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Petroleum-based plastics, such as PP, PE, PVC, etc., have become an important source of environmental pollution due to their hard degradation, posing a serious threat to the human health. Isolating nanocellulose from abundant biomass waste resources and further integrating the nanocellulose into hydrophobic transparent film (i.e., nanopaper), to replace the traditional nondegradable plastic film, is of great significance for solving the problem of environmental pollution and achieving sustainable development of society. This study respectively extracted nanocellulose from the branches of Amorpha fruticosa Linn., wheat straw, and poplar residues via combined mechanical treatments of grinding and high-pressure homogenization. Among them, the nanocellulose derived from the Amorpha fruticosa has a finer structure, with diameter of about 10 nm and an aspect ratio of more than 500. With the nanocellulose as building block, we constructed hydrophilic nanopaper with high light transmittance (up to 90%) and high mechanical strength (tensile strength up to 110 MPa). After further hybridization by incorporating nano-silica into the nanopaper, followed by hydrophobic treatment, we built hydrophobic nanopaper with transmittance over 82% and a water contact angle of about 102° that could potentially replace transparent plastic film and has wide applications in food packaging, agricultural film, electronic device, and other fields.

With the enhancement of people's environmental awareness, waterborne polyurethane (PU) paint-with its advantages of low release of volatile organic compounds (VOCs), low temperature flexibility, acid and alkali resistance, excellent solvent resistance and superior weather resistance-has made its application for wood furniture favored by the industry. However, due to its lower solid content and weak intermolecular force, the mechanical properties of waterborne PU paint are normally less than those of the traditional solvent-based polyurethane paint, which has become the key bottleneck restricting its wide applications. To this end, this study explores nanocellulose derived from biomass resources by the 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidation method to reinforce and thus improve the mechanical properties of waterborne PU paint. Two methods of adding nanocellulose to waterborne PU-chemical addition and physical blending-are explored. Results show that, compared to the physical blending method, the chemical grafting method at 0.1 wt% nanocellulose addition results in the maximum improvement of the comprehensive properties of the PU coating. With this method, the tensile strength, elongation at break, hardness and abrasion resistance of the waterborne PU paint increase by up to 58.7%, ~55%, 6.9% and 3.45%, respectively, compared to the control PU; while the glossiness and surface drying time were hardly affected. Such exploration provides an effective way for wide applications of water PU in the wood industry and nanocellulose in waterborne wood coating.

Heavy metal pollution is one of the most serious environmental problems, posing threats to human health. Here, we developed a magnetic hybrid aerogel by integrating nanocellulose and ferroferric oxide (Fe3O4) nanoparticles for effectively adsorbing heavy metal ions from water and realizing controllable recovery under magnetic condition. The magnetic behavior and adsorbing capacity of the hybrid aerogel on removal of heavy metal chromium (Cr)(VI) ion were examined. Results show that the ferroferric oxide nanoparticles physically adsorb the nanocellulose, each of which retains the original composition and structural characteristics. The magnetic hybrid aerogel possesses good ferromagnetic property with saturation magnetization value of 53.69 emu/g, enabling effective and controllable recovery of the aerogel under magnetic condition The adsorption efficiency of the hybrid aerogel on the Cr(VI) ion reaches the highest value of 2.2 mg/g when the mass ratio of the nanocellulose to ferroferric oxide nanoparticle is 1:1. Additionally, the hybrid aerogel presents similar adsorption behavior on plumbum (Pb)(II) and copper (Cu)(II) ions, suggesting extended applications of the hybrid aerogel on removal of heavy metal ions. Such strategy could provide new applications for the abundant nanocellulose resources and could be extended to integrate nanocellulose with other functional nanomaterials into novel hybrid aerogel for water purification. [ABSTRACT FROM AUTHOR]

The anaerobic fermentation of crop straw and animal wastes is increasingly used for the biogas and green energy generation, as well as reduction of the environmental pollution. The anaerobic cofermentation of corn stalks inoculated by cow dung was found to achieve higher biogas production and cellulose biodegradation. In this study, the effect of mixing corn stalks with cow dung at five different fermentation stages (0, 7, 15, 23, and 31 days of the total fermentation cycle of 60 days) on the further cofermentation process was explored, in order to optimize the corn straw utilization rate and biogas production capacity. In addition, the straw microstructure evolution was investigated by the SEM and XRD methods to identify the optimal conditions for the straw biodegradation process enhancement. The five test groups exhibited nearly identical total biogas productivity values but strongly differed by daily biogas yields (the maximal biogas generation rate being 524.3 ml/d). Based on the degradation characteristics of total solids (TS), volatile solids (VS), and lignocellulose, groups #1 and #3 (0 and 15 days) had the most significant degradation rates of VS (43.73%) and TS (42.07%), respectively, while the largest degradation rates of cellulose (62.70%) and hemicellulose (50.49%) were observed in group #4 (23 days) and group #1 (0 days), respectively. The SEM analysis revealed strong microstructural changes in corn stalks after fermentation manifested by multiple cracks and striations, while the XRD results proved the decrease in peak intensity of cellulose 002 crystal surface and the reduced crystallinity after cofermentation. The results of this study are assumed to be quite instrumental to the further optimization of the corn stalk anaerobic digestion by inoculation with digested manure for lignocellulose degradation enhancement and biogas productivity improvement. [ABSTRACT FROM AUTHOR]