Rich Porous Structure Research Articles

Structural properties and hypoglycaemic activity of polysaccharides extracted from the fruits of Lycium barbarum L. using various extraction media

The physical and chemical changes that occur during the preparation of polysaccharides are accompanied by changes in structure and biological activity. Different extraction media can affect the bioactivity of polysaccharides by altering their structural properties, including 1D composition, 2D conformation, and 3D morphology. In this study, polysaccharides from the fruits of Lycium barbarum L. were comparatively extracted using water (LBPs-W), 0.1 M HCl (LBPs-Ac), 0.1 M NaOH (LBPs-Al), 0.1% enzyme (LBPs-E), and 6% ionic liquid (LBPs-ILs) aqueous solution, respectively. The physicochemical properties and structures of the five LBPs were compared, and significant differences existed in their chemical components, monosaccharide composition, molecular weight distribution, glycosidic bond ratio, molecular conformation, and morphology. Of note, LBPs-ILs had the highest α-glucosidase, α-amylase, and aldose reductase (AR) inhibitory activities, which may be related to the different monosaccharide compositions, high branching degrees, rich porous structure, and triple helix structure. These results indicated that different media induce differences in structure and function in the process of polysaccharide extraction and dissolution. In addition, ILs are a promising and practical medium to extract hypoglycaemic LBPs from the fruits of Lycium barbarum L. and may be used to extract polysaccharides from other plant resources. ● LBPs extracted from different extraction media showed different structural properties and physiological activity. ● LBPs-ILs had highest α-glucosidase, α-amylase and aldose reductase inhibitory activity. ● ILs was a most suitable media for the extraction of hypoglycemic LBPs from Lycium barbarum L.

Enhanced performance of microbial fuel cells with a bacteria/shape-controllable aligned carbon nanofibers hybrid biofilm

Improving the bacterial loading contents and extracellular electron transfer (EET) efficiency are promising strategies to enhance the overall performance of microbial fuel cells (MFCs). Herein, an aligned carbon nanofiber-bacteria (ACNF-bacteria) hybrid is prepared and used as an efficient anode employing the electrospinning and co-filtration method. The ACNF matrix reveals rich porous structure, large specific surface area, and obviously improved electrocatalytic performance compared to the pristine carbon cloth (CC) anode. Specifically, MFC with the ACNF-bacteria anode achieves a maximum power density of 704 mW m−2, which is 1.7, 2.1 times higher than that of ACNF, CNF and CC anode. Impressively, the coulombic efficiency and chemical oxygen demand (COD) removal rate for ACNF-bacteria anode reach 47.4% and 87.9%, respectively, far exceeding the CC anode (29.3% and 47.6%). Considering all the factors of low cost, facial fabrication, and high-power output, this novel ACNF-bacteria anode provides great potential for high-performance and cost-effective MFCs in a large scale.

Capacitive removal of Pb ions via electrosorption on novel willow biochar–manganese dioxide composites

ABSTRACT Biochar derived from lignocellulosic biomass has been used as a low-cost adsorbent in wastewater treatment applications. Due to its rich porous structure and good electrical conductivity, biochar can be used as a cost-effective electrode material for capacitive deionization of water. In this work, willow biochar was prepared through carbonization of shrub willow chips, activated with potassium hydroxide, and loaded with manganese dioxide (WBC-K-MnO2 nanocomposite). The prepared materials were used to electrochemically adsorb Pb2+ from aqueous solutions. Under the applied potential of 1.0 V, the WBC-K-MnO2 electrode exhibited a high Pb2+ specific electrosorption capacity (23.3 mg/g) as compared to raw willow biochar (4.0 mg/g) and activated willow biochar (9.2 mg/g). KOH activation followed by MnO2 loading on the surface of raw biochar enhanced its BET surface area (178.7 m2/g) and mesoporous volume ratio (42.1%). Moreover, the WBC-K-MnO2 nanocomposite exhibited the highest specific capacitance value of 234.3 F/g at a scan rate of 5 mV/s. The electrosorption isotherms and kinetic data were well explained by the Freundlich and pseudo-second order models, respectively. The WBC-K-MnO2 electrode demonstrated excellent reusability with a Pb2+ electrosorption efficiency of 76.3% after 15 cycles. Thus, the WBC-K-MnO2 nanocomposite can serve as a promising candidate for capacitive deionization of heavy metal contaminated water.

Preparation and Adsorption Properties of Graphene-Modified, Pitch-Based Carbon Foam Composites.

In view of the good adsorption properties of graphene and carbon foam, they were combined to achieve the optimal matching of microstructures. Taking mesophase pitch as a raw material, pitch-based carbon foam was prepared by the self-foaming method. Graphene gel was prepared as the second phase to composite with the carbon foam matrix; graphene-modified, pitch-based carbon foam composites were finally obtained. Graphene gel was dispersed in the rich pore structure of carbon foam to improve its agglomeration and the porosity, and the active sites of the composite were further increased; the adsorption properties and mechanical properties of the composites were also significantly improved. The microstructure and morphology of the composites were studied by SEM, XRD and Raman spectroscopy; the compressive property and porosity were also tested. Methylene blue (MB) solution was used to simulate a dye solution for the adsorption test, and the influence of the composite properties and MB solution on the adsorption property was studied. Results showed that the compressive strength of the composite was 13.5 MPa, increased by 53.41%, and the porosity was 58.14%, increased by 24.15%, when compared to raw carbon foam. When the mass of the adsorbent was 150 mg, the initial concentration of the MB solution was 5 mg/L, and the pH value of the MB solution was 11; the graphene-modified carbon foam composites showed the best adsorption effect, with an adsorption rate of 96.3% and an adsorption capacity of 144.45 mg/g. Compared with the raw carbon foam, the adsorption rate and adsorption capacity of the composites were increased by 158.18% and 93.50%, respectively.

Pore structure modification and characterization of carbon adsorbent prepared by high-sulfur anthracite blending coal

ABSTRACT High sulfur anthracite has high research value and application prospects in the preparation of carbon adsorbent due to its excellent coal quality conditions, but the pore structure changes and sulfur migration dynamics in the preparation process are not clear. In this paper, using SEM, pore structure analysis, Raman, FTIR and XPS, the feasibility of preparing carbon adsorbent from high-sulfur coal blending was analyzed from the perspective of apparent morphology, pore structure parameters, graphite crystal structure, and functional groups and content, while the occurrence form of sulfur in carbon adsorbent was explored. The results showed that the carbon adsorbent prepared from high-sulfur anthracite was mainly microporous, and the specific surface area was up to 1103.23 m2/g, which was the highest among the known high-sulfur coal materials. The degree of disorder of raw coal and the size of graphite crystal particles synergistically formed a rich pore structure. Sulfur in coal mainly exists in the form of thiophene and sulfide. An increase in the bituminous coal proportion promotes the transformation of carbon adsorbent to an alkaline environment. Thiophene sulfur is removed at 900°C, and sulfide is transformed into sulfoxide and sulfone under steam oxidation and Fe catalysis.

Construction of the novel polyimide/Bi2MoO6-OVs p-n type heterojunction aerogel photocatalysts to enhance the photodegradation on organic pollutants driven by the internal electric field

To photodegrade the organic pollution, the Polyimide/Bi 2 MoO 6 -OVs p-n type aerogel heterojunction photocatalysts with rich pore structure and large surface area were synthesized by chemical amide reaction and supercritical ethanol drying technique successfully. The introduction of oxygen vacancies can be beneficial to the activation of molecular oxygen, which can inhibit photo-generated charge recombination to improve photocatalytic efficiency. Furthermore, the formation of Mo-N chemical bond between the coordination of N atoms of heptazine units and Mo atoms of Bi 2 MoO 6 is confirmed by structure analysis. And the ability of the heterojunction photocatalyst to degrade RhB is improved significantly, which is due to photogenerated electron-hole pairs can be quickly separated under the internal electric field within the space charge region under visible light. Simultaneously, the SEM images show the flocculent PI polymer is coated on the surface of flower-like Bi 2 MoO 6 -OVs microsphere, which can expand the light absorption range and enlarge the surface area. This work provides an innovative perspective to construct polymer aerogel with inorganic materials heterojunction photocatalyst with superior photocatalytic activity. • The introduction of oxygen vacancies to Bi 2 MoO 6 is beneficial to the activation of molecular oxygen. • The flocculent PI polymer coated on the surface of flower-like Bi 2 MoO 6 -OVs microsphere is prepared. • The Mo-N chemical bond formation, rich pore structure and large surface area improve photodegradation efficiency.

Preparation and mechanism of biomass-derived graphene-like Li+/Na+ battery anodes controlled by N/O functional groups and interlayer spacing

The universal electrode material can be applied to the traditional Li-ion battery of the emerging alkaline ion battery at the same time, providing a new idea for the development of energy storage systems (EESs). In this study, a porous graphene-like biomass carbon material anode was prepared by chemical blowing strategy and KOH activation method. As the anode of both Li/Na ion batteries, it has excellent cycle stability and extremely high-rate cycle performance. Under the charge-discharge rate of 0.2c, the reversible capacity of Li-ion battery assembled by anode material was 953.2 mA g −1 , and that of Na-ion battery was 378.2 mA g −1 . Under the condition of 10c, the reversible capacity was 352.6 mA g −1 and 127.6 mA g −1 . Its excellent electrochemical performance can be attributed to its wide interlayer spacing, rich pore structure and N/O double doping, and its pseudocapacitance mechanism is conducive to the diffusion of alkaline ions. First-principles calculations further show that its doped structure is beneficial to promote ion adsorption and improve the conductivity of the material. This work has promoted the development of sustainable energy storage materials and provided new ideas for the development of carbon-based anode materials. The porous graphene-like biomass carbon material anode was prepared by chemical blowing strategy and KOH activation method. Combining the effect of interlayer spacing regulation and doped N/O functional group, this carbon-based material has displayed excellent electrochemical performance. When used as anode for lithium-ion batteries, the reversible capacity was 953.2 mA g −1 under 0.2c, and that of Na-ion battery was 378.2 mA g −1 . Under 10c, the reversible capacities of Li-ion and Na-ion batteries were 352.6 mA g −1 and 127.6 mA g −1 . First-principles calculations show that the doped structure is beneficial to promote ion adsorption and improve the conductivity of the material. • Under 0.2c, the reversible capacity of Li-ion battery assembled by anode material was 953.2 mA g −1 , and that of Na-ion battery was 378.2 mA g −1 . • Under 10 c, the reversible capacities of Li-ion and Na-ion batteries were 352.6 mA g −1 and 127.6 mA g −1 . • First-principles calculations show that the doped structure is beneficial to promote ion adsorption and improve the conductivity of the material.

2D metal–organic frameworks and their derivatives for the oxygen evolution reaction

Electrocatalytic oxygen evolution reaction (OER) is a critical half reaction for energy conversion and storage technologies such as water electrolysis, rechargeable metal–air batteries, carbon dioxide reduction reaction, and so on. Unfortunately, large overpotential is needed to overcome the sluggish kinetics of OER. With ultra-thin thickness, large specific surface area, rich and adjustable pore structure, and well-defined metal centers, two dimensional (2D) metal-organic frameworks (MOFs) have been widely investigated for OER. By virtue of the desirable chemical composition and diverse structural type, 2D MOFs are also employed as precursors and sacrificial templates to prepare metal-decorated porous carbon, metal oxides, metal hydroxides, metal sulfides, metal phosphides, and so on. These 2D MOFs derivatives with high surface area and abundant metal sites exhibit excellent OER performance. Herein, the current advances on 2D MOFs and their derivatives as (pre)electrocatalysts are summarized, including the synthetic strategy and OER performance. Moreover, the structure-performance relationships and actual active species or sites of 2D MOFs and their derivatives toward OER are discussed. The current scientific and technological challenges and future perspectives related with 2D MOF and their derivatives in practical applications are also mentioned at last.

From purple sweet potato to sustainable lithium-sulfur batteries

Owing to the intrinsic structural characteristics and natural renewability, biomass materials have been more and more employed as an attractive component of electrode in energy storage devices. Among them, lithium-sulfur (Li-S) batteries are long suffering from several obstacles relating to the sulfur cathode, and biomass-derived carbon could be a cost-effective and fruitful settlement. Therefore, in this work, purple sweet potato is taken as the carbon source. The activation process using KOH and Zn(OAC)2·2H2O are investigated, which provide the resultant carbon material a rich pore structure and a large surface area. After further assembled into a Li-S battery cathode with sulfur infiltration, a high discharge capacity of 1390 mA h g−1 is acquired. The battery also demonstrates excellent rate performance and cycling stability, as well as the environment friendliness due to the application of the sustainable biomass precursors.

Flexible Aluminum-Air Battery Based on Ionic Liquid-Gel Polymer Electrolyte.

There is an urgent demand to develop high-performance flexible batteries for a wide range of contemporary emerging fields, including flexible electronics, wearable sensors, and implantable medical devices. However, the inherent safety and stability issues of traditional organic liquid-based electrolytes make their application in flexible batteries unsatisfactory. Therefore, exploring gel electrolytes with superior ionic conductivity and safety is considered to be the key to the development of flexible batteries. In this paper, two types of high-quality ionic liquid-based gel polymer electrolyte membranes (PVDF-ILs) are created by a conventional solution-casting method, which are further integrated into flexible aluminum-air batteries to guide the interface and process research, and the related discharge properties of two ionic liquid-based electrolyte membrane (PVDF-[C4mpyr]Cl, PVDF-[BMIM]Cl) in different bending states are discussed. The results show that PVDF-ILs have a rich pore structure and interwoven skeleton network, leading to relatively high ionic conductivity (2.97 × 10-3 S cm-1). Moreover, two types of batteries can meet the needs of flexibility, although there is a slight loss of power density under various bending conditions. In general, a PVDF-[C4mpyr]Cl-based flexible aluminum-air battery is suitable for the working conditions of high power and low bending angle, while the PVDF-[BMIM]Cl-based flexible aluminum-air battery is favored for microwatt low-power devices with high flexibility requirements.

Iron-tungsten oxides modified oxygen-rich carbon nitride with defects S-scheme heterojunction for boosting photo-Fenton like removal of pollutants

Owning to excellence of photocatalytic persulfate (PS)-based oxidation processes in pollutant removal, the iron-tungsten oxides modified oxygen-rich carbon nitride with defects (ITOs/OCNv) S-scheme heterojunction composites were successfully prepared, and the photo-Fenton like system (Vis/ITOs/OCNv/PS) was constructed to degrade antibiotic pollutants. Results indicated that the ITOs/OCNv composites exhibited large specific surface area and rich porous structure. In addition, the in-situ introduction of oxygen-rich functional groups and lots of N and O vacancy defects in the composites enhanced the absorption of visible light (Vis) and the electron transfer. Importantly, the formed S-scheme heterojunction improved the separation of photogenerated carriers. The degradation efficiencies of sulfamethazine (SMZ) and ciprofloxacin (CIP) in the optimal Vis/5% ITOs/OCNv/PS system were 99.6 % and 99.5 %, which were 1.69 and 2.34 times that of Vis/5% ITOs/OCNv system (SMZ 58.9 % and CIP 42.6 %) after 40 min, respectively. Results of quenching experiments showed that the main active species were h+, 1O2 and O2− for SMZ and CIP degradation. Moreover, this system exhibited better anti-interference of water substrates and applicability in actual water body. The degradation pathways of CIP were proposed by combining density functional theory calculation with intermediate analysis. Moreover, the ecotoxicities of CIP and its products were evaluated comprehensively. The system showed better broad-spectrum degradation of pollutants, including sulfamethoxazole, atrazine, sulfadimethoxine and bisphenol A, which would provide a new insight for persistent pollutant removal.

Ultrasonic Activated Biochar and Its Removal of Harmful Substances in Environment.

Biochar has been widely used in the fields of environment and energy, and green preparation can make biochar-based materials more environmentally friendly. Particularly, in the low-temperature pyrolysis of biochar, labile C with low biological toxicity is the main influencing factor of bacteria in soil. Therefore, it is worth studying to develop the fabrication technology of low-temperature pyrolysis biochar with rich pore structure. The mechanical effect of ultrasonic cavitation is considered to be an effective strategy for the preparation of biochar. However, the sonochemical effects on biochar remain to be studied. In this review, ultrasonic modification and ultrasonic-chemical modification on biochar has been reviewed. Metal oxide/biochar composites can also be obtained by an ultrasonic-chemical method. It is worth mentioning that there have been some reports on the regeneration of biochar by ultrasound. In addition to ultrasonic preparation of biochar, ultrasound can also trigger the sonocatalytic performance and promote the adsorption ability of biochar for the removal of harmful substances. The catalytic mechanism of ultrasound/biochar needs to be further investigated. For application, biochar prepared by ultrasound has been used for the removal of heavy metals in water, the adsorption of carbon dioxide, and soil remediation.

Preparation and properties of multifunctional polyaspartic acid/waste paper fiber-based superabsorbent composites

Superabsorbent composites (SACs) are widely used for agricultural applications acts as a “miniature soil moisture reservoir” for plants. While these substrates have excellent water retention properties, they often suffer from production costs and a variety of environmental challenges. Herein, polyaspartic acid (PASP), waste paper fibers (WPF) and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) graft copolymerize acrylic acid (AA) to prepare a novel multifunctional PASP-g-P(AA-co-AMPS)/WPF SACs. The synthesis conditions use to prepare the PASP-g-P(AA-co-AMPS)/WPF SACs are optimized, including PASP content, mass ratio of AMPS and AA, initiator content and cross-linker content. In addition, the water retention, salt and acid resistance, reversible swelling and temperature sensitivity of SACs are also investigated and analyzed in detail. Due to the uniform distribution and the rich pore structure, it has a maximum equilibrium adsorption capacity of optimal SACs in distilled water, tap water and NaCl solution (0.9 wt%) are determined to be 731.0 g g−1, 189.2 g g−1 and 81.4 g g−1, respectively. Thus, PASP-g-P(AA-co-AMPS)/WPF SACs exhibit excellent environmental tolerance and provide a promising strategy for sustainable agriculture and desertification control.

A rapid hemostasis for incompressible wounds by microwave-assisting construction of cellulose sponge with chitosan

Rapid hemostasis in incompressible wounds using cellulose sponge, coupled with environmentally friendly and low-cost preparation, remains a challenge. Herein, cellulose sponges loaded with chitosan with abundant rich pore structure and high water absorption capacity were prepared with cellulose carbamate by using gas foaming method. Animal experiments showed that the blood loss and hemostasis time can be significantly shortened from 225 s to 39 s by the plug the incompressible wound using adaptable composite sponges. Scanning electron microscope results showed that the chitosan formed a porous network structure on the surface and between the pores of the cellulose sponge. An obvious inhibitory effects of composite sponge on Escherichia coli and Staphylococcus aureus could effectively reduce wound infection. And the rapid shape recovery ability of the composite sponge was beneficial to sealing the bleeding wound quickly. The results of in vitro hemolytic activity, cytotoxicity and live-dead cell staining showed the composite hemostatic sponges have excellent biocompatibility. In particular, the preparation of cellulose sponge by microwave-assisted method can effectively improve the environmental pollution and cumbersome steps caused by current industrial production. It is expected to be used for rapid hemostasis of non-compressible hemorrhagic wounds.

Facile fabrication of MOF-decorated nickel iron foam for highly efficient oxygen evolution

Metal-organic frameworks (MOFs) have emerged as efficient electrocatalysts due to the features of high specific surface area, rich pore structure and diversified composition. It is still challenging to synthesize self-supporting MOF-based catalysts using simple and low-cost fabrication methods. Herein, we successfully fabricated Ni-doped MIL-53(Fe) supported on nickel-iron foam (Ni-MIL-53(Fe)/NFF) as efficient electrocatalyst. A facile two-step solvothermal method without adding any metal salts was used, which can simplify the fabrication process and reduce the experimental cost. In the fabrication process, the bimetallic Ni-MIL-53(Fe)/NFF was in situ converted from an intermediate NiFe2O4/NFF. The obtained material exhibits outstanding electrocatalytic oxygen evolution performance with a low overpotential of 248 mV at 50 mA cm−2, and a small Tafel slope of 46.4 mV dec−1. This work sheds light on the simple and efficient preparation of bimetallic MOF-based material, which is promising in electrocatalysts.

Ethyl mercaptan removal from gas streams using regenerable Co/Fe modified hexaniobate nanotubes

In this study, Fe and Co/Fe modified H4Nb6O17 nanotubes as high efficiency materials for C2H5SH removal were synthesized by ion exchange-flocculation-calcination process. The results showed that Co/Fe modified H4Nb6O17 nanotubes can enhance removal effect of C2H5SH. C2H5SH breakthrough adsorption capacity of different materials decline as follows: Co/Fe-HNT-0.3 (36.20 mg·g−1) > Co/Fe-HNT-0.5 (33.70 mg·g−1) = Co/Fe-HNT-0.1 (33.70 mg·g−1) > 10 %Fe-HNT (29.96 mg·g−1) > HNT-450 (11.23 mg·g−1) > HNT (6.24 mg·g−1). After four cycle regenerations, the Co/Fe-HNT-0.3 can still maintain C2H5SH removal efficiency of 96.5 %. The characterization results indicated that the loaded metal of Fe and Co/Fe can improve the structure, morphology, thermal stability, and rich pore structure of the H4Nb6O17 nanotubes. It also indicated that Co/Fe oxides were the mainly active substances on H4Nb6O17 nanotubes. These characteristics enhance the adsorption and activation of C2H5SH by Fe and Co/Fe loaded H4Nb6O17 nanotubes. The introduction of Co additives promotes the reduction of Fe3+ and the formed Fe3O4 serve as the main active species to promote the oxidation of adsorbed C2H5SH. This study presents an efficient material of Co/Fe modified H4Nb6O17 nanotubes for the removal of C2H5SH.

Preparation of multi-element doped porous carbon by microwave cross-linking stabilization of disposable surgical masks and its electrochemical properties as sulfur loading

Numerous disposable surgical masks (DSMs) were consumed with the development of COVID-19 epidemic. Non-solid products recovered by pyrolysis is more than twenty species with low added value. Therefore, the search for a reasonable carbonization method can not only alleviate the pressure of global plastic pollution, but also produce considerable economic value. Here it is found that microwave cross-linking can promote the substitution of hydrogen atom in the polymer master chain of DSMs by hydrogen atom, which can reorganize the easily cracked DSMs into sp2-hybridized aromatic carbon, it can maintain 51.2 % carbon yield at1000 ℃. The difference between the DSMs-based porous carbon obtained by in-situ and post-processing N doping was further compared, and it was found that the specific surface area of the activated in-situ doped sample (P-SNO@DSMs) was as high as 2278 m2·g−1, which had rich hierarchical pore structure and high heteroatoms doping rate. Benefiting from the synergistic effect of heteroatoms and hierarchical holes, P-SNO@DSMs sulfur cathode delivers a high specific capacity of 1550 mAh·g−1 at 0.1 C and exhibits excellent long-term cycling performance with the smaller capacity decay of 0.13 % per cycle after 400 cycles. In this work, clean and efficient microwave cross-linking not only realized the efficient recovery of waste DSMs, but also the application of the prepared materials can be broadened by adding additional heteroatomic sources in the process of microwave cross-linking.

Preparation of Polypyrrole/Boron Nitride Composites and Composite Sponges for Efficient Photothermal Utilization

AbstractPhotothermal materials can improve the photothermal conversion efficiency. Here, we design and prepare a photothermal material which has both high light harvesting ability and high thermal conductivity for efficient utilization of light energy. Polypyrrole (PPy) was polymerized in the surface of boron nitride (h‐BN) to form polypyrrole/boron nitride (h‐BN/PPy) composites. The h‐BN/PPy composites can be dispersed in glycol‐water solution to form nanofluids with photothermal conversion properties. To further expand the field of h‐BN/PPy systems. By loading h‐BN and PPy on melamine sponge, MF/h‐BN/PPy composite sponges (MFBP) with high hydrophobicity was creatively obtained. The composite sponges can float on the surface of simulated seawater and has rich porous structure, which is conducive to the escape of water vapor. The evaporation rate of simulated seawater reached 1.21 kg m−2 h−1. Such a composite with simple preparation process and low energy consumption but high photothermal conversion efficiency has promise in photothermal conversion.

Inhibition of polycyclic aromatic hydrocarbon (PAHs) release from sediments in an integrated rice and crab coculture system by rice straw biochar

As persistent organic pollutants that are widely present in the environment and that pose substantial threats to human health, polycyclic aromatic hydrocarbons (PAHs) have received much attention from researchers around the world, but few studies have investigated the PAHs contamination of sediments in rice and crab coculture farming systems. In this study, rice straw biochar was prepared from rice straw, an abundant agricultural waste product, under oxygen-limited conditions at 500 °C. The rice straw biochar was characterized by scanning electron microscopy (SEM), specific surface and pore size analysis (BET), Fourier transform infrared spectroscopy (FTIR), and Raman Spectroscopy. The effect of using rice stalk biochar as a sorbent on the inhibition of the release and migration of PAHs from sediments in a rice and crab coculture system and the biological effects of PAHs within the system were studied for the first time. The results showed that rice straw biochar has a rich pore structure and high specific surface area, and the high-temperature charring method utilized in this study improved the charring and aromaticity of rice straw. The addition of rice straw biochar increased the immobilization of PAHs in sediments by 40.41%–119.62% and inhibited the migration of PAHs from the sediments to the overlying water, which reduced the PAHs content of the pore water at the sediment-water interface by 11.41%–58.73% and reduced the PAHs content of the overlying water in the dissolved and particulate forms by 54.67%–81.03% and 5.08%–55.20%, respectively. The addition of rice straw biochar reduced the biological effectiveness of PAHs in the system, and the enrichment of PAHs in crabs and rice decreased by 38.17–69.53% and 32.12%–97.63%, respectively. In addition, rice straw biochar changed the distribution of PAHs in rice, increasing the PAHs content of the stalks and leaves of rice by 2%–15% and 4%–17%, respectively, while the PAHs content of the roots was reduced by 8%–20%. These results confirm that rice straw biochar can effectively inhibit the migration and release of PAHs from sediments and reduce the bioavailability of phenanthrene (PHE) in integrated farming systems. The results provide theoretical and technical support for the study of straw waste utilization and remediation of PAHs pollution.

Highly Active TAL2 and TAL4 Metal-Organic Framework Derived Bifunctional Oxygen Electrocatalyst

The development of green energy conversion technologies and sophisticated energy storage devices are crucial for a sustainable future. Currently, metal-air batteries and fuel cells promise cost-effective, efficient and clean operation. However, highly active bifunctional noble-metal-free catalyst materials are needed to boost sluggish kinetics of oxygen electrode reactions for replacing conventional benchmark catalysts (Pt/C; RuO2/IrO2). Herein, we report highly active manganese and cobalt containing metal-organic framework (MOF)-derived bifunctional electrocatalyst with rich porous and well-dispersed structure. Mn/Co-containing material displayed excellent electrocatalytic performance toward both oxygen evolution and reduction reactions (Ej=10 =1.66 V; E1/2 = 0.85 V vs RHE, 0.1 M KOH) due to the desired active sites and architecture. Proposed bifunctional electrocatalyst was also tested in Zn-air battery setup and demonstrated outstanding durability within 10 h cycling without any noticeable degradation and great efficiency with high power density.