Pyrolysis Time Research Articles

Elevating Sustainability and Profitability: Non-Precious Metal Nano Catalysts for Maximizing Yield and Calorific Value in Asphalt Pyrolysis

Pyrolysis has proven to be a promising method for converting complex organic materials such as asphalt into high-value products. In an effort to increase the economic efficiency of this process, we investigated the use of non-precious metal nano catalysts for asphalt pyrolysis. Non-precious metal nano catalysts were chosen because of their potential to increase reaction rates and optimize product yields. This research involves the preparation of non-precious metal nano catalysts and their implementation in the asphalt pyrolysis process. The temperature and pyrolysis time variables are varied to determine optimal conditions. The results showed that the use of non-precious metal nano catalysts resulted in a significant increase in the yield of pyrolysis products, with the highest yield reaching 50.78%. In addition, the calorific value of the resulting product also increased to 10684 calories per gram. The main advantage of this research is the emphasis on economic aspects. The use of non-precious metal nano catalysts effectively increases the efficiency of the pyrolysis process, leading to higher product yields and greater calorific values. Thus, the use of non-precious metal nano catalysts makes a positive contribution in reducing production costs on an industrial scale. These findings provide new insights in the development of pyrolysis technology that is sustainable and economical and encourages a wiser use of natural resources through the use of bitumen and other complex organic materials.

Efeito da aplicação do biochar na mobilidade do corante têxtil vermelho drimaren em uma camada de solo aluvionar

ABSTRACT The region of Alto Capibaribe, in the Brazilian semiarid, faces an environmental issue due to contamination from textile activities. Inadequate release of dyes and other toxic substances threatens human health and water resources, such as alluvial reserves. Thus, biochar, a low-cost adsorbent produced by biomass pyrolysis, helps mitigate these problems by increasing soil retention capacity. This study analyzed the effect of applying biochar, produced from coffee husks, a biomass already established in biochar production, at temperature of 530 °C with a pyrolysis time of 10 to 12 hours, in a homemade metallic furnace, resulting in a product with 67.11% carbon. This biochar was applied to evaluate the mobility of the textile dye Red Drimaren, at a concentration of 25 mg.L-1, used for garment dyeing in local industries, in a subsurface layer of an alluvial deposit located in the dry bed of the Capibaribe River. Fourier Transform Infrared Spectroscopy (FTIR) showed that the highest spectral vibrations are in the range of 1400-1800 cm-1, indicating the presence of amine and amide functional groups, favoring the biosorption process. The pH in water is higher than in KCl for all situations, with biochar being basic and the alluvial soil being acidic. The zero charge point values are equal to 6.96 and 7.96 for the proportions Soil+0.25%BC and Soil+1.00%BC, respectively. Layers with 0.25%BC and 1.00%BC added had an increase in adsorptive capacity of 31.68% and 8.62%, respectively, compared to the natural soil sorption capacity. Kinetic data best fit the pseudo-second-order model, and intra-particle diffusion was not the determining mass transfer process nor the occurrence of the adsorption process. Linear and Freundlich isotherm models consistently described the process under varying concentrations, and the Langmuir model did not show a valid physical significance.

Investigating the Optimization of Magnetic Biochar Production from Rubber Seed Shells for Enhanced Cr(VI) Removal Efficiency

This study aimed to utilize agricultural and produce low-cost magnetic biochar from rubber-seed shells using ferric chloride (FeCl3) as a transition metal. The study employs Response Surface Methodology (RSM) based on the Box-Behnken Design (BBD) to determine optimal production conditions for removing chromium (Cr(VI)). The effect of preparation conditions such as pyrolysis temperature (500-700 °C), duration (90-180 min), and impregnation (1-3 M) on the produced magnetic biochar was examined. The optimal condition was demonstrated based on yield percentage and Cr(VI) removal efficiencies. The study revealed that the optimal conditions for producing magnetic biochar from rubber seed shells were a pyrolysis temperature of 580 °C, a pyrolysis time of 130 min, and a FeCl3 concentration of 3 M. Under these conditions, a yield of 48.63% was achieved, and the removal efficiencies for Cr(VI) were 41.29%. This research suggests that utilizing agricultural waste products from rubber seed shells may be a viable and economical method for producing magnetic biochar, which can serve as an efficient adsorption agent.

PYROLYSIS OF SOYBEAN WASTE: A ROUTE TO BIOCARBON FOR PESTICIDES CAPTURE

Background: This study explores the potential use of biomass residues from soybean pressing via static pyrolysis to produce carbonaceous materials for pesticide adsorption. It emphasizes concerns regarding the environmental impact of agroindustrial waste and the persistent nature of pesticides in soil and water systems. Aims: To investigate the efficacy of biochar obtained from soybean waste in adsorbing pesticides. Specifically, to analyze the gas products generated during pyrolysis and characterize the obtained carbonaceous material for its adsorption capabilities. Methods: Soybean residue underwent static pyrolysis at various temperatures and durations. Gas analysis utilizing FTIR spectroscopy identified the gaseous products generated during the pyrolysis process. The obtained biochar underwent successive washes and characterization through FTIR spectra comparison with commercial activated carbon. Through absorption assays, using UV-VIS spectroscopy, investigations were conducted on the solid biocarbon fractions to evaluate their capacity for absorbing pesticides. Results: Gas Analysis: The study revealed the production of volatile organic compounds (VOCs) and highlighted the prevalence of mono-carbon compounds with increased temperature and pyrolysis time. The analysis demonstrated consistent carbon mass percentages across different reaction conditions. Characterization of Biochar: Comparison with activated carbon indicated structural similarities with heightened intensity in certain bands, suggesting the presence of incomplete cellulose cracking in the obtained biochar. Regarding the Chlorothalonil, Atrazine and DIcamba remotion, notably, the concentration of Chlorothalonil in a 7:3 water: acetonitrile solution decreases by 77 % through adsorption on the carbons. Discussion: The investigation examined the adsorption efficiency of the biochar for Chlorothalonil, Atrazine, and Dicamba from aqueous solutions. Chlorothalonil exhibited substantial retention by the biochar, while Atrazine showed comparatively lower adsorption effectiveness. Remarkably, Dicamba did not demonstrate retention by either the biochar or activated carbon. Conclusion: The study underscores the potential of pyrolyzed soybean waste for pesticide adsorption, particularly highlighting Chlorothalonil's strong affinity with the carbonaceous structure. Further research is needed to optimize adsorption properties and explores potential enhancements of these materials through additional treatment methods, offering promising avenues for environmental remediation.

Simultaneous removal of brominated and chlorinated species during the production of oils by e-waste plastics catalytic hydropyrolysis

The production of added-value chemicals via pyrolysis of plastic wastes, such as those from electrical and electronic equipment (WEEE), needs addressing their usual contamination with halogens (mainly Br and Cl). This work compares the conversion via pyrolysis and hydropyrolysis of a real WEEE plastic, having a complex composition, in two different reactor configurations: down-flow (DF) and up-flow (UF). Likewise, the effects of incorporating a Pd/Al2O3 catalyst and using two different pressures (1 and 6 bar) have been assessed. With the DF mode, pyrolysis at 1 bar leads to an oil yield above 80 wt% and a total halogen content of about 600 ppm (vs 1600 ppm in the water-washed WEEE plastic). Under DF catalytic hydropyrolysis at 6 bar, this high oil yield is maintained while its dehalogenation degree is improved (142 ppm). Operating with the up-flow configuration, under 6 bar and H2 presence, leads to some reduction in the oil yield (about 70 wt%) but significantly decreases the oil halogen content (55 ppm Cl and total elimination of Br). These results have been related to the slower pyrolysis and longer residence time in the thermal zone of the UF configuration, which favours the halogen-trapping effect of the char fraction, and the pressure-enhanced hydrodehalogenation activity of the catalyst. This study highlights the environmental benefits of the proposed process, emphasizing the lower halogen content in the resulting oils and promoting a more sustainable approach to plastic waste valorisation.

Hydroformylation of 1‐butene to N‐pentanal on Co‐based Materials Derived from ZIF‐67: Optimization of Pyrolysis Conditions and DFT Study

AbstractWe prepared the Co‐based materials via the pyrolysis of ZIF‐67 at low temperature (250 °C~350 °C), and obtained the optimum catalyst ZIF‐67‐Sg‐350‐10 with the conversion of 1‐butene, aldehyde selectivity and n/i ratio of 94.9 %, 77.1 % and 2.2, respectively. The conversion of 1‐butene and aldehyde selectivity obviously increased with the increasing pyrolysis temperature and pyrolysis time. It was found that the interaction between the Co cluster and N‐doped carbon composites could improve the hydroformylation activity. Different catalyst models were built to investigate the active centers (Co) in the derived materials. The Co‐N4 surface was the best catalyst model with the lowest hydrogen insertion reaction energy barrier (0.37 eV).

Effective electronic waste valorization via microwave-assisted pyrolysis: investigation of graphite susceptor and feedstock quantity on pyrolysis using experimental and polynomial regression techniques.

Waste printed circuit board (WPCB) was subjected to microwave-assisted pyrolysis (MAP) to investigate the energy and pyrolysis products. In MAP, pyrolysis experiments were conducted, and the effects of WPCB to graphite mass ratio on three-phase product yields and their compositions were analyzed. In addition, the role of the initial WPCB mass (10, 55, and 100 g) and susceptor loading (2, 22, and 38 g) on the quality of product yield was also evaluated. By using design of experiments, the effects of graphite susceptor addition and WPCB feedstock quantity was investigated. A significant liquid yield of 38.2 wt.% was achieved at 38g of graphite and 100g of WPCB. Several other operating parameters, including average heating rate, pyrolysis time, microwave energy consumption, specific microwave power used, and product yields, were optimized for the MAP of WPCB. Pyrolysis index (PI) was calculated at the blending of fixed quantity WPCB (100g) and various graphite quantities in the following order: 2g (21) > 20g (20.4) > 38g (19.5). The PI improved by increasing the WPCB quantity (10, 55, and 100g) with a fixed quantity of graphite. This work proposes the product formation and new reaction pathways of the condensable compounds. GC-MS of the liquid fraction from the MAP of WPCBs without susceptor resulted in the generation of phenolic with 46.1% relative composition. The addition of graphite susceptor aided in the formation of phenolic and the relative composition of phenolics was found to be 83.6%. The area percent of phenol increased from 42.8% (without susceptor) to 78.6% (with susceptor). Without a susceptor, cyclopentadiene derivative was observed in a very high composition (~ 31 area %).

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

A novel solar disk chamber reactor for agricultural waste recycling and biochar production

The quality and properties of biochar are generally influenced by the nature of the raw materials and pyrolysis techniques. To assess the quality of sesame biochar production, a disc chamber reactor set on a solar parabolic dish concentrator was proposed as a modified slow pyrolysis technique. To evaluate the physicochemical characterizations of the produced biochar, two pyrolysis settings were used: 470 °C for 1 h (T1) and 440 °C for 2 h (T2) to produce biochar from sesame stalk feedstock (SS) using the proposed solar disk chamber reactor. Ash content, mass fraction of elements (C, H, and O%), pH, surface area, zeta potential, Fourier transform infrared (FTIR), and scanning electron microscope (SEM) were investigated. The results showed that the mass of T1 biochar decreased by 5% when compared to T2, while ash content, pH, fixed carbon, and volatile gases for both biochars were relatively close. The H/C and O/C molar ratios were below 1.00 and 0.4, respectively, indicating a loss of degradable polar contents and the formation of aromatic compounds. The surface area of T2 biochar was three times the surface area of T1, with the opposite trend in mean pore diameter. Two biochars showed the same FTIR peaks and SEM data, with small differences in their characteristics, demonstrating that pyrolysis time and temperature had a tight relationship. Both biochars showed approximately similar properties. The reactor’s efficiency is mainly affected by solar energy and atmospheric conditions during operation, which influence the average surface temperature. In Egypt, climatic conditions would be more favorable in the summer to improve the efficiency of parabolic solar dish concentrators for producing high-quality biochar.Graphical abstract

Optimasi Proses Pembuatan Asap Cair dari Tempurung Kelapa Melalui Response Surface Methodology (RSM)

Response Surface Methodology (RSM) is a collection of mathematical and statistical techniques that are useful for analyzing complex processes that are influenced by several variables. This research aimed to apply RSM in optimizing the process of making liquid smoke from coconut shell pyrolysis. Optimum process conditions were reviewed based on the content of several functional compounds in liquid smoke including carbonyl content, phenol content, and acid content. The process variables comprised pyrolysis temperature (within the temperature range of 350 oC as low level (-1) and 450 oC as high level (+1)), pyrolysis time (within the range of 45 minutes as low level (-1) and 75 minutes as high level (+1)), and the water content in the coconut shell (within the range of 10% water content as low level (-1) and 20% as high level (+1)). This study results showed that the best carbonyl content in liquid smoke was 3.58% at temperature of 395 oC, pyrolysis time of 60 minutes, and water content of 16%. The optimum phenol content of 5.55% was achieved with a combination of pyrolysis time of 65 minutes and water content of 15.5%. Based on the acid content, an optimum value of 19.55% was obtained at a combination of pyrolysis time of 62 minutes and water content of 15.5%. The hypothesis H0 could be accepted statistically for the carbonyl content.

Effects of thermal program on physicochemical properties and photocatalytic activity of g-C3N4 prepared by dicyandiamide pyrolysis

Graphitic carbon nitride (g-C3N4) can be prepared by the pyrolysis of dicyandiamide, and its properties and performance are greatly affected by the pyrolysis parameters. In this study, the effects of heating rate and pyrolysis time on the physicochemical properties and photocatalytic activity of the obtained g-C3N4 are systematically investigated, and the results are used to guide the controllable production of g-C3N4 in industry. The results show the heating rate has a significant impact on the pore structure, crystallinity, number of amino functional groups, and the stability of structure. The pyrolysis time mainly affects the texture and layer structure of g-C3N4 products. In addition, the polymerization pathways during the dicyandiamide pyrolysis are analyzed through in-situ TG-MS combined with XRD analysis, elucidating the process of dicyandiamide forming complete g-C3N4 products with high polymerization degree by polyaddition, polycondensation and rearrangement. This study provides useful reference strategies for the design of large-scale controllable industrial production of g-C3N4 through pyrolysis of dicyandiamide.

Microporous carbon prepared by microwave pyrolysis of scrap tyres and the effect of K+ in its structure on xylene adsorption

This work brings novel information about microwave-assisted pyrolysis of scrap tyres, the industrial realization of which is still an engineering challenge due to both missing fundamental processing issues as well as how to enhance the engineering quality of pyrolytic products, mainly of solid carbon black. One-step microwave pyrolysis of scrap tyres for 50 min at power of 440 W with KOH activation in the mass ratio of 1:3 (scrap tyres:KOH) is successfully applied for the first time to yield micropores-containing carbon black which application potential was verified for xylene adsorption from waste gas. Compared to conventional high-temperature pyrolysis, the microwave pyrolysis requires shorter time and thus significantly reduces input energy. Two-step microwave pyrolysis of scrap tyres at 440 W does not result in more organized graphene-based carbon, but turbostratic carbon is more perturbed. The higher microwave power of 950 W within one-step microwave pyrolysis does not enhance the graphitization of carbon black, but shorten the microwave pyrolysis time to 20 min. The two main physicochemical properties of the novel micro-macroporous carbon black determining its adsorption performance for xylene are the microporosity/large volume of micropores and K+ present in the carbon structure. Micropores <0.52 nm with/without K+ and cavities <0.82 nm with K+ within carbon structure are proved by molecular modeling to be the sites with the highest affinity for xylene adsorption. Higher adsorption capacity of activated carbon blacks compared to non-activated ones correlates with molecular modeling results. More perturbed carbon structure does not affect the xylene adsorption.

Making Charcoal from Nipah (Nypa fruticans) Frond Waste as an Adsorbent to Extend the Shelf Life of Fresh Bread

Fresh bread has high potential for creating food waste that increases every year, because of its relatively short shelf life of 3-4 days after leaving the baking process. One way to extend the shelf life of bread is by using charcoal. Nipah fronds contain lignin elements that are good for charcoal. This study aims to determine the characteristics of charcoal from nipah fronds, the effectiveness of charcoal's ability to extend the shelf life of fresh bread, the effect of burning time, particle size and adsorbent mass on the storage time of fresh bread, the effect of the ratio of nipah frond adsorbent to commercial silica gel on the storage time compared to quality requirements of fresh bread of SNI 01-3840-1995 2013. Charcoal characterization includes quality tests based on SNI No. 06-3730-1995 on technical charcoal, namely water content and iodine absorption parameters and also Scanning Electron Microscopy (SEM) test. Based on the results of the study, charcoal from nipah frond waste has characteristics of water content that have met the quality standards of SNI 06-3730-1995 and in iodine absorbency only samples with pyrolysis time of 4 hours that have met the quality standards of SNI 06-3730-1995. Giving variations in charcoal burning time, mass and particle size of adsorbent powder affects the shelf life and quality requirements of fresh bread. Adsorbent packaging using teabags and silica gel paper can extend the shelf life of fresh bread up to 27 hours compared to those without adsorbent.

Study on lightening of coal tar with metal oxide supported γ-Al2O3 catalyst

In this experiment, a fixed bed of pyrolysis was used to conduct pyrolysis with coal and a mixture of coal and catalyst, and the distribution and composition of tar products were studied. The pyrolysis of raw coal was carried out at different temperatures and at different constant temperature times, and the effects of pyrolysis temperature and constant temperature pyrolysis time on tar product formation from raw coal pyrolysis were studied. γ-Al2O3 was used as the carrier, and 4 kinds of alkaline earth metal oxides (MgO, CaO, SrO, BaO), 3 kinds of subgroup metal oxides (Fe2O3, Co2O3, NiO) and 5 kinds of VIII metal oxides (Cr2O3, MnO2, CuO, ZnO, MnO2) were selected as active components. The supported γ-Al2O3 catalyst was prepared by the method of equal volume impregnation and roasting in a muffle furnace. The γ-Al2O3 catalyst was characterized by means of XPS, BET and SEM, and the mechanism of the mixed pyrolysis of coal with different metal oxide supported catalysts to generate tar was studied. The results showed that: (1) under the conditions of 450 °C, 500 °C, 550 °C and 600 °C, the maximum tar yield was 0.32 g at 600 °C, and the tar yield was higher at constant temperature for 15 min than at final temperature of 600 °C, with an increase of 15.63%. (2) Fe2O3/γ-Al2O3 catalyst resulted in the highest tar yield of 0.75 g, which was 134.38% higher than that of coal pyrolysis. (3) From the increase of light oil and phenol oil and the decrease of anthracene oil and asphalt, Co2O3/γ-Al2O3, Fe2O3/γ-Al2O3 and Cr2O3/γ-Al2O3 can improve the tar quality better.

Insights into the influence and mechanism of biomass substrate and thermal conversion conditions on Fe[sbnd]N doped biochar as a persulfate activator for sulfamethoxazole removal

Fe-N-doped biochar is a promising material for advanced-oxidation heterogeneous catalysis, but its adsorption-catalytic performance is significantly affected by biomass feedstock compositions and thermal conversion conditions and is not yet conclusive. In this paper, four lignocellulosic biomasses (rice straw, bamboo, poplar wood, and corn stover) were selected as raw materials to prepare Fe-N-biochar as persulfate activators by hydrothermal-thermolysis composite. Their lignocellulosic fractions and elemental contents were detected, and a variety of thermal conversion conditions were investigated for the rice straw-based Fe-N-biochar with the best activation performance among them. It was found that the holocellulose and lignin contents of the biomass affected the catalytic activity of the prepared catalysts with correlation coefficients of 0.57 and −0.93, respectively. Increasing the pyrolysis temperature from 500 °C to 800 °C could increase the ratio of Fe2+/Fe3+ and the relative amounts of CC, graphitized N, and oxidized N in the catalyst by 0.17 %, 7 %, 12 %, and 18 %, respectively. Extending the pyrolysis time from 0.5 to 2 h was able to increase the relative content of CC, graphitized N, and oxidized N by 0.18 %, 3 %, 9 %, and 4 %, respectively. The most catalytically active rice straw-derived Fe-NRBC was able to remove 91.7 % of sulfamethoxazole (SMX) and 93.07 % of TOC mainly via ·SO4− and ·OH in an adsorption-catalytic reaction of 60 min with a k of 0.047 min−1 and the main active sites are FeN, Fe0, pyridine N, oxidized N and CO. Finally, degradation intermediates and pathways were also characterized. This paper is expected to provide a basis for the future targeted regulation of Fe-N biochar for water pollution treatment.

Comparative techno-economic assessment of production of microcrystalline cellulose, microcrystalline nitrocellulose, and solid biofuel for biorefinery of pistachio shell

The biorefinery of pistachio shell (PS) for producing microcrystalline cellulose (MC), microcrystalline nitrocellulose (MNC), and biochar (PSB) was techno-economically assessed. A rapid recyclable nitric acid treatment purely isolated 32–41 % of PS as MC particles (crystallinity index of 86 %) at 80 °C for 90 min. A facile synthesis obtained MNC particles (crystallinity index of 79 %) with a nitrogen content of 10.81 % from the MC. The PSB with the HHV value of 27.82 MJ/kg and 24 % production yield was achieved as biocoal via pyrolysis at 400 °C for 30 min. The incorporation of sulfuric acid pre-dehydration with pyrolysis temperature and time improved the PSB yield up to 28 %, while lowering the HHV to 24.12 MJ/kg. The NPV, IRR, ROI, and payback time indicated that the MC and MNC production from PS could make them suitable for future commercialization; however, the PSB production was not profitable because it could not compete with coal.

Modeling and optimization of the yield of pyrolytic oil from waste face masks using RSM‐ANN‐LM hybrid approach

AbstractPyrolysis is one of the most widely practiced thermochemical conversion technique to convert biomass into bio fuel. In this investigation, waste surgical masks were taken for pyrolysis process and the pyrolysis oil yield was determined experimentally. The experiments were designed and optimized based on Box Behnken Design (BBD) with operating parameters (feed size, temperature, and time) to study the effect on the yield of the pyrolysis oil and char. Experiments were conducted by varying the feed size (10–50 mm), pyrolysis temperature (400–600°C), and time (30–90 min). A hybrid Response Surface Methodology –Artificial Neural Network‐ Levenberg–Marquardt algorithm (RSM‐ANN‐LM) modelling approach has been to optimize the process parameters for the prediction of pyrolysis oil yield. The optimized network architecture was found to be 3‐10‐1 and the authenticity of the developed model has been evaluated using Regression Co‐efficient (R2) and Mean Squared Error (MSE). The developed RSM‐ANN‐LM model has outperformed the RSM model on predicting the pyrolytic oil yield. For the optimized conditions of 10 mm size, 600°C of pyrolysis temperature and 90 min pyrolysis time, 85.30% oil yield was obtained.

Numerical simulation of heat transfer properties of large-sized biomass particles during pyrolysis process

During the pyrolysis process of large particles, the conduction between particles cannot be ignored. In the present work, a numerical simulation model for the pyrolysis of biomass particles was established, which takes into account the conduction within the particles. Based on this model, the temperature distribution inside the particle during the pyrolysis process was determined and the effects of particle size, moisture content, and gas velocity on heat transfer characteristics were analyzed. The results showed that the temperatures at different positions of the particles along the inflow direction were quite different, and the maximum temperature difference inside the particles was about 146.7 K for a particle diameter of 10 mm and a velocity of 0.2 m/s. During the pyrolysis process of biomass particles, there were two peaks of Nusselt number. The increase of moisture content prolonged the pyrolysis time. The pyrolysis.time of particles with moisture content of 15 % was about 1.5 times longer than that of dry particles when the particle diameter was 10 mm. Increasing the particle size decreased the difference between the two peaks and increased the time interval between the two peaks. Increasing the gas velocity can improve the heat transfer, but the effect of too high gas velocity on improving the heat transfer is limited. The present study is of great importance for a detailed understanding of the pyrolysis process of biomass particles.

Insight into the impacts of pyrolysis time on adsorption behavior of Pb2+ and Cd2+ by Mg modified biochar: Performance and modification mechanism

Co-pyrolysis biomass and alkaline metals can effectively improve the adsorption performance of heavy metals (HM). Nevertheless, the researchers have ignored the relationship between the change of alkaline metal morphology and adsorption during pyrolysis. In this article, according to control the pyrolysis time (30, 60, and 180 min) synthesized Magnesium (Mg) modified biochar (MBCX) by using MgCl2·6H2O and soybean straw under 400 °C. The sorption capacities of MBC60 and MBC180 for Pb2+/Cd2+ increased by 38.65%/213.29%, 44.57%/230.36%, and the selectivity coefficient of Pb2+/Cd2+ increased by 113.28%/209.49%, 213.58%/253.62%, respectively, compared with MBC30. Additionally, the characterization results demonstrated that MgO dominated the surface phases of MBC60 and MBC180, whereas MgCl2 dominated the surface phases of MBC30. Moreover, according to the results of DFT calculation, the adsorption energy (Eads) of MgO for Pb2+ (−0.537 eV) and Cd2+ (−0.347 eV) was lower than that of MgCl2 (Pb2+: 0.37 eV, Cd2+: −0.185 eV), so that, MBC60 and MBC180 had higher sorption capacities for Pb2+ and Cd2+ than MBC30. Therefore, this work provides a new sight to clear the mechanism for modified biochar by alkali metal oxide and practical and theoretical guidance for adsorbent preparation with high adsorption ability for HMs.

Peningkatan Produktivitas Tanah Sulfat Masam dan Hasil Padi Menggunakan Bioarang dari Limbah Industri Penggergajian Kilang Kayu

The study aims to analyze three aspects. (1) Formulation of biochar from wood refinery sawmill waste at pyrolysis temperatures of 450°C and 550°C with pyrolysis times of 2 and 4 hours. (2) The best wood refinery sawing waste biochar dosage to improve the chemical quality of acidic sulfate soil through improving soil pH, Al-dd, N, P, and K of the soil. (3) Growth and production of paddy on acidic sulfate soils by application of ameliorant biochar of waste sawmill wood mill. The research was conducted in acidic sulfate soil in a screen house in the Experimental Garden of the Faculty of Agriculture, Syiah Kuala University. Soil samples and biochar were analyzed at the Soil and Plant Research Laboratory of the Faculty of Agriculture. The study was an experiment using a factorial complete randomized design with two factors: the temperature and pyrolysis time and the dose of biochar. The results showed that the application of biochar waste from sawmill wood refineries had a very significant and significant effect on improving the quality of acidic sulfate soil and the growth and production of rice fields. The formulation of biochar at a pyrolysis temperature of 550°C for 2-hour pyrolysis with 20 tons/ha is the best improvement in acid sulfate soil quality, growth, and rice field production.&#x0D; &#x0D; Keywords: acid sulphate, biochar, paddy