In this study, the visible-light-driven photocatalytic regeneration performance of TiO₂-loaded activated carbon (TiO₂/AC) was effectively improved. By carefully controlling the activation condition at 700 °C for 2 h with a 60% H₃PO₄ concentration and 3:1 TBT (tetrabutyl titanate) impregnation ratio, 90.5% of methylene blue (50 mg/L) was removed within 2 h by a low-dose TiO₂/AC (0.5 g/L), which was much higher than those obtained in previous studies on TiO₂/AC. Moreover, the effects of process variables on the microstructure and performance of TiO₂/AC were systematically investigated. The results showed that (1) the long period of activation time effectively inhibited the photogenerated charge carrier recombination and enhanced the regeneration performance of samples; (2) the photogenerated charge carrier recombination rate was lowered initially and then increased as the temperature ascended, whereas the pore volume showed an opposite variation tendency, and thus the adsorption and regeneration performances of samples were improved at 500–700 °C and then weakened at 800 °C; (3) the increase of H₃PO₄ concentration effectively inhibited the charge carrier recombination and had an improvement in the adsorption and regeneration performances of samples; and (4) the photogenerated charge carrier recombination rate and bandgap value of samples decreased initially and then increased with increasing TBT mass ratio, so the regeneration performances of samples were improved initially and then lowered.

Wood-derived activated carbon fibers (WACF) with large mesopore volumes have been developed, which were prepared only by H₃PO₄ as the activator (WACF-P). By carefully controlling the H₃PO₄ concentration at the 10% level and activation temperature at 700°C, the contribution of mesopore to the total pore volume of WACF reached 87%, which is much higher than those obtained in previous studies on ACF. The porosity development mechanism of WACF-P was interpreted based on the data of pore characteristics, crystallite structure, surface elemental constituents, and surface functional groups. The activation effect of H₃PO₄ seems to be mainly relied on the enlargement of the existing defects in the fibers, which are developing to mesopores. Based on the large mesopore volume, the WACF-P have an excellent adsorption property for xylenol orange (XO). In general, the WACF-P are suitable for the adsorption of macromoleculses.

The migration of bound water and free water has been investigated during microwave drying of wood by the time domain nuclear magnetic resonance (TD-NMR) technique. Both the heartwood (hW) and sapwood (sW) of Beijing poplar (Populus beijingensis W. Y. Hsu) and Qingpi poplar (Populus platyphylla T. Y. Sun) were studied. The microwave drying is characterized by a fast drying rate, and there is a linear relation between moisture content (MC) and microwave drying time (t). The drying rate of free water is about 2.7 times more rapid than that of bound water. The spin-spin relaxation time (T2) revealed that most of the water was free water situated in smaller pores. The irregular T2 signal amplitudes of free water in hWs indicated that fractional water in smaller pores was transferred into bigger pores during drying.

Chemical modification is an efficient method for improving the properties of wood. In this study, poplar sapwood was modified via paraformaldehyde, 4,4′-oxydianiline (ODA), and N-methylpyrrolidone solvents through a vacuum-pressure impregnation process. The poplar sapwood underwent a curing process producing the ODA polyhexahydrotriazine polymer, which is a strong thermosetting material. The results showed that the weight percent gain of the modified poplar sapwood was 223.3%. The density of the modified wood specimen increased from 356.8 kg/m³ to 445.0 kg/m³. The water absorption decreased from 159.6% to 0.9% due to the thermosets penetration into the lumen and the cell walls of the wood. Additionally, condensation reactions occurred between the aldehyde groups of the paraformaldehyde and the hydroxyl groups of the poplar wood. The results showed that the modified wood achieved stronger waterproof properties than the unmodified wood.