Volume 7, Issue 3

As a rapidly growing area in materials design, the biomimetic approach at the frontier between biology and materials science aims to introduce advanced materials with structural diversities and functional versatilities by mimicking remarkable systems available in nature. Inspired by the fascinating nanostructured assembly existing in the cell walls of different plant species, we designed two fully bio-based green nanomaterials reinforced with renewable polysaccharide nanoparticles in the form of cellulose nanowhiskers (CNWs). In our initial design, the CNWs were incorporated into a cellulose acetate propionate matrix to form a bionanocomposite film, while in the second design the CNWs were entangled within a network of a collagenous medium to introduce a bionanocomposite hydrogel. Tensile and rheological measurements were carried out to study the system’s deformation as subjected to axial force or oscillatory shear. Biocompatibility was tested via incubation of human bone marrow-derived mesenchymal stem cells in vitro . Careful control of the processing conditions resulted in a three-dimensional rigid CNW network percolating within both biopolymer matrices, giving rise to an excellent performance at only a small fraction of CNWs at 3 wt.%. This study reveals that the fully bio-based green nanomaterials with enhanced mechanical percolation could construct a suitable platform for scaffolding in tissue engineering.

A new biocompatible amino-functionalized ionic liquid composed solely of biomaterials was synthesized from taurine and choline hydroxide, and its physical properties (density, viscosity, miscibility and thermal stability) were also determined. The classic base-promoted three-component cyclic condensation of aromatic aldehydes, malononitrile and dimedone was chosen as the test reaction to demonstrate the catalytic activity of choline taurinate ([Ch][Tau]). The catalyst could be recovered and reused several times with no significant loss of activity. As a basic ionic liquid, [Ch][Tau] can extract acidic compounds from immiscible solvents through acid-base interaction. The extraction process of fluorescent dye Rhodamine B was monitored using ultraviolet-visible (UV-Vis) spectroscopy, by which the percentage extraction rate was determined as 95%.

Several pyridopyrimidine derivatives have been synthesized through different synthetic processes. The different physicochemical factors for their synthesis were also discussed. A comparison between the conventional and microwave-assisted synthesis was conducted by comparing total time of reaction and its yield percentage. Most of the produced uracils were established for their anti-inflammatory, analgesic, and antioxidant activities. Compounds 1 and 3 were demonstrated as the best results against DNA damage, whereas compounds 2a and 2b exhibited an effective anti-inflammatory activity. Moreover, the Lipinski rule parameters were calculated for the synthesized compounds. The results indicated that compounds 1 , 2a and 5 have good potential for subsequent development bioactivity.

A comparison study about the extraction and separation of Cu 2+ and Ni 2+ with Lix984N in a microchannel reactor and separating funnel has been conducted. The results showed that, in the microchannel reactor, the overall volumetric mass transfer coefficient of copper was 20 times that of nickel, whereas in the separating funnel, it was only 2 times that of nickel. In addition, the separation coefficient of copper and nickel in the microchannel reactor was 5 times that of the conventional one. Typically, at initial pH=2.5, contact time 1.95 s, volume fraction of extractant Lix984N 15% and within 1.9 g l −1 nickel ion concentration, the extraction rate of copper was higher than 95%, but the nickel was hardly extracted. In comparison, it needed almost 50 s to reach a Cu extraction of 95% in the separation funnel, with more than 5% Ni co-extraction rate. Although the microfluid extraction showed excellent extraction performance, there exists a need to further improve its processing capacity to apply it to industrial production. Furthermore, scaling up the microreactor has become increasingly promising under the fast developing 3D printing technology.

Silver nanoparticles (AgNPs) were synthesized using Aspergillus fumigatus ( A. fumigatus ) mycelia extract via the hydrothermal method. The main reducing and stabilizing groups and components of A. fumigatus extract, such as amine, hydroxyl, amid, protein, enzymes, and cell saccharide compounds, were identified by Fourier transform infrared (FT-IR). Central composition design was used to plan the experiments, and response surface methodology was applied to evaluate of the effects of independent variables, including the amount of the prepared extract (5–7 ml) and heating time (10–20 min) at 121°C and 1.5 bar), on the particle size of the synthesized AgNPs, as manifested in broad emission peak (λ max ). More stable and spherical monodispersed AgNPs, with mean particle size, polydispersity index (PDI) value, and maximum ζ potential value of 23 nm, 0.270, and +35.3 mV, respectively, were obtained at the optimal synthesis conditions using 7 ml of A. fumigatus extract and heating time of 20 min. The synthesized AgNPs indicated high antibacterial activity against both Gram-positive and Gram-negative bacteria.

Barium chloride dihydrate, sodium hydroxide and carbamide were used to prepare barium carbonate (BaCO 3 ) powders using the homogeneous precipitation method. The effects of Ba 2+ concentration, (NH 2 ) 2 CO concentration, NaOH concentration, reaction temperature and reaction time on the particle size and yield of product were mainly researched. The structure and the thermal stability of BaCO 3 powders prepared were analyzed using scanning electron microscopy (SEM) and thermogravimetry-differential scanning calorimetry (TG-DSC), respectively. The particle size distribution of BaCO 3 powders was also characterized using a laser particle size analyzer. The results showed that the BaCO 3 powder prepared has high purity with a needle-like morphology. Based on the results mentioned, this method can be applied in an effective and efficient way for BaCO 3 powder preparation.

Silver nanoparticles (AgNPs) were synthesized using Aloe vera leaf extract as both reducing and stabilizing agents via microwave irradiation method. The effects of the microwave exposure time and the amount of AgNO 3 solution on the mean particle size and concentration of the synthesized AgNPs solution were investigated using response surface methodology. The synthesized AgNPs were characterized by transmission electron microscopy, UV-Vis spectroscopy, and dynamic light scattering. Well-dispersed and spherically fabricated AgNPs with mean particle size (46 nm) and maximum concentration (64 ppm) and zeta potential (+15.5 mV), were obtained at optimal synthesis conditions, using 9 ml of AgNO 3 (1 m m ) and 0.1 ml of Aloe vera extract during microwave exposure time of 360 s. The antibacterial activity of the synthesized AgNPs was tested using Escherichia coli and Staphylococcus aureus bacteria and the obtained results indicated their significant inhibitory effects against these two Gram-negative and Gram-positive bacteria.

CeCl 3 solution was used as a precursor to prepare CeO 2 microspheres by ultrasonic spray pyrolysis (USP). This is a green process that allows the transformation from CeCl 3 to CeO 2 without consuming any precipitant. The prepared material was investigated through various analysis technologies, such as X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high resolution TEM (HRTEM), energy dispersive X-ray spectroscopy (EDS), N 2 adsorption-desorption and X-ray photoelectron spectroscopy (XPS). The prepared sample was confirmed as high purity CeO 2 microspheres, and two different microstructures were observed. The microsphere surface area was 86.5 m 2 /g according to the Brunauer-Emmett-Teller method. The microsphere diameter ranged from 0.09 μm to 3.86 μm and the microsphere surface was covered by numerous nanoparticles. The observed nanoparticles ranged in size from 19 nm to 200 nm as determined from FESEM and HRTEM images. The concentrations of Ce 4+ , Ce 3+ , residual chloride and oxygen vacancy in CeO 2 were studied by relative sensitivity factors based on the XPS results. Finally, the data suggested the possible formation mechanism of the CeO 2 microsphere structure.

The synthesis of oxides has a significant role in their improved properties. This is why a green method is used to gain stable oxide nanoparticles. Zn 2+ doped magnesium oxide (MgO) nanoparticles were synthesized through a green method, extracting Aloe vera latex media. The green method has the advantages of being a cost-effective, innocuous, eco-friendly method. Firstly, thanks to the structure of Aloe vera latex, its extract has an important role in morphology, and crystal size of MgO structure, which leads to homogenous nanoparticles dispersion. The elliptical particles with ranges from 45 nm to 65 nm were observed by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). Furthermore, the effect of calcination temperature was investigated, showing that increasing calcination temperature made larger particles with sharper peaks in X-ray diffraction (XRD) analysis. The strain value (ε) and crystallite size by Williamson-Hall (nm), dislocation density, and crystallinity index were evaluated. Finally, energy dispersive X-ray spectroscopy (EDS) confirmed the doping of Zn 2+ in MgO nanoparticles. Fourier transform infrared (FT-IR) and HRTEM analyses were also used.

The ZnO:xCu photocatalyst was prepared with reacting media, namely, water method followed by wet impregnation to deposit Cu on the ZnO nano particles. X-ray diffraction was used to perform crystallography and the determination of the ZnO:xCu particle size. Fourier transform infrared was employed for the detection of chemical bonds in the synthesized photocatalyst. The nanoparticle morphology was studied by field emission scanning electron microscope. The elemental composition of the synthesized catalysts was evaluated with X-ray fluorescence technique. Diffuse reflection spectroscopy analysis was performed to investigate the light absorption of the ZnO:xCu catalysts. The photocatalytic activity of the prepared ZnO:xCu nanoparticles was studied for the removal of nitrate from the aqueous solution of ammonium nitrate (50 mg·l −1 ) under UV irradiation. Results indicated that the ZnO:xCu photocatalyst has high photocalytic activity to remove nitrate from water. Moreover, complete degradation was achieved after 2.5 h.

Hydrotreating of 10% fatty acid methyl ester (FAME) blended in gas oil was carried out by an NiMo-S/alumina catalyst and performed at an elevated temperature (300–400°C), a space velocity of 0.7–1.5 1/h and pressure 5 MPa. The gas oil was a straight run North Sea crude oil containing 295 ppm sulfur content which was desulfurized in a hydrotreating upgrading process. The physicochemical properties following hydroprocessing of FAME showed that sulfur content was reduced to 3 ppmw, with an increase in aromatic content and cloud point. It was confirmed that decarboxylation depends on temperature and space velocity and decarbonylation depends on temperature, but not on space velocity of feed. High sulfur content in the feedstock supports slow deactivation of the catalyst and low coke formation.

The aim of this paper is to discuss the usability of a newly designed partially stirred horizontal anaerobic bioreactor made from triple layer bag material Sioen B6070 and heated by circulating hot air. For verification of the possibility of processing typical agricultural fibrous substrate at relatively high solids content in this type of reactor, the semi-continuous mesophilic (40±3°C) anaerobic digestion of corn silage of KWS Atletico cultivar was conducted. The reactor with a total volume of 0.7 m 3 provided 0.5 m 3 working volume. Liquid slurry from the 1st stage of the agricultural biogas station Pustejov II was used as inoculum. The silage dosage was performed so that the reactor reached high methane production intensity at low volumetric production of the digestate for 120 days. The average organic loading reached 4.27 kg VS m −3 d −1 while the average hydraulic retention time decreased to 85 days. The dry biogas production intensity was 3.42 m N 3 m −3 d −1 with an average methane content of 52.5 vol%. The specific methane production from corn silage was 0.419 m N 3 kg VS −1 . At the end of the test, the digestate contained 13–14 wt% of total solids (TS) and 82–85 wt% of volatile solids in TS. The bag-type digester with hot air heating can be used by small farmers where there is no viable biogas cogeneration.