Separation Factor Research Articles

Enhancing ammonia selectivity in membrane distillation: The role of membrane structural characteristics

Ammonia is emerging as a promising carbon-free fuel in the pursuit of carbon neutrality due to its combustion process, which produces no carbon dioxide emissions. Membrane distillation (MD) for recovering ammonia from wastewater is an alternative to conventional energy-intensive production methods. However, the efficiency of MD processes is hindered by the low purity of the recovered ammonia stream, primarily due to excessive water permeation. In this study, we investigated the influence of membrane properties on water and ammonia permeation using poly(vinylidene fluoride-co-hexafluoropropene) (PVDF-HFP) nanofibrous membranes fabricated in-house via electrospinning. Additionally, we compared the impact of manipulating membrane characteristics with adjusting operating conditions, employing a commercial PVDF membrane as the conventional approach for controlling ammonia purity. Our findings revealed that increasing membrane thickness (from 82 to 283 μm) under isothermal conditions substantially enhanced the ammonia separation factor (from 4.07 to 7.28) by approximately 80 %, whereas reducing the feed temperature from 50 °C to 43 °C yielded only a 20 % improvement. Mechanistic modeling of MD for the water-ammonia system illustrated the critical role of membrane thickness in improving ammonia selectivity by markedly reducing water flux while maintaining relatively consistent ammonia flux. The combination of experimental and simulation outcomes suggests that modifying membrane properties or selecting membranes with specific characteristics can enhance ammonia selectivity without significant alterations to operating conditions or configuration.

Plasma centrifugation method for separation of the nuclear waste

The high-throughput, plasma-based, mass separation techniques of nuclear waste are still an active research topic due to the theoretical and practical complexity of processing such waste. The nuclear waste can be separated according to its masses by plasma centrifugation technique. Because of this, the present research has been performed by setting up E → × B → rotation in cold cylindrical plasma surrounded by an ideally conducting homogenous shell inside a plasma centrifuge device. The results obtained are useful in analyzing the magneto-rotational instability (MRI) and trajectories of the plasma particles which are beneficial for improving the throughput and separation factor of the device.

Fluorinated MIL-53(Al) with breathing effect incorporated mixed matrix membranes for enhanced butanol/water pervaporation performance

Fillers of mixed matrix membranes (MMMs) play a crucial role in the pervaporation (PV) separation process. MIL-53(Al) is widely used in the preparation of MMMs due to its high stability, variable pore size, and ease of modification. In this study, fluorinated MIL-53(Al) (4F-MIL-53) was successfully synthesized using a solvent-free method. The introduction of fluorinated group made 4F-MIL-53 have better affinity for butanol and stronger hydrophobicity than MIL-53. Meanwhile, by utilizing its breathing effect, 4F-MIL-53 with narrow pore (4F-MIL-53(np)) could be transformed to 4F-MIL-53 with large pore (4F-MIL-53(lp)) through heat treatment. Also, the flexible framework of 4F-MIL-53 had good affinity with polymer chains. Then, 4F-MIL-53(lp) was introduced into PEBA to prepare MMMs for separating n-butanol/water. Compared with pristine PEBA membrane, the permeation flux and separation factor of the 4F-MIL-53(lp)-20/PEBA MMMs increased by 100.5 % and 90.4 %, respectively. Theoretical calculations indicated that there were multiple intermolecular forces between 4F-MIL-53(lp) and n-butanol, which enhanced the mixed matrix membrane affinity for n-butanol. The calculated self-diffusion coefficient of water in 4F-MIL-53 (lp) was lower than that in MIL-53, indicating that the introduction of fluorinated groups enhanced the hydrophobicity of MMMs. The proposed selection and modification strategies of MOF fillers provide excellent guidance for getting MMMs with high performance.

Hierarchical and defect-free metal-organic framework membranes deep-rooted within flexible nanofiber substrate

Defect-free MOFs membrane on flexible substrate is challenging and promising for industrial applications. In this work, electrospun nanofiber substrates were employed to construct deep-rooted and defect-free ZIF-8 membranes by a symbiotic layer composed of interpenetrated nanofibers and ZIF-8. Nanofibers provide sufficient nucleation sites to construct an interpenetrated “symbiotic layer”, which further supports ZIF-8 growing to be defect-free. Importantly, benefiting from this symbiotic layer, the rigidity difference between substrate and ZIF-8 is well balanced, resulting in ZIF-8 membrane deep-rooted within the support. Furthermore, tannic acid (TA), was combined to modulate the surface chemistry and inter-crystalline defects of ZIF-8 membranes. Finally, a hierarchical ZIF-8 membrane with nanofibers as flexible substrates were obtained. The prepared PAN/TA2-NZIF-80.25 membrane exhibits H2 permeance of 2408 GPU and H2/CO2 selectivity of 21.80. Specifically, compared with the reported MOFs membrane for H2 separation, the H2 permeance of this work locates in a very high region, while proper H2/CO2 separation factor is still remained, exceeding the 2008 upper bound of H2/CO2 separation. Importantly, this membrane presents stable microstructures and separation performance after twisting. The proposed deep-rooted and defect-free ZIF-8 membrane on flexible substrate is competitive to achieve industrial application.

A novel imprinted porous liquid for lithium extraction

AbstractPorous liquids (PLs) are a novel material that combines the advantages of porous solids and liquid fluidity. In this study, we propose an imprinted porous liquid (IPL) with imprinted polymers as the porous framework and a mixture of TOP + FeCl3 as sterically hindered solvents. Quantum chemical computations and characterization results demonstrate the presence of unoccupied pore structure in IPLs. The prepared IPLs exhibit excellent selective adsorption and extraction performance for lithium extraction, achieving a Li/Mg separation factor of 1540 and a single‐stage Li+ extraction efficiency of 86%. The Li+ extraction efficiency remains above 84% even after eight cycles. Analytical characterization along with quantum chemical computations elucidates the mechanism underlying the coupling between extraction and adsorption in IPLs, enabling efficient lithium extraction. By combining imprinting technology with PLs, IPLs expand upon existing frameworks for PLs materials while providing new insights for designing functional solvents.

N-oxide connected zwitterionic polyamide nanofiltration membrane for efficient antibiotic/salt separation

Nanofiltration membrane technology for antibiotic desalination in fermentation broth represents a low-energy and high-purity approach. However, it is constrained by the low perm-selectivity and susceptibility to membrane fouling. Here, we develop a novel zwitterionic nanofiltration membrane by incorporating an N-Oxide directly connected zwitterion N,N-bis(3-aminopropyl)methylamine N-oxide (DNMAO) into the nascent polyamide layer via interfacial polymerization. The N-Oxide derived zwitterion created a looser crosslinking network in addition to the trimesoyl chloride-piperazine (TMC-PIP) network, which was supported by Stokes radius related with molecular weight cut-off measurement, and Brunauer-Emmett-Teller Ar adsorption isotherms. Moreover, the directly connected groups (N+-O-) without spacers endow excellent hydration ability and mitigate membrane fouling. The optimized membrane exhibits a water flux of 114.9 L m−2 h−1 and exceptional anti-fouling performance with a flux recovery ratio as high as about 96.4 %. Furthermore, the salt/antibiotic separation factor maintained at 41.1 when continuously filtrating NaCl/erythromycin (ERY) mixed solution for 7 h, which showed a great potential in antibiotic purification.

A Route to Selective Arsenate Adsorption in Phosphate Solutions via Ternary Metal Biopolymer Composites

With the increased need for improved adsorbents for efficient water treatment, sodium alginate (NaAlg) and chitosan (Chi) represent promising platform biopolymers for the preparation of biocomposite adsorbents for the effective removal of waterborne oxyanion (arsenate (Asi) and orthophosphate (Pi)) contaminants. The TMCs were characterized by spectroscopy (infrared (IR), SEM with an energy dispersive X-ray (SEM-EDX)), point-of-zero-charge (PZC) measurements, and dye adsorption by employing p-nitrophenol at variable pH. Based on dye adsorption results, the adsorbent surface area (SA) was 271 m2/g for Al-TMC, 286 m2/g for Fe-TMC, and 311 m2/g for Cu-TMC. This indicates the role of adsorbent pore structure and swelling in water. Further, the role of either aluminum (Al), copper (Cu), or iron (Fe) for the preparation of TMCs for the selective Asi removal in the presence of Pi as a competitor anion was evaluated. While Al, Fe, and Cu coordinate to the biopolymer framework at C=O sites, only Fe coordinates to –NH2 sites. While Al coordinated via Al-O and interfacial hydroxy groups, Cu showed the formation of Cu2(OH)3NO3 in contrast to Fe, which observed FeOOH formation. Adsorption of Asi was highest for Al-TMC (80 mg/g), followed by Fe-TMC (77 mg/g) and Cu-TMC (31 mg/g). Adsorption of Pi was highest for Al-TMC (93 mg/g), followed by Fe-TMC (66 mg/g) and Cu-TMC (17 mg/g). While Al-TMC showed the highest adsorption capacity overall, only Fe-TMC (followed by Cu-TMC) showed strong arsenate selectivity over orthophosphate. The selectivity toward Asi in presence of Pi was determined and the binary separation factor (αt/c) and the selectivity coefficient (βt) were calculated, where Cu-TMC (αt/c = 6.1; βt = 4.4) and Fe-TMC (αt/c = 8.3; βt = 5.0) exceeded Al-TMC (αt/c = 1.5; βt = 1.2). This work contributes to the field of oxyanion-selective adsorbents via judicious selection of the metal salt precursor during the synthetic design of the ternary biocomposite systems, as demonstrated herein.

Development and Application of HPLC and UFLC Methods for the Analysis of Cardiovascular Drugs

Separation and identification of amiloride, metoprolol, hydrochlorothiazide, Carvedilol and amlodipine, in human plasma using the presented SPE and HPLC procedures was selective, efficient, robust, economical, environmentally friendly, and repeatable. Because plasma samples showed no evidence of a secondary peak, it was determined that the claimed drug-drug interaction between cardiovascular medications did not occur. Furthermore, no new peak was generated, indicating no metabolic product. This is the first report on isolating and identifying these nine cardiovascular medicines. Thus, SPE and HPLC techniques may be used to investigate these 5 cardiovascular medications. Successful monitoring of these medications in human plasma was achieved using the established SPE and HPLC technologies. The results of this inquiry were contrasted with those that had already been released. In comparison to other works in the literature, it was determined that the current study had the best complete baseline separation and lowest detection limit. The retention, separation, and resolution factors were discovered to have ranges of 0.07-9.14, 1.44-4.21, and 2.15-18.66, respectively. The SPE and UFLC techniques created and verified for this purpose were used to examine human plasma samples for the presence of cardiovascular drugs. Peak retention, separation, resolution, and symmetry all matched the reference samples' values. The results for symmetry, separation, and resolution were all in agreement with the reference samples. The methods used to separate and identify amiloride, metoprolol, hydrochlorothiazide; Carvedilol and Amlodipine in human plasma were found to be selective, effective, hardy, affordable, environmentally friendly, and reproducible, according to the authors. The selectivity of the SPE technique was validated by the absence of any secondary signal in the plasma samples. Additionally, there was no evidence of these drugs degrading in the plasma sample. This is the initial report on the simultaneous isolation and identification of these eight medications. The well-known SPE and UFLC techniques were successfully used to monitor these drugs in human plasma. Therefore, these drugs can be detected in any plasma sample using SPE or UFLC methods

Development and Application of HPLC and UFLC Methods for the Analysis of Anti Histaminic Drugs

Research focused on medications used to treat allergic reactions. The results of this inquiry were contrasted with those that had already been released. In comparison to other works in the literature, it was determined that the current study had the best complete baseline separation and lowest detection limit. The retention, separation, and resolution factors were discovered to have ranges of 0.07-9.14, 1.44-4.21, and 2.15-18.66, respectively. The SPE and UFLC techniques created and verified for this purpose were used to examine human plasma samples for the presence of antihistaminic drugs. Peak retention, separation, resolution, and symmetry all matched the reference samples' values. The results for symmetry, separation, and resolution were all in agreement with the reference samples. The methods used to separate and identify Phenylephrine, cetirizine, loratadine, montelukast, and Ebastine in human plasma were found to be selective, effective, hardy, affordable, environmentally friendly, and reproducible, according to the authors. The selectivity of the SPE technique was validated by the absence of any secondary signal in the plasma samples. Additionally, there was no evidence of these drugs degrading in the plasma sample. This is the initial report on the simultaneous isolation and identification of these eight medications. The well-known SPE and UFLC techniques were successfully used to monitor these drugs in human plasma. Therefore, these drugs can be detected in any plasma sample using SPE or UFLC methods.

Separation and purification of heavy rare earth elements by a silica/polymer-based β-aminophosphonic acid resin from chloride media

High-purity heavy rare earths (HREs) are important for promoting the development of cutting-edge materials, but their efficient separation and purification still face significant challenges. Here, a silica/polymer-based β-aminophosphonic acid resin (HEHAEP/SiO2-P) was prepared by vacuum impregnation for the separation of HREs from chloride media. At pH = 2.0, the separation factors (SF) for Er/Ho, Tm/Er, Yb/Tm and Lu/Yb were 2.35, 3.62, 3.14 and 1.23, respectively, surpassing those of some other reported impregnating resins. The maximum adsorption capacity of HEHAEP/SiO2-P for Ho, Er, Tm, Yb and Lu were 33.5, 34.6, 37.0, 38.3 and 43.2 mg/g, respectively. The adsorption process was characterized as homogeneous monolayer chemisorption, driven by entropy in a spontaneous endothermic reaction. Complete desorption of the adsorbed HREs was achieved using 4.0 mol/L HNO3. Employing our strategy, as exemplified by Tm, high-purity Tm2O3 (99.997 %) was obtained by HEHAEP/SiO2-P resin in the column chromatography separation system. FT-IR and XPS analysis demonstrated that both P-OH and PO groups participated in the coordination reaction during the HREs adsorption.

Efficient separation of vanadium and chromium by the complexation with sulfate ions in solvent extraction using EHEHPA

The significant chemical similarity between vanadium and chromium complicates the process of efficient extracting V(Ⅳ) from the solution containing Cr(Ⅲ) to prepare high-purity vanadyl sulfate electrolyte. In this study, the separation of vanadium and chromium with 2-ethylhexyl phosphoric acid-2-ethylhexyl ester (EHEHPA) was enhanced by increasing the concentration of SO42−. Under the extraction equilibrium pH of 2.5, the extraction of Cr(III) was suppressed by increasing the concentration of SO42− anions, which hardly affected the extraction efficiency of V(IV), achieving a separation factor as high as 5780.6 at SO42− concentration of 1.75 mol·L−1. Furthermore, after pretreatment of the water-leaching solution of sodium-roasted vanadium slag, extraction was carried out under the conditions of equilibrium pH of 1.8 and SO42− concentration of about 2.00 mol·L−1, and after stripping, the vanadyl sulfate electrolyte containing 2.12 mol·L−1 of vanadium and only 0.11 mg·L−1 of chromium was obtained. It was proved that Cr(Ⅲ) mainly extracted in the form of CrSO4+ into organic phase by one EHEHPA dimer as [CrSO4(H2O)]+ under higher SO42− concentrations (e.g., ≥1.50 mol·L−1), while Cr(Ⅲ) was extracted by two EHEHPA dimers as Cr3+ without SO42− in the solution. Based on the density functional theory, the complex structures of Cr(III) were optimized and the energy changes of Cr(III) extraction reactions were calculated, indicating the complexation between SO42− and Cr(III) under higher SO42− concentrations resulting in the inhibition of Cr(III) extraction, and thus enhancing the separation of vanadium and chromium.

Lithium extraction via capacitive deionization: AlF3 coated LiMn2O4 spheres for enhanced performance

The escalating demand within the lithium battery sector has intensified the pursuit of efficient methods for lithium's selective extraction from brines. Particularly, LiMn2O4 (LMO) emerges as a prime candidate, celebrated for its robust redox properties and considerable theoretical adsorption capacity. Nonetheless, its application is hampered by structural instability due to Jahn-Teller distortion, which triggers a phase shift from cubic to tetragonal and Mn dissolution, undermining the material's lithium extraction efficiency. In response, this study introduces an innovative, multifunctional amorphous AlF3 coating on LMO spheres, employing a novel synthesis approach combining co-precipitation, solid-phase transformation, and a final AlF3 deposition. This method not only mitigates Mn leaching but also curtails the adverse effects of Jahn-Teller distortion by integrating trace amounts of Al3+ into the LMO lattice, thus fortifying both the surface and bulk structure of the material. Significantly, the AlF3-coated LMO demonstrates an enhanced lithium extraction capacity of 31.5 mg g−1 at 1.2 V with feedwater concentration of 150 mg L−1. Additionally, the optimally coated sample exhibits superior cycling stability, maintaining high-capacity retention and minimal manganese dissolution across multiple absorption-desorption cycles. Furthermore, the optimized electrode exhibits exceptional selectivity for lithium over magnesium in solutions with high Mg2+/Li+ ratios, achieving a notable separation factor of 7.66. Additionally, this electrode demonstrates efficient separation capabilities in synthetic brine, effectively distinguishing Li+ from competing ions such as Na+, K+, Ca2+, and Mg2+, which underscores its substantial potential for effective lithium recovery from complex brines.

Adsorption of vanadium using a new anionic Schiff Base adsorbent and its application to vanadium separation from boiler ash

AbstractBackgroundThis study reports the preparation of 2‐hydroxy‐3‐(4‐(((2‐((2‐(((E)‐4‐(2‐hydroxy‐3‐(trimethylammonio)propoxy)‐3‐methoxybenzylidene)amino)ethyl)amino)ethyl)imino)methyl)‐2‐methoxyphenoxy)‐N,N,N‐trimethylpropan‐1‐aminium (HYM/QA). The adsorbent was employed to extract and concentrate vanadium from its solutions and boiler ash samples.ResultsThe impact of initial dosage, pH, reaction time and temperature on the sorption behavior of V(V) was examined. Under optimal conditions (pH 5, 0.08 g dose, 45 min at room temperature), a sorption capacity of 392.25 mg g−1 was achieved. The uptake of V(V) on HYM/QA was effectively reversed using 1 mol L−1 NaOH, regenerating the material. After six cycles of sorption and elution, the sorption capability remained at 91.4% of its initial value. The efficiency and selectivity of HYM/QA toward V5+ ions were assessed using the separation factor parameter, revealing limited interference from heavy metals such as Mn2+, Cr3+, Pb2+, Si4+, Al3+, NO32−, HCO3− and Zn2+. The uptake process of HYM/QA for V(V) conformed to the Langmuir and Dubinin–Radushkevich isotherm models and the pseudo‐second‐order kinetic model. HYM/QA was characterized by infrared, Brunauer–Emmett–Teller surface area, 1H NMR, 13C NMR and gas chromatography–mass spectrometry analyses, confirming successful preparation. Thermodynamic assessments suggested that the sorption process is endothermic, spontaneous and becoming more favorable with rising temperature.ConclusionThe optimized conditions were used to adsorb vanadium from boiler ash samples, and the obtained vanadium pentaoxide was analyzed and confirmed using various tools, demonstrating the material's effectiveness for vanadium extraction. © 2024 Society of Chemical Industry (SCI).

Ultraselective Macrocycle Membranes for Pharmaceutical Ingredients Separation in Organic Solvents

Separations are core processes in the chemical and pharmaceutical industries. Several steps of fractionation and purification of multicomponent mixtures are required. Membrane technology can operate at fair temperatures, saving energy and processing sensitive compounds. However, breakthroughs require high stability and selectivity beyond those available today. Here, we propose membranes constituted by fully crosslinked crown ethers using interfacial polymerization. The 24 nm-thick nanofilms on robust porous supports exhibit up to 90% higher selectivity than commercially available membranes, with a 90% increase in solvent permeance. The membranes are tested with a complex mixture of structurally diverse solutes containing active pharmaceutical ingredients. The membranes are effective for the total retention and concentration of active pharmaceutical ingredients with molecular weights around 800 g mol–1. The ability to distinguish between smaller molecules in the range between 100 and 370 g mol–1 is confirmed with high separation factors, which could provide a significant advance for the pharmaceutical industry.

Synthesizing LiFePO4 by phosphate & iron recovered from sludge-incinerated ash and Li extracted from concentrated brines

Phosphorus (P) recovered from sludge-incinerated ash (SIA) could be applied to synthesize highly added-value products (FePO4 and LiFePO4) with in situ Fe in SIA. Indeed, LiFePO4 is a future of rechargeable batteries, which makes lithium (Li) highly needed. Alternatively, Li could also be extracted from concentrated brines to face a potential crisis of Li depletion on lands. Based on H3PO4 and Fe3+ co-extracted from the acidic leachate of SIA by tributyl phosphate (TBP), FePO4 (31.2 wt% Fe, 17.6 wt% P and the molar ratio of Fe/P = 0.98) was easily formed only adjusting pH of the stripping solution to 1.6. Interestingly, the organic phase from the first-stage co-extraction process of Fe3+ and H3PO4 could be utilized for Li-extraction from salt-lake brine, based on the TBP-FeCl3-kerosene system, and a good performance (78.7%) of Li-extraction and separation factors (β) (186.0–217.4) were obtained. Furthermore, the compounds with Li-extraction are complex, possibly LiFeCl4∙2TBP, in which Li+ could be stripped to form Li2CO3 by 4.0 M HCl (with a stripping rate up to 83%). Besides, Li2CO3 could also be obtained from desalinated brine by adsorption with manganese oxide ion sieve (HMO) and desorption with HCl. In the two cases, almost pure Li2CO3 products were obtained, up to 99.7 and 99.5 wt% Li2CO3 respectively, after further purification and concentration. Finally, recovered FePO4 and extracted Li2CO3 were synthesized for producing LiFePO4 that had a similar electrochemical property (69.5 and 77.8 mAh/g of the initial discharge capacity) to those synthesized from commercial raw materials.

Synthesis, characterization, and physico-chemical aspects of a new PVC-based quaternary triethanol ammonium chloride anionite for tungsten recovery.

The usability of polyvinyl chloride-based quaternary triethanol ammonium chloride anionite (PVC-TEAC) as a potential extractant for tungstate was investigated to recover tungstate from Gabal Qash Amir, Egypt, assaying 70.91% WO3. Structure elucidation for PVC-TEAC anionite was successfully carried out using several techniques. Experimental measurements, such as pH, agitation time, initial tungsten concentration, anionite dose, co-ions, temperature, and eluting agents, have been optimized. It was found that PVC-TEAC anionite has a maximum capacity of 63 mg per gram. From the distribution isotherm modeling, Langmuir's model fits the experimental results better than Freundlich's, with a theoretical value of 61.728 mg g-1. According to kinetic modeling, the first- and second-order modeling may be regarded as a mixed modeling for a successful adsorption system. Thermodynamic prospects reveal that the adsorption process was predicted as an exothermic, spontaneous, and preferable adsorption at low temperatures. Tungsten ions can be eluted from the loaded anionite, by 1M H2SO4 with a 97% efficiency rate. It was found that PVC-TEAC anionite reveals good separation factor (S.F.) towards most of co-ions. A successful Alkali fusion with NaOH flux followed by tungstate recovery by PVC-TEAC anionite is used to obtain a high-purity tungsten oxide concentrate (WO3), with a tungsten content of 78.3% and a purity of 98.75%.

Quantification of Charge Transport and Mass Deprivation in Solid Electrolyte Interphase for Kinetically‐Stable Low‐Temperature Lithium‐Ion Batteries

AbstractGraphite (Gr)‐based lithium‐ion batteries with admirable electrochemical performance below −20 °C are desired but are hindered by sluggish interfacial charge transport and desolvation process. Li salt dissociation via Li+‐solvent interaction enables mobile Li+ liberation and contributes to bulk ion transport, while is contradictory to fast interfacial desolvation. Designing kinetically‐stable solid electrolyte interphase (SEI) without compromising strong Li+‐solvent interaction is expected to compatibly improve interfacial charge transport and desolvation kinetics. However, the relationship between physicochemical features and temperature‐dependent kinetics properties of SEI remains vague. Herein, we propose four key thermodynamics parameters of SEI potentially influencing low‐temperature electrochemistry, including electron work function, Li+ transfer barrier, surface energy, and desolvation energy. Based on the above parameters, we further define a novel descriptor, separation factor of SEI (SSEI), to quantitatively depict charge (Li+/e−) transport and solvent deprivation processes at Gr/electrolyte interface. A Li3PO4‐based, inorganics‐enriched SEI derived by Li difluorophosphate (LiDFP) additive exhibits the highest SSEI (4.89×103) to enable efficient Li+ conduction, e− blocking and rapid desolvation, and as a result, much suppressed Li‐metal precipitation, electrolyte decomposition and Gr sheets exfoliation, thus improving low‐temperature battery performances. Overall, our work originally provides visualized guides to improve low‐temperature reaction kinetics/thermodynamics by constructing desirable SEI chemistry.

Partition coefficient screening – An effective approach for finding the best conditions for byproduct removal as demonstrated by a bispecific antibody purification case

In recombinant protein purification, differences in isoelectric point (pI)/surface charge and hydrophobicity between the product and byproducts generally form the basis for separation. For bispecific antibodies (bsAbs), in many cases the physicochemical difference between product and byproducts is subtle, making byproduct removal considerably challenging. In a previous report, with a bsAb case study, we showed that partition coefficient (Kp) screening for the product and byproducts under various conditions facilitated finding conditions under which effective separation of two difficult-to-remove byproducts was achieved by anion exchange (AEX) chromatography. In the current work, as a follow-up study, we demonstrated that the same approach enabled identification of conditions allowing equally good byproduct removal by mixed-mode chromatography with remarkably improved yield. Results from the current and previous studies proved that separation factor determination based on Kp screening for product and byproduct is an effective approach for finding conditions enabling efficient and maximum byproduct removal, especially in challenging cases.

Removal of hazardous Aniline Blue dye using a potential Biosorbent – Hen feather

In this research we have successfully removed a highly toxic dye, “Aniline Blue”, from its aqueous solution employing an adsorbent, Hen Feathers. The dye adsorption over Hen Feather was comprehensively studied over ranges of contact time, pH, concentration, and adsorbent dosage, and the optimum values were evaluated. In order to understand the behaviour of the adsorption system, various isotherm models were evaluated at temperatures of 30, 40 and 50 °C. The data obtained from contact time studies were used to test pseudo-first and pseudo-second order kinetic models and it was found that the adsorption follows pseudo-second-order kinetics. Using the Langmuir constant, b, thermodynamic parameters including ΔG°, ΔH° and ΔS° were calculated and it was ascertained that the process is endothermic (positive ΔH°), involves an increase in disorder (positive ΔS°) and is spontaneous (negative ΔG°). The values of the separation factor (r) also confirmed a favourable adsorption process at all three temperatures studied. Overall, it is affirmed that the adsorbent, Hen Feather, acts as highly potent scavenger to remove the dye Aniline Blue from its aqueous solutions.

Quantification of Charge Transport and Mass Deprivation in Solid Electrolyte Interphase for Kinetically-Stable Low-Temperature Lithium-Ion Batteries.

Graphite (Gr)-based lithium-ion batteries with admirable electrochemical performance below -20 °C are desired but are hindered by sluggish interfacial charge transport and desolvation process. Li salt dissociation via Li+-solvent interaction enables mobile Li+ liberation and contributes to bulk ion transport, while is contradictory to fast interfacial desolvation. Designing kinetically-stable solid electrolyte interphase (SEI) without compromising strong Li+-solvent interaction is expected to compatibly improve interfacial charge transport and desolvation kinetics. However, the relationship between physicochemical features and temperature-dependent kinetics properties of SEI remains vague. Herein, we propose four key thermodynamics parameters of SEI potentially influencing low-temperature electrochemistry, including electron work function, Li+ transfer barrier, surface energy, and desolvation energy. Based on the above parameters, we further define a novel descriptor, separation factor of SEI (SSEI), to quantitatively depict charge (Li+/e-) transport and solvent deprivation processes at Gr/electrolyte interface. A Li3PO4-based, inorganics-enriched SEI derived by Li difluorophosphate (LiDFP) additive exhibits the highest SSEI (4.89×103) to enable efficient Li+ conduction, e- blocking and rapid desolvation, and as a result, much suppressed Li-metal precipitation, electrolyte decomposition and Gr sheets exfoliation, thus improving low-temperature battery performances. Overall, our work originally provides visualized guides to improve low-temperature reaction kinetics/thermodynamics by constructing desirable SEI chemistry.