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The large-scale blooming of Enteromorpha prolifera (EP) results in "green tide," triggering significant environmental issues. However, EP as algal biomass can be converted to syngas through fast pyrolysis. This research investigates the fast pyrolysis of modeled compounds of EP for syngas production. Rhamnose (Rha), glucuronic acid (GlcA), aspartic acid (Asp), glutamic acid (Glu), and alanine (Ala) are used as the model compounds. This study employs experiments and simulations on fast pyrolysis processes. The results reveal that polysaccharide sulfate (PS) undergoes various reactions, including glycosidic bond cleavage, pyran ring opening, dehydration, and C-C bond cleavage. Simultaneously, amino acids experience dehydration, deamination, decarboxylation, and decarboxylation reactions. Fast co-pyrolysis of modeled compounds of EP, the monosaccharides and uronic acid molecules produced by PS pyrolysis also attack each other with amino acid molecules to produce other substances. The pyrolysis gas obtained from the model compounds of PS exhibits the highest CO content. Notably, amino acids possess a superior capability to produce H 2 compared with PS. With the fast co-pyrolysis of EP model compounds, the CO 2 content increases while the CO content decreases. This study provides a theoretical basis for the fast pyrolysis of EP to produce syngas. [Display omitted] • Fast pyrolysis reaction processes of modeled substances of EP are conducted. • The synergistic effect between modeled substances is researched. • The H 2 and CO contents from fast pyrolysis of EP are 18.08 vol% and 25.69 vol%. [ABSTRACT FROM AUTHOR]

Aqueous phase hydrodeoxygenation of lignin pyrolysis oil and related model compounds were investigated using four noble metals supported on activated carbon. The hydrodeoxygenation of guaiacol has three major reaction pathways and the demethylation reaction, mainly catalyzed by Pd, Pt and Rh, produces catechol as the products. The presence of catechol and guaiacol in the reaction is responsible for the coke formation and the catalysts deactivation. As expected, there was a significant decrease in the specific surface area of Pd, Pt and Rh catalysts during the catalytic reaction because of the coke deposition. In contrast, no catechol was produced from guaiacol when Ru was used so a completely hydrogenation was accomplished. The lignin pyrolysis oil upgrading with Pt and Ru catalysts further validated the reaction mechanism deduced from model compounds. Fully hydrogenated bio-oil was produced with Ru catalyst. [ABSTRACT FROM AUTHOR]

Highlights: [•] Pyrolysis of SW kraft lignin and pine wood were examined. [•] Various NMR and GPC were used to characterize various pyrolysis oils. [•] Fast pyrolysis improved cleavage of methoxyl, aliphatic C C and carbonyl bonds. [•] Fast pyrolysis produced more PAH from lignin. [•] Molecular weight of fast pyrolysis oils increased by ∼100%. [Copyright &y& Elsevier]

Abstract: The hydrogenation of biomass pyrolysis oils to upgraded biofuels, especially the aliphatic compounds with a low boiling range has attracted significant research attention. However, compared with the water soluble phase of pyrolysis oils, the water insoluble parts are relatively difficult to upgrade due to the complex high molecular weight aromatic structures. To solve this problem, a two step hydrogenation of water insoluble pyrolysis oil (heavy oil) produced from pyrolysis of pine wood ethanol organosolv lignin (EOL) at 600°C for 30min was examined. Ru/C was used as the catalyst and water was used as the dispersant for the heavy oil and hydrogenation products. The carbon conversion yields for the first and second step hydrogenation are 35% and 33% (overall molar% of carbon content in the heavy oil), respectively. The products of first step of hydrogenation are primarily aromatic molecules which are produced from the hydrolytic cleavage of ether bond and methoxy groups in the heavy oils. Further hydrogenation was shown to covert the insoluble heavy oils (weight average molecular weight is 265g/mol) to the aliphatic alcohols and other aliphatic components which could be used as renewable gasoline. As far as we know, this is the first reported effort to upgrade water insoluble parts of lignin pyrolysis oil to the total aliphatic components by aqueous phase hydrogenation. [Copyright &y& Elsevier]

Conventional methods faced challenges in pretreating natural cellulose fibres due to their high energy consumption and large wastewater drainage. This research devised an efficient solid-state pretreatment method for pretreating hemp fibres using ethanolamine (ETA) assisted by microwave (MW) heating. This method produced a notable removal rate of lignin (85.4 %) with the highest cellulose content (83.0 %) at a high solid content (30 %) and low temperature (70 °C). Both FT-IR and XRD analyses indicated that the pretreatment did not alter the structure of cellulose within the hemp fibres but increased crystallinity as the CrI increased from 84 % in raw hemp fibre to 89 % in pretreated fibre. As a result, it produced hemp fibres with impressive fineness (4.6 dtex) and breaking strength (3.81 cN/dtex), meeting the requirement of textile fibre. In addition, an improvement in glucose concentration (15.6 %) was observed in enzymatic hydrolysis of the MW pretreated hemp fibres compared to the fibres pretreated without MW. Furthermore, the FT-IR and NMR data confirmed that the amination of lignin occurred even at low temperature, which contributed to the high lignin removal rate. Thus, this study presents a potentially effective energy-saving, and environmentally sustainable solid-state method for pretreating hemp fibres. [Display omitted] [ABSTRACT FROM AUTHOR]

Hemp represents a valuable resource of natural fibers on account of its environment favorable characteristics and excellent fiber quality. To fabricate hemp fibers, the traditional alkaline boiling degumming is used in the industry, which consumes a lot of water and generates a substantial amount of wastewater. In the present study, a novel eco–friendly solid–state degumming method was developed by using ethanolamine (ETA). The ETA degumming exhibited a high lignin removal rate (87.5%) at a high solid loading (30%), decreasing water consumption by 33.3%. Moreover, the ETA solution was readily reused up to five times without purification. The degummed hemp fibers possessed commendable fitness (4.2 dtex) and breaking strength (3.75 cN/dtex) without change of the crystalline cellulose structure. Besides, the lignin in wastewater was confirmed to be aminated, which is beneficial to the potential valorization of the by–product. Thus, the solid–state ETA degumming method holds significant potential for the fabrication of hemp fibers. [Display omitted] • A novel eco-friendly solid–state degumming method by using ethanolamine. • A high lignin removal rate (87.5%) at a high solid loading (30%). • Ethanolamine solution was reused up to five times without purification. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Coal Tar Pitch oxidation is simulation by ReaxFF MD. • Effect of temperature and oxygen content on CTP reaction mechanism is detailed analyzed. • Evolution of both generation and cleavage of all types of molecular bonds is explored. • Overall product distribution is tracked and glyoxal is observed to be the major organic gas product. • Major reaction pathways for CTP oxidation are obtained. Abstract Molecular dynamic (MD) simulations based on the reactive force field (ReaxFF) were successfully used for the study of coal tar pitch (CTP) oxidation process under medium temperature. Three CTP components were divided into three fractions: pitch acetone solubles (PAS), pitch pyridine soluble-acetone insolubles (PPS), and pitch pyridine insolubles (PPI). A series of ReaxFF MD simulations were conducted to study the influence of temperature and oxygen content on CTP oxidation mechanism. The results demonstrate that the oxidation process is initiated by generation of C O bonds and O O bonds following intramolecular hydrogen transfer. The phenoxyl free radical which is initially formed by the cleavage of hydroxyl and the oxidization of benzene ring is an important intermediate product, it plays a key role in the formulation of H 2 O, CO 2 and glyoxal, and it also promotes the combination of two small molecules. The cleavage of C H bonds is more likely to happen when temperature is larger than 650 K. The PPI fraction is more stable compared with PAS and PPS components. The major reaction pathways are analyzed, and it's observed that the reaction pathways are able to reproduce and explain the experimental findings in the CTP oxidation process. [ABSTRACT FROM AUTHOR]

The large-scale flooding of Enteromorpha prolifera (EP) forms "green tide", which causes severe environmental problems. However, EP, an algal biomass, can be converted into syngas via pyrolysis. In this study, the pyrolysis mechanisms of the main compositional models of EP used to produce syngas are investigated using a combination of molecular dynamics simulations and fixed-bed experiments. Rhamnose (Rha), glucuronic acid (GlcA), aspartic acid (Asp), glutamic acid (Glu), and alanine (Ala) are used as the model compounds. The results indicate that H 2 is primarily produced by Glu (reached 24.68 vol%), followed by Asp and Ala, and CO is produced by Ala (reached 44.94 vol%), Glu, and Asp. The molecular dynamics simulation results indicate that the energy barriers for the pyrolysis of Glu and Ala to produce H 2 and CO, respectively, are the lowest. Three amino acids undergo dehydration, deamination, and decarboxylation. Moreover, the synergistic effect of the three amino acids in co-pyrolysis is reflected in the production of hydrogen groups from Asp; and the hydrogen group then attacks Glu to seize the hydrogen group on it to produce hydrogen. In addition, the H 2 content in the syngas produced by the separate pyrolysis of Rha (17.75 vol%) and GlcA (17.35 vol%) are similar and lower than those of the Rha and GlcA mixtures (19.12 vol%). The CO content in the pyrolysis gas of GlcA is higher than that of Rha. The simulation results prove that the amino acids undergo dicarboxylic and deamination reactions to produce amino acids and CO 2. Meanwhile, polysaccharide sulfate breaks glycosidic bonds, producing free radicals such as hydrogen and hydroxyl groups at 700 K. When the temperature rises to 1900 K, the products of the previous stage further break the bond, producing small-molecule gases. However, the addition of polysaccharide model compounds promotes the production of CO 2 and C O groups and inhibits the formation of CO. Co-pyrolysis cannot increase H 2 , and the synergistic effect is not significant. Moreover, Ni and SAPO-34 exhibited good catalytic activities, which could increase syngas production. A raw materials to catalyst ratio of 5:1 is a good choice because it improves the H 2 and CO contents and makes economical use of Ni. With the increase of Ni catalyst cycles, H 2 content also shows a decreasing trend, from 22.86 vol% to 16.27 vol% (third cycle). With the number of SAPO-34 cycles, the increase of CO content, from 28.66 vol% to 32.67 vol% is explained by the increase in the specific surface area of the catalyst caused by repeated use, which increases the selectivity of C2 and enhances the ability of decarbonylation. This study focuses on the syngas reaction paths and pyrolysis reactions of different EP model compounds. The pyrolysis mechanism of EP to produce syngas is determined using a combination of experiments and simulations, providing a method for the energy utilization of EP. [Display omitted] • The reaction pathways of syngas from model compounds of EP is clarified. • The synergistic effects of amino acids or saccharides exist in the hydrogen production. • The most likely amino acids to produce H2 and CO are glutamic acid and alanine. • The proportion of hydrogen gas produced by rhamnose glucuronic acid is similar. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A tandem bubbling fluidized bed/fixed bed reactor was used for CFP of bamboo sawdust. • Effect of pyrolytic/catalyst temperature on bio-oil yield and distributions was studied. • Ex-situ enhanced the formation of alkylphenols using base metal oxides as catalysts. • Mixed CaO with HZSM-5 mode facilitated the content of aromatic hydrocarbons in bio-oil. • Synergistic effect between base catalysts and HZSM-5 was revealed. Abstract Catalytic fast pyrolysis of bamboo sawdust was conducted by a tandem bubbling fluidized bed/fixed bed reactor. Effect of pyrolysis and catalyst temperatures on product yield was studied. In addition, synergistic effect of HZSM-5 and base catalysts (including CaO, MgO, and SrO) for the promotion of aromatic hydrocarbons was revealed. Experimental results illustrated that both pyrolytic and catalytic reactor temperatures played pivotal roles in the yield of bio-oil, and the optimal pyrolysis and catalytic reactor temperatures were 550 °C and 500 °C, respectively. Ex-situ catalytic trial decreased the yield of bio-oil compared to in-situ run, while it facilitated the formation of phenol and alkylphenols. Mixed catalytic upgrading modes exhibited more significant aromatization and deoxygenation activities than sequential ones. In particular, ex-situ run using CaO mixed with HZSM-5 increased the concentration of aromatic hydrocarbons to 31.34%, which was ∼11.48% higher than that derived from CaO and HZSM-5 sequentially processed mode. The dominated products in alkylphenols were cresol isomers and ethylphenols, and compared to sequential cases, mixed catalytic upgrading trials promoted the relative selectivity of phenol. Synergistic effect of base catalysts and HZSM-5 contributed to the production of monocyclic aromatic hydrocarbons, and CaO mixed with HZSM-5 mode showed the most prominent synergistic effect for the enhanced relative selectivity to xylenes and toluene. [ABSTRACT FROM AUTHOR]

Ramie provides the longest and strongest natural fiber in textile industry, but its traditional degumming process is costly and requires a large amount of alkali, which causes serious environmental concerns. In the current work, a steam explosion (STEX) treatment followed by sodium percarbonate (SP) soak degumming process was investigated. Microstructure, chemical composition and mechanical properties of the refined ramie fibers were comprehensively characterized. The residual gum content was below 5%, the fineness was higher than 1600 Nm (6.25 dtex), the breaking tenacity was 5.4 cN/dex, and the whiteness was above 50%. All of the properties met the requirements of Chinese national standard, and the breaking tenacity and whiteness were notably better than those of the fibers degummed traditionally. In addition, environmental impacts of the new degumming process were evaluated. Only 50% chemicals were needed for the new process, and chemical oxygen demand (COD) of the waste reduced to 35% of the traditional method. Therefore, the new method was more environment-friendly and economically feasible. It has great potential for industry applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • The highest relative content of H 2 from MACP of waste tires over 10 wt. %Ni/HZSM-5. • The optimal reaction pathways of catalytic pyrolysis of NR, SBR, and BR for hydrogen are found. • The simulation of Ni/HZSM-5 shows the best hydrogen production capacity consistent. The mechanism for the formation of gaseous products, especially hydrogen, from the catalytic pyrolysis of waste tires by using Ni-based catalysts has been studied. The catalytic pyrolysis of the three essential components of waste tires such as natural rubber (NR), styrene-butadiene rubber (SBR), and cis -polybutadiene rubber (BR) was simulated and the pyrolysis fracture of the molecular chain was investigated. This work aims to provide a deeper understanding of the reaction thermodynamics and kinetics for the formation mechanisms of gaseous products, primarily hydrogen. Microwave-assisted catalytic pyrolysis of the waste tires over Ni-based catalysts was carried out and used to assent to the simulation results. The study revealed that with the incorporation of 10 wt% Ni/ZSM-5 catalyst, the relative content of H 2 from the catalytic pyrolysis of waste tires can be significantly improved by about 41.3 % in comparison to the same measurement done in the absence of the catalyst. Kinetic and thermodynamic simulations for the catalytic pyrolysis of waste tires were also performed and the corresponding energy barriers and Gibbs free energy changes were calculated. Accordingly, the optimal reaction path for the hydrogen production was determined by comparing and analyzing the values of those parameters. It was confirmed that the addition of Ni, ZSM-5, and Ni/ZSM-5 catalysts promote the hydrogen production reaction pathways. Among those catalysts, the simulation result verified that Ni/ZSM-5 brings a pronounced hydrogen production capacity, which was consistent with the experimental findings. [ABSTRACT FROM AUTHOR]

[Display omitted] • A high total diols selectivity of 83.9% was obtained, in which EG selectivity was 58.9%. • The NiCu-WO x-1 -O(H) interfaces facilitated the transformation of glucose into glycolaldehyde. • The appropriate amount of NiCu alloy and WO 3 ensured an excellent synergistic effect for C C cleavage and hydrogenation. • The structure of WO 3 -wrapped metals enabled the reaction to proceed in a well-defined sequence. One-pot catalytic conversion of cellulose to ethylene glycol (EG) provides an efficient way toward the production of high value-added chemicals from the abundant biomass resource. However, control of product selectivity is a challenge due to the thermal instabilities of cellulose derived sugars. Here, a series of multifunctional NiCu/WO 3 catalysts were prepared and applied to this process. By tuning the metal ratio and WO 3 content, a high EG selectivity of 58.9% was obtained. The selectivity of total diols even reached 83.9%. Besides, the catalyst revealed excellent performance in the conversion of raw biomass. Characterization results showed that the special catalyst structure of WO 3 -wrapped metal particles enabled the reaction to proceed in a well-defined sequence and also facilitated the formation of NiCu-WO x-1 -O(H) interfacial sites. These interfacial sites offered high activity for the C C bond cleavage to produce glycolaldehyde from glucose. An appropriate amount of each active site ensured a well-synergistic effect of C C cleavage and hydrogenation capabilities, thus resulting in the highly selective formation of EG. [ABSTRACT FROM AUTHOR]

Pyrolysis is a promising method for converting biomass to biofuels. However, some of pyrolysis oil's physiochemical properties still limit its commercial applications. In this study, the autohydrolysis pretreatment at 175 ± 3 °C for 40 min was conducted to improve the resulting pine pyrolysis oil’s properties as a fuel. During autohydrolysis, deacetylation and decomposition of hemicellulose was observed by ion-exchange chromatography and Fourier transform infrared spectroscopy (FT-IR). In addition, the cleavage of lignin ether bonds was clearly determined by 13 C cross-polarization/magic angle spinning (CP/MAS) nuclear magnetic resonance (NMR). Phosphitylation followed by 31 P NMR analysis of the heavy oils gave detailed structural information of the hydroxyl groups; the results revealed that autohydrolysis pretreatment led to a reduction of carboxyl acids in the heavy oils generated at all three pyrolysis temperatures (400, 500, and 600 °C). The 31 P NMR analysis also revealed that autohydrolysis pretreatment led to a reduction of condensed phenolic hydroxyl groups in the heavy oils produced at 600 °C. 1 H- 13 C heteronuclear single-quantum correlation (HSQC) NMR analysis showed that at a pyrolysis temperature of 600 °C, the pretreated pine produced lower methoxy group constituents. Both 31 P and HSQC NMR results indicated that autohydrolysis pretreatment increased levoglucosan yields in the bio-oils. [ABSTRACT FROM AUTHOR]

Ni/ZSM-5 catalyst has better catalytic effects leading to higher H 2 and hydrocarbon productions contents. [Display omitted] • The mechanism of hydrogen from CP of WTR was studied by simulations and experiments. • The Ni/ZSM-5 catalyst improves the hydrogen yield from CP of WTR. • Three catalysts reduce the energy barriers to generating the H2 pathway. • The catalysts reduce the pyrolysis temperature and improve the gas production rate. • The experimental results show that Ni/ZSM-5 has the best hydrogen production effect. Waste tires are currently disposed of through various approaches such as landfill and incineration, which not only causes environmental pollution, but also lead to the wastage of resources. As an important type of solid waste, tire rubber has a high carbon-to-hydrogen ratio, which makes it a good material for hydrogen production from pyrolysis. In this study, molecular dynamics simulations combined with experimental methods are used to explore the mechanism of hydrogen production from the catalytic pyrolysis (CP) of waste tire rubber (WTR) over Ni, ZSM-5 and Ni/ZSM-5. The simulation results show that the three catalysts potentially promote the release of hydrogen radicals from monomers and facilitate attack by H· radicals to generate hydrogen. Compared with ZSM-5 and Ni, the Ni/ZSM-5 catalyst exerts better catalytic effects, leading to higher contents of produced H 2 and hydrocarbons. In the low-temperature stage, the long chain cracks into monomer compounds, which mainly include isoprene, styrene, and 1,3-butadiene. Meanwhile, in the high-temperature stage, free radicals attack monomers to generate small molecules. The main gas products from the catalytic pyrolysis of waste tire rubber are hydrogen, methane, and ethylene. The use of all three catalysts leads to a low final catalytic pyrolysis temperature, high catalytic pyrolysis rate, and excellent catalytic effect. This work aims to provide a deeper understanding of the reaction thermodynamics and kinetics for the formation mechanisms of gaseous products, primarily hydrogen. [ABSTRACT FROM AUTHOR]

• The CHP of lignocellulosic biomass was carried out over a hierarchical catalyst. • The products of CFP and CHP of rice husk are compared. • CHP of rice husk (RH) over hierarchical catalyst led to a high hydrocarbons content. • The optimum conditions for the CHP of RH were 400 °C and 35 bar. In this study, we compare the products of catalytic fast pyrolysis (CFP) and catalytic hydropyrolysis (CHP) of rice husk over an HZSM-5-based hierarchical catalyst. The results suggest that the addition of hydrogen inhibits polycondensation reactions, leading to a reduction of 2.3 wt% in coke yield at 400 °C and 35 bar. The presence of hydrogen increases the relative content of hydrocarbons in both liquid and gas products, with a more significant increase in CH 4 and C 2 –C 3 yield in the gas, suggesting that hydrodeoxygenation, decarbonylation, and decarboxylation reactions are promoted. Alkali-treatment of the HZSM-5 improves the catalytic activity and coking resistance of the catalyst. The addition of an extra external MCM-41 layer to the alkali-treated HZSM-5 further improves the catalytic activity, resulting in a relative hydrocarbon content of 48.9%, which is higher than that obtained with the alkali-treated HZSM-5 and pristine HZSM-5. We also report the effect of pressure on the products. As the pressure increases from 1 to 35 bar, the relative content of hydrocarbons increases from 39.9 to 48.9%, while the coke yield decreases from 3.4 to 1.9 wt%, and CH 4 and C 2 –C 3 yields decrease from 10.3 wt% and 5.1 wt% to 14.2 wt% and 6.7 wt%, respectively. As the temperature increases from 300 to 400 °C, the relative content of hydrocarbons increases from 38.2% to 48.9%. Both CH 4 and C 2 –C 3 yields reach the highest values of 14.2 wt% and 6.7 wt% at 400 °C and 35 bar. [ABSTRACT FROM AUTHOR]

• A method for splitting kenaf using microwave combined with lactic acid was proposed. • Fibers have excellent dispersion and suffer minor damage. • The extracted lignin is less damaged and keeps its structural integrity. • Potential for biomass clean production due to low chemicals and time consumption. According to diverse application purposes, different scales of lignocellulosic fibers were obtained from biomass through various preparation conditions. However, the pollution in the fiber separation process restricted the development of the related industry. This research proposed clean fiber separation technology of kenaf bast that combined microwave and lactic acid treatment. The traditional sulfate method was also carried out for comparison. The raw kenaf bast and produced fibers were characterized with wet chemistry analyses, SEM, FTIR, GPC and NMR. The results showed that compared with the traditional method (lignin removal rate 88.3 %, cellulose Mw = 607 kg/mol), the new method had higher lignin removal capacity (94.68 %) and less damage to cellulose (Mw = 1174 kg/mol). TG and NMR analysis showed that the separated crude lignin had a high pyrolysis temperature (350℃), minor structural changes and better uniformity, which was close to natural lignin. In addition, it was calculated that the processing time of the new method was reduced by 82.3 %, which reduced energy loss and waste liquid pollution. This study proved that microwave-assisted lactic acid treatment could separate kenaf fibers efficiently with less damage and pollution. [ABSTRACT FROM AUTHOR]

• Kapok fiber with thin cell wall and large lumen was used as supporting material for PCM. • The composite made by kapok and hollow PET fibers encapsulated PCM by vacuum impregnation. • This composite demonstrated obvious thermal regulating capacity in the cooling/hot environment. • The composite demonstrated robust leakage resistance to laundry, pressure and heat/cooling cycling. • This composite has great potential for dynamic heat insulation and thermal regulation. Kapok fiber, an agricultural product, is a typical cellulosic fiber with the features of thin cell wall and large lumen. Herein, a microtubule-based composite with high porosity of 98.03 % was prepared using kapok fibers and hollow PET. The kapok fiber-based composite successfully encapsulated a phase change material (PCM), that is a fatty acid ester of myristic acid and tetradecyl alcohol (MA-TD), in the microtubules by vacuum impregnation. The SEM showed that the PCM was encapsulated in the lumens of the fibers with a calculated percentage of 40.5 %. This condition provided the composite a basic thermal insulation from air pockets in the composite and a dynamic thermal insulation from the PCM. The kapok/PET/MA-TD could absorb 76.8 J/g latent heat in the comfort temperature range of 24 °C – 42.3 °C or release 77.4 J/g latent heat in the comfort temperature range of 29.7 °C – 10.5 °C. It withstood repeated laundry and exhibited robust leakage resistance to continuous heating/cooling under pressure. In addition, the composite was successfully used to dynamically regulate the temperature with obvious thermal regulating capacity in the simulated cooling/hot environments. Such material will be a robust candidate for dynamic heat regulating and thermal insulating applications. [ABSTRACT FROM AUTHOR]

• With the microwave-assisted ultrasonic treatment, the degumming process was more eco-friendly and efficient. • All properties were better than those of the fibers from traditionally degumming process. • The new method helped improve the technology for rapid and clean preparation of new biomass fibers. Apocynum venetum (AV) is a promising textile resource but lacks efficient degumming method. This study proposed a novel degumming process which coupled microwave pretreatment with ultrasonic degumming on AV bast. The traditional chemical degumming was also carried out for comparison. The raw AV bast and produced fibers were characterized with wet chemistry analyses, SEM, FTIR and GPC. Compared with traditionally degummed product, the AV fibers prepared by microwave-assisted ultrasonic degumming showed a better breaking tenacity (7.67 cN/dtex, comparing to 6.90 cN/dtex with the traditional method) and superior average length (32.5 mm, comparing to 23.0 mm). Moreover, compared with the traditional degumming method, the processing time of the new method was reduced to 31.2 %, and the chemical usage was reduced to 44.8 %. The new degumming method could efficiently produce higher quality AV fibers with less pollution. [ABSTRACT FROM AUTHOR]