Influence Of Pyrolysis Temperature Research Articles

Spent Coffee Ground Biochar for phosphate adsorption in water: Influence of pyrolysis temperature and iron-coating activation method

Spent Coffee Ground Biochar for phosphate adsorption in water: Influence of pyrolysis temperature and iron-coating activation method

A Thermogravimetric Analysis of Biomass Conversion to Biochar: Experimental and Kinetic Modeling

This study investigates the pyrolytic decomposition of apple and potato peel waste using thermogravimetric analysis (TGA). In addition, using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), the influence of pyrolysis temperature on the physicochemical characteristics and structural properties of biochar was studied. The degradation of biomass samples was studied between 25 °C and 800 °C. Although apple and potato peel decomposition present similar thermogravimetric profiles, there are some differences that can be evidenced from DTG curves. Potato peel showed one degradation peak in the range 205–375 °C with 50% weight loss; meanwhile, the apple peel exhibited two stages: one with a maximum at around 220 °C and about 38% weight loss caused by degradation of simple carbohydrates and a second peak between 280 °C and 380 °C with a maximum at 330 °C, having a weight loss of approximately 24%, attributed to cellulose degradation. To gain more insight into the phenomena involved in biomass conversion, the kinetics of the reaction were analyzed using thermal data collected in non-isothermal conditions with a constant heating rate of 5, 10, 20, or 30 °C /min. The kinetic analysis for each decomposed biomass (apple and potato) was carried out based on single-step and multi-step type techniques by combining the Arrhenius form of the decomposition rate constant with the mass action law. The multi-step approaches provided further insight into the degradation mechanisms for the whole range of the decomposition temperatures. The effect of temperature on biomass waste structure showed that the surface morphologies and surface functional groups of both samples are influenced by the pyrolysis temperature. A higher pyrolysis temperature of 800 °C results in the disappearance of the bands characteristic of the hydroxyl, aliphatic, ether, and ester functional groups, characteristic of a porous surface with increased adsorption capacity. Therefore, this study concludes that biomass waste samples (apple and potato) can produce high yields of biochar and are a potential ecological basis for a sustainable approach. The preliminary adsorption tests show a reasonably good nitrate removal capacity for our biochar samples.

Influence of pyrolysis temperature on biochar properties: Applications as a reinforcing filler in sbr and epdm elastomeric compounds

This study investigates the effect of pyrolysis temperature on the properties of biochar derived from Pinus spp. wood waste and its application as a reinforcing filler in styrene-butadiene rubber (SBR) and ethylene-propylene-diene monomer (EPDM) elastomeric compounds. Biochar was produced at 400°C and 900°C and its effects on the mechanical properties of the elastomers were analyzed. The results indicate that biochar produced at 900°C has higher fixed carbon content and lower volatile matter, resulting in improved mechanical properties such as tensile strength and elongation at break compared to biochar produced at 400°C. Despite a lower specific surface area, the irregular surface structure of biochar enhances its interaction with elastomers, providing a semi-reinforcement. This study highlights the potential of high-temperature biochar as a sustainable alternative to conventional fillers such as carbon black, contributing to the development of environmentally friendly materials from biomass waste. The results support further exploration of the role of biochar in elastomer applications, highlighting its environmental and mechanical benefits.

The Influence of Pyrolysis Temperature and Feedstocks on the Characteristics of Biochar-Derived Dissolved Organic Matter: A Systematic Assessment

Biochar is a carbon-rich product obtained by pyrolyzing biomass under oxygen-limited conditions and has a wide range of potential for environmental applications. In particular, dissolved organic matter (DOM) released from biochar has an important impact on the fate of pollutants. The study aimed to systematically assess how varying pyrolysis temperatures and biomass feedstocks influence the characteristics of biochar-derived DOM. DOM samples were comprehensively characterized utilizing UV-vis spectroscopy and excitation–emission matrix (EEM) fluorescence spectroscopy, coupled with parallel factor (PARAFAC) analysis. The study discovered that pyrolysis temperature significantly affects DOM characteristics more than feedstock type. An increase in pyrolysis temperature correlated with a notable decrease in dissolved organic carbon content, aromaticity, and fluorescence intensity, alongside a marked increase in pH and hydrophilicity. PARAFAC analysis identified three distinct DOM components: two humic-like substances (C1 and C2) and one protein-like substance (C3). The proportion of protein-like substances increased with higher pyrolysis temperatures, while the humic-like substances’ proportion declined. The compositional shifts in DOM with pyrolysis temperature may significantly influence its environmental behavior and functionality. Further research is necessary to explore the long-term environmental impact and potential applications of biochar-derived DOM.

The impact of water hyacinth biochar on maize growth and soil properties: The influence of pyrolysis temperature

AbstractIntroductionOptions for managing water hyacinths (WHs) include converting the biomass into biochar for soil amendment. However, less has been known about the impact of WH‐based biochar developed in varying pyrolysis temperatures on plant growth and soil qualities.Materials and MethodsA pot experiment was undertaken in a factorial combination of WH biochars (WHBs) developed at three temperatures (350°C, 550°C and 750°C) and two application rates (5 and 20 t ha−1), plus a control without biochar. Maize was grown as a test crop for 2 months under natural conditions.ResultsOur study showed that applying WHB developed between 350°C and 750°C at 20 t ha−1 increased maize shoot and root dry biomass by 47.7% to 17.6% and 78.4% to 54.1%, respectively. Nevertheless, raising the biochar pyrolysis temperature decreased maize growth, whereas increasing the application rate displayed a positive effect. The application of WHB generated at 350°C and 550°C at 20 t ha−1 resulted in significant improvements in soil total nitrogen (17.9% to 25%), cation exchange capacity (27.3% to 20.2%), and ammonium‐nitrogen (60.7% to 59.6%), respectively, over the control. Additionally, applying WHB produced from 350°C to 750°C at 20 t ha−1 enhanced soil carbon by 38.5%–56.3%, compared to the control. Conversely, applying biochar produced at 750°C resulted in higher soil pH (6.3 ± 0.103), electrical conductivity (0.23 ± 0.01 dS m−1) and available phosphorus (21.8 ± 2.53 mg kg−1).ConclusionWHBs developed at temperatures of 350°C and 550°C with an application rate of 20 t ha−1 were found to be optimal for growing maize and improving soil characteristics. Our study concludes that pyrolysis temperature significantly governs the effectiveness of biochar produced from a specific biomass source.

3D carbonaceous substrates synthesized from melamine sponges for energy storage: Influence of pyrolysis temperature in physicochemical and electrochemical properties

High-energy global requirements have caused a renewed interest in studying and developing new and improved energy storage devices and, precisely, the electrode materials that compose them, which play a fundamental role in determining the device’s performance. Carbon materials are first-class candidates due to their high electrical conductivity, chemical stability, and surface area. Although several carbon materials and their precursors have been studied, melamine sponges stand out for their nitrogen content, allowing them to act as a template and precursor for N-doped, ultralight carbon materials with good mechanical properties and a controlled pore size distribution. This work reports a simple and quick methodology to form ultralight and flexible carbon foam, along with the influence of the pyrolysis temperature on the physicochemical and electrochemical properties of 3D carbonaceous substrates used for energy storage and synthesized from melamine sponges. The substrates exhibit higher 3D porous structure than previously reported materials, with an average pore diameter of 80–90 µm. This morphology, added to the N content, promotes the remarkable electrochemical behavior (MS–950 °C) and cycling stability (MS–1000 °C) of almost 100% of capacitance retention after 10,000 cycles (≈ 60 F/g @1 A/g).

Influence of pyrolysis temperature on carbon deposition from the perspective of volatile evolution during the ex-situ pyrolysis-catalysis of plastic

To better understand the mechanism of carbon deposition, the ex-situ catalytic pyrolysis of polyethylene (PE) was explored over a FeNi/Al2O3 catalyst, and the evolution of volatiles as well as the yield and structure of carbon products at different temperatures were analyzed in depth by an in-situ atmospheric pressure photoionization high-resolution mass spectrometry (APPI HRMS) combined with a fixed-bed reactor. The results show that raising the pyrolysis temperature (from 500 to 800 °C) reduces carbon product yield and H2 production, and the proportion of carbon nanotubes (CNTs) in the carbon products decreases. The source of carbon products gradually shifts from liquid-phase carbon sources to gaseous-phase carbon sources. Below 700 °C, both the outer diameter and carbon interlayer spacing of CNTs decrease, while above 700 °C, they both increase along with increased distortion of carbon layers. It is also observed that the carbon layers are connected to the catalyst lattice stripes, and the interlayer spacing of carbon layers is greater than the catalyst lattice spacing. In situ mass spectrometry reveals a significant increase in the carbon number and double bond equivalent (DBE) values of volatiles with increasing pyrolysis temperature, but the rate of increase slows down after 700 °C. Volatiles from lower pyrolysis temperatures undergo severe polymerization, upon entering the catalytic zone at higher temperatures, minimizing temperature-induced distinctions. Nevertheless, it remains evident that volatiles from lower pyrolysis temperatures exhibit less pronounced polymerization when exposed to higher catalytic temperatures.

Application of corn stover derived pyrolyzed hydrochars for efficient phosphorus removal from water: Influence of pyrolysis temperature

Excessive phosphorus load to surface water is undesirable since it can cause eutrophication. In this study, three different pyrolyzed hydrochars from corn stover were synthesized by applying hydrothermal carbonization (HTC) at 260 °C and then eventual pyrolysis at 400°, 600°, and 800 °C, respectively, and finally were used for phosphorus removal from aqueous solution. By linking the physicochemical properties of these pyrolyzed hydrochars investigated here, we tried to comprehend the effect of HTC and pyrolysis temperature on the hydrochar structure and phosphorus adsorption. Results show that high pyrolysis temperatures (600 °C and 800 °C) enhanced the hydrochar's phosphorus adsorption compared to low pyrolysis temperature (400 °C). HTC260P800 type hydrochar showed a fast phosphorus adsorption kinetics, while the HTC260P600 showed an overall high adsorption capacity, with the maximum phosphate adsorption capacity of 5090 mg/kg calculated using isotherm model. Three different adsorption isotherm models (Langmuir, Fruendlich, and Redlich-Peterson) were used to fit the isotherm data; among them, the Redlich-Peterson isotherm model fit the data best for all three hydrochars. pH was found to be a critical factor in terms of phosphorus removal, and the optimum pH was found to be 5, probably due to the enhanced electrostatic interaction between positively charged hydrochar and negatively charged phosphate ions. The desorption experiment showed that a small fraction of the adsorbed phosphate (15.6 % to 24.4 %) was released from the spent hydrochar samples, which might be due to the strong attachment of phosphate ions to the sorption sites. Reusing the spent pyrolyzed hydrochar showed lower phosphate adsorption capacity than the fresh ones, ranging from 423 mg/kg to 903 mg/kg.

Application of machine learning in prediction of Pb2+ adsorption of biochar prepared by tube furnace and fluidized bed.

Data mining by machine learning (ML) has recently come into application in heavy metals purification from wastewater, especially in exploring lead removal by biochar that prepared using tube furnace (TF-C) and fluidized bed (FB-C) pyrolysis methods. In this study, six ML models including Random Forest Regression (RFR), Gradient Boosting Regression (GBR), Support Vector Regression (SVR), Kernel Ridge Regression (KRR), Extreme Gradient Boosting (XGB), and Light Gradient Boosting Machine (LGBM) were employed to predict lead adsorption based on a dataset of 1012 adsorption experiments, comprising 422 TF-C groups from our experiments and 590 FB-C groups from literatures. The XGB model showed superior accuracy and predictive performance for adsorption, achieving R2 values for TF-C (0.992) and FB-C (0.981), respectively. Contrasting inferior results were observed in other models, including RF (0.962 and 0.961), GBR (0.987 and 0.975), SVR (0.839 and 0.763), KRR (0.817 and 0.881), and LGBM (0.975 and 0.868). Additionally, a hybrid dataset combining both biochars in Pb adsorption also indicated high accuracy (0.972) as obtained from XGB model. The investigation revealed that the influence of char characteristics and adsorption conditions on Pb adsorption differs between the two biochar. Specific char characteristics, particularly nitrogen content, significantly influence lead adsorption in both biochar. Interestingly, the influence of pyrolysis temperature (PT) on lead adsorption is found to be greater for TF-C than for FB-C. Consequently, careful consideration of PT is crucial when preparing TF-C biochar. These findings offer practical guidance for optimizing biochar preparation conditions during heavy metal removal from wastewater.

Evaluation on thermal pyrolysis of biomass straw waste: Focusing aspects of products yields, syngas emissions and solid products characterization

AbstractIn this study, a systematic and quantitative investigation of the pyrolysis characteristics of biomass was conducted in a fixed‐bed tubular reactor, and the influence of pyrolysis temperature on product yields, gas emission characteristics, and syngas compositions as well as physicochemical characterization of resulting solids (i.e., char/ash morphologies, mineral transformations, and elemental compositions) was explored in detail. The pyrolysis experiments were performed under N2, and the resulting solid characterization was detected by XRD, SEM, and EDX. The results indicated that with increasing the pyrolysis temperature from 400 to 800°C, the gaseous product yields increased from 54.9% to 66.7%, while the solid product yield showed a reverse trend, varying within 27.7%–40.5%. Meanwhile, the volume fraction of H2 in syngas increased from 7% to 33%, while the CO2 presented an opposite trend, suggesting that high temperature favored H2 formation and inhibited CO2 formation. On the whole, the CO and CO2 emissions were prior to CH4, H2, and CnHm in sequence. A large amount of sylvite (KCl), quartz (SiO2), dolomite (CaMg(CO3)2), and pyroxene (CaMgSi2O6) in the resulting solids were identified in crystal phases. Higher pyrolysis temperature had a significant influence on solid microstructures, resulting in a relatively higher slagging tendency due to low melting eutectics containing K‐rich and Ca‐rich minerals.

The Influence of Pyrolysis Temperature on the Performance of Cotton Stalk Biochar for Hexavalent Chromium Removal from Wastewater

The Influence of Pyrolysis Temperature on the Performance of Cotton Stalk Biochar for Hexavalent Chromium Removal from Wastewater

Enhanced toluene removal from aqueous solutions using reed straw-derived biochar

Abstract The escalating threat of pollutants, particularly aromatic hydrocarbons like benzene, toluene, ethylbenzene and xylene (BTEX), in aquatic environments necessitates effective remediation strategies. This study explores the potential of biochar derived from common reed (Phragmites australis) as a sustainable and multifaceted tool for the removal of toluene, a representative BTEX compound, from aqueous solutions. By harnessing reed straw as the precursor material for biochar production, this research showcases an environmentally friendly alternative to conventional disposal methods, such as incineration, offering the dual benefit of pollutant removal and carbon emissions reduction. The influence of pyrolysis temperature on biochar properties and its adsorption efficiency for toluene were rigorously examined, revealing a direct correlation between temperature and biochar’s pollutant sequestration capabilities. Results indicate that higher pyrolysis temperatures led to biochar (RB-750) with superior specific surface area (68.07 m2/g) and enhanced adsorption capabilities, demonstrating its potential as a powerful adsorbent in water treatment. The scanning electron microscope analysis revealed a complex, porous structure rich in active sites, validating the biochar’s suitability for pollutant adsorption. Optimal dosage was determined at 8 g/l, achieving an impressive toluene removal efficiency of 98.1%. Additionally, pH and initial toluene concentration significantly influenced removal efficiency. This study underscores the multifaceted potential of reed straw-derived biochar in combating water pollution while concurrently contributing to carbon emissions reduction through sustainable utilization of abundant wetland resources. Further research should delve into the impact of real-world conditions on its effectiveness, promising innovative solutions for environmental remediation efforts with a reduced carbon footprint.

Triboelectric nanogenerator based on reactivated electrode materials derived from waste alkaline battery: Influence of pyrolysis temperature and surface morphology

Triboelectric nanogenerators (TENGs) have been extensively studied in recent years due to their potential for energy harvesting and self-powered sensing. However, most of the research has focused on only exploring new materials, while there has been limited examination of how optimizing material properties or device system designs could enhance the TENG devices' performance. To address this gap, this research presents a pioneering approach using thermally reactivated electrode materials derived from waste alkaline batteries (WABs) for future energy harvesting applications in TENGs. By systematically investigating how the oxygen content and surface morphology affect TENG device performance at different pyrolysis temperatures, we achieved optimal TENG material at 500 °C, exhibiting outstanding output voltage, current, and power density of 790 V, 40.27 µA, and 529.375 µW/cm2, respectively. Mechanical stability testing revealed that the TENG device based on RC-WABs remains stable for over 40,000 cycles with consistent output performance. Furthermore, the proposed method employs a simple and efficient pyrolysis technique to reactivate the cathode and anode materials of WABs, operating at low temperatures without activating gases or inert atmospheres. To validate real-time applicability, the TENG device was successfully employed to power various applications, such as illuminating 150 LEDs and operating a digital calculator. This research provides a new perspective on the use of waste materials for energy harvesting applications and offers a potential solution for recycling waste alkaline batteries, which is one of the significant environmental problems. Overall, the findings highlight the potential of the proposed approach for future TENG device design and provide a new direction for sustainable energy harvesting.

Influence of Pyrolysis Temperature and Time on Biochar Properties and Its Potential for Climate Change Mitigation

The thermochemical conversion of disposable bamboo chopstick (DBC) wastes into biochar is a practical strategy for converting waste into resources. This study aimed to investigate the effects of pyrolysis temperature and holding time on the physicochemical properties of DBC biochar and its potential for climate change mitigation. Properties affecting the biochar efficiency and potential for application were analyzed: moisture content (MC), volatile matter (VM), fixed carbon (FC), ash, pH, and carbon (C), hydrogen (H), nitrogen (N), and oxygen (O) content. Six different pyrolysis conditions were studied, with temperatures of 400 °C, 450 °C, and 500 °C and holding times of 20 and 60 min, at a constant heating rate. The results demonstrated that temperature and holding time significantly affected the physicochemical properties and performance of the biochar. Increases in %C, %FC, %N, and pH and reductions in %MC, %VM, %H, and %O were found when the temperature was increased at different holding times. The aromaticity increased and the polarity decreased significantly with increasing temperature and holding time. The results showed that temperature interacts significantly with holding time, and these two factors jointly affect the contents of MC, ash, FC, C, H, N, and O (R2 of 0.997) and pH (R2of 0.999). The DBC biochar obtained via pyrolysis at 450 °C and 500 °C for 20 and 60 min could be applied for climate change mitigation. The best DBC biochar was obtained at a pyrolysis temperature of 500 °C and a holding time of 20 min. This biochar showed good hydrophobicity, tremendous stability, the highest C (88.06%) and FC (76.49%) values, and the lowest ash (2.62%) and VM (19.23%) contents. Doi: 10.28991/HEF-2023-04-04-07 Full Text: PDF

Investigation on Pb2+ adsorption characteristics by AAEMs-rich biochar in aqueous solution: Performance and mechanism

Biochar derived from soybean straw with AAEMs (alkali and alkaline earth metals) enrichment could efficiently remove heavy metals from contaminated water. In this study, the influences of pyrolysis temperature on the physicochemical property and adsorption performance of soybean straw biochar were investigated. The contributions of different adsorption mechanisms were analyzed quantitatively. The results show that the soybean straw biochar exhibits excellent Pb2+ adsorption performance (157.2–227.2 mg g−1), with an order of BC800 > BC400 > BC600 > BC700 > BC500. The mechanisms of metal ion exchange (37.49%–72.58%) and precipitation with minerals (22.38%–58.03%) mainly control the Pb2+ adsorption, whereas complexation with organic functional groups (OFGs) and cation-Cπ interaction make the less contribution. The order of cation exchange capacity (CEC) is BC400 > BC800 > BC700 > BC600 > BC500, showing a high correlation (0.965) with the contribution of metal ion exchange with AAEMs. Moreover, Ca exhibits the strongest exchange capacity. The contribution of precipitation is consistent with the variation of soluble CO32− content in biochar. These results suggest that soybean straw biochar rich in AAEMs is a prospective adsorbent for Pb2+ elimination.

Adsorbent biochar derived from corn stalk core for highly efficient removal of bisphenol A.

Environmental-friendly biochar (BC) with low cost was obtained by simple pyrolysis of corn stalk core, which was employed as an adsorbent for efficiently removing organic pollutants in water. The physicochemical properties of BCs were characterized by various techniques, including X-ray diffractometer (XRD), Fourier transforms infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectrometer (XPS), Raman, Thermogravimetric (TGA), N2 adsorption-desorption and zeta potential tests. The influence of pyrolysis temperature on the structure and adsorption efficiency of the adsorbent was emphasized. The graphitization degree and sp2 carbon content of BCs were enhanced by increasing the pyrolysis temperature, which was favorable for the enhancement of the adsorption efficiency. The adsorption results showed that corn stalk core calcined at 900°C (BC-900) displayed exceptional adsorption efficiency toward bisphenol A (BPA) in wide pH (1-13) and temperature (0-90°C) ranges. Moreover, adsorbent BC-900 could adsorb various pollutants from water, including antibiotics, organic dyes, and phenol (50mg·L-1). The adsorption process of BPA over BC-900 matched well with the Langmuir isotherm and pseudo-second-order kinetic model. Mechanism investigation suggested that large specific surface area and pore filling acted the foremost role in the adsorption process. Adsorbent BC-900 has the potential application in wastewater treatment due to its simple preparation, low cost, and excellent adsorption efficiency.

Study of the activity and stability of sulfonated carbon catalyst from agroindustrial waste in biodiesel production: Influence of pyrolysis temperature on functionalization

The influence of pyrolysis temperature on the activity and catalytic stability of sulfonated biochar, from the agro-industrial residue murumuru kernel shell, was evaluated in the esterification reaction. Carbonaceous materials were synthesized by direct pyrolysis at 450, 600 and 750 °C and functionalized with sulfuric acid at 200 °C for a 4 h period. The materials were characterized by density of sulfonic groups, SEM, EDS, Elementary Analysis, ATR-FTIR, Raman Spectroscopy, TG and XPS analysis. The data obtained showed that the functionalization occurred directly in the carbon chain of biochar, evidencing that higher carbonization temperatures resulted in carbonaceous catalysts of more stable polycondensed nature. The catalyst synthesized at 750 °C achieved conversion of 98.35% ± 1.105 and maintained in the third reaction cycle conversion of 89.35% ± 1.197. This catalyst also showed the highest content of sulfur groups, even after reuse processes. The increment of temperature and time in the reaction medium was able to improve the reuse capacity of relatively low stability catalysts. Thus, the results obtained show the impact of pyrolysis temperature on obtaining catalysts with greater activity and catalytic stability in esterification reactions, and in this way provide very important subsidies for the development of new heterogeneous sulfonated carbon-based catalysts, applied in the biodiesel production process.

Influence of Oyster Shell Pyrolysis Temperature on Sediment Permeability and Remediation

Permeability is an important aspect of sediment remediation. It is well-known that oyster shells can be used for sediment remediation, however the influence of pyrolysis temperature on sediment permeability remains unknown. In this study, we examined sediment permeability and remediation using crushed oyster shells of less than 5 mm in size that were pyrolyzed at 350 °C (POS350) and 600 °C (POS600) for six hours. Based on the results of the variable head permeability test, POS600 has greater sediment permeability than POS350. In addition, POS600 has greater than POS350 to reduce dissolved inorganic nitrogen (DIN; NH3-N, NO2-N, and NO3-N) and phosphate (PO4-P) from organically enriched sediment because of its higher Ca2+ elution. In conclusion, pyrolysis of oyster shells at 600 °C is more effective than pyrolysis at 350 °C. This finding is true because the transformation of CaCO3 to CaO, which is the source of Ca2+, stimulates pore water flow. Based on these findings, it can be concluded that pyrolyzed oyster shells are beneficial for increasing sediment permeability, thereby helping in the remediation of sediments.

Influence of pyrolysis temperature on the physicochemical properties of biochars obtained from herbaceous and woody plants

This work aimed to investigate the effect of pyrolysis temperature on the yield and properties of biochars synthesized from herbaceous and woody plants. Four typical materials, including two herbaceous plants (rice straw, corn straw) and two woody plants (camellia oleifera shells, garden waste), were used in the experiments under five operating temperatures (from 300 °C to 700 °C, with an interval of 100 °C). The results showed biochar derived from herbaceous plants had a significantly higher pH (from 7.68 to 11.29 for RS), electrical conductivity (EC, from 6.5 Ms cm−1 to 13.2 mS cm−1 for RS), cation exchange conductivity (CEC, from 27.81 cmol kg−1 to 21.69 cmol kg−1 for RS), and ash content (from 21.79% to 32.71% for RS) than the biochar from woody plants, but the volatile matter (VM, from 42.23% to 11.77% for OT) and specific surface area (BET, from 2.88 m2 g−1 to 301.67 m2 g−1 for OT) in the woody plant-derived biochar were higher. Except for CEC and VM, all the previously referred physicochemical characteristics in the as-prepared biochars increased with the increasing pyrolysis temperature, the H/C and O/C values of herbaceous and woody plant-derived biochar were lower than 0.9 and 0.3, respectively, confirming their potential as the material for carbon sequestration. The results revealed that biochar made from herbaceous plants was more suitable for acidic soil amendments. In contrast, woody plant-derived biochar were recommended to remove heavy metals in environmental remediation and water treatment.Graphical

A novel carbonized derivative of Fe-Cu bimetallic organic framework (Fe-Cu-MOF@C): preparation and optimization.

A carbon derivative with Fe-Cu bimetallic organic framework (Fe-Cu-MOF@C) was prepared by microwave synthesis and pyrolysis. Using potassium persulfate (PS) as oxidant and 2,4-dichlorophenol (2,4-DCP) as target pollutant, the optimal preparation conditions of Fe-Cu-MOF@C were studied. The factors affecting the synthesis of Fe-Cu-MOF include microwave power, microwave time, microwave temperature, the molar ratio of metal ions to organic ligands, the molar ratio of iron and copper, etc. In addition, the influence of pyrolysis temperature on the performance of Fe-Cu-MOF@C cannot be ignored. The results show that Fe-Cu-MOF@C has the best catalytic performance when the microwave time is 30 min, the microwave power is 600 W, the microwave temperature is 150 °C, the molar ratio of (Fe2+ + Cu2+)/H2BDC is 10:3, the molar ratio of Fe2+/Cu2+ is 10:1, and the pyrolysis temperature is 700 °C. After 90 min of reaction, 2,4-DCP was completely removed. Repeatable experiments show that Fe-Cu-MOF@C has good stability and its service life can be restored by heat treatment. In this study, a heterogeneous catalyst with strong catalytic capacity, high stability and easy recovery was prepared by a simple and efficient process, which is conducive to the development of advanced oxidation technology and the progress of water environmental protection.