Composite Monoliths Research Articles

A Comparison of the Edge Testing of Indirect Composite Layered Zirconia Crowns and Monolithic Zirconia Crowns Without Aging: An In Vitro Study.

Introduction The main reason veneered zirconia restorations fail is due to porcelain veneer chipping. This chipping usually starts from wear marks on the chewing surface. As a result, small cracks under the contact area can grow into larger ones across the veneer layer. The veneer ceramic layer is more vulnerable to fractures because it has lower toughness and slightly lower stiffness compared to the base framework material. Thus, even when there's significant chipping, the main framework material usually stays protected with a thin layer of veneer ceramic on top. The aim of this in vitro study is to compare the edge strength of Monolithic Zirconia Crowns with that of Indirect Composite Layered Zirconia Crowns without aging. Materials and methods This research involved creating 12 hand-layered all-ceramic crowns and 12 indirect composite layered zirconia crowns. The sample size was determined using a G*Power calculation (Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany). The zirconia frameworks (Upcera HT White; UPCERA Dental America Inc., Cerritos, CA, US) were milled and sintered following the manufacturer's instructions. For the all-ceramic group, veneering porcelain (e.max Ceram; Ivoclar Vivadent, Schaan, Liechtenstein) was hand-applied. In contrast, the indirect composite group utilized Ceramage (Shofu, Kyoto, Japan). An Instron 4501 universal testing machine (Instron Corp., Canton, MA, USA) was employed for the edge chipping tests, and a Vickers indenter (Shanghai Toyo Diamond Tools Co., LTD, Shanghai, China) was used to apply the load. The mean value for edge chipping was analyzed using an unpaired t-test with IBM SPSS Statistics for Windows, Version 26 (Released 2019; IBM Corp., Armonk, NY, USA). The normality of the data was confirmed, and statistical significance was set at 0.05. Results Monolithic Zirconia Crowns (Group 1) require significantly more force (mean: 405 N) to induce an edge chip compared to Indirect Composite Layered Zirconia Crowns (Group 2) (mean: 300 N). The 95% confidence interval (83.43261 N to 109.90072 N) confirms the statistical significance of this difference. Conclusion In conclusion, when evaluating restorative materials based on both esthetic and functional criteria, monolithic zirconia stands out due to its combination of strength, esthetic potential, biocompatibility, and versatility.

Simple surface modification of polypropylene pipette tips for anchoring of organic monolithic-based materials for micro-solid-phase extraction

This paper presents a simple method for the surface modification of polypropylene pipette tips by adsorbing a photo-initiator, 2,2-dimethoxy-2-phenylacetophenone (DMPAP), to create reactive sites for the formation of a layer of ethylene dimethacrylate (EDMA) and subsequent monolith polymerization. The types of monomers and the degree of crosslinking dramatically affected the monolith shrinkage and detachment in unmodified tips. Effective surface modification for anchoring monolithic materials to pipette tips was achieved using 15 wt% DMPAP and 10 wt% EDMA in methanol with UV irradiation at 365 nm. The extraction of 5-hydroxyindoleacetic acid, serotonin, and bisphenol A (BPA) using methacrylate and activated charcoal composite monoliths was investigated in terms of breakthrough capacity. The application of monolithic pipette tip micro-solid-phase extraction followed by HPLC-UV was demonstrated for determining BPA leaching from baby-feeding bottles and canned foods. Wide linearity ranging from 0.1 to 100 ng mL−1 (R2 = 0.9998) with good repeatability (% RSD = 3.9 %) and accuracy (% recovery = 93–106 %) was obtained. The limit of detection and limit of quantification were 0.084 and 0.280 ng mL−1, respectively. By varying the sample loading volume from 0.50 to 10.00 mL with eluting volume of 150 μL, a 2-to-52-fold pre-concentration factor was observed.

Cellulose/GO monolith covered with Pd–Pt bimetallic nanocrystals for continuous-flow catalytic reduction of hexavalent chromium

Cellulose monolith materials have interconnected open porous structures with very high porosity, making them attractive structures for use as support materials in heterogeneous catalysis applications. In this study, we developed a highly efficient and reusable continuous-flow reactor for Cr(VI) remediation by combining the advantageous features of cellulose monoliths with suitable reinforcement techniques. We fabricated a porous monolithic cellulose/graphene oxide (GO) composite with a continuous three-dimensional skeletal framework using the thermally induced phase separation technique. Pd nanocrystals were synthesized in situ on the surface of the composite monolith, and then converted to porous Pd–Pt bimetallic nanocrystals through a galvanic replacement reaction. This approach eliminated the need for additional reductants and stabilizers, making the process simpler and more environmentally friendly. Under carefully optimized conditions, the cellulose/GO/Pd–Pt nanocomposite monolith exhibited outstanding performance in continuous-flow reactions for Cr(VI) reduction, achieving a maximum conversion rate of 98 %. Moreover, the nanocomposite monolith-based heterogeneous catalyst exhibited remarkable long-term stability, maintaining its catalytic activity even after extended periods of storage in the dried state. These findings highlight the potential of cellulose-based composite monoliths as versatile and robust support materials for heterogeneous catalysis.

3D-Printed Monoliths Based on Cu-Exchanged SSZ-13 as Catalyst for SCR of NOx

Monoliths manufactured by Direct Ink Writing containing 60% SSZ-13 (SiO2/Al2O3 = 23) and SiO2 with 10% laponite as a binder were investigated as self-standing structured catalysts for NH3-SCR of NOx after a short (4 h) and prolonged (24 h) ion exchange with copper and then compared with pure SSZ-13 exchanged under the same conditions. The catalysts were characterized by morphological (XRD and SEM), textural (BET and pore size distribution), chemical (ICP-MS), red-ox (H2-TPR), and surface (NH3-TPD) analyses. The silica-based binder uniformly covered the SSZ-13 particles, and copper was uniformly distributed as well. The main features of the pure Cu-exchanged SSZ-13 zeolite were preserved in the composite monoliths with a negligible contribution of the binder fraction. NH3-SCR tests, carried out on both monolithic and powdered samples in the temperature range of 70–550 °C, showed that composite monoliths provided very good activity, and that the intrinsic activity of SSZ-13 was enhanced by the hierarchical structure of the composite material.

Polyacrylonitrile-sodium lignosulfonate -derived nitrogen-doped three-dimensional hierarchical porous carbon for supercapacitors

Modulation of pore structure and heteroatom doping are very important strategies to improve the electrochemical properties of carbon electrode materials. This report investigates the use of biomass-derived nitrogen-doped porous carbon materials to address the challenge of the specific capacitance and energy density in supercapacitors. Nitrogen-doped three-dimensional hierarchical porous carbon materials were prepared using a polyacrylonitrile/sodium lignosulfonate composite monolith as a precursor by thermally induced phase separation and subsequent carbonization/activation. This method precisely controls the structure and surface properties of porous carbon materials by regulating the structure of the precursor and situ doping of nitrogen, which is a valuable strategy for the controllable regulation of the pore structure for nitrogen-doped porous carbon materials. The resulting carbon material displayed excellent capacitance performance, exhibiting a high specific capacitance of 325.7F g -1 at a current density of 0.5 A/g, maintaining initial capacitance retention of 90.1 % at a current density of 5 A/g after 10,000 cycles. When investigated for practical applications, the assembled supercapacitor device had a higher energy density (9.88 W h kg- 1), which is higher than commercial carbon-based supercapacitors.

Hierarchical Amino-Functionalized Ionic Liquids@MOF Composite Gel for Catalytic Conversion of CO2.

Hybridization of metal-organic frameworks (MOFs) and homogeneous ionic liquids (ILs) endows the heterogeneous composite with high porosity and accessible multiple active sites (e.g., acidic or basic sites), which exhibits great potential in CO2 capture and conversion. Nevertheless, the majority of MOF composites are synthesized as powders, significantly restricting their practical applications due to inherent problems such as poor handling properties, high pressure drops, and mechanical instability. Thus, it is crucial to shape MOF composites into various monoliths that allow efficient processing, especially for industrial purposes. In this work, a hierarchical ILs@nanoMOF composite gel (H-IL@UiO-66-gel) featuring both intraparticle micropores and interparticle mesopores and multiple active sites was successfully fabricated by a two-step approach. Benefiting from the integrated advantages of the hierarchically porous MOF for enhanced mass transfer and affinity of ILs for activating CO2 molecules, the resultant H-IL@UiO-66-gel exhibits excellent uptake of macromolecules and catalytic activity toward CO2 cycloaddition with epoxides under moderate conditions, far beyond the traditional microporous IL@UiO-66-gel and unfunctionalized H-UiO-66-gel. Furthermore, the H-IL@UiO-66 composite monolith can be effortlessly separated and reused at least three times without depletion of catalytic activity. It is believed that this fabrication method for the shaping of MOF composites is highly versatile and can be extended to other types of MOFs for various application fields.

Cascade phase change from highly-ordered salt hydrate composite monolith for Li-ion battery low-temperature resistance enhancement

The rapid growth of electric vehicles raises an unmet need to enhance low temperature resistance of Li-ion battery (LIB). Herein, highly-ordered and porous boron nitride/polyvinylalcohol (BN/PVA) via directional freeze-drying is fabricated to impregnate with sodium sulfate decahydrate (SSD). The highly-ordered SSD@BN/PVA (HSBP) that is flexible, mechanically strong and electrically insulated possesses high latent heat and leakage-proof temperature. Being inspired by the traditional nucleation theory, a multi-layer structure with gradient freezing points (f.p.s) was built based on HSBP composite along the highly-ordered direction to achieve cascade solidification and controllably thermal energy release. The highly-ordered structure enhances thermal conductivity by 30 times and largely reduces heat dissipation in layers interface. By studying vital factors as solidified heat, f.p. gradient and layer number, a mechanism for cascade solidification is proposed and trilayer HSBP monolith with 3 °C f.p. gradient is proven to be effective for controllable heat release. Consequently, cascade solidification from the multi-layer HSBP monolith could increase temperature holding time by 70 min when battery stops working at −20 °C and improve discharge capacity by 0.71 Ah during cold-start. Therefore, cascade phase change from the multi-layer HSBP monolith shows a significant potential in improving low-temperature resistance of LIB.

Effect of 3D printing process parameters on the mechanical properties of silica/polyethyleneimine composites using direct‐ink writing

AbstractDirect‐ink writing (DIW) 3D printing technology has the advantages of simple process and high efficiency, and enables the molding of materials at room temperature. These characteristics make DIW technology widely applicable in the field of monolithic molding. In this study, a composite slurry of SiO2 and polyethyleneimine (PEI) was molded using direct‐ink writing 3D printing technology. Fourier transform infrared spectroscopy, x‐ray diffraction, and thermogravimetric were used to analyze the structure and thermal characteristics of the composites. Additionally, the study investigated the extrusion flow under different pressures and the impact of ink formula on their rheological behavior and printability, along with an examination of the effects of printing parameters on the mechanical properties of the monolithic structures. The results indicate that the tensile strength of the dumbbell‐shaped specimen increases with greater sample density and reduced nozzle diameter. At a filling angle of ±45°, the void rate is minimal, and the tensile strength reaches a maximum of 1.73 MPa. The tensile strength is maximum when the nozzle diameter is 0.8 mm. On the other hand, the compressive strength of the specimen is directly proportional to the layer thickness – it increases upon reducing the layer thickness. When the layer thickness is 0.3 mm, the compressive strength reaches 0.13 MPa. This study provides insights into direct‐ink writing 3D printing technology and its relationship with the mechanical properties of SiO2/PEI composites monolithic structures.Highlights Self‐standing fumed silica/polyethyleneimine (PEI) composite monoliths were shaped by Direct Ink Writing (DIW) technology. The impact of composite slurry composition on their rheological behavior and printability was examined. Printing parameters effects on mechanical properties of monolithic structures assessed. Significant insights into the relationship between extrusion pressure and forming structure of the composite monoliths are revealed by our research, thereby contributing to the optimization of printing processes.

Hierarchical Macroporous Agarose Materials with Polyethyleneimine-Assisted Multiple Boronate Affinity Binding Sites for the Separation of Neomycin.

Quantification of neomycin residues in food samples demands an efficient purification platform. Herein, hierarchical macroporous agarose monoliths with multiple boronate affinity sites were established for selective separation of neomycin. The silica core was synthesized by "one-step" Stöber procedures followed by modification with amino group and incorporation of polyethyleneimine. A versatile macroporous agarose monolith was prepared by emulsification strategies and functionalized with epoxy groups. After introducing polyethyleneimine-integrated silica nanoparticles onto the agarose monolith, fluorophenylboronic acids were immobilized. The physical and chemical characteristics of the composite monolith were analyzed systematically. After optimization, neomycin showed high binding ability of 23.69 mg/g, and the binding capacity can be manipulated by changing the pH and adding monosaccharides. The composite monolith was subsequently utilized to purify neomycin from the spiked model aquatic products followed by high-performance liquid chromatography analysis, which revealed a remarkable neomycin purification effect, indicating the great potential in the separation of neomycin from complicated aquatic products.

Poly(methylphenylsiloxane)-modified resorcinol-terephthalaldehyde phenolic xerogel monoliths

Fabrication of polymer porous xerogel with environment-friendly and simplified procedure is important target for reducing pollution and production cost. In this research, a sustainable method to prepare thermal insulator of polysiloxane-phenolic composite porous xerogel monoliths was studied by replacing hazardous and volatile formaldehyde with terephthalaldehyde in phenolic component and applying facile ambient drying process. The homogeneous dispersion of poly(methylphenylsiloxane) and resorcinol-terephthalaldehyde in xerogels was achieved by adjusting catalysis condition, water-ethanol content and prepolymer component. Typical poly(methylphenylsiloxane) and resorcinol-terephthalaldehyde composite xerogel monolith had density of about 0.3 g/cm3, 65.4% mass retention rate at 800 °C under nitrogen atmosphere, and thermal conductivity 0.063 W/(m·K) at room temperature. According to Thermogravity analysis coupled with Fourier Transform Infrared Spectra (TG-FTIR), pyrolysis mechanism and structure transformation were revealed. The typical pyrolyzed derivatives at 600 °C and 800 °C well preserved the integrated structure, low density, thermal insulation property, and thermal oxidation stability.

Metal Oxide-Derived MOF-74 Polymer Composites through Pickering Emulsion-Templating: Interfacial Recrystallization, Hierarchical Architectures, and CO2 Capture Performances

Currently, metal-organic framework (MOF)-polymer composites are attracting great interest as a step forward in making MOFs a useful material for industrially relevant applications. However, most of the research is engaged with finding promising MOF/polymer pairs and less with the synthetic methods by which these materials are then combined, albeit hybridization has a significant impact on the properties of the new composite macrostructure. Thus, the focus of this work is on the innovative hybridization of MOFs and polymerized high internal phase emulsions (polyHIPEs), two classes of materials that exhibit porosity at different length scales. The main thrust is the in situ secondary recrystallization, i.e., growth of MOFs from metal oxides previously fixed in polyHIPEs by the Pickering HIPE-templating, and further structure-function study of composites through the CO2 capture behavior. The combination of Pickering HIPE polymerization and secondary recrystallization at the metal oxide-polymer interface proved advantageous, as MOF-74 isostructures based on different metal cations (M2+ = Mg, Co, or Zn) could be successfully shaped in the polyHIPEs' macropores without affecting the properties of the individual components. The successful hybridization resulted in highly porous, co-continuous MOF-74-polyHIPE composite monoliths forming an architectural hierarchy with pronounced macro-microporosity, in which the MOF microporosity is almost completely accessible for gases, i.e., about 87% of the micropores, and the monoliths exhibit excellent mechanical stability. The well-structured porous architecture of the composites showed superior CO2 capture performance compared to the parent MOF-74 powders. Both adsorption and desorption kinetics are significantly faster for composites. Regeneration by temperature swing adsorption recovers about 88% of the total adsorption capacity of the composite, while it is lower for the parent MOF-74 powders (about 75%). Finally, the composites exhibit about 30% improvement in CO2 uptake under working conditions compared to the parent MOF-74 powders, and some of the composites are able to retain 99% of the original adsorption capacity after five adsorption/desorption cycles.

A monolithic composite based on zeolite-like metal-organic framework@divinylbenzene polymer separates azeotropic fluorocarbon mixture efficiently

Organic monolithic columns are mainly used to separate macromolecules; however, many attempts to extend their performance toward small molecules were examined by incorporating micro- and nanoparticles. The incorporation technique enabled utilizing organic monoliths in gas chromatography (GC) for small molecules, which are still scarce. Here, we prepared a composite matrix of capillary monolithic columns of a zeolite-like metal-organic framework with a sodalite topology (sod-ZMOF) and Divinylbenzene polymer (DVB) for GC separations under 0.5 MPa. Relatively short DVB monolithic columns (18 cm long × 0.25 mm i.d.) incorporated with a tiny amount of sod-ZMOF nanoparticles (0.7 and 1.17 wt%) with an average particle size of 225 nm were successfully fabricated and used to separate linear alkanes and polar probes mixtures with increasing resolution up to 3.7 and 5.1 times, respectively, compared to a blank DVB monolithic column. A high-performance separation of linear alkanes series mixture (methane to decane) was exhibited in less than 2 min. McReynolds constants revealed that sod-ZMOF provided the composite monolith with a nonpolar character yielding a negative average polarity value smaller than the standard squalene column. An Excellent retention time of pentane and octane day-to-day reproducibility was achieved during 16 days and over more than 500 runs with RSD% of 2.25% and 3.3% using a composite monolithic column with 5 mg mL−1 sod-ZMOF (5-ZMOF@DVB). In addition, a qualitative determination of the gas mixture content of three commercially available Lighter gas cartridges was performed via the 5-ZMOF@DVB column. Finally, successfully separating an azeotropic freon mixture of difluoromethane (R-32) and pentafluoroethane (R-125) was achieved with a selectivity of up to 4.84. A further thermodynamic study related the preferential adsorption of R-125 to entropic factors rather than enthalpic while trapping inside ZMOF pores. This work sheds light on utilizing the infinite diversity of MOFs and combining their properties with high permeability and easily fabricated organic monoliths for GC separations of light molecules and gasses. Furthermore, the study highlights the role of GC as an easy and fast approach for the preliminary evaluation of the separation efficiency of porous polymers.

Fabrication of a Composite Monolithic Column of Poly (IL@MOF) for Adsorption of Acacetin in Medicinal and Food Homologous Plants

AbstractIn this study, a poly (IL@MOF) composite monolithic column was synthesized using a simple and easy method. By adjusting the ratio of monomers, porogenic agents and cross‐linking agents, a macroporous composite monolith composed of metal organic framework (MOF) and ionic liquids (IL) was constructed. It was used as a high‐performance solid phase extraction (SPE) sorbent for the extraction of acacetin from medicinal and food homologous plants. The proposed SPE‐HPLC method for determination of acacetin had the advantages of high precision (0.06∼1.00 %), wide linear range (0.01∼250 μg mL−1) and low detection limits (3.26 ng mL−1). The poly (IL@MOF) monolithic column had excellent repeatability as an adsorbent. After 300 adsorption/desorption cycles, the corresponding chromatographic signal had no obvious change. These results indicated that the poly (IL@MOF) composite monolithic column was an ideal adsorbents and that the proposed method had potential for the enrichment and purification of flavonoids from medicinal and food homologous plants.

Enhancement of supercapacitive performance of carboxymethyl cellulose-derived porous carbon monoliths by the addition of carbon nanotubes

In this study, a simple and eco-friendly fabrication strategy for the preparation of porous carbon monoliths with 3-dimensional conductive networks was demonstrated. Porous carbon/carbon nanotube composite monoliths (PCCMs) with large specific surface area and hierarchical pore structures were prepared via eco-friendly ice-templating followed by carbonization. The resulting PCCMs showed excellent electrochemical performance due to their well-developed hierarchical porosity and high electrical conductivity following the addition of 1-D carbon nanotubes. In a 3-electrode configuration, the PCCM-derived electrode delivered a specific capacitance of 240 F g−1 at 1 A g−1. In a practical application, the PCCM-based symmetric capacitor exhibited the specific capacitance of 47.0 F g−1, rate capability of 72.7%, power density of 9.5 kW kg−1 and a cycling stability of ∼100% after 20,000 cycles, respectively. These results suggested that the PCCMs can be applied as an active material for high-performance electrical double-layer capacitors.

Montmorillonite-based polymethacrylate composite monoliths as stationary phase materials for food and pharmaceutical analysis in capillary liquid and gas chromatography

This work relates to the preparation of novel and promising stationary phases containing inorganic-organic composites for capillary liquid and gas chromatography. A naturally occurring montmorillonite was introduced to polymethacrylate monoliths, then used under different conditions of GC and HPLC at the same time. The performance of the columns was evaluated for the separation of alkane and alkylbenzene series in GC and capillary HPLC, respectively. While the bare monoliths failed to separate the model analytes, montmorillonite-based polymethacrylate allowed a full separation of the mixtures with Rs≥1.42. The columns were applied for the determination of myrcene and limonene isomers in the peel extracts of some fruits using GC, and for the analysis of active ingredients including aspirin, vitamin-C, caffeine, and ibuprofen extracted from common drugs using capillary HPLC. In GC, fast separation was achieved in 1.0 min with Rs of 6.53. The columns exhibited the best efficiency for myrcene with 20,900 plates/m. Using the capillary HPLC columns, the active ingredients were resolved in 10 min with Rs≥5.72. The efficiency values located between 12,800–21,700 plates/m in all cases. The developed methods were found to be linear in the range of 0.10–10.0 and 0.20–180 μg/mL for GC and HPLC, respectively. In comparison with commercial columns, the results in GC methods reveal that, despite their much shorter length, the prepared columns proved a faster separation with higher efficiency and comparable detection limits and chromatographic resolution. The prepared HPLC capillaries exposed lower run times and detection limits with comparable efficiency and resolution, and consume fewer samples and mobile phase solvents. The results demonstrate that the montmorillonite-based polymethacrylate composites are applicable as stationary phases for routine analysis and quality control of important fields such as food and pharmaceutical samples.

Preparation of composite monoliths of quaternized chitosan and diatom earth for protein separation.

In this study, composite monoliths with porous structures were prepared using quaternized chitosan and diatom earth for protein separation. Quaternized chitosan (N-[(2-hydroxy-3-trimethylammonium)propyl] chitosan chloride) dissolved in water was mixed with diatom earth and crosslinked with glutaraldehyde under low-temperature conditions to form a cryogel. Interconnected porous monoliths were obtained after removing ice crystals from the cryogel. The monoliths adsorbed bovine serum albumin selectively from the solution mixture of bovine serum albumin and bovine ɤ-globulin, and bovine ɤ-globulin was recovered in the flow-through fraction. The adsorption selectivity was enhanced by changing the solution pH from 6.8 to 5.5. The adsorption of bovine serum albumin by the monolith was replicated at least five times following its washing with a buffer containing 400mM NaCl and subsequent regeneration with a 10mM acetate buffer. The composited monolith is a promising adsorbent for the removal of acidic proteins, such as serum albumin contamination in neutral proteins, for example, ɤ-globulins, in bioproduction processes.

Tailoring of Textural Properties of 3D Reduced Graphene Oxide Composite Monoliths by Using Highly Crosslinked Polymer Particles toward Improved CO2 Sorption.

The main constraint on developing a full potential for CO2 adsorption of 3D composite monoliths made of reduced graphene oxide (rGO) and polymer materials is the lack of control of their textural properties, along with the diffusional limitation to the CO2 adsorption due to the pronounced polymers' microporosity. In this work, the textural properties of the composites were altered by employing highly crosslinked polymer particles, synthesized by emulsion polymerization in aqueous media. For that aim, waterborne methyl methacrylate (MMA) particles were prepared, in which the crosslinking was induced by using different quantities of divinyl benzene (DVB). Afterward, these particles were combined with rGO platelets and subjected to the reduction-induced self-assembly process. The resulting 3D monolithic porous materials certainly presented improved textural properties, in which the porosity and BET surface area were increased up to 100% with respect to noncrosslinked composites. The crosslinked density of MMA polymer particles was a key parameter controlling the porous properties of the composites. Consequently, higher CO2 uptake than that of neat GO structures and composites made of noncrosslinked MMA polymer particles was attained. This work demonstrates that a proper control of the microstructure of the polymer particles and their facile introduction within rGO self-assembly 3D structures is a powerful tool to tailor the textural properties of the composites toward improved CO2 capture performance.

A monolith adsorbent of hyper-crosslinked polymer, graphene oxide composite chitosan cryogel for in-syringe solid phase extraction of furfural derivatives from cellulosic biomass hydrolysate

A porous composite monolith adsorbent of hyper-crosslinked polymer, graphene oxide and chitosan cryogel was fabricated for the extraction of furfural and 5-hydroxymethyl-furfural from cellulosic biomass hydrolysate. The composite adsorption materials synergistically enhanced the adsorption of furfural compounds and the porous chitosan cryogel helped to entrap and prevent the loss of the adsorbent composite. The composite monolith adsorbent was in-situ fabricated in a needle hub assembled with a disposable syringe performing in-syringe solid phase extraction. The extracted furfural compounds were quantified by high performance liquid chromatography. The fabricated adsorbent was characterized and the extraction conditions were optimized to achieve the best extraction recovery. In the optimum condition, the developed analytical approach provided linear from 1.0 to 50 ng/L for furfural and 0.5 to 50 ng/L for 5-hydroxymethyl-furfural, with respective detection limits of 0.25 ng/L and 0.20 ng/L. The developed approach was employed for the determination of furfural and 5-hydroxymethyl-furfural extracted from biomass hydrolysate of empty palm fruit bunch cellulose with satisfactory relative recoveries from 90.6 to 101.6 % with the RSDs below 6 %. The developed composite monolith adsorbent is easy to prepare and the extraction format is convenient to use. The good stability of the composite monolith adsorbent enabled reusability for 20 extraction-desorption cycles.

Passive thermal regulation with 3D printed phase change material/cellulose nanofibrils composites

Application of phase change materials (PCM)-containing composite represents a promising passive thermal control strategy to provide indoor thermal comfort without using powered equipment. Yet, the trade-off between high thermal storage density and good thermal stability is the major obstacle that restricts the thermal regulation performance of the current PCM-containing products. This study proposed a facile approach to prepare PCM/cellulose nanofibrils (CNF) ink for 3D printed composite monolith, with very high PCM loading, good thermal stability, and robust mechanical properties. By incorporating a small amount of CNF gel as the stabilizer and viscosity modifier, the CNF-microencapsulated paraffin (model PCM) obtained essential printability to construct tailorable structure using Direct Ink Writing technology. After ice templating and freeze drying, the microencapsulated PCM particles were in-situ embedded in a CNF-assembled scaffold, forming a PCM/CNF composite. The lightweight nature of such scaffold (35.0 mg/cm3 for pure CNF matrix) endowed the composite monolith with high PCM loading (up to 82% with respect to the composite) and high thermal storage capacity (up to 153 J/g). Due to the 3D-interlinked CNF matrix and the coated CNF on PCM particles, the composite monolith not only exhibited high Young's modulus of up to 1.14 MPa but also showed exceptional thermal stability with negligible variation in microscopic morphology and thermal storage capacity, after high temperature conditioning at 80 °C for 30 h.

Preparation of nickel-chelated iminodiacetate-functionalized macroporous agarose monolith using modular and clickable building blocks for affinity separation of histidine-tagged recombinant proteins

Selective separation and purification of protein from complex medium is required to completely investigate the structure and function of the target protein. In this study, a composite macroporous agarose monolith containing iminodiacetate-chelated Ni2+ ligands was synthesized for selective separation and purification of histidine-tagged recombinant proteins. The large and interconnected pores in the monolith enabled fast binding of proteins with high matrix tolerance in treating complex mediums. To realize the selective protein binding, the iminodiacetate was directly conjugated to epoxy-functionalized agarose monolith via simple chemical reactions between epoxy and imino groups. After chelated Ni2+, the composite monolith could bind histidine-tagged recombinant proteins through the coordination interaction between transition metal ions and the imidazole ring of histidine. To further increase the binding capacities of the monolith, a hydrophilic intermediate polymer chain containing multiple iminodiacetate immobilization sites was conjugated to the azide-functionalized agarose monolith via Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. The morphology and chemical composition of the composite agarose monolith were characterized systematically. The protein binding capacities of the obtained composite agarose monolith were subsequently investigated. The binding capacities of the composite agarose monolith towards the model proteins Gp10 and Lys84 were 0.93 and 0.51 mg/mL, respectively. The protein binding of the composite agarose monolith could be manipulated by adjusting the temperature and concentrations of imidazole. These results demonstrate that the composite agarose monolith could be used as an affinity medium for rapid separation and purification of histidine-tagged recombinant proteins from biological samples.