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In this work, waste corncob with high hemicellulose content was selected as the carbon source to investigate the effect of hemicellulose extraction on the prepared sulfonated biochar for biodiesel production. After hemicellulose extraction, the optimized sulfonated biochar with a maximum -SO 3 H density of 2.05 mmol/g was synthesized under 3 h of carbonization at 300 °C, then 2 h of sulfonation at 90 °C. For the esterification, the 98.5% oleic acid equilibrium conversion was achieved under optimized reaction parameters: a 12:1 molar ratio (methanol/oleic acid) and a 10 wt% catalyst dosage at 65 °C for 4 h. The catalyst still reached 70% conversion efficiency after 10 cycles, which proved that the hemicellulose extraction not only played a role in the rational utilization of biomass but also the significantly-improved catalyst lifetime was beneficial to the sustainable production of biodiesel. [Display omitted] • Hemicellulose Extraction enables multi-stage utilization of biomass. • Hemicellulose extraction as a pretreatment for the SCB-SO 3 H catalyst. • The optimized SCB-SO 3 H catalyst has a sulfonic acid density of 2.05 mmol/g. • The 98.5 % oleic acid conversion was obtained at optimal conditions. • The SCB-SO 3 H catalyst can be recycled 10 times with > 70 % conversion efficiency. [ABSTRACT FROM AUTHOR]

Abstract: Sweet sorghum is a high-yielding energy crop that leaves a large amount of lignocellulosic residues after the sugar fraction fermented to ethanol. Here, we developed a biphasic kinetic model for the dilute sulfuric acid-catalyzed hemicellulose hydrolysis of sweet sorghum bagasse at temperatures of 110–150°C, and we then calculated the kinetic parameters for xylose production and furfural decomposition. The results indicated that elevated reaction temperatures promote the hydrolysis of hemicellulose and the degradation of xylose. The xylose yield increased in proportion to reaction time in the initial stages and then declined due to the degradation of xylose to furfural. The pre-exponential factors for the ‘easy-to-hydrolyze’ fraction, the ‘hard-to-hydrolyze’ fraction of hemicellulose and xylose degradation were 3.53×106, 1.80×105 and 0.62min−1, respectively, and the activation energies were 60.7, 58.1 and 14.5kJ/mol, respectively. The ideal hydrolysis condition for xylose production was 140°C for 50min, under which the xylose yield reached 60% of hemicellulose weight. This xylose can be used to form bioethanol and produce further downstream products. [Copyright &y& Elsevier]

In this work, the role of Brønsted acid for furfural production in biomass pyrolysis on supported sulfates catalysts was investigated. The introduction of Brønsted acid was shown to improve the degradation of polysaccharides to intermediates for furfural, which did not work well when only Lewis acids were used in the process. Experimental results showed that CuSO 4 /HZSM-5 catalyst exhibited the best performance for furfural (28% yield), which was much higher than individual HZSM-5 (5%) and CuSO 4 (6%). The optimum reaction conditions called for the mass ratio of CuSO 4 /HZSM-5 to be 0.4 and the catalyst/biomass mass ratio to be 0.5. The recycled catalyst exhibited low productivity (9%). Analysis of the catalysts by Py-IR revealed that the CuSO 4 /HZSM-5 owned a stronger Brønsted acid intensity than HZSM-5 or the recycled CuSO 4 /HZSM-5. Therefore, the existence of Brønsted acid is necessary to achieve a more productive degradation of biomass for furfural. [ABSTRACT FROM AUTHOR]

Desulfurization is important to the enhancement of biodiesel quality. In this study, the effects of reactant and catalyst addition and operations conducted on sulfur content at each stage during the biodiesel preparation process were examined. Based on the results of sulfide qualification and quantification, a high vacuum distillation method was developed to remove the sulfides in crude biodiesel. Biodiesel was separated into different fractions based on the boiling point and the sulfur content of each fraction was determined. Experimental results showed that most sulfides were distilled out with light and heavy fractions. Intermediate fraction was separated from the other fractions, resulting in high quality biodiesel with low sulfur content. The total yield of distillation fractions with sulfur content lower than 10 ppm reached 84.1%. A set of distillation facility with capacity of 10 m3/h was designed and developed accordingly for large-scale tests. The yield of low-sulfur biodiesel was around 83%, close to that obtained in the laboratory studies. In addition, economic analysis showed that the distillation facility can make revenue of more than $1.8 million per year, indicating that high vacuum distillation is economically feasible and promising for biodiesel desulfurization, especially in industrial application. Image 104946 • A high vacuum distillation method was proposed to remove sulfides in crude biodiesel. • Sulfides in crude biodiesel were qualitatively and quantitatively analyzed. • The total yield of biodiesel with sulfur content lower than 10 ppm was 84.1%. • Distillation facility with capacity of 10 m3/h was developed for large-scale tests. • The process is economically feasible for low-sulfur biodiesel production. [ABSTRACT FROM AUTHOR]

In industry, mass transfer limitation is a major and widespread problem in most of vegetable oil epoxidation reactors. To improve the quality of products and the efficiency of production, it is essential to understand the law of mass transfer in the epoxidation reaction system. In present work, epoxidation of fatty acid methyl esters with performic acid generated in situ was studied in a stirred vessel at 50–80 °C. At first, the Sauter mean diameter (D 32 ) was determined and correlated, the correlation can predict the D 32 evolution of the reaction. Then, individual experiments were performed to separately determine the intrinsic kinetic parameters and the mass transfer parameters. Finally, a macroscopic kinetic model was developed, which can well describe the effect of droplet size on the reaction. Noteworthy, the mass transfer limitation was significantly increased when reaction temperature rises to 80 °C. [ABSTRACT FROM AUTHOR]

Ammonia (NH 3 ) is a potential hydrogen carrier as alternative fuel and feedstock for hydrogen production. In this study, plasma synthesis of NH 3 was conducted in a packed-bed dielectric barrier discharge (DBD) reactor using Al 2 O 3 as the catalyst. In order to explore the mechanism of hydrogenation of plasma-excited nitrogen for NH 3 synthesis, the whole NH 3 synthesis process was divided into three steps including N 2 activation, hydrogenation of plasma-excited N(a), and desorption of NH 3 (a) from catalyst. The effects of reaction conditions on the three steps and corresponding NH 3 production were examined. Results showed that more plasma-excited nitrogen species were formed through N 2 activation at higher N 2 flow rate, discharge time and discharge power for N 2 activation. Hydrogenation of plasma-excited N(a) to form NH 3 (a) was improved by more discharge time at the second step. Higher discharge temperature for N(a) hydrogenation favored NH 3 (a) desorption from catalyst and increased NH 3 production at the second step, with the total NH 3 yield slightly changed. In addition, one-step NH 3 synthesis in plasma was investigated and compared with the three-step process. The results will provide reference for catalyst and reactor design in plasma synthesis of ammonia. [ABSTRACT FROM AUTHOR]

Most of the plasticizers used during poly (vinyl chloride) processing are typically toxic petroleum-based phthalates. Furthermore, large amount of edible oils become waste all over the world, fortunately, waste cooking oils have the potential to be an economic alternative for synthesizing different biomaterials. This study aimed to synthesis an improved properties and cost competitiveness cleaner bio-plasticizer using waste cooking oil methyl esters as staring raw materials. In this paper, waste cooking oil methyl esters were structurally modified i.e., transesterification and epoxidation reaction, to prepare epoxide waste cooking oil 2-ethylhexyl esters. The in-situ epoxidation was mainly studied by response surface methodology, with optimum conditions: reaction time was 7 h, molar ratio of C C bonds/FA/H 2 O 2 was 1.00/0.35/2.41, and reaction temperature was 65.84 °C with a maximum relative percentage conversion to oxirane of 92%. Also, the plasticizing effectiveness of epoxide waste cooking oil 2-ethylhexyl esters to substitute toxic plasticizer dioctyl phthalate were studied. Results showed that the mechanical and thermal performance of PVC samples was significantly improved with partial substitutions, while the migration resistance was slightly decreased. Comparison with conventional epoxy compound highlighted that epoxide waste cooking oil 2-ethylhexyl esters had superior low temperature property, oxidation stability, and remarkably reduced the glass transition temperature of PVC. In conclusion, the prepared epoxide via structural modification from waste cooking oil methyl esters proved to be an effective alternative to dioctyl phthalate, replacing about 40% of the total plasticizer. This may lead to the eco-development of waste cooking oil materials, and makes the plasticizing process more environmentally friendly. [ABSTRACT FROM AUTHOR]

In this work, amphoteric ion-exchange membranes (AIEMs) prepared from fluoro-methyl sulfonated poly(arylene ether ketone- co -benzimidazole)s have been systematically evaluated for their potential usage in all vanadium redox battery (VRB). Our investigation has demonstrated that the compacted structure originated from the self-assembly ionic cross-linking and the positive charged benzimidazole moiety in AIEM matrix could synergistically reduce the vanadium species cross-contamination. The self-discharge time of a single cell assembled with AIEM of optimized chemical structure is over 3 times longer than that with Nafion117, and a desirable conductivity/permeability trade-off can be achieved by tuning the content of benzimidazole moiety. Single cell assembled with the optimized AIEM exhibit higher battery efficiencies and lower capacity loss than that with Nafion117 at current densities of 30, 50 or 70 mA cm −2 . Furthermore, the AIEMs are able to tolerate the strong oxidizing VO 2 + and remain intact for over 370 days, as revealed from ex -situ chemical stability tests. These findings strongly suggest that the as-prepared AIEM can be a good candidate for low-cost and high-performance separator in VRB application. [ABSTRACT FROM AUTHOR]

Undecylenic acid methyl ester (UAME) was continuously produced from methyl ricinoleate using a microwave-assisted pyrolysis system with atomization feeding. The UAME yield of 77 wt.% was obtained at 500 °C using SiC as the microwave absorbent and heating medium. The methyl ricinoleate conversion and UAME yield from microwave-assisted pyrolysis process were higher than those from conventional pyrolysis. The effect of temperature on the pyrolysis process was also investigated. The methyl ricinoleate conversion increased but the cracking liquid yield decreased when the temperature increased from 460 °C to 560 °C. The maximum UAME yield was obtained at the temperature of 500 °C. [ABSTRACT FROM AUTHOR]

Abstract: Lignocellulose and other carbohydrates are being studied extensively as potential renewable carbon sources for liquid biofuels and other valuable chemicals. In the present study, a simple, sensitive, selective, and reliable HPLC method using a photodiode array (PDA) detector and an evaporative light scattering detector (ELSD) was developed for the simultaneous determination of important sugars (d(+)-cellobiose, glucose, xylose, and arabinose), furfural and 5-hydroxymethylfurfural (5-HMF) in lignocellulose hydrolysate. The analysis was carried out on an Aminex HPX-87H column (250mm×4.6mm, 5μm particle size). Ultra-pure water with 0.00035M H2SO4 was used as the mobile phase with a flow rate of 0.6mL/min. The temperature of the ELSD drift tube was kept at 50°C, the carrier gas pressure was 350kPa, and the gain was set at 7. Furfural and 5-HMF were quantified on a PDA detector at 275nm and 284nm, respectively. The sugar concentrations were determined by ELSD. This method was validated for accuracy and precision. The regression equation revealed a good linear relationship (r 2 =0.9986±0.0012) within the test ranges. The method showed good reproducibility for the quantification of six analytes in corncob hydrolysate, with intra- and inter-day variations less than 1.12%. This method is also convenient because it allows the rapid analysis of the primary products of biomass hydrolysis and carbohydrate degradation. [Copyright &y& Elsevier]

• Sargassum horneri is utilized as catalyst for esterification reactions. • The successful grafting of –SO 3 H groups is confirmed by FT-IR and XPS. • The oleic acid conversion of >96% was obtained at optimal conditions. • The catalyst shows remarkable regenerability. A solid acid catalyst prepared by sulfonated Sargassum horneri carbon was utilized for the esterification reaction of oleic acid and methanol. The formed amorphous carbon layers during carbonization and the access of sulfonic acid groups during sulfonation can catalyze the esterification reaction for biodiesel preparation efficiently. The catalyst was characterized by various methods to investigate its physical and chemical properties. With carbonization at 300 °C for 2 h followed by sulfonation at 90 °C for 5 h, the catalyst reached acid density of 1.40 mmol/g. The catalyst dosage, methanol/oleic acid (molar ratio), reaction temperature, and reaction time were optimized to 10 wt%, 15:1, 70 °C, and 3 h, respectively. Under the optimal condition, the conversion of oleic acid reached 96.4%. Additionally, the catalyst was regenerated after four cycles, with the conversion of oleic acid still reaching 95.4%. [ABSTRACT FROM AUTHOR]