Effects of copper ferrites with different prepared methods on the catalytic degradation of lignin with hydrogen peroxide as oxidant is studied. The microstructure, spectral properties and magnetic properties of copper ferrites prepared with five methods were characterized. The results showed that the microcosmic appearance of the catalysts prepared by the five methods was nanoparticles or irregular blocks. All the samples have strong magnetic properties. However the magnetic saturation intensity, residual magnetic intensity and coercivity of copper ferrite prepared by different methods are distinct. The degradation rate and the content of benzene-ring substances were the highest when lignin decomposed under the catalyst of copper ferrite prepared by ethylene glycol assisted sol-gel process, while the content of open-ring substances was the highest when lignin decomposed under the catalyst of copper ferrite made by co-precipitation. Compared with Fenton catalyst, The copper ferrite catalyst easily be separated and good repetitive catalytic performance when used in the lignin degradation. In addition, the crystal structure of copper ferrite play an important role on the catalytic degradation properties of lignin.

Biochar is widely used to remove hexavalent chromium [Cr(VI)] from wastewater through adsorption, which is recognized as a facile, cost-efficient, and high-selectivity approach. In this study, a versatile strategy that combines delignification with subsequent carbonization and KOH activation is proposed to prepare a novel woody biochar from waste poplar sawdust. By virtue of the unique multilayered and honeycomb porous structure induced by delignification and activation processes, the resultant activated carbonized delignified wood (ACDW) exhibits a high specific surface area of 970.52 m² g^–1 with increasing meso- and micropores and abundant oxygen-containing functional groups. As a benign adsorbent for the uptake of Cr(VI) in wastewater, ACDW delivers a remarkable adsorption capacity of 294.86 mg g^–1 in maximum, which is significantly superior to that of unmodified counterparts and other reported biochars. Besides, the adsorption behaviors fit better with the Langmuir isotherm, the pseudo-second-order kinetic model, and the adsorption diffusion model in batch experiments. Based on the results, we put forward the conceivable adsorption mechanism that the synergistic contributions of the capillary force, electrostatic attraction, chemical complexation, and reduction action facilitate the Cr(VI) capture by ACDW.

Sodium lignosulfonate (LS) is a lignin derivative, which has abundant resources and is an environmentally friendly raw material. In this study, cetyltrimethylammonium bromide (CTAB) and stearyltrimethylammonium bromide (STAB) were combined with LS at the isoelectric point for hydrophobic self-assembly. Transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectroscopy, and static contact angle data proved that LS/CTAB could form colloidal spheres, while LS/STAB could not form such spheres. The impact of the molecular weight of LS on the self-assembly of LS/CTAB was investigated by using the TEM, FTIR, and static contact angle data. The obtained results showed that LS/CTAB with 10 000–50 000 Da of LS could form colloidal spheres, while LS/CTAB with 3000–5000 Da of LS could not. In addition, the TEM images revealed that the solvent plays an important role in the morphology of LS/CTAB colloidal spheres. Finally, LS/CTAB colloidal spheres were used for the encapsulation of ibuprofen (IBU). The in vitro release behavior of IBU was proven to be pH-sensitive and exhibited controlled release properties. More than 85% IBU could be preserved in simulated gastric fluid, and over 75% could be released in simulated intestinal fluid. This work provides a theoretical basis for the preparation of LS/CTAB colloidal spheres and facilitates the expansion of its applications as a drug carrier.