Pyrolysis Of Agricultural Wastes Research Articles

Enhanced bioremediation of hexavalent chromium via Stenotrophomonas acidaminiphila 4–1 assisted with agricultural wastes-derived biochar

Chromium (Cr) contamination in soil poses high toxicity risks to organisms. In this study, a Cr(VI)-resistant strain was isolated from oil-contaminated soil and designated as Stenotrophomonas acidaminiphila 4–1. The optimal removal efficiency of Cr(VI) (67.4 %) was achieved by employing the response surface methodology, with a glucose concentration of 6.1 %, soil moisture content of 31 %, inoculation dose of 4.5 mL, and initial Cr(VI) concentration of 0.2 mg·g−1. The strain 4–1 was immobilized in biochar derived from the pyrolysis of agricultural waste, including corn straw, loofah, and reed straw. In the loofah biochar-4–1 group, the removal efficiency of Cr(VI) was 74.94 % when the initial concentration of Cr(VI) was 0.2 mg·g−1. The biochar-immobilized strain 4–1 exhibited superior removal efficiency and tolerance towards Cr(VI) compared to the single free strain 4–1.The FT-IR results revealed that the surface functional groups of reed straw biochar exhibited a higher abundance compared to those of corn straw biochar and loofah biochar. The predominant form of Cr(VI) in untreated soil was found to be residual form, while the proportion of Fe-Mn oxides form increased from 7.9 % to 18.8 % within a span of 14 days. Notably, loofah biochar-4–1 exhibited the ability to convert unstable chromium species into stable forms within the soil. This work offers a specific instructive method to for remediating Cr polluted sites.

Biochar from agricultural biomass: Green material as an ecological alternative to solid fossil fuels

The stalks left after harvesting corn, tomatoes, and tobacco have no further use and are usually burned on agricultural land. In our work samples of this waste were collected and pyrolyzed at 400 ? for 30 min in a nitrogen atmosphere. The solid residue (biochar) obtained by pyrolysis was analyzed, and the results were compared with widely used solid fuels such as wood, coal, coke and charcoal. The heat values of biochar from tomato, tobacco, corn ZP 6263, and corn BC 398 stalks were 24.12, 23.09, 26.24 and 25.78 MJ kg-1, respectively. These values are significantly higher than the heat value of wood, which is about 12.50 MJ kg-1. The ash content of biochar was 12?20 %, which is consistent with the ash content of solid fuels. No heavy metals were found in biochar samples. The results show that biochar obtained from the pyrolysis of agricultural waste, such as tomatoes, tobacco and corn stalks, has good potential for use as a solid fuel.

Microwave pyrolysis of agricultural waste: Influence of catalysts, absorbers, particle size and blending components

The paper presents the results of experimental study of thermochemical conversion, phase transformations and chemical reactions during microwave pyrolysis of biomass (sawdust, straw, nutshells, rice husk, etc.). For the first time, the characteristics of the microwave co-pyrolysis of agricultural waste have been analyzed. The experiments aimed to register the yield of the main pyrolysis products (gas, char and bio-oil) by varying the following factors: type of biomass, particle size, type of absorber/catalyst, and composition of mixtures. The biomass particle size of 800 µm was optimal in terms of pyrolysis gas yield and quality. Pyrolysis of sawdust and straw had the maximum yield of combustible gas components in relation to CO2. The volumetric concentrations of CO, CH4, and H2 for these types of biomass were 20–70% higher than those for wheat bran, rice husk, and nut shell. Among the low-grade catalysts studied, carbon residue and charcoal were the most efficient in terms of maximizing combustible gas yield and reducing CO2. These catalysts reduced the bio-oil yield by a factor of 1.2 and increased the yield of combustible gases by a factor of 1.3. Pyrolysis of mixtures showed significant synergy, both positive and negative. The minimum yield of gas with the worst quality was typical for the mixture “rice husk 50%, sawdust 50%”. The maximum positive synergistic effects were recorded for the composition “rice husk 33%, sawdust 33%, and bran 33%”. The combination of these components increased the yield of CO, CH4 and H2 by 5–24%, 8–53% and 2–45%, respectively, compared to other mixtures. Thus, microwave co-pyrolysis creates great scope for the conversion of those components that do not provide the required gas characteristics during individual pyrolysis. Pyrolysis of mixtures contributes to the utilization of a large amount of plant waste while maintaining the quality of the end products.

Manure- and straw-derived biochars reduce the ecological risk of PBDE and promote nitrogen cycling by shaping microbiomes in PBDE-contaminated soil

Pyrolysis of agricultural waste into biochar for soil remediation is a useful solid waste management strategy. However, it is still unclear how different agricultural feedstocks affect the properties of biochars and their effectiveness in remediation of PBDE-contaminated soil. In this study, we systematically investigated dynamic alterations of soil properties, microbial communities, and PBDE dissipation and bioavailability induced by the application of biochars from manure (MBC) and straw (SBC) to PBDE-contaminated soil. The results showed that soil properties, microbial community structure, and diversity changed differently with the incorporation of the two biochars. MBC had a larger surface area (17.4 m2/g) and a higher nutrient content (45.1% ash content), making it more suitable for use as a soil additive to improve soil quality and nutrient conditions, as well as to stimulate microbial growth. SBC showed higher adsorption capacity for 2,2′,4,4′-Tetrabromodiphenyl Ether (BDE-47) (26.73 ± 0.65 mg/g), thus lowering the bioavailability and ecological risk of BDE-47 in soil. BDE-47 was stepwise debrominated into lower brominated PBDE by PBDE-degrading bacteria. MBC accelerated the debromination of BDE-47 (10.1%) by promoting PBDE-degrading microorganisms, while this was inhibited by SBC (3.5%) due to strong adsorption of BDE-47. In addition, we found that both types of biochar favored Nitrospirae bacteria and promoted N cycling. Overall, biochars from manure and straw can positively shape soil microbial communities differently by altering soil properties, soil fertility and nutrient availability, and the fate and the effects of contaminants, which ultimately led to a difference in the potential of biochars for their use in soil remediation.

Chemical Properties and Micromorphology of Biochars Resulted from Pyrolysis of Agricultural Waste at Different Temperature

Biochar quality is influenced by the type of its raw material and pyrolysis temperature. Nevertheless, the quality criteria of biochar as a nutrient carrier remain unanswered. This study aimed to find the chemical properties, micromorphology, and optimum pyrolysis temperature from various agricultural wastes to obtain good biochar as a nutrient carrier. This experiment was conducted at three level temperatures: 400, 500, and 600 ° C, and the raw materials were coconut shells, oil palm shells, and corn stalks. The chemical and physical properties of biochar were: pH-H 2 O, OC, CEC, total N, P, K, Mg, Ca, and Na, ash, functional groups, amorphous carbon, morphology, and SSA. The results show that the coconut shells and oil palm shells biochars contained high levels of N-total and the chain-C aromatic, and the pore structure was solid and regular. Corn stalks biochar containing ash is high, and C-aromatic is low and fragile. Increased temperature of pyrolysis produced well-crystallized minerals. It is concluded that 500°C is the optimum temperature for oil palm shells pyrolysis resulting in biochar with the highest C-aromatic structure and arrangement of pores which are strong, regular and uniform, and high stability, but the nutrient content was low.

Effect of heating rate and H3PO4 as catalyst on the pyrolysis of agricultural residues

This study reports the effect of heating rate and the addition of H3PO4 on the pyrolysis of three representative agricultural wastes of different lignocellulosic composition, namely pistachio shell, bitter orange peel, and saffron petal. Pyrolysis was carried out at 500 °C in a fixed-bed, lab scale reactor. Slow pyrolysis provided lower water contents in the liquid fraction. Fast pyrolysis increased the liquid yield for all the feedstocks, promoting the formation of phenolic, ketone/aldehyde compounds. It also enhanced the formation of water for all the agricultural residues. In addition, the energy content in the gas fraction is promoted due to a higher concentration of light hydrocarbons, methane, and hydrogen. However, when high inorganic matter is found in the feedstocks, the formation of CO2 is favored, hindering the energy improvement. The treatment of the biomass with H3PO4 significantly increased the solid fraction, producing a huge porosity development in the char (surface area over 1600 m2/g in pistachio shell product), at the cost of liquid fraction, which is mostly composed of water, with small amounts of acetic acid, phenol and toluene. The results pointed out that pyrolysis of agricultural waste can be targeted to achieve different products by switching pyrolysis conditions such as the heating rate and the treatment of the biomass with H3PO4.

REPLACEMENT OF COAL AND GAS WITH ALTERNATIVE SOURCES OF ENERGY

The work shows that agricultural waste can be an inexhaustible cheap source for green, renewable energy sources such as biocoal, biogas, high-quality organic fertilizer – biochar. The urgency of the problem has increased even more due to the need to replace fossil energy resources (coal, gas, oil), which used to come from Russia. The possibility of using exothermic heat of the process of pyrolysis of agricultural waste makes this process economically more attractive and will contribute to its implementation. When using the proposed pyrolysis technologies, all types of carbon-containing agricultural waste can be considered as an unclaimed resource for the decarbonization of the entire energy sector of Ukraine.

EFFECTS OF WOOD ASH ON GEOTECHNICAL PROPERTIES OF LATERITIC SOILS

Biochar can be derived from pyrolysis of agricultural waste, wood waste (saw dust), logging residues and other biological waste. Biochar can be use to improve the quality of construction and engineering materials. The study deals with the effect of biochar (wood ash) on geotechnical properties of lateritic soils, and it is to investigate the effect of wood ash on the geotechnical properties of lateritic soils. For these purpose, soil samples that were gotten from borrow pit were made use of and blended with available biochar which is used as a stabilizing agent. This was done at different percentages which include (0%, 3%,5%, 10%,15% and 20%,). The biochar was sieved with 125 micrometer sieve and were after blended with the soil samples. The compaction test, consistency limit test, the unconfined compressive strength test were carried out on the samples. It was discovered that the OMC of the blended samples increases as the percentages of the biochar that was used to blend the samples increases, also the MDD on the contrary decreases. The unconfined compressive strength test were conducted on all the samples (0%,3%,5%,10%,15% and 20%). It was also discovered that the compressive strength of soil samples increases with increase in the addition of biochar of the samples having its peak at 10%. Then reduction in compressive strength was experienced in between 11% to 20% addition of biochar to the soil sample. Conclusively, the results show that biochar can be use as stabilizing material when added to lateritic soil samples. But more addition of it at a particular stage may lead to the reduction in the compressive strength of the sample in which the sample may be weak and brittle. The size of the biochar if not properly crushed and sieved may not yield a desired result.

Effect of biochar use as a substrate on granadilla (Passiflora ligularis Juss.) growth parameters

The impact of biochar on soils has been demonstrated, including its improvements of physical, chemical, and biological properties that promote agricultural production. This study aims to evaluate the effect of biochar on the growth of granadilla (Passiflora ligularis Juss.) seedlings. For this research, biochar was obtained from the pyrolysis of agricultural waste in a conical flame curtain reactor at temperatures between 400ºC and 500ºC for 90 min. The different biomasses used consisted of cholupa (Passiflora maliformis L.) fruit shells, residues of guamo (Inga spuria) wood, coffee (Coffea arabica L.) husks, and rice (Oryza sativa L.) husks. The biochar produced was mixed with Jiffy® brand peat in doses of 5%, 10%, and 20% (v/v) for each of the four types of biochar, with a control of 100% peat. For each treatment, 100 seedlings were planted, taking 12 random samples of each at 43, 57, and 71 d after sowing. Data were analyzed using the Kolmogorov-Smirnov and Levene test, followed by a factorial analysis of variance, evaluating variables such as dry weight, root length, leaf number, stem diameter, and chlorophyll index. The biochar obtained from the coffee husk promoted further growth, but its effectiveness decreased at a concentration of 20%.

Sonocatalytic degradation of ciprofloxacin using hydrogel beads of TiO2 incorporated biochar and chitosan

Pharmaceuticals are necessary to be removed from environment. Herein TiO2 incorporated biochar made from pyrolysis of agricultural wastes was encapsulated into chitosan to obtain a novel hydrogel beads. This hydrogel beads executed a dual role as both adsorbent and sonocatalyst, which proved to be suitable for the removal of antibiotic ciprofloxacin (CIP) from water. The results showed that adsorption of CIP followed pseudo first order kinetics model and Langmuir adsorption isotherm model, having maximum adsorption at pH 9. Whereas the degradation was more efficient at pH 6 due to greater standard potential for •OH/H2O in acidic media. The degradation was maximum at 150 W of ultrasonic power, then decreased in presence of dissimilar electrolytes and even reduced to 0 in presence of Na3PO4. Different quenchers such as benzoquinone (BQ), Triethanolamine (TEA) and isopropyl alcohol (IPA) reduced degradation efficiency (DE) and mineralization efficiency (ME). The DE was decreased from 85.23% to 81.50% (BQ), 74.27% (TEA), and 61.77% (IPA) within 25 min. The prepared sonocatalyst was capable of regeneration with DE, remaining sufficiently high (62%) even after four regeneration steps. These results indicate that titanium-biochar/chitosan hydrogel beads (TBCB) are durable and effective for long-term CIP removal.

CO-PYROLYSIS of agricultural waste and estimation of the applicability of pyrolysis in the integrated technology of biorenewable hydrogen production

For the production of biorenewable hydrogen, the possibility of pyrolysis of agricultural waste, namely cow manure (CM) and stems of weed Amaranthus retroflexus L. (AR), as well as their mixtures in a ratio of 1:1, 2:1 and 4:1, was investigated. Thermogravimetric analysis was carried out at a heating rate of 10 °C/min in the temperature range from 40 °C to 1000 °C. It was shown that the thermal decomposition of agricultural waste in an inert environment is characterized by three main stages, the most significant of which is in the temperature range from 145 to 410 °C, at which the maximum yield of volatile components occurs. Pyrolysis was carried out at a temperature of 550 °C and a heating rate of 10 °C/min. During the pyrolysis of CM and AR mixture, the material balance was on average as follows: 36.95% pyrolysis liquid, 24.99% syngas and 38.06% biochar, and the maximum hydrogen concentration in the pyrolysis gas was 21.17% with CM to AR ratio of 4:1. With this ratio, the hydrogen yield was 12.1% higher than when using a mixture of CM and AR with a 1:1 ratio. An increase in the proportion of AR in the mixture led to the enrichment of the pyrolysis liquid with phenolic compounds. The obtained high content of fixed carbon (47.52%) in biochar is attractive for its use as soil additives. For further research on increasing the yield of gaseous hydrogen from biomass, a scheme of bio-thermochemical processing was proposed, involving a combination of dark fermentation and pyrolysis.

Pyrolysis of agricultural waste in a thermogravimetric analyzer: Studies of physicochemical properties, kinetics behaviour, and gas compositions

Biomass is employed in pyrolysis to generate a substance that can be employed as a feedstock for speciality chemicals as well as a source of energy. Since the oil crisis in the middle of the 1970s, significant progress has been made to transform biomass into liquid fuels and chemicals. To make the process more efficient and optimized, kinetic understanding is required before moving on to applied pyrolysis. Thus, the present study explored the pyrolysis kinetics of low-value agricultural waste biomass at varied heating rates in a thermogravimetric analyzer (TGA). Six model-free methodologies were utilized to analyse the kinetics parameters (Kissinger-Akahira-Sunose (KAS), Ozawa-Flynn-Wall (FWO), Distributed Activation Energy Model (DAEM), Coats-Redfern (CR), Vyazovkin model (VZ), and master plot). In addition, a TGA-FTIR analyzer was employed to investigate the gas composition online. The physicochemical study’s findings suggested that it could be used as a feedstock for pyrolysis in the bioenergy sector. Furthermore, TGA-FTIR analyzer established the highest discharge of CO2 (28.73 and 33.14 %) and carbonyl products (20.60 and 29.35 %) for WS and CS, respectively. The average apparent activation energies (AAAE) for KAS, OFW, DAEM, and VZ are also determined to be 237.12, 186.40, 170.50, and 163.63 kJ mol−1 for WS and 176.37, 170.51, 196.12, and 194.91 kJ mol−1, for CS respectively. Further, the master plot and thermodynamic study of biomass exposed that pyrolysis passed through many multifaceted reaction mechanisms (Diffusion, nucleation, phase boundary-controlled etc.) during pyrolysis. Overall, pyrolysis techniques can be used to increase the energy density of lignocellulosic residues in an environmentally friendly manner.

Fast Pyrolysis of Flax Shive in a Screw‐Type Reactor

AbstractA novel screw‐type reactor for the fast pyrolysis of agricultural waste (flax shive) is described. A preliminary study on the influence of process parameters on the yield, composition, and properties of pyrolysis products was carried out. Based on the results obtained, the optimal conditions of fast pyrolysis of flax shive particles in terms of feedstock particle size, solid residence time, and process temperature were identified. Considering the construction, the developed reactor seems to be close to the screw fluidized bed and auger reactor and is characterized by a simple design and operation control. Moreover, the proposed reactor can be used for continuous pyrolysis without any significant modification.

A Review Pyrolysis: Different Agricultural Residues and Their Bio-Char Characteristics

Due to the large availability of biomass resources, India has great potential for the production of biochar. Different types of thermochemical even biological processes have been adopted to convert biomass into value‐added products. Among those processes, pyrolysis is more convenient since it has several advantages of storing, transportation, and flexibility in solicitation such as turbines, combustion appliances, boilers, engines, etc. Fig. 1 Overview of the pyrolytic product. Illustrates different types of the existing biomass conversion process with their respective output. The study was undertaken to investigate the properties of various agricultural residues. Until recently, the use of BC (biochar) in agriculture was mainly focused on the application of BC as a soil amendment. However, there are opportunities to investigate in this wide field of study, as there are plenty of potential relationships between various parameters, such as (but not limited to) BC(biochar) feedstock material, dose, and its characteristics, type of soil, plant species, and target elements/compounds of the treatment. Other related aspects that were investigated are BC‐enhanced composting processes and obtaining the BC via pyrolysis of agricultural waste.

Eco-friendly production of biochar via conventional pyrolysis: Application of biochar and liquefied smoke for plant productivity and seed germination

Abstract Conventional pyrolysis of agricultural wastes may emit considerable amounts of greenhouse gases that affect negatively the surrounding environment. A trial was done to capture the emitted gases through connecting a small water jacket with the pyrolysis unit. This plant was then used for production of biochars from two waste materials i.e. nutshell (NS-BC) and date-palm seed (DP-BC). The biochars manufactured from the aforementioned waste materials were then evaluated for their applicability vs pig manure (each amendment was applied at rates of 1, 2.5, 5 and 10%; w/w) to improve growth of Brassica chinensis grown on a sandy soil under greenhouse conditions. Collected liquefied smokes were also tested for enhancing germination of Lactuca sativa (lettuce) seeds using different concentrations (0%–5%, v/v). Results revealed that produced biochars decreased significantly soil pH where the highest reduction (14.30%) was occurred due to addition of 10% DP-BC. Moreover, NS-BC and DP-BC decreased significantly soil salinity from 0.21 dS m −1 (control) to 0.13 and 0.14 dS m −1, respectively; on the other hand, pig manure raised significantly soil salinity (10% application rate). Residual organic matter was higher in biochar amended soils than its corresponding values in pig manure treated ones. Generally, all investigated amendments improved considerably the uptake of nitrogen, phosphorus, and potassium. Moreover, they increased chlorophyll pigments in leaves and enhanced plant growth parameters upon their application at rates up to 2.5% with superiority for NS-BC versus DP-BC. Liquefied smoke also improved lettuce seed germination and growth, but only up to 0.25% application rate. Our results highlighted the success of the adopted technique for recycling NS and DP wastes and sustaining the environment.

Coconut husk biochar amendment enhances nutrient retention by suppressing nitrification in agricultural soil following anaerobic digestate application.

Anaerobic digestate and biochar are by-products of the biogasification and pyrolysis of agricultural wastes. This study tested the hypothesis that combined application of anaerobic pig/cattle manure digestate and coconut husk (CH) biochar can improve soil nutrient conditions, whilst minimizing atmospheric and groundwater pollution risks. Microcosms simulated digestate application to agricultural soil with and without CH biochar. Ammonia volatilization and nutrient leaching were quantified after simulated heavy rainfalls. Archaeal and bacterial community and abundance changes in soils were quantified via next generation sequencing and qPCR of 16S rRNA genes. Nitrifying bacteria were additionally quantified by qPCR of functional genes. It was found that CH biochar retarded nitrate leaching via slower nitrification in digestate-amended soil. CH biochar reduced both nitrifying archaea and bacteria abundance in soil by 71–83 percent in the top 4 cm soil layer and 66–80 percent in the deeper soil layer one month after the digestate application. Methanotroph abundances were similarly reduced in the CH biochar amended soils. These findings demonstrate combined benefits of anaerobic digestate and CH biochar application which are relevant for the development of a more circular rural economy with waste minimization, renewable energy production, nutrient recycling and reduced water pollution from agricultural land.

A study of fast pyrolysis of plant biomass assisted by the conversion of volatile products using Fe(Co, Ni)/ZSM-5 catalysts

AbstractThis paper discusses the study of plant waste thermocatalytic conversion. The dependence of the conversion of agricultural waste on the pyrolysis temperature, reaction time and feedstock particle size was determined. The optimal temperature of fast pyrolysis providing the highest yield of gaseous products (over 30 wt. %) for all types of waste plant biomass was found to be 700 ºC. This temperature allows the lowest tar content in gases to be obtained. Further, ZSM-5 synthetic zeolites modified with iron subgroup metals were studied in the conversion of volatile products obtained by the fast pyrolysis of agricultural waste. It was found that the use of zeolite-based catalysts in the upgrading of gaseous products leads to a decrease in tar content and the increase in the volume concentration of С1-С4 hydrocarbons, CO, CO2, and hydrogen in comparison with the non-catalytic process.

Agri‐food waste valorisation

Agri‐food waste valorisation

A Review of Biochar Properties and Their Utilization in Crop Agriculture and Livestock Production

When it comes to the use of biochar in agriculture, the majority of research conducted in the last decade has focused on its application as a soil amendment and for soil remediation. This treatment improves soil quality, increases crops yields, and sequestrates atmospheric carbon to the soil. Another widely studied aspect connecting biochar with agriculture is the composting processes of various agricultural waste with the addition of biochar. Obtaining the material via the pyrolysis of agricultural waste, including animal manure, has also been investigated. However, given the remarkable properties of biochar, its application potential could be utilized in other areas not yet thoroughly investigated. This review paper summarizes the last decade of research on biochar and its use in crop agriculture and livestock production. Knowledge gaps are highlighted, such as using biochar for the mitigation of odorous emissions from animal manure and by feeding the biochar to animals.

Impact of pyrolytic carbonaceous nano inerts addition on fracture and electromagnetic interference shielding characteristics of cementitious composites

The fragile behavior of traditional cementitious composites can be tweaked by reinforcing the matrices at nano scale via intrusions of carbonaceous inerts. However, high fabrication cost of these inerts barred their extensive industrial application. In the present study, cost-effective carbonaceous nano-inerts were synthesized via pyrolysis of agricultural wastes in the form of wheat straw and cotton stalk at a temperature of 500 °C in an inert environment. Carbon rich solid residue obtained from pyrolysis was milled to nano size and characterized through energy dispersive X-ray spectroscopy, X-ray diffraction analysis, thermogravimetric analysis, Fourier transform infrared spectroscopy and Raman spectroscopy. Synthesized carbonaceous nano-inerts from wheat straw and cotton stalk have been intruded in to cementitious matrix for the first time in the best knowledge of author, to enhance its fracture characteristics and electromagnetic interference shielding effectiveness. Cement mortar specimens were prepared with the intrusions of carbonaceous nano-inerts by 0.025, 0.05, 0.08, 0.2, 0.5 and 1 wt% of cement in addition mode, after being effectively dispersed in water. Three point bending tests were performed on notched prisms at a very sensitive strain rate of 0.003/min in strain controlled mode with the broken halves analyzed for resistance in compression. Substantial increase of 59.8% in fracture toughness and 44.5% in compression was attained with the addition of 1% carbonized cotton stalk and 0.5% carbonized wheat straw respectively. Moreover, scanning electron micrographs have verified the involved strengthening mechanisms encompassing crack branching, pinning and crack bridging via intruded nano-inerts. Furthermore, shielding against electromagnetic interference was tested in X-band frequency range of 8–12 GHz and maximum improvement of 23.5db and 22.9db was attained with intrusion of carbonized wheat straw and carbonized cotton stalk nano particles respectively.