sources separation method based on MCB

Traditional beamforming methods do not effectively separate the mixed field of sound sources for different rotational speeds. The coexistence of these sources often manifests out-of-focus sources (for instance, stationary sources appearing with a rotational focus), thereby blurring the beamforming outcomes. Most existing algorithms for segregating rotational different speed sources employ a virtual rotating array utilizing ring arrays. However, due to the constant microphone spacing, the acoustic imaging of the ring array suffers from the interference of high-level side lobes. In this work, a hybrid deconvolution method based on modal composition beamforming is used to explore the ability of a multi-arm spiral array to separate different speed sources. Considering the even energy distribution from the out-of-focus source along the circular trajectory, the beamforming result of out-of-focus sources exhibits a weaker amplitude than the source amplitude. Therefore, out-of-focus sources can be considered noise. First, the point spread function is derived based on the modal transfer function. Then, a system of linear equations is constructed based on an incomplete cross-point spread function matrix. Finally, the source separation is solved through sparse-constrained deconvolution. Simulation and experimental results demonstrate that this method can accurately locate and separate different rotational speed sound sources.

Developing a workflow for the isolation of hybridoma cells producing fully human antigen-specific antibodies using a surface IgG detection method

The antigen-mediated B cell isolation method, based on the detection of surface IgG (sIgG), has increased the efficiency of therapeutic antibody (Ab) discovery. However, the reduction in sIgG expression on B cells during plasma cell differentiation presents challenges as it enables Ab production from only a small subset of B cells (e.g., memory B cells). The present study aimed to addressed this problem by developing a workflow to isolate human-IgG-secreting hybridoma cells produced by cell fusion, the majority of which express sIgG. We showed that our sIgG-based antigen-coated bead separation method efficiently enriched hybridoma cells expressing antigen-specific Abs with a yield of 83.5% (from the cell fusion pool) and a positive rate of 73.2%. Furthermore, because the separation could be performed after only a short (1–2-day) culture period following cell fusion, diverse hybridoma clones could be obtained, minimizing clonal selection and the incidence of duplicates. Given that the expression of membrane-bound IgG and sIgG are regulated by different splicing mechanisms, we speculate that the cell fusion step potentially attenuated the suppression of human sIgG expression. Overall, our proposed method is expected to markedly improve the efficiency of therapeutic Ab candidate production, which will have important clinical implications.

Optimization of solvent cooling crystallization process for separating phenanthrene from 9-fluorenone by COSMO-RS and solubility calculation approach

Phenanthrene (Phe) and fluorene (Flu) are crucial chemical intermediates with applications in materials, medicine, and pesticides. However, conventional separation methods struggle to effectively isolate phenanthrene from fluorene due to their similar physical properties. To address this challenge, a reaction–separation coupling technique was employed to convert fluorene into 9-fluorenone (9-Fluo), followed by the separation of phenanthrene from 9-fluorenone using solvent-cooling crystallization. Initially, the relative solubilities of phenanthrene and 9-fluorenone in 2072 solvents were calculated using COSMO-RS for preliminary screening. Among various conventional short-chain aliphatic alcohols and low-carbon saturated hydrocarbons, methanol, and cyclohexane were identified as the most effective solvents based on their solubility selectivity (SS). The molecular interactions between phenanthrene or 9-fluorenone and these solvents were analyzed using theoretical methods such as σ-potential/profile, infinite dilution activity coefficients in COSMO-RS, and Hansen solubility parameters, with further confirmation from FTIR tests. The optimal liquid–solid ratios were determined using both phase diagram measurements and solubility calculations. The reaction conversion of fluorene to 9-fluorenone was complete regardless of the raw material used. Phenanthrene and 9-fluorenone were effectively separated using methanol and cyclohexane with optimum liquid–solid mass ratios of 1.6:1 and 2.8:1, respectively. In the model mixture, the contents of phenanthrene and 9-fluorenone exceeded 98 wt%, with yields above 91 wt%. For anthracene residue, the content of 9-fluorenone reached 93.98 wt% with a yield of 84.52 wt%, while its content was only 76.58 wt% due to the accumulation of other components in phenanthrene.

Apparent effective ionization coefficient in N2 and O2 gas mixtures determined with two separate methods

N2:O2 gas mixtures are important for applications of atmospheric pressure plasmas such as ozone production, air purification from VOCs and NOx and surface treatments. Fundamental parameters such as the effective ionization coefficient are inputs for theoretical plasma models for applications and must thus be accurately known. This work determined the apparent effective ionization coefficient in N2:O2 mixtures in a broad reduced electric field strength E/N range of 150–1200 Td with two separate methods and compared with BOLSIG+ calculations of reduced effective ionization coefficient. Additionally, the equilibrium distance required to establish a steady-state electron energy distribution was estimated from spatial profiles of optical emission.

On the greenness of separation modes containing compressed fluids

BackgroundIn the past three decades, liquid chromatography (LC) has been recognized as a significant environmental, health, and safety burden due to its heavy reliance on toxic organic solvents. Various chromatographic modes are in vogue today for complex analyses, such as sub/supercritical fluid chromatography (SFC) and enhanced fluidity liquid chromatography (EFLC). These modes are often advertised as "universally green" compared to the traditional allliquid reversed (RPLC) and normal phases (NPLC). Quantitative greenness evaluations must be done to validate or invalidate this assumption and allow separation scientists to make educated choices when deciding on what mode to use. ResultsIn this work, we modify the Analytical Method Greenness Score (AMGS) to include the cycle time of the instrument, and with the help of the first-order optimality condition (by setting the AMGS gradient = 0), we show that SFC and EFLC are not always the greenest option as they are often thought to be. Most of the greenness metrics have ignored the cycle time of instruments, yet this key component changes the entire AMGS response to flow rate. The complex case of separating tobacco alkaloid enantiomers (nicotine, nornicotine, anabasine, and anatabine) was selected as an illustrative example for comparing and contrasting separation modes using the modified greenness metric. These enantiomers have been selected due to their notorious difficulty in separation over the past 30 years. Using this family of molecules, four unique retention patterns were observed covering a wide variety of retention phenomena seen in small molecule enantioseparations. SignificanceThe modified AMGS metric will assist practicing analytical chemists in assessing the environmental impact of their separation methods from a single run in a given chromatographic mode. The proposed methodology identifies the minimum AMGS score corresponding to the greenest separation for routine chemical analysis.

A-037 A1c by separation and enzymatic methods: what's the difference?

Abstract Background Accurate values for hemoglobin A1c (HbA1c) are crucial for diagnosing and monitoring diabetes mellitus. Two common methods to measure HbA1c are capillary electrophoresis (CE) and immunoassay (IA). Many methods used to measure HbA1c are prone to interferences from hemoglobin variants and abnormalities affecting the red blood cell’s (RBC) turnover. Consequently, the average estimated glucose levels using the HbA1c value can be unreliable in diabetics with hemoglobinopathies and other RBC lifetime disorders. Separation methods such as CE can capture hemoglobinopathy information, while IA methods may not. We performed this study in a population with relatively high levels of hemoglobin disorders to evaluate the performance of HbA1c testing on the Alinity platform (IA) against the Sebia Capillarys 3 Tera instrument (CE). Methods Samples were identified retrospectively based on a search of the Electronic Medical Record for all patients with an ordered and resulted HbA1c and complete blood count in the Montefiore Medical Center the day prior to sampling. Routine HbA1c testing was performed by an Abbott Immunoassay method on the Abbott Alinity Instrument and CBC results were obtained from a Sysmex XN2100 instrument. Records were compared by patient name, medical record number, and sample collection time to identify all patients with CBC and HbA1c drawn within one hour of each other. Those samples were retrieved from storage (a 4° automated refrigerator) within 48 hours of draw and tested via the Sebia Capillarys 3 Tera instrument using HBA1c kits. Results In this large representative population study (N=2075), there was overall excellent agreement between IA and CE. The correlation coefficient (R2) of the whole dataset was 0.989, with an average bias of 2.7% between the two methods. Additional analysis was performed on those with possible RBC turnover disorder (patients with RBC counts below 4x106/uL or above 6x106/uL, MCVs above 96 fL or below 80 fL, RDW above 17%, or abnormal A2 value: total of 638 samples), those with a hemoglobin variant as detected by the Capillarys 3 instrument (162 samples), or with a measurable hemoglobin F value detected by the Capillarys 3 instrument (37 samples). Samples were sorted into these groups independently and thus there was significant overlap between groups, notably with 23 of 37 samples with elevated HbF also having a hemoglobin variant. In both the RBC disorder and hemoglobinopathies group, similar low bias and high correlations were seen. The elevated F samples showed a clear negative bias (5.6%) for all patients on the IA method as compared with CE. The IA method states that samples with HbF above 5% should not be tested. However, as this is not a separation method, there is no way to test samples for HbF before analysis, and bias was seen for samples below 5%. Conclusions The IA and CE methods showed similar performance across patients regardless of RBC lifetime or hemoglobin disorder status, though presence of HbF is a potential interference and should be considered. Further questions remain for these instruments in terms of correlation with average glucose levels as calculated through CGM instruments.

Rapid Analysis of Sterols in Blood-Derived Samples.

Dysregulations of cholesterol biosynthesis are known to be associated with several pathologies. Due to the rapid growth of clinical investigations in this research area, a specific, fast, and valid method for analyzing cholesterol, its precursors, and metabolites is required. Here, we describe a rapid method for sample preparation, separation, and quantification of sterols in blood-derived samples using polymeric solid phase extraction followed by gas chromatography-mass spectrometry. The validated method demonstrates a reliable quantification of cholesterol, its precursors, and metabolites.

Heat equation for Sturm–Liouville operator with singular propagation and potential

Abstract This article considers the initial boundary value problem for the heat equation with the time-dependent Sturm–Liouville operator with singular potentials. To obtain a solution by the method of separation of variables, the problem is reduced to the problem of eigenvalues of the Sturm–Liouville operator. Further on, the solution to the initial boundary value problem is constructed in the form of a Fourier series expansion. A heterogeneous case is also considered. Finally, we establish the well-posedness of the equation in the case when the potential and initial data are distributions, also for singular time-dependent coefficients.

Free vibrations of a Continuous-discrete multi-span Beam taking into account inertial Rotation Forces

Objective. The aim of the study is to estimate free vibrations of a continuousdiscrete multi-span beam taking into account the inertial forces of rotation. The goal is to determine the spectra of natural frequencies, damping coefficients and natural modes. Method. The study is based on the methods of linear mechanics of structures; numerical and numericalanalytical calculation methods. The solution to the problem is found using the method of separation of variables. Rotational movements of particles of continuous sections are taken into account according to one of the models of the Timoshenko beam. The D'Alembert principle and hypotheses on the smallness of displacements and angles of rotation of sections are used. Result. A system of equations in matrix-vector form is obtained. The mathematical model of transverse vibrations consists of three systems of differential equations. The equation includes transverse forces, external concentrated forces, d'Alembert inertial forcesi, and linear-viscous resistance forces. The inertial forces of rotation of concentrated masses are taken into account. The boundary and other additional conditions to the equations correspond to the calculation scheme. The left end of the beam is hinged. The conjugation conditions are met at the junction of the sections. Conclusions. This random process of disturbances is very close to the processes used in deterministic problems. The amplitudes and standard deviations of displacements in the deterministic and stochastic problems almost coincide, which confirms the reliability of the proposed calculation theory. Analysis of the curves shows that the standard deviations significantly depend on the degree of correlation of the components of the vector random process of disturbances. The use of modern computing computer systems such as Matlab allows us to successfully combine the advantages of both numerical and graphical methods.

Dual-Column Stopped-Flow GC Method for Quantification of Permanent Gases, Water, and Organic Acids from a Single Injection.

Analysis of permanent gases and organic acids is typically performed with separate methods due to challenges in achieving sufficient resolution when using GC columns that are chemically compatible with acids. We developed a method to analyze samples containing high levels of water, organic acids, oxygenates, and permanent gases (CO, CO2, and C2H4) using a single injection. Resolution is achieved using two columns: (1) an HP-FFAP column resistant to water and acids, which separates compounds based on hydrogen-bonding affinity, and (2) a GS-CarbonPLOT column capable of separating permanent gases. We employed a column isolation methodology using rotary valves to allow a heart cut of permanent gases, which coelute off the HP-FFAP column, to be trapped on the CarbonPLOT column. After separation and analysis of water, organic acids, and oxygenates via the HP-FFAP column, flow is resumed on the CarbonPLOT column, and the permanent gases are separated independently. By utilizing the unique combination of columns and the stopped-flow sequence, we achieved separation and quantification of the wide array of compounds occurring during lactic acid dehydration to acrylic acid from a single injection without the need for a sophisticated flow modulator or multiple GCs or detector arrays. This GC apparatus serves as an economical in-line analysis method for our catalytic studies and is applicable to a wide array of samples relevant to biobased fuels and chemicals.

Peptide retention time prediction for electrostatic repulsion-hydrophilic interaction chromatography

Electrostatic Repulsion-Hydrophilic Interaction Chromatography (ERLIC) is one of the legacy separation tools developed by Dr. Andrew Alpert and has been used for developing unique separation methods of hydrophilic compounds, including peptides. In the past it has been studied using designed peptide libraries to elucidate major features of its separation mechanism, while comprehensive peptide retention modeling for ERLIC is still lacking. In this work we employed a proteomics-derived ∼170,000 peptide retention datasets to evaluate major ERLIC retention features using the framework of our Sequence-Specific Retention Calculator model. The separation conditions were adjusted to obtain a wider proteome coverage, particularly for non-modified peptides, resulting in a superior separation orthogonality for a 2D LC combination with reversed-phase C18 LC-MS in the second dimension. The SSRCalc ERLIC model presents a consistent theme with the existing ERLIC retention mechanism, reflecting a dependence on peptide orientation and the position of charged and hydrophilic residues across the peptide backbone. R2 values of 0.935 and 0.955 accuracy were demonstrated for the standard interpretable SSRCalc model and machine learning algorithm, respectively. The effects of various PTMs on peptide retention were evaluated in this study, covering spontaneous (oxidation, deamidation) and enzymatic (N-terminal acetylation, phosphorylation, glycosylation) modifications.

Total separation of multi-plastic wastes using magnetic levitation with adjustable sensitivity

Novel separation method with high efficiency is of great significance for mechanical recycling mixed waste plastics plays. However, the efficiency of most extant methods is restricted by their shortage that the methods can only deal with binary mixtures. In this paper, a novel magnetic levitation (MagLev) separation method based on scaled-up MagLev device is proposed to handle multi-plastics. A theoretical model on distribution of magnetic flux intensity and levitation conditions is established to guide the design of separation process. Based on the theoretical analysis, different processes for separation of multi-plastics with different purpose can be realized. The high sensitivity allows the separation of plastics with similar appearances (e.g. transparent plastics like polycarbonate and polymethyl methacrylate) and densities (difference with 0.01 g/cm3). The adjustable distribution of magnetic field changes the levitation condition of the waste plastics. Thus, the sequential separation of multi-plastics and extraction of target material from multi-plastics mixture are successfully addressed. The experiments demonstrate that the purities of separated multiple plastics reach to approx. 100 %. Furthermore, additional advantages of low cost and no energy consumed in separation process make the method a promising solution for economically-viable and environmentally-friendly mass production procedure.

Formation of bovine serum albumin-galangin nanoparticles and their potential to inhibit ROS-induced inflammation: Enthanol desolvation vs. pH-shiftng method

pH-shifting method, as an eco-friendly approach, is a promising alternative to desolvation method, yet systematic comparison of their property is still lacking. In this study, bovine serum albumin-galangin nanoparticles (BSA-GA NPs) were designed for alleviating ROS-mediated macrophage inflammation by the 2 separate methods. Compared with the desolvation method, BSA exhibited a higher loading capacity for GA under the pH-shifting method, which was attributed to the exposure of the binding site leading to enhanced affinity for GA and a more compact particle structure. Further analyses evidenced that the electron arrangement and crystal structure of GA changed with different methods. The content of random coil of BSA was elevated after pH-shifting method. Besides, the smaller size rendered the pH-shifting treated BSA-GA NPs easier to be taken up by macrophages, while the enhanced specific surface area conferred excellent ROS scavenging and anti-inflammatory performances. This study may provide new insights into the choice of loading methods.

Applying membrane techniques to separate hydrogen from natural gas for hydrogen technologies

Today, the world's energy industry is grappling with several issues arising from restrictions on harmful greenhouse gas emissions, related to climate and environmental protection. Methods of storing energy in various types of carriers are becoming increasingly important, the most promising of which is hydrogen. Various methods of storing it are being considered, where an interesting option is to store it temporarily, under certain conditions, in existing natural gas networks. The challenge, however, is its subsequent recovery. Membrane technology is receiving special attention among recovery methods because of its potential efficiency in hydrogen separation, safety and ease of operation, low energy requirements and environmental friendliness. The paper presents a literature study of the issue, preliminary analyses of membrane gas separation and the advisability of the direction of the new research that has been undertaken. The possibility of applying membrane techniques to the process of separating hydrogen from natural gas in transmission and distribution networks for hydrogen storage technology is presented. Preliminary research is geared toward exploring the scope of applicability of this method of membrane separation, in which the primary goal is to determine the possibility of separating hydrogen from methane. In this paper, within the framework of the adopted simplified structure of the polymeric membrane module, the basic parameters of the process (share of hydrogen in the feed, membrane surface area) were determined, as well as the influence and dependence of transmembrane pressure (permeate) on the values of membrane selectivity, recovery rate and purity of the obtained hydrogen.