Volume 14 Issue 2

A novel magnetic anticancer drug carrier based on cellulose, guar gum, and Fe3O4 hydrogel microspheres was synthesized by chemical crosslinking. These microspheres were crosslinked with epoxy chloropropane and loaded with 5-fluorouracil (5-fu). The effect of the ratio of cellulose to guar gum on bead size, drug loading, and in vitro release behaviors were investigated. The influence of the magnetic content on drug loading and in vitro release behaviors were also evaluated. The magnetic hydrogel microspheres were characterized via an optical microscope, Fourier transform infrared spectroscopy, swelling behavior analysis, vibrating sample magnetometer, and ultraviolet absorption spectroscopy. The results showed that as the ratio of cellulose to guar gum increased from 3:1 to 5:1, the particle size increased from 395 to 459 um. Moreover, the drug loading capacity, encapsulation efficiency, and in vitro release behavior were influenced by the ratio of cellulose/guar gum and Fe3O4 content. Finally, the Fe3O4 particle had an adsorption effect on the drug, thereby reducing the maximum cumulative release.

Inorganic salt is a promising stabilizer in the hydrothermal synthesis of porous carbon materials. A three-dimensional palladium-loaded (Pd-loaded) lignin carbonaceous material with a porous structure was developed via hydrothermal carbonization, with lignin as not only a carbon source but also a reducing and stabilizing agent for palladium nanoparticles (Pd NPs) and then with LiCl as the hard template and porogen. The porogen-induced Pd-loaded carbonaceous material displayed an orderly pore structure with more porosity than the porogen-free Pd-loaded carbonaceous material. Subsequently, the porogen-induced Pd-loaded carbonaceous materials were transferred to an aqueous phase filter and mixed with reactants in a syringe as catalysts. The catalyst exhibited excellent catalytic performances in the reduction reaction of 4-nitrophenol to 4-aminophenol by NaBH4, with a rate constant of 0.11 min-1, which was higher than that of the porogen-free Pd-loaded carbonaceous material. In this study, LiCl was employed as the hard template and porogen to construct the porous carbonaceous structure and improve the porosity by stabilizing the pore structure and minimizing collapse, which provided a new way to synthesize lignin porous carbonaceous material.

The objective of this study was to characterize the performance of composite wood blocks (CWB) by testing internal bonding, nail extraction resistance, and water absorption. The CWB were glued with two wood adhesives, polyvinyl acetate (PVAc), and urea formaldehyde (UF), modified with 1% nanocrystalline cellulose (NCC). Three tropical species were employed: Vochysia ferruginea, Cordia alliodora, and Gmelina arborea. In addition, the original European pallet in the static flexure test was evaluated. The results showed that the internal bonding relative to solid wood blocks (SWB) increased with both adhesives. Meanwhile, the CWB of V. ferruginea with UF and C. alliodora with PVAc showed the greatest resistance to nail extraction, while in G. arborea, the NCC increased the resistance to nail extraction. The CWB with modified adhesives absorbed more moisture, particularly with PVAc, compared with the SWB. In static flexure tests of the pallets fabricated with CWB, the load at the limit of proportionality and the maximum load increased, while deflections were lower, compared with SWB. The results showed the potential of utilizing NCC in CWB fabricated with tropical species.

Cellulose aerogel adsorbent (CAA), a novel, effective, and green adsorbent, which contains tertiary amino groups, was surface modified by poly(N,N-dimethyl aminoethyl methacrylate) and sol-gel methods. It has both adsorption and reduction functions and can be utilized to remove chlorate (ClO3-) from drinking water. In the static adsorption experiments, the CAA effectively removed ClO3-, even at low initial concentrations. The adsorption kinetics showed that the adsorption equilibrium could be reached within 20 min. Additionally, the experimental data was fitted to several adsorption models, including the pseudo-first-order kinetic model, pseudo-second-order kinetic model, intra-particle reaction diffusion equation, and Langmuir and Freundlich isotherms.

Cellulose nanofibers were isolated from oil palm empty fruit bunch by delignification using Marasmius sp. and subsequently treated by solid state fermentation using Trichoderma sp. This method used pH values of 4.8, 5.5, and 7 and temperatures of 28 °C, 32 °C, and 37 °C for 7 d. Scanning electron microscopy, Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and particle size analysis were performed to determine the properties of the isolated cellulose nanofibers. Results showed that chemical analysis by FTIR, lignin was completely removed from the EFB. It was found that the combination of pH 5.5 and incubation temperature 37 °C were favorable for the SSF process to isolate cellulose nanofibers from oil palm EFB fiber. SSF processing resulted in smooth morphological structures, with a fiber diameter range of 32.6 nm to 36.4 nm.

Cellulose nanocrystals (CNCs) were modified with methyl methacrylate (MMA) to improve the properties of the resulting three-dimensional (3D) stereolithography printed CNC/methacrylate (MA) resin composites. The dispersibility of the MMA-modified CNCs (MMA-CNCs) was substantially improved, as evidenced by the limited precipitation in the MA solution. Thermal gravimetry and differential scanning calorimetry measurements showed that the pyrolytic temperature of the MMA-CNC was 110 °C higher than that of the CNCs; the pyrolytic temperature and glass transition temperature of the resulting MMA-CNC/MA composites were higher than those of the CNC/MA. The tensile strength and modulus of the MMA-CNC/MA composites were improved by up to 38.3 MPa and 3.07 GPa, respectively, compared to those of the CNC/MA composites. These results demonstrated that the modification of CNC with MMA is a feasible approach to substantially improve the mechanical properties and thermal stability of the resulting MA-based composites.

To utilize the process water during ethanol fermentation from food waste saccharification broth, the water obtained after three types of technology—methane fermentation, electrodialysis, and microbial fuel cell—were utilized in recycle fermentation in food waste ethanol fermentation. The food waste methane water (FWS), electrodialysis water (FEW), and microbial fuel cell water (FWM), were compared with tap water in terms of ethanol fermentation, volatile fatty acid production, and other parameters. The results indicated that fermentation time was reduced by 50% using both FEW and FWM recycling. Among the different recycled water, FEW recycling in ethanol fermentation motivated yeast growth, yielding the highest ethanol value of 47 g/L. The pH changes in the fermentation systems during 60 h using the different recycled waters were within the optimal range of ethanol fermentation (pH 4.0 to 5.0). Moreover, the highest content of acids found in the fermentation systems were 15 g/L and 11 g/L for lactic and formic acid, respectively, which was less than the inhibition values reported. There was no significant inhibition of ethanol fermentation system due to the presence of VFAs. This study will aid the development of an integrated treatment plant for food waste and biofuel production.

The yields in bioconversion of residues produced in the Cameroon food industry to liquid and gaseous biofuels were evaluated and the potential of these residues as feedstock for renewable energy production in Cameroon were assessed. Residues generated after processing avocado, cocoa, and peanut crops were converted at laboratory-scale to second-generation gaseous biofuels (biogas) and liquid biofuels (ethanol). Mechanical (milling), thermal-chemical (steam-NaOH), and microwave pretreatments were applied before hydrolysis of biomass using cellulolytic enzymes. Cellulosic sugars production potential was also assessed. The energy conversion rate was higher when anaerobic digestion technology was applied to convert the tested biomass to methane. The total Cameroon potential under anaerobic digestion technology is over 330,000 m3, which represents 28% from oil consumption or 5.39% from electricity consumption when lignocellulosic ethanol technology was applied. The national potential was assessed up to 200,000 kg, representing 17% from oil consumption in transport or 3.19% from electricity consumption. Overall, the share of energy potential of the tested residual biomass is important when compared to fossil fuel consumption in Cameroon and represents an important potential feedstock for electricity production.

The development of materials that offer environmental comfort inside buildings, through adequate thermal and acoustic behavior, has been as relevant as the search for raw materials of renewable origin. In this context, this study produced and characterized panels made with Pinus sp. waste materials, which were treated with a copper chrome boric oxide preservative and a castor-oil based polyurethane resin. The physical and mechanical properties of the panels were evaluated according to the ABNT NBR 14810 standard (2013). The panel porosity was investigated by scanning electron microscopy (SEM) and mercury intrusion porosimetry techniques. The sound absorption was analyzed by a reverberation chamber and thermal conductivity by the modified fractionated column method. Samples with a higher pressing pressure (4 MPa) during the manufacturing presented lower thickness swelling and higher mechanical properties in static bending. Panels made with a lower press pressure (2.5 MPa) resulted in a higher porosity volume (55.7%). The more highly porous panels were more acoustically efficient, with a sound absorption coefficient close to 0.8 at 3.2 kHz, and they had a better thermal conductivity performance.The potential of these panels for application where sound absorption and thermal insulation are prioritized is thus observed.

Wood-based solar steam generation holds great promise in alleviating fresh water crises due to its advantages: light absorbability, thermal management, water transpiration, and water evaporation. Although tremendous efforts have been made to improve wood-based solar steam generation devices, they mainly have focused on the optimization of photothermal materials to optimize light absorbability and thermal management to enhance efficiency of steam generation. This research demonstrates that delignified wood (DL-wood) can further improve the efficiency of steam generation via increasing both the water transportation and water evaporation. The results show that after placing carbon nanotubes (CNTs) on DL-wood, the efficiency of steam production is higher than that of natural wood coated with CNTs by 20% under ambient sunlight conditions. DL-wood with CNTs has the following advantages: (1) it is stable, available, and easy to extend; (2) it does not pollute the environment and will not cause discoloration or dregs when used; and (3) it is a promising efficiency-enhancing solution for renewable and portable solar power generation.