Zhengrong Gu

Hydrodeoxygenation of prairie cordgrass bio-oil over Ni based activated carbon synergistic catalysts combined with different metals

Bio-oil can be upgraded through hydrodeoxygenation (HDO). Low-cost and effective catalysts are crucial for the HDO process. In this study, four inexpensive combinations of Ni based activated carbon synergistic catalysts including Ni/AC, Ni-Fe/AC, Ni-Mo/AC and Ni-Cu/AC were evaluated for HDO of prairie cordgrass (PCG) bio-oil. The tests were carried out in the autoclave under mild operating conditions with 500psig of H2 pressure and 350°C temperature. The catalysts were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) and transmission electron microscope (TEM). The results show that all synergistic catalysts had significant improvements on the physicochemical properties (water content, pH, oxygen content, higher heating value and chemical compositions) of the upgraded PCG bio-oil. The higher heating value of the upgraded bio-oil (ranging from 29.65MJ/kg to 31.61MJ/kg) improved significantly in comparison with the raw bio-oil (11.33MJ/kg), while the oxygen content reduced to only 21.70-25.88% from 68.81% of the raw bio-oil. Compared to raw bio-oil (8.78% hydrocarbons and no alkyl-phenols), the Ni/AC catalysts produced the highest content of gasoline range hydrocarbons (C6-C12) at 32.63% in the upgraded bio-oil, while Ni-Mo/AC generated the upgraded bio-oil with the highest content of gasoline blending alkyl-phenols at 38.41%.

Catalytic cracking of inedible camelina oils to hydrocarbon fuels over bifunctional Zn/ZSM-5 catalysts

Catalytic cracking of camelina oils to hydrocarbon fuels over ZSM-5 and ZSM-5 impregnated with Zn2+ (named bifunctional catalyst) was individually carried out at 500 °C using a tubular fixed-bed reactor. Fresh and used catalysts were characterized by ammonia temperature-programmed desorption (NH3-TPD), X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and nitrogen isothermal adsorption/desorption micropore analyzer. The effect of catalysts on the yield rate and qualities of products was discussed. The loading of Zn2+ to ZSM-5 provided additional acid sites and increased the ratio of Lewis acid site to Brønsted acid site. BET results revealed that the surface area and pore volume of the catalyst decreased after ZSM-5 was impregnated with zinc, while the pore size increased. When using the bifunctional catalyst, the pH value and heating value of upgraded camelina oils increased, while the oxygen content and moisture content decreased. Additionally, the yield rate of hydrocarbon fuels increased, while the density and oxygen content decreased. Because of a high content of fatty acids, the distillation residues of cracking oils might be recycled to the process to improve the hydrocarbon fuel yield rate.

Recombinant botulinum neurotoxin A heavy chain-based delivery vehicles for neuronal cell targeting

The long half-life of botulinum neurotoxin serotype A (BoNT/A) in cells poses a challenge in developing post-exposure therapeutics complementary to existing antitoxin strategies. Delivery vehicles consisting of the toxin heavy chain (HC), including the receptor-binding domain and translocation domain, connected to an inhibitory cargo offer a possible solution for rescuing intoxicated neurons in victims paralyzed from botulism. Here, we report the expression and purification of soluble recombinant prototype green fluorescent protein (GFP) cargo proteins fused to the entire BoNT/A-HC (residues 544-1295) in Escherichia coli with up to a 40 amino acid linker inserted between the cargo and BoNT/A-HC vehicle. We show that these GFP-HC fusion proteins are functionally active and readily taken up by cultured neuronal cells as well as by neuronal cells in mouse motor nerve endings.

Graphitized activated carbon based on big bluestem as an electrode for supercapacitors

Activated carbon based on biochar is an attractive material for energy storage in terms of its high specific capacitance and low cost. The activated carbon samples were based on big bluestem biochar, which is the waste from a thermochemical process optimized for bio-oil production. Sodium bicarbonate, sodium hydroxide and potassium hydroxide were used as reagents to obtain the activated carbon samples. The surface area and pore structure of the activated carbon, characterized by the N2 adsorption–desorption method, were firmly in conjunction with those of the reagents. The high specific surface area (2490 m2 g−1) of the activated carbon was achieved by the activation of potassium hydroxide. Scanning electron microscopy and Raman spectroscopy were used to test the microstructure and crystallographic orientation of the carbon samples. Concerning the G band (1580 cm−1) and the ratio of this with the D band (1338 cm−1), which was 0.55, the Raman spectrum indicated that the potassium hydroxide activated carbon sample contained sp2 carbon. The 2D (2680 cm−1) band showed that this activated carbon has similar properties to multilayer graphene. The cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy were measured after the activated carbon was assembled into supercapacitors. The potassium hydroxide activated carbon sample presented a high specific capacitance of 283 F g−1, and a relatively low inner resistance of 2 ohm.

Nitrogen-modified biomass-derived cheese-like porous carbon for electric double layer capacitors

Lignin, an abundant biomass constituent in nature, was modified by pyrrole to produce nitrogen-doped porous carbon. The porous carbon was efficiently activated through simultaneous chemical and physical reactions using potassium hydroxide as an activation agent during the heat treatment. Surface area analysis showed that the activated carbon possessed mesopores (∼15 nm) and a large specific surface area of 2661 m2 g−1, with a cheese-like morphology. Electrochemical double layer capacitors fabricated using the activated carbon as an electrode material showed a specific capacitance of 248 F g−1 at a low current density of 0.1 A g−1 and 211 F g−1 at a high current density of 10 A g−1 in 6 M KOH solution. Charge and discharge for 1000 cycles at different current densities ranging from 0.1 to 10 A g−1 confirmed excellent specific capacitance retention and good cycling stability. This work demonstrates that the nitrogen-doped cheese-like porous activated carbon is a promising electrode material for electric double layer capacitors.

Adsorption of butanol vapor on active carbons with nitric acid hydrothermal modification

Butanol can be produced from biomass via fermentation and used in vehicles. Unfortunately, butanol is toxic to the microbes, and this can slow fermentation rates and reduce butanol yields. Butanol can be efficiently removed from fermentation broth by gas stripping, thereby preventing its inhibitory effects. Original active carbon (AC) and AC samples modified by nitric acid hydrothermal modification were assessed for their ability to adsorb butanol vapor. The specific surface area and oxygen-containing functional groups of AC were tested before and after modification. The adsorption capacity of unmodified AC samples was the highest. Hydrothermal oxidation of AC with HNO3 increased the surface oxygen content, Brunauer-Emmett-Teller (BET) surface area, micropore, mesopore and total pore volume of AC. Although the pore structure and specific surface area were greatly improved after hydrothermal oxidization with 4M HNO3, the increased oxygen on the surface of AC decreased the dynamic adsorption capacity.

Quantification of Physical and Chemical Properties, and Identification of Potentially Valuable Components from Fuel Ethanol Process Streams

ABSTRACT Wider exploration of ethanol coproduct uses is necessary as the ethanol industry continues to face challenges. Currently, process streams such as thin stillage and condensed distillers solubles (CDS) are processed into distillers dried grains with solubles and used as animal feeds, but other higher value opportunities may exist. The objective of this study was to identify chemical components and quantify physical properties of CDS and thin stillage. Protein, organic acid, and sugar profiles were determined. Zein protein was identified, and glycerol was determined to have a concentration of 18.8 g/L in thin stillage and 63.2 g/L in CDS. Physical properties including density, thermal conductivity, thermal diffusivity, and rheological behaviors were also examined. Thermal conductivity of thin stillage and CDS was approximately 0.54 and 0.45 W/m°C, respectively. Quantification of the physical properties and identification of the chemical constituents pave the way for exploration of new value-added us...

Recovery of Recombinant Proteins from Plants Using Aqueous Two-Phase Partitioning Systems: An Outline

Transgenic plants producing recombinant proteins are a potential low-cost substitute for complex bioreactors. However, the development of new robust downstream processes to improve protein recovery and isolation from plant feedstock is critical to promote this new technique because downstream processing costs typically contribute to more than 80 % of the total cost. Polishing separation platforms for protein purification, such as chromatography and membrane filtration, have been well established, while little attention has been allocated to initial concentration and separation procedures. In this chapter, application of aqueous two-phase partitioning (ATPP), as an attractive alternative to traditional processes for recovering and isolating target proteins from plant green tissues or seeds, as well as the main advances reported in literature concerning ATPP for the isolation and purification of proteins from plant feedstock are reviewed. The potential application of ATPP as an integrated extraction and isolation step and isolation step after extraction or protein characterization method is discussed separately. The connection of ATPP with traditional protein separation processes is discussed. The separation mechanisms of ATPP are explained based on surface properties of proteins and polymer systems. Finally, the future trends in applying ATPP for protein separation are discussed.

Porous carbon derived from aniline-modified fungus for symmetrical supercapacitor electrodes

N incorporated carbon materials are proven to be efficient EDLCs electrode materials. In this work, aniline modified fungus served as a raw material, and N-doped porous activated carbon is prepared via an efficient KOH activation method. A porous network with a high specific surface area of 2339 m2 g−1 is displayed by the prepared carbon material, resulting in a high accessible surface area and low ion diffusion resistance which is desirable for EDLC electrode materials. In assembled EDLCs, the N–AC based electrode exhibits a specific capacitance of 218 F g−1 at a current density of 0.1 A g−1. Besides, excellent stability is displayed after 5000 continuous cycles at different current densities ranging from 0.1 to 10 A g−1. The present work reveals a promising candidate for electrode materials of EDLCs.

Separation of glucosinolates from Camelina seed meal via membrane and acidic aluminum oxide column.

Glucosinolates are secondary metabolites, as well as representative bioactive therapeutic small molecules, which are found in Camelina seed meal. In this study, an ultrafiltration (UF) membrane was employed to remove protein after ethanol extraction of glucosinolates. After UF, preparative chromatography, based on acidic aluminum oxide, was used to further purify glucosinolates. The impact of different concentrations of NaCl elution buffer at 0.2, 0.5, and 1.0 mol/L on the recovery of glucosinolates was evaluated. The results indicated that elution with a 1.0 mol/L salt solution recovered 91.0% of glucosinolates from the UF permeate. The glucosinolate yield recovered from the seed meal was 9.52 µmol/g. High-performance liquid chromatography analysis showed that only the major glucosinolates peaks at retention times 13.0, 17.6, and 19.2 min appeared. This result indicated that most impurities of UF permeate were removed after anion exchange. Traditional protein removal methods for recovering glucosinolates, such as using heavy metal salt precipitate, are expensive and environmentally harmful. The glucosinolate separation process described herein can be used as a model process for purifying other natural bioactive chemicals from biofuel processing and other agricultural residues.