Xingxiang Ji

Characterization of Lignin Extracted from Willow by Deep Eutectic Solvent Treatments

Purity, morphology, and structural characterization of synthesized deep eutectic solvent (DES)-lignins (D6h, D9h, D12h, D18h, D24h) extracted from willow (Salix matsudana cv. Zhuliu) after treatment with a 1:10 molar ratio of choline chloride and lactic acid at 120 °C for 6, 9, 12, 18, and 24 h were carried out. The purity of DES-lignin was ~95.4%. The proportion of hydrogen (H) in DES-lignin samples increased from 4.22% to 6.90% with lignin extraction time. The DES-lignin samples had low number/weight average molecular weights (1348.1/1806.7 to 920.2/1042.5 g/mol, from D6h to D24h) and low particle sizes (702–400 nm). Atomic force microscopy (AFM) analysis demonstrated that DES-lignin nanoparticles had smooth surfaces and diameters of 200–420 nm. Syringyl (S) units were dominant, and total phenolic hydroxyl content and total hydroxyl content reached their highest values of 2.05 and 3.42 mmol·g−1 in D12h and D6h, respectively. β-Aryl ether (β-O-4) linkages were eliminated during DES treatment.

Synthesis, Characterization, and Photocatalytic Properties of Bamboo Charcoal/TiO2 Composites Using Four Sizes Powder

Visible-light-active bamboo biochar/TiO2 composites were fabricated by the calcination method using C16H36O4Ti as the titanium source and bamboo powder with different sizes as the carbon source. The TiO2 nanoparticles were observed to disperse onto the surface of bamboo biochar fiber. The sizes of the bamboo powder played an important role in the microstructures and the properties of bamboo biochar/TiO2 composites. The bamboo biochar/TiO2 composites displayed the photocatalytic activities both under visible light irradiation and UV irradiation. The adsorption isotherms better fitted Freundlich isotherm models and the photodegradation reactions followed pseudo-first-order kinetics. Bamboo charcoal/TiO2 composites exhibited high stability after up to four cycles. This research could pave the way for high-value applications of biomass in the environmental field.

Production and Characterization of Cellulose Nanofibrils from Different Chemical and Mechanical Pulps

In this study, mechanical fibrillation for the production of cellulose nanofibrils (CNF) from chemical and mechanical pulps with different chemical compositions was studied. To investigate the effect of nanofibrillation on wood pulps by the grinder, the nanofibrils obtained from grinded pulp were characterized with morphology, particle size distribution, apparent viscosity in aqueous solution, degree of crystallinity, and water retention capacity. The results showed that the low lignin-containing unbleached kraft pulp (UKP) exhibited good performance for fibrillation, resulting in CNF with high viscosity, high water retention value, and small particle size. However, the fibrillation of high lignin-containing chemi-thermomechanical pulp was the most inefficient which resulted in heterogeneous materials with relatively low viscosity, low water retention value, and large particle size compared to chemical pulps. Furthermore, bleached softwood pulp from radiata pine was found to be much faster and for easier fibrillation compared to the bleached hardwood pulp from acacia due to the more rigid structure of hardwood fibers.

Facile synthesis of elemental silver by the seed nucleus embedding method for antibacterial applications

The preparation method of Silver (Ag)-loaded cellulose paper based on the formation of seed nuclei has been proposed as a functional material with high antibacterial performance. Metal palladium (Pd) was employed for the formation of seed nuclei, followed by sodium potassium tartrate tetrahydrate reduction to create Pd–Ag-cellulose paper. The properties in term of micro morphology, distribution of silver particles, antibacterial activity and silver release behavior were investigated. The results verified the formation of Pd-nucleus on surface of fiber, and revealed that silver particles were steadily deposited on the fibers based on the seed nuclei embedded. Pd–Ag-cellulose paper, comparing with Ag-cellulose paper produced with direct deposition method, exhibited a thick closely silver layer and uniform distribution of silver particles. The antibacterial test indicated that the lethality rate of Pd–Ag-cellulose paper against E. coli is 99.92% which is very close to that of Ag-cellulose paper (99.93%). Nevertheless, the silver release regression equation provided a high slope value (0.075) to Ag-cellulose paper, which explains a rapid release of silver. Pd–Ag-cellulose paper, by contrast, the slope value is only 0.021, and that indicates the silver slower release was achieved. Ag-loaded cellulose paper prepared using the proposed method shows the prominent properties in silver loading, antibacterial and silver slow-release.Graphical abstract