Kinetic control concept for the diffusion processes of paracetamol active molecules across affinity polymer membranes from acidic solutions

Background Paracetamol compound remains the most used pharmaceutical as an analgesic and antipyretic for pain and fever, often identified in aquatic environments. The elimination of this compound from wastewater is one of the critical operations carried out by advanced industries. Our work objective was to assess studies based on membrane processes by using two membranes, polymer inclusion membrane and grafted polymer membrane containing gluconic acid as an extractive agent for extracting and recovering paracetamol compound from aqueous solutions. Result The elaborated membrane characterizations were assessed using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Kinetic and thermodynamic models have been applied to determine the values of macroscopic (P and J0), microscopic (D* and Kass), activation and thermodynamic parameters (Ea, ΔH#, ΔS#, ΔH#diss, and ΔH#th). All results showed that the PVA–GA was more performant than its counterpart GPM–GA, with apparent diffusion coefficient values (107D*) of 41.807 and 31.211 cm2 s−1 respectively, at T = 308 K. In addition, the extraction process for these membranes was more efficient at pH = 1. The relatively low values of activation energy (Ea), activation association enthalpy (ΔH≠ass), and activation dissociation enthalpy (ΔH≠diss) have indicated a kinetic control for the oriented processes studied across the adopted membranes much more than the energetic counterpart. Conclusion The results presented for the quantification of oriented membrane process ensured clean, sustainable, and environmentally friendly methods for the extraction and recovery of paracetamol molecule as a high-value substance.

Kinetic Control Concept for the Diffusion Processes of Paracetamol Active Molecules Across Affinity Polymer Membranes

Background: Paracetamol compound remains the most used pharmaceutical as an analgesic and antipyretic for pain and fever. It has been detected in aquatic environments. The recovery of this compound from wastewater is one of the important operations carried out by modern industries. Its recovery is especially important for environmental protection. Currently, research is focused on membrane technology that has gained considerable interest over the last decades due to the various advantages that it presents.Result: Our work reports the selective extraction of paracetamol from liquid solution using two types of affinity polymer membranes: (i) polymer inclusion membrane (PIM) and (ii) grafted polymer membrane (GPM). The same extractive agent, gluconic acid (GA), is used for both. After total characterization, the developed membranes were adopted. Kinetic and thermodynamic models have been used to determine the values of various macroscopic parameters, permeability (P), and initial flux (J0), to understand the membrane performance. The same techniques have been used to determine the values of different microscopic parameters, association constant (Kass), and apparent diffusion coefficient (D*) that determine the interaction between the paracetamol substrates and the extractive agent, necessary for the diffusion of paracetamol molecules through the membrane. Similarly, the effects of initial concentration (C0), acidity (pH), and temperature were examined.Conclusion: The experimental results allow the determination of values of activation and thermodynamic parameters (Ea, ΔH#, ΔS#, ΔH#dis, and ΔH#th). The results explain the membrane performances and confirm that the energetic or kinetic aspects control the mechanisms related to the oriented processes. The results also indicate that it is possible to recycle wastewater and eliminate contaminants such as paracetamol.

Comparison of extractive distillation flowsheets for methanol–tetrahydrofuran–water mixtures

Objectives. Synthesis and comparative analysis of the extractive distillation flowsheets for aqueous mixtures of solvents utilized in pharmaceutical industries using the example of a methanol−tetrahydrofuran−water system with various compositions. The ternary system contains two minimally boiling azeotropes that exist in a vapor–liquid phase equilibrium. To evaluate the selective effect of glycerol, the phase equilibria of the methanol–tetrahydrofuran–water and methanol–tetrahydrofuran–water–glycerol systems at 101.32 kPa were studied.Methods. The calculations were carried out in the Aspen Plus V.9.0 software package. The vapor–liquid equilibria were simulated using the non-random two-liquid (NRTL) equation with the binary interaction parameters of the software package database. To account for the non-ideal behavior of the vapor phase, the Redlich–Kwong equation of state was used. The calculations of the extractive distillation schemes were carried out at 101.32 kPa.Results. The conceptual flowsheets of extractive distillation are proposed. The flowsheets consist of three (schemes I–III) or four (scheme IV) distillation columns operating at atmospheric pressure. In schemes I and II, the extractive distillation of the mixtures is carried out with tetrahydrofuran isolation occurring in the distillate stream. Further separation in the schemes differs in the order of glycerol isolation: in the third column for scheme I (traditional extractive distillation complex) or in the second column for scheme II (two-column extractive distillation complex + methanol/water separation column). Sсheme III caters to the complete dehydration of the basic ternary mixtures, followed by the extractive distillation of the azeotropic methanol–tetrahydrofuran system, also with glycerol. Sсheme IV includes a preconcentration column (for the partial removal of water) and a traditional extractive distillation complex.Conclusions. According to the criterion of least energy consumption for separation (the total load of the reboilers of distillation columns), sсheme I (a traditional complex of extractive distillation) is recommended. Additionally, the energy expended for the separation of the basic equimolar mixture using glycerol as the extractive agent was compared with that expended using another selective agent: 1,2-ethanediol. Glycerol is an effective extractive agent because it reduces energy consumption, in comparison with 1,2-ethanediol, by more than 5%.

Simulasi CHEMCAD: Studi Kasus Distilasi Ekstraktif pada Campuran Terner n-Propil Asetat/n-Propanol/Air

Pemisahan n-propil asetat dari campuran terner n-propil asetat/n-propanol/air merupakan salah satu proses yang tidak dapat dilakukan dengan distilasi sederhana. Adanya azeotrop terner minimum dari campuran tersebut menyebabkan n-propil asetat hanya dapat dipisahkan dari campuran n-propanol dan air salah satunya dengan metode distilasi ekstraktif. Distilasi ekstraktif merupakan proses vaporisasi parsial dengan menambahkan suatu agen pemisah non-volatil yang disebut sebagai sovent atau agen ekstraktif. Solvent yang digunakan dalam simulasi proses ini adalah campuran DMSO (Dimetil Sulfoksida) dan Gliserol dengan komposisi 50 % massa dengan perbandingan 1:2 untuk massa umpan kolom : solvent. Feed yang digunakan adalah n-propanol (10 kmol/jam) dan asam asetat (13 kmol/jam) masing-masing pada suhu 25°C dan tekanan 101,3 kPa. Hasil n-propil asetat terbaik diperoleh saat solvent diumpankan pada stage 5 dengan fraksi mol n-propil asetat pada distilat 0,9975 disertai dengan minimumnya energi reboiler yang digunakan pada konfigurasi kolom ini.n-Propyl acetate separation of the n-propyl acetate /n-propanol/water mixture composition can't be done by simple distillation. The existence of minimum ternary azeotrope on the mixture causes n-propyl acetate can be separated only by extractive distillation method. Extractive distillation is a partial vaporization process in the presence of a non-volatile separating agent called as solvent or extractive agent. Solvent used in the simulation process is DMSO (Dimethyl Sulfoxide)-Glycerol mixture (50% mass) with a ratio of 1: 2 for column feed : solvent. n-Propanol (10 kmol/hour) and acetic acid (13 kmol/hour) are fed into reactor (before extractive distillation process) at 25°C and 101.3 kPa, respectively. The best results of n-propyl acetate were obtained when the solvent was fed to stage 5 in which mole fraction of n-propyl acetate in distillate 0.9975 accompanied by the minimum reboiler energy used in this column configuration.

RESEARCH OF VARIOUS ISO-MANIFOLDS IN FOUR COMPONENT SYSTEMS CONTAINING BIAZEOTROPIC BINARY CONSTITUENTS

In the present work, an analysis of the mutual arrangement of a number of iso-manifolds in the concentration tetrahedron formed by the components of the separated mixture and an additional substance, an extractive agent, was carried out to estimate the possibility of separating three-component mixtures containing biazeotropic constituents by extractive rectification. The objects of research were four-component systems formed by ternary constituents (butyl propionate (BP) - propionic acid (PA) - butyl butyrate (BB), butyl propionate - propionic acid - butyric acid (BA), butyl butyrate - butyric acid -butyl propionate, butyl butyrate - butyric acid -propionic acid) of the commercially important BP-PA-BB-BA system, and the extractive agent sulfolane. Using the results of the computational experiment based on mathematical model NRTL-HOC we obtained complete data on the vapor-liquid equilibrium in binary, three- and four-component systems. The structures of liquid-vapor phase diagrams were obtained, and thermodynamic-topological analysis of all four-component systems was carried out. The mutual arrangement in the concentration tetrahedron of manifolds of relative volatility (equal to 1) of the components, reflecting the evolution of pseudo-azeotropes in sections with a constant concentration of the extractive agent; pseudo-ideal manifolds along which the activity coefficients of the components of the base (separated) mixture are equal to each other; isothermo-isobaric manifolds generated by Bancroft points in binary azeotropic constituents were determined. We established that it is possible to separate the studied three-component mixtures by extractive rectification using sulfolane.

Process of Facilitated Extraction of Vanadium Ions through Supported Liquid Membranes: Parameters and Mechanism

To conduct experiments related to the facilitated extraction phenomenon of vanadium ions (VO2+), three supported liquid membranes (SLMs) were prepared, each containing 0.01 M of methyl cholate (MC), resorcinarene (RESO), or trioctylamine (TOA) as extractive agents. Kinetic and thermodynamic models were developed, based on the interaction of the substrate (VO2+) with the extractive agent T and the diffusion of the formed entity (TS) through the membrane. The experimental results verify the models, and to determine, macroscopic parameters, permeabilities (P) and initial fluxes (J0), and microscopic parameters, association constants (Kass) and apparent diffusion coefficients (D⁎) related to formed entities (TS) and their diffusion through the membrane organic phase. The experimental results indicate that the mechanism on the migration of the VO2+ ions through the membrane organic phase is based on the successive jumps of substrate, from one site to another of the extractive agent. To explain these results and understand the mechanism, we studied influence of temperature factor, and we determined activation parameters (Ea, ΔH≠, and ΔS≠). The results show that this extraction phenomenon is governed by a structural term. Therefore, the membrane performance changes according to nature and structure of the association site presented by each of extractive agents.

Separation processes for high purity ethanol production

Globally there is renewed interest in the production of alternate fuels in the form of bioethanol and biodiesel. This is mainly due to the realization that crude oil stocks are limited hence the swing towards more renewable sources of energy. Bioethanol and biodiesel have received increasing attention as excellent alternative fuels and have virtually limitless potential for growth. One of the key processing challenges in the manufacturing of biofuels is the production of high purity products. As bioethanol is the part of biofuels, the main challenge facing bioethanol production is the separation of high purity ethanol. The separation of ethanol from water is difficult because of the existence of an azeotrope in the mixture. However, the separation of the ethanol/water azeotropic system could be achieved by the addition of a suitable solvent, which influences the activity coefficient, relative volatility, flux and the separation factor or by physical separation based on molecular size. In this study, two methods of high purity ethanol separation are investigated: extractive distillation and pervaporation. The objective of this project was to optimize and compare the performance of pervaporation and extraction distillation in order to produce high purity ethanol. The scopes of the investigation include:  Study of effect of various parameters (i) operating pressure, (ii) operating temperature, and (iii) feed composition on the separation of ethanol-water system using pervaporation.  Study the effect of using salt as a separating agent and the operating pressure in the extractive distillation process. The pervaporation unit using a composite flat sheet membrane (hydrophilic membrane) produced a high purity ethanol, and also achieved an increase in water flux with increasing pressure and feed temperature. The pervaporation unit facilitated separation beyond the ethanol – water system azeotropic point. It is concluded that varying the feed temperature and the operating pressure, the performance of the pervaporation membrane can be optimised. v The extractive distillation study using salt as an extractive agent was performed using the low pressure vapour-liquid equilibrium (LPVLE) still, which was developed by (Raal and Mühlbauer, 1998) and later modified by (Joseph et al. 2001). The VLE study indicated an increase in relative volatility with increase in salt concentration and increase in pressure operating pressure. Salt concentration at 0.2 g/ml and 0.3 g/ml showed complete elimination of the azeotrope in ethanol-water system. The experimental VLE data were regressed using the combined method and Gibbs excess energy models, particular Wilson and NRTL. Both models have shown the best fit for the ethanol/water system with average absolute deviation (AAD) below 0.005. The VLE data were subjected to consistency test and according to the Point test, were of high consistency with average absolute deviations between experimental and calculated vapour composition below 0.005. Both extractive distillation using salt as an extractive agent and pervaporation are potential technologies that could be utilized for the production of high purity ethanol in boiethanol-production.