Due to its lethal effect on the human body and other creatures, Cr(VI) ions have attained widespread public attention, and an effective adsorbent for removing Cr(VI) ions is vital. Chitosan (CS)/cellulose nanocrystals grafted with carbon dots (CNCD) composite hydrogel with strong sorption ability and sensitive detection ability for Cr(VI) was formed. The cellulose nanocrystals (CN) offered a natural skeleton for assembling 3D porous structures, and then improved the sorption ability for Cr(VI); moreover, carbon dots (CD) acted as a fluorescent probe for Cr(VI) and provided Cr(VI) adsorption sites. With a maximum adsorption capacity of 217.8 mg/g, the CS/CNCD composite hydrogel exhibited efficient adsorption properties. Meanwhile, with a detection limit of 0.04 μg/L, this hydrogel was used for selective and quantitative detection of Cr(VI). The determination of Cr(VI) was based on the inner filter effect (IFE) and static quenching. This hydrogel retained its effective adsorption ability even after four repeated regenerations. Furthermore, the economic feasibility of the CS/CNCD composite hydrogel over activated carbon was confirmed using cost analysis. This study provided one new method for producing low-cost adsorbents with effective sorption and sensitive detection for Cr(VI).

Water area and waterweed coverage are the key environmental factors for ecological breeding of Eriocheir sinensis in ponds. In order to explore the effects of above two factors on the growth of E. sinensis, three groups of experiments were set up: low coverage small area (C1S1), high coverage small area (C2S1), and high coverage large area (C2S2), and water environmental factors and the growth of E. sinensis were monitored. The results showed that the dissolved oxygen of ponds with different waterweed coverage was significantly different (p < 0.05), and the phosphate in ponds changed significantly from July to October (p < 0.05). The correlation analysis showed that NH₃-N and pH were significantly positively correlated (p < 0.05). At the same time, there was a significant negative correlation between NH₃-N and DO, H₃PO₄ and pH (p < 0.05). Further analysis of the relationship between surface area, waterweed coverage and environmental factors revealed that the surface area and waterweed coverage were closely related to NH₃-N, H₃PO₄ and DO. From July to October, the differences in morphology and weight of E. sinensis in different ponds became more and more significant. In terms of growth rate, C1S1 with a small area and low coverage had a downward trend, while C2S1 and C2S2 were the opposite. In the final stage of the experiment, C2S2 had the highest yield (0.1311 kg/m²), and C1S1 had the lowest yield (0.0600 kg/m²). Then, the ponds with high waterweed coverage and large area can bring better benefits.

The composition and diversity of microbial communities are of considerable significance to the quality development of Camellia sinensis (Fuzhuan tea). In this study, we examined differences in the bacterial community structures of loose, lightly-pressed, hand-made, and machine-pressed Fuzhuan teas and raw dark tea. We observed notable differences in the bacterial communities of the five groups, where there were only 51 consensus sequences. ASV/OTU Venn diagram, Chao1, Ace, Simpson indices, and dilution curve analyses consistently revealed that machine-pressed tea exhibited the highest bacterial diversity. Taxonomically, Actinobacteria, Firmicutes, Proteobacteria, and Cyanobacteria were the dominant bacterial phyla in each group, whereas Corynebacterium, Methylobacterium, and Bifidobacterium were the dominant genera. Our findings revealed significant differences in the bacterial community structures of different Fuzhuan tea products derived from the same raw material, with bacterial diversity rising with increased product compaction.

Larch tannin, a valuable forest product resource, offers the benefits of being natural, renewable and environmentally friendly. With growing environmental concerns, the widespread use of phenolic resins in the wood industry has been limited due to the depletion of fossil resources and formaldehyde emission issues. In this study, larch tannin was modified using a NaOH/urea solution to enhance phenolic resin properties. The curing properties and thermal stability of the adhesives were analyzed using a differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA), and the formaldehyde emissions were also measured. The results showed that this treatment effectively reduced the resin’s gel time. LTPF-U-4 resin demonstrated the highest bonding strength of 1.09 MPa and exhibited low formaldehyde emissions, thereby meeting the requirements for Class I plywood (≥0.7 MPa) and complying with the E0 grade of plywood standards as outlined in the China National Standard GB GB/T 17657-2013. The sodium hydroxide/urea-treated larch tannin substitution improved the bonding performance of the LTPF-U resins; its impact on bonding strength is limited. Nevertheless, the treatment significantly reduces the formaldehyde emissions of plywood bonded with LTPF-U resins. The NaOH/urea treatment not only reduced the thermal stability of the resin but also improved its curing properties and lowered its curing temperature. This research offers valuable insights for developing modified phenolic resins, which have significant practical implications.

Broussonetia papyrifera is a deciduous tree with significant economic and medicinal value. It demonstrates notable physiological adaptability to mining areas with severe manganese contamination and is a pioneering species in the field of ecological restoration. Flavonoids are vital secondary metabolites that improve plant resilience to environmental stresses. In the study presented herein, immature and mature fruits of B. papyrifera grown in normal and high manganese environments were used as the test materials. B. papyrifera fruit was subjected to transcriptome sequencing via high-throughput sequencing technology to analyze its flavonoid metabolic pathways and related genes. Transcriptome sequencing identified a total of 46,072 unigenes, with an average length of 1248 bp and a percentage of Q30 bases ranging from 92.45 to 93.17%. Furthermore, 31,792 unigenes (69% of the total) were annotated using eight databases, including the GO and KEGG. Analysis of KEGG metabolic pathways and flavonoid content trends in B. papyrifera fruits revealed four unigenes with strong links to the flavonoid biosynthesis pathway under manganese stress: flavone 3-hydroxylase, flavonoids 3′,5′-O-methyltransferase, chalcone synthase, and flavonol synthase. These unigenes may play important roles in regulating flavonoid synthesis in B. papyrifera fruits under manganese stress. This study lays the groundwork for functional gene research in B. papyrifera.