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Epoxy-based nanofiltration (NF) membranes have great potential to allow untapped applications such as the treatment of water/solvent mixtures. However, achieving reproducible membrane performance with concurrent high permeances for water/solvent mixtures and high solute rejections remains challenging. Herein, such a solvent-tolerant NF (STNF) membrane with superior performance characteristics is synthesized through optimizing the non-solvent induced phase separation (NIPS) method by simultaneously curing 2 epoxide building blocks (EPON 1009F (20 wt%) and EPON SU-8 (10 wt%)) with hyperbranched polyethylene imine (PEI) in dimethyl sulfoxide (DMSO). As a multifunctional crosslinker, the hyperbranched PEI, compared to the difunctional linear hexane diamine (HDA), increases the synthesis reproducibility, the membrane flexibility and permeability, offering a remarkable water/DMF (80/20) permeance of 5.7 L m-1 h-1 bar-1 and a rejection of rose bengal (1018 g mol−1) of 93.3%. A decreased permeance and rejection was observed when increasing the solvent content in the water/DMF or water/ethanol feed from 0 to 30 wt%, while a change in water permeance occurred before and after water/solvent filtrations. The epoxy-based membrane is also intrinsically stable in many solvents, and is easy to tune and produce, making it an ideal candidate for the purification of solvent-containing wastewaters from e.g. , the pharmaceutical and chemical industries. • An optimized phase inversion process to prepare epoxy-based solvent-tolerant nanofiltration (STNF). • Membrane formation via epoxy curing with hyperbranched polyethylene imine in DMSO. • Water/DMF (80/20) permeance of 5.7 L m-2 h-1 bar-1 and a RB rejection of 93.3%. • A change in water permeance occurred before and after water/solvent filtrations/ethanol and water/DMF filtrations. • Membranes are stable in toluene, ACN, ethanol and 200 ppm NaOCl in water. [ABSTRACT FROM AUTHOR]

Lignocellulosic materials can be found in a significant fraction of the current low- and intermediate-level radioactive waste. During storage and disposal, radiolytic degradation of such materials can be expected, under oxic or anoxic conditions. This degradation may lead to a significant gas production and changes in the physico-chemical properties of the lignocellulosic materials, which can affect the formation of the known radionuclide-complexing agent isosaccharinic acid (ISA) as well as other (possibly complexing) degradation products during disposal. Hence, in the present work the radiolytic degradation of cellulosic tissues – realistically found in radioactive waste – was investigated under various storage and disposal conditions. For this, cellulosic tissues were exposed to γ-irradiation in gas-tight containers under oxic or anoxic conditions, at an absorbed dose ranging up to 1.4 MGy and at two different dose rates. Our results show that mainly H 2 , CO and CO 2 are produced during irradiation of tissues, though also small amounts of CH 4 are formed. The presence of oxygen does not affect the generation of H 2 , but results in a significant increase in the yields of CO, CO 2 and CH 4. Furthermore, radiation-induced chain scission is observed, causing a decreasing polymerization degree with increasing absorbed dose. Amorphization of the cellulose microstructure occurs significantly at high doses of gamma rays (≥ 0.8 MGy). An increase in the concentration of reducing functional groups is observed with increasing absorbed doses as well. For irradiation under anoxic conditions, this increase is correlated with the observed chain scission. In contrast, additional oxidation processes occur when irradiating cellulosic tissues in the presence of oxygen, resulting in a partially oxidized polymer backbone without causing considerably more chain scission or amorphization. These radiolytic changes to the cellulose structure, both under anoxic and oxic conditions, may enhance its hydrolytic degradation under the hyper-alkaline conditions of long-term final disposal, resulting in a faster production of radionuclide-complexing agents. [Display omitted] • Radiolytic G-values for H 2 , CO, CO 2 and CH 4 generation. • Strong impact of absorbed dose and O 2 presence on gas production, not of dose rate. • Decrease in polymerization degree and crystallinity index with increasing dose. • Increase in concentration reducing groups with dose and O 2 during irradiation. • Enhanced radiolytic CO and CO 2 production in oxygen-rich environment. [ABSTRACT FROM AUTHOR]

This work explored the influence of the citrus pectin degree and pattern of methylesterification on its interaction with Zn 2+ using isothermal titration calorimetry (ITC). Pectin samples with a comparable degree of methylesterification (DM) but distinct distribution patterns of non-methylesterified carboxylic groups (absolute degree of blockiness, DB abs ) were produced through enzymatic (blockwise pattern) or alkaline (random pattern) demethylesterification. The pectin-Zn 2+ interaction was found to be endothermic, in which a positive entropy change compensated for the unfavorable endothermic enthalpy change, driving the interaction between pectin and Zn 2+ . Decreasing pectin DM or increasing DB abs promoted Zn 2+ binding, with the estimated binding capacity (mol Zn 2+ /mol GalA) and binding constant (mM −1 ) being mainly determined by pectin DB abs , rather than DM. ITC was found to be a useful technique to study the pectin-cation interaction, however, low DM pectin samples are sensitive to gelling and therefore more difficult to study. [ABSTRACT FROM AUTHOR]

Chlorination remains a big hurdle in membrane technology as the most commonly used membranes for water purification consist of a polyamide top-layer, which is not fully resistant towards chlorine-induced oxidation. In this work, DOW FILMTEC™ BW30 membrane elements were systematically chlorinated with NaOCl at pilot-scale under acidic conditions (pH4) at 10 bar for 2.5 h. Variations in membrane performance and their physicochemical properties were determined by ATR-FTIR, XPS, WD-XRF, SEM, AFM and zeta-potential measurements. With increasing bleaching concentration, both membrane roughness and chlorine incorporation via N- and ring-chlorination increased, while surface charge remained quasi unaltered. Both water flux and salt passage decreased proportionally over the whole concentration range. Accordingly, positron annihilation lifetime spectroscopy (PALS) revealed a decrease in the size of the top-layer free-volume elements as chlorine concentration increased, confirming, for the first time in a quantitative manner, the so-called tightening effect. The obtained results also show that thin-film composite (TFC) membranes are altered differently when chlorinated under pressure than via simple immersion, as conventionally performed in literature. [ABSTRACT FROM AUTHOR]

This article investigates impact of substituting fumed silica with a cellulosic-crystal innovation in a commercial Vacuum Insulated Panel (VIP) core. High building performance demands have attracted VIP technology investment to increase production capacity and reduce cost. In building retrofit VIPs resolve practical problems on space saving that conventional insulations are unsuitable for. Three challenges exists in fumed silica: cost , low sustainability properties , and manufacture technical maturity . Cellulosic nano-crystal (CNC) technology is in its infancy and was identified as a possible alternative due to a similar physical nano-structure, and biodegradability. The study aim was to determine a performance starting point and establish how this compares with the current benchmarks. Laboratory cellulosic-crystal samples were produced and supplied for incorporation into commercial VIP manufacture. A selection of cellulosic-panels with core densities ranging 127–170 kg/m 3 were produced. Thermal conductivities were tested at a pressure of 1 Pa (0.01 mBar), with the results compared against a selection of fumed silica-VIPs with core densities ranging 144–180 kg/m 3 . Conductivity tests were then done on a cellulosic-VIP with 140 kg/m 3 density, under variable pressures ranging 1–100,000 Pa (0.01–1000 mBar). This investigated panel lifespan performance, with comparisons made to a fumed silica-VIP of similar core density. Manufactured cellulosic-samples were found unsuitable as a commercial substitute, with performance below current standards. Areas for cellulosic nano-material technology development were identified that show large scope for improvement. Pursuit could create a new generation of insulation materials that resolve problems associated with current commercial versions. This is most applicable in building retrofit where large ranges of domestic and commercial cases are marginalised from their construction markets due to impracticalities and high upgrade costs. This being a problem in multiple economies globally. [ABSTRACT FROM AUTHOR]

Integrated CO 2 capture and mineralization is a promising technology for cutting CO 2 emissions and associated environmental impacts. Two major challenges in CO 2 mineralization in aqueous media are (1) the lack of green and energy-efficient processes and (2) limited applications of the produced carbonates. Here, we present a very efficient, environmentally friendly, and convenient integrated CO 2 capture and mineralization method to produce functional calcium carbonate (CaCO 3) particles. We use a gas diffuser reaction setup to bubble CO 2 in liquid media containing reagents such as amino acid as CO 2 absorption promotor, water-soluble polymers as crystal growth modifiers, and Ca2+ ions. Different concentrations of amino acid L-arginine with a fixed CO 2 bubbling rate were investigated for Ca2+ conversion. At the optimized conditions, more than 90% Ca2+ was converted to CaCO 3 within 5 min of CO 2 bubbling at a nominal rate. Additionally, functional carbonates that could be used as dye, heavy metals adsorbents, and functional composite fillers are produced using crystal growth modifiers. The method is simple, efficient, eco-friendly, and could be used for CO 2 /Ca2+-rich industrial waste valorization. [Display omitted] • Arginine is highly efficient in capturing CO 2 in liquid media and subsequent desorption via mineralization. • Simultaneous CO 2 capture and mineralization are performed under ambient conditions. • More than 90% Ca2+ is converted to CaCO 3 within 5 min of CO 2 bubbling. • Biomimetic polymer-mediated crystallization produces functional CaCO 3. • CO 2 absorption promoter arginine can be recovered and reused several times. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sulfonated carbon materials were prepared by the sulfonation of carbonized methyl cellulose. • Sulfonated carbon material exhibits selective sorption of Bi3+ over La3+/Ac3+. • Hydrochloric acid can be applied as the eluent to desorb Bi3+ from sulfonated carbon material. • A high 213Bi yield is achieved via an inverse 225Ac/213Bi column. 213Bi-labeled radiopharmaceuticals for cancer treatment are receiving considerable interest. 213Bi must be separated from the parent radionuclide 225Ac in a radionuclide generator, but the choice of a suitable sorbent material with high chemical and radiolytic stability is challenging. Present work reports on the synthesis of sulfonated carbon materials (SCMs) prepared by carbonization of methyl cellulose at temperatures between 300 and 800 °C, followed by a sulfonation process. These SCMs were evaluated as sorbents in inverse 225Ac/213Bi generators. The sulfonated carbon material prepared at 500 °C (SCM-500) was selected as the most promising candidate sorbent based on its unique aromatic carbon structure, sufficient amount of oxygen-containing functional groups, and selective sorption performance towards La3+/Bi3+. In addition, various variables, including the acidity of the solutions, salt concentrations, and sorption time have been evaluated for separating Bi3+ from La3+ (as a surrogate of Ac3+) by performing batch sorption experiments. SCM-500 was found to exhibit a high sorption Bi3+ selectivity over La3+ at low pH or in the presence of a high concentration of NaNO 3. The optimized conditions in a column tests with this sorbent demonstrated a high chemical 213Bi yield (94 ± 3%) with less than 0.04% 225Ac relative to the eluted 213Bi activity. These results indicate that SCM-500 is a promising material for use in an inverse 225Ac/213Bi radionuclide generator. Furthermore, a conceptual design of an inverse 225Ac/213Bi radionuclide for medical applications is suggested based on the separation properties of SCM-500 and AG MP-50. [ABSTRACT FROM AUTHOR]

[Display omitted] • Efficient separation of La3+/Bi3+ by surface-modified activated carbon materials. • Large differences in La3+/Bi3+ sorption onto the sorbents can be achieved. • Bi3+ can be desorbed by halide ions from sulfonated activated carbon materials. • The sorbents show potential for use in inverse 225Ac/213Bi radionuclide generators. 213Bi is a promising candidate for targeted alpha therapy. However, the search for suitable materials to separate clinically relevant activities of 213Bi from its parent 225Ac remains an ongoing yet critical challenge. This study evaluates sulfonated Norit CA1 (activated carbon) materials (SNCAs) as alternative sorbents for use in 225Ac/213Bi radionuclide generators and gives an overview of their simultaneous sorption/desorption performance towards La3+ and Bi3+. The SNCAs exhibit high and selective uptake of Bi3+ in the presence of NaNO 3 at low pH values. In contrast, the sorption performance for La3+ (which was certified as a non-radioactive surrogate for 225Ac3+) onto SNCAs was more sensitive to the salt concentrations and pH values. The desorption results show that an efficient elution of Bi3+ from SNCAs is achieved using HCl, NaI or NaCl solutions. The experimental sorption data are analysed by various kinetic and isotherm models. The SNCAs exhibit high radiolytic stability, fast sorption kinetics, good durability and recyclability for La3+/Bi3+. This research indicates that SNCAs with sufficient oxygen-containing groups are promising sorbents for the separation of 213Bi in an inverse 225Ac/213Bi radionuclide generator. [ABSTRACT FROM AUTHOR]

Foreign body response (FBR), inflammation, and fibrotic encapsulation of neural implants remain major problems affecting the impedance of the electrode-tissue interface and altering the device performance. Adhesion of proteins and cells (e.g., pro-inflammatory macrophages, and fibroblasts) triggers the FBR cascade and can be diminished by applying antifouling coatings onto the implanted devices. In this paper, we report the deposition and characterization of a thin (±6 nm) sulfobetaine-based coating onto microfabricated platinum electrodes and cochlear implant (CI) electrode arrays. We found that this coating has stable cell and protein-repellent properties, for at least 31 days in vitro , not affected by electrical stimulation protocols. Additionally, its effect on the electrochemical properties relevant to stimulation (i.e., impedance, charge injection capacity) was negligible. When applied to clinical CI electrode arrays, the film was successful at inhibiting fibroblast adhesion on both the silicone packaging and the platinum/iridium electrodes. In vitro , in fibroblast cultures, coated CI electrode arrays maintained impedance values up to five times lower compared to non-coated devices. Our studies demonstrate that such thin sulfobetaine containing layers are stable and prevent protein and cell adhesion in vitro and are compatible for use on CI electrode arrays. Future in vivo studies should be conducted to investigate its ability to mitigate biofouling, fibrosis, and the resulting impedance changes upon long-term implantation in vivo. [ABSTRACT FROM AUTHOR]

Surface modification of cellulose nanocrystals (CNC) by organocatalysed grafting from ring-opening polymerization (ROP) of trimethylene carbonate was investigated. Organocatalysts including an amidine (DBU), a guanidine (TBD), an amino-pyridine (DMAP) and a phosphazene (BEMP) were successfully assessed for this purpose, with performances in the order TBD > BEMP > DMAP, DBU. The grafting ratio can be tuned by varying the experimental parameters, with the highest grafting of 74 % by weight obtained under mild conditions, i.e at room temperature in tetrahydrofuran with a low amount of catalyst. This value is much higher than that of typical ring opening polymerizations of cyclic esters initiated from the surface of cellulose nanoparticles. Additionally, DSC analysis of the modified material revealed the presence of a glass transition temperature, indicative of a sufficient graft length to display polymeric behaviour. This is, to our knowledge, the first example of cellulose nanocrystals grafted with polycarbonate chains. [Display omitted] [ABSTRACT FROM AUTHOR]

Natural fibre-based materials offer various advantages compared to synthetic fibres, however their applications are limited mainly due to their hygroscopic properties, which are affected by their chemical composition, microstructure and the porosity of the plant cells of which the fibre is composed. Therefore, this work investigates the hygroscopic behavior of natural fibres to obtain a better understanding of the relation of the chemical composition of the fibres, their crystallinity, and their equilibrium moisture content. The crystallinity index was determined to include amorphous cellulose into the developed models. Nine biomass samples were selected (flax, hemp, jute, spruce, bamboo, corn stalks, palm leaves, rice husk and wheat straw) to construct models via linear regression to predict the moisture sorption behavior of natural fibres. Thorough statistical (ANOVA, RMSE) analysis showed that the developed models are relevant and descriptive. From all major plant cell wall constituents (lignin, crystalline cellulose, amorphous cellulose and hemicellulose), it is hemicellulose's hygroscopicity that is largely responsible for the moisture uptake of the fibres, with (amorphous) cellulose and lignin playing a (much) smaller role. This study has improved the understanding of the hygroscopic behavior of natural fibres, and is important for optimal application of these fibres in composite materials. • A linear models predicting the EMC absorption and desorption were constructed. • Hemicellulose is the main cell wall constituent affecting EMC desorption and absorption. • Non-crystalline cellulose affects the sorption significantly more than the overall cellulose content. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cationic CNCs could achieve > 90% microalgae flocculation without pH-adjustment. • 0.34-PYR-CNC showed the best performance for both fresh and marine microalgae. • A record-low energy consumption of only 6.7 Wh/m3 was achieved. • Surface patterning can significantly enhance flux, while reducing energy input. • Increasing particle radius can mitigate fouling on the vibrating membrane surface. High energy consumption during harvesting is one of the main bottlenecks for sustainable microalgae production. Membranes can efficiently separate microalgae from liquids with low energy consumption, but membrane fouling remains an important issue. Flocculation prior to membrane filtration can increase membrane fluxes and decrease fouling, thus offering a low-cost and efficient solution to harvest microalgae. Biobased cationic cellulose nanocrystals were successfully used as flocculants for microalgae and were effective over a wide pH-range and for both freshwater and marine microalgae. Such flocculation was for the first time combined with vibration-assisted filtration using a charged, surface patterned membrane, enabling operation at very high flux (95 L/m2 h) using a vibration frequency of only 1 Hz, and even under sub-optimal flocculation conditions. Intermittent vibration decreased energy consumption further while keeping excellent filtration performance to finally achieve a record-low energy consumption for the membrane filtration of only 6.7 Wh/m3, which is >25-times lower than that of normal membrane filtration. Interaction forces revealed that increasing particle size through flocculation prior to membrane filtration can significantly prevent microalgae attachment on the vibrating membrane surface. This work opens a new direction for sustainable microalgae harvesting with an ultra-low energy consumption, combined with a very high microalgae recovery, reduced use of chemicals, and lower membrane investment cost. [ABSTRACT FROM AUTHOR]

This study presents a novel flocculant for harvesting Chlorella vulgaris as model species for freshwater microalgae based on cellulose nanocrystals (CNCs), thus synthesized from a renewable and biodegradable resource. Cationic pyridinium groups were grafted onto CNCs by two separate one-pot simultaneous esterification and nucleophilic substitution reactions. Both types of modified CNCs were positively charged in the pH range 4–11. Both reactions yielded CNCs with a high degree of substitution (up to 0.38). A maximum flocculation efficiency of 100% was achieved at a dosage of 0.1 g g −1 biomass. In contrast to conventional polymer flocculants, cationic CNCs were relatively insensitive to inhibition of flocculation by algal organic matter. The present results highlight the potential of these new type of nanocellulose-based flocculants for microalgae harvesting. [ABSTRACT FROM AUTHOR]

Highlights: [•] PLA fibre melt drawing is easier process than spinning followed by cold drawing. [•] Investigation of properties at 25°C and body temperature (37°C). [•] Investigation of water take-up at variable humidity and its effect on properties. [ABSTRACT FROM AUTHOR]

Highlights: [•] Commercial oil-proof papers prepared with new-type fluorochemicals were investigated. [•] Oil-proof papers had very small surface tensions thanks to fluorochemicals. [•] Fluorochemicals added to the papers were new-type ones containing only perfluoroalkyl chains shorter than 8 carbons. [•] Ink pigment retention on papers was not influenced by oil-proof levels but by surface roughness of papers. [Copyright &y& Elsevier]

Abstract: Cellulose nano-whiskers or nanocrystals are used as a carbon source in a vacuum graphitisation process to surface-modify nano-TiO2 and influence its photoreactivity. In sharp contrast to bulk carbon-modified TiO2 materials, introducing cellulose in a controlled way, i.e., a layer-by-layer deposition process, allows thin film materials to be created with low graphite content, but with strongly suppressed responses to light. The effect is explained by highly effective surface recombination and demonstrated for the I3 −/I− redox system in acetonitrile and for the photo-oxidation of acetate in aqueous media. [Copyright &y& Elsevier]

Abstract: Porous composite films containing cellulose nanofibrils (from sisal) and TiO2 nanoparticles (ca. 6nm diameter) are obtained in a layer-by-layer assembly process. Each layer consists of ca. 0.18μg cellulose nanofibrils and ca. 0.72μg TiO2 (determined by QCMB) and adds a thickness of ca. 16nm (by AFM) to the uniform deposit. The TiO2 nanophase is creating conducting pathways for electrons in a relatively open cellulose structure (ca. 82% open pores) potentially suitable for the immobilization of large redox proteins such as methemoglobin. Methemoglobin is shown to readily adsorb into the cellulose–TiO2 film. However, electrochemical responses for the immobilized methemoglobin in aqueous 0.1M phosphate buffer at pH 5.5 suggest that facile demetallation occurs. Experiments with Fe3+ in the absence of protein result in voltammetric responses indistinguishable from those observed for immobilized methemoglobin. In the presence of ethylenediamine tetraacetic acid (EDTA) the voltammetric signals for the Fe3+ immediately disappear. Complementary experiments conducted in 0.1M acetate buffer at pH 5.5 demonstrate that methemoglobin can indeed be immobilized in electrochemically active form and without demetallation loss of the voltammetric signal in the presence of EDTA. Demetallation appears to occur (i) in the presence of phosphate, (ii) at pH 5.5, (iii) and in the presence of a charged surface. [Copyright &y& Elsevier]

[Display omitted] • Real-time adsorption of expansin and Cel7B on cellulose were followed. • Effects of pH and temperature on expansin adsorption were examined. • Adding zinc ion can improve expansin adsorption and cellulose hydrolysis. • Mechanism of enhanced cellulase activity by expansin and zinc ions was discussed. One of the major limitations of lignocellulose conversion is the relatively low efficiency of cellulases. Expansins can act as an accessory protein to loosen the rigid cellulose structure and promote cellulose hydrolysis. However, the synergistic action of expansin is not well understood. In this study, we employed quartz crystal microbalance with dissipation to real-time monitor the adsorption of Bacillus subtilis expansin (Bs EXLX1) and endoglucanase I (Cel7B) and the hydrolysis of cellulose. The effects of pH, temperature, and zinc ions on the initial adsorption rate and adsorption capacity of Bs EXLX1 were examined. When 36.5 mM of zinc ions was added, the irreversible adsorption ratio of Bs EXLX1 further increased to 4.63 times the value in the absence of zinc ions, whereas the initial adsorption rate and the hydrolysis rate constants of Cel7B could reach 2.16 times and 2.05 times the values in the absence of zinc ions, respectively. [ABSTRACT FROM AUTHOR]

• The real-time adsorption of Cel7A/Cel7B with Bs EXLX1 was studied by QCM-D. • The real-time synergism of Cel7A/Cel7B hydrolysis with Bs EXLX1 was studied by QCM-D. • Competitive adsorption for surface sites exists between Cel7A/Cel7B and Bs EXLX1. • Various quality factors of Cel7A/Cel7B hydrolysis improved by adding Bs EXLX1.. Effective binding between cellulases and cellulose is essential for enzymatic hydrolysis of lignocellulose. Expansin can loosen the cellulose structure and can enhance the efficiency of cellulase. However, possible synergy between cellulases and expansin is not clear. In this work, the real-time adsorption of exoglucanases (Cel7A) or endoglucanases (Cel7B) with Bacillus subtilis expansin (Bs EXLX1) and the enzymatic hydrolysis of cellulose were followed using quartz crystal microbalance with dissipation (QCM-D). Initial adsorption rate, adsorption capacity, and pseudo-steady-state rate of cellulose hydrolysis by Cel7A/Cel7B increased in the presence of Bs EXLX1. When injecting Cel7A or Cel7B together with Bs EXLX1 at a mass ratio of 1:1, the hydrolysis rate was almost 5 times the rate for Cel7A or Cel7B alone at 25 °C. These results increase our understanding of the real-time synergism between cellulases and expansin on cellulose, as well as the impact of their synergy on the enzymatic hydrolysis of cellulose. [ABSTRACT FROM AUTHOR]

The surface initiated ring opening polymerization (SI-ROP) of cellulose nanofibers (CNF) with rac -Lactide under mild conditions using N,N -dimethyl aminopyridine (DMAP) was investigated. The influence of catalyst amount, monomer-to-initiator (cellulose surface –OH groups) ratio, temperature, and cellulose preconditioning (lyophilization vs solvent exchange) were studied to determine the best SI-ROP conditions, and to understand the effect of the parameters on grafting efficiency. The fibers modified after lyophilization had a PLA content comparable to those obtained with traditional metal catalysts (e.g. tin-(II)ethylhexanoate). Starting from a stable dispersion of CNF in dichloromethane obtained through solvent-exchange showed better results at low catalyst amounts. Furthermore, DMAP was readily removed from the products whereas metal catalysts can be hard to remove from the final material, potentially shortening the material lifespan and making it unfit for some applications. Therefore, the use of an easily removable and more efficient organocatalyst can be considered a good alternative to metal catalysts. [ABSTRACT FROM AUTHOR]

The applicability of state-of-the-art water purification membranes in harsh feed streams is limited due to their insufficient chemical robustness. Epoxide chemistry has been recently introduced to achieve pH- and chlorine-stable nanofiltration (NF). This study further investigated the influence of interfacial polymerization (IP) synthesis parameters on the resulting epoxide-based thin-film composite (TFC) membrane structure and performance. Epoxide polymerization could be initiated by N,N,N′,N′ -tetramethyl-1,6-hexanediamine and NaOH. Surprisingly, neither the type of initiator, nor the initiator concentration used during IP, influenced membrane rejection of rose bengal (RB) dye (1017 g mol-1), which was constant at ~ 90%. This consistent RB rejection was primarily determined by annealing of the cross-linked polyimide support by toluene, which is the solvent used during IP. In contrast, the poly(epoxyether) top-layer determined membrane selectivity for methyl orange, a smaller dye of 327 g mol-1. The effect of solvent annealing of the membrane support by diethyl carbonate, dimethyl sulfoxide and m -xylene was also investigated and revealed that the changes induced by solvent contact are physical rather than chemical in nature. This study shows, for the first time, the substantial direct impact of the solvents used during IP to influence support properties and the resulting membrane performance. Solvent annealing can therefore be considered as a tool in membrane fabrication—during IP or as a post-treatment step—to further tune the separation performance for specific applications. • This study shows, the impact of the solvents used during IP on the support membrane properties and the resulting membrane performance. • Epoxide chemistry is a novel platform chemistry for thin-film composite (TFC) membrane synthesis. • Epoxide polymerization can be initiated by both N,N,N′,N′ -tetramethyl-1,6-hexanediamine and NaOH. • Solvent annealing of the XL-PI support by toluene during IP determined the rose bengal rejection of the TFC membrane. • Solvent annealing by toluene, diethyl carbonate, dimethyl sulfoxide and m -xylene causes physical changes in the XL-PI. [ABSTRACT FROM AUTHOR]

• Cationic cellulose nanocrystals are effective flocculants at high ionic strengths. • Cellulose nanocrystals outperform chitosan for flocculation of marine microalgae. • Flocculation is effective over a large pH range 4-10 and salinity range 0- 50 g/L. Flocculation of marine microalgae is challenging because of the high ionic strength of the culture medium. We investigated cationic cellulose nanocrystals (CNCs) as biobased flocculants for the marine microalgae Nannochloropsis oculata , and compared its performance to chitosan. Cationic CNCs induced flocculation at a low dose of 11 mg L-1, while chitosan required a dose of 35 mg L-1. Our cationic CNCs possess a permanent positive charge, allowing flocculation over a wide pH-range (4 to 10). The CNC maximum flocculation efficiency was 90 %, while chitosan achieved > 95 %, attributed to small flocs remaining in suspension for CNCs. However, centrifugation for 1 min at 180 g or gravity filtration using a 30 μm nylon filter after CNC flocculation resulted in the removal of these small, stable flocs (∼150 μm diam) and > 95% harvesting efficiency. Cationic CNCs can thus serve as a sustainable alternative natural flocculant for harvesting both freshwater and marine microalgae. [ABSTRACT FROM AUTHOR]

We examined the similarities and differences of the binding behavior of lysozyme (lys) with pectin varying in local charge density (blockwise distribution and statistical distribution of methoxyl groups, BP and SP) and similar degree of methoxylation (DM). The interaction at ionic strength I = 0.01 and pH 5.1 was found to be mainly electrostatic, associated with an exothermic enthalpy change. BP which is more inclined to self-association binds lys forming strongly associated complex particles with average sizes much larger (10–20 μm) than that of SP. The latter formed with lys small (0.6–3 μm) complex particles or liquid droplets depending on DM. The critical I set and pH set values for BP/lys systems, above which complexes do not form, are not sensitive to DM (approximately 0.1 and 11.5 respectively), whereas for SP/lys systems the critical I set and pH set values decrease significantly with increasing DM. The effect of I on complexation (CP) of lys with BP and SP has a nonmonotonic character. The distribution of BP and SP within the complex particles is irregular and is different for pectin with low and high DM values. The binding constant and stoichiometry ratio (lys/pectin) of the systems with SP are slightly higher than those of BP at the same DM, and these values decrease sharply (50 times) with increasing DM. The large positive changes in entropy in SP/lys systems suggest that the interactions in these systems tend to be more hydrophobic in character at high DM. On the other hand, with BP, a negative enthalpy change, especially for pectin with low charge, suggests the formation of a large quantity of hydrogen bonds or van der Waals interactions during CP. Image 1 • Blockwise distribution of methoxyl groups enhances pectin/lysozyme complex aggregation. • Phase transition compositions depend weakly on methoxyl group distribution. • Critical ionic strength of complexation at low DM is independent of methoxyl group distribution. • Critical pH and ionic strength of complexation with blockwise pectin are insensitive to DM. • Binding constant is larger with statistical methoxyl group distribution. [ABSTRACT FROM AUTHOR]

• Different nitrogen configurations have different binding energy with the intercalated ion. • Nitrogen atoms in the graphene lattice interfere with intercalation. • Poor intercalation is due to binding of the intercalated ion to nitrogen sites. We examine the effect of nitrogen dopants in Few-layer graphene (FLG) cathodes on anion intercalation. Different nitrogen dopant configurations within the FLG were achieved by varying the synthesis parameters and their effects are compared. The dopant configurations of the samples were determined via X-ray photoelectron spectroscopy (XPS) and formation energies were calculated using density functional theory, allowing correlation between cell performance and dopant configuration. The reduced ion intercalation within the nitrogen doped FLG, and thus poor charge/discharge characteristics of nitrogen doped FLG cathodes, is attributed to the reduced mobility of the chloroaluminate ions in the presence of nitrogen dopants. [ABSTRACT FROM AUTHOR]

Throughout the past decades, amphipathic peptide-based hydrogels have proven to be promising materials for biomedical applications. Amphipathic peptides are known to adopt β-sheet configurations that self-assemble into fibers that then interact to form a hydrogel network. A fundamental understanding of how the peptide sequence alters the structural properties of the hydrogels would allow for a more rational design of novel peptides for a variety of biomedical applications in the future. Therefore, the current work investigates how changing the type of amino acid, the amphipathic pattern, and the peptide length affects the secondary structure, fiber characteristics, and stiffness of peptide-based hydrogels. Hereto, seven amphipathic peptides of different sequence and length, four of which have not been previously reported, based on and including the hexapeptide H-Phe-Gln-Phe-Gln-Phe-Lys-NH 2 , are synthesized and thoroughly characterized by circular dichroism (CD), Fourier Transform Infrared (FTIR) spectroscopy, Wide Angle X-ray Scattering (WAXS), Small Angle X-ray Scattering (SAXS), Transmission Electron Microscopy (TEM), and Thioflavin T (ThT) fibrillization assays. The results show that a high amount of regularly spaced β-sheets, a high amount of fibers, and fiber bundling contribute to the stiffness of the hydrogel. Furthermore, a study of the time-dependent fibril formation process reveals complex transient dynamics. The peptide strands structure through an intermediate helical state prior to β-sheet formation, which is found to be concentration- and time-dependent., (© 2024 The Authors. Macromolecular Bioscience published by Wiley‐VCH GmbH.)

The dehydrogenation of long-chain alkanes to olefins and alkylaromatics is a challenging endothermic reaction, typically requiring harsh conditions which can lead to low selectivity and coking. More favorable thermodynamics can be achieved by using a hydrogen acceptor, such as ethylene. In this work, the potential of heterogeneous platinum catalysts for the transfer dehydrogenation of long-chain alkanes is investigated, using ethylene as a convenient hydrogen acceptor. Pt/C and Pt-Sn/C catalysts were prepared via a simple polyol method and characterized with CO pulse chemisorption, HAADF-STEM, and EDX measurements. Conversion of ethylene was monitored via gas-phase FTIR, and distribution of liquid products was analyzed via GC-FID, GC-MS, and 1H-NMR. Compared to unpromoted Pt/C, Sn-promoted catalysts show lower initial reaction rates, but better resistance to catalyst deactivation, while increasing selectivity towards alkylaromatics. Both reaction products and ethylene were found to inhibit the reaction significantly. At 250 °C for 22 h, TON up to 28 and 86 mol per mol Pt were obtained for Pt/C and PtSn 2 /C, respectively, with olefin selectivities of 94% and 53%. The remaining products were mainly unbranched alkylaromatics. These findings show the potential of simple heterogeneous catalysts in alkane transfer dehydrogenation, for the preparation of valuable olefins and alkylaromatics, or as an essential step in various tandem reactions., Competing Interests: The authors declare no conflicts of interests., (This journal is © The Royal Society of Chemistry.)

Medical 225 Ac/ 213 Bi radionuclide generators are designed to provide a local supply of the short-lived 213 Bi for cancer treatment. However, radiation-induced damage to the sorbents commonly used in such radionuclide generators remains a major concern. In this study, the effects of gamma radiation on AG MP-50 cation exchange resin and sulfonated activated carbon (SAC) were studied by analyzing the changes in the morphological characteristics, functional groups, and the La 3+ /Bi 3+ sorption performance, with La 3+ being a suitable non-radioactive substitute for Ac 3+ . The surface sulfonic acid groups of AG MP-50 resin suffered from severe radiation-induced degradation, while the particle morphology was changed markedly after being exposed to absorbed doses of approximately 11 MGy. As a result, the sorption performance of irradiated AG MP-50 for La 3+ and Bi 3+ was significantly decreased with increasing absorbed doses. In contrast, no apparent changes in acquired morphological characteristics were observed for pristine and irradiated SAC based on SEM and XRD characterization. The surface oxygen content ( e.g. , O-C[double bond, length as m-dash]O) of irradiated SAC increased for an absorbed dose of 11 MGy due to free radical-induced oxidation. The sorption performance of pristine and irradiated SAC materials for La 3+ and Bi 3+ remained generally the same at pH values of 1 and 2. Furthermore, the applicability of AG MP-50 and SAC in the 225 Ac/ 213 Bi generators was illustrated in terms of their radiolytic stability. This study provides further evidence for the practical implementation of both AG MP-50 and SAC in 225 Ac/ 213 Bi radionuclide generators., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Two-dimensional (2D) chirality has been actively studied in view of numerous applications of chiral surfaces such as in chiral resolutions and enantioselective catalysis. Here, we report on the expression and amplification of chirality in hybrid 2D metallosupramolecular networks formed by a nucleobase derivative. Self-assembly of a guanine derivative appended with a pyridyl node was studied at the solution-graphite interface in the presence and absence of coordinating metal ions. In the absence of coordinating metal ions, a monolayer that is representative of a racemic compound was obtained. This system underwent spontaneous resolution upon addition of a coordinating ion and led to the formation of a racemic conglomerate. The spontaneous resolution could also be achieved upon addition of a suitable guest molecule. The mirror symmetry observed in the formation of the metallosupramolecular networks could be broken via the use of an enantiopure solvent, which led to the formation of a globally homochiral surface.

Efficient wound repair is crucial for mammalian survival. Healing of skin wounds is severely hampered in diabetic patients, resulting in chronic non-healing wounds that are difficult to treat. High-mobility group box 1 (HMGB1) is an important signaling molecule that is released during wounding, thereby delaying regenerative responses in the skin. Here, we show that dissolving glycyrrhizin, a potent HMGB1 inhibitor, in water results in the formation of a hydrogel with remarkable rheological properties. We demonstrate that these glycyrrhizin-based hydrogels accelerate cutaneous wound closure in normoglycemic and diabetic mice by influencing keratinocyte migration. To facilitate topical application of glycyrrhizin hydrogels on cutaneous wounds, several concentrations of glycyrrhizinic acid in water were tested for their rheological, structural, and biological properties. By varying the concentration of glycyrrhizin, these hydrogel properties can be readily tuned, enabling customized wound care.

The transition to an eco-friendly circular materials system for garbage collected after use from end-users is a serious matter of concern for current society. One important tool in this challenge to achieve a truly circular economy is the chemical recycling of polymers. It has previously been demonstrated that chemical recycling is a feasible alternative to reach carbon circularity, which promotes the maximization of carbon recovery through all possible means. Among the advantages of chemical recycling, one must highlight its ability to selectively attack one or several target functionalities inside a complex mixed stream of polymers to obtain pure monomers, which can then be used to prepare virgin-like polymers as a final product. In previous works from our group, we used a microwave-heated potassium hydroxide in methanol (KMH) system to instantaneously depolymerize PET bottles. The KMH system was also effective for polycarbonate (PC), and intimately mixed PET/PC blends. In the present study, glass fiber reinforced (GFR) PET composites were submitted to depolymerization using the KMH system, and it was verified that more strict conditions were required for full depolymerization of GFR pellets than for pure PET pellets. Evidence of the reorganization of PET chains leading to increased crystallinity were obtained through DSC and WAXD. Surface adhesion of PET and crystallization onto glass fibers led to a different crystalline phase that seems to be more protected against the depolymerization solution, thus increasing the time required for full depolymerization when compared to unreinforced PET. An activation energy of 123 kJ/mol was estimated, in the same range of pristine PET pellets and PET bottles. The optimization of depolymerization conditions permitted 100% depolymerization within 5 min of reaction at 120 °C using 30 mL of KMH solution per g of composite. The green chemistry metrics reflect that our system is more efficient than most of the depolymerization systems found in the literature. The optimal depolymerization conditions here reported for GFR PET composites represent another step towards a total recycling system that includes not only pure polymers but also composites, commonly present in daily life.

Disease research and drug screening platforms require in vitro model systems with cellular cues resembling those of natural tissues. Fibrillar alignment, occurring naturally in extracellular matrices, is one of the crucial attributes in tissue development. Obtaining fiber alignment in 3D, in vitro remains an important challenge due to non-linear material characteristics. Here, we report a cell-compatible, shear stress-based method allowing to obtain 3D homogeneously aligned fibrillar collagen hydrogels. Controlling the shear-stress during gelation results in low strain rates, with negligible effects on the viability of embedded SH-SY5Y cells. Our approach offers reproducibility and tunability through a paradigm shift: The shear-stress initiation moment, being the critical optimization parameter in the process, is related to the modulus of the developing gel, whereas state of the art methods often rely on a predefined time to initiate the alignment procedure. After curing, the induced 3D alignment is maintained after the release of stress, with a linear relation between the total acquired strain and the fiber alignment. This method is generally applicable to 3D fibrillar materials and stress/pressure-controlled setups, making it a valuable addition to the fast-growing field of tissue engineering. STATEMENT OF SIGNIFICANCE: Controlling fiber alignment in vitro 3D hydrogels is crucial for developing physiologically relevant model systems. However, it remains challenging due to the non-linear material characteristics of fibrillar hydrogels, limiting the scalability and repeatability. Our approach tackles these challenges by utilizing a stress-controlled rheometer allowing us to monitor structural changes in situ and determine the optimal moment for applying a shear-stress inducing alignment. By careful parameter control, we infer the relationship between time, induced strain, alignment and biocompatibility. This tunable and reproducible method is both scalable and generally applicable to any fibrillar hydrogel, therefore, we believe it is useful for research investigating the link between matrix anisotropy and cell behavior in 3D systems, organ-on-chip technologies and drug research., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Mixed plastic waste-streams are a main obstacle to a more extensive implementation of polymer recycling. Separating mixed-plastic waste streams demands time and effort at collection or in the recycling plant, while many products consist of multiple polymers that cannot be readily separated. Chemical recycling could provide the key to overcome this issue by targeting specific chemical bonds, enabling selective depolymerization of a single polymer class in a mixture. This work explores the depolymerization of polycarbonate (PC) and polyethylene terephthalate (PET) in separate and in mixed streams. Selective depolymerization of mixed streams composed of PET and PC and one-step separation of their constituent monomers are carried out with outstanding energy efficiency through an inexpensive KOH-in-methanol hydrolysis (KMH) process developed for instantaneous PET hydrolysis. The activation energies for depolymerization of PC and PET pellets are 68.6 and 131.4 kJ mol -1 , respectively. Randomly mixed streams are fully depolymerized within 2 min at 120 °C using 30 mL of depolymerization solution per gram of polymer. The separation of bisphenol A and terephthalic acid is demonstrated in a one-step separation process, yielding 98 and 97 % purity without any secondary reactions detected. Simultaneous depolymerization and selective one-step separation of monomers are also demonstrated for a PET/PC polymer blend prepared by solution casting, showing that this process also works for intimately mixed PET/PC mixtures., (© 2022 Wiley-VCH GmbH.)

Adsorptive separation is a promising lower-energy alternative for traditional industrial separation processes. While carbon-based materials have a long history in adsorptive removal of organic contaminants from solution or gas mixtures, separation using an adsorption/desorption protocol is rarely considered. The main drawbacks are the limited control in bulk adsorption experiments, as often all organic molecules are adsorbed, and lack of desorption methods to retrieve the adsorbed molecules. Using high-resolution on-surface characterization with scanning tunneling microscopy (STM), an increased understanding of the on-surface adsorption behavior under different conditions was obtained. The insight obtained from the nanoscale experiments was used to develop a highly selective separation method using adsorption and desorption on graphite, which was tested for the separation of quinonoid zwitterions. These experiments on adsorptive separation using self-assembly on graphite show its potential and demonstrate the advantage of combining surface characterization techniques with bulk experiments to exploit different possible applications of carbon-based materials., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Understanding the colloidal stability and aggregation behavior of TiO 2 nanoparticles in aqueous suspension is a prerequisite to tune supracolloidal structure formation. While the aggregation mechanism for dried TiO 2 nanopowders is well documented, there is still work to be done to understand TiO 2 nanoparticle aggregation in suspension. Therefore, this work focuses on the colloidal stability and aggregation mechanism of TiO 2 nanoparticle aqueous suspensions prepared using a straightforward one-step sol-gel-based approach over a concentration range of 0.5-5 wt %. Fully crystalline nanoparticles consisting primarily of anatase were obtained. After assessing the colloidal stability of the as-prepared suspensions, small-angle X-ray scattering coupled with fractal analysis was carried out. This analysis showed, for the first time, how the TiO 2 nanoparticle aggregation mechanism─predicted by the diffusion limited cluster-cluster aggregation (DLCA) and diffusion limited particle-cluster aggregation (DLA) theories─depends directly on the starting concentration in the aqueous suspensions. We found that concentrated suspensions favored DLA, while dilute suspensions tend to follow the DLCA mechanism. The effect of the aggregation mechanism on the aggregate shape is also discussed.

Cellulose nanocrystals (CNCs), ribbonlike crystalline nanoparticles, are a biobased material that can be a great alternative to obtaining films with tunable optical properties. Iridescent and light-diffracting films can be readily obtained via the drying of a suspension of these cellulose nanocrystals. The characteristics of the particle deposition process together with the self-assembly in the precluding suspension has a direct effect on the optical properties of the obtained films. Particle deposition onto a substrate is affected by the flow dynamics inside sessile droplets and usually yields a ring-shaped deposition pattern commonly referred to as the coffee-ring effect. We set out to measure and describe the drying kinetics under different conditions. We found that the Marangoni flow inside the droplet was too small to counteract the capillary flow that deposits CNCs at the edges, resulting in the coffee-ring effect, irrespective of the atmospheric humidity. By varying the amount of ethanol in the atmosphere, we were able to find a balance between (1) colloidal stability in the droplet, which is reduced by ethanol diffusion into the droplet, and (2) increasing Marangoni flow relative to capillary flow inside the droplet by changing the droplet surface tension. We could thus make iridescent films with a uniform thickness.