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Poly(ionic) liquid (PIL) augmented membranes were fabricated through self-polymerization of 2-vinyl pyridine and 4-vinyl pyridine followed by dopamine triggered polymerization and bridging with inert polyamide support. The resulting membranes acquired a positive surface charge with a high degree of hydrophilicity. Fourier transformed Infra-red (FTIR) and Energy dispersive X-ray (EDX) spectroscopic investigation revealed the successful augmentation of PIL surface layer, whereas surface morphology was investigated through scanning electron microscopy (SEM) imaging. This manuscript demonstrates pi electron-induced separation of dyes with the trend in permeability: Coomassie Brilliant Blue G (CBBHG) &gt, Remazol Brilliant Blue R (RBBR) &gt, Eichrome Black T (EBT) &gt, Congo Red (CR). CBBG exhibited extended conjugation over large aromatic domain. RBBR and EBT were associated withtheelectron-donating -NH2 group and electron-withdrawing -NO2 group, respectively, hence pi electron density on aromatic ring varied. The steric repulsion between two pairs of ortho hydrogens (Hs) in biphenyl moieties of CR resulted in deviation of planarity and hence aromaticity leading to the lowest permeability. The sugar fractionation followed the trend: Galactose &gt, Mannose &gt, Fructose &gt, Glucose &gt, Xylose. More hydroxyl (-OH) groups in sugars and their conformational alignment in the same direction, exhibited more lone pair of electrons leading to more interaction with PIL and hence better permeability. Pentose showed poorer permeation than hexose, whereas aldose showed better permeation than ketose.

Ultrafiltration membranes, that respond to an external magnetic field and local temperature have been developed. Surface-initiated activator-generated electron transfer (AGET) atom transfer radical polymerization (ATRP) has been used to graft poly(N-isopropylacrylamide) (PNIPAm) from the surface of 300 kDa regenerated cellulose membranes. The polymerization initiator was selectively attached to the entire membrane surface, only the outer membrane surface or only the inner pore surface. A superparamagnetic nanoparticle was attached to the end of the polymer chain. The DI water flux as well as the flux and rejection of bovine serum albumin were investigated in the absence and presence of a 20 and 1000 Hz oscillating magnetic field. In an oscillating magnetic field, the tethered superparamagnetic nanoparticles can cause movement of the PNIPAm chains or induce heating. A 20 Hz magnetic field maximizes movement of the chains. A 1000 Hz magnetic field leads to greater induced heating. PNIPAm displays a lower critical solution temperature at 32 °C. Heating leads to collapse of the PNIPAm chains above their Lower Critical Solution Temperature (LCST). This work highlights the versatility of selectively grafting polymer chains containing a superparamagnetic nanoparticle from specific membrane locations. Depending on the frequency of the oscillating external magnetic field, membrane properties may be tuned.

Forward osmosis (FO) is an important desalination method to produce potable water. It was also used to treat different wastewater streams, including industrial as well as municipal wastewater. Though FO is environmentally benign, energy intensive, and highly efficient; it still suffers from four types of fouling namely: organic fouling, inorganic scaling, biofouling and colloidal fouling or a combination of these types of fouling. Membrane fouling may require simple shear force and physical cleaning for sufficient recovery of membrane performance. Severe fouling may need chemical cleaning, especially when a slimy biofilm or severe microbial colony is formed. Modification of FO membrane through introducing zwitterionic moieties on the membrane surface has been proven to enhance antifouling property. In addition, it could also significantly improve the separation efficiency and longevity of the membrane. Zwitterion moieties can also incorporate in draw solution as electrolytes in FO process. It could be in a form of a monomer or a polymer. Hence, this review comprehensively discussed several methods of inclusion of zwitterionic moieties in FO membrane. These methods include atom transfer radical polymerization (ATRP); second interfacial polymerization (SIP); coating and in situ formation. Furthermore, an attempt was made to understand the mechanism of improvement in FO performance by zwitterionic moieties. Finally, the future prospective of the application of zwitterions in FO has been discussed.

Extraction of actinide (Pu4+, UO2 2+, Am3+) and lanthanide (Eu3+) ions was carried out using different diglycolamide (DGA) ligands with systematic increase in the alkyl chain length from n-pentyl to n-dodecyl. The results show a monotonous reduction in the metal ion extraction efficiency with increasing alkyl chain length and this reduction becomes even more prominent in case of the branched alkyl (2-ethylhexyl) substituted DGA (T2EHDGA) for all the metal ions studied. Steric hindrance provided by the alkyl groups has a strong influence in controlling the extraction behavior of the DGAs. The distribution ratio reduction factor, defined as the ratio of the distribution ratio values of different DGAs to that of T2EHDGA, in n-dodecane follows the order UO2 2+ > Pu4+ > Eu3+ > Am3+. Complexation of Nd3+ was carried out with the DGAs in methanol by carrying out UV-vis spectrophotometric titrations. The results indicate a significant enhancement in the complexation constants upon going from methyl to n-pentyl substituted DGAs. They decreased significantly for DGAs containing alkyl substituents beyond the n-pentyl group, which corresponds to the observed trend from the solvent extraction studies. DFT-based calculations were performed on the free and the Nd3+ complexes of the DGAs both in the gas and the solvent (methanol) phase and the results were compared the experimental observations. Luminescence spectroscopic investigations were carried out to understand the complexation of Eu3+ with the DGA ligands and to correlate the nature of the alkyl substituents on the photophysical properties of the Eu(III)-DGA complexes. The monoexponential nature of the decay profiles of the complex revealed the predominant presence of single species, while no water molecules were present in the inner coordination sphere of the Eu3+ ion.

Electric responsive membranes have been prepared by controlled surface grafting of poly (ionic liquid) (PIL) on the commercially available regenerated cellulose ultrafiltration membrane. The incorporation of imidazolium ring on membrane surface was evidenced by FTIR (Fourier transformed infra-red) and EDX (energy-dispersive X-ray) spectroscopy. The PIL grafting resultedin a rougher surface, reduction in pore size, and enhancement in hydrophilicity. The interaction of the electric field between the charged PIL brush and the oscillating external electric field leads to micromixing, and hence it is proposed to break the concentration polarization. This micromixing improves the antifouling properties of the responsive membranes. The local perturbation was found to decrease the water flux, while it enhanced protein rejection. At a higher frequency (1kHz) of the applied electric field, the localized heating predominates compared to micromixing. In the case of a lower frequency of the applied electric field, more perturbation can lead to less permeability, whereas it will have a better effect in breaking the concentration polarization. However, during localized heating at a higher frequency, though perturbation is less, a heating induced reduction in permeability was observed. The electric field response of the membrane was found to be reversible in nature, and hence has no memory effect.

Membrane-based processes are attractive for treating oily wastewaters. However, membrane fouling due to the deposition of oil droplets on the membrane surface compromises performance. Here, real-time observation of the deposition of oil droplets by direct confocal microscopy was conducted. Experiments were conducted in dead-end and crossflow modes. Base NF 270 nanofiltration membranes as well as membranes modified by grafting poly(N-isopropylacrylamide) chains from the membrane surface using atom transfer radical polymerization were investigated. By using feed streams containing low and high NaCl concentrations, the grafted polymer chains could be induced to switch conformation from a hydrated to a dehydrated state, as the lower critical solution temperature for the grafted polymer chains moved above and below the room temperature, respectively. For the modified membrane, it was shown that switching conformation of the grafted polymer chains led to the partial release of adsorbed oil. The results also indicate that, unlike particles such as polystyrene beads, adsorption of oil droplets can lead to coalescence of the adsorbed oil droplets on the membrane surface. The results provide further evidence of the importance of membrane properties, feed solution characteristics, and operating mode and conditions on membrane fouling.

Direct contact membrane distillation (DCMD) has been conducted to treat hydraulic fracturing-produced water using polyvinylidenedifluoride (PVDF) membranes. Tailoring the surface properties of the membrane is critical in order to reduce the rate of adsorption of dissolved organic species as well as mineral salts. The PVDF membranes have been modified by grafting zwitterion and polyionic liquid-based polymer chains. In addition, surface oxidation of the PVDF membrane has been conducted using KMnO4 and NaOH. Surface modification conditions were chosen in order to minimize the decrease in contact angle. Thus, the membranes remain hydrophobic, essential for suppression of wetting. DCMD was conducted using the base PVDF membrane as well as modified membranes. In addition, DCMD was conducted on the base membrane using produced water (PW) that was pretreated by electrocoagulation to remove dissolved organic compounds. After DCMD all membranes were analyzed by scanning electron microscopy imaging as well as Energy-Dispersive X-Ray spectroscopy. Surface modification led to a greater volume of PW being treated by the membrane prior to drastic flux decline. The results indicate that tailoring the surface properties of the membrane enhances fouling resistance and could reduce pretreatment requirements.

Ionic liquid-based solvent systems containing diglycolamide-functionalized calix[4]arenes (C4DGAs) are efficient for actinide ion extraction from nitric acid feeds. Therefore, the radiolytic stability of three C4DGAs (wide-rim, narrow-rim and both side DGA-functionalized calix[4]arenes) and TODGA (N,N,N′,N′-tetraoctyldiglycolamide) (used for comparison purpose), was evaluated by exposing their solutions in an ionic liquid as well as a 95:5 mixture of n-dodecane + isodecanol to gamma radiation up to an absorbed dose of 1000 kGy. Liquid-liquid extraction studies were carried out using 241Am as a radiotracer. Apart from a decrease in the DAm values, ascribed to radiolytic degradation, FT-IR, EPR and GC-MS studies were carried out to characterize the degraded species. The different extractants are less sensitive to radiolytic degradation in the ionic liquid than in the molecular diluent.

The activators generated electron transfer (AGET) method coupled with atom transfer radical polymerization (ATRP) is shown to be a simple and well controlled approach for surface-initiated polymerization of 2-hydroxyethyl methacrylate (HEMA) on regenerated cellulose (RC) membranes. The AGET-ATRP method has been optimized with respect to the initiator concentration, the polymerization reaction time and the reducing agent (activator) concentration. Control of polymer grafting on the external membrane surface versus the internal pore surface of RC ultrafiltration membranes was investigated using different pore filling solvents having a wide range of viscosity and reactivity during ATRP initiator immobilization via acylation of RC hydroxyl groups. The effectiveness of the pore filling solvent in limiting grafting inside the membrane pores was found to depend on both its viscosity and reactivity. Rejection of BSA and dextran was used to probe changes in pore size. Glycerol was found to be the most effective pore filling solvent, indicated by a significant degree of modification of the membrane surface with grafted polyHEMA but only a very minor increase in solute rejection.

Three diglycolamide-functionalized poly(propylene imine) diaminobutane dendrimers, viz., zero generation (LI), first generation (LII), and second generation (LIII), were synthesized and evaluated for their complexation ability towards trivalent actinides and lanthanides. The distribution coefficient (D) of Am3+ with 1.0 mmol L−1 ligand in 3 M HNO3 follows the order: 0.1 (LI) < 42 (LII) < 110 (LIII). Slope analysis indicated the stoichiometry of the extracted complexes as: 1 : 2 (M : L) for LI and 1 : 2 (M : L) for both LII and LIII. A complexation study of a representative lanthanide (Eu3+) with the three ligands by absorption spectroscopy and luminescence spectroscopy confirmed the formation of the above stoichiometry. The stability constants (log β) for the ML complexes of Eu3+ with the three ligands were determined to be 5.2 ± 0.03, 5.3 ± 0.01, and 5.4 ± 0.02 for LI, LII, and LIII, respectively. The identical log β values (within experimental error) for all the ligands indicate that the complexation is not affected by the branching of the ligands. The metal/ligand complex formation was explained with the help of spectroscopic data.

Three benzene-centered tripodal diglycolamides (Bz-T-DGAs) were synthesized and evaluated for actinide, lanthanide, and fission product ion extraction. 1,3,5-Triethylbenzene-based tripodal DGA (LI) showed high distribution ratio (D) values for Am3+ and Eu3+ in a mixture of 95% n-dodecane and 5% iso-decanol at 3 M HNO3. Eu/Am separation factors, in the range of 8–10, were obtained at 1 M HNO3 which decreased at higher acidities with the exception of LII which did not show much change. Benzene-1,3,5-triamide-based tripodal DGA (LII) exhibited a high D-value for Pu4+ compared to the other ligands. Slope analysis showed the formation of 1 : 1 or 1 : 2 complexes is dependent on the ligand. The nature of the complexes was further studied with luminescence spectroscopy (Eu complexes) and DFT calculations (Am complexes).

Diglycolamide-functionalized calix[4]arenes (C4DGAs) with varying structural modifications were evaluated for actinide complexation from their extraction behavior toward actinide ions such as UO2(2+), Pu(4+), PuO2(2+), and Am(3+) in the room temperature ionic liquid (RTIL) 1-n-octyl-3-methylimidazolium bis(trifluoromethane)sulfonamide (C8mimNTf2). The formation constants were calculated for Am(3+) which showed a significant role of ligand structure, nature of substituents, and spacer length. Although the alkyl substituents on the amidic nitrogen increase the extraction efficiency of americium at lower acidity because of the inductive effect of the alkyl groups, at higher acidity the steric crowding around the ligating site determines the extraction efficiency. All C4DGAs formed 1:1 complexes with Am(3+) while for the analogous Eu(3+) complexes no inner sphere water molecules were detected and the asymmetry of the metal ligand complex differed from one another as proved by time-resolved laser induced fluorescence spectroscopy (TRLIFS). Thermodynamic studies indicated that the extraction process, predominant by the Am(3+)-C4DGA complexation reaction, is exothermic. The unique role of the medium on Am(3+) complexation with the C4DGA molecules with varying spacer length, L-IV and L-V, was noticed for the first time with a reversal in the trend observed in the RTIL compared to that seen in a nonpolar molecular diluent like n-dodecane. Various factors leading to a more preorganized structure were responsible for favorable metal ion complexation. The solvent systems show promise to be employed for nuclear waste remediation, and sustainability options were evaluated from radiolytic stability as well as stripping studies.

A systematic study was carried out to understand the complexation of a diglycolamide functionalized task-specific ionic liquid (DGA-TSIL) and its molecular analogue, (tetraoctyldiglycolamide) TODGA with uranyl ion by cyclic voltammetry, solvent extraction and UV–Vis spectroscopy. Significant shifts of cathodic peak potential towards more positive values as compared to the uranyl ion in a room temperature ionic liquid-diluent, [C8mim][Br] were attributed to the complexation of it with the ligands. The order of diffusion coefficient values determined gave the idea of the bulkiness of the U bearing species. In the case of DGA-TSIL, the measurable, relatively slower kinetics in ionic liquid observed by both electrochemical and biphasic extraction techniques was attributed to high viscosity coefficient of the ionic liquid. The complexation reaction with U(VI) was found to follow the first order kinetics with a rate constant of 4.8 × 10−4 s−1. Titration data from cyclic voltammograms for a series of additions of the ligand to a fixed concentration of uranyl ion indicated that uranyl ion forms 1:1 complexed species with DGA-TSIL with the formation constant of 1.0 × 103 M−1 which agreed well with that obtained by slope analysis from biphasic extraction results. Difference in the UV–Vis spectra in terms of shifts of peak positions and relative peak intensities could possibly indicate the presence of different species of the uranyl ion in the RTIL with and without the ligand. It was also proposed that the bond (Odouble bond; length as m-dashUdouble bond; length as m-dashO) becomes weaker on complexation due to the approach of the ligand towards the metal ion, partially neutralizing the charge on the uranyl moiety. The symmetric stretching frequency calculated from UV–Vis spectra was in conformity of the above fact.

A cyclic voltammetric study on Np(IV) complexes with task-specific ionic liquid with 3-dodecylimidazolium cation appended with diphenylcarbamoylmethylphosphine oxide and bis(trifluoromethyl-sulfonyl)-imide anion dissolved in the room temperature ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)-imide has been carried out. The results are compared with its molecular entity, viz., octyl(phenyl)carbamoylmethylphosphine oxide dissolved in the same diluent. The diffusion coefficient values were determined using its variation with scan rate. The standard rate constant values were also computed. The activation energy for diffusion and thermodynamic parameters for the redox reactions of the Np complexes were determined and compared.

This paper reports a first-ever cyclic voltammetric study and the electrochemical characterization of Np(IV) complexes with task-specific ionic liquid with appended diglycolamide (DGA-TSIL) ligand dissolved in the room-temperature ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C4mimNTf2). The results are compared with molecular entity, N,N,N′,N′-tetraoctyl diglycolamide (TODGA) dissolved in the same diluent. The diffusion coefficient (D) values were determined using the Randles–Sevcik equation. The standard rate constant (k s) values were also computed for the Np(IV)/Np(III) electrode redox reaction. The activation energy for diffusion (E a) and thermodynamic parameters for the redox reactions of the Np complexes were determined and compared.

Two new diglycolamide-based task-specific ionic liquids (DGA[BOND]TSILs) were evaluated for the extraction of actinides and lanthanides from acidic feed solutions. These DGA[BOND]TSILs were capable of exceptionally high extraction of trivalent actinide ions, such as Am3+, and even higher extraction of the lanthanide ion, Eu3+ (about 5–10 fold). Dilution of the DGA[BOND]TSILs in an ionic liquid, C4mim+⋅NTf2−, afforded reasonably high extraction ability, faster mass transfer, and more efficient stripping of the metal ion. The nature of the extracted species was studied by slope analysis, which showed that the extracted species contained one NO3− anion, along with the participation of two DGA[BOND]TSIL molecules. Time-resolved laser fluorescence spectroscopy (TRLFS) analysis showed a strong complexation with no inner-sphere water molecule in the EuIII[BOND]DGA[BOND]TSIL complexes in the presence and absence of C4mim+⋅NTf2− as the diluent. The very high radiolytic stability of DGA[BOND]TSIL 6 makes it one of the most-efficient solvent systems for the extraction of actinides under acidic feed conditions.

A novel solvent system containing a newly synthesized both-side diglycolamide-functionalized calix[4]arene (L-I) in a room temperature ionic liquid showed highly efficient extraction of actinides and a remarkable acid concentration independent extraction of trivalent actinide ion, Am(3+) suggesting its possible use for high level radioactive waste remediation. The nature of the complexes was ascertained by slope analysis, luminescence spectroscopic investigations and from the thermodynamic parameters. The sustainability of the solvent system for long term applications was also investigated.

A definition for a document type within an organization represents an organizational norm about the way the organizational actors represent products and supporting evidence of organizational processes. Generating a good organization-specific document structure is, therefore, important since it can capture a shared understanding among the organizational actors about how certain business processes should be performed. Current tools that generate document type definitions focus on the underlying technology, emphasizing tags created in a single instance document. The tools, thus, fall short of capturing the shared understanding between organizational actors about how a given document type should be represented. We propose a method for inferring organization-specific document structures using multiple instance documents as inputs. The method consists of heuristics that combine individual document definitions, which may have been compiled using standard algorithms. We propose a number of heuristics utilizing artificial intelligence and natural language processing techniques. As the research progresses, the heuristics will be tested on a suite of test cases representing multiple instance documents for different document types. The complete methodology will be implemented as a research prototype