Mechanically Robust and Highly Conductive Poly(ionic liquid)/Polyacrylamide Double-Network Hydrogel Electrolytes for Flexible Symmetric Supercapacitors with a Wide Operating Voltage Range

Flexible electronic devices, such as supercapacitors (SCs), place high demands on the mechanical properties, ionic conductivity, and electrochemical stability of electrolytes. Hydrogels, which combine flexibility and the advantages of both solid and liquid electrolytes, will meet the demand. Here, we report the synthesis of novel poly(ionic liquid)/polyacrylamide double-network (DN) (PIL/PAM DN) hydrogel electrolytes containing different metal salts via a two-step γ-radiation method. The resultant Li2SO4-1.0/PIL/PAM DN hydrogel electrolyte possesses excellent mechanical properties (tensile strength of 3.64 MPa, elongation at break of 446%) and high ionic conductivity (24.1 mS·cm-1). The corresponding flexible SC based on the Li2SO4-1.0/PIL/PAM DN hydrogel electrolyte (SC-Li2SO4) presents improved ion diffusion, ideal electrochemical double-layer capacitor behavior, good rate capability, and excellent cyclic stability. Moreover, symmetric SC-Li2SO4 achieves a wide operating voltage range of up to 1.5 V, with a maximum energy density of 26.0 W h·kg-1 and a capacitance retention of 94.1% after 10,000 galvanostatic charge-discharge cycles, owing to the deactivation of free water molecules by the synergistic effect of PIL, PAM, and SO42-. Above all, the capacitance of SC-Li2SO4 is well-maintained after overcharge, overdischarge, short circuit, extreme temperature, compression, and bending tests, indicating its high security and flexibility. This work reveals the enormous application potential of PIL-based conductive hydrogel electrolytes for flexible electronic devices.

Confinement effect of ionic liquid: Improve of the extraction performance of parent metal organic framework for phthalates

In order to better identify the hazards of pollutants, developing the analytical methods that can sensitively detect and precisely monitor the content of trace pollutants has been the constant pursuit. In this paper, a new solid phase microextraction coating-ionic liquid/metal organic framework (IL/MOF) was obtained through the IL-induced strategy and used for the solid phase microextraction (SPME) process. IL was introduced into metal-organic framework (MOF) cage based on the anion of ionic liquid could interact strongly with the zirconium nodes of UiO-66-NH₂. The introduction of IL not only increased the stability of composite, the hydrophobicity of IL also changed the environment of MOF channel, providing the hydrophobic effect to the targets. The confinement effect of IL effectively improved the extraction performance of parent MOF and the extraction performance of synthesized IL/UiO-66-NH₂ for phthalates (PAEs) were 1.3-3.0 times that of parent UiO-66-NH₂. Thanks to the strong interaction force (hydrogen bonding interaction, π-π stacking, hydrophobic interaction force), the IL/UiO-66-NH₂-coated fiber coupled with gas chromatography-mass spectrometer showed a wide linear ranges (1-5000 ng L^-1) with good correlation (R², 0.9855-0.9987), lower detection limit (0.2-0.4 ng L^-1) and satisfactory recoveries (95.3-119.3%) for PAEs. This article is dedicated to provide another way to improve the extraction performance of material.

Radiation synthesis of imidazolium-based polymeric ionic liquid gel for efficient adsorption of Re(VII) and U(VI) from aqueous solution

In this research, an imidazolium-based polymeric ionic liquid (PIL) gel was effectively synthesized in one step via electron beam (EB) radiation technology. The synthesized gel with gel fraction of 78% under 80 kGy was used for the adsorption and separation of Re(VII) and U(VI). The structure of the gel was characterized by FTIR, SEM, BET, and XPS. Furthermore, batch adsorption was experimented to explore its performance of Re(VII) and U(VI) removal. The two adsorption processes all more fitted the Langmuir isotherm model with the maximum adsorption capacities of 892.9 mg/g for Re(VII) and 243.9 mg/g for U(VI). The adsorption reached equilibrium within 1 min for Re(VII), while within 4 min for U(VI), showing its greatly rapid adsorption rate because of its three-dimensional porous network structure. In addition, the separation experiments of Re/U replied that PIL gel could effectively separate Re(VII) from the simulated uranium leaching solution. Regeneration experiments present the good reusability of PIL gel. This work demonstrated the practical application of EB-radiation technology in the synthesis of PIL gel, which is a promising adsorbent for Re(VII) and U(VI) recovery .

Recent progress in environmental applications of functional adsorbent prepared by radiation techniques: A review

Environmental pollution has been accelerated due to fast urbanization and industrialization, and thus hazardous contaminants removal and valuable metal recovery have become urgent. Adsorption has become a promising technology for water treatment because of its advantages of low-cost, good reusability, low energy consumption, high capacity and high selectivity. Particularly, radiation techniques including radiation induced graft copolymerization and radiation crosslinking have been found to be widely utilized to exploit adsorbents for water treatment. In this review, the current status and progress of adsorbents in environmental pollution in the past decade are summarized, including adsorbents (in form of particles, fiber and fabric, membrane, novel nanomaterials) synthesized by radiation induced graft copolymerization and hydrogel-based adsorbents fabricated by radiation crosslinking. Finally, further perspective on the development and challenge of adsorbents by radiation techniques is also suggested.

Immersion grinding and in-situ polymerization synthesis of poly(ionic liquid)s incorporation into MOF composites as radioactive TcO4- scavenger

Imidazolium-based ionic liquids (ILs) are a promising candidate for efficient separation of radioactive pertechnetate (TcO₄^-) from nuclear waste. However, their effective fixation, availability of active sites and slow adsorption kinetics remain challenges. Here, we incorporated the bisimidazolium-based ILs into porous metal-organic frameworks (MOFs) via a combination of immersion grinding and in-situ polymerization. 3,3'-divinyl-1,1'(1,4-butanediyl) diimidazolium dichloride is tightly bound inside and outside the porous MOFs matrix by uniform immersion grinding, which facilitates the exposure of more adsorption sites and provides channels for the anions to travel through quickly. Solvent-free polymerization reduces environmental pollution and energy consumption. Notably, the composite P[C₄(VIM)₂]Cl₂@MIL-101 possesses an admirable removal efficiency (673 mg g^-1) compared with the pristine poly(ionic liquid)s (215 mg g^-1). Meanwhile, it exhibits fast sorption kinetics (92% in 2 min), good β and γ radiation-resistance, excellent regeneration and eminent removal efficiency in high alkaline conditions (83%). These superior traits endow that P[C₄(VIM)₂]Cl₂@MIL-101 effectively separated TcO₄^- from simulated Hanford Low-activity Waste (LAW) Melter off-gas scrubber solution tested in this work. DFT density functional theory confirms that the strong electrostatic attraction and minimum Gibbs free energy (-6.2 kcal mol^-1) achieve high selective adsorption for TcO₄^-. P[C₄(VIM)₂]Cl₂@MIL-101 demonstrates the considerable potential to remove TcO₄^- from radioactive contaminants.

Efficient and selective adsorption of Au(iii), Pt(iv), and Pd(ii) by a radiation-crosslinked poly(ionic liquid) gel

A PIL gel was prepared for Au(iii), Pt(iv), and Pd(ii) recovery. The PIL gel exhibited fast adsorption rates and excellent selectivity for target ions. Furthermore, the gel could efficiently separate Au(iii) from gold slag leaching solution.

Efficient capture of ReO4- on magnetic amine-functionalized MIL-101(Cr): Revealing from selectivity to mechanism

The efficient decontamination of pertechnetate (⁹⁹TcO₄^-) is an essential task for managing radioactive ⁹⁹Tc in nuclear wastes. Perrhenate, (ReO₄^-), as a nonradioactive analog, exhibits almost identical physicochemical properties as ⁹⁹TcO₄^-. Herein, a novel magnetic amine-functionalized MIL-101(Cr) (NH₂-MIL-101(Cr)@Fe₃O₄) was prepared and used to efficiently remove ReO₄^- from solution for the facile magnetic separation. A series of environmental parameters were considered to investigate the adsorption performance of NH₂-MIL-101(Cr)@Fe₃O₄. Experimental results suggested that NH₂-MIL-101(Cr)@Fe₃O₄ has reached a satisfied adsorption capacity (~401 mg/g) and a very fast adsorption kinetics at pH 7.0. The selectivity for ReO₄^- was maintained even in the presence of interfering anions with relatively high concentrations. ReO₄^- were mainly captured by N-donor sites of the surface-decorated amine via complexation and were trapped in the cavities of modified MIL-101(Cr). NH₂-MIL-101(Cr)@Fe₃O₄ exhibits satisfactory adsorption performance for ReO₄^- and can be conveniently separated from wastewaters after adsorption.

Quaternary phosphonium modified cellulose microsphere adsorbent for 99Tc decontamination with ultra-high selectivity

Decontamination of radioactive TcO₄^- from nuclear wastes is increasingly crucial for spent nuclear fuel reprocessing and environmental remediation. In the presence of a large excess of competitive anions, the selective separation of TcO₄^- is a major challenge for adsorbents. Herein, by using pre-radiation induced grafting polymerization, we have modified economical and environmentally friendly cellulose microspheres to obtain quaternary phosphonium decorated TcO₄^- adsorbents with an ultra-high selectivity, designated CMS-g-VBPPh₃NO₃. The prepared materials show adsorption capacities of 251 mg g^-1 (for the surrogate Re). The selective factor against NO₃^- in 0.5 mol kg^-1 HNO₃ is as high as 168, showing excellent anion-exchange selectivity towards TcO₄^-. Moreover, CMS-g-VBPPh₃NO₃ was packed in column for treating simulated acidic waste solutions containing Cs, Sr, Eu, Zr, Ru, U and Re, and it showed excellent Re separation performance. Tracer amount of ^99mTc experiments showed that comparing to ReO₄^-, CMS-g-VBPPh₃NO₃ has a better adsorption selectivity for TcO₄^-.

Synthesis of a crosslinked poly(ionic liquid) and evaluation of its antimony binding properties

First ever ionic liquid derived sorbent for antimony was synthesised. The charged functional groups of the polymer showed preferential binding and strong affinity for difficult to remove anionic species of antimony. The sorbent was synthesised by crosslinking co-polymerisation of 1-butyl-3-vinylimidazolium bromide with N,N-methylenebis(acrylamide). SEM-EDS analysis showed that the polymer retained the bromide counter ions. Antimony removal properties under wide solution conditions, including the presence of competitor ions, were investigated. Maximum antimony binding and selectivity was at pH 3.0. Variation in saturation capacity with respect to the crosslinker amount matched with the calculated capacity values. Maximum uptake obtained was 4.6 and 3.2 mmol/g for Sb(III) and Sb(V) respectively. Tartrate salt of Sb(III) showed better binding through the interaction of tartrate with the imidazole moieties of the polymer. In less than 15 min, saturation capacity was achieved for Sb(III), while over 90% of uptake was complete for Sb(V). Investigations on sorption mechanism, which included synthesis and comparative evaluation of the non-ionic counterpart polyvinylimidazole as sorbent, indicated the uptake to be through anion exchange. Sb(III) specific binding against Sb(V) was seen in the presence of nitrilotriacetic acid.

Evaluation of an Imidazolium-Based Porous Organic Polymer as Radioactive Waste Scavenger

⁹⁹TcO₄^- is highly radioactive and hazardous to both the environment and public health, meanwhile, it is quite challenging to have it efficiently removed. Herein an imidazolium-based cationic porous polymer (ImPOP-1) is evaluated for removal of TcO₄^-, with nonradioactive ReO₄^- as the surrogate for experimental operation. It is demonstrated that ImPOP-1 is a rare example that can integrate high adsorption capacity (610 mg g^-1), fast kinetics (93.3% in 30 s), and high selectivity (72.9% in 1000 times excess of SO₄^2- ions) in one material. The distribution coefficient K_d is among the top up to 3.2 × 10⁵ mL g^-1. ImPOP-1 also displays high adsorption performance over a wide range of pH values, and removal efficiency up to 64.3% in a highly alkaline solution (3 M NaOH). Recyclability experiments demonstrate that ImPOP-1 can be reused at least four times. The ImPOP-1 also retains a consistent adsorption capacity up to 609 ± 6.1 mg g^-1 between three different batches of samples. In addition, a real-scenario experiment shows that ImPOP-1 can remove 97.4% of ReO₄^- in a simulated Hanford LAW stream.

Efficient uptake of perrhenate/pertechnenate from aqueous solutions by the bifunctional anion-exchange resin

In this work, batch experiments were carried out to explore the sorption properties for perrhenate (ReO4 −, a surrogate for TcO4 −) by two types of commercial bifunctional anion-exchange resins (Purolite A530E and A532E). It is found that these two bifunctional anion-exchange resins could rapidly remove ReO4 − from aqueous solution within 150 min and the maximum sorption capacity for ReO4 − reached as high as 707 and 446 mg/g for Purolite A530E and A532E, respectively. The sorption properties were independent of pH over a wide range from 1 to 13. More importantly, both Purolite A530E and A532E exhibited excellent selectivity for the removal of ReO4 − in the presence of large excess of NO3 − and SO4 2−. Finally, the removal percentage of ReO4 − by these two resins could be >90% and 80%, respectively, from the Hanford low-level waste melter off-gas scrubber simulant stream. Such high selectivity of Purolite A530E and A532E for the removal of ReO4 − might be due to the presence of the long-chain group of –[N(Hexyl)3]+, which favored hydrophobic and large anions such as ReO4 −/TcO4 − rather than NO3 −.

Polymeric ionic liquid gels composed of hydrophilic and hydrophobic units for high adsorption selectivity of perrhenate

The removal of TcO₄⁻ from aqueous solutions has attracted more and more attention recently, and ReO₄⁻ has been widely used as its natural analog. In this work, polymeric ionic liquid gel adsorbents, PC₂-C₁₂vimBr, with high adsorption capacity and selectivity towards ReO₄⁻ were synthesized by radiation-induced polymerization and crosslinking. PC₂-C₁₂vimBr was composed of two monomers: a hydrophobic unit, 1-vinyl-3-dodecylimidazolium bromide for high selectivity, and a hydrophilic unit, 1-vinyl-3-ethylimidazolium bromide for improved kinetics. A gel fraction up to 90% could be achieved under 40 kGy with varied monomer ratios. The adsorption of PC₂-C₁₂vimBr gels for ReO₄⁻ was evaluated by batch adsorption. The PC₂-C₁₂vimBr gel containing 20 mol% hydrophilic unit (named PC₂-C₁₂vimBr-A) could significantly improve the adsorption kinetics, which had an equilibrium time of ca. 24 h. The adsorption capacity obtained from the Langmuir model was 559 mg g⁻¹ (Re/gel). The selective factor against NO₃⁻ was 33.4 ± 1.9, which was more than 10 times higher than that of PC₂vimBr, and it could maintain ReO₄⁻ uptake as high as 100 mg g⁻¹ in 0.5 mol kg⁻¹ HNO₃. The ΔH^Θ and ΔS^Θ of the NO₃⁻/ReO₄⁻ ion-exchange reaction of PC₂-C₁₂vimNO₃-A were −16.9 kJ mol⁻¹ and 29 J mol⁻¹ K⁻¹, respectively, indicating physical adsorption. The adsorption mechanism of ReO₄⁻ onto PC₂-C₁₂vimBr-A gel was ion-exchange, and it could be recovered using 5.4 mol kg⁻¹ HNO₃.

Polymeric ionic liquid gels composed of hydrophilic and hydrophobic units with high adsorption selectivity towards perrhenate were synthesized.

Comparison with adsorption of Re (VII) by two different γ-radiation synthesized silica-grafting of vinylimidazole/4-vinylpyridine adsorbents

Two silica gel based adsorbents for Re (VII), i.e. SS-MPTS-VIMH and SS-MPTS-VPQ, were synthesised. Silica gel was used as the matrix for γ-radiation grafting, and the monomer of 1-vinyl imidazole (VIM) and 4-vinylpyridine (4-VP) was grafted onto the silica silanized by methacryloxy propyl trimethoxyl silane, respectively. A VIM concentration of 2molL^-1 and an absorbed dose of 30kGy were the optimal grafting conditions for adsorbent SS-MPTS-VIM, and a 4-VP concentration of 4molL^-1 and an absorbed dose of 40kGy were the optimal grafting conditions for adsorbent SS-MPTS-VP. At the certain condition, the grafting yield of SS-MPTS-VIM was 30.1% and that of SS-MPTS-VP was 21.0%. The adsorption capacity of adsorbent SS-MPTS-VIMH was 145.99mgg^-1 and that of SS-MPTS-VPQ was 71.08mgg^-1 according to the Langmuir model. The adsorbent SS-MPTS-VPQ had better adsorption properties of acid resistance and anti-interference than SS-MPTS-VIMH. Dynamic column experiments showed that protonated adsorbent SS-MTPS-VIMH could be recycled with good performance while quaternized adsorbent SS-MPTS-VPQ could not. The adsorbent SS-MPTS-VIMH belongs to weak anion exchange adsorbent and SS-MPTS-VPQ belongs to strong anion exchange adsorbent. This study paves a way to the synthesis and application of a novel silica base adsorbents for Re (VII).

Design of Graphene- and Polyaniline-Containing Functional Polymer Hydrogel as a New Adsorbent for Removal of Chromium (VI) Ions

Hydrogels find applications in various fields, and the ever-growing spectrum of available monomers, crosslinking, and nanotechnologies widen the application of polymer hydrogels. Herein, we describe the preparation of a new graphene (G)- and polyaniline (PANI)-containing functional polymer gel (G/PANI/FG) through a facile crosslinking copolymerization approach. Several characterization techniques such as field-emission scanning electron microscopy, Fourier-transform infrared, and X-ray photoelectron spectroscopy were employed to understand the physicochemical characteristics of the G/PANI/FG. The new G/PANI/FG was used as an adsorbent for chromium (VI) and exhibited the highest Cr (VI) removal efficiency (~97%). The inclusion of G and PANI in the gel results in high surface area, 3D porous structure, and Cr (VI)-chelating amine sites, which enhanced the Cr (VI) removal efficiency and thermal stability of the gel adsorbent. The results of our study revealed that G/PANI/FG is suited for the removal of Cr (VI) from aqueous solution.