Influence Of Pyrolysis Temperature Research Articles

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

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.

Influence of Pyrolysis Temperature on Biochar Produced from Lignin–Rich Biorefinery Residue

The biorefinery concept is growing rapidly for bio-based production of fuels and products, and steam explosion is by far the most applied pre-treatment technology allowing the delignification of lignocellulosic biomass. Within the bioethanol production process, pyrolysis of lignin-rich residue (LRR), for producing char to be used in a wide variety of applications, presents a viable way to recover materials and energy, helping to improve the sustainability of the whole production chain. In the present study, it is shown that yields, elemental composition and porosity characteristics of LLR-char are significantly different from those of char produced from alkali lignin. Both products yields and char composition were more similar to the typical values of woody and herbaceous biomasses. The chemical characterization of the chars’ organic matrices as well as the content of the main inorganic species suggest the opportunity to perform pyrolysis at low temperatures for producing high yields of chars suitable to be used as carbon sink or soil fertilizers. The BET values of the chars obtained at final temperatures in the range 500–700 °C seem to be promising for char-application processes involving surface phenomena (e.g., adsorption, catalyst support), thus encouraging further analyses of char-surface chemistry.

Influence of pyrolysis temperature on sludge biochar: the ecological risk assessment of heavy metals and the adsorption of Cd(II).

Pyrolysis of sludge to biochar can not only reduce the sludge volume, toxic organic compound, and pathogens, but also be applied as effective adsorbents. However, the immobilization of heavy metals in the sludge and the properties of the biochar greatly rely on the pyrolysis temperature. In this paper, municipal sludge biochar (SBC) was prepared from 400 to 1000°C. Pyrolysis immobilized heavy metals in sludge and the potential ecological risk of heavy metals significantly decreased to low level at temperature above 500°C. At 700°C, the adsorption capacity of Cd(II) reached a maximum (120.24mg·g-1). The Cd(II) adsorption fitted the Pseudo-second-order model, indicating the existence of chemical adsorption. The adsorption capacity increased along with the initial pH and slowed down after pH reached 5.5. The existence of coexisting cations (Ca2+ and Na+) and anions (SO42- and NO3-) displayed different degree of inhibitory action on Cd(II) adsorption. The SEM, XRD, FTIR, and XPS analysis of sludge biochar before and after adsorption revealed that there were CdCO3, CdSO4, Cd2SiO4, Cd3(PO4)2, and Cd9(PO4)6 appearing on the surface of sludge biochar, suggesting that the adsorption of Cd(II) by SBC included co-precipitation, ion exchange, coordination with π electrons, and complexation. It was confirmed that different properties formed by pyrolysis temperature made a difference in adsorption mechanism of sludge biochar.

Influence of pyrolysis temperature on biochar properties and Cr(VI) adsorption from water with groundnut shell biochars: Mechanistic approach

This study was envisaged to understand the effect of increasing pyrolysis temperature on the Cr(VI) removal potential of the groundnut shells derived biochars. The biochars were prepared at four different pyrolysis temperatures (350 °C, 450 °C, 550 °C, 650 °C) and were used unmodified to examine the adsorption potential for Cr(VI). Influence of biochar dose (1–10 g/L), pHinitial (2–10), Cr(VI)initial (10–500 mg/L) on Cr(VI) adsorptions; adsorption kinetics and isotherms were investigated. The observations suggested that the pyrolysis temperature is the key player in deciding the physicochemical properties as well the adsorption potential of the biochars. SEM and FTIR analysis suggested significant morphological and functional transformations in biochars with increasing pyrolysis temperature. The pHinitial was found to be the most profound adsorption parameter determining the adsorption potential of the biochars. The Cr(VI) adsorption capacity of the biochars decreased with the increase of the pyrolysis temperature (142.87–31.25 mg/L) as well as the solution pHinitial. All the biochars attained 100% removal efficiency with 50 mg/L of Cr(VI)initial and GNSB/350 achieved it in the minimum time (10 h) among all the biochars. GNSB/350 showed promising Langmuir adsorption capacity of 142.87 mg/L (pH 2, Tadsorption 30 °C, Cr(VI)initial 10–500 mg/L). In addition, the adsorption mechanism was found to be a synergistic action of chemi/physi-sorption with monolayer adsorption. Hence, the pyrolysis temperature significantly altered the physicochemical properties of the biochars, which highly influenced the adsorption performance of biochars.

Biochar and bio-oil fuel properties from nickel nanoparticles assisted pyrolysis of cassava peel

Direct biomass usage as a renewable fuel source and substitute for fossil fuels is discouraging due to high moisture, low energy density and low bulk density. Herein, thermogravimetric analysis (TGA) was conducted at various heating rates to determine peak decomposition temperatures for the dried cassava peels (DCP). The influence of pyrolysis temperature (300, 400, 500 and 600 °C) and heating rates (10, 20 and 30 °C/min) on the nickel nanoparticles catalyzed decomposition of DCP to produce biochar, bio-oil and biogas was investigated and characterized. The results revealed higher biochar (CBC) yield of 68.59 wt%, 62.55 wt% and 56.92 wt% at lower pyrolysis temperature of 300 °C for the different heating rates of 10, 20 and 30 °C/min. The higher carbon content of 52.39, 53.30 and 55.44 wt% was obtained at elevated temperature of 600 °C and heating rates of 10, 20 and 30 °C/min, respectively. At the pyrolysis temperature of 600 °C and heating rates of 10, 20 and 30 °C/min, the optimum yield of bio-oil (24.35, 17.69 and 18.16 wt%) and biogas (31.35, 42.03 and 46.12 wt%) were attained. A high heating value (HHV) of 28.70 MJ/kg was obtained for the biochar at 600 °C. Through the TGA, FTIR and HRSEM results, the thermal stability, hydrophobicity and structural changes of DCP and CBC samples were established. Similarly, the thermal stability of CBC samples increased with increasing pyrolysis temperature. Biochar with optimum fuel properties was produced at 600 °C due to the highest carbon content and high heating value (HHV). Improved kinematic viscosity (3.87 mm2/s) and density (0.850 g/cm3) were reported at the temperature of 300 °C and heating rate of 30 °C/min, while a higher pH (4.96), HHV (42.68 MJ/kg) and flash point (53.85 min) were presented by the bio-oil at the temperature of 600 °C and heating rate of 30 °C/min. Hence, DCP produced value-added biochar and bio-oil as renewable energy.

Pyrolysis Characteristics of Indonesian Oil Sand in a Fixed Bed.

In this research, pyrolysis experiment of Indonesian oil sand was performed in a fixed bed. Results show that the temperature and heating rate had significant effects on the pyrolysis products. Data studied include yields of products and the gaseous product composition of carbon monoxide, hydrogen, methane, and other hydrocarbons. Four functional group bands (aromatic hydrocarbon, oxygen, aliphatic, and hydroxyl functional groups) are observed from Fourier transform infrared spectroscopy of oil sand. The influence of pyrolysis temperature on the total pore volume and the Brunauer–Emmett–Teller (BET) specific surface area of char was also studied. With increasing temperature, the BET specific surface area showed an increasing trend in the overall temperature range. The specific surface area and the total pore volume showed similar trends except the tiny difference of 5 °C/min from 200 to 300 °C. The heating rate did not influence the development of the pore structure obviously. Mainly, three different reaction regions were observed during pyrolysis of oil sand. This study provides a theoretical foundation for further effective exploitation and economical application of oil sand.

Influence of pyrolysis temperature on rice straw biochar properties and corresponding effects on dynamic changes in bispyribac-sodium adsorption and leaching behavior in soil

Bispyribac-sodium is a weakly acidic herbicide with high water solubility and is thus a potential source of groundwater contamination. Considering the risk inherent to the use of this herbicide, this study assessed the impacts of rice straw (RS) and biochar amendments on the adsorption and leaching behavior of bispyribac-sodium in soil. Biochars were produced from RS at different pyrolysis temperatures and characterized using various spectral techniques. Rice straw had a surface area of 3.996 × 104 m2 kg–1, which increased under pyrolysis; biochars prepared at 350 and 550 °C (RS350 and RS550) in a closed furnace with limited oxygen supply had a surface area of 5.763 × 104 and 6.890 × 104 m2 kg–1, respectively, and biochar prepared by purging the pyroformer with N2 (RSC) had the highest surface area of 12.173 × 104 m2 kg–1. After amendment with RS and biochar, soil Freundlich adsorption capacity (KFads) increased to varying extents in the order RSC > RS350 > RS550, from 2.89 × 103 to 29.57 × 103 mg1–1/n kg–1 L1/n, compared to 1.55 × 103 mg1–1/n kg–1 L1/n in unamended soil. The variability in KFads of bispyribac-sodium amongst the RS- and biochar-amended soils was dependent on the surface area of the amendments. The desorption of bispyribac-sodium decreased in the RS- and biochar-amended soils and varied from 90.45% to 95.20% in unamended soils and from 60.95% to 89.50% in amended soils. The adsorption and desorption of bispyribac-sodium varied significantly depending on its concentration and the type and application rate of soil amendment. Different leaching risk evaluation indices, viz., modified leach index (M.LEACH), leach index (LEACH), groundwater ubiquity score (GUS), Hornsby index (HI), leaching index (LIN), and pesticide leaching potential (PLP) index, were used to assess the susceptibility of groundwater to herbicide leaching. To reduce the repetitive effects of common parameters in each index, a new index was developed by employing principal component analysis (PCA) to condense their information into a single ranking. The results of the PCA indicated that RS and biochar amendments could be an effective management practice for controlling the leaching potential of bispyribac-sodium in soil.

Catalytic pyrolysis of cellulose with sulfonated carbon catalyst to produce levoglucosenone

In this study, a new method for the efficient preparation of levoglucosenone (LGO) by biomass catalytic pyrolysis with sulfonated carbon catalyst was proposed. The influence of pyrolysis temperature and the mass ratio of catalyst to glucose or cellulose on the formation of LGO was systematically studied. The results show that when the mass ratio of glucose to sulfonated carbon is 1:1 and the pyrolysis temperature increases from 300 °C to 500 °C, the LGO selectivity first increased and then decreased, reaching a maximum value of 46.4% at 400 °C. Meanwhile, the yield of LGO increased steadily with the increase in pyrolysis temperature, and the yield of LGO was reached a maximum value of 2.48 wt% at 500 °C. However, with the increasing amount of catalyst, the selectivity of LGO increased steadily, while the yield of LGO increased at first and then decreased. Overall, the optimum pyrolysis temperature and mass ratio of the glucose/sulfonated carbon catalyst for LGO production were 400 °C and 1:1, respectively. Density functional theory calculations showed that the catalytic action of sulfonated carbon changed the reaction pathway of glucose pyrolysis, making glucose more inclined to form LGO through a 1,2 dehydration mechanism.