Improved Mechanical Properties of Jute Fiber/Polypropylene Composite with Interface Modified by Sodium Lignosulfonate

How to improve the interfacial compatibility between polar fibers and non-polar polymer matrices is still a challenge for the application of natural fiber/polymer composites. In this study, the jute fibers (JF) was firstly treated by coating sodium lignosulfonate (SL) layer, then the JF-SL/polypropylene (PP) composite was fabricated by injection molding technique. The morphology, surface chemical property, surface energy, mechanical properties of JF and JF-SL, as well as the mechanical properties of JF/PP and JF-SL/PP composites were systematically studied. The results showed that the SL coating layer successfully formed on the surface of JF, and the dipole bond and hydrogen bond interaction occurred between the SL and JF. Compared with JF/PP composite, the tensile modulus, tensile strength, flexural modulus and flexural strength of JF-SL/PP composite increased by 8.25%, 16.79%, 16.87% and 19.71%, respectively, due to the enhancement of the interfacial binding force between JF-SL and PP matrix. These results indicate that SL possesses great potential to be used as a compatibilizer to effectively improve the mechanical properties of JF-SL/PP composite. It could provide an reference basis for the feasibility of SL used as a compatibilizer for natural fiber/polymer composites.

Plasma Treatments to Improve the Bonding of Thermo-Treated Cherry Wood

Thermal treatment can significantly improve the dimensional stability of wood, but it will decrease the bonding strength. In this work, the bonding strength of thermo-treated cherry wood boards was improved by plasma treatment. The change of wettability, surface morphology, and surface chemical property of cherry wood before and after plasma treatment was investigated by water contact angle measurement, Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The plasma treatment significantly improved the wettability of thermo-treated cherry wood by decreasing its water contact angle from 109.95° to 53.18°. N2 or O2 was used as the plasma atmosphere, and it was found that N2 plasma treatment afforded cherry wood a rougher surface. The AFM roughness of cherry wood was increased from 19 nm to 31.9 nm after N2 plasma treatment. XPS results revealed an additional C–N group for N2 plasma treatment and the content of C=O, O–C–O, and O–C=O increased for O2 plasma treatment, respectively, indicating that the surface chemical property of cherry wood was modified. Due to the surface character, the bonding strength increased by 21.17% for N2 plasma treatment and 15.32% for O2 plasma treatment.

Modified powder activated carbon-catalyzed ozonation of humic acid: influences of chemical and textural properties

A modification method that combines thermal and oxidation treatments was used to improve catalytic activity of activated carbon (AC) which catalyzed ozonation of the aquatic contaminant humic acid (HA). As a consequence of modifying virgin AC, modified AC (ACN2O2N2) had good catalytic performance for ozonation of HA. Apparent first-order rate constants (kapp) were ACN2O2N2 (7.88 × 10−3 s−1) > virgin AC (3.28 × 10−3 s−1). This change was discussed in terms of three factors: textural property, graphitization degree, and surface chemical property. From analysis results, it was deduced that the surface chemical property (the concentration of surface groups) was the main factor that influenced catalytic activity. An increase in the concentration of hydroxyl groups on AC enhanced catalytic activity of AC in ozonation of HA. Effects of phosphate (both a ligand and a strong Lewis base) further confirmed that Lewis acid sites (hydroxyl groups) were the active centers for free radical reaction in catalytic ozonation of AC.

Capacitive Performance of Ordered Mesoporous Carbons in Ionic Liquids

Ordered mesoporous carbons (BOMC) were prepared by doping boric acid using a hard-templating method, while a CMK-3 carbon (OMC) was also prepared for comparison. The capacitive performance of these two carbons was investigated in ionic liquid of EMImBF4 and EMImTSFI. As demonstrated by the structure analysis, BOMC possesses almost same surface area and pore size as OMC, while the former carbon possesses higher content of oxygen-containing groups. In ionic liquid electrolyte, the carbons mainly show typical electric double layer capacitance, and the capacitance retention ratio and ion diffusion of electrolyte is determined to the surface chemical property. BOMC present visible pseudo-capacitance due to the oxygenated groups in hydrophilic EMImBF4, while no visible pseudo-capacitive behavior was observed in hydrophobic EMImTSFI.

Adsorptive Removal of Dibenzothiophene in Diesel Fuel on an Adsorbent from Rice Hull Activated by Phosphoric Acid

Rice hull (designated with RH) was activated by phosphoric acid to prepare an adsorbent for the removal of sulfur-containing compounds from diesel fuel. Adsorption tests for both, a 300 µg.g-1 dibenzothiophene (DBT)-containing n-octane solution using as model oil and a commercial hydro-treated diesel fuel, were performed to elucidate the effect of varying phosphoric acid to RH ratio, treating temperature and the removal of silica from the adsorbent on the combination of the textural structure, surface chemical property and adsorption capacity. It was indicated that high surface area and micro-pore volume of the adsorbent favored the adsorption of DBT and its derivatives. Richening of oxygen-containing compounds on the adsorbent surface was advantageous to the adsorption and removal of DBTs. At a phosphoric acid and RH weight ratio of 3:1 by using a two-step treatment, a satisfactory adsorbent with an adsorption capacity of 28.89 mg S/g was successfully prepared. If the silica in the adsorbent was further removed, the product exhibited the highest performance, reaching 30.43 mg S/g for the model oil and 21.79 mg S/g for the commercial diesel fuel. Both the textural structure and the surface chemical property like acidic groups of a RH-based adsorbent play important roles in its adsorption behaviors, and the formation of donor-acceptor complexes between surface acidic groups and DBT may probably benefit DBT adsorption capacity.