Pyrolysis Biochar Research Articles

Co-pyrolysis of municipal and horticultural wastes for enhanced biochar and bio-oil production: A response surface methodology approach

Pyrolytic biochar is a promising approach to the withdrawal of CO2 and reduction of Green House Gases. One of the effective techniques to improve the properties of biochar with desired characteristics is co-pyrolysis of types of biomass. Among the types of biochar, biochar from nitrogen-rich biomass pyrolysis has various applications, including soil amendment and removal of organic pollutants. The aim of this study is co-pyrolysis nutrient-rich municipal (household) and horticultural wastes for N-doped biochar production and provide optimal conditions for the production of pyrolytic products. A series of experiments were designed with municipal and horticultural wastes at different mass ratios in a fast catalytic reactor at 550 °C with varying catalyst amounts (0–15 %) and waste blend ratios (0–100 wt%) were designed using the response surface methodology. The yields of bio-oil, biochar, and biogas were quantitatively and qualitatively assessed. Statistical analysis showed that that the horticultural-to-household wastes ratio has the most critical effect on the biochar yield. The optimum N-doped biochar yield (26 wt%) was achieved at the household-to-horticultural wastes ratio of 1.5 without using the catalyst. Also, the result showed that adding municipal waste increased bio-oil yield significantly from 18 % to 58 %. Moreover, increasing the catalyst amount raised gas yield to 37 %, and horticultural waste favored biochar formation (53 %). The optimized product showed carbon enrichment and oxygenated compound reduction the result is bio-oil production with a higher heating value. Gas chromatography-mass spectrometry (GC–MS) analysis of volatile products indicated that the co-pyrolytic oil was rich in N-containing compounds (Pyrrole, Pyridine, and Indole)which is widely used in pharmaceutical and polymer industries. Synergistic interactions between municipal and horticultural wastes significantly reduced the amount of carboxylic acids, alcohols, ketones, and esters, whereas phenols formation as valuable chemicals were increased. Therefore, this study shows that co-pyrolysis is a suitable approach for household and horticultural waste management that can increase the production of N-doped biochar and also be a sustainable source for the extraction of nitrogen-containing biochemical products.

Application and functionalization of toxic waste sludge-derived biochar for efficient phosphate separation from aqueous media: Toxicity diminution, robust adsorption, and inner mechanism

Phosphorus control and the disposal of municipal solid waste have drawn increasing concerns. Herein, we reported the reutilization and functionalization of highly toxic waste sludge derived from landfill leachate treatment process for biochar preparation and therefore phosphate elimination from aqueous media. Toxicity analysis confirmed largely declined heavy metal leaching and diminished ecological risks during biochar pyrolysis, providing a feasible option for the disposal and reutilization of toxic waste. Pre-loading of lanthanum rendered fabricated biochar with robust phosphate adsorption capacity, with optimized composite achieving maximum capacity of ∼94.4 mg P/g at pH 6. Effects of environmental factors, especially co-existing species (anions, cations and dissolved organic matters), were systematically evaluated combining experimental results and characterization analysis. Thereafter, adsorption behaviors of synthesized samples including kinetic, isotherm and thermodynamics were comprehensively explored. In virtue of characterization analysis, physicochemical properties of different composites and phosphate separation mechanism that involved electrostatic attraction and inner-sphere complexation were fully probed. Overall work investigated the feasibility of toxicity reduction via pyrolysis, phosphate uptake performance and inner mechanism, therefore highlighting the potential of waste reutilization for environmental remediation.

Poplar Sawdust Biochar Altered Community Composition of Dominant Soil Fungi but Not Bacteria Depending on Pyrolysis Temperature

There is a growing focus on the production of biochar from organic wastes and its forestry use. However, it is unclear how applying biochar pyrolyzed at different temperatures influences both soil bacterial and fungal communities. In this study, two kinds of biochar were pyrolyzed at 350 °C and 600 °C, from poplar sawdust, and then applied as an auxiliary substrate material (15% addition by volume) for the container seedling cultivation of Cyclocarya paliurus, a native timber and medically used tree species, to compare the response of the soil’s microbial traits. The results showed that after 5 months of cultivation, the addition of the biochar application improved the soil’s physical and chemical properties to a certain extent by decreasing its bulk density and increasing its field water-holding capacity, pH and organic carbon content. The soil’s pH and content of organic C, available N and available P were significantly higher in the substrate with the addition of the biochar pyrolyzed at 600 °C (Bioc600) than in that of the substrate with added pyrolyzed biochar at 350 °C (Bioc350). The biochar application also enhanced the soil’s microbial N (MBN) but showed no changes in the MBC/MBN ratio. The biochar application had no effect on the diversity and composition of the soil’s bacterial community, but showed a certain effect on its fungal community composition and had different influences between low and high pyrolysis temperatures. The relative abundance of several of the dominant fungal phyla and genera increased with the addition of biochar due to the increase in the soil’s pH when compared to the CK (no biochar or sawdust addition). When compared with Bioc350, the dominant phylum Basidiomycota and genus Vanrija further increased in abundance with Bioc600. These findings reveal the consistent effects of biochar pyrolysis temperature and demonstrate the different regulatory roles of biochar application in soil bacterial and fungal communities, providing valuable information on how biochar can effectively be used as a substrate for seedling cultivation.

Effective toluene removal from aqueous solutions using fast pyrolysis-derived activated carbon from agricultural and forest residues: Isotherms and kinetics study

In this study, the production and characterization of activated carbons (ACs) from agricultural and forest residue using physical activation are discussed. Biomass-based biochars produced during fast pyrolysis process is introduced as alternative precursors to produce AC and the integrated process for the co-production of porous adsorbent materials from biochar via the fast pyrolysis process is suggested. Moderate surface areas and good adsorption capacities were obtained from switchgrass (SWG) and pine tops (PT) based AC. The surface areas were 959 and 714 m2/g for SWG- and PT-based AC, respectively. The adsorption capacities using toluene as pollutant for two model systems of 180 and 300 ppm were measured and ranged between 441-711 and 432–716 mg/g for SWG-based and PT-based AC, respectively. The nitrogen adsorptive behavior, Lagergren pseudo-second-order kinetic (PSOK) model and kinetics isotherms studies describe a heterogeneous porous system, including a mesoporous fraction with the existence of a multilayer adsorption performance. The presence of micropores and mesopores in SWG- and PT-based AC suggests potential commercial applications for using pyrolytic biochars for AC production.

Study on the adsorption characteristics of lead in soil by biochar from co-pyrolysis of rice straw and sludge

The adsorption kinetics and short-term soil adsorption experiments were carried out for the biochar (mixed charcoal) prepared by co-pyrolysis of rice straw and sludge. The results showed that the specific surface area and total pore volume of co-pyrolysed biochar were significantly increased compared with sludge pyrolysis biochar. In the lead solution adsorption experiment, the removal rate of lead ions in the solution reached 99.34% using mixed-burning biochar produced at 600 °C for 24h, and the unit mass adsorption capacity was 64.57 mg/g. In the soil adsorption experiment, 12 g/kg of mixed charcoal was added to lead-contaminated soil, and the leaching toxicity and bioavailability of lead-contaminated soil after stabilization for 30 days decreased by 45.3% and 37.0%, respectively. The soil pH value with 12 g/kg of mixed charcoal added within 30 days fluctuated between 7.03 and 7.12, and no acid or alkaline pollution was generated. Co-pyrolysed biochar can effectively reduce the leaching toxicity and bioavailability of lead in soil. For soil with a lead pollution concentration of less than 1600 mg/kg, adding 12 to 16 g/kg of co-pyrolysed biochar produced at 600 °C can achieve a satisfactory repair effect.

Assessment of pine wood biomass wastes valorization by pyrolysis with focus on fast pyrolysis biochar production

Assessment of pine wood biomass wastes valorization by pyrolysis with focus on fast pyrolysis biochar production

Biochar as a Green Sorbent for Remediation of Polluted Soils and Associated Toxicity Risks: A Critical Review

Soil contamination with organic contaminants and various heavy metals has become a global environmental concern. Biochar application for the remediation of polluted soils may render a novel solution to soil contamination issues. However, the complexity of the decontaminating mechanisms and the real environment significantly influences the preparation and large-scale application of biochar for soil ramification. This review paper highlights the utilization of biochar in immobilizing and eliminating the heavy metals and organic pollutants from contaminated soils and factors affecting the remediation efficacy of biochar. Furthermore, the risks related to biochar application in unpolluted agricultural soils are also debated. Biochar production conditions (pyrolysis temperature, feedstock type, and residence time) and the application rate greatly influence the biochar performance in remediating the contaminated soils. Biochars prepared at high temperatures (800 °C) contained more porosity and specific surface area, thus offering more adsorption potential. The redox and electrostatic adsorption contributed more to the adsorption of oxyanions, whereas ion exchange, complexation, and precipitation were mainly involved in the adsorption of cations. Volatile organic compounds (VOCs), dioxins, and polycyclic aromatic hydrocarbons (PAHs) produced during biochar pyrolysis induce negative impacts on soil alga, microbes, and plants. A careful selection of unpolluted feedstock and its compatibility with carbonization technology having suitable operating conditions is essential to avoid these impurities. It would help to prepare a specific biochar with desired features to target a particular pollutant at a specific site. This review provided explicit knowledge for developing a cost-effective, environment-friendly specific biochar, which could be used to decontaminate targeted polluted soils at a large scale. Furthermore, future study directions are also described to ensure a sustainable and safe application of biochar as a soil improver for the reclamation of polluted soils.

Low temperature pyrolytic biochar is a preferred choice for sulfonamide-Cu(II) contaminated soil remediation in tropical climate region

Biochar is getting increasing consideration for eco-friendly soil amendment and environmental remediation. Once added to the soil, biochar would undergo the natural ageing process, affecting its physicochemical properties and, as a result, the adsorption and immobilization of pollutants in the water and soil. To evaluate the high/low temperature pyrolyzed biochar performance on complex contaminants and the effect of climate ageing, the batch experiments were conducted on the adsorption of the pollutants of antibiotics sulfapyridine (SPY) and a typical coexisting heavy metal Cu2+ as one or binary system on low/high pyrolytic temperature biochars before and after the simulated tropical climate and frigid climate region ageing treatment. The results showed that high-temperature ageing could enhance the SPY adsorption in biochar-amended soil. The SPY sorption mechanism was fully elucidated, and the result confirmed that H-bonding was the dominant role in biochar-amended soil, and π-π electron-donor-acceptor (EDA) interaction and micro-pore filling was another factor for SPY adsorption. This study could lead to the conclusion that low-temperature pyrolytic biochar is a better option for sulfonamide-Cu(II) contaminated soil remediation in tropical regions.

Pyrolysis Atmospheres and Temperatures Co-Mediated Spectral Variations of Biochar-Derived Dissolved Organic Carbon: Quantitative Prediction and Self-Organizing Maps Analysis.

Biochar-derived dissolved organic carbon (BDOC), as a highly activated carbonaceous fraction of biochar, significantly affects the environmental effect of biochar. This study systematically investigated the differences in the properties of BDOC produced at 300-750 °C in three atmosphere types (including N2 and CO2 flows and air limitation) as well as their quantitative relationship with biochar properties. The results showed that BDOC in biochar pyrolyzed in air limitation (0.19-2.88 mg/g) was more than that pyrolyzed in N2 (0.06-1.63 mg/g) and CO2 flows (0.07-1.74 mg/g) at 450-750 °C. The aliphaticity, humification, molecular weight, and polarity of BDOC strongly depended on the atmosphere types as well as the pyrolysis temperatures. BDOC produced in air limitation contained more humic-like substances (0.65-0.89) and less fulvic-like substances (0.11-0.35) than that produced in N2 and CO2 flows. The multiple linear regression of the exponential form of biochar properties (H and O contents, H/C and (O+N)/C) could be used to quantitatively predict the bulk content and organic component contents of BDOC. Additionally, self-organizing maps could effectively visualize the categories of fluorescence intensity and components of BDOC from different pyrolysis atmospheres and temperatures. This study highlights that pyrolysis atmosphere types are a crucial factor controlling the BDOC properties, and some characteristics of BDOC can be quantitatively evaluated based on the properties of biochar.

Optimization of flexural properties and thermal conductivity of Washingtonia plant biomass waste biochar reinforced bio-mortar

The building industry's current trend to reduce and protect environmental impact implies the design and fabrication of more ecological and sustainable building materials. Biochar has the potential to be incorporated in construction materials for its specific characteristics and environmental advantaaffnciges that it offers. Plasters are susceptible to cracking and spalling due to environmental conditions. This study offers the development of a novel bio-mortar biochar-reinforced plaster products obtained by pyrolysis of Washingtonia plant biomass biochar (WPBB). Three biochar contents (1, 2 and 3%) according to three temperatures (300, 400 and 500 °C) were examined. Sample characterization, such as FTIR (Fourier Transform Infrared Spectroscopy) and SEM (Scanning Electron Microscopy), was conducted to investigate bio-mortars obtained from biomass waste biochar. The incorporation of WPBB led to increased bending strength and decreased ductility compared to reference data of plaster biocomposite i.e.: 229%, 200% respectively, for the reinforced plaster with an optimum content of 1 w% pyrolyzed biochar at 500 °C. However, it was found that the use of less than 2 wt% biochar could give plaster biocomposites superior performance to conventional materials and the 2% biochar content improved the ductility compared to the 1% and 3% contents.; Adding biochar to mortar improved thermal performance compared to the reference mixture, allowing its use as a material for moisture control. Furthermore, the models generated using RSM response surface methodology and ANN neural networks agreed well with those obtained experimentally for the bending properties the newly conceived plaster/biochar biocomposite. Gypsum bio-mortars containing WPBB can be utilized to create lightweight mortars with exceptional qualities including low density and thermal insulation.

Preliminary Assessment of Pyrolysis Biochar Derived from Milk/Dairy Processing Sludge as a Potential Component of Fertilizers

Disposal of waste-activated sludge [dairy processing sludge, (DPS)] from wastewater treatment plants located in milk processing companies is an increasing concern. DPS is usually applied to farmlands in the vicinity of the dairy companies. This practice is becoming unsustainable due to uncontrolled nutrient loss and potential soil contamination. We propose to recover nutrients in the form of biochar. This paper examines the properties of biochars obtained from slow pyrolysis of DPS. DPS samples were pyrolyzed at laboratory and pilot scale at 600 and 700 °C. The elemental properties of biochars, the content of primary and secondary nutrients, as well as contaminants were examined and compared against the European Union Fertilizing Products Regulation. The biochars meet the specified limits for hydrogen-to-organic carbon ratio, chloride, and polycyclic aromatic hydrocarbons intended for gasification and pyrolysis component category materials. In six out of eight biochars, the content of phosphorus (P) as a single declared nutrient and the level of contaminants meet those required for an organo-mineral fertilizer. Only two biochars meet the required concentrations of nitrogen, phosphorus, and potassium. A minimum solid content of 30% in DPS is required to make the process of biochar production energetically sustainable.

Waste By-Product of Grape Seed Oil Production: Chemical Characterization for Use as a Food and Feed Supplement.

Among the waste materials of wine production, grape seeds constitute an important fraction of the pomace, from which the precious edible oil is extracted. The residual mass from oil extraction, the defatted grape seeds (DGS), can be destined for composting or valorized according to the circular economy rules to produce pyrolytic biochar by gasification or pellets for integral energy recovery. Only a small quantity is used for subsequent extraction of polyphenols and tannins. In this study, we performed a chemical characterization of the DGS, by applying spectroscopic techniques (ICP-OES) to determine the metal content, separation techniques (HS-SPME-GC-MS) to evaluate the volatile fraction, and thermal methods of analysis (TGA-MS-EGA) to identify different matrix constituents. Our main goal is to obtain information about the composition of DGS and identify some bioactive compounds constituting the matrix in view of possible future applications. The results suggest that DGS can be further exploited as a dietary supplement, or as an enriching ingredient in foods, for example, in baked goods. Defatted grape seed flour can be used for both human and animal consumption, as it is a source of functional macro- and micronutrients that help in maintaining optimal health and well-being conditions.

Design and preparation of carbon material catalyst modified with metal framework and sulfonate for biochar generation from low-temperature directional pyrolysis of kitchen waste: Mechanism and performance

In order to reduce the pyrolysis temperature during the process of directional conversion from kitchen waste (KW) into aromatic biochar, a kind of catalyst was prepared with carbon material coated with tri-metallic oxide (Fe2O3, MgO and Al2O3) combining with sulfonic acid groups (CMO@SA) according to KW compositions. The aromaticity of KW pyrolysis biochar (KWB) increased when the temperature ranged from 170 to 210 °C. The catalytic pyrolysis temperature of KW reduced from 500 to 190 °C for biochar generation with similar aromaticity due to amendment of CMO@SA. The maximum adsorption capacity of catalytic pyrolysis KWB was 160.23 mg/g for dyeing wastewater, which was equivalent to biochar generated at 500 °C. The decrease of pyrolysis temperature was attributed to the reduction of bonds fracture activation-energy among CH, CC and CO under the catalytic function. The catalytic activity and recovery of CMO@SA kept at 92 % and 90 % after five recycle.

Biomass inherent metal interfere carbothermal reduction modification of biochar for Cd immobilization

Metal salt laden are frequently used to enhance the heavy metal adsorption capacity of biochar. The present study indicates that CaS loading biochar can be modified from the carbothermal reduction reaction between CaSO3 (modification agent) and carbon matrix. The CaS transformation ratio as indicated by XPS spectra was significantly improved by the CaSO3 loading content. The coprecipitation reaction induced by the CaS in biochar can significantly enhance the adsorption capacity of heavy metals (Cd). And, the Cd adsorption capacity can be enhanced up to >100 mg/g and increases with increasing CaS ratio in the biochar. In addition, the adsorption process was rapid and could be balanced within several minutes (~ 5 min). Furthermore, the interaction reaction between the modification agent and the inherent metal in the biomass was examined in the biochar pyrolysis preparation process. Interestingly, MgCl2 inherent metal salt can combine with the original CaSO3 to produce a new mineral, resulting in a decrease in CaS. However, KCl, a more thermally stable biomass-derived metal salt, exhibited a weak combination ability with the modification agent. Accordingly, this type of secondary reaction reduces the Cd adsorption capacity owing to the decrease in the number of adsorption sites (CaS).

Tea biochar-immobilized Ralstonia Bcul-1 increases nitrate nitrogen content and reduces the bioavailability of cadmium and chromium in a fertilized vegetable soil

Pyrolytic biochar (PL-BC, pyrochar) and hydrothermal biochar (HT-BC, hydrochar) derived from branches and leaves of tea plants had different pH, electrical conductivity (EC), total carbon nitrogen content, BET surface area, total pore volume, average pore diameter, and functional groups. HT-BC had a larger specific surface area and more functional groups than PL-BC. Ralstonia Bcul-1 (R-B) was the dominant and functional bacteria in a fertilized vegetable soil supplemented with TBB-immobilized R-B (TBB + R-B). R-B vitality was more closely related to BET surface area, total pore volume, and functional groups of tea-based biochar (TBB: PL-BC and HT-BC). R-B was able to maintain high oxidase activity. R-B and TBB + R-B can increase the activities of urease and peroxidase in vegetable soil playing an essential role in the biotransformation of ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3−-N). TBB was able to simultaneously increase the content of NO3−-N and NH4+-N, and TBB + R-B also significantly increased NO3−-N content but decreased NH4+-N content in a fertilized vegetable soil. These results indicated that R-B promoted nitrification in the soil, i.e. conversion of NH4+-N into NO3−-N, by enhancing the activities of urease and peroxidase. R-B had high adsorption capacity for cadmium (Cd) and chromium (Cr) (Cd&Cr: Cd and Cr). Moreover, TBB + R-B was able to convert weak acid extractable and reducible Cd&Cr into a more stable residual fraction and oxidizable Cd&Cr. The overall effect of the treatments was to reduce plant uptake of Cd&Cr by cabbage. TBB + R-B significantly promoted R-B growth, changed inorganic nitrogen speciation, increased NO3−-N supply, reduced Cd&Cr bioavailability, and decreased plant tissue Cd&Cr content.

Co-pyrolysis of sewage sludge and poplar sawdust under controlled low-oxygen conditions: Biochar properties and heavy metals behavior

Biochar production by pyrolysis of sewage sludge (SS) is one of effective ways to realize resource recovery and harmless treatment of SS. However, biochar prepared by direct pyrolysis of SS has a lower specific surface area and higher heavy metal content. This study was aimed to evaluate the effect of low-oxygen and addition of poplar sawdust (PS) on sludge-derived biochar. The properties of biochar and heavy metals behavior were systematically characterized. The presence of 10% O2 during SS pyrolysis had a significant effect on the specific surface area of the pyrolytic biochar and the chemical species of heavy metals. In comparison with the pyrolytic biochar under N2 atmosphere, the yield of co-pyrolytic biochar from 10% O2 decreased by 6.7% at 350 °C and 8.3% at 650 °C, while it had the highest fixed carbon content of 19.6%. Moreover, the addition of PS also increased the specific surface area of pyrolysis biochar to 26.8 m2 g−1 at 650 °C. With the increase of pyrolysis temperature, heavy metals including Zn, Cr, and Cu in SS were transformed from the exchangeable and reducible states to oxidizable states and residue states. Especially, the presence of 10% O2 can also promote the formation of oxidizable states of heavy metals in biochar. Based on risk assessment code analysis, the ecotoxicity of heavy metals in biochar with the presence of O2 was evidently lowered. Therefore, a low oxygen atmosphere and co-pyrolysis of sludge and biomass could be effective ways to improve the quality of sludge-based biochar.

Energetska svojstva poljoprivredne biomase nakon pirolize

At the beginning and during the development of civilization, natural sources were the only available source of energy. With the development of society and industry, they were replaced by intensive use of fossil fuels. Non-renewability and negative impact on the environment called into question the rationality of using such sources. Therefore, natural sources of energy are becoming more and more important, especially biomass, which is becoming an important source of energy due to its ecological advantages. There are numerous ways to convert agricultural biomass into different forms of biofuel. Thermochemical conversion includes a process of pyrolysis in which, under the influence of a high temperature of 400 to 600 °C without the presence of oxygen, very valuable products are obtained in the form of biochar. The aim of this research is to evaluate the energy properties of agricultural biomass (corn, wheat, barley, oats, triticale, rye, soybeans, rapeseed and sunflower) by thermochemical conversion by pyrolysis and analysis of biochar for the evaluation of value-added products and to suggest its application. The mentioned raw materials are characterized by significant pyrolytic conversion potential, i.e. biochar production ranged from 30.03% to 47.0%. Similarly, the heating value (HHV) of biochar after the pyrolysis process increased to 27.11 MJ/kg, which proves that agricultural biomass is a good source of energy per unit mass.

Estudo da adsorção de cromo usando biochar proveniente de bagaço de malte: cinética e termodinâmica

ABSTRACT: Brewer’s spent grain (BSG) is a residue from brewery production, that can be reused as adsorbent of heavy metals like Chromium (Cr). In this study, BSG was used as a biochar for Cr adsorption in batch adsorption experiments. The biochar pyrolysis temperature (500, 600 and 700ºC), pyrolysis time (30, 105 and 180 minutes) and zinc chloride concentration (5, 12.5 and 20%) were evaluated and optimized from a fractional factorial design. An equilibrium adsorption capacity of 78.13 mg.g-1 and a yield of 26.42% were achieved using 700ºC, 30 min, 12.5%. This biochar was applied to the adsorption of Cr in aqueous solution, under different stirring speeds (100, 150 and 200 rpm). The higher agitation speed reduced the adsorption capacity of the coal from 90 to 72 mg.L-1. In addition, the Cr adsorption equilibrium was reached before 100 min. The pseudo-first order model best described the Cr adsorption kinetics. The Redlich-Peterson isothermal model best fitted the experimental data, with the parameter g (close to 1) suggesting Langmuir’s assumptions as the most appropriate to describe the adsorption of Cr on the optimized activated carbon.

Pengaruh Suhu Terhadap Karakteristik Arang Hasil Pirolisis Kulit Kolang-Kaling (Arenga pinnata)

Sugar palm plants are included in the top ten plantation commodities in East Kalimantan. So far, kolang-kaling fruit peel waste has not been widely used, except for fertilizer. Palm peel waste has a non-uniform texture, but the inside is hard, so it can be used to make charcoal. Charcoal is made by pyrolysis process and can be used as raw material for briquettes as a new renewable energy source. This study aims to obtain biochar as a raw material for making briquettes with the highest calorific value through the pyrolysis process. The manufacture of biochar begins with the drying process of the raw materials and then proceeds with heating the sample in a pyrolysis reactor for 1 hour. The process takes place with the constant variable is the sample weight of 500 g and the heating time for 1 hour, and the variable that changes is the combustion temperature. Pyrolysis was carried out at temperatures of 200 °C, 250 °C, 300 °C, 350 °C, and 400 °C. The mass of charcoal obtained was 487.23 g, 438.37 g, 402.03 g, 318.1 g and 278.84 g. The resulting calorific value is 4158.7 cal/g, 4432.5 cal/g, 4620.2 cal/g and 4840.7 cal/g. The ash content were 12.01%, 14.64%, 14.99%, 15.25% 21.98%, respectively. Volatile Matter obtained 76.50%, 69.67%, 61.68%, 56.71%, 47.15%. While the fixed carbon biochar is 0.80%, 8.93%, 9 78%, 11.30%, 16.31%. The characteristics of the pyrolysis biochar are seen by proximate testing. Biochar with the highest calorific value was obtained at a temperature of 400 °C, namely 4840.7 cal/g. Keywords: Palm fruit peel, Calorific value, Pyrolysis , Charcoal

Pyrolytic biochar from plastic film waste addition on farmland for maize growth improvement: Process and effect study

Pyrolyzing and returning to farmland is one of the potential methods for farmland plastic film waste. This study explored both pyrolyzation and activation optimum conditions of a mixture of plastic film (polyethylene) and maize straw (MPS) in a 1:5 ratio to produce MPS-char, investigated the action of the char on the maize seedling stage (for 30 days). The results showed that the char promoted the root to be more advanced than aboveground part, therefore, this study experimentally clarified the role MPS-char played when added to the soil. The functional groups of the char were varied by the participation of polyethylene. Carbon-based groups were observed, such as carbonyl or carboxyl groups, which could constitute an NH4+ absorption release system to increase the existence of urea in soil, therefore the average nitrogen concentration was improved by 16.18 %. However, the shallow soil temperature increased by 2.03 °C, and the deep soil temperature slightly decreased with the effect of MPS-char. While, the soil moisture content was slightly reduced in the second half of the experiment, and the soil oxygen content increased by 7.64 % throughout the whole experiment. Overall, returning MPS-char to farmland showed a positive effect on maize growth, which was caused by the variation of both chemical and physical properties. This variation provides opportunities for further promotion of rhizosphere development.