Separation technique on proteins via a pH-Parametric pump : a theoretical and experimental study

The separation of protein mixtures via pH-parametric pumping was investigated both theoretically and experimentally. A simple system consisting of one column packed either with cation or anion exchanger was first considered. A system of parapumps was then developed with more columns which were connected in series and packed alternately with cation and anion exchangers. Various methods of operation of parapumps are discussed. Enrichment and spliting of protein mixtures were examined. In most cases, the separation factor was defined at a steady state condition and was improved by increasing the number of cycles and columns. Computational methods for predicting both Batch and Semi-Continuous parametric pump performance, with equilibrium conditions described were developed. The physical system was characterized by means of interphase mass transfer rates. These methods were based on a set of exterior and interior material balances. Linear parameters were calculated for the adsorption of the solute on the ion exchanger. A mathematical model based on elementary matrix algebra was developed as well as a graphical method. The properties of eigenvalues and eigenvectors of this formalism were studied. The subject was extended to more complex situations involving a multi-column, and the separation of multi-protein. There is good agreement between predicted and experimental results

Extraction of Lead Ions and Partitioning Behaviour in Aqueous Biphasic Systems Based on Polyethylene Glycol and Different Salts

Lead ions are environmental pollutants often present in very low concentrations, which makes them difficult to detect and, thus, present problems for environmental monitoring. In this study, we examined the performance of aqueous biphasic systems based on polyethylene glycol (PEG, molecular mass of 4000 g mol–1) with ammonium sulfate (NH4)2SO4, magnesium sulfate (MgSO4), sodium sulfate (Na2SO4), and trisodium citrate (Na3C6H5O7) for the separation of lead(II) ions from aqueous solutions. We investigated the effects of salt types and the ratio of PEG4000 to salt on the extraction efficiency of lead(II) removal at constant temperatures of 303 K and 0.1 MPa. Additionally, we determined the cloud points (solubility equilibrium curve) and tie-lines for four ternary systems comprising PEG4000, water, and salt (either (NH4)2SO4, MgSO4, Na2SO4, or Na3C6H5O7) under the same conditions. A maximum lead(II) extraction efficiency of 74.4% was achieved using the PEG4000/(NH4)2SO4 system with a mass fraction ratio of PEG4000 to (NH4)2SO4 of 0.2:0.12. This outcome highlights the significant potential of utilizing aqueous biphasic systems based on PEG4000 to separate lead(II) from aqueous solutions efficiently

Synergistic effect of Thiourea and HCl on Palladium (II) recovery: An investigation on Chemical structures and thermodynamic stability via DFT

This work duly investigates the recovery of Pd (II) chlorocomplexes from industrial wastewater. Chemical structures and thermodynamic stabilities of the complex formed are evaluated via density functional theory (DFT). By applying synergistic solutions of thiourea mixed with hydrochloric acid (HCl), the stripping reaction of Pd (II) in the loaded Aliquat 336 occurs and Pd (II) chlorocomplexes coordinated thiourea ligands are formed, thus 80.19% of Pd (II) chlorocomplexes can be recovered. The aim of this study is to gain a better understanding of the stripping mechanisms and the structure of the complexes formed via the synergistic system. Such an understanding is still limited since little research has been conducted in this field. Owing to their molecular geometry, ligand coordination and donor groups play a vital role in the reactivity of palladium (II) complex. Quantum models have been developed to evaluate the chemical structure and thermodynamics stability of ((NH2)2CS·PdCl2) namely: (i) DFT with B3LYP/6-31g(d,p) and MP2/6-31g(d,p) basis set, (ii) MP2 with cc-pVTZ basis set and (iii) CCSD(T)/cc-pVTZ. Results demonstrate that the highest geometric stability exhibited is the structure of Pd-S bonding with 180° Cl-Pd-Cl. The distance (r) and angle (a) of the selected geometrical parameters for (NH2)2CS·PdCl2 complex are reported. Additionally, FTIR and UV–vis spectroscopies have been conducted to analyze the sampling solutions. Further, the calculated vibrational frequencies and experimental spectroscopic results show good agreement with the optimized geometry

The elimination of arsenic from natural gas condensate via pulse sieve-plate column: Experimental and application of DFT for chemical structure

This work focuses on the elimination of arsenic ions from natural gas condensate via pulse sieve-plate column. The extraction of arsenic ions using the extractants: hydrochloric acid (HCl), Methanol (MeOH) and HCl/MeOH are investigated via density functional theory (DFT). The DFT method clearly demonstrates the synergistic reaction mechanism of the extractant HCl/MeOH, providing an improved extraction effect greater than the use of single extractants. Applying optimal conditions: MeOH (5 M), HCl (1 M), feed flowrate (55 ml/min), extractant flowrate (220 ml/min) and pulse velocity (2 cm/s), it is found that the pulse sieve-plate column leads to an increase in extraction of triphenylarsine. Mass-transfer parameters, including the Sauter mean diameter: 1.917 mm, the axial dispersion coefficient of the continuous phase: 0.012 m2/s, the extract percentage: 94.55%, the overall mass transfer coefficient: 1.228x10-3 s−1 as well as height of a transfer unit (HTU): 22.92 cm are also calculated under optimal conditions

The simultaneous elimination of arsenic and mercury ions via hollow fiber supported liquid membrane and their reaction mechanisms: Experimental and modeling based on DFT and generating function

This study investigates the simultaneous removal of low concentrations of arsenic and mercury ions from synthetic produced water via hollow fiber supported liquid membrane (HFSLM). Results show that HFSLM can remove both arsenic and mercury ions from synthetic produced water to less than 0.02 and 0.001 mg·L-1, respectively. These final concentrations comply with the wastewater standard of Thailand. Percentages of extraction for arsenic and mercury ions proved to be about 100 %. Those of recovery for arsenic and mercury ions reached 70 % and 75 %, respectively. A quantum model based on density functional theory (DFT) is introduced to analyze the forming and breaking of supramolecular complex species in the processes of extraction and recovery, respectively. Furthermore, the concept of Generating Function is applied to construct a mathematical model for forecasting the potential of removing metal ions via HFSLM. The mathematical model conforms to the experimental data, having an average relative deviation of 5 %. The results of this study provide a better understanding of the transport mechanisms of arsenic and mercury ions

Application of solubility data on a hollow fiber supported liquid membrane system for the extraction of gold (I) cyanide from electronic industrial wastewater

The solubility ternary system was used to develop a hollow fiber-supported liquid membrane process for the extraction of gold (I) cyanide from electronics industry wastewater. Five kinds of diluents (p-xylene, cyclohexene, 1-dodecanol, n-heptane, and n-dodecane) were applied to the solubility of ternary systems (Aliquat336þwaterþdiluents) at 303.2 K and atmospheric pressure. 1-dodecanol, p-xylene, and cyclohexane were selected because they are completely soluble in Aliquat336 in any composition. The effects of pH on the feed solution and type of diluent were examined. The highest extraction and stripping percentages of 99.9 and 61.4, respectively, were achieved at a feed solution pH of 10.0 using pxylene as the best diluent

Synergistic effect of arsenic removal from petroleum condensate via liquid-liquid extraction: Thermodynamics, kinetics, DFT and McCabe-Thiele method

This work presents the purification of petroleum condensate by removing arsenic ions via liquid-liquid extraction (LLE). Influence of pure and synergistic extractants is investigated. In terms of the practicability, following parameters are examined: the type of extractant, operating time, and temperature. Response surface methodology is used to design parameters such as organic-aqueous ratio and extractant concentration. Under optimal conditions; a mixture of 1 mol/L HCl and 0.02 mol/L thiourea with an organic/aqueous ratio of 1:4 at 323.15 K for 60 min, the extraction of arsenic reached 78.2 %. Further, batch simulation via two-stage counter-current extraction, and estimation by McCabe-Thiele diagram proved to be enhanced arsenic extraction to 95.3 %. Analysis by FTIR show that arsenic ions in petroleum condensate are formed as triphenylarsine compound ((C6H5)3As). The process of arsenic removal proved to be zero-order endothermic, irreversible and spontaneous reaction. The results obtained from the density functional theory (DFT) confirm that arsenic ions react with the synergistic extractant: effectively forming a covalent bond (As–S)

Extraction of Lead Ions and Partitioning Behaviour in Aqueous Biphasic Systems Based on Polyethylene Glycol and Different Salts

Lead ions are environmental pollutants often present in very low concentrations, which makes them difficult to detect and, thus, present problems for environmental monitoring. In this study, we examined the performance of aqueous biphasic systems based on polyethylene glycol (PEG, molecular mass of 4000 g mol1) with ammonium sulphate (NH4)2SO4, magnesium sulphate (MgSO4), sodium sulphate (Na2SO4) and trisodium citrate (Na3C6H5O7) for the separation of lead (II) ions from aqueous solutions. We investigated the effects of salt types and the ratio of PEG4000 to salt on the extraction efficiency of lead (II) removal at constant temperatures of 303 K and 0.1 MPa. Additionally, we determined the cloud points (solubility equilibrium curve) and tie-lines for four ternary systems comprising PEG4000, water, and salt (either (NH4)2SO4, MgSO4, Na2SO4, or Na3C6H5O7) under the same conditions. A maximum lead (II) extraction efficiency of 74.4% was achieved using the PEG4000/(NH4)2SO4 system with a mass fraction ratio of PEG4000 to (NH4)2SO4 of 0.2:0.12. This outcome highlights the significant potential of utilizing aqueous biphasic systems based on PEG4000 to separate lead (II) from aqueous solutions efficiently