Catalytic Pyrolysis Of Biomass Research Articles

Biogenically synthesized aluminum oxide nanoparticles via phyllanthus emblica seeds for photocatalytic applications

In this study, Phyllanthus emblica (amla) seed extract was employed to biosynthesize Aluminum oxide nanoparticles (Al2O3 NPs) as efficient stabilizers and bio-reducing agents. The successful synthesis of Al2O3 NPs was confirmed and characterized by UV–Vis spectroscopy (UV/Vis), Fourier Transform Infrared Spectroscopy (FT-IR), scanning electron microscopy (SEM) and X-ray diffraction spectroscopy (XRD). Antibacterial activity of these environmental friendly Al2O3 NPs was evaluated through a disk diffusion method, demonstrating their potential as antimicrobial agents against pathogens, including gram-positive and gram-negative bacteria. Additionally, Al2O3 NPs exhibited substantial photocatalytic activity, achieving a remarkable 95.06% degradation of 4-nitroaniline (4-NA) under UV light irradiation. Furthermore, Al2O3 NPs served as efficient catalysts in catalytic biomass pyrolysis, boosting bio-oil yields by 47.4%. The resulting bio-oil was analyzed using FT-IR spectroscopy. This research emphasizes the significance of biomass waste in producing biofuel as well as disinfection and environmental remediation applications, offering sustainable solutions for various challenges.

Production of monocyclic aromatic hydrocarbons by the catalytic pyrolysis of Moso bamboo at different ages and parts using Zn and Cr modified zeolite catalysts

Monocyclic aromatic hydrocarbons (MAHs) are important organic building blocks for the chemical industry, which can be produced by catalytic pyrolysis of biomass. The wide application of bamboo in Chinese industry generates a large amount of bamboo waste which can be utilized as the feedstock to produce MAHs. This study aimed to investigate the effect of bamboo age and bamboo part on the yield of the aromatics by using the Cr and Zn modified HZSM-5 as catalyst. The result showed that the incorporation of metals (Cr and Zn) enhanced the catalytic performance, and the incorporation of Zn was better than Cr. The highest MAHs content (38.67%) and total aromatic content (57.42%) were obtained with the catalyst of 3% Zn/HZSM-5 catalyst at temperature of 400 °C and duration time of 30min. Younger age (1-year-old bamboo) and the outer skin of bamboo was better for the production of MAHs. This study provided a high value-added application approach for the waste Moso bamboo.

Catalytic pyrolysis of wood dust for monophenol over macroalgal biochar-based catalyst: Effects of activation agents and atmospheres during catalyst synthesis on its performance

After introducing heteroatoms into the carbon material skeleton, the performance of carbocatalyst during catalytic pyrolysis of biomass for monophenol production is significantly improved. Algae, as a carbon source with intrinsic nitrogen content, is well-identified as a suitable raw material for preparing heteroatom-doped carbocatalyst. The present study aimed to investigate the effects of different alkaline activation agents (KOH/NaOH) and gas atmospheres (N2/CO2) during the carbonization-activation synthesis process of macroalgal biochar-based catalysts (MBBCs) on their properties and performances. Characterizations of carbocatalysts were carried out via BET and XPS analyses to investigate the porous structures and surface functional groups. Results showed that CO2, as a weakly oxidizing atmosphere, can promote the formation of porous structure of MBBCs. However, the promotion is not as strong as that of chemical activation agents (KOH/NaOH). Furthermore, KOH can promote the formation of porous structure more strongly than NaOH, but NaOH can substantially enhance the formation of surface oxygen‑nitrogen groups compared to KOH. All the MBBCs exhibited the increment of monophenols in the bio-oil obtained from catalytic pyrolysis of wood dust, especially phenol, o-cresol, and p-cresol. Amongst, the biochar-based catalyst activated with NaOH in CO2 atmosphere was the most effective one in promoting monophenols content (up to 59.46 %). Compared with the control group (without catalyst), the phenol content was increased from 5.03 % to 19.40 %. Moreover, it is found that the catalytic performance was positively correlated with the CO species percentage on the surface of MBBCs. The macroalgal biochar-based catalyst has an excellent catalytic performance, which is of great significance for achieving the complete utilization of algae and thereby improving the quality of catalytic pyrolysis products.

Coke formation on different metal-modified (Co, Mo and Zr) ZSM-5 in the catalytic pyrolysis of cellulose to light aromatics

Catalytic pyrolysis of biomass is regarded as a promising method for preparing value-added products. However, the main factors limiting the development of the process at present are the low yield of value-added products and poor selectivity, especially for rapid catalyst deactivation due to coke deposition. The present study focuses on the catalytic pyrolysis of cellulose over metal Co-, Mo-, and Zr-loaded catalysts using a falling fixed bed at 600 °C to evaluate the type of coking of the catalysts as well as the effect of the different metal active sites on the formation of coke deposits. The introduction of Co and Mo metal sites increased the light aromatics yield of ZSM-5 from 128.9 mg/g to 147.2 mg/g and 143.0 mg/g. And the yield of coke deposits decreased from 8.3 to 6.8 and 5.1 wt%. The stability evaluation of the catalyst showed that the deactivation degree of ZSM-5 of the supported metal Co was lower than that of commercial ZSM-5, while the ZSM-5 of the supported metal Mo was rapidly deactivated. The deactivation of the catalysts depended more on the morphology or location of the accumulated coke than on the total amount deposited. The clogging of metal and acidic sites on the surface of the zeolite and the pore channels by the amorphous encapsulating coke was the main cause of catalyst deactivation. The metal Mo active sites promoted dehydrogenation coupling and hydrogen transfer during coke formation, forming a more highly disordered multiring structure, and the metal Co active sites were more capable of decomposing macromolecular compounds, olefins and alkanes, and promoted the formation of graphite-like structural carbon.

One-dimensional biomass-based carbon nanotubes loaded with MoS2 as catalysts for the electrocatalytic nitrogen reduction reaction

In recent years, electrochemical conversion of nitrogen to ammonia at low temperature and atmospheric pressure has become a hot research topic because of its advantages of low carbon emission, low energy consumption and high energy transfer rate. The development of catalysts with high catalytic activity and flexibility are an important topic in the current nitrogen reduction reaction. In this paper, CNT@MoS2 composite catalysts were prepared by catalytic pyrolysis of biomass to prepare one-dimensional carbon nanotubes and then combined with MoS2 by a hydro thermal method. It was found that 120 CNT@MoS2 had better NRR activity and selectivity, NH3 yield rate of 21.2 μg h−1 mg−1 was achieved at −0.44 V vs. The Faraday efficiency can reach 5.4%. The catalytic performance is more than 3 times higher than CNT. The mechanism of MoS2-catalyzed NRR was further investigated by DFT theoretical calculations. The results of the theoretical calculations are in good agreement with the experimental results, providing a reasonable explanation for the high reduction performance of the catalyst. This study offered a promising avenue for exploring and rationalizing the design of electrocatalytic materials for NRR.

Characterization of the decomposition behaviors of catalytic pyrolysis of alkaline lignin with the addition of different concentrations of potassium

Investigating the influence of potassium concentration on alkali lignin pyrolysis is beneficial for advancing the technology of biomass catalytic pyrolysis. This study examined the catalytic effects of different concentrations of various potassium compounds on alkali lignin pyrolysis. The impregnation method was employed to load potassium compounds (KCl, K2CO3, and CH3COOK) onto alkali lignin at varying concentrations. The results showed a significant influence of potassium concentration on the catalytic pyrolysis of lignin. Increasing the potassium concentration resulted in higher pyrolysis char yield and lower pyrolysis gas yield. Furthermore, the pyrolytic char with a high concentration of potassium exhibited a distinct surface pore structure that was noticeably eroded by potassium. Furthermore, with an increase in potassium concentration, the removal of side chains, including methoxy, acetyl, and hydroxyethyl groups, became increasingly pronounced, resulting in higher yields of CO2 and phenol. The elevated potassium concentration facilitated the depolymerization of lignin through Cβ-O bond cleavage, promoted the decomposition of intermediate products, and enhanced the formation of small molecule products. Ultimately, a hypothetical mechanism explaining the influence of potassium concentration on alkali lignin pyrolysis was proposed. This study establishes a scientific foundation for the high-value utilization and resource development of alkaline lignin.

Catalytic pyrolysis of biomass to aromatics over bifunctional Ni/ZSM-5 catalysts assembled on rice husk-derived silica platform

Catalytic pyrolysis of biomass to aromatics over bifunctional Ni/ZSM-5 catalysts assembled on rice husk-derived silica platform

A novel three-stage ex-situ catalytic pyrolysis process for improved bio-oil yield and quality from lignocellulosic biomass

This study aims to improve the quality and yield of bio-oil produced from ex-situ catalytic pyrolysis of lignocellulosic biomass (sawdust) using a combination of stage catalysts with Al-MCM-41, HZSM-5, and ZrO2. The research employed various methods, including thermogravimetric analysis (TGA), differential scanning calorimetry, bench-scale experiments, and process simulations to analyze the kinetics, thermodynamics, products, and energy flows of the catalytic upgrading process. The introduction of ZrO2 enhances the yield of monoaromatic hydrocarbons (MAHs) in heavy organics. Compared with the dual-catalyst case, the MAHs yield escalates by approximately 344% at a catalyst ratio of 1:3:0.25. Additionally, GC-MS data indicate that the incorporation of ZrO2 promotes the deoxygenation reaction of the guaiacol compound and the oligomerization reactions of PAHs. The integration of ZrO2 as the third catalyst enhances the yield of heavy organics significantly, achieving 16.85% at a catalyst ratio of 1:3:1, which increases by nearly 35.6% compared to the dual-catalyst case. Also, the addition of ZrO2 as the third catalyst enhanced the energy distribution in heavy organics. These findings suggest that the combination of these catalysts improves the fuel properties and yields of the bio-oil.

Impact of Na at the low temperature Fe catalysis on high quality cellulose-based graphitic carbon

Biomass-based graphitic carbon is a promising material, but the effect mechanism of inherent alkali metals on the catalytic pyrolysis of biomass is still unclear. In this study, cellulose was selected as the model substance, and the influence mechanism of Na on the graphitization of cellulose catalytic pyrolysis was investigated through a combination of experiments and theoretical calculations. The results indicate that Na can interact with the carbon skeleton through van der Waals forces, thereby altering the spatial structure of graphite crystals and increasing the interlayer spacing of graphite by 27.7%. In addition, Na can coexist with Fe(III) in the form of oxides, while also increasing the reaction energy barrier of reverse hydroxylation and dehydration cyclization, decreasing the generation of reducing gases mainly composed of CO. This impedes the reduction of iron-based catalysts, thereby affecting the formation of the graphite microcrystalline structure. The research indicates that maintaining the ratio of Na content to iron-based catalysts within a 1:1 range is optimal for producing graphite carbon from cellulose.

Augmenting levoglucosan production through catalytic pyrolysis of biomass exploiting Ti3C2T MXene

Augmenting levoglucosan production through catalytic pyrolysis of biomass exploiting Ti3C2T MXene

Enhancement of aromatics and syngas production by co-pyrolysis of biomass and plastic waste using biochar-based catalysts in microwave field

In this study, O-rich biomass (bamboo) was co pyrolyzed with H-rich plastic waste (PE) based on the biochar-based catalysts to investigate the yield and quality of pyrolysis oil and syngas. Focusing on the variations of aromatics and phenolics, to reveal the synergetic mechanism between biomass and PE in microwave field. Biomass is “rich in O and lack of H″, and waste plastics are “rich in C and rich in O″ which can provide a lot of H radicals for catalytic pyrolysis of biomass, improve the quality of bio-oil. And the active factors of biomass effectively activated PE. The biochar-based catalysts further promoted deoxygenation and arylation reactions, intensifying the generation of aromatics and reducing oxygen-containing compounds (phenols, etc.). Bamboo: PE = 1: 3 catalyzed by Zr-modified biochar-based catalysts resulted in aromatics yielded as high as 74.13%, while phenols yields was only 9.39%. Incorporation of the externally H-donor PE promoted the growth of carbon chains, and the microwave field activated free radicals which facilitated the cyclization and arylation of carbon. The biochar-based catalysts also promoted the generation of high-value monocyclic aromatics by utilizing the selective ability in the microwave field. Finally, the coupled synergistic mechanism of co-pyrolysis in microwave field was proposed.

In-situ bio-oil directional conversion mechanism of catalytic biomass pyrolysis over nitrogen-doped carbon preparation by grading of nitrogen-rich cow dung

N-doped carbon catalysts were prepared using corn straw (CS) and cow manure (CD) as carbon and N resources, and used for the CS catalytic fast pyrolysis in Py-GCMS to improve the quality of bio-oil products. Through the methods combining hydrothermal treatment and carbonization, the N from CD was efficiently fixed into the straw biochar, showing the better catalytic effect. The moderate carbonization temperature (600 °C) and the lower HTC temperature benefited the improvement of N-doped biochars on the relative content of phenols in bio-oil, with the maximum increment of 8.32%. The pyridinic-N and pyrrolic-N in N-doped biochars mainly enhanced the relative content rather than the yields of phenols and ketones, respectively. Compared with the surface area and the degree of disorder, the types and content of N species in N-doped biochar had the greater promoting effect on the relative content of phenols in bio-oil.

Catalytic pyrolysis of biomass to produce bio‐oil using layered double hydroxides (LDH)‐derived materials

AbstractOwing to the enormous consumption of petroleum products and their environmental polluting nature, attention has been given to seeking alternative resources for the development of sustainable products. Biomass is a renewable source that can be converted to a variety of fuels and chemicals by different approaches, which are the best replacements for traditional petroleum‐derived products. Pyrolysis is a process in which chemical bonds of biomass macromolecules such as cellulose, hemicellulose, and lignin, are fractured into small molecular intermediates under high pressure, and results bio‐oil, biochar, and fuel gases as desired products. Of these pyrolysis products, bio‐oil is the primary product that usually contains large amounts of oxygen and nitrogen compounds that hinder its application potential. Catalytic pyrolysis is a beneficial method that is reported to alter the constituents and quality of bio‐oil and to upgrade them for diverse applications. Catalytic hydropyrolysis and copyrolysis of biomass are an alternative approaches to overcome the drawbacks raised toward product formation in the pyrolysis process. Layered double hydroxides (LDH) and their derived forms are well‐known catalytic/catalytic support materials for various chemical reactions due to their superior properties, such as easy preparation, thermal stability, and tuneable acid/base properties. This review summarizes the progress in the utilization of as‐synthesized LDH and their modified forms such as mixed metal oxides and functionalized/composite materials as active catalysts for the pyrolysis of various biomass sources.

Char-based Fe-Ni-Ca material for capturing AAEM from biomass pyrolysis volatiles and recyclability in catalytic reforming of volatiles

Hydrogen production derived from biomass catalytic pyrolysis has received increasing attention, to solve the excessive consumption of renewable energy. However, considerable amounts of the issues (e.g., slag formation, corrosion, and scaling on the heat exchange surface) related to alkali and alkali earth metals (AAEM) have hindered its application. To address these challenges and improve the yield of H2, char-based Fe-Ni-Ca material is proposed to capture AAEM from biomass pyrolysis volatiles while increasing the H2. Char-based materials exhibit excellent AAEM capture ability, with K, Na, and Mg contents detected in spent materials being 3.4 times, 1.4 times, and 1.5 times higher than those in fresh, respectively. Besides, the spent Fe-Ni-Ca exhibits excellent stability after regeneration, with H2 production comparable to that of fresh material, and CO production exceeding that of fresh Fe-Ni-Ca. It was disclosed that the char support can adsorb AAEM in volatiles, and then chemical reactions will occur between metal elements (Fe, Ni, and Ca) in the material and AAEM in the volatiles, trapping AAEM in the material and catalytic reforming volatiles. This work provides a novel strategy to deal with AAEM in volatiles.

Characteristic analysis and kinetics description for biochar-based catalysts coking during the biomass catalytic pyrolysis

Coke formation is one of the major obstacles in the development of catalytic pyrolysis of biomass. The experiments were carried out on poplar wood chips using the biochar-based catalysts (poplar biochar: ZSM-5 = 1:2) to study the coke formation characteristics of biochar-based catalysts and to develop the kinetic models of coke formation. It is shown that the high temperature and long reaction time promoted the conversion of carbon from amorphous coke to graphitized coke. The higher the degree of graphitization of the coke, the higher the combustion temperature and the richer the cyclized structure. Activated coke and neutral coke were gradually converted to inert coke per unit mass of catalyst. Based on the experimental data, combined AIC evaluation system, it is found that the MMCGM (monolayer-multilayer coke growth model) can only describe the coke formation at low temperature well. Therefore, the kinetic model of carbon particle stacking model was established. This model can well describe the coke formation process on biochar-based catalysts. This study is expected to provide a guide for understanding the characteristics of catalyst coke formation and optimizing pyrolysis conditions and reactors.

Eco-friendly synthesis of copper oxide nanomaterial by using Musa paradisiaca leaves extract and their slow pyrolysis or catalytic reduction activities

Copper oxide nanoparticles (CuO NPs) have been prepared via sol-gel synthetic approach using aqueous leaves extract of Musa paradisiacal and copper chloride dehydrate salt. UV visible spectroscopy showed maximum peak for CuO NPs at 535 nm. Additionally, the SEM XRD techniques confirmed spherical shape of CuO NPs with average size of 15 nm. Nitro compounds have been carefully chosen as a tested contaminant to study performance of CuO NPs. Catalytic reduction of nitro compounds was investigated under different temperatures to evaluate thermodynamic studies. According to the results, catalytic reduction of nitro compounds obeys Langmuir–Hinshelwood mechanism. The value of apparent rate constant shows a linear trend with catalyst concentration. The catalytic pyrolysis of corncob biomass in the presence of CuO NPs showed more bio-oil (46.13 %) yield as compared to ZSM-5 (40.07 %) and without catalyst (37.09 %) reactions. The data also confirmed that CuO NPs showed excellent performance as a micro-reactor for catalytic degradation of nitro compounds and catalytic pyrolysis. The CuO NPs have been isolated and reused in 5 consecutive cycles with good and reproducible excellent performance.

Synthesis of multifunctional porous carbon-silicon composites from coal gasification fine slag: Adsorption of methylene blue and microwave-induced biomass catalytic pyrolysis

Coal gasification fine slag (CGFS) is an important byproduct in the coal gasification process with a huge annual output in China and its efficient and green conversion is one of the key issues in the development of coal chemical technology. In this study, using CGFS as the raw material, a facile method was designed for the preparation of multifunctional porous carbon-silicon composites through one-step alkali fusion based on its carbon, silicon and metal elements composition. It was found that the reaction proceeded more adequately using KOH as the activator and the obtained material (T-K1) was mainly composed of micropores and mesopores. A great number of prismatic nepheline crystals were formed and embedded in the honeycomb porous carbon. The specific surface area of T-K1 reached 424.33 m2/g with a variety of active functional groups on the surface. The porous composite exhibited great potential as a multifunctional adsorbent and catalyst. Using T-K1 as an adsorbent, its equilibrium adsorption capacity on methylene blue (MB) reached 208.44 mg/g at 298 K. The adsorption process was consistent with the situation described by the pseudo-second-order kinetic and the Langmuir model, and the adsorption mechanism mainly originated from cation exchange, van der Waals forces, π-π interaction, hydrogen bond and electrostatic attraction. In addition, T-K1 can act as both a catalyst and a microwave absorber in the microwave pyrolysis of biomass. Taking pine sawdust as an example, H2 and CO in the gas product were enriched with high yields of 126.4 and 178.9 ml/g at 550 °C respectively, and the relative content of the phenolic in bio-oil increased to 53.6%. It is believed that this process can provide a useful alternative for the high-value-added transformation of solid waste containing carbon and silicon.

Research on the application of catalytic materials in biomass pyrolysis

Biomass, as a very important renewable resource, its efficient conversion was an important way to achieve zero CO2 emissions, provide clean and renewable energy, and promote the resource utilization of agricultural waste. Biomass pyrolysis, as a technology that could simultaneously obtain high value-added energy and chemical products such as biochar, bio-oil, and combustible gas, had received widespread attention, in which the role of catalysts in biomass pyrolysis had also been widely studied. In this thesis, the application of catalysts in biomass pyrolysis was reviewed in detail on the basis of introducing the principle and pyrolysis methods of biomass pyrolysis, and found that catalysts could effectively improve the distribution and properties of pyrolysis products, especially for the reforming of bio-oil and bio-gas, which had shown outstanding performance in green energy and functional chemicals. At the same time, the current problems of catalysts in biomass pyrolysis were analyzed, and new thoughts were proposed for future research on biomass catalytic pyrolysis, with a view to providing new ways for efficient catalytic pyrolysis and green sustainable development of biomass.

Investigating the synergistic driving action of microwave and char-based multi-catalysts on biomass catalytic pyrolysis into value-added bio-products

A method for preparing value-added bio-products dominated by aromatic hydrocarbon bio-oil with high selectivity by fast pyrolysis of biomass under the synergistic effect of microwave and char-based multi-catalysts (CMCs) was proposed. Various CMCs were prepared, and their structural characteristics were compared in detail. Microwave pyrolysis (MWP) experiment shows that the synergistic of microwave and biochar (hot spot effect) activates the active sites of molecular sieve catalysts, which can improve the diffusion of heavy components, thus regulating the pyrolytic products. Two non-noble metal active sites were introduced into CMCs, and their pyrolysis characteristics were compared. The Zn-modified CMCs showed good selectivity to monocyclic aromatic hydrocarbons. The yield of monocyclic aromatic hydrocarbons (MAHs) increased to 28.49 %, and the content of C6 ∼ C8 aromatic hydrocarbons was obviously increased, especially in the decarbonylation reaction. The Zr-modified CMCs could inhibit the transition condensation and cyclization of aromatic hydrocarbons. The ratio of MAHs to polycyclic aromatic hydrocarbons (PAHs) reached 1.31–1.42, which optimized the distribution of liquid products, and the yield of MAHs was between 22.99–28.61 %. CMCs have the characteristics of microwave absorption and catalytic conversion of aromatic hydrocarbons with high activity.

Synthesis of alkoxyphenols-rich bio-oil by microwave-assisted catalytic pyrolysis of wood over MoS2 catalyst

Microwave-assisted pyrolysis (MAP) is widely concerned as a high-efficiency treatment of forestry solid waste to produce value-added products. In this study, alkoxyphenols-rich bio-oil was selectively produced from wood powder through MAP process using self-made MoS2 catalysts. First of all, the yield of bio-oil was selectively controlled by changing the process parameters of microwave power, temperature and catalyst weight content. Under the conditions of 1200 W, 600 °C and 10 wt% of catalyst to feedstock, an optimal bio-oil yield of 54.3 wt% was achieved over the MoS2 catalysts. Notably, compared with commercial MoS2-catalyzed and non-catalyzed MAP, the self-made MoS2-catalyzed process realized the improvement for the content of both general phenol species and specific alkoxyphenols component, reaching up to 90.1 % and 77.3 %, respectively at 1200 W, 600 °C and 10 wt% of catalyst to feedstock, which was superior to most of the previously reported candidates. The contrast experiment evidenced the bifunctional roles of MoS2 as both microwave absorbent and catalyst. It could not only promote the production of bio-oil but also inhibit the carbonization, selectively upgrade non-condensable gas to bio-oil, and simultaneously limit the second pyrolysis of alkoxyphenols, which jointly leads to the efficient synthesis of alkoxyphenols-rich bio-oil. This work provides guidance for producing phenols-rich bio-oil and other highly value-added products through the microwave-assisted catalytic pyrolysis of biomass over transition metal dichalcogenides materials.