Macroporous Structure Research Articles

Treating waste with waste: Efficient separation of Ni(II) from wastewater by a waste-derived polyimide foam with rationally designed structure

The separation and upcycling of nickel from industrial wastewater is significant because it is harmful to the environment and human health. With the development of special engineering plastics industry, a substantial amount of polyimide (PI) scrap is generated. In this study, an amine and carboxyl functionalized PI (PI-AC) was prepared from waste-derived PI foam for the adsorption and separation of Ni(II). The adsorption performance of PI-AC can be modulated by adjusting the ratio of functional groups. PI-AC demonstrated rapid adsorption kinetics (<5 min) for Ni(II) and effectively adsorbed Ni(II) from real wastewater in column experiments. PI-AC shows a competitive dynamic adsorption capacity for Ni(II) (222.59 mg/g) as compared with most of the reported adsorbents. Furthermore, the successful removal of Ni from low-concentration simulated Ni-containing wastewater (7.18 mg/L) results in a residual Ni concentration (0.001 mg/L) that complies with the emission standard. The porous structure of the PI foam enables rapid adsorption of nickel and column adsorption was successfully achieved. The adsorption performance exhibited maintained stably even after five cycles, demonstrating excellent recoverability. The characterizations, comparison studies, and DFT calculations demonstrated that one nitrogen atom in the amine group and one oxygen atom in the carboxyl group act as a bidentate ligand to chelate with Ni(II). This study opens a new way for the treatment of wastewater using PI foam scrap, which coincides with the idea of “treating the waste with waste”.

Macroporous, Highly Hygroscopic, and Leakage-Free Composites for Efficient Atmospheric Water Harvesting.

Hygroscopic composites based on hygroscopic salts and hydrogels are promising for atmospheric water harvesting (AWH), but their relatively low water production and possible salt leakage hinder real applications. Here, we report highly hygroscopic and leakage-free composites from loading LiCl into emulsion-templated sodium alginate and poly(vinyl alcohol) hydrogels with macroporous structures and interpenetrating polymer networks. The resulting composites exhibited an enhanced moisture uptake (up to 3.4 g g-1) and leakage-free behavior even at an extremely high relative humidity (RH) of 90%. Moreover, the composites showed accelerated adsorption, with high adsorption (0.803 g g-1 water at 25 °C and 90% RH within 1 h) and desorption due to the emulsion-templated, highly interconnected macropores. The hygroscopic composites obtained 1.12 g g-1 water per adsorption-desorption collection cycle and showed high reusability, without obvious deterioration in adsorption, desorption, and collection after 10 cycles. With the presence of carbon nanotubes, solar-driven AWH could be realized, without the requirement of additional energy. The highly hygroscopic and leakage-free composites with enhanced and accelerated adsorption and desorption are excellent candidates for efficient AWH.

Fabric-Enhanced Vascular Graft with Hierarchical Structure for Promoting the Regeneration of Vascular Tissue.

Natural blood vessels have completed functions, including elasticity, compliance, and excellent antithrombotic properties because of their mature structure. To replace damaged blood vessels, vascular grafts should perform these functions by simulating the natural vascular structures. Although the structures of natural blood vessels are thoroughly explored, constructing a small-diameter vascular graft that matches the mechanical and biological properties of natural blood vessels remains a challenge. A hierarchical vascular graft is fabricated by Electrospinning, Braiding, and Thermally induced phase separation (EBT) processes, which could simulate the structure of natural blood vessels. The internal electrospun structure facilitates the adhesion of endothelial cells, thereby accelerating endothelialization. The intermediate PLGA fabric exhibits excellent mechanical properties, which allow it to maintain its shape during long-term transplantation and prevent graft expansion. The external macroporous structure is beneficial for cell growth and infiltration. Blood vessel remodeling aims to combine a structure that promotes tissue regeneration with anti-inflammatory materials. The results in vitro demonstrated that it EBT vascular graft (EBTVG) has matched the mechanical properties, reliable cytocompatibility, and the strongest endothelialization in situ. The results in vitro and replacement of the resected artery in vivo suggest that the EBTVG combines different structural advantages with biomechanical properties and reliable biocompatibility, significantly promoting the stabilization and regeneration of vascular endothelial cells and vascular smooth muscle cells, as well as stabilizing the blood microenvironment.

Ion-imprinted macroporous polyethyleneimine incorporated chitosan/layered hydrotalcite foams for the selective biosorption of U(VI) ions

In order to prevent uranium pollution and recovery uranium resources, it was necessary to find a highly efficient adsorbent for radioactive wastewater treatment. Herein, U(VI) imprinted polyethyleneimine (PEI) incorporated chitosan/layered hydrotalcite composite foam (IPCL) was synthesized by combining ion-imprinting and freeze-drying techniques. IPCL has a high amino/imino content and an ultralight macroporous structure, making it capable of efficiently adsorbing U(VI) and easy to separate; Especially after ion-imprinting, vacancies matching the size of uranyl ions were formed, significantly improving U(VI) selectivity. The adsorption isotherms and adsorption kinetics were in accordance with the Freundlich model and PSO model respectively, indicating that heterogeneous adsorption of U(VI) by the adsorbents. The adsorption capacity of IPCL-2 for U(VI) reached 278.8. mg/g (under the conditions of optimal pH 5.0, temperature of 298 K, contact time of 2 h, and adsorbent dosage of 0.2 g/L), which is almost double of that for the non-imprinted foam (PCL-2, 138.2 mg/g), indicating that IPCL-2 can intelligently recognize U(VI). The heterogeneous adsorption mechanism of U(VI) by IPCL-2 involves complexation, ion-exchange and isomorphic substitution. The adsorption of U(VI) by IPCL-2 is spontaneous and endothermic. IPCL-2 has excellent adsorption performance for U(VI), and is a promising adsorbent for radioactive pollution control.

Modulating Intrinsic Defect Structure of Fibrous Hard Carbon for Super‐Fast and High‐Areal Sodium Energy Storage

AbstractCreating defects by heteroatom doping is commonly approved in respect of enhancing fast sodium‐ion storage of carbonaceous anodes ascribing to rich external defects, but the contribution of intrinsic carbon defects (e.g., vacancy) in improving rate‐capability has rarely been investigated. Here, a bio‐derived fibrous hard carbon with high‐reversible intrinsic defects is synthesized via metal‐assisted‐catalytic strategy. It is found that sp2‐hybridized carbon is united through catalytic‐tuning during thermal‐etching process along with the formation of low‐potential planar intrinsic carbon defects (vacancies and non‐hexagonal carbon rings) by sacrificing poor‐reversible carbon edges. Such integrated structures greatly improve the reversibility of defective sites and charge transfer kinetics, thus enhancing the slope sodium‐storage capacity of carbon below 1 V even at high current densities. Thus‐obtained fibrous carbon anodes enable boosted initial coulombic efficiency (≈90%) and ultrahigh‐rate capability in both half‐ (222.2 mAh g−1at 50 A g−1) and full‐cell (200 C, charged/discharged in ≈10 s). Interestingly, compared with meso‐/macroporous structures, such micropore‐dominated carbon fibers are more beneficial for fabricating high‐mass‐loading, crack‐free thick electrodes (&gt;10 mg cm−2) with considerable areal‐capacity over 3.0 mAh cm−2. Paired with high‐loading Na3V2PO4 cathode (14.4 mg cm−2), full‐cell achieves admirable areal‐capacity over 1.4 mAh cm−2 and peak areal‐energy/power‐density of 3.2/74 mW cm−2.

Highly Macroporous Polyimide with Chemical Versatility Prepared from Poly(amic acid) Salt-Stabilized High Internal Phase Emulsion Template.

Macroporous polymers have gained significant attention due to their unique mass transport and size-selective properties. In this study, we focused on Polyimide (PI), a high-performance polymer, as an ideal candidate for macroporous structures. Despite various attempts to create macroporous PI (Macro PI) using emulsion templates, challenges remained, including limited chemical diversity and poor control over pore size and porosity. To address these issues, we systematically investigated the role of poly(amic acid) salt (PAAS) polymers as macrosurfactants and matrices. By designing 12 different PAAS polymers with diverse chemical structures, we achieved stable high internal phase emulsions (HIPEs) with >80 vol % internal volume. The resulting Macro PIs exhibited exceptional porosity (>99 vol %) after thermal imidization. We explored the structure-property relationships of these Macro PIs, emphasizing the importance of controlling pore size distribution. Furthermore, our study demonstrated the utility of these Macro PIs as separators in Li-metal batteries, providing stable charging-discharging cycles. Our findings not only enhance the understanding of emulsion-based macroporous polymers but also pave the way for their applications in advanced energy storage systems and beyond.

MXene confined microcapsules for uremic toxins elimination

AbstractAdsorbents with high adsorption efficiency and excellent biosafety for biomedical applications are highly required. MXene is a promising candidate owning these advantages, yet pristine MXene faces dilemmas including insufficient utility of surface site as well as limited processibility. Here, we develop MXene‐encapsulated porous microcapsules via microfluidics. The microcapsules have a biomass hydrogel shell that provides robust support for MXene in the core, by which the microcapsules are endowed with high MXene dosage and remarkable biosafety. Additionally, the MXene nanoflakes assemble into a three‐dimensional network via metal ion‐induced gelation, thereby avoiding restacking and significantly improving surface utilization. Moreover, a freeze‐pretreatment of the microcapsules during preparation results in the formation of a macroporous structure in the shell, which can facilitate the diffusion of the target molecules. These features, combined with additional magneto‐responsiveness rendered by the incorporation of magnetic nanoparticles, contribute to prominent performances of the microcapsules in cleaning uremia toxins including creatinine, urea, and uric acid. Thus, it is anticipated that the MXene‐encapsulated microcapsules will be promising adsorbents in dialysis‐related applications, and the combination of microfluidic encapsulation with metal ion gelation will provide a novel approach for construction of hybrid MXene materials with desired functions.

Electronic redistribution and fast delivery enabled by Co0.5Ni0.5Te2 grafting 3D MXene heterostructure for accelerating High-Durability sulfur redox kinetics

Lithium-sulfur (Li-S) batteries are regarded as the most commercially viable energy storage system, but the severe shuttling behavior and sluggish reaction kinetics hinder cycling stability and lifespan. Herein, a brand-new catalytic 3D Co0.5Ni0.5Te2/MXene heterostructure is constructed by uniformly grafting bimetallic telluride nanoparticles onto the MXene nanosheets, inhibiting the restacking of MXene nanosheets. Noticeably, bimetallic elements (Ni/Co) are crosslinking agents that synergistically fulfil and regulate 3D macroporous structure, thus enriching sulfophilic and lithiophilic interactions. The generated 3D porous Co0.5Ni0.5Te2/MXene heterostructure exhibits abundant polar active sites, enhances the chemical adsorption of polysulfides, reduces the transform energy barrier of redox reactions, and provides an accelerated pump for rapid Li+ diffusion at hetero-interface, as sufficient studied by performance analysis, theoretical calculations, and in-situ Raman. Resultantly, the Co0.5Ni0.5Te2/MXene-based batteries exhibit excellent cyclability with a minimum decay ratio of 0.0227 % per cycle during 500 cycles at 1 C, realizing an appealing areal capacity of 8.46 mAh cm−2 even with a high sulfur loading (9.21 mg cm−2) and a lean electrolyte/sulfur ratio (E/S = 6.2 µL mg−1). This work provides an elaborate designed strategy and mechanism insights for simultaneously blocking polysulfides shuttling and enhancing conversion kinetics in Li–S batteries.

Cryogel wound dressings based on natural polysaccharides perfectly adhere to irregular wounds for rapid haemostasis and easy disassembly.

Skin injuries can have unexpected surfaces, leading to uneven wound surfaces and inadequate dressing contact with these irregular surfaces. This can decrease the dressing's haemostatic action and increase the healing period. This study recommends the use of sticky and flexible cryogel coverings to promote faster haemostasis and efficiently handle uneven skin wounds. Alginate cryogels have a fast haemostatic effect and shape flexibility due to their macroporous structure. The material demonstrates potent antibacterial characteristics and enhances skin adherence by adding grafted chitosan with gallic acid. In irregular defect wound models, cryogels can cling closely to uneven damage surfaces due to their amorphous nature. Furthermore, their macroporous structure allows for quick haemostasis by quickly absorbing blood and wound exudate. After giving the dressing a thorough rinse, its adhesive strength reduces and it is simple to remove without causing any damage to the wound. Cryogel demonstrated faster haemostasis than gauze in a wound model on a rat tail, indicating that it has considerable potential for use as a wound dressing in the biomedical area.

Bioprinting Macroporous Hydrogel with Aqueous Two‐Phase Emulsion‐Based Bioink: In Vitro Mineralization and Differentiation Empowered by Phosphorylated Cellulose Nanofibrils

AbstractAqueous two‐phase emulsion (ATPE)‐based bioinks, a creative innovation for bioprinting, enable the fabrication of complex 3D cell‐laden hydrogels with macroporous structure, which promote cellular activities within the scaffold. However, these bioinks intrinsically lack stability and specific biofunctionality, potentially limiting their application for targeted tissue engineering. This study proposes a new perspective by introducing less than 0.1% phosphorylated cellulose nanofibrils (pCNF), a 1D nanofibril top‐down produced from natural biomasses, into a dextran/methacrylated gelatin (GelMA)‐based ATPE system for extrusion‐based bioprinting of preosteoblastic cells, aiming to fabricate macroporous hydrogels with osteogenic differentiation potential. The pCNF that is selectively partitioned in the GelMA phase can not only improve the emulsion stability and alter the rheological behaviors of the ATPE‐based bioink, but also enhance the damping capacity and mineralization ability of the crosslinked hydrogels. Furthermore, macroporous hydrogels with pCNF demonstrate increased cell activity and higher viability in post‐printing, along with higher alkaline phosphatase activity and osteoblastic gene expression. Importantly, the organized interfaces within the hydrogel facilitate the formation of macroscopic biomineralized nodules in vitro. The incorporation of multifunctional pCNF in the ATPE system significantly boosts the physiochemical and biological performance of the macropore‐forming bioink, transforming them into a suitable platform for engineering in vitro bone models.

Titanium dioxide bioceramics prepared by 3D printing method and its structure effect on stem cell behavior

3D printing was widely used for the modification of bioceramic structures. Here, Bioactive titanium dioxide (TiO2) ceramics with macropore structures were prepared by controlling the pore size through 3D printing, and further obtained secondary micropores by altering the sintering temperature. The structures and in vitro bioactivity of materials were characterized, and the properties of the ceramics for osteogenic differentiation of rabbits bone marrow mesenchymal stem cells (rBMSCs) were investigated. The results showed that titanium dioxide ceramics could induce apatite formation in SBF, which indicated it is bioactive. All materials exhibited porous structures, which could promote the proliferation and osteogenic differentiation of rBMSCs. Importantly, the structure with 200 μm pore size significantly promoted the proliferation and adhesion of cells. Furthermore, more secondary micropores formed on the surface of materials with the decreased sintering temperature, which promoted cell proliferation. The pore size of 400 μm significantly upregulated the expression of osteogenesis-related genes, including Col I, ALP, Runx2, and OPN. It had the strongest osteogenic ability when sintered at 1100 °C compared to other groups. This implies that the 3D-printed TiO2 ceramics have good osteogenic properties, and the hierarchical structure consisting of macroscopic pores and secondary micropores can control it well.

Electrostatically directed assembly of macroporous skeleton structured copper selenide for elemental mercury sequestration from coal-fired flue gas

Decontamination of Hg0 from coal-fired flue gas remains an enormous challenge. It is an imperative pursuit to design adsorbents bearing an abundance of accessible chelating sites with a high affinity toward mercury, thus achieving both rapid uptake and high capacity for Hg0. Herein, an electrostatically directed assembly strategy was designed to construct Cu2Se decorated commercial polyurethane sponge (Cu2Se/PUS) as an efficient Hg0 trap. The surface coverage of Cu2Se on the Cu2Se/PUS can be rationally adjusted by turning the charge density of Cu2Se and PUS. The saturated Hg0 adsorption capacity of Cu2Se/PUS was achieved at 217.04 mg g−1 (normalized to the Cu2Se coating amount), which was much higher than that of powdery Cu2Se (43.66 mg g−1). Multiform selenium active sites (Se- and Se2-) and copper-terminated active centers of Cu2Se/PUS co-participated in Hg0 adsorption, instead of the individual role of Se- over powdery Cu2Se. The macroporous skeleton structure and the highly dispersed Cu2Se boosted the diffusion of mercury to the active sites for immobilization, thus accelerating the consumption of multiple active sites on the Cu2Se/PUS. This work not only provided an efficient Hg0 trap but also showed great inspiration for the potential of electrostatically directed assembly methods in constructing adsorbents for diverse environmental remediations.

Emulsion synthetic route of hierarchically porous zeolite-geopolymer composites for Sr2+ decontamination in fixed bed process

The decontamination of wastewater is an important issue for the nuclear industry. The removal of Sr2+, one of the most problematic radioelements, requires hierarchical materials suitable for fixed-bed processes. This article describes a patented emulsion-templating route for the synthesis of Linde Type A (LTA) zeolite-geopolymer composites with a multiscale porosity. By dispersing zeolite particles in an emulsion oil-in-water containing precursors of geopolymer, LTA zeolite–geopolymer composites can be obtained after curing and eliminating the oil phase. The zeolite particles alter the macroporous structure of the materials (replicating the oil droplets) as well as the size of the mesopores of the geopolymer binder. Moreover, zeolite contents higher than 30 wt% induce a crumbling of the material structure. The presence of LTA zeolite particles increases the selectivity of the composites for Sr2+ in very saline media, while the porous network of the material ensures rapid adsorption. The optimal composite prepared here outperformed a commercial sorbent for the Sr2+ decontamination of a saline wastewater through a packed column.

Utilizing Ni(II) complex for metal drug-gel particles in cervical cancer treatment and designing novel drugs through machine learning methods

In the present study, a novel coordination polymer (CP) based on Ni(II), namely, [Ni(L)(D-CAM)(H2O)]n (1) (H2D-CAM = (1R,3S)-1,2,2-trimethylcyclopentane-1,3-dicarboxylic acid and L = 3,6-bis(benzimidazol-1-yl)pyridazine), has been produced successfully through applying a mixed ligand synthesis method via reacting Ni(NO3)2·6H2O with 3,6-bis(benzimidazol-1-yl)pyridazine ligand in the presence of a carboxylic acid co-ligand. Hyaluronic acid (HA) and carboxymethyl chitosan (CMCS) are representatives of natural polysaccharides and have good biocompatibility. Based on the chemical synthesis method, HA/CMCS hydrogel was successfully prepared. SEM showed that the lyophilized gel presented a typical macroporous structure with three-dimensional connected pores, which had unique advantages as a drug carrier. Using paclitaxel as a drug model, we further synthesized a novel paclitaxel-loaded metal gel and evaluated its therapeutic effect on cervical cancer. Finally, novel drugs from the reinforcement learning simulation are suggested to have better biological activity against ovarian cancer due to low affinity energy and stronger interaction strength towards the protein receptor.

Micromotors based on mesoporous silica tubes for thrombus therapy

To solve the problems of traditional drug carriers such as their single structure and lack of graded release, this work designs and synthesizes a kind of microporous–mesoporous silica tube (MST) with a macroporous and mesoporous structure. Then, manganese dioxide (MnO2) nanoparticles prepared using the hydrothermal method are embedded in the macropores to form an MST/Mn micromotor, which is then loaded with heparin and urokinase for thrombolytic therapy. The motion behavior of the micromotor is also investigated. Both static and dynamic thrombolytic therapy are detected, and the results indicate that a better thrombolytic effect can be observed on the MST/manganese micromotor with a motion ability compared with the samples without a motion ability. This research is expected to provide ideas for the design of more effective thrombus treatment agents.

Magnetic porous microspheres enhancing the anaerobic digestion of sewage sludge: Synergistic free and attached methanogenic consortia

The addition of exogenous materials is a commonly reported method for promoting the anaerobic digestion (AD) of sludge. However, most exogenous materials are nano-sized and their use encounters problems relating to a need for continuous replenishment, uncontrollability and non-recyclability. Here, magnetic porous microspheres (MPMs), which can be controlled by magnetic forces, were prepared and used to enhance the methanogenesis of sludge. It was observed that the MPMs were spherical particles with diameters of approximately 100 µm and had a stable macroporous hybrid structure of magnetic cores and polymeric shells. Furthermore, the MPMs had good magnetic properties and a strong solid–liquid interfacial electron transfer ability, suggesting that MPMs are excellent carriers for methanogenic consortia. Experimental results showed that the addition of MPMs increased methane production and the proportion of methane in biogas from AD by 100.0 % and 21.2 %, respectively, indicating the MPMs notably enhanced the methanogenesis of sludge. Analyses of variations in key enzyme activities and electron transfer in sludge samples with and without MPMs in AD revealed that the MPMs significantly enhanced the activities of key enzymes involved in hydrolysis, acidification and methanation. This was achieved mainly by enhancing the extracellular electron transfer to strengthen the proton motive force on the cell membrane, which provides more energy generation for methanogenic metabolism. A careful examination of the variations in the morphology, pore structure and magnetism of the MPMs before and after AD revealed that the MPMs increased the prevalence of many highly active anaerobes, and that this did not weaken the magnetic performance. The microbial community structure and metatranscriptomic analysis further indicated that the acetotrophic methanogens (i.e., Methanosaeta) were mainly in a free state and that CO2-reducing methanogens (i.e., Methanolinea and Methanobacterium) mainly adhered to the MPMs. The above synergistic metabolism led to efficient methanogenesis, which indicates that the MPMs optimised the spatial ecological niche of methanogenic consortia. These findings provide an important reference for the development of magnetic porous materials promoting AD.

Effective degradation of norfloxacin by 3D diatomite plate@polydopamine@WC co-catalytic Fenton at near-neutral pH

To further rush the reduction of Fe3+ and realize the simple application of cocatalyst, 3D diatomite plate@polydopamine@WC (DPW) cocatalysts were prepared using a simple two-step impregnation method to construct a DPW/Fenton system for degrading norfloxacin (NOR) at near-neutral pH (5.5). Characterization results from Scanning electron microscope (SEM), automatic mercury porosimeter, Brunauer-Emmett-Teller (BET) analyzer, and X-ray Photoelectron Spectroscopy (XPS) revealed that 3D DPW possessed a macroporous structure with W0 and W4+ distributed on its surface and within its pores. Under suitable conditions, the DPW/Fenton could degrade 94.98 % of NOR with a reaction rate constant of 0.2087 min−1, being 2.08 and 1.09 times that of MoS2/Fenton and WS2/Fenton, respectively. The Fe2+ content in DPW/Fenton was 1.13 and 1.05 times that of MoS2/Fenton and WS2/Fenton at 15 min. The exposed W0/W4+ sites on DPW enhanced the Fe3+/Fe2+ cycle and increased the H2O2 decomposition rate to 39.82 %. EPR measurements and probe experiments indicated that NOR degradation occurred mainly through·OH-dominated radical pathway. Notably, DPW/Fenton had strong resistance to inorganic salt ions and humic acid, maintaining high degradation rates (68 %, 75 %, and 78 %) for high-ionization-potential contaminants (IP ≥ 9.1 eV) like benzoic acid, terephthalic acid and p-nitrophenol. Impressively, the activity of DPW could be regenerated by the impregnation procedure. Even after 24 reuses, the degradation efficiency of NOR was still above 80 %, and the dissolved concentration of W was below 0.022 mg/L. Interestingly, after being stored for 5 months, the catalytic activity of DPW remained basically unchanged. This work provides a theoretical basis and technical support for the large-scale preparation and convenient application of DPW, as well as the degradation of toxic organic contaminants.

Investigation into the Structure and Properties of Biochar Co-Activated by ZnCl2 and NaHCO3 under Low Temperature Conditions.

Using sodium lignosulfonate as feedstock, ZnCl2 and NaHCO3 co-activated the hierarchical porous carbons (HPCs) were prepared by one-pot pyrolysis with different NaHCO3 dosages (0-4 g) and carbonization temperatures (400-600 °C). Subsequently, phosphotungstate (HPW) was supported with the resulting biochar for the α-pinene hydration reaction to produce α-terpineol. The optimum preparation conditions were determined according to the yield of α-terpineol. The formation mechanism and physicochemical properties of HPCs were analyzed through TG, SEM, XPS, XRD, FT-IR, and N2 adsorption-desorption isotherms. The results demonstrated that NaHCO3 underwent a two-step reaction which liberated a substantial quantity of CO2, thereby enhancing activated carbon's macroporous and mesoporous structures. Simultaneously, NaHCO3 mitigated strong acid gas (HCl) emissions during ZnCl2 activation. Compared with AC450-4:8:0 prepared by ZnCl2 activation alone, the total pore volume of AC450-4:8:2 prepared by co-activation is increased from 0.595 mL/g to 0.754 mL/g and the mesopore rate from 47.7% to 77.8%, which is conducive to reducing the steric hindrance of the hydration reaction and improving the selectivity. Hydration experiments show that the selectivity of α-terpineol is 55.7% under HPW/AC450-4:8:2 catalysis, higher than 31.0% for HPW and 47.4% for HPW/AC450-4:8:0.

Defective ordered macroporous ZIF–8/ZnO heterostructure for enhanced visible–light photo–oxidation performance

Metal–organic frameworks (MOFs) have been extensively used for catalytic reactions due to their abundant structures, regular reticulated channels, and high specific surface areas. They are good platforms for the fabrication of various composites, including metals, oxides, or carbides. Therefore, MOFs can be used as templates to fabricate heterostructures with excellent photocatalytic performance. In this study, the defective ordered macroporous Zeolitic Imidazolate Framework–8/ZnO (D–OM–ZIF–8/ZnO) heterostructure is constructed through the in situ conversion of ordered macroporous ZIF–8 (OM–ZIF–8). The introduction of self–defects into OM–ZIF–8 results in a wide visible–light response band. The ZnO nanoparticles that have formed on the surface of OM–ZIF–8 can effectively regulate surfaces and interfacial states and then construct the heterostructure. The ordered macroporous structure shows considerable advantages for improving carrier mobility, mass transfer rate, and light utilization during photocatalysis. D–OM–ZIF–8/ZnO demonstrates remarkable photocatalytic degradation activity for tetracycline and methylene blue under visible–light. Therefore, our novel construction strategy opens a door for designing ordered microporous MOF–based heterostructures as potential visible–light photocatalysts.

Calcium crosslinked macroporous bacterial cellulose scaffolds with enhanced in situ mineralization and osteoinductivity for cranial bone regeneration

The inherent biological inertness and lack of three-dimensional (3D) macroporous structures greatly hinder the use of pristine bacterial cellulose (BC) as a tissue engineering scaffold for bone regeneration. To address this issue, we developed a simple and effective strategy to fabricate a BC-based scaffold with excellent bioactivity and macroporous structure by crosslinking short-cut BC nanofibers using Ca2+. The Ca2+ crosslinked macroporous BC scaffold (MPBC@Ca) presents better structural stability due to the enhanced cellulose hydration. Importantly, the Ca2+ on the surface of BC nanofibers can serve as an active nucleation site to accelerate the deposition of hydroxyapatite (HAp), which is beneficial for the construction of biomimetic bone tissue extracellular matrix (ECM) microenvironment. The HAp-deposited MPBC@Ca scaffolds (HAp-MPBC@Ca) with biomimetic ECM microenvironment have excellent cytocompatibility and enhanced osteogenic differentiation of stem cells in vitro. Furthermore, the results of in vivo tests revealed that the HAp-MPBC@Ca scaffold has favorable osteoinductivity and accelerates cranial bone tissue regeneration. This study proposes a novel strategy to improve the bioactivity of BC and presents the great potential of biomimetic ECM microenvironment BC-based scaffold for repairing large cranial bone defects.