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High chemical oxygen demand (COD) and a strong color, which primarily originates from desizing and dyeing operations, are two major removal objectives in textile wastewater treatment. In this study, crosslinking-induced precipitation via the covalent bonding between –OH groups of PVA and vinyl sulfone groups of reactive dyes is proposed to simultaneously remove poly(vinyl alcohol) (PVA) and reactive dyes. Due to the nucleophilic addition reaction under an alkaline condition, PVA polymers can be efficiently crosslinked by dye molecules and destabilized in the presence of alkali and Na2SO4. Additionally, due to the high coagulation efficiency under the alkaline conditions, MgSO4 was used as a coagulant to facilitate the removal of the residual color after precipitation. After a two-step process, whereby coagulation was followed by crosslinking-induced precipitation, the maximum efficiencies of the removal of COD, PVA, and color attained 88.9%, 86.3%, and 99.2%, respectively, when the PVA monomer/RB5 mole ratio was 400. We hope that this technically feasible, highly efficient, and cost-effective process provides a basis for the practical application of the simultaneous treatment of desizing and dyeing wastewater.

Utilization of self-healing chemistry and biomimetic structure design, to develop stretchable conductors that are self-healing and recyclable, is of great interest. Herein, we utilize small molecular (triethanolamine, TEA) instead of common polymer segments as a spacer and cross-linker, which could render the dynamic covalent/noncovalent thermosets with higher density of reversible bonds (H-bonds and disulfide bonds) and more cross-linked points through controlling mole fraction due to more hydroxyl group per molecular weight of TEA. The as-prepared thermosets exhibit excellent thermal stability, shape memory effect, recyclability and healing efficiency at relatively moderate temperature. Then, a series of mechanically and electrically self-healing conductive tendrils composed of self-healing/shape memory polymers and conductive percolation networks are fabricated, which possess enhanced conductivity retention capability under stretching states. Moreover, our designed helical-structured conductors can be not only rehealed but also recycled and reprocessed due to the simultaneous destruction and reestablishment of the reversible bonds. Strikingly, the fabrication process of self-healing conductive tendrils is compatible to the conventional technique of conductors including silk-screen printing and adhesive bonding technique. This biomimetic approach opens a promising pathway to fabricate wearable intelligent devices with versatile functions.

Developing stable open-pore sorbents with high porosity to efficiently capture radiotoxic iodine from the waste streams of nuclear is highly desirable in addressing the environmental issues. Here, we report three highly stable covalent triazine polymers with the same chemical composition while bearing different degree of crystallinity and pore structures toward iodine capture. The best adsorption capacity of 4.31 g g−1 towards iodine vapor is achieved by CTF-1@ZnCl2 composed of ordered skeletons and uniform 1D open channels. In comparison, the amorphous samples, i.e. CTF-1@ZnCl2·H2O and CTF-1@TFMS, display moderate uptakes of iodine up to 2.41 and 1.18 g g−1, respectively. Similar trend is also demonstrated in the case of iodine retaining in hexane, where the open pore array in the crystalline CTF-1@ZnCl2 contributes significantly to its high adsorption capacity when compared to those interpenetrated and/or low-degree-crosslinked networks. The CTF-1@ZnCl2 after treating by organic solvent/dilute base/acid still maintain the capacities in iodine adsorptions with good recyclability, demonstrating their excellent structural stability. This study illustrates the importance of ordered skeletons and uniform 1D open channels in the adsorption process, which may provide a potential platform targeting for solving key environmental issues.

Covalent organic frameworks (COFs) materials with designed skeleton structure and controlled pore size are a new class of adsorbent materials for environment remediation. Here, we synthesize two amide-based COFs materials via a polymerization reaction of acyl chloride and amino groups by mechanical ball milling at room temperature for Pb2+ removal as adsorbents. Two types of diamine monomers are selected to construct COFs with different framework structure and functional groups contents, i.e. COF-TP from aromatic diamine and COF-TE from linear diamine. The as-prepared COFs materials display typical lamellar structure, and the amide groups on COFs skeleton are confirmed to behave as active adsorption sites for Pb2+ capture via multi-coordination. COF-TE exhibits superior Pb2+ adsorption capacity to COF-TP, because that less aromatic skeleton and weak π-π stacking of COF-TE facilitate higher internal diffusion of Pb2+ adsorption. Meanwhile, the higher amide group content on COF-TE leads to its higher saturated adsorption capacity of 185.7 mg/g than COF-TP of 140.0 mg/g. Finally, great recycling stability of Pb2+adsorption allows the amide-based COFs materials to be promising adsorbents for heavy metal Pb2+ removal or recovery.

Amine containing polymers (ACPs) were synthesized by heating glyoxal and melamine under argon conditions. The batch characterization, including SEM, FTIR, XRD and XPS techniques, indicated that ACPs had various nitrogen-containing functional groups. The batch experiments indicated that ACPs presented the high removal performances (Qmax = 250 mg/g, calculated by Langmuir model), well stability, strong salt tolerance and great regeneration cycle toward U(VI). XPS analysis confirmed the coordination of U(VI) with nitrogen- or oxygen-containing groups via covalent bonding. The theoretical calculations revealed that the binding energies of U-N, U-O and U-C were −27.49, −16.94 and −11.81 kcal/mol, respectively, indicating that U(VI) was tended to combine with nitrogen-containing groups. These observations suggested that ACPs can be regarded as a promising adsorbent for immobilization and pre-concentration of U(VI)-containing wastewater in environmental cleanup.

Controlled release formulations can reduce the losses of pesticides and prolong their effective duration. In this work, a novel pH responsive pesticide delivery system based on kasugamycin-conjugated ZnO quantum dots (KAS-ZnO QDs) was established via a cleavable benzoic–imine covalent bond. The as-prepared KAS-ZnO QDs could protect KAS against photodegradation effectively due to the UV shielding effect of KAS-ZnO QDs. The KAS and Zn2+ released from KAS-ZnO QDs in the acid condition could achieve a synergistic antimicrobial activity. The greenhouse experiment confirmed that application of KAS-ZnO QDs had a longer duration and a better antimicrobial activity against bacterial fruit blotch compared to KAS and NH2-ZnO QDs treatments, and showed no any toxicity to plants. Thus, pH-responsive KAS-ZnO QDs could achieve a synergistic antimicrobial effect and offer a new approach to manage plant diseases.

The transformations of water-stable C60 clusters (nC60) to oxidized C60 derivatives via photoreactions and ground-state reactions have been described as critical processes in understanding the ultimate environmental fate of fullerene-based materials. However, (photo)oxidation of aqueous-based C60 (as water stable, nanoscale aggregates termed nC60) with hydrogen peroxide (H2O2) and/or hydroxyl radical ( OH), common environmental oxidants, has not been fully explored. To address this, the aqueous physicochemical transformations of C60 (as nC60 aggregates) in the presence of H2O2 and/or OH in both photoexcited-state and ground-state under environmentally relevant conditions are quantitatively described. Results show that nC60 undergoes facile oxidation in the presence of H2O2 under UVA irradiation but not under dark conditions, and the oxidation reaction rates increase with effective OH concentration (via photodecomposition of H2O2), while being inversely related to solution pH. Product characterization via dynamic light scattering, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, total organic carbon, high-performance liquid chromatography, and octanol-water partition experiments collectively describe resulting C60 derivatives with new covalent oxygen functionality which are also relatively more hydrophilic. For all cases, photoirradiation was observed to significantly enhanced the rates and extent of C60 oxidation.

In this study, polyvinyl pyrrolidine intercalated molybdenum disulfide (PVP/MoS2) with well-interconnected nanosheets were successfully prepared by an effective and versatile one-step hydrothermal strategy. The structural characterization indicated that the PVP molecules were intercalated into MoS2 to produce widened interlayer spacing. The obtained PVP/MoS2 nanomaterials exhibited impressive adsorption performance. Specifically, the maximum adsorption capacity of U(VI) on PVP/MoS2 (∼117.9 mg/g) was apparently superior than that of pristine MoS2 (∼23.7 mg/g) at 298 K and pH = 4.5, which might be related to the enlarged specific surface area and extensive functional groups of PVP/MoS2. The kinetics investigation showed that the uptake of U(VI) with PVP/MoS2 was ultrafast and the adsorption equilibrium could be reached within 10 min. The enrichment of U(VI) on PVP/MoS2 was caused by the existence of UO2-S covalent bonds and surface complexation with PVP, which was jointly verified by systematic investigation of FT-IR, XPS and DFT calculations. These findings were intriguing for both evaluating the adsorption performance of PVP/MoS2 and advancing other polymer interacted layered metal sulfides potential applications in the field of radioactive water treatment.

A simple and selective photoelectrochemical method was reported for 5-hydroxymethylcytosine (5hmC) detection in genomic DNA based on DNA methyltransferase (MTase) catalytic covalent bonding of –CH2OH of 5hmC with thiol compounds, where WS2 nanomaterial was used as a photoactive material, polydopamine (PDA) was employed as a solid-phase electron donor, phos-tag-biotin was used as bridge to link 5hmC and streptavidin. PDA was attached to 4-mercaptophenulboronic acid (MPBA) via the covalent bonding between its vicinal diol and the boracic acid of MPBA. Then, under the catalytic effect of M. HhaI MTase, 5hmC deoxyribonucleotide was captured on electrode surface through the covalent bonding between –CH2OH and –SH. Afterwards, phos-tag-biotin, a kind of specific reagent for phosphate group, was further captured through the specific bonding between the phosphate group of 5hmC deoxyribonucleotide and phos-tag-biotin. Subsequently, based on the “bridge” role of phos-tag-biotin, streptavidin was further modified on electrode surface to further block the transfer of photogenerated-electron to electrode surface. The photocurrent shows linear relationship with the logarithm value of 5hmC concentration in the range from 0.01 to 100 nM, and the detection limit of 4.12 pM (3σ). The developed method presents high detection specificity, which can discriminate 5-methylcytosine and 5hmC. Moreover, the applicability of this photoelectrochemical method was evaluated by detecting 5hmC content change in maize seedlings leaves and chicken embryo fibroblast cell.

This study exploits an effective mechanochemical process (termed as reaction milling) to conduct Schiff-based coupling reaction with melamine and terephthalaldehyde for the synthesis of covalent organic polymer (RM-COP) as the carbon skeleton and the derivative phosphorus doped material (RM-COP-PA). Comparing with the tradition solvothermal method with reaction time of 3 days under 120 °C, the newly developed reaction milling method significantly shorten the reaction time of the synthesis to 3 h under room temperature as well as bypassing the usage for hazardous solvents. The space-time yield of the developed reaction milling method for synthesis of the bifunctional electrocatalytic precursor reaches 189 kg m−3 day−1. Significantly, the optimal products followed by further carbonization (RM-COP-PA-900) demonstrated excellent bifunctional electrocatalytic activities for an efficient ORR performance with similar commercialized Pt/C half-potential of 841 mV vs RHE as well as an IrO2-like OER activity with a potential of 1.69 V at 10 mA cm−2 in alkaline media, which is better than most metal-free bifunctional catalysts. Moreover, the obtained RM-COP-PA-900 exhibits much better durability and resistance to crossover effect even than the commercial 20 wt% Pt/C catalysts. Therefore, this work will open up a rapid, solvent-free and scalable approach for, but not limit to, highly efficient electrocatalysts.

Covalent organic frameworks (COFs) are burgeoning crystalline porous materials that are constituted with organic building units and covalent bonds. The pre-designable porous structures make a platform for solving energy and environmental problems. This article systematically presents the basic design principle of COFs and introduces the applications in energy and environment fields, for instance, gas storage, energy storage, photoconduction, and catalysis. We also discussed the gas storage conditions and the strategies to improve the hydrogen storage. Finally, we proposed a scheme for improving the storage capacity of lithium-ion (Li-ion) batteries with COFs and the use of COFs to remove Hg in water, and as a catalyst to make rational use of solar energy.

There is an increasing interest in using l -asparaginase in medical fields and food processing industries. Enzyme immobilization is an attractive field to improve l -asparaginase activity and stability. Graphene oxide (GO) is a promising candidate for enzyme immobilization due to its large specific surface area. In this study, GO was first functionalized with l -aspartic acid (GO-Asp), and then l -asparaginase was immobilized on the GO-Asp either physically or through chemical conjugation. A significant enzyme loading was achieved through covalent immobilization (100% immobilization efficiency). Stability of free and the immobilized l -asparaginase was examined at various temperatures (20–60 °C) and pH (5–9). The covalently immobilized l -asparaginase showed higher enzyme activity than free enzyme at pH 8 with the maximum recovered activity of 100%, 90.5% and 40.6% after 24 h of incubation at 20 °C, 40 °C and 60 °C, respectively. In addition, the covalently immobilized l -asparaginase on GO-Asp showed 42% recovered activity after eight continuous reaction cycles at 60 °C. The kinetic parameters of the immobilized and free enzyme were also calculated, indicating no significant changes in the enzyme affinity through covalent conjugation. The results clearly reflect the suitability of GO-Asp as a nanosheet support for l -asparaginase loading as well as its usage in future industrial applications.

π-Conjugated two-dimensional covalent organic frameworks (COFs) represent a family of rising oxygen electrocatalysts due to their controllable architectures, outstanding electrical conductivity and highly exposed molecular active sites. Herein, we report a novel ladder type π-conjugated two-dimensional benzoimidazobenzophenanthroline-linked iron-phthalocyanine COF (denoted as FePc-BBL COF) via solvothermal synthesis between 2,3,9,10,16,17,23,24-octacarboxyphthalocyaninato iron (Fe-OCAP) and 1,2,4,5-tetramino-benzoquinone (TABQ). Due to the robust fused aromatic backbone, the porous framework structure, and the natural Fe-N4 high active sites, the newly developed FePc-BBL COF exhibits unusual oxygen reduction reaction (ORR) activities and fast kinetics with a remarkable half-wave potential of 0.933 V and an ultralow Tafel slope of 24.8 mV dec-1 in alkaline media. In addition, the FePc-BBL COF also exhibits an ultrahigh turnover frequency (TOF) of 78.1 e- site-1 s-1 at 0.85 V vs. RHE and mass activity of 26.5 A mgFe-1, represents 16.4- and 57.2-fold enhancements compare to Pt/C. Furthermore, when employed as a cathode electrocatalyst for zinc-air batteries, FePc-BBL COF delivered superior maximum power density (181.4 mW cm-2), specific capacity (773 mAh g-1), and long-term durability compared with Pt/C as air electrodes. This work provided a promising strategy in engineering reticular materials to design highly stable and efficient pyrolysis-free electrocatalyst for practical value sustainable energy conversion and storage devices.

Covalent organic frameworks (COFs) are a new type of visible-light-driven photocatalysts, while effectively improving the separation and transfer of light-induced charges is of the key point to further enhance their activity. In this work, a new COF-based core–shell Z-scheme heterojunction WO3@TpPa-1-COF was firstly synthesized by in-situ etching bulk WO3 into ultra-small nanostructure. Further, a ternary WO3@TpPa-1-COF/rGO composite with rGO attached on the surface of TpPa-1-COF was prepared by a facile one-pot photoreduction of GO solution containing as-synthesized WO3@TpPa-1-COF. The results of photocatalytic measurements show that the WO3@TpPa-1-COF/rGO(30%) composite material possesses a hydrogen evolution rate of 26.73 mmol·g−1·h−1 under visible-light irradiation, which is 11.73 and 1.6 times higher than that of TpPa-1-COF and WO3@TpPa-1-COF, respectively. Further study demonstrate a Z-Scheme charge transfer pathway exists in WO3@TpPa-1-COF/rGO composite which promote the separation of photogenerated charge carriers from COF, while the rGO attached on COF serves as electron collector in photocatalytic process further facilitating the transfer of photogenerated electrons to active sites. The reported strategy of building core–shell COF-base heterostructure and the resulting architecture with rGO as electron collector in Z-Scheme for facilitating the separation and transfer of charge carriers may open a new way for the design of highly efficient photocatalysts.

Covalent organic polymer has been considered as the promising organic semiconductor for the photocatalytic CO2 reduction reaction (CO2RR) due to its unique features such as adjustable framework, durable stability and feasible bandgap energy, et al. Herein, we reports a novel CoII-porphyrin/RuII-pincer complex coupled polymer (CoPor-RuN3), which exhibits efficient visible light-responsive CO2RR activity with the average CO/CH4 yields of 37.1/1.57 μmol g-1 h-1 and a total photoactivity of 86.8 μmol g-1 h-1, 25.5 and 4.5 times that of the CoPor and RuN3 monomers, respectively. It is found that the two metal centers (Co/Ru) and the conjugated framework of the polymer are essential for efficient CO2RR. A series of in-situ characterizations prove that periodic Z-scheme molecular junctions are formed by the linkage of amide group in the CoPor-RuN3 polymer to facilitatie the photogenerated electron transfer from CoPor units to RuN3 ones, in which Ru and Co serve as the reduction and oxidative single-atom sites, respectively. Moreover, the wavelet transform plots of X-ray absorption spectra of Ru K-edge shows that two CH3CN ligands are easily dissociated from the Ru center during the photocatalytic process, leaving empty sites for the adsorption of CO2. Based on the experimental observations and theoretical calculations, a plausible photocatalytic CO2 reduction mechanism involving a pincer-typed N′NN′-Ru-CO intermediate (N′NN′ = 2,6-bis(benzimidazol-2-yl)pyridine) as the real reduction center is clarified. This work gives a new thread for exploring broadband-responsive covalent organic polymers with uniformly dispersed single-atom catalytic sites for CO2 photoreduction.

Adaptive membranes that can intelligently control their permeability or selectivity depending on the surrounding environments are of extraordinary importance in the separation technology area. Herein, we report the pH responsive membranes through covalently grafting weak Polyelectrolytes (poly(acrylic acid) (PAA) or poly(4-vinylpyridine) (P4VP)) onto the regular two dimensional (2D) channels stacked by Graphene oxide (GO) nanosheets. Attributed to the reversible shrinking/stretching function of PAA (or P4VP) chains with the variation of external pH, the switchable 2D GO channels are thus established successfully. Correspondingly, the resulting PAA@GO and P4VP@GO 2D membranes show promising nano-gating ratios of ∼ 5 accompanied by satisfactory water permeances. Furthermore, the pH responsive 2D channels render these two types of membranes with the adaptive ability of rejecting different sized species according to separation requirements. For disposing industrial alkaline (or acid) effluents, PAA@GO (or P4VP@GO) membranes exhibit outstanding alkaline (or acid) recovery performance as well.

Cost-efficient, potassium–organic batteries with high stability are a high-profile technology for grid-scale energy storage. However, their development has been limited by the lack of stable cathode materials, which must be cost-effective without compromising performance. Here we present a commercially available organic cathode (BR-rGO) constructed by utilizing covalent bonding and intercalation strategies toward high energy density potassium storage. In our design, covalent bonds between BR and rGO effectively stabilize the structure of the electrode, thereby limiting the dissolution of organic materials in the electrolyte. Furthermore, intercalation of organic molecules into rGO layers provides more accessible active sites and K+/electron diffusion channels, leading to enhanced reaction kinetics. The resulting cathode delivered an excellent specific capacity of 127 mAh g−1 after 150 cycles at 0.2 A g−1 and superior rate capability. Upon incorporating the BR-rGO cathode into a full battery with a porous carbon anode, the cathode exhibited a high energy density of 168 Wh kg−1 and a superior cycle stability over 3000 cycles. Attaining high energy density using commercially available components is an achievement that represents an essential step towards practical potassium-ion full batteries.

Simultaneously modulating the adsorption and electronic properties of pure conjugated polymers for efficient photosensitized oxidation of organics is environmentally desirable but still challenging. Of interest to us in this work was to construct artificial defective donor-sensitizer-acceptor covalent triazine framework (CTF) and probe how the transformation of barely active pure polymers into high-efficiency photosensitizer occurred. The thiophene/cyano (-Th/-CN) donor–acceptor (D–A) configurations in the structural terminations were facilely formed by incorporating thiophene units into CTF (denoted as CTF-xTh), which simultaneously induced plenty of defect sites spread over the polymer networks. Experimental and theoretical studies revealed that the incorporated D–A dyads could serve as charge delivery channels for intramolecular charge transfer transition and render the photogenerated charges spatially delocalized at the -Th/-CN terminated edge sites, which impels the proceeding of photoactivation reaction with oxyanions (represented by HSO5−). Moreover, the edge defects could serve as high-energy adsorption sites for enriching organics (represented by bisphenol-A (BPA)), which enables the generated reactive species to be in close proximity to contaminants to have greater chances of attacking these molecules. With these merits, a 4-fold enhancement of HSO5− conversion and a 10-fold improvement of BPA adsorption were found in Vis/ HSO5−/CTF-5Th system as compared with corresponding pristine CTF system, and thus the overall BPA removal increased by 8 times. This work demonstrated the first instance of using D-A tailored CTF for photosensitized oxidation of organics and provided new opportunities toward designing of novel polymers for visible-light-driven photocatalysis.

To overcome the loss of soluble lithium polysulfides (LiPSs) generated during the discharge process of lithium-sulfur (Li-S) batteries, a lot of efforts have been devoted to the design of novel micro- or nano-structured host materials, aiming to trap soluble polysulfide within the network. Covalent organic framework (COF) as porous materials have been receiving a great deal of attention. Herein, an allyl-rich triazine covalent organic framework (ART-COF) synthesized by 5-(allyloxy) isophthalaldehyde and 4,4′,4″-(1,3,5-triazine-2,4,6-triyl) trianiline (TAPT) is used as cathode host material for Li-S batteries. Owning to the synergistic effect of physical force (through microporous channel) and chemical force (through C-S covalent bond and dipole–dipole interaction between nitrogen and lithium), the shuttle action of LiPSs to anode electrode can be effectively limited. ART-COF shows a high initial specific capacity of 1270 mAh g−1 which retains 1220 mAh g−1 after 100 charge–discharge cycles at 0.2C, and even at 1C it also demonstrates an initial specific capacity of 993 mAh g−1 which retains 818 mAh g−1 after 500 cycles with a low fading rate of 0.035% per cycle. This work represents a sustainable approach for developing highly stable and long-lived Li-S batteries.

Currently, the multilayer architecture is recognized as one of shining stars with exciting applications in environment and catalysis, energy storage/conversion, optoelectronics and so forth. However, different to the typical MXenes, the fabrication of layered transition metal oxides is still a grand challenge, since they are highly difficult to be exfoliated into multilayered structures, owing to their intrinsically strong covalent bond. Here, we report the controlled growth of MXenes-like WO3 architecture in the families of transition metal oxides with perfectly multilayered features, by tailoring the formation of precursor WO3·H2O based on the competition between the concentrations of WO42− and anions (NO3–, Cl−) within the solution. The as-built multilayer WO3 architecture has overall superior physical performance to conventional solid counterparts, and exhibits a remarkable photocurrent density of 2.3 mA cm−2 at 1.23 vs. RHE under AM 1.5G illumination, which is the highest one among those of WO3 photoanodes without cocatalysts/dopants in neutral solution ever reported.

Visible light driven peroxymonosulfate (PMS) activation by metal-free photocatalysts has attracted great attention. In present study, covalent organic frameworks (COF-PRD, PRD refers to pyridine) were synthesized and utilized to activate PMS to degrade bisphenol A (BPA) with visible light (VL) irradiation. COF-PRD with PMS improved 3.5 times degradation kinetics for BPA degradation relative to that of COF-PRD without PMS with VL irradiation. ·O2–, h+ and 1O2 dominated the BPA degradation in COF-PRD with PMS with VL irradiation. Under anaerobic condition, BPA could still be effectively degraded due to the reaction of PMS with e– to generate ·SO4–. In addition to BPA, bisphenol F (BPF), bisphenol B (BPB), bisphenol Z (BPZ) and bisphenol AP (BPAP) could also be effectively degraded by COF-PRD with PMS under VL irradiation conditions. Density functional theory (DFT) calculation together with intermediates determination showed that the main degradation pathway of bisphenols (BPs) included hydroxylation, electrophilic attack and ring-opening reaction. The bioaccumulation effects of BPs were greatly reduced during the degradation process. Moreover, COF-PRD exhibited excellent reusability in ten successive cycles. Clearly, COF-PRD could be employed as photocatalytic PMS activation to degrade bisphenols under both aerobic and anaerobic conditions.

Covalent organic frameworks (COFs), a series of crystalline materials with ordered nanopores, are highly desirable for ultrafast and selective nanofiltration. However, COF-based membranes are typically synthesized via difficult synthetic procedures with long reaction time and show poor mechanical properties, which may hinder their widespread applications. Herein, a facile interfacial method is developed to synthesize COF membranes via the synergistic effect of interfacial diffusion and in-phase Brownian motion. Continuous free-standing COF films with a thickness of 111 nm are obtained within only 3 h under mild reaction conditions. Meanwhile, this synthesis method is suitable for the fabrication of COF membranes with a thin-film-composite (TFC) structure, enabling obtained COF membranes good mechanical properties under external forces and practical nanofiltration tests. Compared with other reported nanofiltration membranes, TFC-COFs exhibit state-of-the-art water permeance (173.94 L m2 h−1 bar−1) and superior rejections exceeding 98.50% to dyes larger than 1.3 nm. Precisely selective sieving of obtained TFC-COFs is systematically studied by separating diverse mixed dye solutions. Furthermore, monomers used in this method can be replaced, creating COF-based membranes with customizable functionality to enable a broad range of selective separations.

Mixed-matrix membranes containing covalent-organic frameworks (COFs) and polymer phase hold great promise for effective and economical CO2 separation due to the robust and tunable porous framework structures of COFs. However, the pore sizes of most reported COFs are larger than gas molecules. Meanwhile, the undesired COF aggregation impedes the preparation of continuous and defect-free membranes. Herein, we describe a new strategy for the facile manufacture of 2D-COF based mixed-matrix membranes via in situ “bottom-up” growth approach which involved the admixing of COF precursors with PEO monomers at the molecular level in a solvent-free system. Free radical polymerization allowed the formation of polymer membranes containing well-dispersed COF precursors. The 2D-COFs with uniform distributions were further generated via the covalent linkages of precursors within the cross-linked polymer network under microwave assisted Zincke reaction. The resulting mixed-matrix membrane exhibited a remarkable permeability of 803.9 barrer for CO2 and selectivities of 61.4, 19.8, 15.0 for CO2/N2, CO2/CH4, CO2/H2, respectively, exceeding the known upper-bound limits reported for polymer membranes. Meanwhile, the membranes displayed a one-month stability confirming its exceptional long-term operational stability and great potential for industrial gas separations.

Covalent triazine frameworks (CTFs) are drawing substantial interest as porous crystalline two-dimensional (2D) or three-dimensional (3D) nanomaterials. Fabrication of CTFs nanoribbon is challenging but appealing to separation and photocatalysis. Here we for the first time report the synthesis of crystalline CTF-1 nanoribbons (CTF-1-NR) comprising 2–3 covalent triazine framework units in width through a polar solvent-induced fragmentation strategy. The width of 1D nanoribbons can be facilely tuned by varying the solvent (e.g. ethanol) volume in trifluoromethanesulfonic acid layer after trimerization of aromatic nitriles. The CTF-1-NR are intercalated with Graphene oxide (GO) membranes to extend 1H NMR transverse relaxation time (T2) and enlarge the confined interspacing (∼8.8 A), providing ultrafast water transport (∼60 L m-2h−1 bar−1) and high dye molecules rejection (98%). More significantly, the bridging CTF-1-NR enhances charge-carrier separation and gains superior solar-cleaning recoverable permeability (∼7 folds higher than GO). This study provides novel insight into the synthesis of crystalline COF nanoribbons and membrane separation.

Covalent organic frameworks (COFs), have been used as potential photocatalysts for the degradation of antibiotics, but their poor recyclability limits the application in practical environment. In this paper, a novel melamine sponge@COF composite sponge was successfully prepared via a one-pot method by “reactive seeding” strategy. Such strategy enables the uniform and sturdy growth of small-sized COF-TpTt on the melamine sponge (MS) fibers. The composite sponge (MS@TpTt) effectively overcomes the difficulty of recycling for the powder character of general COFs, and shows excellent photocatalytic activity towards the degradation of tetracycline antibiotics under visible light. The finding in this work provides a simple strategy for the preparation of COF-based composite monolithic materials with high degradation performance, easy circulation and high stability for desired catalytic applications.

Covalent triazine frameworks (CTFs) are appealing photocatalysts for environmental remediation. However, high recombination rate of photogenerated electrons and holes is the key limitation for its application. Notably, peroxydisulfate (PDS) can potentially act as electron withdrawing center to efficiently prevent the recombination. Herein, the photocatalysis of CTF under visible light (VL) coupled with PDS shows great potential for pollutants removal, taking carbamazepine (CBZ) as a case, in which the observed rate constant of CBZ degradation in VL/CTF/PDS process is 9.0 and 4.5 times to that in CTF/PDS and VL/CTF processes, respectively. PDS can construct a bridge to enhance the charge separation and transfer efficiency of CTF to prevent the recombination of electrons and holes, thus significantly improving the oxidation ability of the VL/CTF/PDS process. Moreover, the accepted electrons can initiate the PDS activation to generate more reactive species, thus contributing to higher oxidation capacity of the VL/CTF/PDS process. Furthermore, the VL/CTF/PDS process tends to attack the 1 N and 12C–15C atoms of CBZ to induce the cleavage of N-C bond and oxidation of C C bond, thus decomposing CBZ into lower molecules and finally being mineralized. This study will promote the development on applying photocatalysis of CTF materials and PDS activation in practical environmental remediation.

Diffusion dialysis (DD) based on the anion exchange membranes (AEMs) is considered as a promising technology for acid recovery. Two-dimensional (2D) cationic covalent organic frameworks (COF) with uniform pores and intrinsic cationic-type skeleton structures are excellent candidates for the synthesis of the AEMs. However, the sustaining of crystallinity and porosity in acid environments is still a key challenge for the existing COF, which severely restricts their applicability in the acid recovery. Herein, by introducing OH functionalities adjacent to the Schiff base centers, we synthesized the acid-stable cationic COF (DhaTGCl) layers with intralayer hydrogen bond on the surface of hydrolytic polyacrylonitrile (HPAN) ultrafiltration membrane. The strong electrostatic repulsion, endowed by cationic guanidine-based knots, as well as well-aligned proton channel, constructed by OH functionalities, rendered extremely high separation factor (S) of 4589 ± 684.2 for HCl recovery from HCl/FeCl2 solution. The membrane maintained high selectivity toward H+/Fe2+ after 10 cycles during DD process, while the one without OH degraded during cycling experiments. Our results imply that building the intralayer H-bonding interactions could be a promising approach for expanding the application of the COF membranes for acid recovery.

The selective adsorption of ethane (C2H6) in the separation process of C2H6 and ethylene (C2H4) is of great importance for obtaining polymer-grade C2H4 in industry, yet it is still challenging task to develop suitable adsorbents with large adsorption capacity, high selectivity and excellent stability for efficient separation of C2H6/C2H4. Herein, carbazole-based covalent trazine frameworks (CTFs) prepared by ionothermal strategy are proposed for C2H6/C2H4 for the first time. By changing the preparation conditions, the obtained CTF-DCTC-500 shows defective ultramicropore structure while CTF-DCTC-400 does not. Compared with CTF-DCTC-400, the introduction of defective ultramicropore in CTF-DCTC-500 not only increases the adsorption capacity of C2H6, but also exhibits obviously C2H6/C2H4 separation behavior. Surprisingly, the adsorption selectivity of C2H6/C2H4 in CTF-DCTC-500 at 298 K and 1 bar is up to 2.08, exceeding all reported COF materials. To the best of our knowledge, this is first reported CTF material with preferential C2H6 adsorption over C2H4. Breakthrough experiments on CTF-DCTC-500 reveal that the polymer-grade C2H4 with 99.95 % purity can be directly obtained from the C2H6/C2H4 mixture in the practical application. Furthermore, CTF-DCTC-500 possesses the high chemical stability and excellent cycling stability and regeneration for C2H6/C2H4 separation, indicating it is a promising material for C2H6/C2H4 separation. This work not only provides a highly stable carbazole-based CTF with high C2H6/C2H4 separation selectivity, but also emphasizes the important role of defective ultramicropore structure on C2H6/C2H4 separation.

Achieving maximum atom-utilization efficiency is desirable to facilitate the charge separation and CO2 activation for photocatalytic CO2 reduction. Herein, we report a well-defined positioned synthesis of Pt single atoms in ethylene glycol (EG)-modified covalent triazine framework (Pt-SA/CTF-1) via a photo-deposition method for efficient photoreduction CO2 to CH4 under visible light irradiation. The well-defined coordination structure of Pt–N(C) sites in the Pt-SA/CTF-1 catalyst has been probed by HAADF-STEM and EXAFS. Results show that Pt single atoms confined into CTF-1 not only improved CO2 adsorption and activation but also accelerated the separation and transfer of photogenerated carriers in CTF-1. Consequently, Pt-SA/CTF-1 exhibited superior photoactivity and stability, which significantly surpass the Pt nanoparticles-based CTF-1, affording CH4 as the main reduction product. This work showcases an operable avenue to develop single-metal-atom photocatalysts and a mechanistic insight into photoreduction of CO2 by CTF-based composite.

Plant-derived renewable and biodegradable bioplastics are attractive alternatives to petroleum-based materials, but their applicability is limited by insufficient interface bonding and the antibacterial properties of biopolymer. Inspired by the unique hierarchical structure of nacre, we report a facile and sustainable mineral–organic strategy that fabricates a soy protein (SP)-based film with excellent mechanical strength and toughness. The nitrogen-coordinating boronic diester (NB) is synthesized from boronic acid and diols, which form enhanced cross-linking networks through dynamic glue linkages. As a glue molecule, caffeic acid (CA) containing phenolic compounds can co-assemble with hydroxyapatite (HA) in the SP matrix to produce inorganic–organic CA-functionalized HA (CHA) hybrids. The strong affinity between the NB and CHA hybrids combined with dynamic covalent bonds and sacrificial hydrogen bonds substantially improves the bonding strength and cohesion of the SP-based composites. The tensile strength and toughness of the resultant film were 13.89 MPa and 14.72 MJ/m3, respectively, 361% and 489% higher than the pristine SP film. Owing to the biomineralization and phenolic components, the incorporated NB@CHA hybrids endow the film with desirable water resistance, flame retardancy, UV protection performance, and antibacterial activity. This biomimetic strategy provides a novel and versatile fabrication route to high-performance SP-based bioplastics for engineering and biological applications.

ZnxCd1-xS is a prospective photocatalyst with wide visible-light absorption up to 500 nm, but its stability and activity are still facing huge challenges. Herein, L-Cysteine capped Mo2C (L-Mo2C) nanoplates were used to anchor Zn2+/Cd2+ to in-situ grow Zn0.67Cd0.33S nanomaterial for constructing a highly efficient and robust L-Mo2C/Zn0.67Cd0.33S heterojunction through intimate Mo-S covalent bonds for photocatalytic hydrogen evolution reaction (HER). This work not only suppresses the photo-corrosion of Zn0.67Cd0.33S nanomaterial by the construction of strong L-Mo2C/Zn0.67Cd0.33S Schottky heterojunction but also greatly improves the charge transfer efficiency by generating a strong internal electric field. As a result, the optimized L-Mo2C/Zn0.67Cd0.33S-5 heterojunction exhibits an enhanced HER rate of 34.66 mmol h−1 g−1 without an obvious decrease for continuous 24 h under visible irradiation, which is 4.8 times and 1.23 times than that of pristine Zn0.67Cd0.33S and uncapped Mo2C/Zn0.67Cd0.33S-5. This research highlights the role of Mo2C in photocatalytic HER, which provides a novel method to suppress the photo-corrosion of Zn0.67Cd0.33S-based composite.

Halogenated activated carbon adsorbents exhibit superior mercury capture performance in the flue gas. Not only the fabrication of effective adsorbents, but the used adsorbents stability is also crucial. It is essentially determined by product bonding nature. Here, Density functional theory was employed to investigate spent halogenated activated carbon adsorbents bonding nature at the atomic level. Seven possible mercury-containing product molecular geometries and effects of halogen species (X = Cl/Br/I) were considered. Specifically, bond length value, and bond order of Hg-C, Hg-X and C-X bonds of interest were calculated to investigate product stability in the gaseous phase. It was found that mercury was attached on the carbonaceous surface with C-Hg Mayer bond order around 0.5 in product structures G and H, suggesting a weak interaction. In other possible product molecular geometries, C-Hg or X-Hg exhibited a single bond character. Moreover, effects of halogen atoms on X-Hg and C-X bond strength were discussed. Electron localization function (ELF) and Localized orbital locator (LOL) were utilized to determine electron high localization regions. Results indicated C-Hg and C-X on the carbonaceous surface are covalent bonds and formed X-Hg bonds are ionic bonds. Furthermore, atom composition in the localized molecular orbital was calculated via the Hirshfeld method. In summary, this study investigated the bonding nature of used halogenated activated carbon adsorbents. The results are beneficial for fabricating more environmental-friendly mercury removal adsorbents in the future.

Here, we present a two-step continuous flow enzymatic synthesis process in monolithic microreactors using basic sugars as substrates. In the first step UDP-glucose pyrophosphorylase (TaGalU) catalyses the synthesis of uridine-diphosphate-glucose (UDP-Glc) using uridine triphosphate (UTP) and glucose-1-phosphate (Glc-1-P). This is followed by the trehalose transferase (mCherry-TuTreT) catalysed reaction of UDP-Glc and Glc, to obtain trehalose. First, procedures for immobilisation of both enzymes on functionalised silica supports were studied and it was found that covalent bonding by amino groups using a glutaraldehyde linker gives highly active biocatalysts. Due to a drastic difference in temperature range of activity and stability of the immobilised enzymes a bi-reactor cascade was rationally the best solution. Depending on the applied flow rate and hence reaction (residence) time (1.5–10 min) the space-time-yield values varied, respectively, from 1.9 to 14.4 and 8.3 to 49.6 gproduct·L-1·h−1·mgprotein-1, for UDP-glucose pyrophosphorylase and trehalose transferase catalysed reactions. Prolonged (100 h) continuous flow operation showed that the system is operationally stable, but owing to neutral pH, it is prone to microbiological infections. They can be eliminated applying an antibacterial/antifungal therapy or preventive actions by storing and washing the reactors with a NaN3 solution. The presented process paves the way for the continuous in flow synthesis of natural and non-natural trehalose analogues and disaccharides.

Fabrication of covalent adaptable networks with the combination of intrinsic photothermal responsiveness, NIR-triggered welding, multiple-shape memory, and selective shape memory recovery remains a challenge. Herein, we developed a series of poly(urea-oxime urethane) thermosets (PUOUs) based on 1,4-benzoquinone dioxime, Jeffamine D230, and hexamethylene diisocyanate trimer using an organic bismuth compound (U600) as the catalyst. The inherently strong photothermal effect of the PUOUs could trigger and manipulate the dynamic exchange of oxime-carbamate bonds to undergo rapid welding by near-infrared laser (NIR, λ = 808 nm) irradiation. The lap shear strength of the two PUOUs with an overlapped area of 4 cm × 4 cm reached 1.2 MPa after irradiation by a NIR laser for 150 s with an irradiation intensity of 2.7 W/cm2. Due to the two independent glass transition temperatures of the PUOUs, triple shape memory property was detected and selective shape memory recovery could achieve in the area subjected to NIR irradiation. Hence, the PUOUs show vast potential for the construction of weldable thermosets and may find applications in intelligent shape-memory devices.

An environmentally friendly water-based NP-GLIDE polyurethane (PU) coating has been developed. The term NP-GLIDE as described herein suggests that water, organic solvents, or contaminants in these liquids have no problem to glide down the coating or that the coating bears nano-pools of a grafted lubricating ingredient for dewetting enablement. To prepare a coating, a blocked polyisocyanate and a graft copolymer polyol-g-PDMS consisting of a water-dispersible polyol backbone and poly(dimethyl siloxane) (PDMS) side-chains were co-dispersed in water containing 5.0 vol.% of dipropylene glycol monomethyl ether, cast onto a substrate to evaporate the solvent, and then thermally cured. As the liquid-like PDMS is covalently bound to the polyol backbone, it could not undergo macrophase separation and instead formed nano-pools with diameters of less than 30 nm throughout the polyurethane matrix. Meanwhile, the surface of the coating changed from solid-like to liquid-like due to the surface enrichment by PDMS. Of the three families of polyol-g-PDMS samples that were synthesized and evaluated, only one of these polyol-g-PDMS families yielded NP-GLIDE coatings with superior properties. All of the test liquids with surface tensions above 23 mN/m readily and cleanly slid down the optimized coatings that had a hardness of 3H. Moreover, both marker ink and a commercial paint contracted on these coatings and the contracted ink could be readily and cleanly removed with tissue paper without leaving any traces behind. Moreover, the ink contraction capability was maintained after the writing and erasing test had been performed for more than 30 cycles. The environmental friendliness of the coating formation process and the superior anti-smudge performance of the resultant coatings suggested that they have excellent potential for practical applications.

In this work, a multifunctional coating with excellent anti-fog, self-cleaning, and antibacterial properties was developed by grafting poly(N-vinylpyrrolidone-co-maleic anhydride) (poly(NVP-co-MA)) co-polymer on glass slides. The highly hydrophilic PVP segments can render the coating excellent anti-fog and self-cleaning properties because they can lead water droplets to spread uniformly on the surface, while the PMA segments can form robust covalent bonds with the amino-group on the substrate to enhance the durability of the coating. In addition, the coating also displayed outstanding ability to resist microorganism adhesion due to the highly hydrophilic PVP segments. These merits prove that the multifunctional coating developed in this work can be widely used in many applications where anti-fog, self-cleaning, and antimicrobial adhesion properties are needed.

The aim of this study was to deliver ribonuclease A (RNase A) intracellularly using dextran nanogels for cancer treatment. To this end, positively charged RNase A was electrostatically loaded in anionic dextran nanogels with an average size of 205 nm, which were prepared by an inverse mini-emulsion technique. To chemically immobilize the loaded protein in the nanogels and prevent its unwanted release in the extracellular environment, the protein was covalently linked to the nanogel network via disulfide bonds, which are cleavable in the reductive cytosolic environment. A high loading efficiency and loading content of RNase A (75% and 20%, respectively) were obtained. Coating of the nanogels with the cationic polymer polyethyleneimine reversed the zeta potential of nanogels from −31.6 mV to +7.6 mV. The nanogels showed a fast and triggered release of RNase in the presence of glutathione. Negatively charged RNase A loaded nanogels did not show cytotoxicity, likely due to their limited cellular uptake. In contrast, PEI coated RNase A loaded nanogels showed high uptake by MDA-MB 231 breast cancer cells and exhibited a concentration-dependent cytotoxic effect by apoptosis. The results demonstrate that PEI coated nanogels are promising nano-carriers for intracellular protein delivery, encouraging further evaluation of this formulation in preclinical models.

A kind of novel hybrid membrane for the detection and separation of mercury ion (Hg2+) was fabricated by filtrating gold nanocluster embedded bovine serum albumin (AuNCs@BSA) nanofibers and graphene oxide (GO). With the help of N-ethyl-N′-(3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide, the BSA nanofiber and graphene oxide (GO) can be covalently binded due to the reaction between amino and carboxyl groups. The separation mechanism of the hybrid membrane are attributed to the high-affinity metallophilic Hg2+-Au+ interactions, Hg2+-cysteine residue binding as well as electrostatic interaction. The experimental results indicated that the created GO-AuNCs@BSA hybrid membrane exhibits excellent performance for removing Hg2+ pollutants from water. The adsorbing efficiency of Hg2+ can reach up to 90.45% at the first cycle and the separation process can be repeated numerous times without damaging the membrane structure.

Immobilization of enzymes on nanofibrous membranes could offer easy recycling and feasible continuous operations. In this study, a novel terpolymer poly (glycidyl methacrylate-co-methylacrylate)-g-polyethylene oxide (P(GMA-co-MA)-g-PEO) containing reactive epoxy groups and hydrophilic polyethylene oxide branch chain was synthesized. Electrospun P(GMA-co-MA)-g-PEO nanofibrous membrane was used for the immobilization of lipase molecules by covalent binding with the epoxy groups. The influences of the enzyme loading and activity by nanofibrous membranes with different content of monomers and immobilization temperature were investigated. The immobilized lipase achieved high enzyme loading of 150 mg/g and the maximum activity of 0.673 U/mg under the optimum immobilization conditions. The hydrophilic PEO branch chain was beneficial for the stabilization of the enzyme conformation which would promote the improvement of enzyme activity and stability. The results of FTIR spectra and SEM images of nanofibrous membranes before and after immobilization demonstrated that lipase has been successfully covalently immobilized on the nanofibrous membranes. The optimal pH and temperature were 7.0 and 35 °C for catalysis reaction of the immobilized lipase. The stabilities of the immobilized lipase were also investigated. The results demonstrated that the immobilized lipase has good thermal stability, reusability and organic solvent stability. The good stabilities of immobilized lipase revealed that P(GMA-co-MA)-g-PEO nanofibrous membrane is an excellent carrier for enzyme immobilization.

A facile strategy to immobilize cellulase was developed in this work. Firstly, crosslinked styrene and maleic anhydride copolymer nanoparticles (SMN) were conveniently synthesized as carrier by self-stable precipitation polymerization in the absence of any stabilizer. Benefit from the high reactivity of anhydride groups, the cellulase was then covalently bound to SMN at mild condition. The optimum loading amount of cellulase on SMN was determined to be 167 mg/g. Although the immobilized cellulase showed almost no change of activity at temperature from 30 °C to 80 °C compared to free cellulase, its pH stability was significantly improved. After immobilization, the optimum pH shifted to 5.0 and immobilized cellulase could retain 80% activity at pH 8.0, which was much higher than that of free enzyme (14%). Furthermore, the immobilized cellulase showed excellent reusability in catalytic hydrolysis of carboxymethylcellulose sodium salt, preserving almost 100% activity after recycling 6 times and loss only 20% activity after 10 cycles. The results suggest that SMN is a promising carrier for enzyme immobilization.

Low temperature applicable cyclic sulfonium functionalized poly(vinylbenzyl chloride) (PVBC) electrolyte gelator for partially hydrolyzed poly(acrylamide) (HPAM) in situ gel is described herein. Addition of polyelectrolyte gelator to HPAM generated covalently crosslinked in situ gels through formation of ester crosslinks under reservoir conditions. The generation of covalent crosslinks through chemically nucleophilic attack by carboxylate groups tethered to HPAM backbone to sulfonium moieties was demonstrated by corresponding spectra analysis of nuclear magnetic resonance (NMR) and rheological studies. Compared to high temperature phenol/formaldehyde and poly(ethyleneimine) gelator system, the gelation of PVBCTHt polyelectrolyte gelator and HPAM occurred over a broad range of temperatures from 25 to 80 °C. At 25 °C the gelation of PVBCTHt gelator and HPAM was significantly delayed to weeks compared to Cr3+-HPAM system having fast gelation kinetics in 6 h. Due to its delayed gel formation over weeks at room temperature, the gel could be deployed for in-depth reservoir treatment. The gelant showed excellent salt and pH resistance under reservoir conditions as reflected by mechanical integrity of in situ bulk gel. Core flooding experiment on sandpack demonstrated the gel could efficiently divert brine flow for conformance control, which displayed better plugging efficiency than Cr3+-HPAM system.

3-Pentadecafluoroheptyl,5-perfluorophenyl-1,2,4-oxadiazole (FOX) molecules were attached onto a graphene oxide (GO) via a facile aromatic substitution in alkaline environment. This approach allows achieving high degree of functionalization under mild conditions. The covalent attachment of perfluoromoieties onto GO lamellae was confirmed by spectroscopic analyses. The performance of these nanoplatforms (GOF) as oxygen reservoirs was assessed at different concentrations and temperature. The results revealed that under physiologic conditions GO and FOX synergistically operate for increasing oxygen uptake and release, either from a thermodynamic and a kinetic point of view. Even at low concentrations, GOF showed values in terms of oxygen content at saturation and diffusion rate higher than those of other materials currently proposed as O2-reservoirs in tissue engineering, for cell oxygenation during the regeneration of vascularized tissues. Furthermore, GOF displayed a high cytocompatibility. These findings open new, intriguing scenarios for a further application field of graphene-derived materials.

In this study, a novel 4,4′-diaminostilbene-2,2′-disulfonic acid (DASDSA)-functionalized reduced graphene oxide (DASDSA-rGO) was prepared via simple refluxing method involving GO and DASDSA in the presence of ammonia solution followed by reduction with hydrazine hydrate. FTIR spectroscopy, Raman scattering, X-ray photoelectron spectroscopy (XPS), and XRD analyses confirmed the successful functionalization and reduction of GO in DASDSA-rGO. The FTIR and XPS analyses also confirmed covalent bond formation between DASDSA and graphene. The DASDSA spacer successfully minimized the restacking of rGO sheets as observed from FESEM analysis. Several redox transition states and SO 3 H groups of grafted DASDSA moieties provided excellent pseudocapacitance performance of the DASDSA-rGO electrode. The DASDSA-rGO electrode showed high specific capacitance ( C ) value of 1042 F g −1 at a current density of 1 A g −1 , good cycling stability (95% capacitance retention after 3000 cycles), and excellent rate capability in a three-electrode setup. The DASDSA-rGO (positive electrode) and rGO (negative electrode) were assembled to prepare an asymmetric supercapacitor (ASC) device. The power density values of the ASC device were calculated to be 650 and 7800 W kg −1 at energy density values of 37.37 and 23.78 W h kg −1 , respectively. The ASC device exhibited C value of 159 F g −1 at 1 A g −1 and displayed 86% retention in C after 8500 cycles. The EIS data of the three-electrode system and ASC device were fitted with Z-views to determine the different resistance components after a different number of charge–discharge cycles in a cycling stability test.

The cyclotetrapolymerization of four diallylamine salt monomers, containing chelating motifs of aminocarboxylate, aminophosphonate, aminosulfonate and primary amine at the terminal of an alkyl chain (CH2)12, has led to the synthesis of a tetrapolymer in excellent yield. A copolymer of methacrylate having acetyl acetate pendant has also been synthesized. The two polymers in aqueous solution is found to form gel because of covalent crosslinking via formation of imine bond by condensation of –NH2 groups of the tetrapolymer with the acetoacetate groups of the polymethacrylate copolymer. This is the first example of a cyclopolymer immobilized by covalent crosslinking with a polymethacrylate. The hydrogel, embedded with chelating motifs of aminoalkyl-carboxylate, phosphonate and sulfonate as well as imine motifs, demonstrated remarkable efficacies for the removal of Hg(II) ions at ppb levels. A 50 mg-dose of the hydrogel immersed in aqueous medium (20 mL) could reduce the concentration of Hg(II) from 200 and 500 ppb to 0.20 and 0.17 ppb, respectively, within 30 min. The hydrogel has also been shown to be remarkably effective in the removal of several toxic and priority metal pollutants from the matrix of an industrial wastewater.

A microreactor with a square shaped reactor chamber was developed with the aim to correlate enzyme positioning with biocatalytic activity. The enzyme position as an important parameter to improve the contribution of the individual enzymes towards the overall reactor efficacy was therefore evaluated experimentally and by computational fluid dynamics (CFD) simulations. Ultimately, such a correlation would lead to faster development through computational pre-screening and optimized experimental design. In this proof-of-concept study, microreactors were prepared in a 2-step curing process of an off-stoichiometric thiol-ene-epoxy (OSTE+) mixture employing both a thiol-ene (TEC) and a thiol-epoxy curing reaction. Subsequent surface functionalization of the remaining thiol groups on the reactor surface through stenciled photoinitiated TEC enabled the preparation of specific surface patterns in the reactor. Patterns were visualized using an allyl-functional disperse red dye, illustrating the successful preparation of a fully reacted surface, a half covered surface and 2 checkerboard patterns. Similarly, allyl glycidyl ether was exploited to functionalize the microreactor surface with epoxide groups, which were used for covalent immobilization of horseradish peroxidase (HRP) in the same patterns. Biocatalytic activity measurements confirmed a clear dependency of the overall reactor performance depending on the spatial distribution of the immobilized enzymes, where specifically the two checkerboard motifs were identified as being particularly effective compared to enzymes covering homogeneously the entire reactor surface. The performance of the same configurations was additionally determined by 3-dimensional CFD simulations. The computational model predicted the same tendencies for the overall reactor performance as obtained from experimental determination. This good agreement between the obtained experimental and computational results confirmed the high potential of CFD models for predicting and optimizing the biocatalytic performance of such a reactor.

Triazine-based N-rich covalent organic polymer (TBN-1) was prepared for effective removal and selective detection of Hg2+ from model solutions. The π-π conjugated structure formed by alternating electron-deficient triazine group and electron-rich benzene group promotes the electron transfer and strong fluorescence. The ultra-high specific surface area and abundant metal complex groups provide excellent adsorption sites for heavy metals. The TBN-1 suspension has obvious fluorescence quenching effect when encountering Hg2+ even when the solutions are treated with co-ions and humic acid. The merits of TBN-1 are unreservedly manifested when further testing the adsorption kinetics of TBN-1 for Hg2+ removal. With the maximum adsorption capacity of 1630 mg g−1, 99.99% of Hg2+ can be removed within 20 min from a 10 ppm solution using TBN-1. The covalent organic polymer (COP) also exhibits a high stability in a wide range of pH and a significant selectivity for Hg2+. About 99.9% Hg2+ can be adsorbed in acidic, co-ions competitive and humic acid contaminated solutions. The TBN-1 can be also reused for at least 5 cycles with acceptable Hg2+ adsorption capacity retention. The mechanism for the excellent Hg2+ adsorption performance of TBN-1 is revealed by coupling physico-chemical model fitting, chemical computation, and experimental characterization, which indicates the coordination and cation-π effects and high electron density of the material to facilitate its complexation with Hg2+. This work offers new prospects for the application of triazine-based COPs for environmental remediation.

Fabricating highly active surface and rapid electron-transfer interface is an appealing route to develop an efficient catalyst to realize visible light driven photocatalytic CO2 reduction into value-added chemicals. Herein, we successfully synthesized the epitaxy of Co9S8 material with tiny CoO by using assembly-calcination method through controlling the amount of added thioacetamide as sulfur resource. As CoO is strongly anchored on the Co9S8, the bonding interaction between Co9S8 and CoO leads to the lattice distortion inside the material, attributing to the Jahn-Teller effect. The as-formed heterojunction between Co9S8 and CoO can create the built-in electric field, which drives the electron transfer from CoO to the Co sites of Co9S8 through the Co-O and Co-S covalent bonds. The existence of CoO also enhances the adsorption affinity of CO2 on the Co9S8 surface, as well as expands the bond length of C = O, which triggers the activation of CO2 molecule on the catalyst surface. While using [Ru(bpy)3]Cl2 (bpy: 2,2′-bipyridine) as photosensitizer and triethanolamine as sacrificial agent, Co9S8/CoO@C displays excellent photocatalytic performance to realize the CO2 reduction to syngas. And the evolution rate of CO and H2 is 1.71 × 104 and 4.75 × 103 μmol h−1 g−1 respectively. The DFT calculations demonstrate that the Co9S8/CoO heterojunction obviously reduces the kinetic barrier for the formation of intermediates during the photochemical reduction of CO2.