Catalytic Upgrading of Biomass Fast Pyrolysis Vapors with Pd/SBA-15 Catalysts

Evaluation of decontamination efficacy of electrolytically generated hypochlorous acid for vesicating agent: A multimodel Study

BACKGROUND

Sulfur Mustard is a strong vesicant and chemical warfare agent that imposes toxicity to the lungs, eyes, and skin after accidental or intended exposure.

OBJECTIVES

The current study was intended to explore in vitro and in vivo decontamination properties of electrolytically generated HOCl (hypochlorous acid) against CEES (2-chloroethyle ethyle sulphide), a known sulfur mustard simulant & vesicating agent.

METHODS

In vitro studies were carried out using UV spectroscopy and GC-MS methods. In vivo studies were perfomred in Strain A and immune compromised mice by subcutaneous as well as prophylactic topical administrion of HOCl pretreated CEES. The blister formation and mortality were considered as end-point. Histopathological study was conducted on skin samples by H & E method. DNA damage studies measuring γ-H2AX and ATM has been carried out in human blood using flow cytometry. Anti-bacterial action was tested by employing broth micro dilution methods. Comparative study was also carried out with known oxidizing agents.

RESULTS

The topical application of pre-treated CEES at 5, 30 min and 1 h time points showed significant (p<0.001) inhibition of blister formation. DNA damage study showed reduced mean flourences intensity of DSBs nearly 17-20 times, suggesting that HOCl plays a protective role against DNA damage. Histopathology showed no sign of necrosis in the epidermis upto 5 min although moderate changes were observed at 30 min. Pretreated samples were analyzed for detection of reaction products with m/z value of 75.04, 69.08, 83.93, 85.95, 123.99, 126.00, and 108.97. HOCl showed strong bactericidal effect at 40 ppm. The absorbance spectra of HOCl treated CEES showed lowered peaks in comparison to CEES alone and other oxidizing agents Conclusion: In a nutshell, our results signify the decontamination role of HOCl for biological surface application.

Nanocasting synthesis of BiFeO3 nanoparticles with enhanced visible-light photocatalytic activity

In this work, monodisperse BiFeO₃ nanoparticles with a particle diameter of 5.5 nm were synthesized by a nanocasting technique using mesoporous silica SBA-15 as a hard template and pre-fabricated metal carboxylates as metal precursors. To the best of our knowledge, the synthesized particles are the smallest BiFeO₃ particles ever prepared by any method. The samples were characterized by X-ray powder diffraction, transmission electron microscopy and UV-vis diffuse reflectance spectroscopy. The phase purity of the product depends on the type of carboxylic acid used in the synthesis of the metal precursors, the type of solvent in the wet impregnation process, and the calcination procedure. By using tartaric acid in the synthesis of the metal precursors, acidified 2-methoxyethanol in the wet impregnation process and a calcination procedure with intermediate plateaus, monodisperse 5.5 nm BiFeO₃ nanoparticles were successfully obtained. Furthermore, the nanoparticles were applied in photodegradation reactions of rhodamine B in aqueous solution under visible-light irradiation. Notably, the cast BiFeO₃ nanoparticles demonstrated very high efficiencies and stability under visible-light irradiation, much higher than those of BiFeO₃ nanoparticles synthesized by other synthetic methods. The possible mechanism in the photodegradation process has been deeply discussed on the basis of radical trapping experiments.

Scaling-Up of Bio-Oil Upgrading during Biomass Pyrolysis over ZrO2 /ZSM-5-Attapulgite

Ex situ catalytic biomass pyrolysis was investigated at both laboratory and bench scale by using a zeolite ZSM-5-based catalyst for selectively upgrading the bio-oil vapors. The catalyst consisted of nanocrystalline ZSM-5, modified by incorporation of ZrO₂ and agglomerated with attapulgite (ZrO₂ /n-ZSM-5-ATP). Characterization of this material by means of different techniques, including CO₂ and NH₃ temperature-programmed desorption (TPD), NMR spectroscopy, UV/Vis microspectroscopy, and fluorescence microscopy, showed that it possessed the right combination of accessibility and acid-base properties for promoting the conversion of the bulky molecules formed by lignocellulose pyrolysis and their subsequent deoxygenation to upgraded liquid organic fractions (bio-oil). The results obtained at the laboratory scale by varying the catalyst-to-biomass ratio (C/B) indicated that the ZrO₂ /n-ZSM-5-ATP catalyst was more efficient for bio-oil deoxygenation than the parent zeolite n-ZSM-5, producing upgraded bio-oils with better combinations of mass and energy yields with respect to the oxygen content. The excellent performance of the ZrO₂ /n-ZSM-5-ATP system was confirmed by working with a continuous bench-scale plant. The scale-up of the process, even with different raw biomasses as the feedstock, reaction conditions, and operation modes, was in line with the laboratory-scale results, leading to deoxygenation degrees of approximately 60 % with energy yields of approximately 70 % with respect to those of the thermal bio-oil.

The crucial role of clay binders in the performance of ZSM-5 based materials for biomass catalytic pyrolysis

The effect of agglomerating ZrO₂/n-ZSM-5 catalyst with different clays on biomass catalytic pyrolysis is evaluated.

Continuous Hydrothermal Decarboxylation of Fatty Acids and Their Derivatives into Liquid Hydrocarbons Using Mo/Al2O3 Catalyst

In this study, we report a single-step continuous production of straight-chain liquid hydrocarbons from oleic acid and other fatty acid derivatives of interest including castor oil, frying oil, and palm oil using Mo, MgO, and Ni on Al₂O₃ as catalysts in subcritical water. Straight-chain hydrocarbons were obtained via decarboxylation and hydrogenation reactions with no added hydrogen. Mo/Al₂O₃ catalyst was found to exhibit a higher degree of decarboxylation (92%) and liquid yield (71%) compared to the other two examined catalysts (MgO/Al₂O₃, Ni/Al₂O₃) at the maximized conditions of 375 °C, 4 h of space time, and a volume ratio of 5:1 of water to oleic acid. The obtained liquid product has a similar density (0.85 kg/m³ at 15.6 °C) and high heating value (44.7 MJ/kg) as commercial fuels including kerosene (0.78-0.82 kg/m³ and 46.2 MJ/kg), jet fuel (0.78-0.84 kg/m³ and 43.5 MJ/kg), and diesel fuel (0.80-0.96 kg/m³ and 44.8 MJ/kg). The reaction conditions including temperature, volume ratio of water-to-feed, and space time were maximized for the Mo/Al₂O₃ catalyst. Characterization of the spent catalysts showed that a significant amount of amorphous carbon deposited on the catalyst could be removed by simple carbon burning in air with the catalyst recycled and reused.

Evaluation of hydrodeoxygenation reactivity of pyrolysis bio-oil with various Ni-based catalysts for improvement of fuel properties

To improve bio-oil quality, deoxygenation degree and energy efficiency of the process, Ni/C, Ni/SBA-15 and Ni/Al-SBA-15 were synthesized and subjected to hydrodeoxgygenative upgrading process of bio-oil.

Catalytic fast co-pyrolysis of biomass and food waste to produce aromatics: Analytical Py-GC/MS study

In this study, catalytic fast co-pyrolysis (co-CFP) of corn stalk and food waste (FW) was carried out to produce aromatics using quantitative pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), and ZSM-5 zeolite in the hydrogen form was employed as the catalyst. Co-CFP temperature and a parameter called hydrogen to carbon effective ratio (H/C(eff) ratio) were examined for their effects on the relative content of aromatics. Experimental results showed that co-CFP temperature of 600 °C was optimal for the formation of aromatics and other organic pyrolysis products. Besides, H/C(eff) ratio had an important influence on product distribution. The yield of total organic pyrolysis products and relative content of aromatics increased non-linearly with increasing H/C(eff) ratio. There was an apparent synergistic effect between corn stalk and FW during co-CFP process, which promoted the production of aromatics significantly. Co-CFP of biomass and FW was an effective method to produce aromatics and other petrochemicals.

Heterogeneous catalysts for advanced bio-fuel production through catalytic biomass pyrolysis vapor upgrading: a review

Catalytic biomass pyrolysis vapor upgrading presently seems to be a techno-economical process toward production of fuel-like components. However, selection of stable and productive catalyst(s) to yield desirable chemicals with low coke formation is a great challenge.

Catalytic fast pyrolysis of lignocellulosic biomass

We summarize the development of catalysts and provide the current understanding of the chemistry for catalytic fast pyrolysis of lignocelluloses biomass.

Overview of Bio-Oil Upgrading via Catalytic Cracking

Fast pyrolysis of biomass to produce bio-oil is an important technology to utilize lignocellulosic biomass, because the liquid bio-oil is regarded as a promising candidate of petroleum fuels. However, bio-oil is a low-grade liquid fuel, and required to be upgraded before it can be directly utilized in existing thermal devices. Catalytic cracking is an effective way to upgrade bio-oil, which can be performed either on the liquid bio-oil or the pyrolysis vapors. Various catalysts have been prepared and used for catalytic cracking, and they exhibited different catalytic capabilities. This paper will review the recent progress of the catalytic cracking of liquid bio-oil or pyrolysis vapors.

Catalytic pyrolysis of waste rice husk over mesoporous materials

Catalytic fast pyrolysis of waste rice husk was carried out using pyrolysis-gas chromatography/mass spectrometry [Py-GC/MS]. Meso-MFI zeolite [Meso-MFI] was used as the catalyst. In addition, a 0.5-wt.% platinum [Pt] was ion-exchanged into Meso-MFI to examine the effect of Pt addition. Using a catalytic upgrading method, the activities of the catalysts were evaluated in terms of product composition and deoxygenation. The structure and acid site characteristics of the catalysts were analyzed by Brunauer-Emmett-Teller surface area measurement and NH3 temperature-programmed desorption analysis. Catalytic upgrading reduced the amount of oxygenates in the product vapor due to the cracking reaction of the catalysts. Levoglucosan, a polymeric oxygenate species, was completely decomposed without being detected. While the amount of heavy phenols was reduced by catalytic upgrading, the amount of light phenols was increased because of the catalytic cracking of heavy phenols into light phenols and aromatics. The amount of aromatics increased remarkably as a result of catalytic upgrading, which is attributed to the strong Brönsted acid sites and the shape selectivity of the Meso-MFI catalyst. The addition of Pt made the Meso-MFI catalyst even more active in deoxygenation and in the production of aromatics.