No abstract

Recently, a solar-driven evaporator has been applied in seawater desalination, but the low stability, high cost, and complex fabrication limit its further application. Herein, we report a novel, low-cost, scalable, and easily fabricated pulp-natural rubber (PNR) foam with a unique porous structure, which was directly used as a solar-driven evaporator after facile surface carbonization. This surface carbonized PNR (CPNR) foam without interface adhesion or modification was composed of a top photothermal layer with light absorption ability and a bottom hydrophilic foam layer with a porous and interconnected network structure. Due to the strong light absorption ability (93.2%) of the carbonized top layer, together with the low thermal conductivity (0.1 W m K–1) and good water adsorption performance (9.9 g g–1) of the bottom layer, the evaporation rate and evaporation efficiency of the pulp foam evaporator under 1 sun of illumination attained 1.62 kg m–2 h–1 and 98.09%, respectively, which were much higher than those of most cellulose-based solar-driven evaporators. Furthermore, the CPNR foam evaporator with high cost-effectiveness presented high light-thermal conversion, heat localization, and good salt rejection properties due to the unique porous structure. Additionally, the CPNR foam evaporator exhibited potential applications in the treatments of simulated sewage, metal ion concentration, and seawater desalination. Its cost-effectiveness was clearly higher than that of most reported evaporators as well. Therefore, this novel, low-cost, and stable pulp foam evaporator demonstrated here can be a very promising solution for water desalination and purification.

Dialdehyde nanocellulose (DANC), obtained via periodate oxidation, has been widely used in foods, cosmetics, and biomedical fields due to its unique characteristics. However, the high-crystallinity and tight structure of cellulose retards the efficiency of periodate oxidation for producing DANC. Herein, a novel sustainable and clean approach with less energy consumption and low cost was developed through LiBr•3H 2 O (LBTH) non-dissolving pretreatment, which can shorten the oxidation time of the followed periodate oxidation and reduce the oxidant consumption. It was shown that the cellulose Iβ structure of hardwood dissolving pulp (HDP) was largely transformed into an amorphous structure after LBTH non-dissolving pretreatment for 30 min, and the corresponding crystallinity of HDP was reduced from 83.2 to 48.7%. After pretreatment for 60 min, the aldehyde group content of the obtained DANC increased by around 30% compared to the control without pretreatment while the operational cost was reduced by 45%. Moreover, the fabricated DANC showed strong antibacterial activity against both Escherichia coli and Bacillus subtilis. LBTH was recovered and reused, and the pretreatment effectiveness was also maintained. This study provides a sustainable, cost-effective, and clean approach for the preparation of DANC and will promote the application of cellulose nanomaterials.