High-temperature Pyrolysis Process Research Articles

Adsorption of Ibuprofen from Water Using Banana Peel Biochar: Experimental Investigation and Machine Learning Algorithms

Ibuprofen is a significant nonsteroidal anti-inflammatory drug that poses environmental and health risks when present in wastewater because of its persistence and probable toxicity. This study investigates the use of banana peel biochar (BPB) made at 600 °C to 900 °C to eliminate ibuprofen from aqueous solutions. The uniqueness of this work lies in the high-temperature pyrolysis process, which has not been previously explored for the ibuprofen removal efficiency using BPB. The batch experiment was conducted considering initial concentrations, pH, and contact time. The data were compared with different algorithms, with Linear Regression (LR), Support Vector Machines (SVM), Decision Trees (DT), Random Forest (RF), and k-Nearest Neighbor (k-NN) to forecast the performance. The results revealed that banana peel biochar at 900 °C exhibited the highest ibuprofen removal efficiency (69.28 ± 0.83%) at 125 mg/L concentration with the sequence of BPB900 > BPB800 > BPB700 > BPB600. A maximum removal efficiency of 72.67 ± 0.75% was observed at pH 9. Adsorption behavior was analyzed using isotherm and kinetic models, with the Freundlich isotherm model (R2 value 0.9620) indicating heterogeneous adsorption and the pseudo-second-order (PSO) kinetic model (R2 value 0.9969) suggesting that physicochemical interactions govern the process. FTIR analysis ensured the existence of functional groups (hydroxyl, carboxylic, carbonyl, and aromatic rings) responsible for adsorption. Machine learning algorithms, especially RF, demonstrated outstanding performance with 90.07% accuracy in predicting the experimental data. In comparison to other adsorbents, BPB demonstrated superior removal efficiency, underscoring its effectiveness. The study suggests that BPB, particularly at 900 °C, is effective in removing ibuprofen, and due to its sustainable production, it offers a potential solution for wastewater treatment.

Preparation and Electrocatalytic Properties of One-Dimensional Nanorod-Shaped N, S Co-Doped Bimetallic Catalysts of FeCuS-N-C

Metal air batteries have gradually attracted public attention due to their advantages such as high power density, high energy density, high energy conversion efficiency, and clean and green products. Reasonable design of oxygen reduction reaction (ORR) catalysts with high cost-effectiveness, high activity, and high stability is of great significance. Metal organic frameworks (MOFs) have the advantages of large specific surface area, high porosity, and designability, which make them widely used in many fields, especially in catalysis. This paper starts with regulating and optimizing the composition and structure of MOFs. A series of N, S co-doped electrocatalysts FeCuS-N-C were prepared by two high-temperature pyrolysis processes using N-doped carbon hollow nanorods derived from ZIF-8 as the substrate. The one-dimensional nanorod material derived from this MOF exhibits excellent electrocatalytic ORR performance (Eonset = 0.998 V, E1/2 = 0.874 V). When used as the air cathode catalyst for zinc air batteries and assembled into liquid ZABs, the battery discharge curve was calculated and found to have a maximum power density of 142.7 mW cm−2, a specific capacity of 817.1 mAh gZn−1, and a cycling stability test of over 400 h. This study provides an innovative approach for designing and optimizing non-precious metal catalysts for zinc air batteries.

CO2-Mediated Hydrogen Energy Release-Storage Enabled by High-Dispersion Gold-Palladium Alloy Nanodots.

Developing and fabricating a heterogeneous catalyst for efficient formic acid (FA) dehydrogenation coupled with CO2 hydrogenation back to FA is a promising approach to constructing a complete CO2-mediated hydrogen release-storage system, which remains challenging. Herein, a facile two-step strategy involving high-temperature pyrolysis and wet chemical reduction processes can synthesize efficient pyridinic-nitrogen-modified carbon-loaded gold-palladium alloy nanodots (AuPd alloy NDs). These NDs exhibit a prominent electron synergistic effect between Au and Pd components and tunable alloy-support interactions. The pyridinic-N dosage in carbon substrate improves the surface electron density of the alloy catalyst, thus regulating the chemical adsorption of FA molecules. Specifically, the engineered Au3Pd7/CN0.25 demonstrates an outstanding room-temperature FA dehydrogenation efficiency, achieving ≈100% conversion and an initial turnover frequency (TOF) of up to 9049h-1. The versatile AuPd alloy NDs also show the ability to convert CO2, one of the products of FA dehydrogenation, into FA (formate) with a 90.8% yield under mild conditions. Moreover, in-depth insights into the unique alloyed microstructure, structure-activity relationship, key intermediates, and the alloy-driven five-step reaction mechanism involving the rate-determining step of C─H bond cleavage from critical *HCOO species via D-labeled isotope, in situ infrared spectroscopy, and theoretical calculations are investigated.

Multi-core–shell nanoboxes comprising polydopamine-derived C coated NiCo@C and FeCo@C nanohybrid for enhanced electrochemical quantification of nitrofurantoin

The development of a high-performance electrochemical sensing platform for monitoring nitrofurantoin (NFT) levels in various real samples plays an important role in the research community worldwide. To accomplish this objective, the crucial challenge is to construct sensing interfaces with outstanding electrocatalytic capabilities. In the present work, a highly efficient metal@carbon electrocatalyst with porous and multi-core–shell nanobox structure comprising polydopamine (PDA)-derived C coated NiCo@C and FeCo@C nanohybrid (named as NiCo@C/FeCo@C@C) was fabricated by simply pyrolyzing NiCo@FeCo Prussian blue analogues (PBA)@PDA. The carbonization of PDA into carbon shells protected the framework from collapsing during high-temperature pyrolysis process, thus enlarging the specific surface areas and porosity. The NiCo@C/FeCo@C@C composite attained an enhanced electrochemical capability, such as an outstanding electronic conductivity from the double carbon shell with porous structure, a large number of active sites and a high electrocatalytic activity from the metallic alloy nanoparticles, which exhibited a highly sensitive response to NFT. Under optimized experimental conditions, the established NiCo@C/FeCo@C@C electrochemical sensor displayed a wide linear range of 0.05–100 μM for NFT determination, coupled with a low detection limit of 14 nM. The practical feasibility of this sensor was also confirmed by the analysis of NFT in tablet and lake water samples with outstanding recovery rates. Moreover, the sustainability of the sensor was demonstrated through its prominent performance in high reproducibility, selectivity and long-term stability. This study thus introduces an innovative approach for the advance of highly efficient electrocatalysts in the area of electrochemical sensing.

Unlocking the solution-phase molecular transformation of biochar during intensive rainfall events: Implications for the long-term carbon cycle under climate change

The unclear turnover of soluble and solid phases of biochar during increasingly severe climate change (e.g., intensive rainfall) raised questions about the carbon stability of biochar in soil. Here, we present an in-depth analysis of the molecular-level transformations occurring in both the soluble and solid phases of biochar subjected to prolonged wet-dry cycles with simulated rainwater. Biochar properties, including surface functionality and carbon texture, greatly affected the transformation route and led to a distinct stability variation. The rich alkyl −CH3 on the low-temperature biochar (450 °C) was oxidized to hydroxymethyl −CH2OH or formyl −CHO, and the ester −COOC− or peptide −CONHC− bonds were fragmented in the meantime, causing the release of protein- or lipid-like organic carbon and the declined carbon stability (Æ, tested by H2O2 oxidation, from 60.1% to 53.2%). After a high-temperature (750 °C) pyrolysis process, only oxidation of the surface −OH with limited bond breaking occurred after rainwater elution, presenting a marginal composition difference with constant stability. However, the fragile carbon nature of biochar, caused by CO2 activation, led to enhanced fragmentation, oxidation, and hydration, resulting in the release of tannin-like organic carbon, which compromised the carbon storage (Æ decreased from 81.2% to 73.0%). Our findings evaluated the critical transformation of biochar during intensive rainfall, offering crucial insights for designing sustainable biochar and achieving carbon neutrality.

Cerium-regulated Mg3FeO4@biochar activated persulfate to enhance degradation of aqueous tetracycline: The dominant role of cerium

The role of cerium (Ce) in Ce-regulated Mg3FeO4@biochar (CMF@BC) and the mechanism by which CMF@BC activates persulfate (PS) remain unclear. In this work, a novel CMF@BC was synthesized through the simple impregnation–pyrolysis process and utilized as a PS activator for the removal of aqueous tetracycline (TC). Under the optimal degradation conditions, the removal efficiency and mineralization rate of TC reached 92.7 % and 84.2 % within 60 min, respectively, the corresponding rate constant was 0.0487 min−1. The CMF@BC catalyst exhibited extremely high stability and excellent reusability after five cycles. The characterization results identified Fe2+ and oxygen vacancies as major catalytic sites. The Ce dopant inhibited the aggregation of metal ions of Mg3FeO4 during the high-temperature pyrolysis process and the Ce3+/Ce4+ redox cycle promoted Fe2+ regeneration, thus improving the catalyst performance. The degradation process was dominated by non-free radical (1O2) pathways. The possible TC-removal pathway was inferred from liquid chromatography–mass spectrometry results and density functional theory calculations. The toxicity of the degradation products was also evaluated. The CMF@BC catalyst displayed excellent catalytic performance and recyclability, wide pH adaptability, and a low ion-leaching rate, confirming its broad application prospects as a PS activator in antibiotic wastewater treatment.

Preparation, characterization, and thermal decomposition catalytic activity of novel combustion rate catalysts

Abstract The study successfully synthesized a combustion catalyst consisting of copper atoms anchored onto a carbon black support. The 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (CL-20), 1,1-diamino-2,2-dinitroethylene (FOX-7), cyclotetramethylene-tetranitramine, and ammonium perchlorate energetic materials were studied and analyzed using high-temperature pyrolysis process and catalytic oxidation thermal decomposition kinetics analysis. The research results indicate that the addition of the catalyst CB@Cu significantly reduces the activation energy during the pyrolysis process of energetic materials, leading to an earlier decomposition temperature and a significant catalytic effect. After adding catalyst CB@Cu, the endothermic peaks of the three energetic materials shifted toward lower temperatures, but the magnitude of the movement was relatively small. The maximum thermal decomposition temperature has been reduced by 3–5°C compared to that before the addition of the catalyst. At lower temperatures, the catalyst has a better catalytic effect on the energetic materials. The catalyst indicates the formation of electron transfer and the presence of metal Cu ligands, increasing the number of active sites with energetic materials, making the heat release of energetic materials more concentrated and increasing the degree of thermal decomposition.

Application of modified pumice particles with a metal-organic composite prepared by m-phenylenediamine an Iron (II) for photoreduction of Cr(VI) under visible light

Discharging heavy metals into water bodies results in global environmental risks. Hexavalent chromium (Cr(VI)) is known as a harmful substance that poses substantial health hazards to humans. This study aimed to modify the pumice beads using a metal-organic composite synthesized by m-Phenylenediamine (mPD) and Iron (II) (FeCl2·4H2O) via a solvent-free method for photoreduction of the Cr(VI) to Cr(III) in wastewater. In the proposed method, iron (II) ions serve both as an electron generator and as a linker for the polymerization of mPD on the pumice surface in the high-temperature pyrolysis process. The optimum molar ratio of FeCl2·4H2O/mPD and the pyrolysis temperature were determined to be 1 and 700 °C. Moreover, the operative parameters such as pH, hole scavenger (formic acid) dosage, photocatalyst mass, Cr(VI) initial concentration, and reaction time were studied and the optimum condition was obtained as pH of 2.0, hole scavenger dosage of 20 mL L−1, photocatalyst mass of 2 g, chromium concentration of 100 mg L−1 and 13 min for irradiation time. The ability of the photocatalyst to reduce Cr(VI) at a concentration of 50 and 100 mg L−1 under natural sunlight irradiation was also examined and a reduction efficacy of 100 % was achieved under optimum conditions within 40 and 60 min; respectively. Finally, the reusability test was conducted up to 10 cycles, and the results proved the durability and practicality of the prepared photocatalyst. The easy separation, short reaction time, and functioning under natural sunlight exhibited a promising application of the proposed photocatalyst for Cr(VI) reduction.

Steering bidirectional polysulfide conversion in virtue of interface microenvironment of Ni/porous carbon Mott-Schottky heterojunctions

Originating from the notorious shuttle effect and intrinsically sluggish redox kinetics of polysulfides (especially under the conditions of high sulfur loadings and low electrolytes), the low capacity and sulfur utilization efficiency, unsatisfactory rate performance, and unremarkable cycle performance severely hinder the practical commercialization of lithium-sulfur batteries (LSBs). Furnishing rapid electron transfer and mass diffusion in virtue of interface modulation and nanostructure design is an effective strategy to enhance the activity of catalysts. Herein, a Mott-Schottky heterojunction composed of porous carbon (PC)-supported nickel (Ni) nanoparticles was fabricated on a functionalized carbon nanotube sponge (Ni/PC/FCNTS) via adjusting the geometric structure such as the particle size, aggregation state and pore volume (based on the different solvothermal reaction temperature of the Ni-MOF precursor and the high-temperature pyrolysis process). Transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) demonstrated the charge redistribution and a self-generated built-in electric field accelerated electron transfer at the heterogeneous interface between Ni and PC. Meanwhile, the high pore volume of Ni/PC/FCNTS-170 provided a reaction space for rapid ion diffusion and sulfur redox process. Benefiting from the synergistic effect, the derived S@Ni/PC/FCNTS-170 cells manifested excellent rate performance with a capacity of 784.2 mAh g-1 at 2 C and a high areal capacity of 8.09 mAh cm-2 with a high sulfur loading of 17.6 mg cm-2 and low electrolyte/sulfur of 11.3 µL mg-1.

Influence of microplastics and environmentally persistent free radicals on the ability of biochar components to promote degradation of antibiotics by activated peroxymonosulfate

Microplastics (MPs) in sludge can affect the ability of biochar-activated peroxymonosulfate (PMS) to degrade antibiotics. In this work, biochar was prepared by mixing sludge and polystyrene (PS) through hydrothermal carbonization (HTC) and high-temperature pyrolysis processes. The resulting biochar was used to activate PMS to degrade ofloxacin (OFX), levofloxacin (LEV), and pefloxacin (PFX). The addition of PS significantly enhanced the ability of biochar/PMS to degrade antibiotics and the levels of environmentally persistent free radicals (EPFRs, 4.59 × 1020 spin/g) due to the decomposition of PS. The addition of PS resulted in a slight decrease in the specific surface area of biochar (2–3 m2/g on average), but a significant increase in the concentration of EPFRs increased the removal efficiency. The activation of PMS by biochar is dominated by free radicals, accounting for about 70%, in which SO4•- and •OH contribute the most and O2•- the least. However, 1O2 contributes 15–20% to the degradation of antibiotics in non-free radical processes. Overall, the process of biochar/PMS degradation of antibiotics is mainly dominated by free radicals, and the effect of non-free radicals is not obvious. Both hydrochar and pyrocarbon samples showed good hydrophilicity, and this property should improve the ability of active sites on biochar to degrade antibiotics. In the HTC process, PS can decompose during hydrochar preparation, with a maximum reduction value of 40.09%. The three-dimension excitation emission matrix fluorescence spectroscopy (3D-EEM) and total organic carbon (TOC) results show that the protein content in sludge plays a major role in reducing PS, with little effect of polysaccharide and SiO2. There are six to seven degradation intermediates of quinolone antibiotics, which are eventually degraded into CO2, H2O, and inorganic substances. The regeneration experiment showed good reusability of hydrochar and pyrocarbon, further demonstrating the suitability of biochar for the degradation of antibiotics.

Nitrogen-doped carbon nanofiber loaded MOF-derived NiCo bimetallic nanoparticles accelerate the redox transformation of polysulfide for lithium- sulfur batteries

In the electrochemical study of lithium-sulfur (Li-S) batteries, the slow kinetics of the sulfur reduction reaction (SRR) leading to severe shuttle effect of polysulfides remains a major challenge. Catalysts with bimetallic nanoparticles have higher adsorption affinity for lithium polysulfides and hold great potential in improving reaction kinetics. In this study, a nitrogen-doped carbon nanofiber carrier was prepared using high-voltage electrospinning technology, and through in-situ growth and high-temperature pyrolysis process, the carrier material was uniformly loaded with active sites of NiCo bimetallic nanoparticles derived from Metal-organic framework (MOF), aiming to improve the kinetics of sulfur oxidation and reduction and reduce the severe shuttle effect of soluble polysulfides. At the same time, polymethyl methacrylate was added to adjust the pore structure of the carbon nanofibers to form an ideal independent sulfur cathode porous conductive carbon network for rapid ion transport to prevent Li2S deposition and alleviate the volume change during lithiation/delithiation process. Experimental results show that the synergistic catalytic effect of bimetallic nanoparticles can not only rapidly anchor lithium polysulfides throughout the entire reaction process of Li-S batteries, but also reduce the resistance during the reaction process, accelerating the conversion of lithium polysulfides to Li2S deposition. It demonstrates outstanding electrochemical performance, with a first-cycle discharge specific capacity as high as 1431.7 mAh g−1 at a 0.2 C rate, and a Coulombic efficiency of 96%. After 500 cycles, its capacity still maintains at 628.5 mAh g−1, with a decay rate of only 0.11% per cycle. This study provides a feasible insight into the synergistic catalysis of MOF-derived metal nanoparticles, which has important guiding significance and potential impact on the catalysis of Li-S batteries by bimetallic nanoparticles with an independent sulfur cathode structure, and is expected to accelerate the industrialization process of Li-S batteries.

Chemodynamic PtMn Nanocubes for Effective Photothermal ROS Storm a Key Anti-Tumor Therapy in-vivo.

Chemodynamic therapy (CDT) is a new treatment approach that is triggered by endogenous stimuli in specific intracellular conditions for generating hydroxyl radicals. However, the efficiency of CDT is severely limited by Fenton reaction agents and harsh reaction conditions. Bimetallic PtMn nanocubes were rationally designed and simply synthesized through a one-step high-temperature pyrolysis process by controlling both the nucleation process and the subsequent crystal growth stage. The polyethylene glycol was modified to enhance biocompatibility. Benefiting from the alloying of Pt nanocubes with Mn doping, the structure of the electron cloud has changed, resulting in different degrees of the shift in electron binding energy, resulting in the increasing of Fenton reaction activity. The PtMn nanocubes could catalyze endogenous hydrogen peroxide to toxic hydroxyl radicals in mild acid. Meanwhile, the intrinsic glutathione (GSH) depletion activity of PtMn nanocubes consumed GSH with the assistance of Mn3+/Mn2+. Upon 808 nm laser irradiation, mild temperature due to the surface plasmon resonance effect of Pt metal can also enhance the Fenton reaction. PtMn nanocubes can not only destroy the antioxidant system via efficient reactive oxygen species generation and continuous GSH consumption but also propose the photothermal effect of noble metal for enhanced Fenton reaction activity.

Polyaniline as a Nitrogen Source and Lignosulfonate as a Sulphur Source for the Preparation of the Porous Carbon Adsorption of Dyes and Heavy Metal Ions.

Using agricultural and forestry wastes as raw materials, adsorbent materials were prepared for dye adsorption in wastewater, which can minimize the environmental load and fully realize sustainability by treating waste with waste. Taking lignosulfonate as a raw material, due to its molecular structure having more reactive groups, it is easy to form composite materials via a chemical oxidation reaction with an aniline monomer. After that, using a sodium lignosulfonate/polyaniline composite as the precursor, the activated high-temperature pyrolysis process is used to prepare porous carbon materials with controllable morphology, structure, oxygen, sulfur, and nitrogen content, which opens up a new way for the preparation of functional carbon materials. When the prepared O-N-S co-doped activated carbon materials (SNC) were used as adsorbents, the adsorption study of cationic dye methylene blue was carried out, and the removal rate of SNC could reach up to 99.53% in a methylene blue solution with an initial concentration of 100 mg/L, which was much higher than that of undoped lignocellulosic carbon materials, and the kinetic model conformed to the pseudo-second-order kinetic model. The adsorption equilibrium amount of NC (lignosulfonate-free) and SNC reached 478.30 mg/g and 509.00 mg/g, respectively, at an initial concentration of 500 mg/L, which was consistent with the Langmuir adsorption isothermal model, and the adsorption of methylene blue on the surface of the carbon material was a monomolecular layer. The adsorption of methylene blue dye on the carbon-based adsorbent was confirmed to be a spontaneous and feasible adsorption process by thermodynamic parameters. Finally, the adsorption of SNC on methylene blue, rhodamine B, Congo red, and methyl orange dyes were compared, and it was found that the material adsorbed cationic dyes better. Furthermore, we also studied the adsorption of SNC on different kinds of heavy metal ions and found that its adsorption selectivity is better for Cr3+ and Pb2+ ions.

Study on microwave absorption performance of nickel cobalt bimetallic nanosheet arrays @ hydrophilic carbon cloth composite with core-sheath structure

Magnetic metal/carbon matrix composites have gained significant attention as vital microwave absorption materials (MAMs) in recent years, owing to their multifarious microwave loss mechanisms, adjustable chemical composition, and microstructure. In this study, we describe the successful synthesis of nickel-cobalt bimetallic nanosheet arrays @ hydrophilic carbon cloth (NiCo-BNSAs @ HCC) composites with a distinctive core-sheath structure, low density, and high toughness using a solvothermal method followed by a high-temperature pyrolysis process. Despite their low density and high toughness, these composites exhibit outstanding MA properties at low matching thicknesses. Among them, S2 exhibited the minimum reflection loss (RLmin) of −75.4 dB at 1.35 mm, with its optimal effective absorption bandwidth (EAB, RL＜−10 dB) extending to 3.6 GHz at 1.10 mm. Our analysis indicates that the incorporation of NiCo-BNSAs nanosheets not only enhances the multiple scattering of EM waves but also improves interfacial polarization loss and dipole polarization loss. This study provides valuable insights into the rational construction of high-performance magnetic metal/ carbon matrix MAMs with a core-sheath structure.

Co3S4-pyrolysis lotus fiber flexible textile as a hybrid electrocatalyst for overall water splitting

Electrocatalytic overall water splitting (OWS), a pivotal approach in addressing the global energy crisis, aims to produce hydrogen and oxygen. However, most of the catalysts in powder form are adhesively bounding to the electrodes, resulting in catalyst detachment by bubble generation and other uncertain interference, and eventually reducing the OWS performance. To surmount this challenge, we synthesized a hybrid material of Co3S4- pyrolysis lotus fiber (labeled as Co3S4-pLF) textile by hydrothermal and high-temperature pyrolysis processes for electrocatalytic OWS. Owing to the natural LF textile exposing the uniformly distributed functional groups (OH, NH2, etc.) to anchor Co3S4 nanoparticles with hierarchical porous structure and outstanding hydrophily, the hybrid Co3S4-pLF catalyst shows low overpotentials at 10 mA cm−2 (η10, HER = 100 mV η10, OER = 240 mV) alongside prolonged operational stability during electrocatalytic reactions. Theoretical calculations reveal that the electron transfer from pLF to Co3S4 in the hybrid Co3S4-pLF is beneficial to the electrocatalytic process. This work will shed light on the development of nature-inspired carbon-based materials in hybrid electrocatalysts for OWS.

Physicochemical and adsorptive properties of biochar derived from municipal sludge: sulfamethoxazole adsorption and underlying mechanism

Municipal sludge waste could be transformed into useful biochar through pyrolysis process. In this study, municipal sludge-derived biochar (SBC) was successfully synthesized via the one-pot pyrolysis method, and the yield of sludge biochar gradually decreased with the pyrolysis temperature increased from 300°C to 800°C. The sludge biochar exhibited an alkaline surface due to the gradual accumulation of ash and the formation of carbonate and organic anion during high-temperature pyrolysis process. Moreover, the prepared samples were analyzed by different characterization techniques including BET, SEM, and XPS. Adsorption experiments using the optimized biochar sample of SBC800 resulted in a 95% sulfamethoxazole (SMX) removal efficiency and the maximum adsorption capacity of 7033.4 mg/kg, which was 47.5 times higher than that of SBC300. The adsorption process of SBC800 for SMX was more in line with the Freundlich and D-A isotherm model, the whole process was an exothermic reaction. SBC800 could effectively remove SMX through pore filling effect, electrostatic attraction, hydrogen bonding, hydrophobic effect, and π-π EDA interaction. Site energy distribution analysis showed that SMX preferentially occupied the high-energy adsorption site of SBC800, and then gradually diffused to the low-energy adsorption site. This study proposed a sustainable method for recycling municipal sludge for organic pollutant removal.

Polymerization-induced assembly-etching engineering to hollow Co@N-doped carbon microcages for superior electromagnetic wave absorption

Hollow engineering is an effective approach to optimize impedance matching and modify magnetic-dielectric synergy for enhanced wave absorption capability, but the composition and microstructure manipulation of metal-organic frameworks (MOFs)-derived absorbers remains a challenge. Herein, a novel and facile polymerization-induced assembly-etching strategy is proposed for the manufacture of wrinkled zeolitic imidazolate framework-67@polypyrrole (ZIF-67@PPy) microcages using ammonium persulfate catalyzed pyrrole polymerization and concomitant acid etching. Then, hollow cobalt@N-doped carbon microcages (Co@NCMs) with distorted carbon shells, rich core-shell heterojunctions, highly dispersive Co nanoparticles, and abundant heterogeneous interfaces are produced via high-temperature pyrolysis process, which eliminates the need for additional templates and etching agents. Moreover, the hollow microcage structure with interior cavities and mesopores provides superior impedance matching and lightweight characteristics to the absorbers. Therefore, the hollow absorbers demonstrate a minimum reflection loss of −50.4 dB and an effective absorption bandwidth (EAB) of 3.85 GHz at 2.7 mm with a 10 wt% filler loading. In general, the polymerization-indued assembly-etching strategy inspires the hollow engineering of MOF derivatives, and facilitates the development of superior electromagnetic wave absorption (EMA) materials.

Large-scale solution blow spinning of flexible carbon nanofibers for the separation applications

Massive production of carbon nanofibers with low thermal conductivity and excellent properties has remained as an extremely challenging. Herein, solution blow spinning technology and textile post-treating technic were introduced to achieve the mass production of carbon nanofibers and its derivative products. Different types of materials (polyacrylonitrile and lignin) were utilized as the spinnable agent and carbon source. A comprehensive investigation was conducted into the influences of raw material components, blow spinning process, and high-temperature pyrolysis process on the performance of carbon nanofibers. Through controlling the solution flow rate (10–50 mL·h−1), different needle diameters (21–25 G) and high pressure airflow (0.2–0.4 MPa), organic solution could be effectively spined into organic fiber precursor. Importantly, with the assistant of textile rearrange and needle punching technics, loose organic sponge can be transformed into blanket with designed thicknesses and shapes. These SBS spined carbon fiber products exhibited ideal compressional resilience ability (up to 60 %), adsorption of toluene, and thermal insulation performance (0.037 W·(m·K)-1).

Developing a parametric system model to describe the product distribution of steam pyrolysis in a Dual Fluidized bed

Steam pyrolysis is a thermochemical process that converts carbon-based materials into valuable gases. In general, the products of the reaction are syngas (H2,CO,CO2), low-molecular-weight hydrocarbon gases (methane, ethylene, and propylene), pyrolytic gasoline and oils, monoaromatic and polyaromatic species (tar), and carbonaceous residues (char) with ashes. However, the intricacy of the reactions comprising the process, the diversity of the product species, and the constraints linked to the sampling and measurement equipment, create a highly complex system. In this work, a method for data representation is presented based on a special Parametric System Model (PSM) that portrays product species measurements in a way that provides relevant information and valuable insights into the process. The method incorporates generic knowledge of the chemical nature of the reactions to create a constrained system in which the data can be expressed in parametric terms with meaningful statistical functions. The evaluated data were obtained from a high-temperature steam pyrolysis process performed in the 2–4-MW Dual Fluidized Bed reactor at Chalmers University using polyethylene as feedstock. The quantities of the hydrocarbon species detected in the gas product were taken for the PSM as a probabilistic system that can be described with a set of distribution functions. The carbon, hydrogen and oxygen balances were taken into account to build a constrained set of equations to find the parameters of the functions. The resulting model was proven to be useful as a prediction tool to quantify unmeasured carbon group species and to estimate process variables, such as the oxygen transport of the bed material. Also, it was demonstrated the potential of the model as a method to identify and estimate inconsistencies in the measurements, which improve the quality of the characterization data. The modeĺs outcomes find application in providing critical information for the control and evaluation of pyrolysis process and downstream operation of biorefineries.

Non-metal activated peroxydisulfate by straw biochar for tetracycline hydrochloride oxidative degradation: catalytic activity and mechanism.

In this study, stalk biochar (BC) was prepared by a high-temperature pyrolysis process and used as a non-metallic catalyst to activate peroxydisulfate (PDS) to degrade tetracycline hydrochloride (TCH). Various characterization results showed that BC had a hollow tubular structure, irregular folds, and important active sites such as oxygen-containing functional groups. Under the optimal reaction conditions, the degradation rate of TCH reached 98.1% within 120 min. In addition, the degradation performance was satisfactory and similar under acidic and near neutral pH, and higher temperature promoted the degradation of TCH. The SO4·-, ·OH, and 1O2 generated by PDS activation were reactive oxygen species (ROS), which degraded TCH through free radical/non-radical synergistic pathways. Quenching experiments proved that the generated SO4·- and ·OH might be the dominant reactive oxygen species (ROS) during the oxidative reaction. The research results will provide a theoretical basis for the application of PDS activated by non-metallic catalysts in the remediation of tetracycline antibiotics pollution.